Battery pack

Abstract

The present invention provides a battery pack capable of holding secondary battery cells without gaps. A battery pack (100) is provided with a battery holder (2) that holds one or more secondary battery cells (1). The battery holder (2) is provided with: a hollow holder tube section (3) that individually accommodates one or more secondary battery cells (1); and a pair of holder lid sections (12, 22) that respectively close the hollow end surfaces of the holder tube section (3). At least one of the pair of holder cover sections (12, 22) is provided with an elastically deformable protrusion section (15) that partially protrudes toward one of the pair of end surfaces of the secondary battery cells (1) housed in the holder tube section (3). A battery holder (2) is configured by joining a first holder (10) and a second holder (20), which are at least bisected in the longitudinal direction of one or more secondary battery cells (1), and in a state in which the first holder (10) and the second holder (20) are joined, a protrusion (15) is configured so as to press the end surfaces of the one or more secondary battery cells (1).

Description

Technical Field

[0001] The present disclosure relates to battery packs. Background Art

[0002] To power electrical equipment using rechargeable secondary battery cells, such as lithium-ion secondary batteries, a battery pack is used (e.g., Patent Document 1), which houses multiple secondary battery cells in an outer casing. In such a battery pack, the secondary battery cells are held by a battery holder. Due to manufacturing tolerances within the battery holder itself and the secondary battery cells, the battery holder must be manufactured with sufficient dimensions to accommodate the secondary battery cells.

[0003] However, this structure tends to create gaps when the secondary battery cell is housed in the battery holder, necessitating a structure to suppress shaking. For example, a structure has been adopted in which silicone rubber is sandwiched around the positive electrode portion of the secondary battery cell and screwed in. This method requires another component to suppress the gaps, and there is also the problem of increased labor required to position and screw in the silicone rubber.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-83087

[0007] Patent Document 2: Japanese Patent Application No. 2021-501455 Summary of the Invention

[0008] -Problems to be solved by the invention-

[0009] One of the objects of the present disclosure is to provide a battery pack capable of holding secondary battery cells without gaps.

[0010] -Methods for solving the problem-

[0011] The battery pack according to one embodiment of the present invention comprises: one or more secondary battery cells, each of which extends in one direction and has a pair of end faces intersecting the extension direction; and a battery holder for holding the one or more secondary battery cells, wherein the battery holder comprises: a hollow holder barrel portion for individually accommodating the one or more secondary battery cells; and a pair of holder cover portions, each blocking the hollow end faces of the holder barrel portion, wherein at least any one of the pair of holder cover portions has an elastically deformable protrusion portion, the protrusion portion locally protruding toward any one of the pair of end faces of the secondary battery cells accommodated in the holder barrel portion, and combining a first holder and a second holder that are at least divided into two in the long side direction of the one or more secondary battery cells to form the battery holder, wherein the protrusion is configured to press the end faces of the one or more secondary battery cells when the first holder and the second holder are combined.

[0012] -Effects of the Invention-

[0013] According to the battery pack according to one aspect of the present invention, the secondary battery cell can be held by being sandwiched between the first and second holders along the longitudinal direction of the secondary battery cell, and the end faces of the secondary battery cell can be abutted and held by the protrusions from the longitudinal direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective view showing a battery holder of the battery pack according to the first embodiment.

[0015] Figure 2 Observed from the back Figure 1 A perspective view of the battery holder.

[0016] Figure 3 is Figure 1 An exploded perspective view of a battery pack in which a secondary battery cell and a lead plate are incorporated into a battery holder.

[0017] Figure 4 is Figure 2 An exploded perspective view of a battery pack in which a secondary battery cell and a lead plate are incorporated into a battery holder.

[0018] Figure 5 yes Figure 1 A cross-sectional view of the battery holder at line VV with an enlarged view of the main parts.

[0019] Figure 6 yes Figure 1 A sectional perspective view of the battery holder taken along line VI-VI.

[0020] Figure 7 It is a cross-sectional view of a battery holder according to a comparative example.

