Battery pack

Abstract

According to the present invention, a core block housed within an outer case is effectively prevented from moving relative to the outer case. A main cylinder part is formed to be thin and light at a low cost, and openings at both ends of the main cylinder part are precisely covered with covering parts.　This battery pack comprises a core block (10) composed of a plurality of battery blocks (9) that are stacked and interconnected, the battery blocks (9) being composed of a plurality of battery cells (1) arranged at fixed positions of a battery holder, an outer case (3) provided with a cylindrical main cylinder part (4) into which the core block (10) is inserted and a pair of covering parts (5) that cover openings at both ends of the main cylinder part (4), and a fastening member (6) that fastens the pair of covering parts (5) and clamps the main cylinder part (4) from both sides with the pair of covering parts (5). The core block (10) is housed within the outer case (3) at such an orientation that the plurality of the battery blocks (9) are stacked in the axial direction of the main cylinder part (4), and the fastening member (6) fastens the pair of covering parts (5) with the core block (10) interposed therebetween.

Description

[Technical Field]

[0001] The present invention relates to a battery pack in which a core block is housed in an exterior case and is made up of a plurality of stacked and connected battery blocks, each of which has a plurality of battery cells arranged in fixed positions in a battery holder. [Background technology]

[0002] Battery packs with multiple battery cells connected in series and parallel are used for applications requiring high output, such as electric bicycles and assisted bicycles. This battery pack can increase the output voltage (V) by increasing the number of cells connected in series, and can also increase the battery capacity (Ah) by increasing the number connected in parallel.

[0003] As a battery pack for this purpose, a battery pack has been developed in which multiple cylindrical batteries are arranged in fixed positions using battery holders and housed in an exterior case (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-216366 Summary of the Invention [Problem to be solved by the invention]

[0005] FIG. 17 shows an exploded perspective view of the battery pack disclosed in Patent Document 1. This battery pack includes a core block 90 formed by arranging multiple battery cells in fixed positions in a battery holder 92. The core block 90 is then inserted into an outer case 93. The outer case 93 houses the core block 90 inside a cylindrical case body 94, with both end plates 95 closing both ends of the body. The case body 94 is shaped like a rectangular tube with both ends open. As shown in the enlarged cross-sectional view of FIG. 18, the inner surface of the case body 94 has multiple rows of ridges 94a extending longitudinally, which are integrally formed on the opposing surfaces to secure and close the end plates 95. These ridges 94a have longitudinal grooves 94b in their centers. At both ends of the ridges 94a, the open ends of the longitudinal grooves 94b serve as screw holes 94c into which set screws 96 are threaded, passing through the end plates 95. The end plates 95 are then secured to both ends of the case body 94.

[0006] In the battery packs described above, the case body and end plates are fixed via set screws, but the core block housed in the outer case is not fixed to the outer case. This means that when the battery pack is vibrated, the internal core block moves relative to the outer case, resulting in a structure that is unfavorable to vibration. The battery pack shown in FIG. 17 also has a structure in which a ring-shaped gasket 97 is sandwiched between the case body 94 and the end plate 95 to make the outer case 93 waterproof. This structure of the outer case 93 requires the set screws 96 to be tightened with a high torque to crush the gasket 97 and achieve a watertight structure. However, tightening the set screws with a high torque can locally twist the ridges 94a of the case body 94, potentially damaging the ridges 94a and the case body 94, as shown in the enlarged cross-sectional view of FIG. 18 . This requires the case body to be thick, which makes it impossible to make the case body thinner, resulting in a larger overall size and higher manufacturing costs. Furthermore, the screws must be added to the case body as a post-processing step, which increases manufacturing costs.

[0007] The present invention has been made in consideration of the above-described conventional background, and one of its purposes is to provide a battery pack in which the outer case for housing the core block is composed of a cylindrical main body portion and closing portions that close both end openings of the main body portion, while effectively preventing the core block housed inside from moving relative to the outer case, and in which the main body portion is formed thin to be lightweight and low cost, and in which the openings at both ends of the main body portion can be properly closed by the closing portions. [Means for solving the problem]

[0008] A battery pack according to one aspect of the present invention includes a core block formed by stacking and connecting multiple battery blocks, each of which has multiple battery cells arranged in fixed positions in a battery holder, an outer case having a cylindrical main body portion into which the core block is inserted and a pair of closing portions that close both end openings of the main body portion, and fastening members that fasten the pair of closing portions to sandwich the main body portion from both sides between the pair of closing portions. The core block is housed in the outer case with the multiple battery blocks stacked in the axial direction of the main body portion, and the fastening members fasten the pair of closing portions via the core block. [Effects of the Invention]

[0009] The above-described battery pack has the advantage of being able to accurately close both end openings of the tubular main body with closure parts while reducing manufacturing costs by simplifying the structure of the tubular main body. This is because the battery pack closes both ends of the tubular main body with closure parts by fastening a pair of closure parts with fastening members via a core block housed in the tubular main body. This battery pack does not require ridges for screw fastening on the inner surface of the tubular main body, allowing the tubular main body to be thin and lightweight, enabling inexpensive mass production. It also eliminates the risk of closure part fastening failure due to breakage of the ridges, allowing both end openings of the tubular main body to be stably closed with closure parts for a long period of time. Furthermore, because the above-described battery pack closes both ends of the tubular main body with a pair of closure parts fastened with fastening members via the core block, the core block housed inside and the outer case are integrally connected, effectively preventing the core block from moving relative to the outer case. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a battery pack according to a first embodiment of the present invention. [Figure 2] 1 is a perspective view of a battery pack according to a first embodiment of the present invention. [Figure 3] FIG. 2 is an exploded perspective view of the battery pack shown in FIG. [Figure 4] 4 is a vertical cross-sectional view of the battery pack shown in FIG. 1, and corresponds to the cross section taken along line IV-IV in FIG. 6. [Figure 5] 7 is a vertical cross-sectional view of the battery pack shown in FIG. 1, and corresponds to the cross section taken along line VV in FIG. 6. [Figure 6] 6 is a partially enlarged cross-sectional view of the battery pack shown in FIG. 4 taken along the line VI-VI. [Figure 7] 7 is a cross-sectional view of the battery pack shown in FIG. 4 taken along line VII-VII. [Figure 8] FIG. 2 is a perspective view of a core block made up of multiple battery blocks. [Figure 9] FIG. 2 is an exploded perspective view of the battery block. [Figure 10] FIG. 10 is an exploded perspective view of the electric block shown in FIG. 9 as seen from the rear. [Figure 11] FIG. 10 is an enlarged cross-sectional view showing another example of a fixing tool. [Figure 12] FIG. 10 is a schematic configuration diagram of a battery pack according to a second embodiment of the present invention. [Figure 13] FIG. 10 is a schematic configuration diagram of a battery pack according to a third embodiment of the present invention. [Figure 14] FIG. 10 is a schematic configuration diagram of a battery pack according to a fourth embodiment of the present invention. [Figure 15] FIG. 10 is a schematic cross-sectional view of a battery pack according to a fifth embodiment of the present invention. [Figure 16A] FIG. 1 is a schematic cross-sectional view of a battery pack according to a reference example. [Figure 16B] FIG. 1 is a schematic cross-sectional view of a battery pack according to a reference example. [Figure 17] FIG. 1 is an exploded perspective view of a conventional battery pack. [Figure 18] 18 is an enlarged cross-sectional view of a main part of a case body of the battery pack shown in FIG. 17. DETAILED DESCRIPTION OF THE INVENTION

