Battery pack structure

Abstract

Provided is a battery pack structure advantageous for improving work efficiency in assembling work and disassembling work.　A battery case 14A includes: a case body 20A which accommodates each battery module 12A and has a plurality of accommodation chambers 28 having openings 26 in which the respective battery modules 12A can be individually installed and removed; and a lid body 22A which opens and closes the openings 26 of the plurality of accommodation chambers 28. The case body 20A is provided with a connection member 24A which is connected to electrode terminals 18 of the plurality of battery modules 12A in a state where the battery modules 12A are accommodated in the respective accommodation chambers 28 and the openings 26 are closed off by the lid body 22A, and which connects the battery modules 12A accommodated in the respective accommodation chambers 28 in series.

Description

Battery pack structure

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

[0002] Battery packs are used in electric vehicles, hybrid vehicles, and other electrically powered vehicles that use a motor as a drive source to supply power to the motor. A battery pack includes a battery assembly consisting of multiple battery modules and a battery case consisting of a tray and an upper cover that houses the battery assembly. In many cases, the battery pack is assembled to the vehicle body by detachably attaching the tray to the vehicle body. Each battery module is constructed by housing multiple battery cells connected in series by bus bars for inter-cell connection within a module housing. Each battery module is attached to the bottom wall of the tray via mounting members and bolts and nuts. The electrode terminals of adjacent battery modules are connected in series by bus bars for inter-module connection, forming a battery assembly. The bus bars and electrode terminals are fastened together via nuts.

[0003] JP 2018-163732 A

[0004] Therefore, assembly work during battery pack manufacturing requires tightening bolts and nuts to attach each battery module to the tray and tightening nuts to attach bus bars for connecting the modules together. Furthermore, disassembly work to remove battery cells by disassembling the battery pack for maintenance or recycling or reuse requires removing the battery pack from the vehicle body, and then removing bolts and nuts to remove each battery module from the tray and nuts to remove bus bars for connecting the modules together. Therefore, the work of attaching and detaching battery modules and bus bars for connecting the modules together during battery pack assembly and disassembly requires a great deal of time and effort, and some kind of improvement is needed to improve work efficiency. The present invention has been made in consideration of the above circumstances, and aims to provide a battery pack structure that is advantageous for improving work efficiency during assembly and disassembly.

[0005] In order to achieve the above object, one embodiment of the present invention is a battery pack comprising a plurality of battery modules and a battery case that houses the battery modules, wherein the battery case comprises a case body having a plurality of storage chambers that house each of the battery modules and have openings through which each battery module can be individually inserted and removed, and a lid that opens and closes the openings of the plurality of storage chambers, and the case body is provided with connecting members that are connected to the electrode terminals of the plurality of battery modules with the battery modules housed in each of the plurality of storage chambers and the openings closed by the lid, and that connect the battery modules housed in the plurality of storage chambers in series or in parallel, or that connect the battery modules housed in the plurality of storage chambers in both series and parallel. In one embodiment of the present invention, the battery module has an elongated shape having a width, a height, and a length that is greater than the width and the height, the plurality of storage chambers each have an elongated shape having a width, height, and length corresponding to the battery module, the plurality of storage chambers are formed to store the plurality of battery modules lined up with their lengths parallel, the openings are provided at one end of the length of each of the plurality of storage chambers, and the lid is provided to open and close the plurality of openings. In addition, one embodiment of the present invention is characterized in that the case body has a width that is greater than the width of the battery modules, a height that is greater than the height of the battery modules, and a length that is greater than the width and height of the case body, the case body has a pair of case halves divided in half in the longitudinal direction, the multiple storage chambers are formed in each case half so that the battery modules stored in the storage chambers of each case half are aligned in a straight line in the longitudinal direction of the case body and the battery modules stored in the storage chambers of each case half are stored with their longitudinal directions parallel and aligned in the width direction of the case body, the openings are provided at both ends in the longitudinal direction of the case body, and the lids are provided at both ends in the longitudinal direction of the case body to open and close the multiple openings.In one embodiment of the present invention, the battery pack supplies power to a traction motor of an electric vehicle, and the case body is assembled to a body of the electric vehicle with a length direction of the case body aligned along a width direction of the electric vehicle. In another embodiment of the present invention, the battery module has an elongated shape having a width, a height, and a length that is greater than the width and the height, and each of the plurality of storage chambers has an elongated shape having a width, height, and length corresponding to the battery module, and the plurality of storage chambers are formed to store the plurality of battery modules lined up with their lengths parallel, and the opening is provided at one end of each of the storage chambers in a height direction, and the lid is provided to open and close the plurality of openings. In addition, one embodiment of the present invention is characterized in that the case body has a width that is larger than the width of the battery module, a height that is larger than the height of the battery module, and a length that is larger than the width and height of the case body, and the multiple storage chambers are formed so that, in each half of the longitudinal direction of the case body, the battery modules stored in the storage chambers of each half are arranged in a straight line in the longitudinal direction of the case body, and the battery modules stored in each half are stored with their longitudinal directions parallel and arranged in the width direction of the case body.In one embodiment of the present invention, the battery module has an elongated shape having a width, a height, and a length that is greater than the width and the height, the plurality of storage chambers each having an elongated shape having a width, height, and length corresponding to the battery module, the plurality of storage chambers being formed to store the plurality of battery modules lined up with their longitudinal directions parallel, the openings being provided at one end of the longitudinal directions of the plurality of storage chambers, and the lid body being configured to open and close the plurality of openings individually, and further comprising an open position holding mechanism that holds the lid body in an open position where the openings are open, a closed position holding mechanism that holds the lid body in a closed position where the openings are closed, and a moving mechanism that releases the hold of the lid body by the open position holding mechanism and moves the lid body from the open position to the closed position when the battery module is stored in the storage chamber with the lid body in the open position. In one embodiment of the present invention, the battery module has an elongated shape having a width, a height, and a length that is greater than the width and the height, the plurality of storage chambers each have an elongated shape having a width, height, and length corresponding to the battery module, the plurality of storage chambers are formed to accommodate the plurality of battery modules lined up with their longitudinal directions parallel, the openings are provided at one end of the longitudinal directions of the plurality of storage chambers, and the lid is provided to open and close the plurality of openings individually, and further includes an open position holding mechanism that holds the lid in an open position where the openings are open, a closed position holding mechanism that holds the lid in a closed position where the openings are closed, and a protrusion mechanism that causes the battery module to protrude from the opening when the lid is opened with the battery module accommodated in the storage chamber.

[0006] According to one embodiment of the present invention, the battery modules can be assembled into the battery case by accommodating each battery module in a plurality of chambers and closing the lid. Furthermore, the battery modules can be removed from the battery case by opening the lid and removing each battery module from the plurality of chambers. Therefore, the conventional operations of fastening and loosening bolts and nuts required for installing and removing battery modules and installing and removing bus bars for connecting modules during battery pack assembly and disassembly are no longer necessary. This is advantageous for improving work efficiency during battery pack manufacturing, maintenance and inspection, reuse, and recycling of battery packs. Furthermore, according to one embodiment of the present invention, the battery modules can be installed and removed from the battery case by simply installing and removing them through openings provided at one longitudinal end or one vertical end of the chamber and opening and closing the openings with the lid. This is advantageous for improving work efficiency during battery pack manufacturing, maintenance and inspection, reuse, and recycling of battery packs. Furthermore, according to one embodiment of the present invention, by arranging multiple storage chambers so that battery modules can be lined up in the length and width directions of the case body, it is advantageous to obtain a compact battery pack that can accommodate more battery modules. Furthermore, since the openings of the multiple storage chambers are located at both ends of the length of the case body, when the battery pack is attached to the vehicle body with the length of the case body aligned along the vehicle width direction, battery modules can be attached to and detached from the battery case from both sides of the vehicle width direction while the battery pack is attached to the vehicle body, which is advantageous in improving work efficiency during battery pack maintenance and inspection, reuse, and recycling. Furthermore, according to one embodiment of the present invention, when removing a battery module from the battery case, only the operation of swinging the lid from the closed position to the open position is manually performed, and when inserting a battery module into the battery case, the lid automatically swings from the open position to the closed position, which is advantageous in improving work efficiency during battery pack manufacturing, battery pack maintenance and inspection, reuse, and recycling.Furthermore, according to one embodiment of the present invention, when the lid is moved from the closed position to the open position, the protrusion mechanism causes the battery module to protrude from the opening, making it easy to remove the battery module from the storage chamber, which is more advantageous in terms of improving work efficiency during maintenance and inspection of the battery pack, as well as when reusing and recycling it.

