Battery pack

Abstract

To provide a battery pack in which electrical connection of a plurality of battery cells can be easily performed.SOLUTION: A cell unit 20 of a battery pack includes a high potential-side battery set 21H and a low potential-side battery set 21L, each battery set including a plurality of cells 21. The cells 21 each include a first end 21a and a second end 21b which are both ends in an axial direction, and a positive electrode terminal and a negative electrode terminal which are disposed on a first end 21a side. The plurality of cells 21 in each of the battery sets 21H, 21L are disposed along an adhesive surface 23A of each holding member 23 while the orientations of the first ends 21a and the second ends 21b are aligned, and are electrically connected to each other. The first end 21a of each of the plurality of cells 21 of the high potential-side battery set 21H and the first end 21a of each of the plurality of cells 21 of the low potential-side battery set 21L are disposed at positions facing to each other in the axial direction by folding back a connection conductive member 34.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] In recent years, research and development into secondary batteries that contribute to energy efficiency has been conducted to ensure that more people have access to affordable, reliable, sustainable and advanced energy. Conventionally, for example, a battery pack has been known that includes two battery core packs having a plurality of battery cells arranged in a matrix, and a bus bar plate that electrically connects the two battery core packs (see, for example, Patent Document 1).

[0003] 12 includes two battery core packs 60 and a control unit 70 housed in a housing 51. The housing 51 includes a lid-shaped top case 51a and a bottom case 51b, and a cylindrical outer shell case (not shown) disposed between the top case 51a and the bottom case 51b. The two battery core packs 60 consist of a first pack 60a and a second pack 60b. Each battery core pack 60 includes a plurality of battery cells 80, a pair of cell holders 82 (a first holder 82a and a second holder 82b) that hold each battery cell 80 from both axial ends of the central axis, a plurality of bus bar plates 83, and a plurality of heat transfer sheets 84. Each battery cell 80 has a cylindrical outer shape. Each battery cell 80 includes a positive terminal 86 and a negative terminal 88 at both axial ends of the central axis.

[0004] The battery cells 80 are configured into seven cell sets, each consisting of six battery cells 80 with the same arrangement of positive and negative electrodes. The seven cell sets are arranged side by side in the vertical direction, and are set so that the arrangement of positive and negative electrodes of adjacent cell sets in the vertical direction is reversed. The multiple bus bar plates 83 are arranged at both axial ends of the multiple battery cells 80. The multiple bus bar plates 83 sequentially connect seven cell sets in series along the vertical direction, in which the arrangement of positive and negative electrodes is alternately reversed along the vertical direction. Of the multiple bus bar plates 83, the bus bar plate 83a connecting the first pack 60a and the second pack 60b in series connects the upper cell sets of each of the first pack 60a and the second pack 60b in series. The seven cell sets of the first pack 60a and the seven cell sets of the second pack 60b are connected in series by the multiple bus bar plates 83 and then connected to external connection terminals via the control unit 70. The plurality of heat transfer sheets 84 thermally connect each bus bar plate 83 to the outer shell case of the housing 51 at one end side of the plurality of battery cells 80 in the axial direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-16096 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in technologies related to secondary batteries, it is necessary to prevent the electrical connection structure between multiple battery cells and conductive members such as bus bar plates from becoming complicated and the connection length from increasing. For example, in the battery pack of the above-mentioned conventional technology, each battery core pack includes a bus bar plate that connects positive and negative terminals at both ends of multiple battery cells. This results in problems such as complicated electrical connection and a long connection length.

[0007] The present invention aims to solve the above-mentioned problems by facilitating the electrical connection of multiple battery cells, which in turn contributes to improving energy efficiency. [Means for solving the problem]

[0008] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A battery pack according to one aspect of the present invention includes a first battery group (e.g., a high-potential battery group 21H in the embodiment) including a plurality of battery cells (e.g., cells 21 in the embodiment), and a second battery group (e.g., a low-potential battery group 21L in the embodiment) including a plurality of battery cells (e.g., cells 21 in the embodiment), and the battery cells have a first end (e.g., first end 21a in the embodiment) and a second end (e.g., second end 21b in the embodiment) that are both ends in a predetermined direction (e.g., an axial direction in the embodiment), and a second end (e.g., second end 21b) disposed on the first end side. The first battery group and the second battery group each have a positive terminal (e.g., positive terminal 21P in the embodiment) and a negative terminal (e.g., negative terminal 21N in the embodiment) that face each other, and the plurality of battery cells in each of the first battery group and the second battery group are arranged along a predetermined mounting surface (e.g., adhesive surface 23A in the embodiment) with the first end and the second end oriented in the same direction, and are electrically connected to each other, and the first end of the plurality of battery cells in the first battery group and the first end of the plurality of battery cells in the second battery group are arranged in positions facing each other in the predetermined direction.

[0009] (2): The battery pack described in (1) above may include a terminal conductive member (e.g., the negative electrode connection portion 34a and the positive electrode connection portion 34b in the embodiment) that connects the positive electrode terminals or the negative electrode terminals of the plurality of battery cells in at least one of the first battery group and the second battery group, and a battery group conductive member (e.g., the connection conductive member 34 in the embodiment) that is formed integrally with the terminal conductive member and electrically connects the first battery group and the second battery group.

[0010] (3) In the battery pack described in (2) above, a part of the battery assembly conductive member may be an easily bendable portion having a relatively low bending rigidity (for example, the easily bendable portion 34f in the embodiment).

[0011] (4): In the battery pack described in (3) above, the length of the easy-to-bend portion in the longitudinal direction along the width direction of the battery assembly conductive member may be relatively smaller than the width of the battery assembly conductive member.

