Battery pack

Abstract

In a battery pack, an exterior case, which houses an assembled battery, is made of resin, and has a rectangular parallelepiped shape, has pin insertion holes at four corners of a main surface, a side surface, and an end surface, and a resin block that has pin insertion holes forms therein is integrally molded with the exterior case. The plurality of pin insertion holes include a first pin insertion hole, a second pin insertion hole, and a third pin insertion hole, and each pin insertion hole fixes an insert collar to an opening. In a composite corner part, a third resin block is formed at a corner part of an end surface. A first resin block and a second resin block are integrally connected to the third resin block. A step surface is provided along an outer peripheral surface of the third resin block at a boundary part between the main surface, the side surface, and the end surface. A step recess part is formed in the composite corner part.

Description

Battery pack

[0001] The present invention relates to a battery pack containing a large number of battery cells.

[0002] Battery packs containing a large number of chargeable and dischargeable battery cells have been developed. These battery packs are used as power sources for electric vehicles, electric heavy machinery, forklifts, and the like. In particular, in recent years, there has been a demand for higher capacity battery packs, and battery packs containing a larger number of battery cells have been adopted. Such battery packs containing a large number of battery cells are quite heavy, weighing between 10 kg and several tens of kg. Therefore, when transporting or installing them, they can be lifted efficiently using a lifting device such as a crane or lift.

[0003] In this way, a method for lifting a heavy battery pack can be conveniently achieved by connecting detachable lift pins to the exterior case of the battery pack and pulling up these lift pins with a lifting machine such as a crane or lift. In order to lift the battery pack with a lifting machine via the lift pins in this way, by connecting the lift pins to multiple locations on the exterior case of the battery pack, for example, to the four corners of the top surface of the exterior case in the case of a rectangular parallelepiped exterior case, even a heavy battery pack can be lifted in a balanced and stable manner.

[0004] Such lift pins are generally cylindrical and have a retractable locking portion at the tip, such as a ball lock pin. The battery pack can be lifted by inserting the pin body of each lift pin into pin insertion holes provided at the four corners of the top surface of the exterior case, locking the locking portions inside the pin insertion holes, and then simultaneously pulling up the lift pins in this state.

[0005] However, the installation orientation of a battery pack varies depending on the state and conditions of use. For example, in a battery pack whose exterior case is a rectangular box, it is not possible to determine which of the three adjacent faces that are vertically positioned faces upward when the battery pack is installed. For this reason, in a rectangular battery pack, the face that will be the upper face when the battery pack is in use must be the lifting face, and pin insertion holes for connecting lift pins must be provided at the four corners of the lifting face. If the lifting face differs depending on the product, it is necessary to design each product separately.

[0006] In addition, the battery pack's posture when installed in the main device is not necessarily optimal for transportation, and depending on the product, the battery pack may be efficiently loaded and transported in an upright position during transportation, but when installed in the main device, it may be placed in a horizontal position due to the position of the output terminals. For this reason, a structure was needed that allows convenient lifting by connecting lift pins even when the lifting surface is different during transportation and installation.

[0007] JP 2017-162703 A JP 2016-24856 A

[0008] The present invention was developed with the aim of overcoming the above-mentioned drawbacks of the conventional technology, and one of the objects of the present invention is to provide a battery pack that can be lifted using lift pins in the normal directions of three mutually perpendicular faces of the box-shaped outer case while connecting the lift pins to the four corners of the top surface of the outer case.

[0009] A battery pack according to one aspect of the present invention includes a battery assembly including a plurality of battery cells and a resin outer case that houses the battery assembly. The outer case has a rectangular box-like outer shape and includes a pair of opposing main surfaces, a pair of opposing side surfaces that connect the side edges of the pair of main surfaces, and a pair of opposing end surfaces that connect the edges of the pair of main surfaces and the pair of side surfaces. The outer case has a plurality of pin insertion holes at the four corners of the main surfaces, the side surfaces, and the end surfaces, to which lift pins for lifting the battery pack are connected. The pin insertion holes include first pin insertion holes at the four corners of the main surfaces, second pin insertion holes at the four corners of the side surfaces, and third pin insertion holes at the four corners of the end surfaces. Insert collars for engaging the lift pins are inserted into the openings of the pin insertion holes to secure the pins. The plurality of resin blocks include a first resin block having a first pin insertion hole formed therein, a second resin block having a second pin insertion hole formed therein, and a third resin block having a third pin insertion hole formed therein. A corner portion formed by the main surface, side surface, and end surface, which have pin insertion holes at four corners, is a composite corner portion having the first, second, and third pin insertion holes. In the composite corner portion, the third resin block is molded at a corner portion of the end surface, so that the third pin insertion hole is opened in the end surface. The first resin block is adjacent to and integrally connected to the third resin block, so that the first pin insertion hole is opened in the main surface. The second resin block is adjacent to and integrally connected to the third resin block, so that the second pin insertion hole is opened in the side surface. At the boundary between the main surface, side surface, and end surface, a stepped surface formed lower than the main surface and the side surface is provided along the outer circumferential surface of the third resin block, thereby forming a stepped recess in the composite corner portion.

[0010] The battery pack of the present invention has the advantage that when lifting the battery pack using lift pins, the battery pack can be lifted in the normal directions of three mutually perpendicular faces of the box-shaped outer case while the lift pins are connected to the four corners of the top surface of the outer case.