[0007] 11 is a perspective view showing a battery pack structure according to a first embodiment, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is open. 11 is a perspective view showing a battery pack structure according to a first embodiment, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is closed. 11 is a perspective view showing a battery pack structure according to a first embodiment, showing a state in which a battery module is removed from the accommodation chamber and the lid is open. 11 is a front view of a case main body according to the first embodiment. 11 is a cross-sectional view taken along line A-A in FIG. 4. 11 is a cross-sectional view taken along line B-B in FIG. 4. 11 is a perspective view schematically showing a battery module according to the first embodiment. 11 is a perspective view showing a battery pack structure according to a second embodiment, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is open. 11 is a perspective view showing a battery pack structure according to a second embodiment, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is closed. 11 is a perspective view showing a battery pack structure according to a second embodiment, showing a state in which a battery module is removed from the accommodation chamber and the lid is open. 11 is a plan view of a case main body according to the second embodiment. 11 is a cross-sectional view taken along line A-A in FIG. 11 ; a perspective view of a battery module according to a second embodiment; a perspective view of a battery pack structure according to a third embodiment, showing a state in which a battery module is accommodated in a storage chamber and the lid is open; a perspective view of a battery pack structure according to a third embodiment, showing a state in which a battery module is accommodated in a storage chamber and the lid is closed; a perspective view of a battery pack structure according to a third embodiment, showing a state in which a battery module is removed from a storage chamber and the lid is open; a schematic view of a battery pack structure according to a third embodiment, seen from the width direction of the battery case, showing a state in which a battery module is removed from a storage chamber and the lid is open; a schematic view of a battery pack structure according to a third embodiment, seen from the width direction of the battery case, showing a state in which a battery module is being inserted into a storage chamber; a schematic view of a battery pack structure according to a third embodiment, seen from the width direction of the battery case, showing a state in which a battery module is being inserted into a storage chamber and the lid is being moved from the open position to the closed position; 10 is a schematic diagram of a battery pack structure according to a third embodiment, viewed from the width direction of the battery case, showing a state in which a battery module is accommodated in an accommodation chamber and a lid is closed. FIG.1 is a schematic diagram of a battery pack structure according to a third embodiment, viewed from the width direction of the battery case, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is open; FIG. 2 is a schematic diagram of a battery pack structure according to a third embodiment, viewed from the width direction of the battery case, showing a state in which a battery module is being removed from the accommodation chamber; FIG. 3 is a schematic diagram of a battery pack structure according to a fourth embodiment, viewed from the width direction of the battery case, showing a state in which a battery module is accommodated in the accommodation chamber and the lid is closed; and FIG. 4 is a schematic diagram of a battery pack structure according to the fourth embodiment, viewed from the width direction of the battery case, showing a state in which the lid has been moved to the open position and the battery module protrudes from the accommodation chamber.

[0008] First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. The battery pack structure of this embodiment is applied to a battery pack mounted on an electric vehicle powered by a motor alone, such as a hybrid vehicle, or a plug-in hybrid vehicle capable of external charging or external power supply, and supplies power to the motor. As shown in FIG. 1 , a battery pack 10A includes multiple battery modules 12A and a battery case 14A that houses the battery modules 12A. As shown in FIG. 7 , the battery module 12A is configured by multiple battery cells 16 (eight battery cells 16 in this example) having the same shape and size and a thickness, width, and height, housed in a module housing (not shown) in a stacked state with their width and height aligned. Adjacent battery cells 16 have their positive and negative electrode terminals connected in series via a bus bar (not shown) for connecting the battery cells. The bus bars for connecting the battery cells are connected to the electrode terminals in the same manner as in the past, by fastening nuts to the male threads of the electrode terminals that are inserted into the screw insertion holes of the bus bars. Note that various conventionally known module housings and bus bars can be used.

[0009] As shown in Figure 7, in this embodiment, the battery module 12A has an elongated plate shape having a width W, a height H, and a length L that is greater than the width W and height H. The width and height directions of the multiple battery cells 16 that make up the battery module 12A coincide with the width W and height H directions of the battery module 12A, and the stacking direction of the multiple battery cells 16 coincides with the length L direction of the battery module 12A. Furthermore, both end faces of the multiple battery cells 16 in the width W direction are located on the same plane, and both end faces in the height H direction are located on the same plane. The battery module 12A has side surfaces 1202 on both sides in the width W direction, an upper surface 1204 and a lower surface 1206 located above and below in the height H direction, and a pair of end faces 1208 located at both ends in the length L direction.

[0010] One end face 1208 of the battery module 12A in the length L direction is provided with a pair of electrode terminals 18 consisting of a positive electrode terminal 18A and a negative electrode terminal 18B of the battery module 12A. The positive electrode terminal 18A of the battery module 12A is connected via a connecting member (not shown) to the positive electrode terminal 18A of the battery cell 16 located at one end in the stacking direction of the multiple battery cells 16, and the negative electrode terminal 18B of the battery module 12A is connected via a connecting member (not shown) to the negative electrode terminal 18B of the battery cell 16 located at the other end in the stacking direction of the multiple battery cells 16. In this embodiment, the pair of electrode terminals 18 are formed at the same height and near both sides in the width direction W of one of the pair of end faces 1208 located at both ends in the length L direction.

[0011] As shown in FIGS. 1 and 3 , the battery case 14A includes a case body 20A, a lid 22A, and a connecting member 24A (see FIGS. 4 and 6 ). The battery case 14A is equivalent to a conventional tray and top cover. Like a conventional tray, the case body 20A of the battery case 14A is detachably attached to an appropriate location on the vehicle body, such as multiple cross members supporting the battery pack, via brackets (not shown). In this embodiment, the case body 20A has a width greater than the width of the battery modules 12A, a height greater than the height of the battery modules 12A, and a length greater than the width and height of the case body 20A. The case body 20A is rectangular and made of an insulating synthetic resin material. The case body 20A houses each battery module 12A and has multiple storage chambers 28 with openings 26 through which each battery module 12A can be individually inserted and removed. As shown in FIGS. 5 and 6 , in this embodiment, the case body 20A includes a pair of case halves 30 divided in half lengthwise. A plurality of storage chambers 28 are formed in each of the pair of case halves 30, and openings 26 are formed in the storage chambers 28 at both ends of the case body 20A in the longitudinal direction. Specifically, the plurality of storage chambers 28 are formed in each case half 30 so that the battery modules 12A housed in the storage chambers 28 of each case half 30 are aligned linearly along the longitudinal direction of the case body 20A and arranged in the width direction of the case body 20A with their lengths parallel to each other. The openings 26 are provided at both ends of the longitudinal direction of the case body 20A. Lids are provided at both ends of the longitudinal direction of the case body 20A to open and close the plurality of openings 26. In other words, by arranging multiple storage chambers 28 so that the battery modules 12A can be stored side by side in the length and width directions of the case body 20A, it is advantageous to obtain a compact battery pack 10A that can store more battery modules 12A.