[0012] (5) In the battery pack according to any one of (1) to (4) above, the battery cells may have a cylindrical outer shape. [Effects of the Invention]

[0013] According to the above (1), the orientation of the first ends where the positive and negative terminals are provided in the multiple battery cells of each battery group is aligned, which facilitates joining of each terminal to a conductive member such as a bus bar. The first ends of the multiple battery cells of the first battery group and the first ends of the multiple battery cells of the second battery group are arranged in positions facing each other, which facilitates connection between the conductive member on the first battery group side and the conductive member on the second battery group side, or prevents an increase in the length of the wiring required for connection.

[0014] In the case of (2) above, by providing a battery group conductive member formed integrally with the terminal conductive member, the electrical connection of the first battery group and the second battery group can be easily performed in a consolidated manner, along with the electrical connection of the multiple battery cells in each battery group.

[0015] In the case of (3) above, by providing a portion of the terminal conductive member with an easy-to-bend portion, even if the terminal conductive member is bent so as to fold back at the easy-to-bend portion after the electrical connection is made, it is possible to prevent stress from acting on the electrical connection portion.

[0016] In the case of (4) above, the bending rigidity can be further reduced by reducing the length of the easy-to-bend portion.

[0017] In the case of (5) above, short-circuiting of the potential between adjacent cells can be suppressed compared to other shapes such as a prismatic shape. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a battery pack according to an embodiment of the present invention; [Figure 2] 1 is an exploded perspective view showing a configuration of a battery pack according to an embodiment of the present invention; [Figure 3] 1 is a cross-sectional view showing a configuration of a battery pack according to an embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view showing the configuration of a cell unit in the battery pack according to the embodiment of the present invention. [Figure 5] FIG. 2 is a perspective view showing the configuration of a cell unit before folding in a battery pack according to an embodiment of the present invention. [Figure 6] FIG. 2 is a diagram showing an electrical connection state of a plurality of cells in a battery pack according to an embodiment of the present invention. [Figure 7] FIG. 3 is a perspective view showing the configuration of a second positive electrode conductor, an insulating member, and a second negative electrode conductor in the battery pack according to the embodiment of the present invention. [Figure 8] FIG. 2 is a perspective view showing the configuration of a connecting conductive member, a second positive conductive member, an insulating member, and a second negative conductive member in the battery pack according to the embodiment of the present invention. [Figure 9] FIG. 3 is a cross-sectional view showing a connecting conductive member in the battery pack according to the embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view showing the configuration of a cell unit before folding back a battery pack in a first modified example of an embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view showing the configuration of a cell unit after folding back a battery pack in a second modified example of the embodiment of the present invention. [Figure 12] FIG. 1 is an exploded perspective view showing the configuration of a conventional battery pack that is a comparative example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a battery pack according to an embodiment of the present invention will be described with reference to the accompanying drawings. The battery pack 10 of the embodiment is, for example, a battery that can be attached to and detached from various electric power devices. The electric power devices to which the battery pack 10 can be attached and detached include, for example, electric vehicles, electric mobile objects, electric machines, power supply devices, and various electrical equipment. Examples of electric vehicles include electric automobiles, saddle-type vehicles, and kick scooters that have a rotating electric machine driven by the power of the battery pack 10 as a power source, hybrid vehicles that combine a rotating electric machine with an internal combustion engine, and fuel cell vehicles that combine the battery pack 10 with a fuel cell. Examples of electric mobile objects include robots, aircraft, and floating and underwater mobile objects. Examples of electric machines include, for example, construction machinery that has a rotating electric machine as a power source. Examples of power supplies include, for example, stationary or mobile power supplies that discharge and charge the battery pack 10.

[0020] Fig. 1 is a perspective view of a battery pack 10 according to an embodiment. Fig. 2 is an exploded perspective view showing the configuration of the battery pack 10 according to an embodiment. Fig. 3 is a cross-sectional view showing the configuration of the battery pack 10 according to an embodiment. In the following description, the X-axis, Y-axis, and Z-axis directions, which are orthogonal to each other in three-dimensional space, are parallel to each other. For example, as shown in Figures 1, 2, and 3, the X-axis direction is parallel to the left-right direction of the battery pack 10, the Y-axis direction is parallel to the front-rear direction of the battery pack 10, and the Z-axis direction is parallel to the up-down direction of the battery pack 10. For example, the positive direction of the X-axis is the left direction of the battery pack 10, the positive direction of the Y-axis is the front direction of the battery pack 10, and the positive direction of the Z-axis is the up direction of the battery pack 10.

[0021] 1, 2, and 3, the battery pack 10 has, for example, a box-like outer shape with a grip portion 11a. The battery pack 10 is a replaceable, so-called cassette-type battery pack (secondary battery). The battery pack 10 includes, for example, a top case 11, a bottom case 13, and a middle case 15. For example, the top case 11 and the bottom case 13 each have an open box-like outer shape. For example, the middle case 15 has a cylindrical outer shape. The top case 11 and the bottom case 13 close the open ends at both ends in the axial direction along the central axis of the middle case 15.

[0022] The top case 11 includes a grip portion 11a that is gripped by, for example, the hand of an operator. The outer shape of the grip portion 11a is, for example, a T-shape formed by two rod-shaped members protruding from three different positions on the upper part of the top case 11. For example, the rod-shaped members protruding from two left and right positions and extending in the left-right direction and the rod-shaped member protruding from one rear position and extending in the front-rear direction are integrally connected perpendicular to each other to form the T-shaped grip portion 11a that is bilaterally symmetrical.