[0011] 1 is a perspective view of a battery pack according to an embodiment of the present invention. 1 is an exploded perspective view of the battery pack shown in FIG. 1. 2 is a rear perspective view of the battery pack shown in FIG. 2, seen from below. 3 is an exploded perspective view of the battery assembly of the battery pack shown in FIG. 2. 4 is an enlarged perspective view of a composite corner portion of the battery pack shown in FIG. 1. 5 is a horizontal cross-sectional view of the composite corner portion shown in FIG. 5. 6 is an exploded cross-sectional view corresponding to the cross-section of line VII-VII of the composite corner portion shown in FIG. 7. 7 is a cross-sectional view of line VIII-VIII of the composite corner portion shown in FIG. 6, showing the insertion state of the lift pin. 8 is a view showing the engagement state of the lift pin in the composite corner portion shown in FIG. 8. 9 is an enlarged perspective view of the lid case shown in FIG. 3, seen from the inside. 10 is a perspective view showing the state in which the battery pack shown in FIG. 1 is lifted using a lift pin. 11 is a perspective view showing the state in which the battery pack shown in FIG. 1 is lifted in different positions. 12 is a perspective view of a battery pack according to a second embodiment of the present invention. 13 is a rear perspective view of the battery pack shown in FIG. 14, seen from below. 14 is a perspective view showing an example of a battery pack according to a comparative example. 15 is an exploded perspective view of the battery pack shown in FIG. 16.

[0012] First, we will explain one of the key features of the present invention. When a battery pack, which houses a battery pack including multiple battery cells housed in a box-shaped outer case, is to be lifted using a lifting device such as a crane or lift by connecting lift pins to the four corners of the top surface, pin insertion holes for inserting the lift pins must be provided at the four corners of the top surface, which serves as the lifting surface. In particular, to lift the battery pack while changing its orientation, pin insertion holes must be provided at the four corners of the surface that can serve as the lifting surface. However, in a plastic outer case, it is difficult to provide pin insertion holes directly, as is the case with a metal case, due to structural and strength issues. However, when providing pin insertion holes at the four corners of the surface that serves as the lifting surface of a box-shaped outer case, multiple pin insertion holes must be provided in intersecting directions at one corner in order to use multiple surfaces as lifting surfaces, which may reduce the strength of the corners. In a resin outer case, reduced corner strength reduces safety when lifting using lift pins. Furthermore, drilling multiple through-holes in the outer case is not desirable in order to make the outer case waterproof.

[0013] To solve the above problems, a comparative battery pack 90 was prototyped as shown in Figures 16 and 17. The battery pack 90 has a waterproof resin exterior case and can lift the battery pack in different directions. This battery pack 90 has cube-shaped corner blocks 95 fixed to each corner of a rectangular parallelepiped resin exterior case 93. These corner blocks 95 are fixed to connecting recesses 94 in the exterior case 93 via fixing screws 96. Each corner block 95 has pin insertion holes 98 for inserting lift pins in pin connecting surfaces 97 that are perpendicular to each other. By fixing the corner blocks 95 to each corner of the exterior case 93, the battery pack 90 can have pin insertion holes 98 that open in three directions at each corner. By connecting lift pins to the pin insertion holes 98 in the corner blocks 95 located at the four corners of the top surface of the exterior case 93, the box-shaped exterior case 93 can be lifted using any of its faces as the upper surface.

[0014] However, a battery pack with this structure requires manufacturing multiple corner blocks separately from the outer case, and each corner block must be fixed to a corner of the outer case, which increases the cost of parts and the number of manufacturing processes, resulting in higher manufacturing costs.

[0015] In order to solve the above problems, the inventors conducted further prototyping and discovered a structure in which the outer case is made of resin and has a structure in which multiple pin connection holes are provided in one corner in intersecting directions, while preventing a decrease in the strength of the corners of the outer case and allowing for safe lifting via lift pins. The present invention provides a technology that reduces manufacturing costs by using a resin outer case, prevents a decrease in the strength of the corners, and when lifting a battery pack using lift pins, allows the lift pins to be connected to the four corners of the top surface of the outer case and lift the battery pack in the normal directions of three mutually perpendicular surfaces.

[0016] A battery pack according to one embodiment of the present invention includes a battery assembly including a plurality of battery cells and a resin outer case that houses the battery assembly. The outer case has a rectangular box-like outer shape and includes a pair of opposing main surfaces, a pair of opposing side surfaces that connect the side edges of the pair of main surfaces, and a pair of opposing end surfaces that connect the edges of the pair of main surfaces and the pair of side surfaces. The outer case has a plurality of pin insertion holes at the four corners of the main surfaces, the side surfaces, and the end surfaces, to which lift pins for lifting the battery pack are connected. The pin insertion holes include first pin insertion holes at the four corners of the main surfaces, second pin insertion holes at the four corners of the side surfaces, and third pin insertion holes at the four corners of the end surfaces. Insert collars for engaging the lift pins are inserted into the openings of the pin insertion holes to secure the pins. The plurality of resin blocks include a first resin block having a first pin insertion hole formed therein, a second resin block having a second pin insertion hole formed therein, and a third resin block having a third pin insertion hole formed therein. A corner portion formed by the main surface, side surface, and end surface, which have pin insertion holes at four corners, is a composite corner portion having the first, second, and third pin insertion holes. In the composite corner portion, the third resin block is molded at a corner portion of the end surface, so that the third pin insertion hole is opened in the end surface. The first resin block is adjacent to and integrally connected to the third resin block, so that the first pin insertion hole is opened in the main surface. The second resin block is adjacent to and integrally connected to the third resin block, so that the second pin insertion hole is opened in the side surface. At the boundary between the main surface, side surface, and end surface, a stepped surface formed lower than the main surface and the side surface is provided along the outer circumferential surface of the third resin block, thereby forming a stepped recess in the composite corner portion.

[0017] The above configuration has the advantage that the battery pack can be lifted in the normal directions of three mutually orthogonal surfaces of the box-shaped outer case while connecting lift pins to the four corners of the top surface of the outer case. This is because the above battery pack has pin insertion holes for connecting lift pins at the four corners of the main surface, side surfaces, and end surfaces of the outer case. Because the pin insertion holes are provided at the four corners of the main surface, side surfaces, and end surfaces of the outer case, the battery pack can be lifted by connecting lift pins to the pin insertion holes located at the four corners of the top surface, regardless of which side has the pin insertion holes located at the four corners. This realizes the advantage of being able to lift the box-shaped outer case in the normal directions of three mutually orthogonal surfaces. For example, by providing pin insertion holes at the four corners of three mutually orthogonal surfaces of the six faces of a rectangular parallelepiped outer case, the above battery pack can be lifted by connecting lift pins to the pin insertion holes located at the four corners of the top surface, regardless of which side has the pin insertion holes located at the four corners of the top surface.

