Battery pack

Abstract

This battery pack comprises: a battery core pack that connects a plurality of battery blocks in a straight line; an exterior case that houses the core pack; and a securing part, wherein the exterior case comprises an outer cylinder part, a first lid part, and a second lid part, the securing part comprises a connecting shaft to be inserted into the plurality of battery blocks, a connecting nut, and a set screw, the connecting nut has on one end a first threaded hole into which the connecting shaft is screwed and has on the other end a second threaded hole into which the set screw is screwed, the core pack is clamped between the connecting nut and the connecting shaft to secure the battery blocks in a stacked state, and the set screw penetrates through the first lid part to secure the first lid part to the core pack.

Description

Battery pack

[0001] The present disclosure relates to a battery pack in which a battery core pack, which connects multiple battery blocks in the longitudinal direction, is housed in an exterior case.

[0002] Battery packs in which multiple battery cells are connected in series or parallel are used for applications requiring high output, such as electric bicycles and assisted bicycles. These battery packs can be manufactured by connecting multiple battery blocks, each consisting of multiple battery cells, to form a battery core pack, which is then housed in an exterior case. These battery packs are constructed by stacking multiple battery blocks longitudinally to form a long, slender battery core pack, which is then housed in an exterior case, making them ideal for bicycles and other applications, where convenient storage is required. In battery packs for these applications, the battery block is made up of multiple battery cells, and multiple battery blocks are further stacked longitudinally to form a battery core pack housed in an exterior case (see Patent Document 1).

[0003] WO 2022 / 163473

[0004] 13 and 14 show exploded perspective views of a battery pack 900 disclosed in Patent Document 1. In the battery pack 900 shown in the figures, multiple battery blocks 903 are stacked and connected and fixed with connecting shafts 921 to form a core pack 910, and this core pack 910 is inserted into a tubular portion 941 of an outer case 940. The outer case 940 is tubular with both ends open, and both ends of the tubular portion 941 are closed by lids 942 and 944. The lid 942 is connected to the core pack 910 with a set screw 925 that passes through it, so the lid 942 and the core pack 910 cannot be connected with sufficient strength.

[0005] The battery blocks 903 that make up the battery core pack 910 almost always have multiple battery cells positioned in fixed positions in plastic battery holders 904, ensuring insulation and enabling inexpensive mass production. Therefore, the core pack 910, which is made up of stacked battery blocks 903, has a structure in which a metal set screw 925 is screwed into the plastic battery holder 904 (resin portion) to secure the lid 942 to the core pack 910. It is difficult to screw the set screw 925 into the plastic battery holder 904 with sufficient strength, making it difficult to firmly secure the lid 942 to the core pack 910. Furthermore, the screwed portions can loosen when the battery pack is vibrated, and cracks can propagate and break in the plastic at the screwed portions when the battery pack is dropped, making it difficult to ensure high earthquake resistance and drop impact resistance. The core pack 910 can increase the fixing strength of the lid portion 942 by constructing the area where the set screw 925 is screwed in from a strong material such as metal, but this structure has the problem of increasing the manufacturing cost of the core pack 910.

[0006] The present disclosure has been developed with the aim of resolving the above-mentioned problems, and one of the purposes of the present disclosure is to provide a battery pack that firmly connects the core pack and the first lid portion of the outer case, ensuring high earthquake resistance and drop impact resistance.

[0007] A battery pack according to an embodiment of the present disclosure has all of the following configurations (a) to (g).

[0008] A battery pack having all of the following configurations (a) to (g): (a) The battery pack includes a battery core pack that linearly connects multiple battery blocks, an outer case that houses the core pack, and a fixing part that connects the outer case to the core pack. (b) The outer case includes an outer tube that houses the core pack, a first lid that closes a first end of the outer tube, and a second lid that closes a second end. (c) The fixing part includes a connecting shaft that connects the multiple battery blocks in the longitudinal direction, a connecting nut that is connected to an end of the connecting shaft, and a set screw that penetrates the first lid of the outer case and is connected to the connecting nut. (d) The connecting shaft includes a threaded part that is inserted into the multiple battery blocks. (e) The connecting nut has a first threaded hole at one end into which the threaded part of the connecting shaft is screwed, and a second threaded hole at the other end into which a set screw is screwed. (f) The core pack is sandwiched between a connecting nut and a connecting shaft that is threaded into the first screw hole of the connecting nut, securing the multiple battery blocks in a stacked state. (g) The set screw passes through the first lid and is threaded into the second screw hole of the connecting nut, securing the first lid of the outer case to the core pack.

[0009] The above battery pack provides a battery pack that can increase impact resistance by firmly connecting the core pack and the first lid portion of the exterior case.

[0010] 1 is a schematic exploded perspective view of a battery pack according to an embodiment of the present disclosure. FIG. 2 is a schematic exploded perspective view of a core pack shown in FIG. 1. FIG. 3 is a schematic exploded perspective view of a core pack shown in FIG. 2. FIG. 4 is a schematic horizontal sectional view of a battery pack. FIG. 5 is a schematic vertical sectional view of a battery pack. FIG. 6 is an enlarged sectional view of a main part showing an example of a fixing part. FIG. 7 is an enlarged sectional view of another example of a fixing part. FIG. 8 is a schematic partially enlarged sectional view showing an example of a waterproof structure for an outer tube part and a first lid part. FIG. 9 is a schematic partially enlarged sectional view showing another example of a waterproof structure for an outer tube part and a first lid part. FIG. 10 is an enlarged sectional view showing a second end side of an outer case. FIG. 11 is an enlarged sectional view of another example of a fixing part. FIG. 12 is a schematic exploded perspective view of a battery pack according to a conventional example. FIG. 13 is a schematic sectional view of a battery pack according to a conventional example.