[0023] The top case 11 has, for example, two pairs of front and rear fastening portions 11b that protrude downward from the left and right sides of the lower interior portion. A first connecting portion 23b of each holding member 23 is fastened and fixed to each pair of fastening portions 11b by two first fastening members 24 (described later). Each fastening portion 11b has, for example, a female-threaded hole (screw hole) formed along the left-right direction, into which the first fastening member 24 is attached, and the first fastening member 24 is fastened from the outside in the left-right direction. For example, each fastening portion 11b, each first connecting portion 23b, and each first fastening member 24 are fastened only to the inside of the top case 11 without being exposed to the outside, and are covered by the middle case 15. A recessed groove 11c extending, for example, along the front-rear direction is formed in the center in the left-right direction of the lower part of the top case 11. An upper part 35a of a separation sheet 35, which will be described later, is inserted into the recessed groove 11c.

[0024] The bottom case 13 has, for example, two pairs of front and rear fastening portions 13a that protrude upward from the four corners of the upper portion. Each pair of fastening portions 13a fastens and fixes the respective holding members 23 and the control unit holding member 17 with second fastening members 25, which will be described later. Each fastening portion 13a is formed with a female-threaded hole (screw hole) that passes through in the vertical direction, into which, for example, the second fastening member 25 is attached, and the second fastening member 25 is fastened from the outside on the lower side in the vertical direction. A recessed groove 13b extending, for example, along the front-rear direction is formed in the center in the left-right direction of the upper part of the bottom case 13. A lower part 35b of a separation sheet 35, which will be described later, is inserted into the recessed groove 13b.

[0025] The bottom case 13 has, for example, a connection portion (not shown) exposed downward from the center of the lower portion. The connection portion has, for example, connection terminals for power lines for transmitting and receiving power and communication lines for transmitting and receiving information. The connection portion is connected, for example, to connection portions of various power devices and replacement units. For example, the connection portion of the battery pack 10 is a female connector, and the connection portions of the various power devices and replacement units are male connectors. When the connection portion of the battery pack 10 is connected to the connection portion of the various power devices or replacement units, power is exchanged and information is exchanged between the battery pack 10 and the various power devices or replacement units.

[0026] The battery pack 10 includes, for example, a control unit holding member 17, a control unit 19, and a cell unit 20, which are arranged in an internal space formed by a top case 11, a bottom case 13, and a middle case 15. The control unit holding member 17 has, for example, a plate-like outer shape. The control unit holding member 17 holds, for example, the control unit 19 arranged on the lower side. The control unit holding member 17 has, for example, four through-holes formed at the four corners thereof, penetrating in the thickness direction. The control unit holding member 17 is attached to the second connection portions 23c of the two holding members 23 from above in the vertical direction, with the four through-holes communicating with two through-holes in each of the second connection portions 23c of the two holding members 23 (described later) and with the screw holes in the two pairs of front and rear fastening portions 13a of the bottom case 13. The control unit holding member 17 is fastened and fixed to the bottom case 13 together with the two holding members 23 by second fastening members 25 (described later).

[0027] The control unit 19 is, for example, a so-called BMU (Battery Management Unit), which monitors and controls the state of the cell unit 20. The control unit 19 is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU (Electronic Control Unit) that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the control unit 19 may be an integrated circuit such as an LSI (Large Scale Integration).

[0028] The control unit 19 includes, for example, various sensors that detect the state of the cell unit 20, and a storage unit that stores information about the battery pack 10, predetermined programs, and the like. The state of the cell unit 20 is, for example, voltage, current, temperature, etc. The information about the battery pack 10 includes, for example, identification information such as a battery ID (identifier) ​​exclusively assigned to the battery pack 10, information about the state of the cell unit 20 based on the manufacturing date and time, initial capacity, sensor output, etc., charge and discharge history, storage time in the replacement unit, and usage history, etc.

[0029] FIG. 4 is a perspective view showing the configuration of a cell unit 20 in a battery pack 10 according to an embodiment. FIG. 5 is a perspective view showing the configuration of a cell unit 20 in a battery pack 10 according to an embodiment before folding. FIG. 6 is a view showing the electrical connection state of a plurality of cells 21 in a battery pack 10 according to an embodiment. FIG. 7 is a perspective view showing the configuration of a second positive electrode conductor 31, an insulating member 32, and a second negative electrode conductor 33 in a battery pack 10 according to an embodiment. FIG. 8 is a perspective view showing the configuration of a second positive electrode conductor 31, an insulating member 32, a second negative electrode conductor 33, and a connecting conductive member 34 in a battery pack 10 according to an embodiment. FIG. 9 is a cross-sectional view showing a connecting conductive member 34 in a battery pack 10 according to an embodiment.

[0030] As shown in Figures 4 and 5, the cell unit 20 includes, for example, a plurality of battery cells (cells) 21, an adhesive 22, two holding members 23, four first fastening members 24 and four second fastening members 25, a first positive electrode conductive member 31P, a plurality of second positive electrode conductive members 31, a plurality of insulating members 32, a first negative electrode conductive member 33N, a plurality of second negative electrode conductive members 33, a connecting conductive member 34, and a separation sheet 35. Each battery cell (cell) 21 is, for example, a secondary battery such as a lead acid battery, a lithium ion battery, a sodium ion battery, a nickel-metal hydride battery, or an all-solid-state battery, a capacitor such as an electric double layer capacitor, or a composite battery that combines a secondary battery and a capacitor. Each cell 21 is repeatedly charged and discharged.

[0031] The plurality of cells 21 are, for example, two sets of 42 cells 21 arranged in 6 rows and 7 columns, totaling 84 cells 21. The two sets are, for example, a high-potential side battery set 21H and a low-potential side battery set 21L. As shown in Figures 4, 5, 6, and 7, the outer shape of each cell 21 is, for example, cylindrical. The positive electrode terminal 21P and the negative electrode terminal 21N of each cell 21 are provided, for example, on one end (first end 21a) side of both axial end portions (first end 21a and second end 21b) of each cell 21 along the central axis of the cell 21. The outer shape of the positive electrode terminal 21P is, for example, a disk shape that protrudes in the axial direction from the center of the first end 21a. The outer shape of the negative electrode terminal 21N is, for example, an annular shape that protrudes in the axial direction from the peripheral edge portion of the first end 21a so as to surround the positive electrode terminal 21P.