[0018] The above-described exterior case is formed by integrally molding multiple resin blocks with pin insertion holes formed on the inside in a non-through state, and the corner portion formed by the main surface, side surface, and end surface where the pin insertion holes are provided at the four corners is a composite corner portion with first to third pin insertion holes. The first to third resin blocks with the first to third pin insertion holes formed therein are integrally molded in this composite corner portion. Therefore, the composite corner portion with the first to third pin insertion holes is waterproof, and by integrally molding the first to third resin blocks, the composite corner portion with the first to third pin insertion holes is increased in rigidity, allowing it to be stably lifted with a lift pin. Furthermore, a stepped surface formed one step lower than the main surface and side surface is provided along the outer peripheral surface of the third resin block in the composite corner portion to form a stepped recess, thereby reducing the thickness of the resin at the corner portion and preventing sink marks that occur during resin molding, resulting in a beautiful appearance.

[0019] In a battery pack according to another embodiment of the present invention, the exterior case has pin insertion holes at the four corners of the six faces that form the rectangular parallelepiped, so that all corners can be composite corners.

[0020] According to the above configuration, pin insertion holes are provided at the four corners of the six faces of the outer case, and the eight corners are made into composite corners. Therefore, even when the battery pack is placed with any face of the outer case facing upward, the battery pack can be lifted by connecting lift pins to the pin insertion holes located at the four corners of the top face.

[0021] In another embodiment of the battery pack of the present invention, a pin insertion hole can be formed by fixing a cylindrical insert collar having an inner diameter that allows a lift pin in an unlocked position to pass through but not a lift pin in a locked position, into the opening of a cylindrical pilot hole formed in a resin block and having an inner diameter and depth that allow a lift pin in a locked position to pass in and out.

[0022] The above-described configuration has the advantage that the insertion and removal and locking of the lift pins can be reliably controlled while the pin insertion holes have a simple structure.

[0023] In a battery pack according to another embodiment of the present invention, the insert collar includes a cylindrical tube portion having irregularities on the outer circumferential surface, and this tube portion can be press-fitted into the prepared hole to be fixed.

[0024] According to the above configuration, by press-fitting the cylindrical portion having the irregularities on its outer peripheral surface into the opening of the pilot hole, the insert collar can be pressed against the inner surface of the pilot hole and reliably fixed.

[0025] In a battery pack according to another embodiment of the present invention, a first resin block can be integrally molded into a third resin block together with a main surface plate that forms the main surface and an end surface plate that forms the end surface, and a second resin block can be integrally molded into a third resin block together with a side surface plate that forms the side surface and an end surface plate that forms the end surface.

[0026] According to the above configuration, the first resin block is integrally molded with the main surface plate, the end surface plate, and the third resin block, and the second resin block is integrally molded with the side surface plate, the end surface plate, and the third resin block, thereby preventing the thickness of the first resin block and the second resin block from increasing, thereby increasing strength while preventing the occurrence of sink marks during resin molding.

[0027] In a battery pack according to another embodiment of the present invention, the first resin block and the second resin block can have their opening-side leading ends projecting from the step surface as arc-shaped exposed portions.

[0028] According to the above configuration, the tip portion on the opening side of the first resin block integrally molded with the main plate protrudes from the step surface as an arc-shaped exposed portion, and the tip portion on the opening side of the second resin block integrally molded with the side plate protrudes from the step surface as an arc-shaped exposed portion. This effectively prevents the first and second resin blocks from becoming thicker at the interference area with the step surface, thereby preventing sink marks during resin molding and improving the appearance.

[0029] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or members.

[0030] Furthermore, the embodiments shown below are specific examples of the technical concept of the present invention and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended as examples and are not intended to limit the scope of the present invention thereto. Furthermore, the content described in one embodiment or example can also be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity of explanation.

[0031] (Embodiment 1) A battery pack according to one embodiment of the present invention is shown in Figures 1 to 10. In these figures, Figure 1 is a perspective view of the battery pack, Figure 2 is an exploded perspective view of the battery pack shown in Figure 1, Figure 3 is an exploded rear perspective view of the battery pack shown in Figure 2, seen from below, Figure 4 is an exploded perspective view of the battery pack, Figure 5 is an enlarged perspective view of a composite corner portion of the exterior case, Figure 6 is a horizontal cross-sectional view of the composite corner portion of Figure 5, Figures 7 and 8 are cross-sectional views taken along lines VII-VII and VIII-VIII in Figure 6, Figure 9 is a cross-sectional view showing the locked state of the lift pin in Figure 8, and Figure 10 is an enlarged bottom perspective view of the lid case. The battery pack shown in these figures includes a battery pack 2 including a plurality of battery cells 1 and a resin exterior case 3 that houses the battery pack 2. The battery pack 100 can be lifted by connecting lift pins to the four corners of the top surface of the exterior case 3 in which the assembled battery 2 is housed, thereby improving work efficiency during transportation and installation.

[0032] (External Case 3) The external case 3 has a rectangular box shape. This external case 3 is made of a material with excellent insulating properties, such as a resin such as polycarbonate or PC-ABS alloy. The rectangular external case 3 has six outer surfaces: a pair of main surfaces 31 arranged opposite each other; a pair of side surfaces 32 arranged opposite each other and connecting the side edges of the pair of main surfaces 31; and a pair of end surfaces 33 arranged opposite each other and connecting the edges of the pair of main surfaces 31 and the pair of side surfaces 32. Specifically, the six surfaces of the external case 3 are composed of the pair of main surfaces 31 consisting of a first main surface 31A and a second main surface 31B arranged parallel to each other; the pair of side surfaces 32 consisting of a first side surface 32A and a second side surface 32B arranged parallel to each other; and the pair of end surfaces 33 consisting of a first end surface 33A and a second end surface 33B arranged parallel to each other.

