Battery pack

Abstract

This battery pack comprises: a frame body having a pair of frame end parts that cover at least a pair of cell end surfaces of a secondary battery cell, and a pair of frame wall parts that are connected to the side surfaces of the pair of frame end parts and cover at least a pair of cell side surfaces of the secondary battery cell; and a metal first plate part having a first plate main surface that covers a cell first main surface of the secondary battery cell, and a pair of first plate side walls that cover the pair of frame wall parts from both sides of the first plate main surface. The frame body is formed of an elastic member. The pair of frame wall parts have first wall protrusions on the outer surface thereof. The first plate part has, on the first plate side wall, first plate hole parts for connecting the first wall protrusions. The pair of frame wall parts are thick in places where the first wall protrusions are formed.

Description

Battery pack

[0001] The present disclosure relates to a battery pack.

[0002] Battery packs containing rechargeable secondary battery cells such as lithium-ion secondary batteries are used in a variety of applications as a power source for driving devices (see, for example, Patent Document 1). Some such battery packs are fixed to the devices and are not replaceable, but in recent years, from the perspectives of environmental protection and recycling, some battery packs are detachable and replaceable.

[0003] Such battery packs are required to be smaller, thinner, and lighter for portability, etc. This makes it difficult to house the battery pack in an exterior case to protect it. To address this issue, a frame that surrounds the periphery of the secondary battery cells could be used.

[0004] However, in a structure in which the cell side surfaces of a secondary battery cell are covered with a frame, if the thickness of the cell side surfaces becomes thin, the cell may bend inward as shown in Figure 20, making it difficult to maintain its shape, which is a problem.

[0005] Japanese Patent Application Laid-Open No. 2005-85543

[0006] One object of the present disclosure is to provide a battery pack capable of maintaining the shape of a frame surrounding a secondary battery cell. Another object is to provide a battery pack capable of holding secondary battery cells while avoiding an increase in size. Note that the description of these objects and objects of the present disclosure does not preclude the existence of other objects and objects. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objects. Furthermore, other objects can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0007] A battery pack according to an embodiment of the present disclosure includes a secondary battery cell having a cell first main surface, a cell second main surface opposite to the cell first main surface, a pair of cell end faces connecting the cell first main surface and the cell second main surface, and a pair of cell side faces connected to edges of the pair of cell end faces; a frame body having a pair of frame end portions covering at least the pair of cell end faces of the secondary battery cell, and a pair of frame wall portions connected to edges of the pair of frame end portions and covering at least the pair of cell side faces of the secondary battery cell; A battery pack comprising a metal first plate portion having a first plate main surface covering one main surface and a pair of first plate side walls covering the pair of frame wall portions on both sides of the first plate main surface, wherein the frame body is formed of an elastic material, the pair of frame wall portions form first wall protrusions on their outer surfaces, the first plate portion forms first plate hole portions in the first plate side walls that connect the first wall protrusions, and the pair of frame wall portions form thick portions at the locations where the first wall protrusions are formed.

[0008] With the above configuration, the formation of a first wall protrusion protruding from the surface of a pair of frame wall portions of the frame body serves to pull the frame body outward, preventing the frame body from bending inward, and this first wall protrusion can also be used as a connecting structure for engaging with the first plate portion.

[0009] 1. A perspective view showing a battery pack according to a first embodiment. 1. A perspective view of the battery pack of FIG. 1, seen from diagonally below. 2. An exploded perspective view of the battery pack of FIG. 1 with the label removed. 3. An exploded perspective view of the battery pack of FIG. 1. 4. An exploded perspective view of the battery pack of FIG. 2. 5. A plan view showing the bottom view of the battery pack according to the first embodiment of FIG. 2. 6. An enlarged plan view of a main part of the battery pack of FIG. 6. 7. A perspective view showing a frame of the battery pack of FIG. 1. 8. A cross-sectional view of the battery pack of FIG. 1 taken along line IX-IX. 9. An enlarged perspective view of a main part of the battery pack of FIG. 1. 10. A cross-sectional view of the main part of the battery pack of FIG. 2 taken along line XVI-XVI. 11. An enlarged perspective view of the main part of the battery pack of FIG. 12 taken along line XVII-XVII. 12. An enlarged plan view of a corner of the battery pack of FIG. 1. 13. An exploded perspective view of the battery pack of FIG. 14. 14. A cross-sectional view of the battery pack of FIG. 1 taken along line XVII-XVII. 15. An enlarged plan view of a main part showing the rear side of FIG. 7. 16. A cross-sectional view taken along line XIX-XIX of FIG. 3. 21 is a schematic plan view showing a frame of a battery pack according to a comparative example. 22 is a schematic plan view showing a frame of a battery pack according to embodiment 1. 23 is an enlarged perspective view showing a first coupling mechanism with the label removed from FIG. 1. 24 is a schematic side view of the coupling mechanism of FIG. 22. 25 is an enlarged cross-sectional view taken along line XXIV-XXIV of FIG. 3. 26 is an enlarged cross-sectional view taken along line XXV-XXV of FIG. 3. 27 is a schematic cross-sectional view of the battery pack of FIG. 22. 28 is an enlarged perspective view of a main part showing the coupling mechanism of a battery pack according to embodiment 2. 29 is a schematic side view of the battery pack of FIG. 27. 29 is a schematic cross-sectional view of the battery pack of FIG. 27. 29 is an enlarged perspective view of a main part showing the coupling mechanism of a battery pack according to embodiment 3. 30 is a schematic side view of the battery pack of FIG. 30.

[0010] The embodiments of the present disclosure may be specified by the following configurations and features.

[0011] In a battery pack according to another aspect of the present disclosure, in addition to the above aspect, the first wall protrusion is engaged with an open end of the first plate hole.

[0012] In addition, in a battery pack according to another aspect of the present disclosure, in any of the above aspects, the outer shape of the first wall protrusion is formed to follow the inner shape of the first plate hole. With this configuration, the integrated first wall protrusion can perform the bracing function of the frame wall portion and the connecting function of the first plate portion.

[0013] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the first wall protrusion is divided into a first protruding portion that protrudes outward from a portion of the first plate hole and a first connecting portion that connects to the first plate hole at another portion of the first plate hole. With this configuration, the first wall protrusion is divided into portions that respectively perform the bracing function for the frame wall portion and the connecting function for the first plate, making it easier to insert the first wall protrusion into the first plate hole even with some manufacturing tolerances.

[0014] In addition, in a battery pack according to any one of the above embodiments, a space is formed between the first protruding portion and the first connecting portion. This configuration makes it easier to deform the first protruding portion and the first connecting portion in a direction that reduces the space, thereby facilitating insertion into the first plate hole.

[0015] Furthermore, in a battery pack according to another embodiment of the present disclosure, in any of the above embodiments, the first plate hole portion is rectangular and long in one direction, and the first protrusion portion and the first connecting portion are separated in a direction intersecting the longitudinal direction of the first plate hole portion.

[0016] In yet another aspect of the present disclosure, in any of the above battery packs, the battery pack further includes a metal second plate portion having a second plate main surface covering the second cell main surface of the secondary battery cell and a pair of second plate side walls covering the pair of frame wall portions on both sides of the second plate main surface, the pair of frame wall portions having second wall protrusions formed on their outer surfaces at positions different from the first wall protrusions, the second plate portion having second plate hole portions in the second plate side walls connecting the second wall protrusions, the first plate hole portions and the second plate hole portions being offset from each other. With the above configuration, when the first wall protrusions and the second wall protrusions are engaged with the first plate hole portions and the second wall protrusions and the second plate hole portions are engaged with each other, interference between them can be avoided, thereby preventing the frame wall portions from becoming thick.