[0021] Figure 8 It is shown in Figure 3 A cross-sectional view showing a state in which a secondary battery cell is inserted into a battery holder.

[0022] Figure 9 It is shown in Figure 8 A cross-sectional view showing a state where a secondary battery cell is inserted into a battery holder.

[0023] Figure 10 yes Figure 1 Cross-sectional view at line XX.

[0024] Figure 11 yes Figure 10 Stereoscopic image.

[0025] Figure 12 yes Figure 1 An enlarged perspective view of the battery holder.

[0026] Figure 13 This is a rear view showing the inner surface of the battery holder according to the second embodiment.

[0027] Figure 14 This is a rear view showing the inner surface of the battery holder according to the third embodiment.

[0028] Figure 15 This is a rear view showing the inner surface of the battery holder according to the fourth embodiment.

[0029] Figure 16 This is a rear view showing the inner surface of the battery holder according to the fifth embodiment.

[0030] Figure 17 This is a rear view showing the inner surface of the battery holder according to the sixth embodiment.

[0031] Figure 18 This is a rear view showing the inner surface of the battery holder according to the seventh embodiment.

[0032] Figure 19 This is a rear view showing the inner surface of the battery holder according to the eighth embodiment.

[0033] Figure 20 This is a perspective view of a battery pack according to a ninth embodiment.

[0034] Figure 21 This is a perspective view of a battery pack according to a tenth embodiment.

[0035] Figure 22 yes Figure 21 Exploded perspective view of the battery pack.

[0036] Figure 23 yes Figure 22 A front view of the second retaining member.

[0037] Figure 24 Observed from the back side Figure 22 A front view of the first retaining member. DETAILED DESCRIPTION

[0038] The aspects of the present invention can also be identified by the following structures and features.

[0039] Regarding a battery pack according to another embodiment of the present invention, in the above-described embodiment, the battery holder is configured such that the distance between the pair of holder covers along the longitudinal direction of each secondary battery cell, in a cell storage space formed by the holder tube portion and the pair of holder covers for individually storing the one or more secondary battery cells, is longer than the length of each of the one or more secondary battery cells, and the length of the cell storage space along the longitudinal direction of each secondary battery cell, as defined by the front end of the protrusion, is shorter than the length of each of the one or more secondary battery cells. With this configuration, the distance between the pair of holder covers within the cell storage space for storing the secondary battery cells is longer than the secondary battery cells, taking into account manufacturing tolerances, and the provision of the elastically deformable protrusions to press and stably retain the secondary battery cells, thereby preventing shaking caused by gaps.

[0040] In another embodiment of the battery pack of the present invention, in any of the above embodiments, the protrusion is integrally formed with one of the pair of retainer covers. With this structure, the protrusion is formed on only one of the retainer covers, allowing the secondary battery cell to be stably held in the cell storage space.

[0041] Furthermore, regarding a battery pack according to another aspect of the present invention, in any of the above aspects, a pair of slits is formed in one of the pair of retainer covers, and the protrusion is formed between the pair of slits. With this structure, by forming the protrusion between the slits, the protrusion can be lowered through the slits, and elasticity can be imparted to the protruding direction of the protrusion with a simple structure.

[0042] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the protrusion is formed at the center of the pair of slits in the longitudinal direction. With this structure, the elastic deformation amount of the protrusion using the slits can be increased.

[0043] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the thickness of the leaf spring portion sandwiched by the pair of slits is formed to be thinner than the thickness of the holder cover portion. This configuration imparts a layer of elasticity to the leaf spring portion having the protrusion.

[0044] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, each of the one or more secondary battery cells is formed in a cylindrical shape.

[0045] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, a plurality of the protrusions are provided on any one of the pair of holder cover portions.

[0046] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the plurality of protrusions are provided rotationally symmetrically in a circular shape of an end surface of the cylindrical secondary battery cell.

[0047] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the pair of slits are formed in an arc shape along the circumferential direction of the end surface of the cylindrical secondary battery cell.