[0033] The exterior case 3 shown in Figures 2 and 3 is divided into two parts, a main case 3A and a lid case 3B, at the midpoint between the main surface 31 and the side surface 32. The main case 3A and the lid case 3B are shaped like a container, with a main plate 41 and a side plate 42 attached as a peripheral wall 40 around an end plate 43 that forms the end surface 33. This creates a storage compartment 34 for storing the battery pack 2. The main case 3A and the lid case 3B have different heights for the peripheral walls 40A, 40B connected to the end plate 43, making the main case 3A deeper than the lid case 3B. The main case 3A and the lid case 3B are formed into a cylindrical shape by connecting the main plate 41 that forms the main surface 31 and the side plate 42 that forms the side surface 32 at their opposite edges. The end plate 43 is connected to one end surface, and the other end surface is an opening, forming a deep container shape. Furthermore, the exterior case 3 shown in the figures has positive and negative external output terminals 8 attached to the lid case 3B.

[0034] The exterior case 3 shown in Figures 2 and 3 has multiple rows of grooves 44 formed on the surfaces of the main plate 41 and side plate 42, which make up the peripheral wall 40. The multiple grooves 44 are parallel to one another and extend in the height direction of the peripheral wall 40. The exterior case 3 shown in the figures has grooves 44 formed throughout the entire peripheral wall 40, reducing the overall weight of the exterior case 3 and increasing the surface area, thereby improving the heat dissipation characteristics of the exterior case 3. The main case 3A and the lid case 3B have multiple rows of grooves 44 formed from the end plate 43 toward the opening, but do not have grooves 44 on the edge of the opening; instead, flanges 45, 46 are formed along the edge of the opening. The main case 3A and the lid case 3B are connected to each other by connecting the opposing flanges 45, 46 via set screws 18. As shown in FIG. 3, the cover case 3B has a flange portion 46 provided with an insertion hole 46a for inserting the set screw 18, and the main body case 3A has a flange portion 45 serving as a boss into which the set screw 18 is screwed.

[0035] Furthermore, the main case 3A and the lid case 3B are connected to each other at the opposing opening edges via packing 19 in a waterproof structure. The packing 19 shown in Fig. 2 is a rubber packing having a predetermined thickness and a generally rectangular shape in plan view that fits along the opening end surfaces of the main case 3A and the lid case 3B, and is disposed along a vertical groove 47 provided in the opening end surface of the main case 3A. The main case 3A and the lid case 3B are connected by a set screw 18 at a position facing a groove 44 provided in the peripheral wall 40. Therefore, the packing 19 in Fig. 2 has a U-shaped detour portion 19A on the inside at a position facing the groove 44, i.e., at the position where the set screw 18 is inserted. This allows the set screw 18 to be threaded on the outside of the packing 19, preventing water from entering the screwed portion. The main case 3A and the lid case 3B are connected in a watertight structure by placing a packing 19 in a vertical groove 47 on the open end face of the main case 3A and sandwiching the packing 19 on the open end face of the lid case 3B, and by threading a setscrew 18 inserted into an insertion hole 46a in a flange portion 46 of the lid case 3B into the flange portion 45 of the main case 3A. A groove 44 with a short overall length formed in the lid case 3B also serves as a tool gap to guide a screwdriver when screwing in the setscrew 18.

[0036] 1 to 3, the rectangular parallelepiped exterior case 3 is provided with pin insertion holes 5 for connecting lift pins at the four corners of the main surface 31, the side surfaces 32, and the end surfaces 33 so that it can be lifted with any of the main surface 31, the side surfaces 32, and the end surfaces 33 facing up. As shown in FIGS. 5 to 10, the exterior case 3 has a plurality of resin blocks 6 integrally molded at the four corners of the main surface 31, the side surfaces 32, and the end surfaces 33, and the pin insertion holes 5 are formed inside these resin blocks 6.

[0037] The above-described exterior case 3 can be lifted by connecting lift pins to pin insertion holes 5 located at the four corners of the lifting surface 30, with the surface located on the top surface serving as the lifting surface 30, and simultaneously lifting the four lift pins with a lifting machine (not shown), such as a crane or lift. In this way, the battery pack of the present invention can be lifted in an orientation in which any of the main surface 31, side surface 32, and end surface 33 of the exterior case 3 is the upper surface, making it possible to lift the exterior case 3 in three mutually perpendicular directions. In this manner, in a structure in which lift pins are connected to pin insertion holes 5 located at the four corners of the lifting surface 30, which serves as the upper surface, by providing pin insertion holes 5 at the four corners of all six surfaces of the rectangular parallelepiped exterior case 3, the pin insertion holes 5 can be located at the four corners of the upper surface serving as the lifting surface 30, regardless of the orientation in which any of the six surfaces is the upper surface. The battery pack 100 shown in the first embodiment has pin insertion holes 5 at all four corners of the six faces of the rectangular parallelepiped exterior case 3, i.e., the first main face 31A, the second main face 31B, the first side face 32A, the second side face 32B, the first end face 33A, and the second end face 33B, so that the battery pack 100 can be lifted with any of the six faces of the exterior case 3 facing up. However, by providing pin insertion holes 5 at the four corners of at least three mutually orthogonal faces, the exterior case 3 can be lifted in three mutually orthogonal directions. This structure will be described in detail later.

[0038] (Pin Insertion Hole 5) As shown in Figures 5 to 9, the pin insertion holes 5 are provided in a vertical position at the four corners of the main surface 31, side surface 32, and end surface 33 of the outer case 3, and are structured to lock the lift pins inserted therein. The pin insertion holes 5 shown in Figures 6 to 9 have insert collars 51 that lock the lift pins 7 inserted into their openings to secure them. The pin insertion holes 5 shown in the figures are fixed by inserting cylindrical insert collars 51 into the openings of cylindrical pilot holes 50 formed in a resin block 6 that is integrally molded with the outer case 3. As shown in the figures, the pilot holes 50 into which the insert collars 51 are inserted have an inner diameter (d1) and depth (h1) that allow the lift pins 7 in the locked position to be inserted and removed.