[0012] Each of the multiple storage chambers 28 has an elongated shape with a width, height, and length corresponding to the width W, height H, and length L of the battery module 12A. The multiple storage chambers 28 are arranged so that their longitudinal directions are parallel to one another, and both ends of each of the multiple storage chambers 28 in the longitudinal direction and both ends of each of the multiple storage chambers 28 in the height direction are located on a single plane. Therefore, when battery modules 12A are housed in the multiple storage chambers 28 of each case half 30, the multiple storage chambers 28 are arranged so that the side surfaces 1202 on both sides of each battery module 12A in the width W direction, the upper and lower surfaces 1204 and 1206 located above and below in the height H direction, and the pair of end surfaces 1208 located at both ends of each battery module 12A in the longitudinal direction are all flush with each other.

[0013] 4 and 5 , the case body 20A includes an upper wall 2002 and a lower wall 2004 that face each other in the vertical direction, a pair of side walls 2006 that connect the upper wall 2002 and the lower wall 2004 on both sides in the width direction, and an intermediate wall 2008 that is located at the longitudinal center of the upper wall 2002, the lower wall 2004, and the pair of side walls 2006 and divides the case body 20A at the longitudinal center. Furthermore, the case body 20A includes a plurality of partition walls 2010 that extend along the longitudinal direction of the case body 20A between the pair of side walls 2006, parallel to the side walls 2006, and are spaced apart in the width direction of the case body 20A. Each storage chamber 28 is defined by a space (partitioned space) surrounded by the upper wall 2002, the lower wall 2004, the pair of side walls 2006, the plurality of partition walls 2010, and the intermediate wall 2008.

[0014] As shown in Figures 4 and 5 , the ends of the upper wall 2002, the lower wall 2004, and the pair of side walls 2006 located at both ends in the longitudinal direction of the case body 20A form a rectangular frame-shaped case body end face 2014 extending on the same plane, and the openings 26 of each storage chamber 28 are located inside the case body end face 2014. In this embodiment, each partition wall 2010 has both ends in the vertical direction connected to the upper wall 2002 and the lower wall 2004, one end in the extending direction connected to the intermediate wall 2008, and the other end in the extending direction forms a notch 2012 located at a position displaced closer to the intermediate wall 2008 than the case body end face 2014, as shown in Figure 5 . This allows the battery module 12A stored in each storage chamber 28 to be easily removed from the storage chamber 28 through the opening 26 by inserting a finger through the space secured by the notch 2012 to grasp the battery module 12A stored in the storage chamber 28.

[0015] As shown in FIGS. 1 and 2 , the lids 22A are configured to open and close the openings 26 provided at one longitudinal end of the multiple storage chambers 28, i.e., to open and close the multiple openings 26 located on the case body end surface 2014. While multiple lids 22A may be provided to individually open and close the openings 26 of the multiple storage chambers 28, in this embodiment, a single lid 22A is provided for each of the pair of case halves 30, simplifying the structure and reducing costs of the battery case 14A. Each lid 22A has a rectangular plate shape with the same width and height as the case body 20A and is made of an insulating synthetic resin material. One widthwise side of each lid 22A is supported by multiple hinges 32 on one side wall 2006 of the case body 20A so that it can swing about an axis extending in the vertical direction. Each cover 22A swings between an open position in which the openings 26 are open as shown in FIG. 1 and a closed position in which the openings 26 are closed as shown in FIG.

[0016] As shown in Fig. 1, a bulge 2202 is formed on the other widthwise side of the lid 22A, and a screw insertion hole 2204 is provided in this bulge 2202. Furthermore, a bulge 2016 corresponding to the bulge 2202 of the lid 22A is formed on the case main body end surface 2014 at a location corresponding to the bulge 2202 of the lid 22A, and a screw hole 2018 corresponding to the screw insertion hole 2204 is provided in this bulge 2016. As shown in Fig. 2, when the lid 22A is in the closed position, the bolt 34 is threadedly engaged with the screw hole 2018 of the case main body 20A through the screw insertion hole 2204 of the lid 22A, thereby holding the lid 22A in the closed position. As shown in FIG. 1, an annular sealing member 36 is attached along the outer periphery of the inner surface of the lid body 22A facing the multiple openings 26, and when the lid body 22A is in the closed position, the sealing member 36 is pressed against the end face 2014 of the case body, thereby keeping each storage chamber 28 liquid-tight from the outside of the battery case 14A and preventing the intrusion of water and dust from the outside.

[0017] 1 , a plurality of biasing members 38 are provided on the inner surface of the lid 22A, and when battery modules 12A are housed in each of the plurality of storage chambers 28 and the openings 26 are closed by the lid 22A, the biasing members 38 elastically contact the battery modules 12A, thereby biasing the battery modules 12A toward the intermediate wall 2008. In this manner, the biasing members 38 bias the battery modules 12A toward the intermediate wall 2008, so that the battery modules 12A are housed in the storage chambers 28 without rattling in the longitudinal direction, and the electrode terminals 18 of the battery modules 12A are pressed against the connecting members 24A, thereby ensuring reliable electrical connection, as will be described later. Note that the contact portion 2402 of the connecting member 24A provided on the intermediate wall 2008 (described later) may be formed of an elastic leaf spring or coil spring made of a conductive material to bias the contact portion 2402 of the connecting member 24A toward the electrode terminal 18 of the battery module 12A, in which case the biasing member 38 provided on the lid 22A can be omitted. That is, the biasing member 38 may be provided on the lid 22A or on the intermediate wall 2008. Alternatively, the biasing member 38 may be omitted by increasing the dimensional accuracy of the storage chamber 28.

[0018] As shown in FIGS. 4 and 6 , the connecting member 24A is provided on the intermediate wall 2008 of the case body 20A and is connected to the electrode terminals 18 of the battery modules 12A when the battery modules 12A are housed in the respective storage chambers 28 and the openings 26 are closed by the lids 22A. This electrically connects the battery modules 12A housed in the respective storage chambers 28. Specifically, the connecting member 24A is connected to the electrode terminals 18 of the battery modules 12A when the battery modules 12A are housed in the respective storage chambers 28 and the openings 26 are closed by the lids 22A. This connects the battery modules 12A housed in the respective storage chambers 28 in series, in parallel, or in both series and parallel. In this embodiment, the connecting member 24A contacts the positive electrode terminal 18A and the negative electrode terminal 18B of adjacent battery modules 12A, thereby electrically connecting the electrode terminals to each other, thereby connecting the battery modules 12A in series. The connecting member 24A is made of a conductive metal strip.

[0019] 4 and 6 , the connecting member 24A is provided at a location on the intermediate wall 2008 that forms each storage chamber 28, and includes a pair of contact portions 2402 that come into contact with the positive electrode terminal 18A and the negative electrode terminal 18B of the battery module 12A stored in the storage chamber 28, and a non-contact portion 2404 that is embedded in the partition wall 2010 and connects the positive electrode terminal 18A and the negative electrode terminal 18B of adjacent storage chambers 28. The contact portions 2402 are provided on the surface of the intermediate wall 2008 that faces the electrode terminals 18 of the battery modules 12A. In this embodiment, the connection member 24A is described as having the contact portion 2402 in contact with the electrode terminals 18 of the battery modules 12A to connect the battery modules 12A in series, but the connection member 24A may have the contact portion 2402 in contact with the electrode terminals 18 of the battery modules 12A to connect the battery modules 12A in parallel, or may connect the battery modules 12A in series and in parallel, and the configuration of the connection member 24 is not limited to this embodiment. For example, the contact portion 2402 of the connection member 24A may be made of a plate-shaped metal material, and the non-contact portion 2404 may be made of an electric wire whose conductor is coated with an insulator or a bare wire whose conductor is not coated with an insulator.