[0011] Examples of the present disclosure will be described below with reference to the drawings. However, the examples described below exemplify battery packs that embody the technical concepts of the present disclosure, and the present disclosure does not specify the battery pack as described below. Furthermore, this specification in no way specifies the components set forth in the claims to the components of the embodiments. The dimensions, materials, shapes, relative locations, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. Note that the drawings are simplified, outlined, and schematic for explanatory purposes, and the size and positional relationships of components shown in the drawings may be exaggerated for clarity. In the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, with one component serving multiple functions, or conversely, the function of one component may be shared by multiple components.

[0012] The embodiments of the present disclosure may be specified by the following configurations and features.

[0013] A battery pack according to one embodiment of the present disclosure has all of the following configurations (a) to (g). (a) The battery pack includes a battery core pack that linearly connects multiple battery blocks, an outer case that houses the core pack, and a fixing part that connects the outer case to the core pack. (b) The outer case includes an outer tubular part that houses the core pack, a first lid that closes a first end of the outer tubular part, and a second lid that closes a second end. (c) The fixing part includes a connecting shaft that connects the multiple battery blocks in the longitudinal direction, a connecting nut that is connected to an end of the connecting shaft, and a set screw that penetrates the first lid of the outer case and is connected to the connecting nut. (d) The connecting shaft includes a threaded part that is inserted into the multiple battery blocks. (e) The connecting nut has a first threaded hole at one end into which the threaded part of the connecting shaft is screwed, and a second threaded hole at the other end into which a set screw is screwed. (f) The core pack is sandwiched between a connecting nut and a connecting shaft that is threaded into the first screw hole of the connecting nut, securing the multiple battery blocks in a stacked state. (g) The set screw passes through the first lid and is threaded into the second screw hole of the connecting nut, securing the first lid of the outer case to the core pack.

[0014] The above battery pack has the advantage of firmly connecting the core pack and the first lid of the exterior case, ensuring high earthquake resistance and drop impact resistance. This is because the above battery pack allows a connecting shaft to be inserted into a core pack in which multiple stacked battery blocks are arranged, and the connecting shaft can be threaded into a first screw hole in a connecting nut located at the end of the core pack to secure the multiple battery blocks in a stacked state between the connecting nut and the connecting shaft, and further allows a set screw that passes through the first lid to be threaded into a second screw hole in the connecting nut into which the connecting shaft that connects the core packs is threaded.

[0015] In the battery pack described above, the connecting shaft secures the battery blocks in a stacked state via the connecting nut, and the set screw passes through the first lid to secure the core pack to the outer case. A battery pack with this structure can integrally connect and secure the core pack, which is made up of multiple battery blocks, to the first lid using the connecting shaft, connecting nut, and set screw. In other words, the connecting shaft can be fastened to the connecting nut to connect and secure multiple battery blocks in a stacked state, and the set screw can be fastened to the connecting nut to secure the first lid to the core pack, thereby securing the core pack and the first lid with high connection strength. The connecting nut can connect and secure the connecting shaft and set screw.

[0016] In another embodiment of the battery pack of the present disclosure, the connecting nut is arranged so that the first screw hole and the second screw hole are not connected to each other, and is provided with a waterproof gasket arranged between the inner surface of the first lid portion and the end face of the connecting nut, and a set screw is screwed into the second screw hole, and the waterproof gasket is sandwiched between the inner surface of the first lid portion and the end face of the connecting nut, allowing the set screw to penetrate the first lid portion in a waterproof structure.

[0017] The battery pack described above has a simple structure and is characterized by the ability to pass a set screw through the first lid and connect it to the connecting nut in a waterproof configuration. The set screw, which passes through the first lid and threads into the second threaded hole in the connecting nut, sandwiches a waterproof gasket between the inner surface of the first lid and the end face of the connecting nut, preventing water from entering the first lid. For example, as shown in the enlarged cross-sectional view of Figure 6, the first threaded hole 24a and the second threaded hole 24b at both ends of the connecting nut 23 are not connected to each other, preventing water from entering the interior along the set screw 25 indicated by arrow B. This simple structure, in which waterproof gasket 30 is used to waterproof the gap between the end face 23a of the connecting nut 23 and the inner surface 42a of the first lid 42, prevents water from entering in the direction indicated by arrow A. The inner surface 42a of the first lid 42 and the end face 23a of the connecting nut 23 are reliably waterproofed by sandwiching the ring-shaped waterproof gasket 30. In particular, this structure has the advantage of being able to more reliably waterproof, since the set screw 25 can be screwed into the second screw hole 24b of the connecting nut 23 and the inner surface 42a of the first lid portion 42 can be pressed against the end surface 23a of the connecting nut 23 to clamp the waterproof gasket 30.

[0018] A battery pack according to another embodiment of the present disclosure includes a waterproof gasket disposed between the head of a set screw and the outer surface of the first lid. When the set screw is threaded into the second screw hole, the waterproof gasket is sandwiched between the head of the set screw and the outer surface of the first lid, allowing the set screw to penetrate the first lid in a waterproof structure. This battery pack has the advantage of being able to waterproof the set screw that penetrates the first lid with a simple structure. This is because, for example, as shown in the enlarged cross-sectional view of Figure 7, waterproof gasket 30 is disposed between head 25a of set screw 25 and outer surface 42b of first lid 42, preventing water from entering in the directions indicated by arrows A and B.

[0019] In another embodiment of the battery pack according to the present disclosure, the core pack has a nut recess on its end surface that guides the connecting nut in a non-rotating state, and a connecting shaft is threaded into a first threaded hole in the connecting nut, guided by the nut recess, thereby securing multiple battery blocks in a stacked state. This battery pack can be connected to the core pack without rotating the connecting nut, which has the advantage that multiple battery blocks can be securely secured in a stacked state by rotating the connecting shaft and securely threading it into the first threaded hole in the connecting nut. Another advantage is that the first lid can be secured to the core pack by rotating the set screw and securely threading it into the second threaded hole in the connecting nut. Furthermore, by securing the set screw to a metal connecting nut rather than directly to a resin portion of the core pack, and by providing a nut recess on the end surface of the core pack to guide the connecting nut in a non-rotating state, the threaded portion does not loosen when the battery pack is vibrated, and the plastic in the threaded portion does not crack and break when the battery pack is dropped, ensuring high earthquake resistance and drop impact resistance.