[0039] (Insert Collar 51) The insert collar 51 has a cylindrical tubular portion 51A that is inserted into the pilot hole 50. The tubular portion 51A of the insert collar 51 has an inner diameter (d2) that allows the lift pin 7 in the unlocked position to pass through but not the lift pin 7 in the locked position to pass through. Furthermore, the insert collar 51 has a flange portion 51B formed by bending at the rear end of the tubular portion 51A. The pin insertion hole 5 shown in the figure has an insertion recess 52 at the opening edge of the pilot hole 50 that guides the flange portion 51B of the insert collar 51. The insertion recess 52 is a circular recess that follows the outer shape of the flange portion 51B and has a depth equal to the thickness of the flange portion 51B. This structure has the advantage that the rear end of the insert collar 51, with the tubular portion 51A inserted into the pilot hole 50, can be positioned and fixed in place.

[0040] The insert collar 51 described above is press-fitted into the pilot hole 50 and fixed in place. As shown in FIG. 7 , the insert collar 51 press-fitted into the pilot hole 50 has numerous projections and recesses 51a formed on the outer peripheral surface of the cylindrical portion 51A by knurling. When press-fitted into the opening of the pilot hole 50, the insert collar 51 is pressed against the inner surface of the pilot hole 50 and is fixed so that it will not come off even if pulled by the lift pin 7. The insert collar 51 is made of metal, and can be made of brass, for example. However, other metals can also be used for the insert collar.

[0041] As shown in FIG. 8 , when the lift pin 7 is inserted into the pin insertion hole 5 in the unlocked position, the locking portion 7B passes through the insert collar 51 and then assumes the locked position. As shown in FIG. 9 , the locking portion 7B locks with the tip of the insert collar 51, allowing the lift pin 7 to be lifted by the lift pin 7. Note that the locked state of the lift pin 7 refers to a state in which the locking portion 7B protrudes from the tip of the cylindrical pin body 7A. In the case of a ball lock pin, this refers to a state in which multiple balls 7b protrude from the outer circumferential surface of the pin body 7A (see FIG. 9 ). The unlocked state of the lift pin 7 refers to a state in which the locking portion 7B is housed inside the cylindrical pin body 7A. In the case of a ball lock pin, this refers to a state in which multiple balls 7b are housed inside the outer circumferential surface of the pin body 7A (see FIG. 8 ). Therefore, the pin insertion hole 5 is deep enough to provide space for the tip of the lift pin 7 that has passed through the insert collar 51 to protrude the locking portion 7B. For example, in a ball lock pin having an M8-sized pin body 7A as the lift pin 7 and having multiple balls 7b protruding as the locking portion 7B, the inner diameter (d1) of the pilot hole 50 can be approximately 10 mm, the depth (h1) can be 14 to 16 mm, the inner diameter (d2) of the insert collar 51 can be approximately 8 mm, the overall length (h2) can be approximately 5 mm, and the thickness of the tubular portion 51A can be approximately 1 mm.

[0042] 5 to 9, the pin insertion holes 5 formed at the four corners of each surface include first pin insertion holes 5X provided at the four corners of the main surface 31, second pin insertion holes 5Y provided at the four corners of the side surfaces 32, and third pin insertion holes 5Z provided at the four corners of the end surfaces 33. In the corner portions formed by the main surfaces 31, side surfaces 32, and end surfaces 33 where the pin insertion holes 5 are provided at the four corners, the first pin insertion holes 5X, the second pin insertion holes 5Y, and the third pin insertion holes 5Z are arranged in orientations that are perpendicular to one another, forming a compound corner portion 35 that includes the first pin insertion holes 5X, the second pin insertion holes 5Y, and the third pin insertion holes 5Z.

[0043] (Resin Block 6) As shown in FIGS. 6 to 10 , the resin blocks 6 are integrally molded with the exterior case 3 at the four corners of the main surface 31, side surfaces 32, and end surfaces 33, reinforcing the corners of the exterior case 3 where the pin insertion holes 5 are formed. The multiple resin blocks 6 include a first resin block 6X having a first pin insertion hole 5X formed therein, a second resin block 6Y having a second pin insertion hole 5Y formed therein, and a third resin block 6Z having a third pin insertion hole 5Z formed therein. In particular, at the compound corner portion 35 where the first pin insertion hole 5X, the second pin insertion hole 5Y, and the third pin insertion hole 5Z are located, the first resin block 6X, the second resin block 6Y, and the third resin block 6Z are integrally connected and molded integrally with the exterior case 3, thereby reinforcing the corner portion. Here, the strength of each resin block 6 can be increased by increasing its thickness, but this increases the likelihood of sink marks occurring during resin molding, resulting in a poor appearance. Conversely, if the thickness is made too thin, sufficient strength cannot be obtained. Therefore, taking these factors into consideration, each resin block 6 is molded to have an optimal thickness. In particular, by molding the resin block 6 so that it is partially connected integrally to the adjacent outer case 3 or resin block 6, it is possible to increase strength while reducing the thickness.

[0044] 5 and 6 , in the compound corner portion 35, a third resin block 6Z is molded into a corner portion of the end face 33, and a third pin insertion hole 5Z is opened in the end face 33, a first resin block 6X is adjacent to the third resin block 6Z and integrally connected thereto, and a first pin insertion hole 5X is opened in the main surface, and a second resin block 6Y is adjacent to the third resin block 6Z and integrally connected thereto, and a second pin insertion hole 5Y is opened in the side surface 32. Furthermore, in the compound corner portion 35, a step surface 36 formed one step lower than the main surface 31 and the side surface 32 is provided along the outer circumferential surface of the third resin block 6Z at the boundary between the main surface 31, the side surface 32, and the end face 33, thereby forming a step recess 37.