[0017] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the frame body includes an intra-frame separator separated from an inner surface of at least one of the pair of frame end portions, the intra-frame separator having a first separating surface that abuts at least a portion of the cell end face, and a second separating surface opposite the first separating surface that faces the inner surface of at least one of the pair of frame end portions and forms a buffer space. With the above configuration, by providing an isolated intra-frame separator on the inner surface of the frame end portion of the frame body, it is possible to hold the cell end faces of the secondary battery cells while providing a buffer space and adding the function of absorbing external stress.

[0018] Furthermore, in the battery pack according to another aspect of the present disclosure, in any one of the above aspects, at least one of the pair of frame ends and the intra-frame separator are spaced apart and parallel to each other.

[0019] In a battery pack according to yet another aspect of the present disclosure, in any of the above aspects, the frame body forms a frame connection portion that partially connects at least one of the pair of frame ends and the intra-frame separator, and the buffer space is formed around the frame connection portion. With this configuration, by partially connecting the frame end portion and the frame body separator, the cell end faces of the secondary battery cells are stably held on the back side of the intra-frame separator, maintaining the shape of the frame body, and any external force applied to the frame body can be absorbed by the buffer space around the frame connection portion.

[0020] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the frame body has a U-shape between at least one of the pair of frame ends and the intra-frame separator via the frame connection portion when viewed in cross section in the thickness direction. By forming the frame ends and the intra-frame separator in a U-shape when viewed in cross section, the buffer space formed between the frame ends and the intra-frame separator is more susceptible to elastic deformation at the U-shaped opening, i.e., the opening that opens in one direction, thereby improving shock absorption capacity.

[0021] In a battery pack according to yet another aspect of the present disclosure, in any of the above aspects, the frame connection portion is formed at the middle in the width direction of at least one of the pair of frame end portions. With this configuration, by abutting the frame body against the middle of the cell end face via the frame connection portion, it is possible to stably hold the cell end face while equally forming buffer spaces on both sides of the frame connection portion, thereby achieving an impact absorbing structure.

[0022] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the frame body has one or more intermediate ribs between a side surface in the width direction of the frame end and at least one end of the pair of frame ends. This configuration has the advantage that the intermediate ribs can be disposed in the buffer space to stably hold the secondary battery cells at the cell end faces.

[0023] Furthermore, in the battery pack according to another aspect of the present disclosure, in any one of the above aspects, the frame body is formed of resin.

[0024] In a battery pack according to yet another aspect of the present disclosure, in any of the above aspects, the first plate portion includes a first plate end wall that covers the second isolating surface of the intra-frame separator at an edge of the first plate main surface that intersects with the pair of first plate side walls, and the first plate end wall forms a first plate protrusion between the first plate end wall and the intermediate rib. With this configuration, the intermediate rib and the first plate protrusion come into contact with each other in the buffer space, allowing the cell end surfaces of the secondary battery cells to come into contact with the frame edge of the frame body at multiple points, thereby stably holding the secondary battery cells.

[0025] Furthermore, in any of the above-described battery packs according to another aspect of the present disclosure, the battery pack further includes an adhesive seal covering the periphery of the cell assembly in which the pair of cell side surfaces are covered by the frame.

[0026] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, 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. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, 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, such that multiple elements are shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0027] The battery pack of the present disclosure can be used as a driving power source for portable electronic devices such as smartphones, tablets, music players, and game consoles, as a power source for portable electrical devices such as radios, electric cleaners, and power tools, as a driving power source for mobile objects such as assisted bicycles, electric carts, and electric scooters, as a backup power source for servers in stationary power storage applications, as a power supply device for home, office, and factory use, and as a driving power source for vehicles such as hybrid cars and electric cars. Below, a battery pack used as a driving power source for a game console will be described as one embodiment of the present disclosure.

[0028] [Embodiment 1] A battery pack 100 according to embodiment 1 of the present disclosure is shown in Figures 1 to 19. In these figures, Figure 1 is a perspective view showing the battery pack 100 according to embodiment 1, Figure 2 is a perspective view of the battery pack 100 of Figure 1 seen obliquely from below, Figure 3 is an exploded perspective view of the battery pack 100 of Figure 1 with the label 50 removed, Figure 4 is an exploded perspective view of the battery pack 100 of Figure 1, Figure 5 is an exploded perspective view of the battery pack 100 of Figure 2, Figure 6 is a bottom view of the battery pack 100 of Figure 2, Figure 7 is an enlarged plan view of a main part of the battery pack 100 of Figure 6, Figure 8 is a perspective view showing the frame 20 of the battery pack 100 of Figure 1, Figure 9 is a cross-sectional view of the battery pack 100 of Figure 1 taken along line IX-IX, Figure 10 is an enlarged perspective view of a main part of the battery pack 100 of Figure 1, and Figure 11 is an enlarged perspective view of the battery pack 100 of Figure 10. Fig. 12 is an enlarged perspective view of the battery pack 100 of Fig. 2, Fig. 13 is an enlarged perspective view of the battery pack 100 of Fig. 12 with the label 50 and the second plate 40 removed, Fig. 14 is an enlarged perspective view of a corner of the battery pack 100 of Fig. 1, Fig. 15 is an exploded perspective view of the battery pack 100 of Fig. 14, Fig. 16 is a cross-sectional view of the battery pack 100 of Fig. 1 taken along line XVI-XVI, Fig. 17 is a cross-sectional view of the battery pack 100 of Fig. 1 taken along line XVII-XVII, Fig. 18 is an enlarged plan view of the rear side of the battery pack 100 of Fig. 7, and Fig. 19 is a cross-sectional view of the battery pack 100 of Fig. 3 taken along line XIX-XIX. The battery pack 100 shown in these figures has a plate-like outer shape as shown in Figs. 1 to 3. As shown in FIGS. 4 and 5 , the battery pack 100 is composed of a secondary battery cell 10 , a frame 20 , a first plate portion 30 , and a second plate portion 40 .

[0029] (Secondary Battery Cell 10) The secondary battery cell 10 is a type known as a plate-shaped laminate battery or a pouch battery. While lithium-ion secondary batteries are primarily used for such secondary battery cells 10, rectangular secondary battery cells can also be used as appropriate. Each secondary battery cell 10 has a first cell main surface 11, a second cell main surface 12 opposite the first cell main surface 11, a pair of cell end surfaces 14 connecting the first cell main surface 11 and the second cell main surface 12, and a pair of cell side surfaces 13 intersecting the cell end surfaces 14 and connecting the edges of the first cell main surface 11 and the second cell main surface 12. In the example shown in Figures 4 and 5, the first cell main surface 11 forms the upper surface, and the second cell main surface 12 forms the lower surface. Furthermore, the pair of cell end surfaces 14 form the longitudinal end surfaces of the first cell main surface 11 and the second cell main surface 12, and the pair of cell side surfaces 13 form the longitudinal side surfaces. Furthermore, the secondary battery cell 10 is provided with positive and negative electrodes. In the examples of FIGS. 4 and 5, positive and negative electrodes are provided on the cell terminal surface 15 on the inner side (right side in the drawings) of the cell end surface 14, and are isolated from each other.