[0048] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the protrusion is configured to press the negative electrode side end surfaces of each of the one or more secondary battery cells.

[0049] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples for concretizing the technical ideas of the present invention, and the present invention is not limited to the following. In addition, this specification does not limit the components shown in the claims to the components of the embodiments. In particular, the dimensions, materials, shapes, relative configurations, etc. of the structural components described in the embodiments, as long as there is no definite description, are not intended to limit the scope of the present invention to only these, but are simply illustrative examples. In addition, for the sake of clarity, the sizes, positional relationships, etc. of the components shown in the drawings are sometimes exaggerated. Furthermore, in the following description, the same names and symbols represent the same or homogeneous components, and detailed descriptions are appropriately omitted. Furthermore, the various elements constituting the present invention can be a method in which the same component constitutes multiple elements so that one component serves as multiple elements. Conversely, it can also be realized by having multiple components share the function of one component.

[0050] The battery pack of the present invention can be used as a driving power source for power-assisted bicycles, electric scooters for delivery, electric carts for golf courses, factories, airports, etc., a power source for self-propelled delivery robots, and a driving power source for vehicles such as construction machinery, hybrid vehicles, and electric vehicles. In addition, it can also be used as a power source for portable electrical equipment such as wireless devices, electric cleaners, and electric tools. Alternatively, it can be used as a backup power source for servers, or as a power supply device for use in homes, offices, and factories in a stationary storage capacity. Below, as one embodiment of the present invention, a battery pack used as a driving power source for power-assisted bicycles is described.

[0051] [Implementation Method 1]

[0052] The battery pack 100 according to the first embodiment of the present invention is shown in FIG. Figures 1 to 9 The battery pack 100 shown in these figures includes one or more secondary battery cells 1 and a battery holder 2 for holding the one or more secondary battery cells 1. Figure 1 、 Figure 2 As shown, the battery holder 2 is formed by stacking cylindrical bodies that are elongated along the outer shape of the secondary battery cells 1. Alternatively, an outer casing or the like that covers the outer periphery of the battery holder 2 may be added.

[0053] (Secondary battery cell 1)

[0054] Each secondary battery cell 1 is elongated in one direction and has a pair of end faces intersecting the elongated direction. Such a secondary battery cell 1 can be used with a square or cylindrical outer can. Figure 3 、 Figure 4 In the example shown, four cylindrical secondary battery cells 1 are stacked in two layers. In this example, the positive and negative electrodes of all the secondary battery cells 1 are aligned in the same direction. These secondary battery cells 1 are connected in series and in parallel via lead plates 30. Figure 3 、 Figure 4 In the example, four are connected in parallel, but two can be connected in series and two in parallel by dividing the lead plate 30. The number or arrangement of the secondary battery cells, the number of series or parallel connections, etc. are not limited to this example, and any number or arrangement can be appropriately adopted.

[0055] Each secondary battery cell 1 has positive and negative electrodes. The positive and negative electrodes are preferably provided on one end surface of the secondary battery cell 1. As such secondary battery cells 1, known secondary batteries such as lithium-ion secondary batteries, nickel-hydrogen batteries, and nickel-cadmium batteries can be appropriately used.

[0056] (Lead plate 30)

[0057] A lead plate 30 is arranged on the side of the battery holder 2. The lead plate 30 connects the electrodes on the end faces of the secondary battery cells 1 to each other, and connects multiple secondary battery cells 1 in series or in parallel. These lead plates 30 are made of metal plates with excellent conductivity, such as nickel plates. In addition, insulating plates can be arranged on the end faces of the lead plates 30 as needed. The insulating plates are made of materials with excellent insulating properties, such as paper and mica. Furthermore, a circuit substrate on which the protection circuit and charge and discharge circuit of the secondary battery cells are installed can be added to the battery pack as needed.