[0045] As shown in FIGS. 5 to 10 , the third resin block 6Z molded at the corner of the end face 33 is molded along the extension direction of the boundary edge between the main face 31 and the side face 32. The opening of the pilot hole 50 of this third resin block 6Z is integrally molded with the end face plate 43 that forms the end face 33. A portion of the cylindrically molded outer periphery 61 is integrally connected to the adjacent first resin block 6X, another portion of the cylindrically molded outer periphery 61 is integrally connected to the adjacent second resin block 6Y, and a portion of the bottom 62 is integrally connected to the main face 31 and the side face 32. Furthermore, one step surface 36 provided along the outer periphery of the third resin block 6Z is positioned one step lower than the main face 31, and the other step surface 36 is positioned one step lower than the side face 32. This structure prevents the thickness of the third resin block 6Z from increasing, preventing sink marks and increasing strength.

[0046] Furthermore, the first resin block 6X molded adjacent to the third resin block 6Z has the opening of the pilot hole 50 integrally molded with the main surface plate 41 forming the main surface 31, a portion of the cylindrically molded outer periphery 61 integrally connected to the end surface plate 43 forming the end surface 33, another portion of the cylindrically molded outer periphery 61 integrally connected to the adjacent third resin block 6Z, and a portion of the bottom 62 integrally connected to the bottom 62 of the second resin block 6Y. This structure prevents the thickness of the first resin block 6X from increasing, preventing sink marks and increasing strength. Furthermore, a portion of the tip of the first resin block 6X on the opening side protrudes from the step surface 36 as an arc-shaped exposed portion 38. This effectively prevents the thickness from increasing at the interference area between the first resin block 6X and the step surface 36 of the third resin block 6Z, thereby preventing sink marks during resin molding.

[0047] Furthermore, the second resin block 6Y molded adjacent to the third resin block 6Z has the opening of the pilot hole 50 integrally molded with the side plate 42 that forms the side surface 32, a portion of the cylindrically molded outer periphery 61 integrally connected to the end plate 43 that forms the end surface 33, another portion of the cylindrically molded outer periphery 61 integrally connected to the adjacent third resin block 6Z, and a portion of the bottom 62 integrally connected to the bottom 62 of the first resin block 6X. This structure prevents the second resin block 6Y from becoming thicker, preventing sink marks and increasing its strength. Furthermore, the second resin block 6Y has a portion of its tip on the opening side that protrudes from the step surface 36 as an arc-shaped exposed portion 38. This effectively prevents the thickness from becoming thicker at the interface between the second resin block 6Y and the step surface 36 of the third resin block 6Z, thereby preventing sink marks during resin molding.

[0048] As shown in Figures 11 to 13, the battery pack 100 described above can be lifted by inserting lift pins 7 into the pin insertion holes 5 at the four corners and locking them in place (see Figures 8 and 9). In this state, the lift pins 7 at the four corners can be simultaneously pulled up with a lifting machine (not shown). Figure 11 shows the state in which the end surface 33 of the outer case 3 is the upper surface, and the lift pins 7 are inserted into the pin insertion holes 5 at the four corners, with this end surface 33 serving as the lifting surface 30, to lift the battery pack. Figure 12 shows the state in which the main surface 31 of the outer case 3 is the upper surface, and the lift pins 7 are inserted into the pin insertion holes 5 at the four corners, with this main surface 31 serving as the lifting surface 30, to lift the battery pack. Furthermore, Figure 13 shows the state in which the side surface 32 of the outer case 3 is the upper surface, and the lift pins 7 are inserted into the pin insertion holes 5 at the four corners, with this side surface 32 serving as the lifting surface 30, to lift the battery pack. The battery pack 100 shown in these figures can have pin insertion holes 5 located at the four corners of the top surface, regardless of which side is facing up, and can be lifted by inserting lift pins 7 into the pin insertion holes 5 located at the four corners.

[0049] (Battery assembly 2) As shown in Figures 2 to 4, the battery pack 100 contains a plurality of battery cells 1 housed in an exterior case 3 as a battery assembly 2. The battery cells 1 are grouped in a predetermined arrangement to form battery blocks 10, and the battery blocks 10 are connected to form the battery assembly 2. The battery pack 100 shown in the figures is formed by stacking and connecting two battery blocks 10 in an upright position in the front-to-rear direction in the figures to form the battery assembly 2. The battery assembly 2 can connect the two battery blocks 10 stacked front-to-rear via a connecting member (not shown).

[0050] (Battery Cell 1) Battery cell 1 is a non-aqueous electrolyte secondary battery cell such as a lithium-ion battery. However, the present invention does not limit battery cell 1 to a lithium-ion battery; all currently used and future-developed secondary batteries, including other non-aqueous electrolyte secondary batteries and nickel-metal hydride batteries, can be used. Battery cell 1 in FIG. 4 is a cylindrical battery with electrode end faces at both ends. However, the battery pack of the present invention does not limit the battery to a cylindrical battery. This is because rechargeable prismatic batteries and other types of batteries can also be used for battery cell 1. A cylindrical battery contains electrodes and electrolyte in a cylindrical metal case. The metal case has a sealed structure in which a sealing plate is airtightly fixed to the opening of an outer can that closes the bottom. The outer can is manufactured by pressing a metal plate. The sealing plate is airtightly fixed to the periphery of the opening of the outer can by crimping via an insulating packing. A prismatic battery has insulated positive and negative electrode terminals attached to the sealing plate that closes the opening of the metal case.

[0051] (Battery Block 10) In the battery block 10, multiple battery cells 1 are arranged parallel to one another, with the electrode end faces of each battery cell 1 positioned on the same plane. In the battery block 10, multiple battery cells 1 are positioned in fixed positions using a plastic battery holder 12. The battery block 10 shown in Figure 4 houses 154 cylindrical batteries in the battery holder 12, with 11 battery cells 1 arranged in one row. In the battery block 10, each battery cell 1 is arranged parallel to the other, with the electrode end faces of the battery cells 1 positioned on the same plane, and lead plates 11 connected to the electrode end faces on the same plane.