[0030] (Frame 20) The frame 20 covers the cell side surfaces 13 and cell end surfaces 14 of the secondary battery cells 10. The frame 20 is annular and rectangular, forming a cell storage space 21 for storing the secondary battery cells 10 therein. The frame 20 also has a pair of frame walls 22 that cover at least one pair of cell side surfaces 13 of the secondary battery cells 10. The pair of frame walls 22 are connected at their ends. In the example shown in FIGS. 4 and 5 , the frame 20 includes a pair of frame walls 22 and frame end portions 23 that connect the ends of the pair of frame walls 22. The frame end portions 23 include a frame first end portion 23a that connects one end (left side in the figure) of the pair of frame wall portions 22 to each other, and a frame second end portion 23b that connects the other end (right side in the figure) of the pair of frame wall portions 22 to each other. If necessary, the frame first end portion 23a and the frame second end portion 23b may be formed with protrusions or screw holes for fixing or positioning the battery pack to the device to be driven. 2 and 5, the second frame end 23b may be provided with an external electrode 16 or the like. The external electrode 16 is connected to the electrode of the secondary battery cell 10. Such a frame body 20 is formed from an elastic member. Furthermore, the frame body 20 is constructed from a material with excellent insulating properties, heat resistance, and weather resistance. Preferably, the pair of frame walls 22, the first frame end 23a, and the second frame end 23b that constitute the frame body 20 are integrally molded from a resin or the like. Examples of resins that can be used to constitute the frame body 20 include polycarbonate (PC), polyamide (PA), polypropylene (PP), and ABS resin.

[0031] As described above, the battery pack 100 includes the first plate portion 30 and the second plate portion 40, as shown in Figures 4 and 5. The first plate portion 30 covers the cell first main surface 11 of the secondary battery cell 10 held by the frame body 20. The second plate portion 40 covers the cell second main surface 12 of the secondary battery cell 10 held by the frame body 20.

[0032] (First Plate Portion 30) The first plate portion 30 has a first plate main surface 31, a pair of first plate side walls 32, and a first plate end wall 34. The first plate main surface 31 covers the cell first main surface 11 of the secondary battery cell 10. The pair of first plate side walls 32 cover the pair of frame wall portions 22 on both sides of the first plate main surface 31. The first plate end wall 34 covers the second isolation surface 62 of the intra-frame separator 60 at the edge of the first plate main surface 31 that intersects with the pair of first plate side walls 32.

[0033] The first plate portion 30 is preferably made of a metal plate material. For example, SUS or surface-coated iron can be used as the metal material for the first plate portion 30. The first plate portion 30 is connected to the frame body 20 by a first connecting structure. The first plate portion 30 is fixed to the first cell main surface 11 of the secondary battery cell 10 via a fixing means. The fixing means can be double-sided tape or a label. A sticker or tape without information such as the battery pack specifications printed on its surface may also be used.

[0034] (Second Plate Portion 40) The second plate portion 40 has a second plate main surface 41, a pair of second plate side walls 42, and a second plate end wall. The second plate main surface 41 covers the second cell main surface 12 of the rechargeable battery cell 10. The pair of second plate side walls 42 cover the pair of frame wall portions 22 on both sides of the second plate main surface 41. The second plate end wall covers the second isolation surface 62 of the intra-frame separator 60 at the edge of the second plate main surface 41 that intersects with the pair of second plate side walls 42.

[0035] The second plate portion 40 is also preferably made of a metal plate material. As with the first plate portion 30, the metal material for the second plate portion 40 can be, for example, stainless steel or surface-coated iron. The second plate portion 40 is connected to the frame 20 by a second connecting structure. The second plate portion 40 is fixed to the second cell main surface 12 of the secondary battery cell 10 via a second adhesive body 52. ​​Double-sided tape can be used as the second adhesive body 52.

[0036] (Fixing Means) The fixing means fixes the first plate portion 30 to the cell first main surface 11 of the secondary battery cell 10. Such fixing means can be a first adhesive body attached between the cell first main surface 11 of the secondary battery cell 10 and the first plate main surface 31 of the first plate portion 30. Such a first adhesive body can easily fix the first plate portion 30 to the cell first main surface 11, allowing the first plate portion 30 to follow the expansion of the secondary battery cell 10. Double-sided tape can be used as the first adhesive body.

[0037] (Label 50) The fastening means for fastening the first plate portion 30 to the secondary battery cell 10 is not limited to the first adhesive material. For example, the fastening means may be an adhesive label 50 wrapped around the cell assembly 1, which includes the first plate portion 30 covering the first cell main surface 11 of the secondary battery cell 10, the second plate portion 40 covering the second cell main surface 12, and the frame 20 covering the pair of side surfaces. The examples in FIGS. 1 to 5 show an example in which the label 50 is used as the fastening means. The label 50 is preferably made of an insulating material such as paper or resin. By wrapping the cell assembly 1 with the label 50 after assembling the secondary battery cell 10, the frame 20, the first plate portion 30, and the second plate portion 40, the first plate portion 30 can be easily fastened to the secondary battery cell 10. Furthermore, the entire battery assembly, including not only the first plate portion 30 but also the first plate portion 30, can be held together. Furthermore, covering most of the area of ​​the metallic first plate portion 30 and second plate portion improves insulation. Furthermore, if the metal first plate portion 30 and second plate portion 40 have sharp edges, they may be damaged when they come into contact with other components during assembly, etc., but by covering them with label 50, there is an advantage that the exposure of the edges is reduced, thereby increasing safety.

[0038] As described above, the fixing means can be the first adhesive body or the label 50. Either the first adhesive body or the label 50 may be used, or both may be used in combination. Regarding the illustration of the label 50, in the examples of exploded perspective views such as Figures 3 to 5, the label 50 is shown in a folded state for convenience of drawing, but in actual assembly, the label 50 is folded in a rolled-up state from a flat state, following a known label application process.

[0039] (Bumper Structure) Generally, battery packs containing secondary battery cells have often been fixed to the device they are powering, such as smartphones, and are therefore not replaceable. However, in recent years, from the perspectives of environmental protection and recycling, there has been a demand for battery packs to be detachable and replaceable. However, when a battery pack is detachable from the device it is powering, a protective structure is required to prevent stress from being transmitted to the secondary battery cells inside the battery pack and causing damage when an external force is applied, such as when the battery pack is accidentally dropped.

[0040] However, from the viewpoint of portability and weight reduction of the battery pack itself and the device to be driven by the battery pack, there is also a demand for a smaller and thinner battery pack. From another viewpoint, there is also a demand for lower costs. Due to these constraints, the space and cost available for adding a structure to protect the secondary battery cells from external forces such as impacts have been limited. Therefore, it has been difficult to achieve both the conflicting demands of protecting the secondary battery cells and the demands for a smaller and lower-cost battery pack.

[0041] In contrast, the battery pack 100 according to the present disclosure does not house the secondary battery cells 10 in an outer case such as a plastic case, but instead holds them in a frame body 20, thereby eliminating the need for an outer case and making it possible to make the battery pack 100 smaller and thinner.

[0042] Furthermore, when the secondary battery cells are held by a frame, the frame is exposed. Therefore, if external stress is applied, such as when the battery pack is accidentally dropped, the external force applied to the frame is directly transmitted to the secondary battery cells, potentially damaging the secondary battery cells. To avoid this, it is possible to provide a gap or cushioning material between the frame and the secondary battery cells. However, this configuration has the problem that the frame and the secondary battery cells are spaced apart, making it difficult to stably hold the secondary battery cells.