[0020] 6 , a pair of output connection members 40 are provided on the surface of the intermediate wall 2008 facing the positive electrode terminal 18A and the negative electrode terminal 18B of the battery modules 12A located at both ends of the plurality of battery modules 12A connected in series, and the pair of output connection members 40 are connected to a pair of output terminals (not shown) of the battery pack 10A via electric wires, and the pair of output terminals (not shown) are connected to an inverter and a charging device on the vehicle side via a power cable. The pair of output connection members 40 are formed of elastic leaf springs or coil springs made of plate-shaped metal material or conductive material, similar to the contact portions 2402 described above.

[0021] Next, the assembly of the battery module 12A into the battery case 14A will be described. Assume that multiple battery modules 12A have been prepared in advance, and the battery pack 10A has been removed from the vehicle body. As shown in Fig. 3 , the lid 22A is positioned in the open position relative to the case body 20A, and the height H and width W of the battery module 12A are aligned with the height and width of the case body 20A. The battery module 12A is then inserted into the storage chamber 28 through the opening 26 with one end face 1208, on which the pair of electrode terminals 18 are provided, facing forward.

[0022] This process is repeated until all of the storage chambers 28 are filled with battery modules 12A. Once all of the storage chambers 28 have battery modules 12A, as shown in FIG. 1 , the lid 22A of each case half 30 is moved to the closed position to close the opening 26, as shown in FIG. 2 , and the bolts 34 are threaded through the bolt insertion holes of the lid 22A and into the screw holes 2018 of the case body 20A to secure the lid 22A in the closed position. By securing the lid 22A in the closed position, each battery module 12A is attached to the battery case 14A, completing the battery pack 10A. The completed battery pack 10A can then be removably mounted to a vehicle body. With the battery modules 12A housed in each of the storage chambers 28 and the openings 26 closed by the lids 22A, the pair of electrode terminals 18 of each battery module 12A are connected to the connecting members 24A, thereby connecting the multiple battery modules 12A in series. The positive electrode terminal 18A and the negative electrode terminal 18B of the battery module 12A located at both ends of each battery module 12A are connected to a pair of output connection members 40, so that the multiple battery modules 12A connected in series function as a battery pack.

[0023] Next, the removal of the battery module 12A from the battery case 14A will be described. This removal is performed with the battery pack 10A removed from the vehicle body. First, as shown in FIG. 2 , the bolts 34 securing the lid 22A are removed from the screw holes 2018 of the case body 20A via the screw insertion holes 2204 of the lid 22A. As shown in FIG. 1 , the lid 22A is placed in the open position, and the battery module 12A accommodated in each accommodation chamber 28 is grasped by inserting fingers through the spaces secured by the notches 2012 formed in each partition wall 2010, and the battery module 12A is removed from the accommodation chamber 28 through the opening 26.

[0024] According to this embodiment, the battery modules 12A can be assembled to the battery case 14A by accommodating each battery module 12A in a plurality of accommodation chambers 28 and closing the lid 22A, and the battery modules 12A can be removed from the battery case 14A by opening the lid 22A and removing each battery module 12A from the plurality of accommodation chambers 28. Therefore, in the assembly process for manufacturing the battery pack 10A, the conventionally required work of fastening bolts and nuts at multiple locations to attach each battery module 12A to a tray and the work of fastening nuts at multiple locations to attach bus bars for connecting modules are no longer necessary, which is advantageous in improving work efficiency during the manufacturing of the battery pack 10A. Furthermore, when disassembling the battery pack 10A to remove the battery cells 16 for maintenance, recycling, or reuse of the battery pack 10A, the conventionally required work of removing bolts and nuts at multiple locations to remove each battery module 12A from the tray and the work of removing nuts at multiple locations to remove the bus bars that connect the modules together are no longer necessary, which is advantageous in improving work efficiency during maintenance and inspection of the battery pack 10A, reuse, and recycling.

[0025] Furthermore, in this embodiment, the lid 22A is provided to open and close the opening 26 provided at one end in the longitudinal direction of the plurality of storage chambers 28. Therefore, the battery module 12A can be attached to and detached from the battery case 14A by the simple operation of inserting and detaching the elongated battery module 12A through the opening 26 provided at one end in the longitudinal direction of the elongated storage chamber 28 having a width, height, and length corresponding to the battery module 12A, and opening and closing the opening 26 with the lid 22A. This is advantageous in terms of improving work efficiency during the manufacture of the battery pack 10A and during the maintenance and inspection, reuse, and recycling of the battery pack 10A. Furthermore, since the openings 26 of the multiple storage chambers 28 are located at both ends in the longitudinal direction of the case body 20A, when the battery pack 10A is attached to the vehicle body with the longitudinal direction of the case body 20A aligned with the vehicle width direction, the battery module 12A can be attached to and detached from the battery case 14A from both sides in the vehicle width direction without removing the battery pack 10A from the vehicle body, which is more advantageous in terms of improving work efficiency during maintenance and inspection of the battery pack 10A and when reusing or recycling it.

[0026] Second Embodiment Next, a second embodiment will be described with reference to Figures 8 to 14. In the following embodiments, parts and components similar to those of the first embodiment are denoted by the same reference numerals, and their description will be omitted. The following description will focus on the differences. A battery pack 10B of the second embodiment differs from the first embodiment in that a plurality of openings 26 are provided at one end of the case body 20B in the height direction, a lid 22B is provided for opening and closing the plurality of openings 26, a pair of electrode terminals 18 of the battery module 12B are provided at one end of the battery module 12B in the height direction H, and a connecting member 24B is provided on the bottom wall 2024 of the case body 20B.

[0027] 14 , the battery module 12B is configured by containing a plurality of battery cells 16 in a module housing (not shown) in a stacked state in the thickness direction with their width and height directions aligned, as in the first embodiment, and adjacent battery cells 16 are connected in series via bus bars (not shown) for connecting the battery cells. In the second embodiment, a pair of electrode terminals 18 consisting of a positive electrode terminal 18A and a negative electrode terminal 18B of the battery module 12B is provided on the underside 1206 of the battery module 12B, and the pair of electrode terminals 18 are formed at the same positions in the width W direction near both ends in the length L direction of the underside 1206 of the battery module 12B.

[0028] As shown in Figures 8 and 10, the battery case 14B includes a case body 20B, a lid 22B, and a connecting member 24B (see Figures 11 and 13). In the second embodiment, the case body 20B also has a width greater than the width of the battery modules 12B, a height greater than the height of the battery modules 12B, and a length greater than the width and height of the case body 20B. The case body 20B is rectangular and made of a synthetic resin material. The case body 20B houses the battery modules 12B and has multiple storage chambers 28 with openings 26 through which the battery modules 12B can be individually inserted and removed. In the second embodiment, the openings 26 for the storage chambers 28 are formed at one end (top end) of the case body 20B in the height direction.

[0029] Each of the multiple storage chambers 28 has an elongated shape with a width, height, and length corresponding to the width W, height H, and length L of the battery module 12B. The multiple storage chambers 28 are arranged so that their longitudinal directions are parallel to one another, and both ends of each of the multiple storage chambers 28 in the longitudinal direction and both ends of each of the multiple storage chambers 28 in the height direction are located on a single plane. Therefore, when a battery module 12B is housed in each of the multiple storage chambers 28, the side surfaces 1202 on both sides of each battery module 12B in the width W direction, the upper surface 1204 and the lower surface 1206 located above and below in the height H direction, and the pair of end surfaces 1208 located at both ends of each battery module 12B in the longitudinal direction are all located on the same plane.