[0052] (Lead Plates 11) The battery block 10 connects multiple battery cells 1 in parallel with each other using multiple lead plates 11. The lead plate 11 shown in FIG. 4 has a laminated structure consisting of connection lead plates 11A with connection portions that connect to the electrode end surfaces of multiple battery cells 1, and current-carrying lead plates 11B that reduce electrical resistance between battery cells 1 connected in parallel or in series. The connection lead plates 11A are connected to the electrode end surfaces using methods such as laser welding, spot welding, or ultrasonic welding. Furthermore, the battery block 10 connects the multiple battery cells 1 connected in parallel with each other in series via bus bars 14 located on the side of the battery holder 12. The battery block 10 shown in FIG. 4 has 154 battery cells 1 connected in 22 parallel and 7 series configurations. However, the number and connection state of the multiple battery cells in the battery block are not limited to these. The number and connection state of the connected battery cells can be varied in various ways.

[0053] (Battery Holder 12) The battery holder 12 in Figure 4 is designed to hold multiple battery cells 1 in fixed positions. The battery holder 12 in Figure 4 is molded from insulating plastic and has multiple battery cell 1 insertion tube portions 13 molded integrally therewith. The insertion tube portions 13 hold the battery cells 1 set therein in fixed positions. The battery holder 12 in the figure uses cylindrical battery cells 1, and the insertion tube portions 13 are shaped to insert cylindrical batteries and hold them in fixed positions. The battery holder 12 in the figure arranges 154 battery cells 1 in 11 rows in the left-right direction and 14 columns in the up-down direction, with the battery cells 1 arranged in the valleys between adjacent battery cells 1 on the left and right, similar to a rice bale stack.

[0054] As shown in Figure 4, the battery holder 12 is formed as a pair of separate cell holders 12A, 12B. Each of the cell holders 12A, 12B that make up the battery holder 12 has an insertion tube portion 13 into which a battery cell 1 is inserted in a parallel position. The insertion tube portion 13 is open at both ends, exposing the electrode end surfaces of the inserted cylindrical battery so that lead plates 11 can be connected to the electrode end surfaces. The insertion tube portions 13 of the cell holders 12A, 12B are long enough to insert approximately half of a battery cell 1. Each battery cell 1 is positioned in a fixed position in the battery holder 12 by inserting half into one cell holder 12A and the other half into the other cell holder 12B. The battery holder 12 constructed as described above has the advantage of being able to securely hold multiple battery cells 1 in fixed positions by inserting the battery cells 1 into the insertion tube portions 13 of the two separate cell holders 12A, 12B.

[0055] Furthermore, although not shown, the battery pack may also include a circuit board. The circuit board can be positioned in a fixed position in the exterior case via a board holder. For example, the board holder may be positioned between the battery block and the exterior case, with the circuit board positioned inside. The circuit board may mount electronic components (not shown) that are connected to the battery cells and implement a protection circuit for the battery cells. The protection circuit may be a circuit that prevents overcharging or overdischarging of the battery cells, a circuit that prevents overcurrent, or a circuit that cuts off current when the temperature rises abnormally.

[0056] (Embodiment 2) While the battery pack 100 according to the first embodiment has pin insertion holes 5 provided at the four corners of all six faces of the rectangular parallelepiped exterior case 3, the exterior case 3 may also have pin insertion holes 5 provided only at the four corners of at least three mutually orthogonal faces, allowing the battery pack 200 to be lifted in three mutually orthogonal directions. For example, as shown in Figures 14 and 15, this battery pack 200 may have pin insertion holes 5 provided only at the four corners of the first main face 31A, the first side face 32A, and the first end face 33A, which are three mutually adjacent faces that are orthogonal to each other. In this case, no pin insertion holes 5 are provided at the four corners of the remaining surfaces of the outer case 3, namely the second main surface 31B, the second side surface 32B, and the second end surface 33B. However, regardless of whether the first main surface 31A, the first side surface 32A, or the first end surface 33A is the upper surface, the upper surface of the outer case 3 can be used as the lifting surface 30 and the outer case 3 can be lifted by connecting lift pins to the pin insertion holes 5 provided at the four corners.

[0057] In the battery pack 200 having this structure, the first pin insertion hole 5X, the second pin insertion hole 5Y, and the third pin insertion hole 5Z are arranged perpendicular to one another at the corners formed by the first main surface 31A, the first side surface 32A, and the first end surface 33A, which have the pin insertion holes 5 at the four corners. Therefore, in this battery pack 200, this corner can be used as a composite corner portion 35, resulting in a structure similar to that of the first embodiment. In this way, an exterior case 3 having pin insertion holes 5 only at the four corners of three mutually perpendicular surfaces can be lifted in three directions by using the composite corner portion 35 as described above for at least one corner portion.

[0058] In this way, in an exterior case structured such that pin insertion holes are not provided in all four corners of the six faces, it is not necessary for all corners to be the composite corners described above, and corners may be provided with one or two of the first pin insertion hole, the second pin insertion hole, and the third pin insertion hole. In corners with this structure, there are fewer constraints between adjacent resin blocks, and therefore one or two resin blocks can be molded with a simpler structure than in a structure that provides all of the first resin block, the second resin block, and the third resin block, as described above.

[0059] However, even in corners with only one or two pin insertion holes, first, second, and third resin blocks with the same structure as the composite corner section described above can be provided. In this case, not all pilot holes are used as pin insertion holes for connecting lift pins, so the pilot holes not used as pin insertion holes are left empty without insert collars attached, thereby reducing part costs. However, to prevent the risk of accidentally inserting lift pins into pilot holes not used as pin insertion holes, a blocking member such as a blocking cap can be attached to the empty holes not used as pin insertion holes to prevent misuse. This structure uses the same mold structure to form pilot holes in each corner, orthogonal to each other, but only fixes insert collars to pilot holes used as pin insertion holes and blocks pilot holes not used as pin insertion holes. This reduces manufacturing costs and allows an outer case to have a composite corner section in a position optimal for the requirements of each product.