[0043] Therefore, in the battery pack 100 according to the present disclosure, a bumper structure is provided on the frame body 20 to hold the rechargeable battery cells 10 and protect them from external forces. That is, a double structure is provided with an in-frame separator 60 inside the frame end 23, forming a buffer space SP1 between the frame end 23 and the in-frame separator 60. When stress is applied, the buffer space SP1 deforms to relieve the stress and protect the rechargeable battery cells 10. This provides protection from external stress as if a bumper were provided on the cell end surface 14 of the rechargeable battery cell 10. Meanwhile, under normal conditions, the in-frame separator 60 can stably hold the rechargeable battery cells 10 within the frame body 20.

[0044] Furthermore, the problem of the frame body 20 losing its shape due to the formation of the buffer space SP1 is solved by providing a frame connection portion 64 partially within the buffer space SP1. That is, while providing the buffer space SP1 on one of the cell end faces 14, the frame connection portion 64 is provided within the buffer space SP1 to bridge the frame body 20 and the secondary battery cells 10 within the buffer space SP1. This stably holds the secondary battery cells 10, and when an external force is applied to the frame body 20, the external force is absorbed to some extent by the buffer space SP1, preventing the stress from being directly transmitted to the secondary battery cells 10. In this way, the conflicting goals of holding the secondary battery cells 10 and protecting them from external forces are simultaneously achieved. The specific structure will be described in detail below.

[0045] (Buffer space SP1) A buffer space SP1 is formed at least partially between at least one of the pair of cell end faces 14 and at least one of the pair of frame end faces 23. By providing the buffer space SP1, even if an unintended external force is applied to the frame end face 23 when the battery pack 100 is dropped, the buffer space SP1 formed between the frame end face 23 and the cell end face 14 deforms the frame body 20, partially mitigating the impact force and preventing direct application of stress to the secondary battery cells 10, thereby protecting them.

[0046] (Intra-frame separator 60) The frame body 20 includes an intra-frame separator 60 that is separated from the inner surface of at least one of the pair of frame end portions 23. The intra-frame separator 60 has a first separating surface 61 and an opposite second separating surface 62. The first separating surface 61 abuts against at least a portion of the cell end surface 14. The second separating surface 62 faces the inner surface of at least one of the pair of frame end portions 23 to form a buffer space SP1. Furthermore, the frame end portions 23 and the intra-frame separator 60 are separated in parallel. By providing the separated intra-frame separator 60 on the inner surface of the frame end portions 23 of the frame body 20 in this manner, the cell end surfaces 14 of the secondary battery cells 10 are supported while providing the buffer space SP1, thereby providing the function of absorbing external stress. In the example shown in Figures 6 to 8, the intra-frame separator 60 is provided inside the lower first frame end portion 23a of the pair of frame end portions 23. A buffer space SP1 is formed between the first frame end 23a and the second isolation surface 62 of the intra-frame isolation plate 60.

[0047] (Frame connection portion 64) The frame body 20 forms a frame connection portion 64 that partially connects at least one of the pair of frame end portions 23 to the intra-frame separator 60. A buffer space SP1 is formed around this frame connection portion 64. By partially connecting the frame end portion 23 to the intra-frame separator 60 in this manner, the cell end surfaces 14 of the secondary battery cells 10 are stably held on the back side of the intra-frame separator 60, thereby maintaining the shape retention of the frame body 20. Meanwhile, the buffer space SP1 around the frame connection portion 64 makes it possible to absorb stress and protect the secondary battery cells 10 when an external force is applied to the frame body 20.

[0048] 9, it is preferable that, in cross section in the thickness direction, at least one of the pair of frame ends 23 and the intra-frame separator 60 be formed in a U-shape via the frame connection portion 64. By forming the frame end 23 and the intra-frame separator 60 in a U-shape in cross section in this way, the buffer space SP1 formed between the frame end 23 and the intra-frame separator 60 becomes more susceptible to elastic deformation at the U-shaped opening, thereby improving shock absorption capacity.

[0049] The frame connection portion 64 is preferably formed at the widthwise center of at least one of the pair of frame end portions 23. This allows the frame body 20 to abut against the center of the cell end face 14 via the frame connection portion 64, stably holding the cell end face 14, while uniformly forming buffer spaces SP1 on both sides of the frame connection portion 64, thereby providing a shock-absorbing structure. In the example of FIG. 7 , the frame first end portion 23a is connected to the second isolation surface 62 of the in-frame separator 60 at the center and both sides in the widthwise direction. As a result, three points, both ends and the center, of the cell end face 14 of the secondary battery cell 10 are connected to and held by the frame first end portion 23a.

[0050] (Intermediate Rib 66) The frame body 20 can also be provided with one or more intermediate ribs 66 between the widthwise side surfaces of the frame end portions 23 and at least one end of the pair of frame end portions 23. Arranging the intermediate ribs 66 in the buffer space SP1 in this manner allows the secondary battery cells 10 to be stably held by the cell end surfaces 14. Each intermediate rib 66 protrudes from the frame end portion 23 toward the intra-frame separator 60. The end surface of each intermediate rib 66 contacts the intra-frame separator 60 via the first plate portion 30 and the second plate portion 40. Furthermore, it is preferable to limit the area of ​​contact between the intermediate rib 66 and the first plate portion 30 and the second plate portion 40. In the example shown in FIGS. 10 to 13, the contact between each intermediate rib 66 and the first plate portion 30 and the second plate portion 40 is point contact due to abutment by the first plate protrusion 36 and the second plate protrusion 46, respectively. By limiting the contact area in this way, it is possible to hold the rechargeable battery cells 10 in partial contact at key locations while ensuring a wide non-contact area. As a result, when external stress is applied, the buffer space SP1 around the contact area absorbs the impact, limiting the transmission of stress from the limited contact area and protecting the rechargeable battery cells 10. In this way, the conflicting objectives of stably holding the rechargeable battery cells 10 in normal times while limiting the transmission of stress to the rechargeable battery cells 10 in emergencies are achieved.

[0051] It is preferable to arrange multiple intermediate ribs 66 at separate intervals. In the examples shown in FIGS. 7 and 10 to 13, four intermediate ribs 66 are arranged symmetrically in the width direction of the frame first end portion 23a. The spacing between adjacent intermediate ribs 66 may be constant or may vary. The heights of the intermediate ribs 66 in the depth direction may also vary. In the examples shown in FIGS. 10 to 13, the two intermediate ribs 66 on the left side of the figure are higher (toward the front in the figure), and the two intermediate ribs 66 on the right side are lower (toward the back in the figure), offset from each other. By arranging the multiple intermediate ribs 66 at different heights in this way, the wide cell end faces 14 of the rechargeable battery cells 10 can be efficiently held even with a limited contact area.

[0052] (Frame protrusion 70) Furthermore, the frame body 20 can be formed with a frame protrusion 70 on at least one of the pair of frame end portions 23. The frame protrusion 70 is provided in a plate shape that protrudes outward along the width direction of the frame end portion 23. By having the frame protrusion 70 protrude outward from the frame end portion 23 in this way, if the battery pack 100 is dropped from the frame end portion 23 side, the protruding frame protrusion 70 is more likely to come into contact with the floor or the like first. By deforming or breaking the frame protrusion 70, the impact can be absorbed, reducing the stress transmitted to the secondary battery cells 10, thereby providing protection.

