battery pack

Abstract

This battery pack is configured by arranging a plurality of battery cells 21 in a series. Each battery cell 21 has: a body 15; a thin plate-shaped positive electrode terminal 26 disposed along a long side-surface 15a, which is one of two opposing long side-surfaces 15a, 15b of the body; and a thin plate-shaped negative electrode terminal 27 provided along the other long side-surface 15b. The one long side-surface 15a of a battery cell 21 and the other long side-surface 15b of an adjacent battery cell 21 are disposed together so the positive electrode terminal 26 and the negative electrode terminal 27 are connected.

Description

[Technical Field]

[0001] The present invention relates to a connection structure of unit cells in a battery pack formed by combining a plurality of unit cells. [Background technology]

[0002] Many high-output, high-capacity batteries, such as those that supply power to vehicle drive motors, use assembled batteries made up of multiple battery cells (single cells).

[0003] For example, Patent Document 1 describes a battery pack (battery module) configured by arranging a plurality of rectangular battery cells (rectangular secondary batteries). In this battery pack, each battery cell has a positive terminal and a negative terminal on its top surface, and the battery cells are arranged so that the positive and negative electrodes of adjacent battery cells are adjacent to each other. The positive and negative electrodes of adjacent battery cells are connected to each other on the top surface of the battery pack by a bus bar made of an electrically conductive metal plate, thereby connecting the plurality of battery cells in series. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-80355 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a battery pack that requires high output, such as power to drive a vehicle, contains many battery cells, and therefore requires a large number of bus bars to match the number of battery cells. Therefore, the large number of bus bars increases the weight of the battery pack, and there is a risk that the battery pack will become larger in size in order to secure the installation space for the bus bars. In cases where the installation space for the battery pack is limited, such as in a vehicle, the volume of the battery cells must be reduced to secure the installation space for the many bus bars, resulting in a problem of reduced battery capacity.

[0006] The present invention has been made to solve these problems, and an object of the present invention is to provide a battery pack including a plurality of cells that can achieve both a small size of the entire battery pack and high output. [Means for solving the problem]

[0007] In order to achieve the above object, the battery pack of the present invention is a battery pack configured by arranging a plurality of unit cells in series, each unit cell having a main body portion, a positive electrode terminal provided on one of two opposing long side surfaces of the main body portion, and a negative electrode terminal provided on the other long side surface, the positive electrode terminal and the negative electrode terminal are thin plate-shaped conductors, the positive electrode terminal is arranged to extend along the one long side surface, the negative electrode terminal is arranged to extend along the other long side surface, a bag body covering the positive electrode terminal is provided on the one long side surface, and the negative electrode terminal is inserted into the bag body, The long side surface of one of the cells may be aligned with the long side surface of the other adjacent cell, and the positive electrode terminal and the electrode terminal may be connected.

[0008] This allows a plurality of cells to be arranged side by side with their long sides facing each other, so that the positive and negative terminals are connected, and the cells can be easily connected in series. Furthermore, since bus bars for connecting adjacent cells are no longer required, the weight of the battery pack can be reduced.Furthermore, since there is no need to detach bus bars when replacing some of the cells, maintenance is simplified. Furthermore, by arranging multiple cells side by side with their long sides facing each other, it is possible to reduce the dimensions in the direction in which the cells are arranged, and to easily configure a high-output battery pack by arranging many cells.

[0010] Also, The positive electrode terminal and the negative electrode terminal are thin plate-shaped conductors, and the positive electrode terminal is disposed so as to extend along one of the long side surfaces, and the negative electrode terminal is disposed so as to extend along the other long side surface. So, The space occupied by the positive and negative terminals can be reduced, and the positive and negative terminals can be easily connected by arranging the cells side by side.