[0011] A battery pack according to one embodiment of the present invention includes a core block formed by stacking and connecting multiple battery blocks, each of which has multiple battery cells arranged in fixed positions in a battery holder, an outer case having a cylindrical main body portion into which the core block is inserted and a pair of closing portions that close both end openings of the main body portion, and fastening members that fasten the pair of closing portions to sandwich the main body portion from both sides between the pair of closing portions. The core block is housed in the outer case with the multiple battery blocks stacked in the axial direction of the main body portion, and the fastening members fasten the pair of closing portions via the core block.

[0012] In this specification, "fastening" means a state in which the two parts are tightly clamped together and connected, and in a broad sense includes "clamping." Therefore, in this specification, "fastening from both sides" does not necessarily mean that the middle part is fixed, and is used to mean a state in which the two parts are simply passed through.

[0013] In another embodiment of the battery pack of the present invention, the fastening member includes a connector that connects all of the battery blocks of the core block and a fastener that fixes the blocking portion to the core block, and fastens a pair of blocking portions via the fastener that is fixed to the core blocks connected by the connector.

[0014] With this battery pack, all of the battery blocks in the core block are fastened with connectors, and a pair of closures are fastened via fasteners fixed to the core block. This allows multiple battery blocks to be integrally connected with connectors, while the pair of closures are fastened with fasteners, ensuring that both end openings of the tubular main body are properly closed with the closures. In particular, because this battery pack fastens all of the stacked battery blocks with connectors to form the core block, handling of the core block is easier during processes such as storing the core block in an exterior case, improving assembly efficiency.

[0015] In a battery pack according to another embodiment of the present invention, a connector connects one of the closing portions to the battery block of the core block.

[0016] According to the above battery pack, one of the blocking sections and all of the battery blocks of the core block are fastened together with a connecting device, and the other blocking section is fixed to the core block with a fixing device to fasten the pair of blocking sections. This reduces the number of fastening components, while allowing multiple battery blocks to be connected together with the connecting device and ensuring that the openings at both ends of the main body cylindrical section are properly blocked by the blocking sections.

[0017] In a battery pack according to another embodiment of the present invention, the fastening members are connectors that connect all of the battery blocks of the core block to the pair of closing portions.

[0018] According to the battery pack described above, a pair of closing sections are connected and fastened via a connector that connects all of the battery cells in the core block, thereby minimizing the number of fastening parts and reducing the number of manufacturing steps, thereby reducing manufacturing costs.

[0019] In another embodiment of the battery pack of the present invention, the fastening member includes a fastener that fixes a pair of closing portions to a specific battery block of the core block, and fastens the pair of closing portions via the fastener that is fixed to the specific battery block.

[0020] According to the above battery pack, a pair of blocking sections are fastened via fasteners that secure the blocking sections to specific battery blocks among the multiple battery blocks that make up the core block. This eliminates the need for connectors or the like with a total length sufficient to fasten all of the battery blocks, and allows the pair of blocking sections to be fastened using fasteners that are shorter than the total length of the core block.

[0021] In another embodiment of the battery pack of the present invention, the battery holder is integrally formed with a plurality of insertion cylindrical portions into which battery cells are inserted and held in place, and connecting protrusions that protrude outward from the insertion cylindrical portions and connect fastening members, and the connecting protrusions are provided with connecting portions to which fixing devices are connected.

[0022] In a battery pack according to another embodiment of the present invention, the fastener is a fastening screw. By using the fastener as a fastening screw, the battery pack can firmly fasten the closing portion while reducing manufacturing costs with a simple structure.

[0023] In another embodiment of the battery pack of the present invention, the battery holder is integrally formed with a plurality of insertion tube portions into which battery cells are inserted and held in place, and connecting protrusions that protrude outward from the insertion tube portions and connect fastening members, and the connecting protrusions are provided with insertion portions through which connecting devices are inserted.

[0024] In another embodiment of the battery pack of the present invention, the battery holder has a plurality of insertion cylindrical portions into which battery cells are inserted and held in place, and through holes are provided adjacent to and parallel to the insertion cylindrical portions, and fastening members are inserted into the through holes.

[0025] In the battery pack described above, through holes are provided adjacent to the insertion tubes of the battery holder, and fastening members are inserted through these through holes. When a battery cell generates heat, the heat radiated from the battery cell can be efficiently absorbed by the fastening members placed in the through holes. In particular, because the fastening members inserted through the through holes are positioned so as to penetrate the battery holder, the heat inside the battery holder containing the heated battery cell can be efficiently dissipated by being transferred to the outside of the battery holder via the fastening members.

[0026] In another embodiment of the battery pack of the present invention, the battery holder has multiple insertion tube portions that store multiple battery cells in multiple rows and columns, and fastening members are positioned adjacent to the battery cells arranged on the outer periphery of the battery holder.

[0027] With the above structure, in the event that a battery cell located on the periphery of the battery holder experiences an abnormal temperature and ignites or generates heat, the heat emitted from the ignited or heated battery cell is transferred to the fastening members, thereby reducing the heat transferred to battery cells adjacent to the ignited or heated battery cell and preventing ignition or heat generation in the adjacent battery cells. In particular, battery cells located on the periphery of the battery holder have fewer adjacent battery cells, making them more susceptible to temperature increases. However, a structure in which fastening members are located adjacent to battery cells located on the periphery of the battery holder reduces the heat transferred to battery cells adjacent to the ignited battery cell in the event that a battery cell ignites or generates heat, thereby preventing ignition or heat generation in the adjacent battery cells, effectively preventing major thermal damage that could spread to the entire battery pack, connected devices, and surrounding areas.