[0058] (Battery holder 2)

[0059] The battery holder 2 holds one or more secondary battery cells 1. Figure 5 、 Figure 6 As shown in the cross-sectional view of FIG, the battery holder 2 includes a hollow holder tube 3 that individually accommodates each secondary battery cell 1, and a pair of holder covers 12 and 22 that respectively block the hollow end faces of the holder tube 3. The holder tube 3 and the holder covers 12 and 22 form a cell storage space 4 for accommodating the secondary battery cell 1. Figure 6 As shown in FIG. 1 , each unit storage space 4 is divided separately. Figures 1 to 4 In the example of , in order to form a cell accommodating space 4 for accommodating four secondary battery cells 1, four retainer tubes 3 are stacked in a matrix of 2 rows x 2 columns. In order to prevent adjacent secondary battery cells 1 from contacting each other, as shown in FIG. Figure 5 、 Figure 6 As shown, each cell housing space 4 is individually partitioned within the holder tube 3 by partition walls 13 and 23. Meanwhile, adjacent holder tubes 3 are integrally formed on the outer surface of the holder tube 3. This battery holder 2 can be made of a material with excellent insulating properties, such as thermoplastic resins such as m-PPE (modified polyphenylene ether), ABS resin, PC (polycarbonate), PP (polypropylene), and PBT (polybutylene terephthalate), or thermosetting resins such as silicone resin, unsaturated phenolic resin, and unsaturated polyester.

[0060] In addition, each retainer cover 12, 22 has a window 18, 28 for connecting the electrodes on the end faces of the secondary battery cells 1 to the lead plates 30. The lead plates 30 are partially bent and protruded at locations corresponding to the windows 18, 28, so that electrical connection is established between the end faces of the secondary battery cells 1 and the retainer covers 12, 22 through the windows 18, 28.

[0061] (First retaining member 10; second retaining member 20)

[0062] The battery holder 2 is composed of a first holder 10 and a second holder 20 that are divided in the longitudinal direction of the secondary battery cell 1. The secondary battery cell 1 is held by being sandwiched between the first holder 10 and the second holder 20. With this structure, the protrusion 15, described later, can contact and hold the end face of the secondary battery cell 1 from the longitudinal direction.

[0063] The first retainer 10 and the second retainer 20 are composed of split retainer tubes 11 and 21, each of which is about 1 / 2 the length of the secondary battery cell 1, and retainer covers 12 and 22 that block one end face of the split retainer tubes 11 and 21, so that the retainer tube portion 3 is divided in the center of the longitudinal direction of the secondary battery cell 1. In addition, the other end face of the split retainer tubes 11 and 21 is set as an open end for inserting the secondary battery cell 1, and on the other hand, plate-shaped connecting walls 14 and 24 are provided around the open end. The connecting walls 14 and 24 connect the multiple split retainer tubes 11 and 21 at the end face, and as shown in FIG. Figure 3 、 Figure 4 As shown, it also functions as a joint surface for joining the first retainer 10 and the second retainer 20. In this example, the first retainer 10 and the second retainer 20 are joined by screws. The joint walls 14 and 24 have screw holes in the gaps between the secondary battery cells 1 stacked in a matrix. Figure 3 In the example shown, screw holes are provided in a cross-shaped pattern at five locations. The location and number of screw holes are not limited to this example and can be adjusted appropriately based on the number of secondary battery cells 1 housed in the battery holder 2, their layout, the required strength, and other factors. Furthermore, the coupling structure between the first holder 10 and the second holder 20 is not limited to a screw connection and may also be a claw-fitting structure.

[0064] (Protrusion 15)

[0065] In addition, at least one of the pair of retainer covers 12 and 22 has a protrusion 15. The protrusion 15 is provided on a portion of the retainer covers 12 and 22 so as to protrude toward the end face of the secondary battery cell 1 accommodated in the retainer tube 3. In addition, the protrusion 15 is provided so as to be elastically deformable in a direction protruding toward the end face of the secondary battery cell 1. Figure 5 、 Figure 6 In the example shown in FIG, the protrusion 15 is provided on the holder cover 12 of the first holder 10, while the protrusion is not provided on the holder cover 22 of the second holder 20. However, the present invention is not limited to this structure, and the protrusion may be provided only on the second holder, or on both the first holder and the second holder.