[0011] Also, A bag body covering the positive electrode terminal is provided on one of the long sides, and when one long side of the cell and the other long side of the adjacent cell are arranged together, the negative electrode terminal is inserted into the bag body, and the positive electrode terminal and the negative electrode terminal are connected. So, The bag prevents the positive terminal from being exposed. R, When the battery pack is used alone, the positive terminal is prevented from contacting the surrounding conductors, thereby preventing short circuits between the positive and negative terminals. Furthermore, because the battery pack is a pouch, the distance between adjacent cells can be kept small when the cells are lined up and pressed down by the pressing portion, allowing for a more compact battery pack.

[0012] or, A bag body covering the negative electrode terminal is provided on one of the long sides, and when one long side of the cell and the other long side of the adjacent cell are arranged together, the positive electrode terminal is inserted into the bag body, and the positive electrode terminal and the negative electrode terminal are connected. That's fine. This prevents the negative terminal from being exposed, preventing the negative terminal from coming into contact with surrounding conductors when the cell is alone, and preventing a short circuit between the positive and negative terminals. Furthermore, the use of a bag minimizes the distance between adjacent cells when the cells are lined up and held down by the holding portion, allowing for a more compact battery pack.

[0014] Preferably, the battery pack further includes a pressing portion that presses down a plurality of the arranged unit cells together, The direction in which the pressing portion presses the unit cell may coincide with the direction in which the positive electrode terminal and the negative electrode terminal are connected. As a result, by holding down the plurality of single cells with the holding portion, the positive electrode terminals and the negative electrode terminals can be pressed together, facilitating connection. [Effects of the Invention]

[0015] In the battery pack of the present invention, by arranging a plurality of unit cells side by side, the positive and negative terminals can be easily connected. In addition, since a bus bar for connecting adjacent unit cells is not required, the weight of the battery pack can be reduced, and by utilizing the installation space for the bus bar, the overall battery pack can be made compact and have high output. Furthermore, the work of replacing the cells becomes easier, and maintenance can be improved. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a vertical cross-sectional view showing a schematic configuration of a battery pack according to a first embodiment of the present invention. [Figure 2] 2 is a longitudinal cross-sectional view of a battery cell in the battery pack of the first embodiment. FIG. [Figure 3] FIG. 2 is a side view of a battery cell in the battery pack of the first embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a schematic configuration of a battery pack according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a longitudinal cross-sectional view of a battery cell in a battery pack according to a second embodiment. [Figure 6] FIG. 10 is a vertical cross-sectional view showing the connection state of electrodes of adjacent battery cells according to the second embodiment. [Figure 7] FIG. 10 is a vertical cross-sectional view showing a schematic configuration of a battery pack according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a side view of one battery cell in the battery pack of the third embodiment. [Figure 9] FIG. 11 is another side view of the battery cell in the battery pack of the third embodiment. [Figure 10]FIG. 10 is a front view of a battery cell in a battery pack according to a third embodiment. [Figure 11] FIG. 10 is a vertical cross-sectional view showing a schematic configuration of a battery pack according to a fourth embodiment of the present invention. [Figure 12] FIG. 10 is a side view of one battery cell in the battery pack of the fourth embodiment. [Figure 13] FIG. 10 is another side view of the battery cell in the battery pack of the fourth embodiment. [Figure 14] FIG. 10 is a front view of a battery cell in a battery pack according to a fourth embodiment. [Figure 15] FIG. 10 is a vertical cross-sectional view showing the connection state of electrodes of adjacent battery cells according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a battery pack embodying the present invention will be described. First Embodiment

[0018] Fig. 1 is a vertical cross-sectional view showing a schematic configuration of a battery pack 1 according to a first embodiment of the present invention. Fig. 2 is a vertical cross-sectional view of a battery cell 10 in the battery pack 1 according to the first embodiment. Fig. 3 is a side view of a battery cell 10 in the battery pack 1 according to the first embodiment.

[0019] The battery pack 1 of this embodiment is a high-voltage, high-capacity battery such as a battery that supplies power to the driving motor of an electric vehicle, a plug-in hybrid vehicle, a hybrid vehicle, etc., and is composed of a combination of multiple battery cells 10 (single cells), for example, made of lithium-ion batteries.