[0032] 2, 3, 4, and 5, for example, the 42 cells 21 of each battery set 21H, 21L are arranged along the adhesive surface 23A of each holding member 23 with the first end 21a and the second end 21b oriented in the same direction. For example, the second end 21b of the cells 21 of each battery set 21H, 21L is adhered and fixed to the adhesive surface 23A of each holding member 23 with adhesive 22. The outer shape of each of the two holding members 23 is, for example, a plate shape with curved ends in the longitudinal direction. Each holding member 23 is made of a metal material such as aluminum. Each holding member 23 is formed by, for example, extrusion molding.

[0033] Each holding member 23 includes, for example, a cell holding portion 23a, a first connecting portion 23b, and a second connecting portion 23c. The cell holding portion 23a has an outer shape of, for example, a flat plate. One of the two surfaces of the cell holding portion 23a in the thickness direction is an adhesive surface 23A to which a set of 42 cells 21 is adhesively fixed with an adhesive 22. For example, the axial direction of each cell 21 is parallel to the thickness direction of the cell holding portion 23a, and a second end 21b of each cell 21, which is on the opposite side of the positive electrode terminal 21P and the negative electrode terminal 21N in the axial direction, is fixed to the adhesive surface 23A with the adhesive 22.

[0034] The first connecting portion 23b and the second connecting portion 23c are curved, for example, at both longitudinal ends of the cell holding portion 23a so as to protrude from the bonding surface 23A along the thickness direction. The outer shape of the first connecting portion 23b is, for example, an L-shaped plate shape that protrudes from the bonding surface 23A along the thickness direction of the cell holding portion 23a and then curves outward along the longitudinal direction. The outer shape of the second connecting portion 23c is, for example, a flat plate shape that protrudes from the bonding surface 23A along the thickness direction of the cell holding portion 23a. Two through holes are formed in the first connecting portion 23b, penetrating the cell holding portion 23a in the thickness direction. The first connecting portion 23b is attached to the pair of front and rear fastening portions 11b from the outside in the left-right direction so that the two through holes are connected to the screw holes of the pair of front and rear fastening portions 11b of the top case 11. The second connecting portion 23c has two through holes formed therein that penetrate the cell holding portion 23a in the longitudinal direction. The second connecting portion 23c is attached to the pair of front and rear fastening portions 13a of the bottom case 13 from above in the vertical direction so that the two through holes are connected to the screw holes of the pair of front and rear fastening portions 13a.

[0035] Each of the first fastening member 24 and the second fastening member 25 is, for example, a male screw. Each first fastening member 24 is fastened to the top case 11 and the holding member 23 by, for example, being attached from the outside of the top case 11 in the left-right direction to the through hole of the first connection portion 23b of the holding member 23 and the screw hole of the fastening portion 11b of the top case 11. Each second fastening member 25 is attached, for example, from the lower side of the bottom case 13 in the vertical direction to the screw hole of the fastening portion 13a of the bottom case 13, the through hole of the second connection portion 23c of the holding member 23, and the screw hole of the control unit holding member 17, thereby fastening and fixing the bottom case 13, the control unit holding member 17, and the holding member 23 together.

[0036] As shown in FIGS. 5 and 6 , the first positive electrode conductor 31P is connected to the positive electrode terminals 21P of six cells 21 in the highest potential column of the cells 21, for example. The second positive electrode conductors 31 are, for example, a total of 12 second positive electrode conductors 31. Each second positive electrode conductor 31 is connected to the positive electrode terminals 21P of six cells 21 in each of the six columns of each battery group 21H, 21L except for the column with the highest potential. The insulating members 32 are, for example, a total of 14 insulating members 32 provided in each column of each battery group 21H, 21L. The first negative electrode conductor 33N is, for example, connected to the negative electrode terminals 21N of six cells 21 in the lowest potential column of the cells 21, for example. The second negative electrode conductors 33 are, for example, a total of 12 second negative electrode conductors 33. Each second negative electrode conductive member 33 is connected to the negative electrode terminals 21N of the six cells 21 in each of the six columns except for the column with the lowest potential in each battery group 21H, 21L.

[0037] 5 and 7, for example, the first positive conductor 31P and each second positive conductor 31 have substantially the same plate-like outer shape. For example, the first positive conductor 31P differs from each second positive conductor 31 in that it includes a terminal portion that is connected to the outside. The first positive conductor 31P and each second positive conductor 31 are formed of a conductive metal material such as copper. The first positive conductor 31P and each second positive conductor 31 include, for example, six positive electrode connectors 31a and five conductive connectors 31b.

[0038] The six positive electrode connecting portions 31a protrude outward in the short-side direction, for example, from positions spaced a predetermined distance apart in the longitudinal direction at one end of the short-side direction of the rectangular, flat-plate-shaped main body of the first positive electrode conductor 31P or each second positive electrode conductor 31. The outer shape of each positive electrode connecting portion 31a is, for example, a semicircular, flat-plate shape that curves so as to be offset from the main body in the thickness direction and then protrudes along the short-side direction. The five conductive connecting portions 31b protrude outward in the short-side direction from between adjacent positive electrode connecting portions 31a in the longitudinal direction of the main body. Each conductive connecting portion 31b has an outer shape of, for example, a rectangular flat plate protruding from the main body in the short-side direction.