[0066] The cell accommodation space is designed to be large enough to accommodate a secondary battery cell. Figure 7 As shown in the cross-sectional view of the battery holder 902, the length Dh of the cell storage space 904 in the longitudinal direction is designed to be slightly larger than the length Dc of the secondary battery cell 901. As a result, a gap Dg is generated between the inner surface of the cell storage space 904 and the secondary battery cell 901, which may cause shaking. Therefore, a structure has been used in the past to fill the gap by clamping an elastic body such as silicone rubber and fastening it. However, this method not only requires additional components such as elastic parts, but also increases the number of man-hours in the manufacturing process due to the positioning and fixing of these additional components.

[0067] In contrast, in the battery pack 100 according to this embodiment, a protrusion 15 is provided on the inner surface of the cell housing space 4. By providing the protrusion 15 with an elastically deformable mechanism, the protrusion 15 protruding toward the end surface of the secondary battery cell 1 can be brought into contact with the end surface of the secondary battery cell 1 to fill the gap and maintain the cell. Specifically, Figure 5 As shown in the cross-sectional view, a protrusion 15 having a thickness of Dp is provided on the inner surface of the retainer cover 12 relative to the length Dh1 of the cell accommodating space 4 in the long side direction designed in consideration of manufacturing tolerances, etc. As a result, the length Dh2 of the cell accommodating space 4 at the position where the protrusion 15 is provided can be made smaller than the length Dh1 of the cell accommodating space 4 where no protrusion is provided. The thickness Dp of the protrusion 15 is set to the maximum value that can be assumed due to manufacturing tolerances, and is here set to a value greater than the difference between the maximum value of the length Dh1 of the cell accommodating space 4 and the minimum value of the length Dc of the secondary battery cell 1. As a result, when Figure 8 The secondary battery cell 1 is inserted into the first holder 10 and the second holder 20 as shown, and Figure 9 When the first retainer 10 and the second retainer 20 are connected, even if a gap Dg is generated between the inner surface of the cell accommodating space 4 and the secondary battery cell 1, the protrusion 15 elastically deforms and presses the end surface of the secondary battery cell 1 (at Figure 9 Therefore, the secondary battery cell 1 can be held in the cell accommodation space 4 without shaking.

[0068] The protrusion 15 preferably presses the flat side of the end face of the secondary battery cell 1. This is because the flat end face is easy to press. Generally, the negative end face of the secondary battery cell is flat, so the protrusion 15 is preferably provided on the inner surface of the retainer cover facing the negative end face. Figure 3 、 Figure 6 In the example of , the protrusion 15 is provided only on the holder cover 12 of the first holder 10 facing the negative electrode side. (Elastic structure)

[0069] In addition, the protrusion 15 has an elastic structure and is elastically deformed. By elastically deforming the protrusion 15, the gap between the cell accommodating space 4 and the secondary battery cell 1 in the longitudinal direction can be absorbed. Figures 10 to 12 As shown in FIG. 1 , a pair of slits 16 are formed in the holder cover portion 12 of the first holder 10, and a protrusion 15 is formed on the leaf spring portion 17 sandwiched by the pair of slits 16, thereby making the protrusion 15 elastic. That is, by forming the protrusion 15 on the leaf spring portion 17, as shown in FIG. Figure 8 、 Figure 9 As shown, the leaf spring portion 17 provided with the protrusion 15 is sunken by the slits 16 on both sides of the leaf spring portion 17. Thus, by providing the slits 16 in the resin holder cover portion, a simple structure can be used to give elasticity to the protruding direction of the protrusion 15.