[0020] As shown in FIG. 1, the battery pack 1 is configured by arranging rectangular box-shaped battery cells 10 in series. The battery pack 1 also includes a support bracket 2 (holding portion) that collectively supports the multiple battery cells 10 in an aligned state. The support bracket 2 has a pair of support portions 2a that hold down the battery cells 10 at both ends of the aligned battery cells 10, and a connecting portion 2b that connects the pair of support portions 2a, 2a. The connecting portion 2b extends along the group of aligned battery cells 10 and is positioned so as to hold down both side surfaces of the group of aligned battery cells 10.

[0021] As shown in FIGS. 2 and 3 , the battery cell 10 used in the battery pack 1 of the first embodiment has a rectangular box-shaped main body 15, a positive terminal 16 protruding from the main body 15, and a negative terminal 17 built into the main body 15.

[0022] The main body 15 is constructed by housing a rolled positive and negative electrode plates with a separator sandwiched between them in a rectangular box-shaped housing. The internal structure of the battery cell 10, including the separator, positive and negative electrode plates, is similar to that of, for example, a known prismatic lithium-ion battery, and detailed descriptions of the materials and structure are omitted here.

[0023] Of the vertical sides, horizontal sides, and thickness of the rectangular box-like body 15, the vertical sides are the longest, the horizontal sides are the next longest, and the thickness is the shortest. Therefore, of the six faces of the rectangular box, the two opposing long side faces 15a, 15b, which are made up of the vertical and horizontal sides, have larger areas than the other faces. The positive electrode terminal 16 is provided on one of the two long side surfaces 15a, 15b, the long side surface 15a, and is positioned at a position offset a predetermined distance from the center of the long side surface 15a toward the lower surface 15d. The positive electrode terminal 16 has, for example, a conical shape with a protruding mountain shape and a truncated tip.

[0024] The negative electrode terminal 17 is provided on the other long side surface 15b of the two long sides 15a, 15b, and is positioned at a position offset a predetermined distance from the center position of the long side surface 15b toward the top surface 15c. The negative electrode terminal 17 is formed, for example, as a conical recess, so that the positive electrode terminal 16 fits into it and the circumferential surface abuts on it with almost no gap.

[0025] The positive terminal 16 and the negative terminal 17 are arranged at positions offset in the direction of the horizontal side of the main body 15 (left and right direction in Figure 3), and are arranged at positions that are point-symmetrical with the center position 0 of the main body 15 as the center of symmetry, i.e., at diagonal positions on the main body 15.

[0026] As shown in FIG. 1, when the battery cells 10 are arranged side by side with the long sides 15a and 15b of the main body portions facing each other, the positive terminal 16 of the adjacent battery cell 10 fits into the negative terminal 17 and is connected.

[0027] When a predetermined number of battery cells 10 are arranged in series and the positive terminals 16 and negative terminals 17 are connected, the battery cells 10 at both ends are held down by the support brackets 2, so that the positive terminals 16 and negative terminals 17 of all adjacent battery cells 10 are connected.

[0028] The battery pack 1, which is configured from a plurality of battery cells 10 in this manner, is further connected in series or parallel to be mounted on a vehicle.

[0029] As described above, the rectangular battery cells 10 used in the battery pack 1 of the first embodiment are provided with a positive terminal 16 on one of the two opposing long sides of the rectangular box-shaped main body 15, and a negative terminal 17 on the other. By arranging a plurality of battery cells 10 with their long sides 15a, 15b aligned, the positive terminal 16 and the negative terminal 17 are connected, making it possible to easily connect the battery cells 10 in series.

[0030] Furthermore, since there is no need for bus bars to connect the terminals of adjacent battery cells 10, it is possible to reduce the weight of the battery pack 1. Furthermore, since there is no need to detach bus bars when replacing some of the multiple battery cells 10, maintenance is easier.