[0039] The outer shape of each insulating member 32 is, for example, a flat plate formed by integrating six annular flat members aligned in a row perpendicular to the thickness direction. Each insulating member 32 is made of an electrically insulating material such as resin. Six through-holes 32a are formed in each insulating member 32, penetrating the insulating member 32 in the thickness direction at positions spaced apart by a predetermined distance along the longitudinal central axis. Each through-hole 32a is formed to be larger than the positive electrode connecting portion 31a of each of the first positive electrode conductor 31P and the second positive electrode conductor 31, for example.

[0040] For example, the first negative electrode conductor 33N and each second negative electrode conductor 33 have substantially the same plate-like outer shape. For example, the first negative electrode conductor 33N is different from each second negative electrode conductor 33 in that it has a terminal portion connected to the outside and does not have a conductive connection portion 33b, which will be described later. The first negative electrode conductor 33N and each second negative electrode conductor 33 are formed of a conductive metal material, such as copper. The first negative electrode conductor 33N and each second negative electrode conductor 33 include, for example, six negative electrode connectors 33a and five conductive connectors 33b.

[0041] The outer shape of each negative electrode connecting portion 33a is, for example, a circular flat plate with a through hole 33c formed therethrough in the thickness direction. The through hole 33c of each negative electrode connecting portion 33a is, for example, larger than the through hole 32a of the insulating member 32. The six negative electrode connecting portions 33a are, for example, integrated and lined up in a direction perpendicular to the thickness direction. The outer shape of the six integrated negative electrode connecting portions 33a is, for example, substantially the same as the outer shape of the insulating member 32. For example, the center-to-center spacing of adjacent through holes 33c in the six integrated negative electrode connecting portions 33a is the same as the center-to-center spacing of adjacent through holes 32a in the insulating member 32.

[0042] Each of the five conductive connecting portions 33b protrudes outward in the short-side direction from between adjacent negative electrode connecting portions 33a in the longitudinal direction. The outer shape of each conductive connecting portion 33b is, for example, a rectangular flat plate that protrudes in the thickness direction from between adjacent negative electrode connecting portions 33a and protrudes in the short-side direction via a curved portion 33d that is folded back in a U-shape.

[0043] As shown in Figures 5 and 8, the connecting conductive member 34 is connected, for example, to the negative terminals 21N of six cells 21 in the row on the lowest potential side of the high-potential battery group 21H among the multiple cells 21, and to the positive terminals 21P of six cells 21 in the row on the highest potential side of the low-potential battery group 21L. The outer shape of the connecting conductive member 34 in the cell unit 20 before folding is, for example, a rectangular flat plate. The connecting conductive member 34 includes, for example, six negative electrode connecting portions 34a, six positive electrode connecting portions 34b, and five conductive connecting portions 34c that are integrated with the main body.

[0044] The six negative electrode connecting portions 34a are integrated and provided, for example, at a first end of both ends (first end and second end) in the short direction of the connection conductive member 34. The outer shape of the six integrated negative electrode connecting portions 34a is, for example, the same as the outer shape of the six integrated negative electrode connecting portions 33a in each of the first negative electrode conductive member 33N and the second negative electrode conductive member 33. Each negative electrode connecting portion 34a has a through hole 34d formed therein that is the same as the through hole 33c in each of the first negative electrode conductive member 33N and the second negative electrode conductive member 33. The six positive electrode connecting portions 34b and five conductive connecting portions 34c are provided in an integrated state, for example, at a second end portion in the short direction of the connection conductive member 34. The outer shapes of the integrated six positive electrode connecting portions 34b and five conductive connecting portions 34c are the same as the outer shapes of the integrated main bodies, i.e., the six positive electrode connecting portions 31a and five conductive connecting portions 31b, of the first positive electrode conductor 31P and the second positive electrode conductor 31, for example.

[0045] As shown in Figures 5 and 7, for example, the first positive electrode conductor 31P or the second positive electrode conductor 31 and the first negative electrode conductor 33N or the second negative electrode conductor 33 are connected to each cell 21 in a stacked state with the insulating member 32 sandwiched between them from both sides in the thickness direction. Each positive electrode connecting portion 31a of the first positive electrode conductor 31P or the second positive electrode conductor 31 is inserted into each through hole 32a of the insulating member 32 and each through hole 33c of the first negative electrode conductor 33N or the second negative electrode conductor 33, and is electrically connected to the positive electrode terminal 21P of each cell 21. Each conductive connecting portion 31b of the first positive electrode conductor 31P or the second positive electrode conductor 31 is stacked on the upper side of a portion of the insulating member 32 between adjacent through holes 32a. Each negative electrode connecting portion 33a of the first negative electrode conductor 33N or the second negative electrode conductor 33 is electrically connected to the negative electrode terminal 21N of each cell 21. Each conductive connecting portion 33b of the second negative electrode conductor 33 is stacked on top of each conductive connecting portion 31b of the second positive electrode conductor 31 on the low potential side, and are electrically connected to each other.

[0046] As shown in Figures 5 and 8, for example, the second positive electrode conductive member 31 and the six integrated negative electrode connecting portions 34a of the connecting conductive member 34 are connected to each cell 21 in a stacked state with the insulating member 32 sandwiched between them from both sides in the thickness direction. Each positive electrode connecting portion 31a of the second positive electrode conductive member 31 is inserted into each through hole 32a of the insulating member 32 and each through hole 34d of the connecting conductive member 34, and is electrically connected to the positive electrode terminal 21P of each cell 21. Each conductive connecting portion 31b of the second positive electrode conductive member 31 is stacked on the upper side of a portion of the insulating member 32 between adjacent through holes 32a. Each negative electrode connecting portion 34a of the connecting conductive member 34 is electrically connected to the negative electrode terminal 21N of each cell 21.