[0020] In another embodiment of the battery pack according to the present disclosure, the connecting nut has a non-circular outer periphery, and the nut recess has an internal recess that guides the non-circular connecting nut in a non-rotating state. This battery pack can be connected to the core pack without rotating the connecting nut, which allows multiple battery blocks to be securely secured in a stacked state by rotating the connecting shaft and securely threading it into the first threaded hole of the connecting nut. Another advantage is that the first lid can be secured to the core pack by rotating the set screw and securely threading it into the second threaded hole of the connecting nut. Furthermore, by securing the set screw to the metal connecting nut rather than directly to the resin portion of the core pack, and by providing a nut recess on the end face of the core pack to guide the connecting nut in a non-rotating state, the battery pack can be secured to a high level of earthquake resistance and drop impact resistance, without loosening the threaded portion when the battery pack is vibrated or cracking the plastic at the threaded portion when the battery pack is dropped.

[0021] In a battery pack according to another embodiment of the present disclosure, the head of the connecting shaft can contact and clamp the end face of the core pack. This battery pack has the advantage that the core pack can be clamped between the connecting nut and the head of the connecting shaft threaded into the connecting nut, thereby reliably securing multiple battery blocks in a stacked state. This battery pack has the advantage that, when multiple battery blocks are stacked, the connecting shaft can be inserted into the multiple battery blocks and threaded into the first screw hole of the connecting nut, thereby clamping the core pack between the connecting nut and the head of the connecting shaft, thereby reliably securing multiple battery blocks in a stacked state.

[0022] A battery pack according to another embodiment of the present disclosure includes a spacer portion disposed between the end of the core pack and the head of the connecting shaft, and the head of the connecting shaft presses against the end face of the core pack via the spacer portion, thereby securing multiple battery blocks in a stacked state. The battery pack described above has the advantage that the connecting shaft, which is threaded into the connecting nut, clamps the core pack via the spacer portion, securing multiple battery blocks in a stacked state, thereby providing space at the end of the core pack for arranging, for example, a circuit board, and securing multiple battery blocks in a stacked state.

[0023] 1 to 6 show a battery pack 100 according to one embodiment of the present disclosure. The battery pack 100 shown in these figures houses a battery core pack 10, which is made up of a plurality of stacked battery blocks 3, in an exterior case 40. In the battery core pack 10, the plurality of battery blocks 3 are stacked in the lengthwise direction, which is the longitudinal direction of the battery cells 1, and connected linearly. The exterior case 40 and the core pack 10 are connected by a fixing portion 20.

[0024] The battery pack 100 of the present disclosure is attached to, for example, an electric vehicle to supply power to a drive motor. The battery pack 100 can be used as a power source for, for example, an electric motorcycle, an electric-assisted bicycle, an electric wheelchair, an electric tricycle, an electric cart, etc. However, the present disclosure does not specify the use of the battery pack 100, and the battery pack 100 can be used as a power source for various electrical devices used outdoors, such as power tools.

[0025] [Battery Block 3] As shown in the perspective view of FIG. 3 , the battery block 3 is a cylindrical battery 1A in which multiple rechargeable battery cells 1 are arranged in a parallel position. The battery block 3 of the cylindrical battery 1A in the figure is arranged in multiple rows and columns in a parallel position, with through holes 11 for inserting connecting shafts 21 between the battery cells 1. The battery cells 1 are rechargeable secondary batteries, and lithium-ion secondary batteries can be used. However, this disclosure does not limit the battery cells 1 to lithium-ion batteries; all other rechargeable secondary batteries can be used, including currently used batteries such as lithium polymer secondary batteries and all-solid-state batteries to be developed in the future. Furthermore, although the battery pack 100 in FIGS. 3 and 5 uses cylindrical batteries 1A as the battery cells 1, the battery cells 1 can also be batteries other than cylindrical batteries 1A, such as prismatic batteries.

[0026] The battery block 3 has multiple battery cells 1 arranged in parallel with their longitudinal directions facing in the same direction. The battery block 3 connects the multiple battery cells 1 in parallel or in series with lead plates. The battery block 3 can be divided into parallel units by connecting multiple battery cells 1 in parallel. This battery block 3 can increase the output voltage by connecting multiple parallel units in series.

[0027] The battery block 3 is equipped with battery holders 4 that hold the battery cells 1 in fixed positions. The battery holders 4 hold the multiple battery cells 1 that make up the battery block 3 in fixed positions. The battery holders 4 are made of a material with excellent insulating properties, preferably a thermoplastic plastic. The battery holders 4 hold each battery cell 1 in a parallel position, with the end faces of the battery cells 1 positioned on the same plane.

[0028] The battery holder 4 has multiple cell retention openings 5 ​​into which battery cells 1 are inserted and held. Each cell retention opening 5 has an interior shape that follows almost the entire periphery of the surface of the battery cell 1. The battery holder 4 holds multiple battery cells 1 in predetermined positions by inserting a battery cell 1 into each cell retention opening 5.

[0029] The battery holder 4 in Figure 3 is made up of a pair of cell holders 4A, 4B that are split in half at the middle of the battery cell 1. The pair of cell holders 4A, 4B split the cell retention opening 5 in half at the center of each battery cell 1. The two cell holders 4A, 4B are connected via the battery cell 1 so that their relative positions do not shift, with both ends of the battery cell 1 inserted into the cell retention opening 5.

[0030] Furthermore, the battery holder 4 is provided with a through-hole 11 for inserting the connecting shaft 21. This through-hole 11 is located in the center of the battery holder 4, between the cell holding openings 5. This battery holder 4 can be provided with the through-hole 11 while effectively utilizing the space between the cell holding openings 5. As shown in FIG. 5 , the battery holder 4 can be provided with a through-hole 11 in its center, utilizing the gap between adjacent cylindrical batteries 1A. One or more through-holes 11 can be provided. The through-holes 11 in FIG. 5 are located at two separate locations in the center of the battery holder 4, efficiently improving the fastening strength of the core pack 10. The battery holder 4 of the battery block 3 is provided with a through-hole 11 that penetrates from one end face 3a to the other end face, and a nut recess 12 can be provided on one of the end faces 3a that communicates with the through-hole 11. Furthermore, a recess can be provided on the end face 3a opposite the nut recess 12 for accommodating the head 22 of the connecting shaft 21. This battery holder 4 can share a common shape and components, and by stacking these battery blocks 3 without misalignment, linear through-holes 11 are formed in the stacked battery blocks 3, allowing connecting shafts 21 to be inserted into the through-holes 11 and fastened to connecting nuts 23.