[0030] 11 , 12 , and 13 , the case body 20B includes a pair of end walls 2020 facing each other in the longitudinal direction, a pair of side walls 2022 connecting both sides of the pair of end walls 2020 in the width direction, and a bottom wall 2024 connecting the pair of end walls 2020 to the lower ends of the pair of side walls 2022. Furthermore, the case body 20B includes a single first partition wall 2026 and a plurality (six) of second partition walls 2028. The first partition wall 2026 extends along the width direction of the case body 20B in parallel with the pair of end walls 2020 in the center between the pair of end walls 2020, with both ends in the extension direction connected to the pair of side walls 2022 and a bottom end connected to the bottom wall 2024. The multiple second partitions 2028 extend along the length of the case body 20B between a pair of side walls 2022, parallel to the side walls 2022, and are formed at intervals in the width direction of the case body 20B, with one end of each of them connected to the first partition 2026, the other end connected to one or the other of the end walls 2020, and their lower ends connected to the lower wall 2024.

[0031] Each storage chamber 28 is formed as an upwardly open space (partitioned space) surrounded by a pair of end walls 2020, a pair of side walls 2022, a first partition 2026, a second partition 2028, and a bottom wall 2024. In the second embodiment, four storage chambers 28 are provided facing each other in the longitudinal direction of the case body 20B, with the first partition 2026 sandwiched between them. In other words, the multiple storage chambers 28 are formed in each longitudinal half of the case body 20B so that the battery modules 12B housed in the storage chambers 28 of each half are aligned linearly in the longitudinal direction of the case body 20B and aligned in the width direction of the case body 20B with their longitudinal directions parallel to each other. In other words, arranging the multiple storage chambers 28 so that the battery modules 12B can be aligned in both the longitudinal and width directions of the case body 20B is advantageous in obtaining a compact battery pack 10B that can house a greater number of battery modules 12B. At the upper end of the case body 20B, the upper ends of the pair of end walls 2020 and the upper ends of the pair of side walls 2022 form a rectangular frame-shaped case body end face 2032 that extends on the same plane, and the openings 26 of each storage chamber 28 are located inside the case body end face 2032. As shown in FIGS. 12 and 13 , the upper ends of the first partition wall 2026 and the second partition wall 2028 are provided with notches 2030, and the upper ends of the first partition wall 2026 and the second partition wall 2028 are located at positions displaced closer to the lower wall 2024 than the case body end face 2014. This allows the battery module 12B accommodated in each storage chamber 28 to be easily removed from the storage chamber 28 through the openings 26 by inserting a finger through the space secured by the notches 2030 to grasp the battery module 12B.

[0032] Although multiple lids 22B may be provided so that the openings 26 of the multiple storage chambers 28 can be opened and closed individually, in this embodiment, a single lid 22A is provided so that the openings 26 of the multiple storage chambers 28 can be opened and closed simultaneously, thereby simplifying the structure and reducing costs of the battery case 14B. That is, as shown in FIGS. 8 and 9 , the lid 22B is provided to open and close the multiple openings 26 provided at one end of the multiple storage chambers 28 in the height direction, i.e., to open and close all of the openings 26 located on the case body end surface 2032. The lids 22B are rectangular plates with the same length and width as the case body 20B, and each lid 22B is made of an insulating synthetic resin material. One widthwise side of the lid 22B is supported by one side wall 2022 of the case body 20B via multiple hinges (not shown) so as to be swingable about an axis extending in the length direction of the case body 20B. The cover 22B swings between an open position in which the openings 26 are open as shown in FIG. 8 and a closed position in which the openings 26 are closed as shown in FIG.

[0033] As shown in Fig. 8, a bulge 2206 is formed on the other widthwise side of the lid 22B, and a screw insertion hole 2208 is provided in this bulge 2206. Furthermore, a bulge 2034 corresponding to the bulge 2206 of the lid 22B is formed on the case main body end surface 2032 at a location corresponding to the bulge 2206 of the lid 22B, and a screw hole 2036 corresponding to the screw insertion hole 2208 is provided in this bulge 2034. As shown in Fig. 9, when the lid 22B is in the closed position, the bolt 34 is threadedly engaged with the screw hole 2036 of the case main body 20B through the screw insertion hole 2208 of the lid 22B, thereby holding the lid 22B in the closed position. As shown in FIG. 8, similarly to the first embodiment, an annular sealing member 36 is attached along the outer periphery of the inner surface of the lid body 22B facing the multiple openings 26, and when the lid body 22B is in the closed position, the sealing member 36 is pressed against the end face 2032 of the case body, thereby keeping each storage chamber 28 liquid-tight from the outside of the battery case 14B and preventing the intrusion of water and dust from the outside.

[0034] In addition, a plurality of biasing members 38 are provided on the inner surface of the lid 22B, and when battery modules 12B are housed in each of the plurality of storage chambers 28 and the openings 26 are closed by the lid 22B, the biasing members 38 elastically contact the battery modules 12B, thereby biasing the battery modules 12B toward the bottom wall 2024. In this manner, the biasing members 38 bias the battery modules 12B toward the bottom wall 2024, so that the battery modules 12B are housed in the storage chambers 28 without rattling in the height direction, and the electrode terminals 18 of the battery modules 12B are pressed against the connecting members 24B, as will be described later, to ensure reliable electrical connection. The contact portion 2402 of the connecting member 24B provided on the bottom wall 2024 (described later) may be formed of an elastic leaf spring or coil spring made of a conductive material to bias the contact portion 2402 of the connecting member 24B toward the electrode terminal 18 of the battery module 12B, in which case the biasing member 38 provided on the lid 22B can be omitted. That is, the biasing member 38 may be provided on the lid 22B or on the bottom wall 2024. Alternatively, the biasing member 38 may be omitted by increasing the dimensional accuracy of the storage chamber 28.

[0035] 11 and 13 , similar to the first embodiment, the connecting member 24B is provided on the bottom wall 2024 of the case body 20B and is connected to the electrode terminals 18 of the plurality of battery modules 12B in a state in which the battery modules 12B are housed in the respective storage chambers 28 and the openings 26 are closed by the lids 22B. Similar to the first embodiment, the connecting member 24B contacts the positive electrode terminal 18A and the negative electrode terminal 18B of adjacent battery modules 12B to electrically connect the electrode terminals, thereby connecting the battery modules 12B in series, and the connecting member 24B is made of a conductive metal strip. The connecting member 24B is provided at a location on the bottom wall 2024 that forms each storage chamber 28, and includes a pair of contact portions 2402 that come into contact with the positive and negative electrode terminals 18B of the battery modules 12B stored in the storage chamber 28, and a non-contact portion 2404 that is embedded in the first partition wall 2026 and the end wall 2020 and connects the positive electrode terminal 18A and the negative electrode terminal 18B of adjacent storage chambers 28. The contact portions 2402 are provided on the surface of the bottom wall 2024 that faces the electrode terminals 18 of the battery modules 12B. As in the first embodiment, the configuration of the connecting member 24B is not limited as long as the contact portions 2402 come into contact with the electrode terminals 18 of the battery modules 12B to connect the battery modules 12B in series. As shown in FIGS. 11 and 13 , a pair of output connection members 40 are provided on the surface of the lower wall 2024 facing the positive electrode terminal 18A and the negative electrode terminal 18B of the battery modules 12B located at both ends of the plurality of battery modules 12B connected in series, and the pair of output connection members 40 are connected to a pair of output terminals (not shown) of the battery pack 10B via electric wires, respectively, as in the first embodiment.

[0036] Next, the assembly of the battery module 12B into the battery case 14B will be described. Assume that multiple battery modules 12B have been prepared in advance, and the battery pack 10B has been removed from the vehicle body. As shown in Fig. 10 , the lid 22B is positioned in the open position relative to the case body 20B, and the length L and width W of the battery module 12B are aligned with the length L and width W of the case body 20B. The battery module 12B is then inserted into the storage chamber 28 through the opening 26 with the bottom surface 1206, on which the pair of electrode terminals 18 are provided, facing downward.