[0047] For example, the six positive electrode connection portions 34b and five conductive connection portions 34c integrated into the connecting conductive member 34 and the second negative electrode conductive member 33 are connected to each cell 21 in a stacked state with the insulating member 32 sandwiched between them from both sides in the thickness direction. Each positive electrode connecting portion 34b of the connecting conductive member 34 is inserted into each through-hole 32a of the insulating member 32 and each through-hole 33c of the second negative electrode conductive member 33, and is electrically connected to the positive electrode terminal 21P of each cell 21. Each conductive connecting portion 34c of the connecting conductive member 34 is stacked on the upper side of a portion of the insulating member 32 between adjacent through-holes 32a. Each negative electrode connecting portion 33a of the second negative electrode conductor 33 is electrically connected to the negative electrode terminal 21N of each cell 21. Each conductive connecting portion 33b of the second negative electrode conductor 33 is stacked on top of each conductive connecting portion 31b of the second positive electrode conductor 31 on the low potential side, and are electrically connected to each other.

[0048] As shown in FIGS. 5, 8, and 9, two grooves 34e are formed along the longitudinal direction in the central portion of the connection conductive member 34 in the short-side direction. Each groove 34e is recessed in the thickness direction from the surface of the connection conductive member 34 to form an easily bent portion 34f (or a bending stress concentration portion where bending stress is concentrated) with relatively low bending rigidity. The connection conductive member 34 is folded back, for example, by bending at each easily bent portion 34f at a right angle. By folding back the connection conductive member 34, the positive electrode terminal 21P and the negative electrode terminal 21N on the first end 21a of each cell 21 of the low-potential battery assembly 21L face each other along the axial direction of their central axes.

[0049] 2, 3, and 4, the separating sheet 35 is disposed between the first end 21a of each cell 21 in the low-potential battery assembly 21L and the first end 21a of each cell 21 in the high-potential battery assembly 21H, which are opposed by the folded back connecting conductive members 34. The separating sheet 35 has an outer shape, for example, a rectangular sheet having a front-to-back width greater than the longitudinal width of the connecting conductive members 34 and a top-to-bottom width greater than the longitudinal width of each holding member 23. The separating sheet 35 separates, for example, the first end 21a of each cell 21 in the low-potential battery assembly 21L from the first end 21a of each cell 21 in the high-potential battery assembly 21H. The separable sheet 35 includes, for example, two upper portions 35a protruding upward from both ends in the front-rear direction and two lower portions 35b protruding downward. The two upper portions 35a are inserted into recessed grooves 11c in the lower portion of the top case 11, for example, outward from both ends in the longitudinal direction of the folded-back connecting conductive member 34. The two lower portions 35b are inserted into recessed grooves 13b in the upper portion of the bottom case 13, for example, outward from both ends in the longitudinal direction of the folded-back connecting conductive member 34.

[0050] The process of connecting the first positive electrode conductor 31P, the plurality of second positive electrode conductors 31, the first negative electrode conductor 33N, the plurality of second negative electrode conductors 33, and the connecting conductor 34 to the plurality of cells 21 will be described below. As shown in FIGS. 5, 7 and 8, the conductive members 31P, 31, 33N, 33, and 34 are connected in sequence from the low potential side to the high potential side of the plurality of cells 21, for example. First, the six negative electrode connecting portions 33a of the first negative electrode conductor 33N are connected to the negative electrode terminals 21N of the six cells 21 in the lowest potential side row of the low potential side battery set 21L by a joining process such as laser welding (Step 1). For example, in the case of laser welding, a laser is irradiated from the axial direction along the central axis of each cell 21.

[0051] Next, the insulating member 32 is stacked on the first negative electrode conductor 33N. The insulating member 32 is arranged so that the central axes of each through hole 32a and each through hole 33c of the first negative electrode conductor 33N are aligned with each other, and so that each through hole 32a communicates with each through hole 33c (step 2). Next, the second positive conductor 31 is stacked on the insulating member 32. The six positive electrode connectors 31a of the second positive conductor 31 are inserted into the six through-holes 32a, 33c of the insulating member 32 and the first negative conductor 33N, respectively, and are connected to the positive electrode terminals 21P of the six cells 21 in the lowest potential column of the low potential battery assembly 21L by a joining process such as laser welding. Each of the five conductive connectors 31b of the second positive conductor 31 is disposed between adjacent through-holes 32a in the insulating member 32 (Step 3).

[0052] Next, for six cells 21 in the high potential side column adjacent to the lowest potential side column in the low potential side battery assembly 21L, the six negative electrode connectors 33a of the second negative electrode conductor 33 are connected to the six negative electrode terminals 21N by a joining process such as laser welding. The five conductive connectors 31b of the second negative electrode conductor 33 are connected to the five conductive connectors 31b of the low potential side second positive electrode conductor 31 by a joining process such as laser welding (Step 4). Next, the insulating member 32 is laminated on the second negative electrode conductor 33. The insulating member 32 is arranged such that the central axes of each through hole 32a and each through hole 33c of the second negative electrode conductor 33 are aligned with each other, and each through hole 32a communicates with each through hole 33c (step 5).

[0053] Next, the second positive conductor 31 is laminated on the insulating member 32. The six positive electrode connectors 31a of the second positive conductor 31 are inserted into the six through-holes 32a, 33c of the insulating member 32 and the second negative conductor 33, and are connected to the positive electrode terminals 21P of the six cells 21 in the high-potential column adjacent to the lowest-potential column of the low-potential battery group 21L by a joining process such as laser welding. Each of the five conductive connectors 31b of the second positive conductor 31 is disposed between adjacent through-holes 32a in the insulating member 32 (step 6). Thereafter, in the battery set 21L on the low potential side, the above-described steps 4, 5 and 6 are repeatedly performed four times for the six cells 21 in a row on the higher potential side.