[0031] The pair of cell holders 4A, 4B, which are molded separately, can be connected with a locking structure to prevent misalignment and straighten the through holes 11 of the stacked battery blocks 3. However, the two separate cell holders can also be connected with a connecting structure other than a locking structure, for example, by screwing or gluing.

[0032] Although the battery holder 4 described above is molded from plastic and divided into two parts in the middle of the battery cell 1, the battery pack 100 of the present disclosure does not limit the battery holder 4 to this structure. The battery holder 4 can have any other structure that can hold multiple battery cells 1 in place. For example, the battery holder 4 can be an integrated structure without being divided, a structure divided into three or more parts, divided into different positions, or a structure closed with a lid.

[0033] Furthermore, the battery holder 4 can have an interlocking structure on the opposing surfaces when stacked to connect the stacked battery blocks 3 without misalignment. Interlocking battery blocks 3 have an interlocking protrusion on one end surface 3a and an interlocking recess on the other end surface 3a. These battery blocks 3 can be stacked without misalignment by guiding the interlocking protrusion into the interlocking recess.

[0034] [Core Pack 10] The core pack 10 has multiple battery blocks stacked in a linear fashion. The core pack 10 in Figure 2 has multiple battery blocks 3 secured in a stacked state by fastening parts 20 and arranged in a long, slender linear fashion. In the core pack 10, the battery blocks 3 are stacked in a linear fashion with the longitudinal directions of the battery cells 1 parallel to one another. The core pack 10 secures the multiple battery blocks 3 with fastening parts 20. The fastening parts 20 secure the multiple stacked battery blocks 3 by having connecting shafts 21 inserted into the stacked battery blocks 3 threaded into connecting nuts 23, sandwiching the connecting nuts 23 and the heads 22 of the connecting shafts 21 to secure the battery blocks 3 in a stacked state. The core pack 10 in Figure 5 has two rows of through holes 11 in each battery block 3, and the battery blocks 3 are secured in a stacked state with two connecting shafts 21. Adjacent battery blocks 3 secured in a stacked state are connected in series or parallel via lead plates.

[0035] The core pack 10 has a through hole 11 into which a connecting shaft 21 is inserted. The through hole 11 extends in the longitudinal direction of the core pack 10, which linearly stacks multiple battery blocks parallel to the battery cells 1. The through hole 11 in Figure 4 extends parallel to the battery cells 1 and is provided in the battery holder 4 between the battery cells 1. The through hole 11 communicates with a nut recess 12 into which a connecting nut 23 is inserted, and the through hole 11 and nut recess 12 pass linearly through the core pack 10 in the longitudinal direction. The connecting shaft 21 inserted into the through hole 11 is fastened to the connecting nut 23 inserted into the nut recess 12, securing the multiple battery blocks 3 in a stacked state.

[0036] The core pack 10 has a nut recess 12 on one end surface 10a into which the connecting nut 23 is inserted. The nut recess 12 is preferably shaped so that the connecting nut 23 can be guided and inserted without rotation. For example, a hexagonal outer shaped connecting nut 23 can be inserted into the nut recess 12 with a hexagonal inner shape, allowing the connecting nut 23 to be inserted without rotation. The nut recess 12, which guides the connecting nut 23 in a non-rotating, i.e., non-rotating, state, allows the connecting shaft 21 and set screw 25 to be easily and reliably threaded onto the connecting nut 23. This is because the connecting nut 23 does not rotate with the connecting shaft 21 or set screw 25 when threaded into the connecting nut 23. The structure for guiding the connecting nut 23 into the nut recess 12 without rotation can be achieved by making the outer shape of the connecting nut 23 non-cylindrical and guiding the non-cylindrical connecting nut 23 into the nut recess 12.

[0037] The nut recess 12, which guides the connecting nut 23 in a non-rotating state, allows the connecting shaft 21 and set screw 25 to be threaded in reliably, but the nut recess 12 does not necessarily have to guide the connecting nut 23 in a non-rotating state. This is because, when the connecting shaft 21 is threaded onto the connecting nut 23, the connecting nut 23 can be gripped to prevent rotation and the connecting shaft 21 can be threaded in. Also, when the set screw 25 or connecting shaft 21 is threaded onto the connecting nut 23, the connecting nut 23 is pressed against the inner surface of the nut recess 12 by the connecting shaft 21 or set screw 25, preventing it from rotating due to frictional resistance.

[0038] 6 is configured such that the length (L1) of the nut recess 12 is shorter (shallower) than the length (L2) of the connecting nut 23, and the end face 23a of the connecting nut 23 inserted into the nut recess 12 protrudes from the end face 3a (end face 10a of the core pack 10) of the battery block 3. This configuration has the advantage that, when the set screw 25 is threaded into the connecting nut 23, the waterproof gasket 30 is sandwiched between the end face 23a of the connecting nut 23 and the inner surface 42a of the first lid portion 42, ensuring reliable waterproofing. However, the waterproof structure between the set screw 25 and the first lid portion 42 can also be achieved by sandwiching a waterproof gasket 30 between the head 25a of the set screw 25 and the outer surface 42b of the first lid portion 42, as shown in Figure 7.This structure can be such that the end face 23a of the connecting nut 23 and the end face 3a of the battery block 3 are on the same plane, or the end face 3a of the battery block 3 protrudes from the end face 23a of the connecting nut 23.