[0031] Furthermore, by arranging the long sides 15a, 15b of the battery cells 10 together, the battery cells 10 are arranged in a relatively short thickness direction of the battery cells 10. Therefore, it is possible to easily configure a high-output assembled battery 1 by arranging many battery cells 10 while suppressing the dimension in the direction in which the battery cells 10 are arranged.

[0032] In addition, the positive electrode terminal 16 is formed in a convex shape and the negative electrode terminal 17 is formed in a concave shape, and when the long side surface 15a of the main body 15 of the battery cell 10 and the long side surface 15b of the adjacent battery cell 10 are aligned, the positive electrode terminal 16 is inserted into the negative electrode terminal 17, making it possible to easily connect the positive electrode terminal 16 and the negative electrode terminal 17.

[0033] In addition, the positive electrode terminal 16 and the negative electrode terminal 17 are disposed diagonally in the main body 15. Thus, even if the battery cells 10 are erroneously arranged so that the long sides 15a or the long sides 15b face each other when they are lined up, connection between the positive terminals 16 or the negative terminals 17 can be avoided.

[0034] The battery pack 1 also includes a support bracket 2 that holds down multiple aligned batteries together, and the direction in which the support bracket 2 holds down the battery cells 10 coincides with the direction in which the positive terminal 16 and negative terminal 17 are connected.

[0035] As a result, by pressing down multiple battery cells 10 together with the support bracket 2, the positive electrode terminal 16 and the negative electrode terminal 17 can be pressed together and reliably connected. Second Embodiment

[0036] Fig. 4 is a vertical cross-sectional view showing the schematic configuration of a battery pack 20 according to a second embodiment of the present invention. Fig. 5 is a vertical cross-sectional view showing the structure of a battery cell 21, and Fig. 6 is a vertical cross-sectional view showing the connection state of electrode terminals of adjacent battery cells 21 according to the second embodiment. Only the differences from the first embodiment will be described below.

[0037] The battery cell 21 of the second embodiment differs from the battery cell 10 of the first embodiment in the structure of the positive and negative terminals. As shown in Figures 4 to 6, the positive electrode terminal 26 and the negative electrode terminal 27 of the battery cell 21 of the second embodiment are formed from thin plates of a conductive material such as copper. The positive electrode terminal 26 is provided along one of the two long sides 15a, 15b, the long side 15a, and the negative electrode terminal 27 is provided along the other long side 15b. The positive electrode terminal 26 is connected to the positive electrode plate inside the main body 15 near one longitudinal end of the long side 15a (the bottom surface 15d in Figure 4). The negative electrode terminal 27 is connected to the negative electrode plate inside the main body 15 near the other longitudinal end of the long side 15b (the top surface 15c in Figure 4).

[0038] A bag-shaped pocket 28 (bag body) made of an insulating film or the like is provided on the long side surface 15a of the main body 15 on the side of the positive terminal 26. The positive terminal 26 is housed inside the pocket 28 and is arranged so that the positive terminal 26 is not exposed to the outside of the pocket 28. The other end side of the pocket 28 is open.

[0039] 4 and 6, when the battery cells 21 are arranged side by side with the long sides 15a and 15b of the main body 15 facing each other, the negative terminals 27 are inserted into the pockets 28. This connects the positive and negative terminals 26 and 27 of adjacent battery cells 21 in the pockets 28.

[0040] As in the first embodiment, by arranging a predetermined number of battery cells 21 in series and holding down the battery cells 21 at both ends with the support bracket 2, the positive electrode terminals 26 and negative electrode terminals 27 of all adjacent battery cells 21 are pressed against each other and securely connected. Furthermore, because the positive electrode terminals 26 and negative electrode terminals 27 are thin plate-shaped and the pockets 28 are also made of a film-like material, the space occupied by the positive electrode terminals 26, negative electrode terminals 27, and pockets 28 can be reduced. This ensures a large mounting space for the positive electrode plates and negative electrode plates in the main body 15, thereby increasing capacity.