[0054] Next, the above-described steps 4 and 5 are carried out on the six cells 21 in the single column on the highest potential side of the low potential side battery set 21L. Next, the second end of the connection conductive member 34 is laminated on the insulating member 32. The six positive electrode connecting portions 34b of the connection conductive member 34 are inserted into the six through holes 32a, 33c of the insulating member 32 and the second negative electrode conductive member 33, and are connected to the positive electrode terminals 21P of the six cells 21 in the row on the highest potential side of the low potential side battery assembly 21L by a joining process such as laser welding. Each of the five conductive connecting portions 34c of the connection conductive member 34 is disposed between adjacent through holes 32a in the insulating member 32 (Step 7).

[0055] Next, for the six cells 21 in the row on the lowest potential side of the high-potential battery group 21H, the six negative electrode connection portions 34a of the connecting conductive member 34 are connected to the six negative electrode terminals 21N by a joining process such as laser welding (step 8). Next, the insulating member 32 is laminated on the first end of the connecting conductive member 34. The insulating member 32 is arranged so that the central axes of each through hole 32a and each through hole 34d of the connecting conductive member 34 are aligned with each other, and so that each through hole 32a communicates with each through hole 34d (step 9).

[0056] Next, the second positive electrode conductor 31 is laminated on the insulating member 32. The six positive electrode connecting portions 31a of the second positive electrode conductor 31 are inserted into the six through holes 32a, 34d of the insulating member 32 and the connecting conductive member 34, respectively, and are connected to the positive electrode terminals 21P of the six cells 21 in the lowest potential column of the high potential battery assembly 21H by a joining process such as laser welding. Each of the five conductive connecting portions 31b of the second positive electrode conductor 31 is disposed between adjacent through holes 32a in the insulating member 32 (step 10). Thereafter, in the battery set 21H on the high potential side, the above-described steps 4, 5 and 6 are repeatedly performed five times for the six cells 21 in one row on the higher potential side.

[0057] Next, the above-described steps 4 and 5 are carried out on the six cells 21 in the highest potential side column of the high potential side battery set 21H. Next, the first positive conductor 31P is stacked on the insulating member 32. The six positive electrode connectors 31a of the first positive conductor 31P are inserted into the six through-holes 32a, 33c of the insulating member 32 and the second negative conductor 33, respectively, and are connected to the positive electrode terminals 21P of the six cells 21 in the highest potential column of the high-potential battery assembly 21H by a joining process such as laser welding. Each of the five conductive connectors 31b of the first positive conductor 31P is disposed between adjacent through-holes 32a in the insulating member 32 (step 11). This completes the process of connecting the conductive members 31P, 31, 33N, 33, and 34 to the multiple cells 21. Thereafter, by folding back the connecting conductive member 34 at the easy-to-bend portion 34f, the first ends 21a of the multiple cells 21 in the high-potential side battery assembly 21H and the first ends 21a of the multiple cells 21 in the low-potential side battery assembly 21L are positioned to face each other in the axial direction along the central axis.

[0058] As described above, in the battery pack 10 of the embodiment, the first ends 21a where the positive electrode terminals 21P and the negative electrode terminals 21N are provided are oriented in the same direction in the multiple cells 21 of each battery set 21H, 21L, which facilitates joining of the terminals 21P, 21N to the conductive members 31P, 31, 33N, 33, 34. By arranging the multiple cells 21 of each battery set 21H, 21L along the adhesive surface 23A, the positive electrode terminals 21P and the negative electrode terminals 21N of each cell 21 to the conductive members 31P, 31, 33N, 33, 34 can be joined on the same surface, thereby reducing the number of steps required for joining. Since the first end 21a of the cell 21 of the high-potential side battery set 21H and the first end 21a of the multiple cells 21 of the low-potential side battery set 21L are positioned facing each other, it is possible to easily connect each conductive member 31P, 31 on the high-potential side battery set 21H side to each conductive member 33N, 33 on the low-potential side battery set 21L side, or to prevent an increase in the wiring length for connection.

[0059] By providing the connecting conductive member 34 formed integrally with the negative electrode connecting portion 34a and the positive electrode connecting portion 34b, the electrical connection of the high potential side battery set 21H and the low potential side battery set 21L can be easily performed in a consolidated manner, together with the electrical connection of the multiple cells 21 in each battery set 21H, 21L. By providing a bending-easy portion 34f in a part of the connecting conductive member 34, even if the connecting conductive member 34 is bent so as to fold back at the bending-easy portion 34f after the electrical connection of each battery set 21H, 21L is made, it is possible to prevent stress from acting on the electrical connection points between each cell 21 and each conductive member 31P, 31, 33N, 33, 34. Since each cell 21 has a cylindrical outer shape, short-circuiting of potential between adjacent cells 21 can be suppressed compared to other shapes such as a rectangular column.

[0060] (Variation) Modifications of the embodiment will be described below. Note that the same parts as those in the above-described embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified. In the above-described embodiment, a configuration has been described in which the connecting conductive member 34 (battery assembly conductive member) is folded back by the easy-to-bend portion 34f, but this is not limited to this. For example, a configuration may be possible in which there is no folded back portion, and a connecting conductive member is provided for each of the low-potential side battery assembly 21L and the high-potential side battery assembly 21H, and these connecting conductive members are joined or fastened to each other.

[0061] In the above-described embodiment, two grooves 34e are formed along the longitudinal direction of the rectangular, flat-plate-shaped connecting conductive member 34, but this is not limited to this. For example, the width of a portion of the connecting conductive member 34 may be shortened so that the longitudinal length of each groove 34e is shortened. In other words, in the longitudinal direction of the easy-to-bend portion 34f along the width direction of the connecting conductive member 34, the length of the easy-to-bend portion 34f may be relatively shorter than the width of the connecting conductive member 34. FIG. 10 is a perspective view showing the configuration of a cell unit 20A of a battery pack 10 before folding in a first modified example of the embodiment. FIG. 11 is a perspective view showing the configuration of a cell unit 20B after the battery pack 10 in the second modified example of the embodiment has been folded back.