[0039] The battery core pack 10 shown in Figures 2 and 3 has four battery blocks 3 stacked linearly with the longitudinal direction of each battery cell 1 aligned. The stacked battery blocks 3 can be connected in series or parallel by connecting lead plates to the surface electrodes 2 exposed on the surface of the core pack 10. The lead plates can be connected to the surface electrodes 2 of adjacent battery blocks 3 by soldering, laser welding, spot welding, or other methods, with connecting shafts 21 screwed into connecting nuts 23 to secure the multiple battery blocks 3 in a stacked state. The lead plates connected to the surface electrodes 2 also function to hold the stacked battery blocks 3 in place.

[0040] 2 and 3 have four battery blocks 3 connected in a linear fashion, the present disclosure does not limit the total number of battery blocks 3 constituting the battery core pack 10 to four. Although not shown, the battery core pack 10 can also have five or more battery blocks 3, or three or fewer. In this core pack 10, lead plates can be connected to the surface electrodes 2 of adjacent battery blocks 3 to connect the battery blocks 3 in series or parallel.

[0041] [Outer Case 40] The outer case 40 includes an outer tube 41 that houses the core pack 10, a first lid 42 that closes a first end 41A of the outer tube 41, and a second lid 44 that closes a second end 41B of the outer tube 41. The outer case 40 is preferably made of a metal such as aluminum. A metal outer case 40 has excellent strength and heat dissipation characteristics. However, the outer case 40 does not necessarily have to be made of metal, and can also be molded from a sufficiently strong material such as polycarbonate.

[0042] The inner shape of the outer tube portion 41 is slightly larger than the outer shape of the core pack 10, allowing for smooth insertion of the core pack 10. The outer tube portion 41 is molded to have an inner shape that allows the outer surface of the inserted core pack 10 to make surface contact with the inner surface. This outer tube portion 41 positions the core pack 10 in a fixed position, suppresses vibration and movement, and increases impact resistance. It also has the advantage of maintaining a favorable thermal bond between the outer tube portion 41 and the core pack 10, allowing for efficient dissipation of heat generated by the core pack 10 to the outside.

[0043] 4, the outer case 40 has a first end 41A of an outer tube 41 closed by a first lid 42 and a second end 41B closed by a second lid 44. The first end 41A is provided with a protrusion 45 that protrudes from the surface of the first lid 42, improving drop impact resistance when the device is dropped with the first lid 42 facing downwards. The protrusion 45 prevents the set screw 25 from colliding with the ground and being damaged when dropped, and also absorbs impact.

[0044] While the present disclosure is not limited to a battery pack having a waterproof exterior case 40, a battery pack 100 having a waterproof exterior case 40 has the advantage of being safe for use in outdoor devices, such as electric motorcycles and electric bicycles. While the present disclosure is not limited to a specific waterproof structure, for example, a battery pack 100 having a waterproof exterior case 40 has a first lid portion 42 and a second lid portion 44 connected to an outer tube portion 41 in a waterproof structure. Figures 8 to 10 show partially enlarged cross-sectional views illustrating the waterproof connection between the outer tube portion 41 and the first lid portion 42. The first lid portion 42 shown in Figure 8 has a connecting tube 43 on its outer periphery that is inserted into the inner surface 41a of the outer tube portion 41. This shape of the first lid portion 42 can be manufactured by stamping or spinning a single metal plate such as aluminum. The connecting tube 43 includes a press-fit tube 43a that fits tightly against the inner surface 41a of the outer tube portion 41, and a pressure tube 43b that presses the waterproof ring 31 against the inner surface 41a of the outer tube portion 41 to create a waterproof structure. The press-fit tube 43a is cylindrical and presses into the outer tube portion 41 to fit snugly against the inner surface 41a of the outer tube portion 41, while the pressure tube 43b sandwiches the waterproof ring 31 between the press-fit tube 43a and the inner surface 41a of the outer tube portion 41, creating a waterproof structure between the press-fit tube 43a and the outer tube portion 41. The first cover 42 shown in FIG. 8 is press-fitted into the first end 41A of the outer tube portion 41 while sandwiching the waterproof ring 31, thereby sealing the first end 41A of the outer tube portion 41 in a waterproof structure. As shown in FIG. 8, the connecting tube 43 can be press-fitted into the inside of the outer tube portion 41 to secure the first cover 42. In the connecting tube 43 of this structure, the outer shape of the press-fit tube 43a is slightly larger than the inner shape of the outer tube portion 41, and in the press-fit state, the outer surface of the press-fit tube 43a presses against the inner surface 41a of the outer tube portion 41, thereby reliably connecting the first lid portion 42 to the outer tube portion 41. Furthermore, as shown in Figure 9, the press-fit tube 43a and the outer tube portion 41 can be fixed by spot welding 46, or as shown in Figure 10, the press-fit tube 43a and the outer tube portion 41 can be fixed by rivets 47, thereby more reliably fixing the first lid portion 42 and the outer tube portion 41.

[0045] As shown in the cross-sectional view of FIG. 11 , the second lid portion 44 has a ring-shaped peripheral wall 44b formed around the outer periphery of a flat plate 44a, and the flat plate 44a and the peripheral wall 44b are molded as an integral structure. A board holder 7 housing a circuit board 6 is fixed to the core pack 10 by screws in an internal space on the second end 41B side of the outer tube portion 41 formed between the second lid portion 44 and the core pack 10. The second lid portion 44 is preferably made of the same material as the outer tube portion 41 and the first lid portion 42. Therefore, for an exterior case 40 in which the outer tube portion 41 and the first lid portion 42 are made of aluminum, the second lid portion 44 is also made of aluminum. However, the second lid portion 44 does not necessarily have to be made of the same material as the outer tube portion 41. For example, the outer tube portion 41 could be made of aluminum and the second lid portion 44 could be made of plastic.