[0028] In another embodiment of the battery pack of the present invention, the closing portion is formed along the opening edge of the main body tubular portion and is provided with a stepped protrusion that is inserted into the main body tubular portion, and when the stepped protrusion is inserted inside the opening edge of the main body tubular portion, the outer peripheral edge of the closing portion abuts against the opening end surface of the main body tubular portion to close both end openings of the main body tubular portion.

[0029] The above battery pack has a stepped protrusion on the closing portion, which allows the closing portion to be connected to the main body tubular portion while being positioned, and the outer edge of the closing portion fastened with the fastening member can be abutted against the open end face of the main body tubular portion to ensure accurate closure.

[0030] In another embodiment of the battery pack of the present invention, the stepped protrusion has a ring groove on its outer surface and a ring-shaped gasket is placed in the ring groove, connecting the main cylindrical portion and the closing portion in a sealed structure via the gasket.

[0031] In the battery pack described above, the closure and the tubular main body can be connected in a sealed structure via a ring-shaped gasket attached to the outer peripheral surface of the stepped protrusion. In particular, this structure does not achieve a watertight connection by pressing the gasket in the direction of fastening the closure, but rather by interposing the gasket between the outer peripheral surface of the stepped protrusion and the inner peripheral surface of the tubular main body. This closes the gap between the stepped protrusion and the tubular main body by squeezing the gasket in a direction intersecting the fastening direction of the closure, thereby reliably sealing the stepped protrusion and the tubular main body. This allows the waterproof structure to be maintained over a long period of time without the need to tighten the closure to maintain its waterproof structure.

[0032] In another embodiment of the battery pack of the present invention, the main body cylindrical portion is cylindrical with a square cross section, the four corners are curved surfaces, and the outer peripheral shape of the stepped protrusion portion is shaped to follow the inner peripheral surface of the main body cylindrical portion.

[0033] The battery pack has a rectangular cylindrical body with curved corners, achieving a beautiful appearance and a soft feel. Furthermore, by shaping the outer periphery of the stepped protrusions to fit the inner periphery of the cylindrical body, the ring-shaped gasket can be comfortably positioned on the curved corners of the rectangular cross section, effectively preventing localized deformation of the gasket.

[0034] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to these. Furthermore, this specification in no way specifies the components set forth in the claims as components of the embodiments. The dimensions, materials, shapes, and relative positions of components described in the embodiments are not intended to limit the scope of the present invention, and are merely illustrative unless otherwise specified. The size and relative positions of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present invention may be configured with the same components, so that one component serves multiple functions, or conversely, the function of one component may be shared by multiple components. Furthermore, the content described in some examples and embodiments may be applicable to other examples and embodiments.

[0035] The battery pack of the present invention is primarily mounted on an electric vehicle to supply power to the drive motor. It can be used, for example, as a power source for power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the present invention does not specify the use of the battery pack, and it can also be used as a power source for various electrical devices used indoors and outdoors, such as cleaners and power tools.

[0036] (Embodiment 1) A battery pack according to a first embodiment of the present invention is shown in Figures 1 to 10. Figure 1 shows a schematic configuration diagram of the battery pack, Figure 2 shows a perspective view of the battery pack, Figure 3 shows an exploded perspective view of the battery pack, Figures 4 and 5 show vertical cross-sectional views of the battery pack, Figure 6 shows a partially enlarged cross-sectional view taken along line VI-VI of Figure 4, Figure 7 shows a cross-sectional view taken along line VII-VII of Figure 4, Figure 8 shows a perspective view of the core block, Figure 9 shows an exploded perspective view of the battery block, and Figure 10 shows an exploded perspective view of the battery block as seen from the rear side. In this specification, the horizontal and vertical directions are defined as the directions shown in Fig. 4. That is, the left-right direction on the paper surface of Fig. 4 is defined as the horizontal direction. Also, the longitudinal direction of the battery cell is defined as the length direction.

[0037] The battery pack 100 shown in these figures includes a core block 10 formed by stacking and connecting multiple battery blocks 9, each of which has multiple battery cells 1 arranged in fixed positions in a battery holder 2, an outer case 3 having a cylindrical main body portion 4 into which the core block 10 is inserted, and a pair of closing portions 5 that close the openings at both ends of the main body portion 4, and fastening members 6 that fasten the pair of closing portions 5 together to sandwich the main body portion 4 from both sides. The core block 10 is housed in the outer case 3 with multiple battery blocks 9 stacked in the axial direction of the main body portion 4, and the fastening members 6 fasten the pair of closing portions 5 together via the core block 10.

[0038] (Core Block 10) As shown in Figures 8 to 10, the core block 10 is made up of multiple battery blocks 9, each of which has multiple battery cells 1 arranged in multiple rows and columns in a battery holder 2. These battery blocks 9 are stacked in the longitudinal direction of the battery cells 1 and connected linearly. The core block 10 shown in Figures 6 to 8 has four battery blocks 9. In this core block 10, multiple battery cells 1 are connected in parallel to increase battery capacity (Ah), and multiple battery cells 1 are connected in series to increase output voltage (V). The core block 10 shown in the figures has four battery blocks 9, but the battery pack of the present invention can have a core block made up of three or fewer battery blocks 9, or five or more battery blocks 9.

[0039] (Battery block 9) 9 and 10, each battery block 9 has a battery holder 2 provided with a cylindrical insertion section 21 for the battery cells 1, and the battery cells 1 are inserted into the cylindrical insertion section 21 to arrange the battery cells 1 in fixed positions. As shown in the exploded perspective views of FIGS. 9 and 10, the battery block 9 arranges multiple rechargeable battery cells 1 in multiple rows and columns in the battery holder 2.

[0040] The battery cell 1 is a cylindrical rechargeable secondary battery, specifically a lithium-ion secondary battery. However, the present invention does not limit the battery cell to lithium-ion batteries, and any other rechargeable secondary battery, such as a nickel-water battery cell, a nickel-cadmium battery, or a lithium polymer battery, can be used.

[0041] A battery block 9 has multiple battery cells 1 arranged in parallel with the longitudinal direction of each battery cell 1 facing in the same direction. The multiple battery cells 1 that make up the battery block 9 are connected to the desired number of parallel and series connections using lead plates (not shown) connected to the end surface electrodes on both ends of the battery cells 1, or are connected on a circuit board 8 shown by the chain line in Figure 7. The core block 10 shown in Figure 8 connects four battery blocks 9, each with 10 battery cells, for a total of 40 battery cells connected in 4 parallel and 10 series configurations. However, the number and connection configuration of the battery cells 1 in the core block 10 can be freely changed.

[0042] (Battery holder 2) As shown in Figures 9 and 10, the battery holder 2 is made by molding insulating plastic into the same shape, and the insertion tube portion 21 for the battery cell 1 and the connecting protrusion portion 22 to which the fastening member 6 is connected are molded integrally.