[0062] 10, the connecting conductive member 34A of the first modified example has cutout portions 34g formed at both longitudinal ends thereof. The two upper portions 35a of the separable sheet 35 of the first modified example protrude upward from the cutout portions 34g at both longitudinal ends of the folded connecting conductive member 34A and are inserted into the recessed grooves 11c at the bottom of the top case 11. 11, a through-hole 34h is formed in the longitudinal center of a connecting conductive member 34B of the second modified example. A separable sheet 35A of the second modified example is provided with one upper portion 35c instead of the two upper portions 35a of the embodiment. The one upper portion 35c protrudes upward from the through-hole 34h in the longitudinal center of the folded connecting conductive member 34B and is inserted into a recessed groove 11c in the lower part of the top case 11, for example.

[0063] In the above-described embodiment, the easy-to-bend portions 34f are formed by the grooves 34e of the connection conductive members 34, but this is not limiting. For example, instead of the grooves 34e, the easy-to-bend portions 34f may be formed by a plurality of through holes that penetrate the connection conductive members 34 in the thickness direction. For example, instead of the grooves 34e, the easy-to-bend portions 34f may be formed from a material that is different from the material of the main body of the connection conductive members 34 and has a relatively low rigidity.

[0064] In the above-described embodiment, the multiple cells 21 arranged along the adhesive surface 23A of each holding member 23 may be provided with an insulating member such as an insulating sheet that covers the surface of each cell 21 or a specific cell 21 (e.g., a cylindrical side surface, etc.) in order to prevent, for example, a short circuit between the negative electrode potentials of adjacent cells 21.

[0065] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0066] 10...battery pack, 11...top case, 11a...gripping portion, 11b...fastening portion, 11c...groove, 13...bottom case, 13a...fastening portion, 13b...groove, 15...middle case, 15..., 17...control unit holding member, 19...control unit, 20...cell unit, 21...battery cell (battery cell), 21a...first end, 21b...second end, 21H...high potential side battery set (first battery set), 21L...low potential side battery set (second battery set), 21P...positive terminal, 21N...negative terminal, 22...adhesive, 23...holding member, 23a... Cell holding portion, 23b...first connection portion, 23c...second connection portion, 23A...adhesive surface (mounting surface), 31P...first positive electrode conductive member, 31...second positive electrode conductive member, 32...insulating member, 33N...first negative electrode conductive member, 33...second negative electrode conductive member, 34...connection conductive member (battery assembly conductive member), 34a...negative electrode connection portion (terminal conductive member), 34b...positive electrode connection portion (terminal conductive member), 34c...conductive connection portion, 34e...groove portion, 34f...easy-to-bend portion, 34g...notch portion, 34h...through hole, 24...first fastening member, 25...second fastening member, 35...separation sheet.

Claims

1. a first battery group including a plurality of battery cells; a second battery group including a plurality of battery cells; Equipped with The battery cell is a first end and a second end which are opposite ends in a predetermined direction; a positive electrode terminal and a negative electrode terminal disposed on the first end side; Equipped with the plurality of battery cells in each of the first battery group and the second battery group are arranged along a predetermined mounting surface with the first end and the second end oriented in the same direction, and are electrically connected to each other; the first ends of the plurality of battery cells of the first battery group and the first ends of the plurality of battery cells of the second battery group are disposed in positions facing each other in the predetermined direction; a battery assembly conductive member that electrically connects the positive electrodes of the battery cells of the first battery assembly and the negative electrodes of the battery cells of the second battery assembly, is integrally formed, and has a plurality of folded portions; Equipped with Battery pack.

2. a first battery group including a plurality of battery cells; a second battery group including a plurality of battery cells; Equipped with The battery cell is a first end and a second end which are opposite ends in a predetermined direction; a positive electrode terminal and a negative electrode terminal disposed on the first end side; Equipped with the plurality of battery cells in each of the first battery group and the second battery group are arranged along a predetermined mounting surface with the first end and the second end oriented in the same direction, and are electrically connected to each other; The first ends of the plurality of battery cells of the first battery group and the first ends of the plurality of battery cells of the second battery group are disposed in positions facing each other in the predetermined direction with a separation sheet sandwiched between them, the separation sheet separating the first ends of the plurality of battery cells of the first battery group and the first ends of the plurality of battery cells of the second battery group. Battery pack.

3. a first battery group including a plurality of battery cells; a second battery group including a plurality of battery cells; Equipped with The battery cell is a first end and a second end which are opposite ends in a predetermined direction; a positive electrode terminal and a negative electrode terminal disposed on the first end side; Equipped with the plurality of battery cells in each of the first battery group and the second battery group are arranged along a predetermined mounting surface with the first end and the second end oriented in the same direction, and are electrically connected to each other; the first ends of the plurality of battery cells of the first battery group and the first ends of the plurality of battery cells of the second battery group are disposed in positions facing each other in the predetermined direction; a terminal conductive member that connects the positive electrode terminals or the negative electrode terminals of the plurality of battery cells in at least one of the first battery group and the second battery group; a battery assembly conductive member that is integrally formed with the terminal conductive member and electrically connects the first battery assembly and the second battery assembly; Equipped with Battery pack.

4. A part of the battery assembly conductive member is an easily bendable portion having a relatively low bending rigidity. The battery pack according to claim 3 .

5. In the longitudinal direction of the easy-to-bend portion along the width direction of the battery assembly conductive member, the length of the easy-to-bend portion is relatively smaller than the width of the battery assembly conductive member. The battery pack according to claim 4.

6. The battery cell has a cylindrical outer shape. The battery pack according to any one of claims 1 to 5.

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