[0046] The second lid 44 can waterproofly close the second end 41B of the outer tube 41. The second lid 44 shown in the cross-sectional view of FIG. 11 waterproofly closes the second end 41B of the outer tube 41 via a waterproof ring 32. The second lid 44 in the figure has an integral peripheral wall 44b that protrudes parallel to the inner circumferential surface of the outer tube 41. The waterproof ring 32 is sandwiched between the inner circumferential surface of the second end 41B of the outer tube 41 and the peripheral wall 44b, enabling the second lid 44 to be waterproofly closed. The waterproof ring 32 can be made of a rubber-like elastic body shaped to match the inner circumferential surfaces and peripheral walls 44b on both sides to which it is sandwiched. The waterproof ring 32 can have multiple rows of ridges on its outer circumferential surface. The ridged waterproof ring 32 can be guided into a ring groove on the inner circumferential surface of the second end 41B of the outer tube 41 to achieve more reliable waterproofing. The second lid portion 44 can have a step portion on the outer peripheral surface of the peripheral wall 44b to guide the waterproof ring 32, and with the waterproof ring 32 inserted into the inner peripheral surface of the second end portion 41B, the peripheral wall 44b of the second lid portion 44 can be pressed into the waterproof ring 32 to close the second end portion 41B in a waterproof structure.

[0047] [Fixing section 20] The fixing section 20 includes a connecting shaft 21 that connects multiple battery blocks 3 in the longitudinal direction, a connecting nut 23 that is connected to the end of the connecting shaft 21, and a set screw 25 that is connected to the connecting nut. In the fixing section 20 shown in Figure 4, the connecting shaft 21, connecting nut 23, and set screw 25 are arranged in a straight line, and the set screw 25 is located on an extension of the connecting shaft 21 and connecting nut 23. The connecting shaft 21 is inserted into the through hole 11 and fastened to the connecting nut 23 to fix the multiple battery blocks 3 in the longitudinal direction. The set screw 25 passes through the first lid section 42 and fastens to the connecting nut 23 to fix the first lid section 42 to the core pack 10 in which multiple battery blocks 3 are stacked.

[0048] [Connecting Shaft 21] The connecting shaft 21 has a threaded portion 21a at its tip that is inserted into the through-hole 11. The threaded portion 21a is sufficient as long as it can be threaded into the second screw hole 24b of the connecting nut 23 for fastening. For example, the connecting shaft 21 can be one that has the threaded portion 21a at its tip, a half-threaded thread, a full-threaded thread, or a long-threaded thread. The connecting shaft 21 has a length that allows it to be fastened from the insertion-side opening on one end face of the core pack 10 to the connecting nut 23 located on the other end face. The connecting shaft 21 is inserted into the stacked battery blocks 3, and the threaded portion 21a at its tip is threaded into the connecting nut 23, securing the stacked battery blocks 3 together. When the connecting shaft 21 is threaded into the connecting nut 23, the connecting nut 23 and the head 22 of the connecting shaft 21 clamp both ends of the core pack 10, securing the stacked battery blocks 3 together to form the core pack 10. The head 22 of the connecting shaft 21 has a non-circular outer shape such as a hexagon, or has a + or - groove formed in it so that the connecting shaft 21 can be rotated and screwed into the connecting nut 23. The head 22 includes not only a screw head that is integral with the shaft portion, but also a nut screwed onto the thread of the shaft portion.

[0049] [Connecting Nut 23] The connecting nut 23 has a first threaded hole 24a at one end, into which the threaded portion 21a of the connecting shaft 21 is threaded, and a second threaded hole 24b at the other end, into which a set screw 25 is threaded. In the connecting nut 23 shown in Figure 6, the first threaded hole 24a and the second threaded hole 24b are arranged so that they do not communicate with each other. This connecting nut 23 can be manufactured by drilling a female threaded hole from one end face 23a (the right end face 23a in Figure 6) to form the first threaded hole 24a, and drilling a female threaded hole from the other end face 23a (the left end face 23a in Figure 6) to a position where it does not penetrate the first threaded hole 24a, into the second threaded hole 24b. The connecting nut 23, in which the first screw hole 24a and the second screw hole 24b do not communicate with each other, can easily and reliably waterproof the first screw hole 24a and the second screw hole 24b, and as shown by arrow B in Figure 6, it can prevent water that enters along the set screw 25 (first screw hole 24a) that secures the first lid portion 42 from entering the second screw hole 24b, which has the advantage of simplifying the waterproof structure.

[0050] However, since the battery pack 100 can also achieve a waterproof structure for the outer case 40 by using a connecting nut 23 in which the first screw hole 24a and the second screw hole 24b are connected, the connecting nut 23 can also be configured in such a way that the first screw hole 24a and the second screw hole 24b are connected.

[0051] The connecting nut 23 enables fastening to the connecting shaft 21 and fastening between the first lid portion 42 of the outer case 40 and the core pack 10 using a single, common member, and connects the connecting shaft 21 and the set screw 25, which are each screw-fastened to the connecting nut 23. The connecting nut 23 is a nut for forming the core pack 10, which secures multiple battery blocks 3 in a stacked state to form the core pack 10, and also a nut for fastening the first lid portion 42 and the core pack 10. The connecting nut 23 can screw-fasten both the connecting shaft 21 and the set screw 25, eliminating the need for separate components (such as nuts) to fasten the connecting shaft 21 and the set screw 25, and naturally eliminating the need to further fasten items that are already fastened with separate nuts, thereby reducing the number of parts, reducing and / or simplifying the manufacturing process, and reducing costs.