[0043] The insertion tube portion 21 holds the battery cells 1 set therein in a fixed position. The battery holder 2 shown in the figure has cylindrical battery cells 1, and the insertion tube portion 21 is shaped to insert and hold cylindrical batteries in a fixed position. However, the present invention does not necessarily limit the battery cells to cylindrical batteries; the battery cells can also be, for example, prismatic batteries. In a battery pack using prismatic battery cells, the insertion tube portion of the battery holder is prismatic.

[0044] The battery holder 2 in the figure has 10 battery cells 1 arranged in three vertical rows, with the batteries arranged in three rows, four rows, and three rows from top to bottom, in a rice bale-like configuration, with the upper and lower battery cells 1 positioned in the gaps between adjacent battery cells 1 on the left and right.

[0045] As shown in Figures 9 and 10, the battery holder 2 is formed into a pair of cell holders 2a and 2b. Each of the cell holders 2a and 2b that make up the battery holder 2 has an insertion tube portion 21 into which a battery cell 1 is inserted in a parallel position. The insertion tube portion 21 is open at both ends, exposing the end electrodes of the cylindrical battery inserted therein so that lead plates can be connected to the end electrodes. The insertion tube portions 21 of the cell holders 2a and 2b are long enough to insert half of a battery cell 1, and each battery cell 1 is placed in its designated position in the battery holder 2 by inserting half into one cell holder 2a and the other half into the other cell holder 2b.

[0046] The pair of cell holders 2a, 2b have mating sections consisting of mating projections 25 and mating recesses 26 on their opposing surfaces, allowing them to be connected to each other in a fixed position. The cell holder 2b shown in Figure 9 has mating projections 25 located on the left and right sides of its upper end, while the cell holder 2a shown in Figure 10 has mating mating recesses 26 located on the left and right sides of its upper end. The pair of cell holders 2a, 2b are connected by mating the mating projections 25 and mating recesses 26 to prevent misalignment of their relative positions. The pair of cell holders 2a, 2b are connected in a fixed position via the battery cells 1, as the battery cells 1 are inserted into the opposing insertion tube portions 21 of the cell holders 2a, 2b. The battery holder 2 with the above structure 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 21 of the two divided cell holders 2a, 2b. However, the battery holder does not necessarily have to be configured as two divided cell holders, but can also be configured as a single holder or as three or more divided cell holders.

[0047] The battery holder 2 has connecting protrusions 22 on the cell holders 2a and 2b that protrude outward from the insertion tube portion 21. The connecting protrusions 22 of the battery holder 2 are molded integrally with the plastic cell holders 2a and 2b. The cell holders 2a and 2b shown in Figures 9 and 10 have connecting protrusions 22 at the four corners when viewed from the front. The connecting protrusions 22, which will be described in detail later, include a connecting portion 23 to which the fixing device 14 constituting the fastening member 6 is connected, and an insertion portion 24 through which the connector 11 is inserted. In the battery holder 2 shown in the figures, the connecting protrusions 22 formed on both sides of the upper part are composed of an insertion portion 24 and a connecting portion 23, and the connecting protrusions 22 formed on both sides of the lower part are composed of a connecting portion 23.

[0048] Furthermore, the battery holder 2 shown in the figures is also provided with mating protrusions 27 and mating recesses 28 for connecting stacked battery blocks 9 together in a fixed position. The battery holders shown in Figures 9 and 10 have mating portions consisting of mating protrusions 27 and mating recesses 28 on the opposing surfaces of adjacent battery blocks 9, enabling them to be connected to each other in a fixed position. The cell holder 2b shown in Figure 10 has connecting protrusions 22 on the left and right sides of the upper part and mating protrusions 27 located on the left and right sides of the lower end, while the cell holder 2a shown in Figure 9 has connecting protrusions 22 on the left and right sides of the upper part and mating recesses 28 located on the left and right sides of the lower end, facing each other. Adjacent battery blocks 9 are connected by mating the mating protrusions 27 with the mating recesses 28 to prevent misalignment of their relative positions.

[0049] (Circuit board 8) Furthermore, the core block 10 is equipped with a circuit board 8 connected to the battery blocks 9. The core block 10 shown in FIG. 8 has the circuit board 8 placed on the top surface of the battery blocks 9, which are connected in a straight line. The circuit board 8 is placed in a fixed position, for example, via a board holder (not shown). Although not shown, the lead plates connected to the multiple battery cells 1 are connected to the circuit board 8 directly or via connection lines. The circuit board 8 is equipped with electronic components that implement a protection circuit that controls the charging and discharging of the battery cells 1. The protection circuit also includes a circuit that detects the voltage of each battery and cuts off the charging and discharging current. The circuit board is also equipped with a temperature detection circuit that detects abnormal temperatures in the battery cells 1.

[0050] (Outer case 3) As shown in Figures 2 to 7, the outer case 3 comprises a main body tubular portion 4 formed in a cylindrical shape with openings at both ends, and a pair of closing portions 5 that close the openings at both ends of the main body tubular portion 4. With a core block 10 inserted into the main body tubular portion 4, the pair of closing portions 5 are fastened with fastening members 6, and both ends of the main body tubular portion 4 are clamped and closed by the pair of closing portions 5 from both sides.

[0051] The cylindrical main body 4 is made of a metal with excellent strength and heat dissipation, such as aluminum or an aluminum alloy. The cylindrical main body 4 is formed by processing aluminum and can be formed into a cylindrical shape by extrusion or pultrusion. The surface of the metallic cylindrical main body 4 can be insulated by covering it with a laminate film or vinyl. However, the cylindrical main body 4 can also be made of a metal of another element, such as a magnesium alloy, or a fiber-reinforced resin made by impregnating reinforcing fibers, such as carbon fiber, silica fiber, or glass fiber, with a thermosetting resin, such as epoxy resin, and then hardening the impregnated material. The blocking portion 5 is made of a hard plastic. However, the blocking portion 5 can also be made of a metal or a fiber-reinforced resin.

[0052] The tubular main body 4 has a generally rectangular cross section and is molded into a generally rectangular tube shape with both ends open. Furthermore, the four corners of the rectangular tubular main body 4 are chamfered to form curved surfaces 4a. Because the corners of the tubular main body 4 are curved surfaces 4a, the exterior case 3 has a rectangular tube shape, resulting in a beautiful appearance and a soft feel.