[0037] This process is repeated until all of the storage chambers 28 have battery modules 12B housed therein. Once all of the storage chambers 28 have battery modules 12B housed therein, as shown in FIG. 8 , the lid 22B is moved to the closed position to close the openings 26, and the bolts 34 are threaded through the screw insertion holes 2208 of the lid 22B and into the screw holes 2036 of the case body 20B to secure the lid 22B in the closed position. When the lid 22B is secured in the closed position, each battery module 12B is attached to the battery case 14B, completing the battery pack 10B. The completed battery pack 10B is then removably attached to a vehicle body. With the battery modules 12B housed in each of the storage chambers 28 and the openings 26 closed by the lids 22B, the pair of electrode terminals 18 of each battery module 12B are connected to the connecting members 24B, thereby connecting the plurality of battery modules 12B in series. The positive electrode terminal 18A and the negative electrode terminal 18B of the battery module 12B located at both ends of each battery module 12B are connected to a pair of output connection members 40, so that the multiple battery modules 12B connected in series function as a battery pack.

[0038] Next, the removal of the battery modules 12B from the battery case 14B will be described. This removal is performed with the battery pack 10B removed from the vehicle body. First, as shown in FIG. 9 , the bolts 34 securing the lid 22B are removed from the screw holes 2036 of the case body 20B via the screw insertion holes 2208 of the lid 22B. Next, as shown in FIG. 8 , the lid 22B is placed in the open position, and the battery modules 12B accommodated in each of the accommodation chambers 28 are grasped by inserting fingers through the spaces provided by the cutouts 2030 formed in the first and second partition walls 2026 and 2028, and the battery modules 12B are removed from the accommodation chambers 28 through the openings 26.

[0039] As in the first embodiment, the second embodiment allows the battery modules 12B to be assembled into the battery case 14B by accommodating each battery module 12B in a plurality of storage chambers 28 and closing the lid 22B. Furthermore, the battery modules 12B can be removed from the battery case 14B by opening the lid 22B and removing each battery module 12B from the plurality of storage chambers 28. This is advantageous in improving work efficiency during the manufacture of the battery pack 10B, or during maintenance, inspection, reuse, and recycling of the battery pack 10B. Furthermore, in the second embodiment, the lid 22B is configured to open and close the opening 26 provided at one end of the plurality of storage chambers 28 in the height direction. Therefore, the battery module 12B, which has an elongated shape, can be attached to and detached from the battery case 14B by the simple operation of inserting and detaching the battery module 12B through the opening 26 provided at one end in the height direction of the elongated storage chamber 28, which has a width, height, and length corresponding to the battery module 12B, and opening and closing the opening 26 with the lid 22B. This is advantageous in terms of improving work efficiency during the manufacture of the battery pack 10B and during the maintenance and inspection, reuse, and recycling of the battery pack 10B.

[0040] Third Embodiment Next, a battery pack 10C according to a third embodiment will be described with reference to Figures 15 to 23. The third embodiment is a modification of the first embodiment, in which the lid 22C is automatically swung from the open position to the closed position when the battery module 12A is housed in the battery case 14C, thereby simplifying the opening and closing of the lid. In the third embodiment, the structure of the battery module 12A, the structure of the case body 20C, the structure of the housing chamber 28 provided in the case body 20C, and the structure of the connecting member 24B provided in the case body 20C are also substantially the same as those in the first embodiment.

[0041] 15, in the third embodiment, the cover 22C is provided to individually open and close the plurality of openings 26. Furthermore, in the third embodiment, an open position holding mechanism 42, a closed position holding mechanism 44, and a movement mechanism 46 are provided, as shown in FIG.

[0042] The closed position retention mechanism 44 retains the lid body 22C in the closed position, closing the opening 26. The closed position retention mechanism 44 includes a spring member 48, such as a helical spring or a torsion coil spring. Specifically, as shown in FIGS. 15 and 17 , each lid body 22C includes a rectangular main body plate portion 2210 sized to close the opening 26, and as shown in FIG. 16 , an attachment plate portion 2212 provided at one end in the height direction of the main body plate portion 2210 and having a shaft insertion hole 2214 formed therethrough. As shown in FIG. 18 , the lower end of the attachment plate portion 2212 has a cylindrical surface. A shaft 2216 supported by the case body 20C is inserted into the shaft insertion hole 2214 of each lid body 22C, allowing each lid body 22C to swing around the shaft 2216. The spring members 48 are wound around support shafts 2216 on both sides of the mounting plate portion 2212 of each lid body 22C, and urge each lid body 22C to a closed position that closes the opening 26, as shown in FIG.

[0043] The open position retention mechanism 42 retains the lid body 22C in the open position in which the opening 26 is open. In this embodiment, the open position retention mechanism 42 includes a stopper member 50. Specifically, as shown in FIG. 18 , support walls 2040 are provided on the bottom wall 2004 of the case body 20C at locations corresponding to the respective storage chambers 28, protruding downward, and the stopper member 50 is supported by the support walls 2040. The stopper member 50 includes a cylindrical body 5002 supported in a support hole of the support wall 2040 so as to be movable in the length direction of the storage chamber 28, a compression coil spring 5004 inserted inside the cylindrical body 5002, and a stopper pin 5006 supported so as to be movable inside the cylindrical body 5002 and constantly biased in a protruding direction by the compression coil spring 5004, and the tip of the stopper pin 5006 is formed into a spherical surface.

[0044] 18 shows the position where the stopper pin 5006 is most protruded, and in the protruding position of the stopper pin 5006, the tip of the stopper pin 5006 is located below the lower end of the mounting plate portion 2212 of the lid body 22C and engages with the lower end of the mounting plate portion 2212 from below, maintaining the lid body 22C in the open position. When the stopper pin 5006 is in the protruding position, a pressing force acts on the stopper pin 5006, compressing the compression coil spring 5004, and therefore the stopper pin 5006 can be retracted from the protruding position.

[0045] When the battery module 12A is accommodated in the accommodation chamber 28 with the lid body 22C in the open position, the movement mechanism 46 releases the lid body 22C from the open position holding mechanism 42 and moves the lid body 22C from the open position to the closed position. The movement mechanism 46 includes a stopper member 50, a lifting member 52, a compression coil spring 54, a rack 56, a link 58, a pinion 60, and a one-way clutch 62.

[0046] Specifically, the lifting members 52 are provided on the bottom wall 2004 of the case body 20C at locations that correspond to the locations near the intermediate wall 2008 of each storage chamber 28 so as to extend into and retract from the storage chamber 28. The lifting members 52 are guided by guides (not shown) provided on the bottom wall 2004 of the case body 20C along the height direction of the storage chamber 28 between an elevated position where they extend into the storage chamber 28 as shown in FIGS. 18 and 19 and a lowered position where they are positioned on the underside of the storage chamber 28 as shown in FIGS. 21 and 22 , and the compression coil springs 54 bias the lifting members 52 to always remain in the elevated position. As shown in FIGS. 21 and 22 , the upper portion of the lifting members 52 is provided with an inclined guide surface 5202 that engages with the corner of the lower tip of the battery module 12A when the battery module 12A is stored in the storage chamber 28, allowing the lifting members 52 to descend from the elevated position to the lowered position. The rack 56 is provided extending vertically at a location of the lifting member 52 that is located below the case body 20C in the protruding position.