[0052] The connecting nut 23 has the first screw hole 24a and the second screw hole 24b arranged in a straight line, thereby increasing the connection strength between the core pack 10 and the outer case 40. The connecting shaft 21 and the set screw 25 can be connected in a straight line via the connecting nut 23. The connecting nut 23 and the connecting shaft 21 can be fastened together, and the set screw 25 can fasten the first lid portion 42 and the core pack 10 in a straight line. Because the connecting shaft 21 and the set screw 25 are fastened to the connecting nut 23 in a straight line (opposite directions), the fastening strength can be reflected in the connection strength without loss. For example, when screws in different directions are fastened with nuts made of separate components and then fastened together, the strength of the battery pack 100 can be improved compared to, for example, when the outer case and the core pack are fastened together with a set screw perpendicular to the connecting shaft. The connecting nut 23 also fastens the connecting shaft 21 to form the core pack 10, and further enables secure fastening with the set screw 25 when securing the first lid portion 42 to the core pack 10, improving the earthquake resistance and drop impact resistance of the battery pack 100. By firmly connecting multiple battery cells 1 in a stacked state and firmly connecting the first lid portion 42 of the exterior case 40 to the core pack 10, the battery pack 100 can achieve high earthquake resistance and drop impact resistance against vibration, dropping, and the like. Because the connecting shaft 21, connecting nut 23, and set screw 25 are all made of metal, they can be connected and secured with sufficient strength by fastening each screw. Fastening the connecting shaft 21 to the connecting nut 23 securely connects and secures multiple battery blocks 3 in a stacked state to form the core pack 10. Furthermore, by passing the set screw 25 through the first lid portion 42 and fastening it to the connecting nut 23, the first lid portion 42 can be securely connected and secured to the core pack 10.

[0053] [Set screw 25] The set screw 25 passes through the first lid portion 42 and is threaded into the second screw hole 24b of the connecting nut 23 to secure the first lid portion 42 to the core pack 10. The connecting nut 23 in FIG. 4 connects the connecting shaft 21 and the set screw 25. In this battery pack 100, the first lid portion 42 of the outer case 40 can be connected more firmly to the core pack 10 than when the connecting shaft 21 and the set screw 25 are not connected (e.g., as shown in FIG. 11 ). By firmly connecting the core pack 10 and the first lid portion 42 on the end face of the outer case 40, the battery pack 100 can achieve high earthquake resistance and drop impact resistance.

[0054] The core pack 10 is sandwiched between a connecting nut 23 at one end (end surface 10a) and a connecting shaft 21 that is threaded into a first screw hole 24a of the connecting nut 23 at the other end (end surface 10a), thereby securing multiple battery blocks 3 in a stacked state. The head 22 of the connecting shaft 21 directly or indirectly presses against the other end (end surface 10a) of the core pack 10 to sandwich it. The connecting shaft 21 in FIG. 11 is sandwiched by the head 22 contacting the end surface 10a of the core pack 10. As shown in FIG. 11 , the end surface 10a of the core pack 10 can be provided with a recess in which the head 22 of the connecting shaft 21 is disposed. The head 22 of the connecting shaft 21 presses against the end surface 10a of the core pack 10 in the recess.

[0055] 12 has a spacer portion 26 disposed between the end face 10a of the core pack 10 and the head portion 22 of the connecting shaft 21. In this battery pack 100, the head portion 22 of the connecting shaft 21, which is threaded into the connecting nut 23, presses against the end face 10a of the core pack 10 via the spacer portion 26, securing multiple battery blocks 3 in a stacked state, and the height of the spacer portion 26 can be used to provide space at the end of the core pack 10 for arranging, for example, a circuit board, wiring, etc.

[0056] The above battery pack 100 can be assembled, for example, by the following steps: (1) Stacking multiple battery blocks 3 and inserting connecting shafts 21 into the through-holes 11 of the stacked battery blocks 3 (core packs 10). (2) Guide connecting nuts 23 into the nut recesses 12 on the end faces 3a of the stacked battery blocks 3, and thread the connecting shafts 21 into the first screw holes 24a of the connecting nuts 23 in the nut recesses 12 to secure the stacked battery blocks 3 together with the connecting shafts 21 and connecting nuts 23. In this state, the core packs 10 are sandwiched between the heads 22 of the connecting shafts 21 and the connecting nuts 23 and secured in a stacked state. (3) Electrically connect lead plates to the surface electrodes 2 of adjacent battery blocks 3 by soldering or other methods. (4) After arranging necessary components such as a circuit board on one end of the core pack 10, i.e., the end where the heads 22 of the connecting shafts 21 are exposed, insert the core pack 10 into the outer tube portion 41 of the exterior case 40. (5) The core pack 10 is fixed to the first lid 42 by threading a set screw 25 that passes through the first lid 42 into the second screw hole 24b of the connecting nut 23 on the end surface 10a of the core pack 10 inserted into the outer tubular portion 41. In a battery pack 100 in which the set screw 25 passes through the first lid 42 in a waterproof structure, a waterproof gasket 30 is sandwiched between the inner surface 42a of the first lid 42 and the end surface 23a of the connecting nut 23, and the set screw 25 is threaded into the connecting nut 23 to connect the first lid 42 to the core pack 10, as shown in Fig. 6, for example. (6) In a battery pack 100 in which the exterior case 40 is waterproof, the first lid 42 is fixed to the first end 41A of the outer tubular portion 41 to close the first end 41A in a waterproof structure. A second lid portion 44 is fixed to the second end portion 41B of the outer tube portion 41 to close the second end portion 41B in a waterproof structure.

[0057] The battery pack 100 is provided with a connector (not shown) that can output power to the outside or communicate with a device in which the battery pack 100 is installed. This connector can be fixed to the second lid portion 44 in a waterproof structure, for example. A battery pack 100 with a connector fixed to the second lid portion 44 can be manufactured by connecting the connector via lead wires to the core pack 10 or circuit board inserted into the outer tubular portion 41, fixing this connector to the second lid portion 44, and closing the second end 41B of the outer tubular portion 41 with the second lid portion 44 to which the connector is fixed. However, the battery pack 100 of the present disclosure does not specify the structure or method for fixing the connector, and the structure and method for fixing the connector can be the structure and method of a conventional battery pack.

[0058] The present disclosure can be effectively used as a battery pack that can simply, easily, and firmly connect a core pack and an outer case to increase impact resistance.