[0053] The closure portion 5 has an outer peripheral edge 52 formed in a cross-sectional view that conforms to the outer shape of the tubular main body 4 so as to provide a good appearance when closing the open end of the tubular main body 4. Furthermore, the closure portion 5 includes a stepped protrusion 51 formed along the edge of the open end of the tubular main body 4 and inserted into the tubular main body 4. When the stepped protrusion 51 is inserted inside the open end of the tubular main body 4, the outer peripheral edge 52 of the closure portion 5 abuts against the open end surface of the tubular main body 4, thereby closing both end openings of the tubular main body 4. That is, the outer shape of the stepped protrusion 51 of the closure portion 5 is slightly smaller than the inner shape of the tubular main body 4, and the outer shape of the outer peripheral edge 52 is approximately equal to or slightly larger than the outer shape of the tubular main body 4. The closure portion 5 closes both end openings of the tubular main body 4 by abutting the abutment surface 54 of the outer peripheral edge 52 formed outside the stepped protrusion 51 against the open end surface of the tubular main body 4. The outer case 3 has a stepped protrusion 51 on the closing portion 5, which allows the closing portion 5 to be connected to the main body tubular portion 4 while being positioned, and the outer peripheral edge 52 of the closing portion 5, which is fastened with the fastening member 6, can be abutted against the open end face of the main body tubular portion 4 to ensure accurate closure.

[0054] Furthermore, the closure 5 shown in the figure has a ring groove 53 on the outer peripheral surface of the stepped protrusion 51, and a ring-shaped gasket 7 is placed in this ring groove 53. This exterior case 3 connects the tubular main body 4 and the closure 5 in a sealed structure via the ring-shaped gasket 7 placed on the outer peripheral surface of the stepped protrusion 51. In particular, this sealed structure does not achieve a watertight connection by pressing the gasket in the fastening direction of the closure 5, but rather by interposing the gasket 7 between the outer peripheral surface of the stepped protrusion 51 and the inner peripheral surface of the tubular main body 4, thereby crushing the gasket 7 in a direction intersecting the fastening direction of the closure 5, thereby sealing the stepped protrusion 51 and the tubular main body 4 in a watertight manner. Therefore, even if the fastening member 6 loosens and the tubular main body 4 and the closure 5 move slightly relative to each other, the amount of crushing of the gasket 7 does not change, and the compressive force of the gasket 7, i.e., the sealing pressure, does not change, resulting in a stable and reliable seal. Therefore, the waterproof structure of the closure 5 can be reliably maintained for a long period of time without the need to tighten the closure 5 to maintain its waterproof structure. Furthermore, the outer peripheral shape of the stepped protrusion 51 of the closing portion 5 is shaped to fit the inner peripheral surface of the tubular main body portion 4. As the tubular main body portion 4 has a quadrangular shape in cross section with curved surfaces 4a at its four corners, the outer peripheral shape of the stepped protrusion 51 is also shaped to fit this quadrangular shape, with its four corners curved. This allows the ring-shaped packing 7 set on the outer peripheral surface of the stepped protrusion 51 to be comfortably positioned, effectively preventing the packing 7 from being locally deformed.

[0055] Furthermore, although not shown, the closing section 5 can be provided with a discharge connector for discharging the built-in battery cells 1 and a charge connector for charging the built-in battery cells 1. Furthermore, the closing section 5 can also be provided with a display section on its surface that displays the remaining capacity of the battery pack 100. This display section displays the remaining capacity of the battery pack, for example, by lighting a light source such as an LED.

[0056] Furthermore, the closing portion 5 has a boss portion 55 on the inside of the stepped protrusion 51 for inserting a fastening member. As shown in Figures 3 and 7, this boss portion 55 is located opposite the connecting portion 23 on the battery holder 2. The boss portion 55 is formed inside the stepped protrusion 51 in a position that protrudes in the longitudinal direction. As shown in Figure 7, the closing portion 5 has an insertion recess 56 located on the rear end side of the boss portion 55 for inserting the fastening member 6, and the boss portion 55 has a through-hole for passing the fastening member 6 therethrough.

[0057] (Fastening member 6) The fastening members 6 fasten the pair of closing sections 5 together, sandwiching the main body tubular section 4 from both sides between the pair of closing sections 5. The fastening members 6 fasten the pair of closing sections 5 via the core block 10 housed in the outer case 3. The fastening members 6 shown in Figures 1 and 3 to 7 include connectors 11 that connect the battery blocks 9 of the core block 10, and fixtures 14 that secure the closing sections 5 to the core block 10.

[0058] Here, the fastening members 6 refer to members for clamping the tubular main body portion 4 from both sides by fixing the pair of closing portions 5 to the core block 10. In cases where the core block 10 is composed of multiple separable battery blocks 9, the fastening members 6 also include members for integrally connecting these battery blocks 9. Therefore, an example of the fastening members 6 can be configured with a connector 11 for connecting the multiple battery blocks 9 and a fixture 14 for fixing the closing portions 5 to the core block 10. However, in cases where the multiple battery blocks 9 that make up the core block 10 are integrally fixed via the battery holder 2, members for connecting the multiple battery blocks 9 are not necessarily required. Therefore, in such cases, the connectors can be omitted. However, even in such cases, the connection strength can be increased by connecting the multiple battery blocks with connectors.

[0059] (Connector 11) The connector 11 linearly connects the multiple battery blocks 9 that make up the core block 10. The connector 11 shown in the figure includes a connecting screw 12 that passes through the insertion portion 24 on the connecting protrusion 22 of the battery holder 2, and a nut member 13 into which the tip of the connecting screw 12 screws. The connecting screw 12 shown in the figure has a screw head at the rear end and a male thread at the tip, and is long enough to connect four battery blocks 9. The connector 11 is preferably made of metal and is strong enough to fasten and connect multiple battery blocks 9 from both sides. Metal connectors 11 have a large thermal capacity and are capable of effectively absorbing and transferring heat even when the battery cells 1 generate heat. The connector 11 described above integrally connects multiple battery blocks 9 arranged in a linear arrangement by inserting the connecting screw 12 into the insertion portion 24 on the battery holder 2 of each battery block 9 and connecting the nut member 13 to the tip of the connecting screw 12. The above connector 11 is comprised of a connecting screw 12 that passes through multiple battery blocks 9 and a nut member 13 into which the connecting screw 12 is screwed, but the connecting screw can also be fixed by directly screwing it into a boss hole or the like provided on the battery holder. Furthermore, the connector is not necessarily limited to the above structure, and can be any other structure that can connect multiple battery blocks 9, such as a threaded rod and nut.