[0053] The frame protrusion 70 is preferably formed with a width narrower than the width of the frame end 23. In the example shown in FIG. 7 and other figures, the frame protrusion 70, which is narrower than the width of the frame first end 23a, is centered in the width direction of the frame first end 23a. The frame protrusion 70 may also be reinforced with a protruding rib 72. In the examples shown in FIGS. 7, 12, and 13, a plurality of right-angled triangular protruding ribs 72 are provided only on the back side of the plate-shaped frame protrusion 70 to reinforce the connection between the frame protrusion 70 and the frame first end 23a. On the other hand, as shown in FIGS. 1, 3, 10, and 11, the front side of the frame protrusion 70 does not have a protruding rib 72. This configuration allows the frame protrusion 70 to maintain a certain level of strength while also making it easier for the frame protrusion 70 to be intentionally broken when stress is applied, such as during a drop, thereby providing a structure that is more likely to provide shock absorption.

[0054] The plate-shaped corners of the frame protrusions 70 can also be positioned offset from the positions of the intermediate ribs 66. By protruding the frame protrusions 70, the likelihood that the corners of the frame protrusions 70 will come into contact with the floor or other surface when the battery pack 100 is dropped from the frame end 23 side increases. In this case, if the intermediate rib 66 is positioned above the corners, stress applied to the corners is likely to be directly transmitted to the intermediate rib 66 and affect the cell end faces 14 of the rechargeable battery cells 10. Therefore, by adjusting the width of the frame protrusions 70 so that the corners of the frame protrusions 70 are not positioned directly below the intermediate ribs 66, in other words, so that the ends of the plate-shaped frame protrusions 70 do not overlap the intermediate ribs 66, it is possible to prevent stress from being directly transmitted to the rechargeable battery cells 10. In the example shown in FIG. 7 , the ends of the frame protrusions 70 are positioned to the left of the right-most intermediate rib 66. This increases the probability that the corners of the plate-shaped frame protrusions 70 will come into contact with the floor surface or the like when dropped, while offsetting these corners from the intermediate ribs 66 prevents stress applied to the corners from being directly transmitted to the secondary battery cells 10 via the intermediate ribs 66, thereby reducing the stress applied to the secondary battery cells 10 and providing protection.

[0055] Furthermore, the frame protrusion 70 may be provided at the center in the thickness direction of the frame end 23, or may be positioned eccentrically from the center. In particular, with regard to its relationship with the frame connection 64, it is preferable to position the frame protrusion 70 and the frame connection 64 eccentrically in the thickness direction of the frame end 23. By intentionally positioning the frame protrusion 70 and the frame connection 64 eccentrically rather than in a straight line, it is possible to prevent a situation in which, when the battery pack 100 is dropped from the frame end 23 side, an impact applied to the protruding frame protrusion 70 is transmitted directly to the secondary battery cells 10 via the frame connection 64.

[0056] 9, the frame connection portion 64 connecting the U-shaped frame end portion 23 and the intra-frame separator 60 is located on the right side in the figure, while the frame protrusion portion 70 is located on the underside of the first frame end portion 23a, shifted from the center to the left. By positioning the frame protrusion portion 70 in the thickness direction of the frame body 20 away from the frame connection portion 64 in this way, stress propagated from outside the frame body 20 when, for example, the battery pack 100 is dropped is first transmitted from the frame protrusion portion 70 in a crossing direction and then transmitted from the second isolation surface 62 of the intra-frame separator 60 to the rechargeable battery cells 10 via the frame connection portion 64. This prevents the impact of the drop from being directly applied to the cell end faces 14 of the rechargeable battery cells 10, and, together with the shock absorption capacity of the U-shaped buffer space SP1, further protects the rechargeable battery cells 10.

[0057] (Second Buffer Space SP2) Furthermore, a second buffer space SP2 can be formed between the intra-frame separator 60 and the cell end surface 14 of the rechargeable battery cell 10 on the first isolation surface 61 side of the intra-frame separator 60. The second buffer space SP2 is formed on the back side of the portion where the frame connection portion 64 is provided. In the example of the cross-sectional view of FIG. 9 , the shape of the cell end surface 14 of the rechargeable battery cell 10 is not flat at the bottom in cross section, but has a flat area on one side (the left side in the figure) and a gently curved surface that slopes upward toward the other side. In this way, the entire first isolation surface 61 of the intra-frame separator 60 does not contact the cell end surface 14 of the rechargeable battery cell 10, and a portion of the cell end surface 14 is held in partial contact while providing a non-contact space. This further lengthens the path for stress to be transmitted to the rechargeable battery cell 10 when an external force is applied, such as when the battery pack 100 is dropped from the frame end 23 side, thereby improving protection. That is, the stress propagates from the frame protrusion 70 to the frame first end 23a, the frame connection 64, from left to right, and then from right to left through the intra-frame separator 60 to the cell end face 14 of the secondary battery cell 10. In addition to the stress being transmitted in a detour along this zigzag propagation path, the stress is also absorbed and alleviated in the U-shaped buffer space SP1 and the second buffer space SP2, thereby further protecting the secondary battery cell 10 by reducing the propagated stress.

[0058] (Corner Recesses 68) The frame body 20 can also have corner recesses 68 formed at the corners between the frame end portion 23 and the frame wall portion 22. Furthermore, corner ribs 69 defining an internal space may be formed inside these corner recesses 68. With this configuration, even if the battery pack 100 is dropped from a corner of the frame body 20, the corner ribs 69 formed on the frame body 20 collapse to absorb the impact, providing the advantage of reducing stress on the rechargeable battery cells 10 and protecting them. In the example of FIG. 14 , the corners between the frame first end portion 23 a and the frame wall portion 22 of the frame body 20 are chamfered, forming frame recesses that are carved inward, and two separate corner ribs 69 are further formed in the frame recesses. With this configuration, if the frame body 20 is dropped from a corner, the corner recesses 68 and corner ribs 69 formed at the corners collapse to absorb the impact, thereby protecting the rechargeable battery cells 10 held by the frame body 20.

[0059] (First Plate Side Wall 32, Second Plate Side Wall 42) On the other hand, the first plate portion 30 has a first plate side wall 32 on a side surface in the longitudinal direction, as shown in Figures 4, 5, 15, etc. Similarly, the second plate portion 40 has a second plate side wall 42 on a side surface in the longitudinal direction.

[0060] (First Plate Protrusion 36) As shown in Figures 15 and 16, the first plate end wall 34 forms a first plate protrusion 36 between itself and the intermediate rib 66. This configuration allows the intermediate rib 66 and the first plate protrusion 36 to abut in the buffer space SP1, stably holding the cell end surfaces 14 of the secondary battery cells 10 in contact with the frame end 23 of the frame body 20 at multiple locations. Furthermore, if the intermediate rib 66 were to protrude to abut the first plate protrusion 36, the mold portion for molding the intermediate rib 66 in the resin molding die for forming the frame body 20 would have to be thin. However, by protruding the metal first plate end wall 34, the thickness of the die can be ensured, resulting in improved mold molding reliability and durability. Such a first plate protrusion 36 can be easily formed by press working or punching.

[0061] (Second plate protrusion 46) Similarly to the first plate end wall 34, the second plate end wall also has a second plate protrusion 46 formed between the corresponding intermediate rib 66, as shown in the cross-sectional view of Figure 17. With this configuration, the intermediate rib 66 and the second plate protrusion 46 abut against each other in the buffer space SP1, allowing the cell end surfaces 14 of the secondary battery cells 10 to come into contact with the frame end 23 of the frame 20 at multiple locations, thereby stably holding them in place. Furthermore, by making the metal second plate end wall protrude, the intermediate rib 66 can be made thinner, which similarly ensures the thickness of the molding die, resulting in the advantage of improving the reliability and durability of the molding process.