[0041] Alternatively, the negative terminal 27 may be provided inside the pocket 28, and the positive terminal 26 may be provided on the long side surface 15b of the main body 15. <Third embodiment>

[0042] Fig. 7 is a vertical cross-sectional view showing the schematic configuration of a battery pack 30 according to a third embodiment of the present invention. Figs. 8 to 10 show the structure of a battery cell 31 in the battery pack 30 according to the third embodiment, with Fig. 8 being one side view, Fig. 9 being the other side view, and Fig. 9 being a front view.

[0043] The battery cells 31 used in the battery pack 30 of the third embodiment are laminated battery cells in which the main body 35 is covered with a laminate film.

[0044] 8 to 10, the battery cell 31 of the third embodiment has a thinner main body 35 than the battery cell 21 of the second embodiment. A positive terminal 36 is provided on one long side surface 35a of the main body 35, and a negative terminal 37 is provided on the other long side surface 35b.

[0045] The positive terminal 36 and the negative terminal 37 are formed of a thin plate that is both conductive and elastic, such as a copper plate, etc. The positive terminal 36 protrudes from one end 35d (the right end in FIGS. 8 to 10) in the long side direction (vertical direction) of the main body 35, is folded back toward one long side surface 35a, and extends in the long side direction of the main body 35 along the long side surface 35a toward the other end 35c (the left end in FIGS. 8 to 10), with its tip end 36a located in the range from the middle position of the main body 35 in the vertical direction to the other end 35c.

[0046] On the other hand, the negative electrode terminal 37 protrudes from the other end 35c (left end in Figures 8 to 10) in the long side direction of the main body portion 35, is folded back toward the other long side surface 35b of the main body portion 35, and extends in the long side direction of the main body portion 35 along the long side surface 35b toward one end 35d, with its tip portion 37a located in the range from the midpoint in the long side direction of the main body portion 35 to one end 35d.

[0047] The width (vertical width in FIGS. 8 and 9) of the positive terminal 36 and the negative terminal 37 is such that they can be disposed within the width (vertical width in FIGS. 8 and 9) of the main body 35.

[0048] As shown in Figure 7, the battery cells 31 are arranged in the same direction with the long side surfaces 35a and 35b of the main body portions 35 aligned. For example, the battery cells 31 are arranged side by side with the other end portions 35c of the main body portions facing upward, toward the extension of the support bracket 2. At this time, the tip portions 37a of the negative terminals 37 of the adjacent battery cells 31 are inserted between the positive terminals 36 of the battery cells 31 and the long side surfaces 35a of the main body portions 35, thereby connecting the positive terminals 36 and negative terminals 37 of the adjacent battery cells. Note that the battery cells 31 may be arranged with one end portion 35d of the main body portions facing the support bracket 2.

[0049] As in the first and second embodiments, a predetermined number of battery cells 31 are arranged in series with their positive terminals 36 and negative terminals 37 connected, and then the battery cells 31 at both ends are pressed down by the support brackets 2, thereby reliably connecting the positive terminals 36 and negative terminals 37 of all adjacent battery cells 31.

[0050] In addition, since the battery cells 31 of this embodiment are laminated battery cells, they can be made thinner than the rectangular battery cells 10 and 21 of the first and second embodiments, and more battery cells 31 can be installed, thereby achieving higher output for the battery pack 30. <Fourth embodiment>

[0051] Fig. 11 is a vertical cross-sectional view showing the schematic configuration of a battery pack 40 according to a fourth embodiment of the present invention. Figs. 12 to 14 show the structure of a battery cell 41 in the battery pack 40 according to the fourth embodiment, with Fig. 12 being one side view, Fig. 13 being the other side view, and Fig. 14 being a front view. Fig. 15 is an explanatory diagram showing how adjacent battery cells 41 are connected.