[0060] The core block 10 shown in Figures 4 to 7 has connectors 11 inserted into the insertion sections 24 of the connecting protrusions 22 of the battery holder 2 and positioned outside the battery holder 2. The battery holder 2 shown in Figures 4 and 5 has multiple insertion tube sections 21 that store multiple battery cells 1 in multiple rows and columns, and connectors 11, which are fastening members 6, are positioned adjacent to the battery cells 1 positioned on the outer periphery of the battery holder 2. The battery holder 2 shown in Figures 4 and 5 has multiple battery cells 1 arranged in three rows and columns, with connectors 11 positioned outside the battery cells 1 positioned at both ends of the upper row and the middle row—in other words, at the corners of the battery holder 2, which has a roughly rectangular cross section. In the unlikely event that a battery cell 1 positioned on the outer periphery catches fire or generates heat due to an internal short circuit or other reason, the connectors 11 positioned in this position can efficiently dissipate heat released from the ignited battery cell. In particular, the connectors 11 have a large heat capacity due to their long overall length in order to connect multiple battery cells 1, allowing them to efficiently dissipate heat released from a ignited battery cell 1. The core block 10 shown in the figure has two connectors 11 positioned at the corners of the battery holder 2, but the core block can also accommodate three or more connectors. Additionally, the fastening members can be inserted through through holes provided in the battery holder, as will be described in more detail below.

[0061] (fixture 14) As shown in FIG. 7 , the fastener 14 penetrates the closure section 5 and connects its tip to the core block 10, thereby securing the closure section 5 to the core block 10. The fastener 14 is preferably made of metal and has sufficient strength to be securely fastened to the core block 10. Metal fasteners 14 have excellent heat conductivity and are characterized by their ability to effectively transfer heat from the core block 10 to the closure section. The fastener 14 shown in the figure is a fixing screw 14A. The battery pack 100 shown in the figure has four corners of the closure section 5 fixed to the core block 10 via the fixing screws 14A. As shown in FIG. 7 , the fixing screw 14A can be inserted into the insertion recess 56 of the closure section 5, penetrates the boss 55, and is then screwed into the battery holder 2, allowing for simple and reliable fastening. The fixing screw 14A shown in FIG. 7 is screwed into a connecting boss, which is a connecting portion 23 provided on the battery holder 2 of the battery block 9 located closest to the core block 10, to secure the core block 10. The fixing screw 14A shown in the figure is designed to be directly screwed into the connecting portion 23 on the battery holder 2, but the fixing screw can also be screwed into a nut member that is previously fixed to the battery holder 2 by embedding it in place. This fixing structure allows the fixing screw 14A to be more firmly fixed to the core block 10.

[0062] Furthermore, the fastener 14 is not limited to the fixing screw 14A; any other component capable of connecting the closure 5 to the core block 10 can be used. The fastener 14 can also be a rivet 14R, as shown in FIG. 11. Such a rivet 14R can be, for example, a blind rivet. FIG. 11 shows the rivet 14R connecting the boss 55B of the closure 5B to the connecting portion 23B of the front-most battery holder 2B. The blind rivet 14R passes its tip through the boss 55B and the connecting portion 23B, and then crimps the tip. This connects the boss 55B and the connecting portion 23B from both sides between the flange 14s at the rear end and the crimped portion 14t at the tip. This structure has the advantage of connecting the closure 5B and the battery holder 2B in the shortest distance. However, the rivet can also be made longer to connect the closure to multiple battery holders.

[0063] The above fastening member 6 connects multiple battery blocks 9 with connectors 11 to form a core block 10, inserts this core block 10 into the main body tubular portion 4, and then connects and fixes a fixing device 14 that passes through the blocking portion 5 to the connecting portion 23 of the battery holder 2 located at the frontmost side of the core block 10, and clamps the main body tubular portion 4 from both sides with a pair of blocking portions 5 fixed to both ends of the core block 10, thereby blocking the openings at both ends of the main body tubular portion 4 with the blocking portions 5.

[0064] As described above, the battery pack according to the first embodiment integrally connects multiple battery blocks 9 that make up the core block 10 via connectors 11, and fastens a pair of closing sections 5 by connecting and fixing fasteners 14 inserted through the closing sections 5 to both ends of the integrally connected core block 10. However, the battery pack can also fasten a pair of closing sections using the following structure shown in Figures 12 to 14.

[0065] (Embodiment 2) 12 shows an example of a battery pack 200 in which a fixing screw 14B inserted into one of the closing sections 5 (on the left side in the figure) also serves as a connecting screw 12B that connects multiple battery blocks 9. In the battery pack 200 shown in this figure, the fixing screws 14B inserted into the closing section 5 are inserted into all of the battery blocks 9, and nuts 13 are connected to the tips of the fixing screws 14B, integrally connecting the one of the closing sections 5 and the multiple battery blocks 9 with connecting devices 11B consisting of connecting screws 12B (fixing screws 14B) and nuts 13. In a battery pack 200 with this structure, the one of the closing sections 5 and all of the battery blocks 9 are connected to each other by fixing screws 14B (connecting screws 12B) that are also connecting screws 14B to form a core block 10. Therefore, even if one of the battery cells 1 in the core block 10 ignites or generates heat, the heat released from that battery cell 1 can be transferred to the closing section 5 via the fixing screw 14B, effectively dissipating the heat to the outside of the exterior case 3.

[0066] The above-mentioned fastening member 6B is used to integrally connect one of the blocking portions 5 (left side in the figure) and multiple battery blocks 9 with a connecting device 11B, and then the core block 10 is inserted into the main body tubular portion 4, one opening (left side in the figure) of the main body tubular portion 4 is blocked by the blocking portion 5, and at the opposite opening (right side in the figure), a fixing screw 14A that passes through the other blocking portion 5 (right side in the figure) is screwed into the connecting portion 23 of the battery holder 2 located at the front side of the core block 10 to fix it, and the pair of blocking portions 5 fixed to both ends of the core block 10 clamp the main body tubular portion 4 from both sides, blocking both end openings of the main body tubular portion 4 with the blocking portions 5.

[0067] (Embodiment 3) 13 shows an example of a battery pack 300 in which connectors 11C connecting multiple battery blocks 9 also serve as fixing screws 14C connecting a pair of closing sections 5 to the core block 10. The battery pack 300 shown in this figure uses connecting screws 12C connecting the battery blocks 9 as fixing screws 14C inserted into the closing sections 5. These connecting screws 12C are inserted through the closing sections 5 and all of the battery blocks 9, and also pass through the other closing section 5 at its tip to connect a nut member 13 to the tip, integrally connecting all of the battery blocks 9 in the core block 10 to the pair of closing sections 5 with the connectors 11C. In a battery pack 300 with this structure, the pair of closing sections 5 and all of the battery blocks 9 are connected by fixing screws 14C, which are also connecting screws 12C. Therefore, even if one of the battery cells 1 in the core block 10 ignites or generates heat, the heat released from that battery cell 1 can be transferred via the fixing screws 14C to the closing sections 5 on both sides, enabling more effective heat dissipation to the outside of the exterior case 3.