[0047] One end of the link 58 is coupled to the cylindrical body 5002 of the stopper member 50 via a first connecting pin 5802, and the other end of the link 58 is coupled to the inner ring of the one-way clutch 62 via a second connecting pin 5804. The inner ring of the one-way clutch 62 is rotatably supported by a shaft (not shown) provided in the case main body 20C, and the pinion 60 is provided on the outer ring of the one-way clutch 62 and can mesh with the rack 56. When the lifting member 52 descends from the elevated position to the lowered position, the outer ring and the inner ring rotate together, causing the inner ring to rotate once, and the second connecting pin 5804 also rotates once together with the inner ring. When the lifting member 52 ascends from the lowered position to the elevated position, only the outer ring rotates, and the inner ring and the second connecting pin 5804 remain stationary.

[0048] 18, when the stopper pin 5006 is in the protruding position, the tip of the stopper pin 5006 is located below the lower end of the mounting plate 2212 of the lid 22C and engages with the lower end of the mounting plate 2212 from below, thereby holding the lid 22C in the open position. In this state, when the battery module 12A is inserted into the accommodation chamber 28 as shown in Fig. 19, the battery module 12A presses down the lifting member 52 via the inclined guide surface 5202, and the lifting member 52 descends from the raised position to the lowered position. As the elevating member 52 moves from the raised position to the lowered position, the inner and outer rings of the one-way clutch 62 rotate together, causing the outer and inner rings to rotate together with the pinion 60, and the second connecting pin 5804 begins to rotate. As this occurs, the stopper pin 5006 retracts from the protruding position via the link 58 and the stopper member 50, as shown in Figure 20. As a result, the cylindrical surface at the lower end of the mounting plate 2212 moves over the spherical surface at the tip of the stopper pin 5006, causing the lid 22C to swing from the open position to the closed position. Eventually, the tip of the stopper pin 5006 moves away from the lower end of the mounting plate 2212 of the lid 22C, causing the lid 22C to swing to the closed position, as shown in Figure 21, and the storage chamber 28 is closed by the lid 22C. Note that one rotation of the second connecting pin 5804 returns the stopper pin 5006 to the protruding position.

[0049] When removing the battery module 12A, as shown in Fig. 22 , the cover 22C is manually swung from the closed position to the open position, causing the lower end of the mounting plate 2212 of the cover 22C to push in the stopper pin 5006, which compresses the compression coil spring 5004 and retracts the stopper pin 5006 from the extended position. When the lower end of the mounting plate 2212 of the cover 22C passes over the stopper pin 5006, the compression coil spring 5004 causes the stopper pin 5006 to return to the extended position and engage with the lower end of the mounting plate 2212 from below, maintaining the cover 22C in the open position. When removing the battery module 12A, as shown in Fig. 23 , as the battery module 12A moves toward the opening 26, the battery module 12A is no longer above the lifting member 52, causing the lifting member 52 to rise from the lowered position to the raised position. At this time, the pinion 60 is rotated by the rack 56, but the second connecting pin 5804 remains stationary, the stopper pin 5006 is maintained in the protruding position, and the cover 22C is maintained in the open position.

[0050] According to the third embodiment, when removing the battery module 12A from the battery case 14C, the lid 22C is manually swung from the closed position to the open position, and when the battery module 12A is placed back into the battery case 14C, the lid 22C automatically swung from the open position to the closed position. This is advantageous in terms of improving work efficiency during the manufacture of the battery pack 10C, or during maintenance, inspection, reuse, or recycling of the battery pack 10C.

[0051] Fourth Embodiment Next, a battery pack 10D according to a fourth embodiment will be described with reference to Figures 24 and 25. The fourth embodiment is a modification of the first embodiment, and includes a protrusion mechanism 64 that causes the battery modules 12A to protrude from the openings 26 when the lid 22D is pivoted from the closed position to the open position, thereby facilitating removal of the battery modules 12A. In the fourth embodiment, as in the third embodiment, the lid 22D is configured to individually open and close the multiple openings 26. The structure and support structure of the lid 22D are similar to those of the third embodiment, and the structure of the battery modules 12A, the structure of the case body 20D, the structure of the storage chambers 28 provided in the case body 20D, and the structure of the connecting members 24B provided in the case body 20D are substantially similar to those of the first embodiment.

[0052] The protrusion mechanism 64 includes a lifting member 66 and a rod 68. The lifting member 66 is provided at a location on the bottom wall 2004 of the case body 20D that corresponds to a location near the intermediate wall 2008 of each storage chamber 28, so as to protrude into and retract within the storage chamber 28. The lifting member 66 is guided by a guide (not shown) provided on the bottom wall 2004 of the case body 20D along the height direction of the storage chamber 28 between a raised position where it protrudes into the storage chamber 28 as shown in FIG. 25 and a lowered position where it is positioned on the underside of the storage chamber 28 as shown in FIG. 24. The lifting member 66 is biased by a coil spring 70 to always position the lifting member 66 in the raised position, and the raised position is determined by abutting against a stopper pin 6610 provided on the case body 20D. The upper end of the coil spring 70 is attached to a bracket (not shown) provided on the case body 20D, and the lower end of the coil spring 70 is attached to the upper part of the lifting member 66. The upper side of the lifting member 66 is provided with a battery module inclined surface 6602 that allows the battery module 12A to protrude through the opening 26, and the lower side of the lifting member 66 is provided with a rod inclined surface 6604 that engages with the tip 6802 of the rod 68. The rod 68 is composed of two separate sections: a first rod section 68A and a second rod section 68B. A cylindrical section 68C provided at the end of the second rod section 68B accommodates a flange 68D at the end of the first rod section 68A, and the flange 68D is biased by a coil spring 68E in a direction that causes the first rod section 68A to protrude from the cylindrical section 68C. The first rod section 68A is movably supported by a support wall 2042 that protrudes from the bottom wall 2004 of the case main body 20D. A coil spring 6810 wound around the first rod portion 68A is provided between the cylindrical portion 68C and the support wall 2042, and biases the cylindrical portion 68C away from the support wall 2042. As shown in Figure 24, when the cover 22D is in the closed position, the tip 6804 of the first rod portion 68A engages with the mounting plate portion 2212, and the tip 6802 of the second rod portion 68B engages with the upper and lower middle portion of the rod inclined surface 6604 of the elevating member 66, and the rod 68 is in the protruding position.As shown in Figure 25, when the cover body 22D is in the open position, the tip 6804 of the first rod portion 68A engages with the mounting plate portion 2212 from below, and the tip 6802 of the second rod portion 68B engages with the lower part of the rod inclined surface 6604 of the lifting member 66, and the rod 68 is in the retracted position.

[0053] 24 and 25 , in the fourth embodiment, when the lid 22D is manually swung from the closed position to the open position, the lifting member 66 rises via the rod 68 and the rod inclined surface 6604, and the battery module 12A protrudes from the opening 26 via the battery module inclined surface 6602. When the lid 22D is swung from the closed position to the open position, if the distance that the lid 22D moves in the battery module 12A installation / removal direction is shorter than the distance that the battery module 12A is pushed out by the battery module inclined surface 6602, the coil spring 68E is compressed to absorb the difference in these distances. 25, when the lower end of mounting plate 2212 of lid 22C passes over tip 6804 of first rod 68A, coil spring 68E is compressed, and when the lower end of mounting plate 2212 of lid 22C passes over tip 6804 of first rod 68A, rod 68 is caused to protrude by coil spring 68E and engages with the lower end of mounting plate 2212 from below, maintaining lid 22C in the open position. Therefore, in the fourth embodiment, open position holding mechanism 42 that holds lid 22D in the open position where opening 26 is open is configured to include rod 68. Furthermore, when the battery module 12A is inserted into the storage chamber 28 and the lid 22D is closed, the lifting member 66 descends via the corner of the battery module 12A and the battery module inclined surface 6602, the rod 68 is brought to the protruding position via the rod inclined surface 6604, the tip 6804 of the first rod portion 68A engages with the mounting plate portion 2212, and the lid 22D is held in the closed position by the biasing force of the spring member 48. Therefore, in the fourth embodiment, the closed position holding mechanism 44 that holds the lid 22D in the closed position that closes the opening 26 includes the rod 68 and the spring member 48. According to the fourth embodiment, when the lid 22D is swung from the closed position to the open position, the battery module 12A protrudes from the opening 26 by the protruding mechanism 64, which makes it easy to remove the battery module 12A from the storage chamber 28, which is more advantageous in improving work efficiency during maintenance and inspection of the battery pack and when reusing and recycling the battery pack.