[0059] 100, 900... Battery pack 1... Battery cell 1A... Cylindrical battery 2... Surface electrode 3... Battery block 3a... End surface (of battery block) 4... Battery holder 4A, 4B... Cell holder 5... Cell holding opening 6... Circuit board 7... Board holder 10... Core pack 10a... End surface (of core pack) 11... Through hole 12... Nut recess 20... Fixing portion 21... Connecting shaft 21a... Threaded portion 22... Head (of connecting shaft) 23... Connecting nut 23a... End surface (of connecting nut) 24a... First screw hole 24b... Second screw hole 25... Set screw 25a... Head (of set screw) 26... Spacer portion 30... Waterproof packing 31, 32... Waterproof ring 40... Outer case 41... Outer tube portion 41a... Inner surface (of outer tube portion) 41A... First end 41B... Second end 42... First lid portion 42a... Inner surface 42b... Outer surface 43... Connecting tube 43a... Press-fitting tube 43b... Pressing tube 44... Second lid portion 44a... Flat plate 44b... Peripheral wall 45... Protrusion 46... Spot welding 47... Rivet 903... Battery block 904... Battery holder 910... Core pack 921... Connecting shaft 925... Set screw 940... Outer case 941... Cylinder portion 942, 944... Lid portion

Claims

1. The battery pack includes a core pack in which a plurality of battery blocks are linearly connected, an exterior case that houses the core pack, and a fixing portion that connects the exterior case to the core pack. The exterior case includes an outer cylinder portion that houses the core pack, a first lid portion that closes a first end of the outer cylinder portion, and a second lid portion that closes a second end. The fixing portion includes a connecting shaft that connects the plurality of battery blocks in the longitudinal direction, a connecting nut connected to an end of the connecting shaft, and a set screw that passes through the first lid portion of the exterior case and is connected to the connecting nut. The connecting shaft includes a threaded portion that is inserted into the plurality of battery blocks. The connecting nut is provided with a first threaded hole into which the threaded portion of the connecting shaft is screwed at one end and a second threaded hole into which the set screw is screwed at the other end. The core pack is sandwiched between the connecting nut and the connecting shaft screwed into the first threaded hole of the connecting nut to fix the plurality of battery blocks in a stacked state. The set screw passes through the first lid portion and is screwed into the second threaded hole of the connecting nut to fix the first lid portion of the exterior case to the core pack.

2. The battery pack according to claim 1, wherein the connecting nut is arranged such that the first threaded hole and the second threaded hole do not communicate with each other, and includes a first waterproof packing arranged between an inner surface of the first lid portion and an end surface of the connecting nut. The set screw is screwed into the second threaded hole, and the inner surface of the first lid portion and the end surface of the connecting nut sandwich the first waterproof packing, and the set screw penetrates the first lid portion with a waterproof structure.

3. The battery pack according to claim 1, further comprising a second waterproof packing arranged between a head of the set screw and an outer surface of the first lid portion. The set screw is screwed into the second threaded hole, and the head of the set screw and the outer surface of the first lid portion sandwich the second waterproof packing, and the set screw penetrates the first lid portion with a waterproof structure.

4. The battery pack according to claim 1, wherein the core pack is provided with a nut recess on an end face for guiding the connecting nut in a non-rotating state, and the connecting shaft is screwed into the first screw hole of the connecting nut guided in the nut recess, and a plurality of the battery blocks are fixed in a stacked state.

5. The battery pack according to claim 4, wherein the connecting nut is a nut having a non-circular outer periphery, and the nut recess is an inner-shaped recess for guiding the non-circular connecting nut in a non-rotating state.

6. The battery pack according to any one of claims 1 to 5, wherein the head of the connecting shaft contacts and sandwiches the end face of the core pack.

7. The battery pack according to claim 1, further comprising a spacer portion disposed between an end of the core pack and the head of the connecting shaft, and the head of the connecting shaft presses the end face of the core pack via the spacer portion, and a plurality of the battery blocks are fixed in a stacked state.

8. The battery pack includes a core pack that linearly connects a plurality of battery blocks, an exterior case that houses the core pack, and a fixing portion that connects the exterior case to the core pack. The exterior case includes an outer cylinder portion that houses the core pack, a first lid portion that closes a first end of the outer cylinder portion, and a second lid portion that closes a second end. The fixing portion includes a connecting shaft that connects the plurality of battery blocks, a connecting nut that is connected to an end of the connecting shaft, and a set screw that passes through the first lid portion of the exterior case and is connected to the connecting nut. The connecting shaft includes a threaded portion that is inserted into the plurality of battery blocks. The connecting nut includes a first threaded hole and a second threaded hole at both ends. The threaded portion is screwed into the first threaded hole, and the set screw is screwed into the second threaded hole. The core pack is sandwiched between the connecting nut and the connecting shaft screwed into the first threaded hole of the connecting nut, and fixes the plurality of battery blocks in a stacked state. The set screw passes through the first lid portion and is screwed into the second threaded hole of the connecting nut, and fixes the first lid portion of the exterior case to the core pack.

9. The battery pack according to claim 8, wherein the connecting nut includes a first waterproof packing disposed between an inner surface of the first lid portion and an end surface of the connecting nut without the first threaded hole and the second threaded hole communicating with each other.

10. The battery pack according to claim 9, wherein the set screw is screwed into the second threaded hole, and the inner surface of the first lid portion and the end surface of the connecting nut sandwich and fix the first waterproof packing.

11. The battery pack according to claim 8, further comprising a second waterproof packing disposed between a head of the set screw and an outer surface of the first lid portion.

12. The battery pack according to claim 8, wherein the core pack is provided with a nut recess on an end surface that guides the connecting nut in a non-rotating state.

13. The battery pack according to claim 12, wherein the connecting nut is a nut having a non-circular outer periphery, and the nut recess is an inner-shaped recess that guides the non-circular connecting nut in a non-rotating state.

14. The battery pack according to any one of claims 8 to 12, wherein the head of the connecting shaft contacts the end face of the core pack, and the plurality of battery blocks are sandwiched and fixed in a stacked state by the connecting nut and the head of the connecting shaft.

15. The battery pack according to claim 8, further comprising a spacer portion disposed between an end portion of the core pack and the head of the connecting shaft, wherein the head of the connecting shaft presses the end face of the core pack via the spacer portion, and a plurality of the battery blocks are fixed in a stacked state.

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