[0068] The above-mentioned fastening member 6C is used by inserting the core block 10 into the main body tubular portion 4 with the connecting device 11C inserted through one of the blocking portions 5 (right side in the figure) and multiple battery blocks 9, blocking one opening (right side in the figure) of the main body tubular portion 4 with the blocking portion 5 and blocking the opening on the opposite side (left side in the figure) with the other blocking portion 5 (left side in the figure).A nut member 13 is connected to the tip of the connecting screw 12C that passes through this blocking portion 5, and the main body tubular portion 4 is clamped from both sides with the pair of blocking portions 5 fixed to both ends of the core block 10, thereby blocking both end openings of the main body tubular portion 4 with the blocking portions 5.

[0069] (Embodiment 4) A battery pack 400 shown in FIG. 14 uses fastening members 6D consisting of fixing screws 14D and 14E that fix a pair of closing portions 5 to specific battery blocks 9 of a core block 10. This battery pack 400 is configured so that when the fixing screws 14D and 14E inserted through the closing portions 5 are fixed to the core block 10, the multiple battery blocks 9 that make up the core block 10 are also connected and fixed. In the example shown in FIG. 14 , fixing screws 14D and 14E are inserted from both sides into a specific battery block 9 that is located in the middle of the multiple battery blocks 9 that make up the core block 10, and the pair of closing portions 5 are fixed to the core block 10 via the pair of fixing screws 14D and 14E fixed to this battery block 9. For the middle battery block 9 to which the fixing screws 14D and 14E are fixed, nuts 13 are placed in advance at the positions where the fixing screws 14D and 14E are screwed, so that the fixing screws 14D and 14E can be firmly fixed to the battery block 9. In a battery pack 400 with this structure, the closing section 5 and all of the battery blocks 9 are connected by fixing screws 14D, 14E. Therefore, even if one of the battery cells 1 in the core block 10 catches fire or generates heat, the heat released from this battery cell 1 can be transferred to the closing section 5 via one of the fixing screws 14D, 14E, and is effectively dissipated to the outside of the exterior case 3.

[0070] The fastening member 6D described above connects one closing portion 5 (left side in the figure) and a predetermined number (three in the figure) of battery blocks 9 with a fixing screw 14D and a nut member 13. The connected battery blocks 9 are then inserted into the tubular main body portion 4, and one opening (left side in the figure) of the tubular main body portion 4 is closed with the closing portion 5. A fixing screw 14E is then inserted into the other closing portion 5 (right side in the figure) and the predetermined number (one in the figure) of battery blocks 9, and the tip of the inserted fixing screw 14E is connected to the connected battery block 9 with the fixing screw 14D, fastening the pair of closing portions 5 together with the fixing screw 14D, 14E that secures the specific battery block 9 (third from the left in the figure). The core block 10 is also formed by connecting multiple battery blocks 9 together via the fixing screw 14D, 14E that connects the specific battery block 9. This battery pack 400 has blocking portions 5 arranged at both ends of the core block 10 fixed to the same battery block 9 located in the middle of the core block 10 via fixing screws 14D and 14E, respectively, so that the pair of blocking portions 5 clamp the main body tubular portion 4 from both sides, thereby blocking the openings at both ends of the main body tubular portion 4.

[0071] (Embodiment 5) Furthermore, the battery pack 500 shown in FIG. 15 illustrates an example in which connecting screws 12, which serve as fastening members 6, are disposed by passing through a battery holder 2C. This battery holder 2C includes multiple insertion tube portions 21 that accommodate multiple battery cells 1 in multiple rows and columns. Through-holes 29 are provided adjacent to and parallel to the insertion tube portions 21. The battery holder 2C in FIG. 15 has multiple battery cells 1 arranged in three rows, one above the other. The through-holes 29 are located outside the battery cells 1 at both ends of the upper row and the other at both ends of the middle row, and also outside the battery cells 1 at both ends of the lower row and the other at both ends of the middle row. That is, the battery holder 2C in the figure has a generally rectangular cross-section and four through-holes 29 located at the four corners. Each through-hole 29 is located adjacent to a battery cell 1 located on the outer periphery of the battery holder 2C. 15 is arranged such that connecting screws 12, which are fastening members 6, pass through each of the through-holes 29 of the battery holders 2C. A battery pack 500 with this structure has the advantage that the connecting screws 12 that pass through the battery holders 2C can prevent the chain reaction of fire outbreaks and the spread of fire, as described below.

[0072] 16, if any of the battery cells 1 placed in the battery holder 82 were to catch fire or generate heat due to an internal short circuit or other reason, the adjacent battery cell 1Y adjacent to the ignited battery cell 1X would receive the heat and its temperature would rise, and if the temperature rise was severe, the adjacent battery cell 1Y would also catch fire and generate heat. This would result in a chain reaction of fires and heat generation in other battery cells 1, causing a major thermal problem that could spread to the entire battery pack, connected devices, and surrounding areas.

[0073] The heat released from the ignited battery cell 1X is transferred radially to the surrounding area. Let Mi and ΔTi be the heat capacities and temperature rises of all components within the area affected by the released heat, respectively. Since the adjacent battery cell 1Y is included among all components, Q = Σ{M(i) × ΔT(i) + M(1Y) × ΔT(1Y)}. To reduce the temperature rise ΔT(1Y) of the adjacent battery cell 1Y, we need to either increase the heat capacity of the adjacent battery cell 1Y or place a component with as large a heat capacity as possible within the area affected by the released heat. The battery cell 1 is composed of a metal outer can and a group of electrodes, each consisting of long positive and negative electrodes with a long separator placed between them, tightly wound. The heat capacity of the battery cell 1 is therefore greater than that of other components, such as plastic components such as the battery holder 82.

[0074] 16A, if the battery cell 1 designated by A among the battery cells 1 arranged inside the battery holder 82 catches fire and generates heat, the heat released from this battery cell 1X that caught fire is transferred to the six adjacent battery cells 1Y arranged around it. In this case, because the battery cells are arranged radially symmetrically around the ignited battery cell 1X, the heat is transferred fairly evenly to the six adjacent battery cells 1Y, i.e., approximately 1 / 6 of the heat is transferred.