[0052] As shown in FIGS. 12 to 14, a battery cell 41 used in a battery pack 40 of the fourth embodiment is provided with a pocket 48 on the positive terminal 36 side, in comparison with the battery cell 31 of the third embodiment.

[0053] Like the pocket 28 of the second embodiment, the pocket 48 is made of an insulating film or the like, and houses the positive electrode terminal 36. The pocket 48 is formed so as to completely cover the portion of one end 35d of the main body 35 from which the positive electrode terminal 36 protrudes, and is open on the other end 35c side.

[0054] 14 , when the battery cells 41 are arranged side by side with the long side surface 35a of the main body 35 and the long side surface 35b of the adjacent battery cell 41 aligned, the negative terminal 37 is inserted into the pocket 48. This connects the positive terminal 36 and the negative terminal 37 of the adjacent battery cells 31 inside the pocket 48.

[0055] In the fourth embodiment, one end 35d of the main body 35 from which the positive terminal 36 protrudes is disposed on the support bracket 2 side, but the other end 35c may be disposed on the support bracket 2 side.

[0056] As described above, in this embodiment, as in the second embodiment, by providing a pocket 48 for storing the positive terminal 36, it is possible to prevent the positive terminal 36 from being exposed when the battery cell 41 is in a standalone state. This prevents a conductive object from coming into contact with the positive terminal 36, even if such an object is present around the single battery cell 41. This prevents short-circuiting between the positive terminal 36 and the negative terminal 37, making it easier to handle and store the battery cell 41.

[0057] Although the description of the embodiment has been completed, aspects of the present invention are not limited to the above embodiment. For example, the mounting orientation of the battery pack in the vehicle may be changed as appropriate. Furthermore, the detailed shape or configuration of the battery cells and the battery pack may be changed as appropriate.

[0058] The battery pack of the present invention can be applied to battery packs mounted on various vehicles, and can also be widely applied to battery packs for purposes other than vehicles. [Explanation of symbols]

[0059] 1, 20, 30, 40 battery packs 2 Support bracket (holding part) 10, 21, 31, 41 Battery cells (single cells) 15, 35 Main body 16, 26, 36 Positive terminal 17, 27, 37 Negative terminal 15a, 15b, 35a, 35b long side 28, 48 pockets (bag body)

Claims

1. A battery pack configured by arranging a plurality of cells in series, The cell has a main body, a positive electrode terminal provided on one of two opposing long side surfaces of the main body, and a negative electrode terminal provided on the other long side surface, The positive electrode terminal and the negative electrode terminal are thin plate-shaped conductors, The positive electrode terminal is disposed so as to extend along the one long side surface, the negative electrode terminal is disposed so as to extend along the other long side surface, a bag body covering the positive electrode terminal on the one long side surface; The negative electrode terminal is inserted into the bag, and the long side surface of one of the cells is aligned with the long side surface of the other adjacent cell, and the positive electrode terminal and the negative electrode terminal are connected. A battery pack characterized by:

2. A battery pack configured by arranging a plurality of cells in series, The cell has a main body, a positive electrode terminal provided on one of two opposing long side surfaces of the main body, and a negative electrode terminal provided on the other long side surface, The positive electrode terminal and the negative electrode terminal are thin plate-shaped conductors, The positive electrode terminal is disposed so as to extend along the one long side surface, the negative electrode terminal is disposed so as to extend along the other long side surface, a bag body covering the negative electrode terminal on the other long side surface; The positive electrode terminal is inserted into the bag, and the long side surface of one of the cells is aligned with the long side surface of the other adjacent cell, and the positive electrode terminal and the negative electrode terminal are connected. A battery pack characterized by:

3. a pressing portion that presses down the plurality of arranged unit cells together, The direction in which the pressing portion presses the unit cell coincides with the direction in which the positive electrode terminal and the negative electrode terminal are connected.

3. The battery pack according to claim 1 or 2.

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