[0060] (Embodiment 3) Furthermore, the battery pack may have four or five surfaces with pin insertion holes at the four corners. The surfaces without pin insertion holes can be determined based on the position of the lifting surface depending on the application. For example, although not shown, the battery pack may have a structure in which no pin insertion holes are provided on the second end surface, which is the bottom surface, and pin insertion holes are provided on the four corners of the first end surface, which is the top surface, and the four surrounding surfaces, which are a pair of main surfaces and a pair of side surfaces. This battery pack may have a structure similar to that of the first embodiment, with the four corners located at the four corners of the first end surface, which is the top surface, being compound corners. This battery pack can be lifted by connecting lift pins to the pin insertion holes provided at the four corners, with the five surfaces, excluding the second end surface, which is the bottom surface, serving as lifting surfaces.

[0061] The present invention is a battery pack used as a power source for electric vehicles or electric heavy machinery, forklifts, etc., and is particularly effective for battery packs that house a large number of battery cells in an exterior case.

[0062] DESCRIPTION OF SYMBOLS 100, 200... Battery pack 1... Battery cell 2... Assembled battery 3... Outer case 3A... Main case 3B... Lid case 5... Pin insertion hole 5X... First pin insertion hole 5Y... Second pin insertion hole 5Z... Third pin insertion hole 6... Resin block 6X... First resin block 6Y... Second resin block 6Z... Third resin block 7... Lift pin 7A... Pin body 7B... Latching portion 7b... Ball 8... External output terminal 10... Battery block 11... Lead plate 11A... Connection lead plate 11B... Current-carrying lead plate 12... Battery holder 12A, 12B... Cell holder 13... Insertion tube portion 14... Bus bar 18... Set screw 19... Packing 19A... Detour portion 30... Lifting surface 31... Main surface 31A... First main surface 31B...Second main surface 32...Side surface 32A...First side surface 32B...Second side surface 33...End surface 33A...First end surface 33B...Second end surface 34...Storage section 35...Compound corner section 36...Step surface 37...Step recess 38...Exposed section 40, 40A, 40B...Peripheral wall 41...Main surface plate 42...Side surface plate 43...End surface plate 44...Groove section 45...Flange section 46...Flange section 46a...Through-hole 47...Vertical groove 50...Prepared hole 51...Insert collar 51A...Cylindrical section 51a...Unevenness 51B...Flange section 52...Fitting recess 61...Outer periphery 62...Bottom 90...Battery pack 93...External case 94...Coupling recess 95...Corner block 96...Fixing screw 97...Pin coupling surface 98...Pin insertion hole

Claims

1. A battery pack comprising: an assembled battery having a plurality of battery cells; and a resin exterior case that houses the assembled battery, wherein the exterior case has an external shape like a rectangular parallelepiped box, and comprises a pair of main surfaces arranged opposite to each other, a pair of side surfaces arranged opposite to each other and connecting side edges of the pair of main surfaces, and a pair of end surfaces arranged opposite to each other and connecting end edges of the pair of main surfaces and the pair of side surfaces, wherein the main surfaces, the side surfaces, and the end surfaces are provided with a plurality of pin insertion holes at four corners thereof to which lift pins for lifting the battery pack are connected, and the pin insertion holes are formed on the inside of a plurality of resin blocks that are integrally molded with the exterior case, and the plurality of pin insertion holes comprise: first pin insertion holes provided at the four corners of the main surfaces, second pin insertion holes provided at the four corners of the side surfaces, and third pin insertion holes provided at the four corners of the end surfaces, a first resin block having the first pin insertion hole formed therein, a second resin block having the second pin insertion hole formed therein, and a third resin block having the third pin insertion hole formed therein; and a corner portion formed by the main surface, the side surface, and the end surface having the plurality of pin insertion holes at four corner portions is a compound corner portion having the first pin insertion hole, the second pin insertion hole, and the third pin insertion hole, and in the compound corner portion, the third resin block is molded at a corner portion of the end surface and the third pin insertion hole is opened in the end surface, the first resin block is adjacent to the third resin block and integrally connected thereto and the first pin insertion hole is opened in the main surface, and the second resin block is adjacent to the third resin block and integrally connected thereto and the second pin insertion hole is opened in the side surface, A battery pack comprising: a step surface formed lower than the main surface and the side surface at the boundary between the main surface, the side surface, and the end surface, and provided along the outer peripheral surface of the third resin block, thereby forming a step recess in the compound corner portion.

2. A battery pack as described in claim 1, wherein the exterior case has the pin insertion holes at each of the four corners of six faces forming a rectangular parallelepiped, and all corners are composite corners.

3. A battery pack as claimed in claim 1 or 2, wherein the plurality of pin insertion holes are formed by fixing cylindrical insert collars having an inner diameter that allows the lift pin in an unlocked state to pass but not the lift pin in an engaged state to the openings of cylindrical pilot holes formed in the plurality of resin blocks and having an inner diameter and depth that allows the lift pin in an engaged state to pass through, the insert collars having an inner diameter that allows the lift pin in an unlocked state to pass through but not the lift pin in an engaged state.

4. A battery pack as described in claim 3, wherein the insert collar has a cylindrical tube portion having irregularities on its outer circumferential surface, and the tube portion is press-fitted into the pilot hole and fixed.

5. A battery pack as described in claim 1 or 2, wherein the first resin block is integrally molded with a main surface plate forming the main surface, an end surface plate forming the end surface, and the third resin block, and the second resin block is integrally molded with a side surface plate forming the side surface, the end surface plate forming the end surface, and the third resin block.

6. A battery pack as described in claim 5, wherein the first resin block and the second resin block have tip portions near the opening that protrude from the step surface as arc-shaped exposed portions.