[0075] In contrast, in Figure 16B, if a battery cell 1 designated by B among the battery cells 1 arranged on the periphery of the battery holder 82 catches fire or generates heat, the heat released from this ignited battery cell 1X is transferred to the three adjacent battery cells 1Y arranged around it. In this case, the heat is transferred more evenly to the three adjacent battery cells 1Y, i.e., approximately one-third. Therefore, in the case of Figure 16B, the amount of heat transferred to the adjacent battery cell 1Y increases compared to the case of Figure 16A, making the temperature of the adjacent battery cell 1Y more likely to rise, and making the adjacent battery cells 1Y more likely to catch fire or generate heat in a chain reaction.

[0076] As a result, the degree of temperature rise of the adjacent battery cell 1Y depends on the position of the ignited battery cell 1X. When a battery cell 1 located on the outer periphery of the battery holder 2 ignites and generates heat, the degree of temperature rise of the battery cell 1 is greatest.

[0077] In contrast, as shown in Figure 15, if a structure is used in which metal connecting screws 12 serving as fastening members 6 are placed adjacent to the battery cells 1 (C) located on the outer periphery of the battery holder 2C, the heat released from the igniting battery cell 1X is transferred not only to the three surrounding adjacent battery cells 1Y but also to the connecting screws 12, thereby reducing the amount of heat transferred to the adjacent battery cells 1Y and suppressing the temperature rise of the adjacent battery cells 1Y, making it less likely that a chain reaction of fire and heat will occur. In particular, the connecting screws 12 used as fastening members 6 are inserted so as to penetrate multiple battery blocks 9, which means that they are long in overall length and have a large heat capacity, making them even more preferable as they are made of metal with good thermal conductivity. [Industrial Applicability]

[0078] The battery pack according to the present invention is attached to an electric vehicle and supplies power to a drive motor, and can be suitably used as a power source for, for example, an electric motor-assisted bicycle, an electric motorcycle, an electric wheelchair, an electric tricycle, an electric cart, etc. [Explanation of symbols]

[0079] 100, 200, 300, 400, 500... Battery packs 1...Battery cell 1x…ignited battery cell 1Y: Adjacent battery cells 2, 2B, 2C...Battery holder 2a...Cell holder 2b...Cell holder 3...Outer case 4...Main body cylinder 4a...Curved surface 5, 5B...Occluded part 6, 6B, 6C, 6D... Fastening members 7...Gasket 8...Circuit board 9...Battery block 10...Core block 11, 11B, 11C...Connector 12, 12B, 12C...Connecting screws 13...Nut member 14...Fixing tool 14A, 14B, 14C, 14D, 14E...Fixing screws 14R...Rivet 14s...Flange 14t...crimped part 21...insertion tube 22...Connecting protrusion 23, 23B…Connection part 24...Passage part 25...Fitting protrusion 26...Fitting recess 27...Fitting protrusion 28...Mating recess 29...Through hole 51...Step convex part 52...Outer edge 53...Ring groove 54…Contact surface 55, 55B...Boss part 56...Insertion recess 82...Battery holder 90...Core block 92...Battery holder 93...Outer case 94...Case body 94a...Convex strip 94b...Vertical groove 94c...screw hole 95...End plate 96...Set screw 97...Gasket

Claims

1. a core block formed by stacking and connecting a plurality of battery blocks, each of which has a plurality of battery cells arranged in fixed positions in a battery holder; an outer case including a cylindrical main body portion into which the core block is inserted and a pair of closing portions that close openings at both ends of the cylindrical main body portion; a fastening member for fastening the pair of closing portions together to sandwich the main body tubular portion between the pair of closing portions, the core block is housed in the exterior case in a position where a plurality of the battery blocks are stacked in the axial direction of the main body cylindrical portion, The fastening member fastens the pair of closing portions together via the core block.

2. 2. The battery pack according to claim 1, The fastening member is a connector that connects all of the battery blocks of the core block; a fastener for fastening the blocking portion to the core block, A battery pack is formed by fastening a pair of the closing portions via the fasteners fixed to the core blocks connected by the connectors.

3. 3. The battery pack according to claim 2, The battery pack is characterized in that the connector connects one of the closing portions and the battery block of the core block.

4. 2. The battery pack according to claim 1, The fastening member is a connector that connects all of the battery blocks of the core block to the pair of closing portions of the battery pack.

5. 2. The battery pack according to claim 1, the fastening member includes a fastener that fixes the pair of closing portions to the specific battery block of the core block; A battery pack is formed by fastening a pair of the closing portions together via the fastener that is fixed to a specific battery block.

6. 6. The battery pack according to claim 2, 3, or 5, The battery holder is a plurality of insertion tubes into which the battery cells are inserted and held in position; a connecting protrusion that protrudes outward from the insertion tube portion and connects the fastening member; are integrally molded, The battery pack is characterized in that the connecting protrusion is provided with a connecting portion to which the fixing device is connected.

7. 7. The battery pack according to claim 2, 3, 5, or 6, The battery pack, wherein the fastener is a fastening screw.

8. 5. The battery pack according to claim 2, wherein: The battery holder is a plurality of insertion tubes into which the battery cells are inserted and held in position; a connecting protrusion that protrudes outward from the insertion tube portion and connects the fastening member; are integrally molded, The battery pack according to claim 1, wherein the connecting protrusion is provided with an insertion portion through which the connecting tool is inserted.

9. 6. The battery pack according to claim 1, the battery holder includes a plurality of insertion tube portions into which the battery cells are inserted and held in fixed positions, and through holes are provided adjacent to and parallel to the insertion tube portions; The fastening member is inserted into the through hole.

10. 10. The battery pack according to claim 1, the battery holder includes a plurality of insertion tube portions that accommodate a plurality of the battery cells in multiple rows and columns, The fastening member is disposed adjacent to the battery cell disposed on the outer periphery of the battery holder.

11. 11. The battery pack according to claim 1, the closing portion is formed along an opening edge of the tubular main body portion and includes a stepped protrusion portion that is inserted into the tubular main body portion, A battery pack in which the stepped protrusion is inserted inside the opening edge of the main body cylindrical portion, and the outer peripheral edge of the closing portion abuts against the opening end surface of the main body cylindrical portion, thereby closing both end openings of the main body cylindrical portion.

12. 12. The battery pack according to claim 11, the step protrusion has a ring groove on its outer circumferential surface, and a ring-shaped packing is disposed in the ring groove, The battery pack has the main body cylindrical portion and the closing portion connected via the packing in a sealed structure.

13. 13. The battery pack according to claim 12, The main body cylindrical portion has a cylindrical shape with a rectangular cross section, and four corners are curved surfaces, The battery pack is characterized in that the outer peripheral shape of the stepped protrusion is a shape that follows the inner peripheral surface of the main body cylindrical portion.

Images