[0054] In the embodiment, the opening 26 is opened and closed by the lids 22A, 22B, 22C, and 22D, which are pivotally mounted on the case bodies 20A, 20B, 20C, and 20D via hinges 32 and support shafts 2216. However, the lids only need to be able to open and close the opening 26, and the structure by which the lids are attached to the case bodies is not limited to the embodiment. For example, the lids and the case bodies may be formed as separate members, and the lids may be detachably attached to the case bodies. In this case, for example, the lids may be slidably attached to grooves formed in the case bodies in a direction that opens and closes the opening 26. Furthermore, in the embodiment, the lids completely cover the opening when in the closed position. However, as long as the battery modules are maintained in the storage chambers 28 when the lids are in the closed position, the lids do not necessarily have to completely cover the opening 26; they may only partially cover the opening 26. Furthermore, in this embodiment, a battery pack used in an electric vehicle or hybrid vehicle using a motor as a drive source has been described. However, the use of the battery pack of the present invention is not limited to electric vehicles, and it can be widely applied to a variety of fields, such as electric construction machinery such as bulldozers and backhoes, and electric traveling robots.

[0055] 10A, 10B, 10C, 10D Battery pack 12A, 12B Battery module 1202 Side surface 1204 Top surface 1206 Bottom surface 1208 End surface 14A, 14B, 14C Battery case 16 Battery cell 18 Electrode terminal 18A Positive electrode terminal 18B Negative electrode terminal 20A, 20B, 20C, 20D Case body 2002 Top wall 2004 Bottom wall 2006 Side wall 2008 Intermediate wall 2010 Partition wall 2012 Cutout portion 2014 Case body end surface 2016 Bulging portion 2018 Screw hole 2020 Pair of end walls 2022 Pair of side walls 2024 Bottom wall 2026 First partition wall 2028 Second partition wall 2030 Notch portion 2032 Case body end surface 2034 Bulging portion 2036 Screw hole 2040, 2042 Support wall 22A, 22B, 22C, 22D Cover 2202 Bulging portion 2204 Screw insertion hole 2206 Bulging portion 2208 Screw insertion hole 2210 Body plate portion 2212 Mounting plate portion 2214 Support shaft insertion hole 2216 Support shaft 24A, 24B Connecting member 2402 Contact portion 2404 Non-contact portion 26 Opening 28 Storage chamber 30 Case half portion 32 Hinge 34 Bolt 36 Sealing member 38 Biasing member 40 Output connecting member 42 Open position holding mechanism 44 Closed position holding mechanism 46 Movement mechanism 48 Spring member 50 Stopper member 5002 Cylindrical body 5004 Compression coil spring 5006 Stopper pin 52 Lifting member 5202 Inclined guide surface 54 Compression coil spring 56 Rack 58 Link 5802 First connecting pin 5804 Second connecting pin 60 Pinion 62 One-way clutch 64 Protrusion mechanism 66 Lifting member 6602 Inclined surface for battery module 6604 Inclined surface for rod 6610 Stopper pin 68 Rod 6802 Tip 6804 Base end 68A First rod portion 68B Second rod portion 68C Cylindrical portion 68D Flange 68E Coil spring 6810 Coil spring 70 Coil spring

Claims

1. A battery pack comprising a plurality of battery modules and a battery case housing the battery modules, wherein the battery case comprises a case body having a plurality of storage chambers each having an opening through which each battery module can be individually inserted and removed, and a lid for opening and closing the openings of the plurality of storage chambers, wherein the case body is provided with connection members which are connected to the electrode terminals of the plurality of battery modules and electrically connect the battery modules housed in the plurality of storage chambers with the battery modules housed in each of the plurality of storage chambers and the openings closed by the lid.

2. The battery pack structure according to claim 1, characterized in that: the battery module is elongated with a width, a height, and a length that is greater than the width and height; each of the multiple storage chambers is elongated with a width, height, and length corresponding to the battery module; the multiple storage chambers are formed to accommodate the multiple battery modules lined up with their lengths parallel; the openings are provided at one end of each of the multiple storage chambers in the longitudinal direction; and the lid is provided to open and close the multiple openings.

3. The battery pack structure according to claim 2, characterized in that: the case body has a width that is greater than the width of the battery modules, a height that is greater than the height of the battery modules, and a length that is greater than the width and height of the case body, the case body comprises a pair of case halves divided in half in the longitudinal direction, the multiple storage chambers are formed in each of the case halves such that the battery modules stored in the storage chambers of each case half are aligned in a straight line in the longitudinal direction of the case body and the battery modules stored in the storage chambers of each case half are stored with their longitudinal directions parallel and aligned in the width direction of the case body, the openings are provided at both ends of the longitudinal direction of the case body, and the lid is provided to open and close the multiple openings at both ends of the longitudinal direction of the case body.

4. The battery pack structure according to claim 3, characterized in that the battery pack supplies power to a drive motor of an electric vehicle, and the case body is attached to the body of the electric vehicle with the longitudinal direction of the case body aligned with the width direction of the electric vehicle.

5. The battery pack structure according to claim 1, characterized in that: the battery module is elongated with a width, a height, and a length that is greater than the width and height; each of the multiple storage chambers is elongated with a width, height, and length corresponding to the battery module; the multiple storage chambers are formed to accommodate the multiple battery modules lined up with their lengths parallel; the openings are provided at one end of each of the multiple storage chambers in the height direction; and the lid is provided to open and close the multiple openings.

6. The battery pack structure according to claim 5, characterized in that the case body has a width that is greater than the width of the battery modules, a height that is greater than the height of the battery modules, and a length that is greater than the width and height of the case body, and the multiple storage chambers are formed so that, in each longitudinal half of the case body, the battery modules stored in the storage chambers of each half are aligned in a straight line in the longitudinal direction of the case body, and the battery modules stored in each half are stored in a state where they are aligned in the width direction of the case body with their longitudinal directions parallel.

7. The battery pack structure according to claim 1, characterized in that: the battery module is elongated with a width, a height, and a length that is greater than the width and height; each of the multiple storage chambers is elongated with a width, height, and length corresponding to the battery module; the multiple storage chambers are formed to accommodate the multiple battery modules lined up with their lengths parallel to each other; the openings are provided at one end of the multiple storage chambers in the longitudinal direction; the lid body is provided to open and close the multiple openings individually; and further comprising an open position holding mechanism that holds the lid body in an open position where the openings are open; a closed position holding mechanism that holds the lid body in a closed position where the openings are closed; and a moving mechanism that releases the holding of the lid body by the open position holding mechanism and moves the lid body from the open position to the closed position when the battery module is accommodated in the storage chamber with the lid body in the open position.

8. The battery pack structure according to claim 1, characterized in that: the battery module is elongated with a width, a height, and a length that is greater than the width and height; each of the multiple storage chambers is elongated with a width, height, and length corresponding to the battery module; the multiple storage chambers are formed to accommodate the multiple battery modules lined up with their lengths parallel to each other; the openings are provided at one end of the multiple storage chambers in the longitudinal direction; the lid is provided to open and close the multiple openings individually; and further comprising: an open position holding mechanism that holds the lid in an open position with the openings open; a closed position holding mechanism that holds the lid in a closed position with the openings closed; and a protrusion mechanism that causes the battery module to protrude from the opening when the lid is opened with the battery module accommodated in the storage chamber.

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