[0062] These first plate protrusions 36 and second plate protrusions 46 are provided at positions corresponding to intermediate ribs 66 formed on the frame end portion 23. That is, corresponding to the fact that the multiple intermediate ribs 66 are provided at different heights in the thickness direction of the frame end portion 23, the first plate protrusions 36 and second plate protrusions 46 are also provided at different heights in the thickness direction of the frame body 20. As shown in Figures 18 and 19, when the first plate portion 30 and the second plate portion 40 are connected to the second isolation surface 62 side of the intra-frame separator 60, the first plate protrusions 36 are located on the upper side and the second plate protrusions 46 are located on the lower side. In this way, the contact area between the frame first end portion 23a and the intra-frame separator 60 via the first plate portion 30 and the second plate portion 40 is kept small, and the contact areas are distributed in the thickness direction of the frame body 20 (the vertical direction in the figure) and also in the width direction (the horizontal direction in the figure), so that the wide cell end faces 14 can be abutted at key points and stably held even with a small contact area. Furthermore, by limiting the contact area, it is possible to avoid a situation in which stress is directly transmitted, and to absorb impacts using the surrounding buffer space SP1.

[0063] In the above example, a bumper structure is provided on one side of the cell end face 14, i.e., on the frame first end 23a side. The disclosed example is preferable in terms of volumetric efficiency. However, the disclosure is not limited to this configuration, and a bumper structure may be provided on the frame second end 23b side of the cell end face 14. Also, a bumper structure may be provided on each side of the cell end face 14. Furthermore, the bumper structure is not limited to the cell end face 14, but may also be provided on the cell side face 13. For example, if the secondary battery cell has a horizontally long shape, this is preferable because the narrow side is more susceptible to collisions. In this way, a bumper structure can be provided on the side that needs to be protected, depending on the external shape and internal structure of the secondary battery cell.

[0064] (First plate hole portions 38) The first plate side wall 32 has a plurality of spaced-apart first plate holes 38 formed therein as a first connecting structure for connecting to the frame 20. In the examples shown in Figures 8, 14, and 15, the first plate side wall 32 is partially enlarged near the first plate holes 38. Alternatively, as with the first plate hole 38 located in the middle in Figure 4, the first plate side wall 32 may be partially enlarged around multiple adjacent first plate holes 38. Each of the first plate holes 38 is a rectangular opening that continues from the first plate main surface 31 of the first plate portion 30 to the first plate side wall 32.

[0065] (First wall protrusions 24) The frame body 20 also has first wall protrusions 24 formed on the outer surfaces of the pair of frame wall portions 22 and the intra-frame separator 60 as first connecting structures for connecting to the first plate portion 30. The first wall protrusions 24 are provided at positions corresponding to the first plate holes 38. The first wall protrusions 24 of the frame body 20 are connected to the first plate holes 38 of the first plate portion 30 to connect the frame body 20 to the first plate portion 30. The frame body 20 has thicker walls at the locations of the pair of frame wall portions 22 where the first wall protrusions 24 are formed. This configuration makes it possible to prevent the frame body 20 from bending inward.

[0066] In recent years, the conflicting demands for battery packs—those requiring higher capacity while also being smaller and lighter—have led to the need to increase the volume occupied by secondary battery cells within the battery pack, necessitating the thinning of housing components such as exterior cases. To meet these demands, a structure in which the sides of the secondary battery cells are covered with a resin frame without using an exterior case has been considered. However, as shown in Figure 20 , a problem has arisen in that the frame wall 922 of the battery pack frame 920 is prone to inward bending when the thickness of the resin covering the cell sides becomes thin. In particular, when the frame wall thickness is as thin as about 1 mm, the strength of the frame wall decreases relatively, resulting in poor shape retention and making the frame more prone to inward bending. However, increasing the resin thickness would result in a corresponding increase in the size of the battery pack.

[0067] Therefore, in the present disclosure, by providing multiple regions where the resin is partially thickened, the resin is partially thickened, generating a force that pulls the frame body 20 outward, thereby providing a tensioning effect that resists inward bending, as shown in FIG. 21 . This configuration, which does not require the entire resin to be thickened, can prevent the entire battery pack from becoming larger, thicker, heavier, and more costly. Furthermore, by utilizing the partially thickened resin regions for the first connecting structure with the first plate portion 30 and the second connecting structure with the second plate portion 40, the configuration can be simplified and space-saving can be achieved. In particular, while partially thickening the resin frame wall portion 22 inevitably increases the width of the battery pack, by thickening only the connecting structure portion, the thickened portions are positioned at the through-holes of the first plate hole 38 and the second plate hole 48, allowing the increased thickness to be absorbed by the thickness of the first plate portion 30 and the second plate portion 40. In addition, by using the first plate side wall 32 of the first plate portion 30 as a connecting structure with the first plate portion 30 and the second plate portion 40, the rigidity of the frame body 20 can be increased substantially without using any additional members. Furthermore, by covering the frame wall portion 22 with the first plate side wall 32 of the first plate portion 30 as shown in Figures 22 and 23, it is possible to prevent the frame wall portion 22 from bending outward.

[0068] 20, for the purpose of explanation, the deflection occurring only in the frame wall portion 922 on the long side of the sides constituting the frame body 920 is exaggerated. In reality, deflection also occurs in the frame end portion 924 on the short side, but since deflection is more likely to occur as the side becomes longer, the frame end portion 924 is not shown.

[0069] Furthermore, the first connecting structure for connecting the frame body 20 and the first plate portion 30 can be provided not only on the long side of the battery pack 100 but also on the short side. However, depending on the required strength and the method of joining the frame body 20 and the first plate portion 30, it is not necessarily required to provide it on both of the pair of short sides, and it may be provided on only one side. In the example of Figures 4 and 5, the first connecting structure is provided only on the frame first end portion 23a side, and not on the frame second end portion 23b side. The same applies to the second connecting structure for connecting the frame body 20 and the second plate portion 40, which will be described later.

[0070] The first wall protrusions 24 are engaged with the lower ends of the first plate holes 38 to prevent the first plate 30 from lifting and maintain the connected state. The outer shape of the first wall protrusions 24 is formed to roughly match the inner shape of the first plate holes 38. In the examples shown in Figures 3, 4, 5, etc., a plurality of first wall protrusions 24 are formed at intervals on the lower end of the outer surface of each frame wall 22. As shown in Figure 24, each first wall protrusion 24 is formed in a right-angled triangular shape in a cross section intersecting the longitudinal direction, with its hypotenuse tapering upward. The first wall protrusions 24, which are right-angled triangular in cross section, have a first flat surface on the lower surface continuing from the first inclined surface constituting the hypotenuse. The inner surface of the first plate hole 38 abuts against this first flat surface to engage the first plate side wall 32 with the frame wall 22. The frame body 20 having this structure is press-fitted from below between the first plate side walls 32, causing the first inclined surfaces of the first wall projections 24 to widen the gap between the first plate side walls 32, or deforming the pair of frame wall portions 22 to narrow the gap by reaction, thereby engaging the first wall projections 24 with the first plate holes 38. In this state, the height, i.e., the vertical length, of the first plate portions 30 is made to match the height, i.e., the vertical length, of the first wall projections 24 so that the first plate portions 30 are not displaced in the up-down direction relative to the frame body 20.

[0071] (Second plate hole portions 48) Similarly, the second plate portion 40 has a second plate side wall 42 on a side surface in the longitudinal direction. The second plate side wall 42 also has a plurality of spaced-apart second plate holes 48 formed therein as a second connecting structure for connecting to the frame body 20. In the examples shown in Figures 8, 14, and 15, the second plate side wall 42 is similarly formed larger in part near the second plate hole portions 48. Each second plate hole portion 48 is a rectangular opening that continues from the main surface of the second plate portion 40 to the second plate side wall 42.

[0072] (Second Wall Protrusions 27) The frame body 20 also has a plurality of spaced-apart second wall protrusions 27 formed on the outer surfaces of the pair of frame wall portions 22 and the intra-frame separator 60. The second wall protrusions 27 are provided at positions corresponding to the second plate holes 48, respectively. In a cross section intersecting the longitudinal direction, each second wall protrusion 27 is formed in the shape of a right triangle whose hypotenuse tapers downward, as shown in FIG. 25 . The second wall protrusions 27, which are shaped like a right triangle in cross section, have an upper surface that continues from the second inclined surface that forms the hypotenuse, as a second flat surface. The inner surface of the second plate hole 48 abuts against this second flat surface, thereby engaging the second plate side wall 42 with the frame wall portion 22. The frame body 20 having this structure is press-fitted from above between the second plate side walls 42, causing the second inclined surfaces of the second wall protrusions 27 to widen the gap between the second plate side walls 42, or deforming the pair of frame wall portions 22 to narrow the gap by a reaction, thereby engaging the second wall protrusions 27 with the second plate holes 48. As shown in Figure 25, the height, i.e., the vertical length, of the second plate holes 48 is longer than the height, i.e., the vertical length, of the second wall protrusions 27 so that the second plate portion 40 is displaced upward when connected to the frame body 20. This makes it possible to displace the second plate portion 40 up and down by a stroke amount DS due to the difference in height between the second plate holes 48 and the second wall protrusions 27.

[0073] Furthermore, the first and second connecting structures formed by the first wall protrusion 24 and the first plate hole 38, and the second wall protrusion 27 and the second plate hole 48 can be added not only to the longitudinal side surfaces of the battery pack 100, but also to the end surfaces. In the example of Fig. 16, the first plate hole 38 and the second plate hole 48 are similarly provided in the first plate end wall 34 of the first plate portion 30 and the second plate end wall 44 of the second plate portion 40.

[0074] 14, 15, etc., the frame body 20 has the first wall protrusion 24 and the second plate hole 48 offset from each other in the vertical direction on the outer surface of the frame wall 22. With this arrangement, as shown in FIGS. 24, 25, etc., when the first wall protrusion 24 is engaged with the first plate hole 38 and the second wall protrusion 27 is engaged with the second plate hole 48, even if the portions of the first plate side wall 32 and the second plate side wall 42 where the first plate hole 38 and the second plate hole 48 are formed are enlarged, interference between them is avoided, and a situation in which the frame wall 22 becomes thicker outward is avoided (third wall protrusion 28).

[0075] Furthermore, the frame wall portion 22 forms a third wall protrusion 28 in the region of the first plate sidewall 32 and the second plate sidewall 42 where there are no enlarged perimeters of the first plate hole 38 and the second plate hole 48. The thickness of the third wall protrusion 28 is set to be flush with the side surface of the first plate portion 30 and the second plate portion 40 when they are connected to the frame body 20, i.e., approximately the same as the thickness of the first plate sidewall 32 and the second plate sidewall 42, or slightly thicker by a margin. By forming the third wall protrusion 28, the frame body 20 can be reinforced by partially thickening it. In addition, as shown in the perspective view of FIG. 8 , forming the third wall protrusion 28 on the frame body 20 at a position spaced apart from the first wall protrusion 24 and the second wall protrusion 27 has the advantage of adding strength to resist deformation of the frame body 20.

[0076] [Embodiment 2] In the above example, as shown in the cross-sectional view of Figure 26, a common first wall protrusion 24 is used to brace the frame wall portion 22 outward to prevent bending and to connect the first plate portion 30. However, the present disclosure is not limited to this configuration. The first wall protrusion may be divided, and the bracing function of the frame wall portion and the connecting function of the first plate portion may be performed by separate members. Such an example is shown in Figures 27 to 29 as a battery pack 200 according to embodiment 2. In these figures, components similar to those in embodiment 1 described above are designated by the same reference numerals, and detailed descriptions will be omitted where appropriate. Note that the label 50 is not shown in Figure 27.

[0077] The first wall projection 24B shown in Figures 27 to 29 is composed of a first protruding portion 25 and a first connecting portion 26. The first protruding portion 25 functions to brace the frame wall portion 22B outward. Meanwhile, the first connecting portion 26 is engaged with the first plate hole 38 of the first plate portion 30 to connect the first plate portion 30 to the frame body 20B. Specifically, the underside of the first connecting portion 26 abuts the open end of the first plate hole 38, preventing the first plate portion 30 from lifting up. The first connecting portion 26 can perform its connecting function as long as it has an area that abuts the open end of the first plate hole 38. In other words, the upper side of the first connecting portion 26 is not necessary for performing the connecting function. The first wall projection 24 according to embodiment 1 shown in the cross-sectional view of Figure 26 also functions to brace the frame wall portion 22 outward only in the area surrounded by the dashed circle. In this way, the bracing function and the connecting function are partially achieved even in the integrated first wall projection 24. Therefore, the first connecting portion 26 in Figure 29 fully achieves the function of connecting with the first plate portion 30.

[0078] As shown in FIG. 27 , even if the first wall projection 24B is divided into the first overhanging portion 25 and the first connecting portion 26, the first wall projection 24 can perform the same function as the first wall projection 24 in which these are integrally formed as shown in FIGS. 22 and 23 . On the other hand, dividing the first wall projection 24B into the first overhanging portion 25 and the first connecting portion 26 has the advantage of facilitating connection to the first plate portion 30. The integral first wall projection 24 as in the first embodiment described above is inserted into and connected to a first plate hole 38, as shown in the cross-sectional view of FIG. 26 . Here, the first wall projection 24 is formed integrally with the resin frame wall portion 22. Furthermore, the first plate hole 38 of the metal first plate portion 30 is formed by a punching process or the like. While manufacturing tolerances occur during these processes, if the maximum diameter D1 of the first wall projection 24 exceeds the minimum diameter D2 of the first plate hole 38, the first wall projection 24 cannot be inserted into the first plate hole 38 as is, and a press fit is required. 29, the first wall projection 24B is divided into a first protruding portion 25 and a first connecting portion 26, and a separation space SP3 is formed between the first protruding portion 25 and the first connecting portion 26. This makes it easier to deform the space between the first protruding portion 25 and the first connecting portion 26 in a direction that reduces the separation space SP3. As a result, there is an advantage that the insertion into the first plate hole 38 can be performed smoothly even with some manufacturing tolerances.

[0079] [Embodiment 3] In the above-described embodiment 2, an example in which the first protrusion 25 and the first connecting portion 26 are inserted into each of the first plate holes 38 has been described. However, the present disclosure is not limited to this configuration. A configuration in which only the first protrusions are inserted into some of the first plate holes and only the first connecting portions are inserted into the other first plate holes may be used. Such an example is shown in Figures 30 and 31 as a battery pack 300 according to embodiment 3. In these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0080] 30 and 31 , only the first protrusion 25C is inserted into the first plate hole 38 on the right side, and only the first connecting portion 26C is inserted into the first plate hole 38 on the left side. This configuration has the advantage that the first wall protrusion 24C on the frame wall 22C is smaller, making it easier to insert the first protrusion 25C and the first connecting portion 26C into each of the first plate holes 38. Note that although the right first plate hole 38 does not function to connect the frame body 20C and the first plate 30, the left first plate hole 38 does, providing the necessary connecting strength.

[0081] In the above examples of embodiments 2 and 3, the first connecting structure that connects the frame wall portion 22 to the first plate portion 30 has been described, but it goes without saying that the second wall protrusion 27 that constitutes the second connecting structure that connects it to the second plate portion 40 can also be configured by dividing it into a second protruding portion and a second connecting portion, similar to the first wall protrusion 24.

[0082] In the above example, the battery pack is used as a power source for a portable electronic device such as a game console. However, the present disclosure is not limited to this. The battery pack can also be used for other purposes, such as attaching it to an electrical device to be driven and supplying power to the electrical device. Examples of electrical devices include portable electrical devices and moving objects such as electric vehicles and electric carts. In such electrical devices, when the remaining capacity of the battery pack becomes low or the battery pack deteriorates over time, the battery pack can be replaced to continue using the electrical device. However, the present disclosure is not limited to replaceable battery packs that mainly house secondary battery cells, but can also be applied to battery packs in which secondary battery cells are housed within the housing of the electrical device. In the present disclosure, a battery pack is defined as a battery pack that houses secondary battery cells in a case, and also includes battery packs in which secondary battery cells for driving the electrical device are built into the housing of the electrical device itself. In other words, the present disclosure is not limited to replaceable battery packs, but can also be applied to electrical devices that house secondary battery cells.

[0083] The battery pack according to the present disclosure can be suitably used as a power source for driving portable electronic terminals such as game consoles, as a power source for radios, and as a power source for portable electrical equipment such as electric cleaners and power tools, as a power source for driving mobile objects such as electric-assisted bicycles, electric carts and electric scooters, as a backup power source for servers and the like, and as a stationary power storage device for home, office and factory use, etc.

[0084] DESCRIPTION OF SYMBOLS 100, 200, 300... Battery pack 1... Cell assembly 10... Secondary battery cell 11... Cell first main surface 12... Cell second main surface 13... Cell side surface 14... Cell end surface 15... Cell terminal surface 16... External electrode 20, 20B, 20C... Frame body 21... Cell storage space 22, 22B, 22C... Frame wall portion 23... Frame end portion 23a... Frame first end portion 23b... Frame second end portion 24, 24B, 24C... First wall protrusion 25, 25C... First protruding portion 26, 26C... First connecting portion 27... Second wall protrusion 28... Third wall protrusion 30... First plate portion 31... First plate main surface 32... First plate side wall 34... First plate end wall 36... First plate protrusion 38... First plate hole portion 40... Second plate portion 42... Second plate side wall 44...Second plate end wall 46...Second plate protrusion 48...Second plate hole 50...Label 52...Second adhesive body 60...Intra-frame separator 61...First isolation surface 62...Second isolation surface 64...Frame connection portion 66...Intermediate rib 68...Corner recess 69...Corner rib 70...Frame protrusion 72...Protruding rib 920...Frame body 922...Frame wall portion 924...Frame end portion DS...Stroke amount SP1...Buffer space SP2...Second buffer space SP3...Separation space D1...Maximum diameter of first wall protrusion 24 D2...Minimum diameter of first plate hole 38

Claims

1. A battery pack comprising: a secondary battery cell having a cell first main surface; a cell second main surface opposite to the cell first main surface; a pair of cell end faces connecting the cell first main surface and the cell second main surface; and a pair of cell side surfaces connected to edges of the pair of cell end faces; a frame body having a pair of frame end portions covering at least the pair of cell end faces of the secondary battery cell; and a pair of frame wall portions connected to edges of the pair of frame end portions and covering at least the pair of cell side faces of the secondary battery cell; and a metal first plate portion having a first plate main surface covering the cell first main surface of the secondary battery cell and a pair of first plate side walls covering the pair of frame wall portions on both sides of the first plate main surface, wherein the frame body is an elastic member, the pair of frame wall portions have first wall protrusions on their outer surfaces, and the first plate portion has first plate hole portions connecting the first wall protrusions to the first plate side walls, and the pair of frame wall portions are thick-walled at the locations where the first wall protrusions are provided.

2. A battery pack according to claim 1, wherein the first wall protrusion is engaged with the open end of the first plate hole.

3. A battery pack according to claim 1, wherein the outer shape of the first wall protrusion conforms to the inner shape of the first plate hole.

4. A battery pack as claimed in claim 1, wherein the first wall protrusion is divided into a first protruding portion that is part of the first plate hole and protrudes outwards, and a first connecting portion that is another part of the first plate hole and connects to the first plate hole.

5. A battery pack according to claim 4, wherein a separation space (SP3) is provided between the first protruding portion and the first connecting portion.

6. A battery pack as claimed in claim 4, wherein the first plate hole portion is rectangular and long in one direction, and the first protrusion portion and the first connecting portion are separated in a direction intersecting the longitudinal direction of the first plate hole portion.

7. A battery pack as claimed in claim 1, further comprising a metal second plate portion having a second plate main surface covering the second cell main surface of the secondary battery cell, and a pair of second plate side walls covering the pair of frame wall portions on both sides of the second plate main surface, wherein the pair of frame wall portions have second wall protrusions on their outer surfaces at positions different from the first wall protrusions, and the second plate portion has second plate hole portions in the second plate side walls that connect the second wall protrusions, and the first plate hole portions and the second plate hole portions are arranged offset from each other.

8. A battery pack as claimed in claim 1, wherein the frame body is provided with an intra-frame separator isolated from the inner surface of at least one of the pair of frame ends, the intra-frame separator having: a first separating surface that abuts against at least a part of the cell end face; a second separating surface that is the surface opposite to the first separating surface and faces the inner surface of at least one of the pair of frame ends; and a buffer space between the first separating surface and the second separating surface.

9. A battery pack according to claim 8, wherein at least one of the pair of frame ends and the frame internal separator are separated and parallel to each other.

10. A battery pack as claimed in claim 9, wherein the frame body has a frame connection part that partially connects at least one of the pair of frame ends to the frame separator, and the buffer space (SP1) is provided around the frame connection part.

11. A battery pack as claimed in claim 10, wherein, in a cross-sectional view of the thickness of the frame body, at least one of the pair of frame ends and the in-frame separator surround the buffer space via the frame connection part, with an opening in one direction.

12. A battery pack according to claim 10, wherein the frame connection portion is disposed at the middle of the width of at least one of the pair of frame ends.

13. A battery pack according to claim 10, wherein the frame body has one or more intermediate ribs between a side surface of the frame end across the width and at least one end of the pair of frame ends.

14. A battery pack according to claim 13, wherein the frame is made of resin.

15. A battery pack as claimed in claim 14, wherein the first plate portion has a first plate end wall covering the second isolation surface of the frame separator at an edge of the first plate main surface that intersects with the pair of first plate side walls, and the first plate end wall has a first plate protrusion between it and the intermediate rib.

16. A battery pack according to any one of claims 1 to 15, further comprising an adhesive seal covering the periphery of the cell assembly in which the pair of cell side surfaces are covered by the frame.

Images