[0070] like Figure 5 、 Figure 12 As shown in FIG. 1 and FIG. 2 , the leaf spring portion 17 is preferably formed to have a thickness Ds thinner than the thickness D1 of another region of the holder cover 12. By making the holder cover 12 partially thin, the leaf spring portion 17 can be easily elastically deformed. Figure 5 、 Figure 8 As shown in the enlarged cross-sectional view, a thin-walled leaf spring portion 17 is formed by providing a step from the outer surface of the retainer cover 12. Conversely, the inner surface of the retainer cover 12, where it contacts the secondary battery cell 1, is made flush with the surface. This allows for a thinner portion to be formed while avoiding a situation where the protrusion amount Dp of the protrusion 15 is reduced.

[0071] Such leaf spring portion 17 and protrusion 15 can be formed integrally with holder cover 12. Thus, without preparing a separate component, protrusion 15 having an inexpensive elastic structure can be added, thereby adding a function of stably holding secondary battery cell 1 regardless of the gap between secondary battery cell 1 and cell storage space 4.

[0072] The protrusion 15 is formed at the center of the pair of slits 16 in the longitudinal direction. This increases the elastic deformation of the protrusion 15 using the slits 16. Furthermore, the front end of the protrusion 15 is preferably flat. This allows a larger area to press against the end face of the secondary battery cell 1.

[0073] It is preferable to provide a plurality of protrusions 15. Figure 10 、 Figure 11 In the example shown, protrusions 15 are provided at three locations along the circumference of the circular holder cover 12. Each protrusion 15 is evenly spaced and offset 120° from the center of the circular shape of the holder cover 12. In this manner, the plurality of protrusions 15 are preferably provided rotationally symmetrically with respect to the circular shape of the holder cover 12.

[0074] [Implementation Methods 2 and 3]

[0075] On the other hand, protrusions 15 are provided at three different locations on the plane, and each protrusion 15 presses the end face of the secondary battery cell 1, thereby being able to contact the end face of the secondary battery cell 1 at each location, and stably press and hold the secondary battery cell 1. However, the location and number of the protrusions are not limited to this structure, and any number and arrangement can be used. For example, Figure 13 As in the case of the inner surface of the holder cover 12B of the battery pack according to the second embodiment shown in FIG. 1 , the protrusions 15B may be provided at two locations, or as in the case of Figure 14 As shown in the figure, the protrusions 15C are provided at four locations, as on the inner surface of the retaining cover 12C of the battery pack involved in the third embodiment. When the protrusions are provided at four or more locations, non-contacting protrusions may be generated depending on the angles between the end faces of the secondary battery cells and the inner surface of the retaining cover. Therefore, from the viewpoint of efficiently retaining secondary battery cells with a smaller number, it can be said that it is preferable to provide the protrusions at three or less. In addition, in the case where the protrusion is provided at one, it is preferably provided at the center of the circle of the retaining cover. In addition, in the figures showing the various embodiments, the same symbols are given to the same components as those of the battery pack involved in the above-mentioned first embodiment, and detailed descriptions are omitted as appropriate. In addition, after the second embodiment, the illustration of the window opening in the retaining cover is omitted for explanation.

[0076] [Implementation 4]

[0077] Furthermore, in the above example, the arc-shaped slit is provided at a position separated from the outer periphery of the holder cover, but it is not limited to such a configuration. For example, Figure 15 As in the inner surface of the holder cover 12D of the battery pack according to the fourth embodiment shown, a slit 16D is formed along the outer periphery of the holder cover 12D.

[0078] [Implementation Methods 5 and 6]

[0079] On the other hand, regarding the pattern of the slits 16 forming the elastic structure, in addition to the Figure 10 、 Figure 11 In addition to being formed into an arc shape along the circle of the holder cover portion 12 as shown in FIG, it can also be formed into a straight line. Figure 16 In the embodiment 5 shown, the inner surface of the battery pack holder cover 12E is formed with a pair of slits 16E in parallel straight lines. In addition, the direction of the slits is not limited to the direction along the arc or the line of the circle. Figure 17In the battery pack according to the sixth embodiment, a pair of slits 16F are formed on the inner surface of the holder cover 12F so as to extend in the radial direction of the circle. Figure 17 In the example of FIG, three protrusions 15F are formed, but two protrusions may be provided in a straight line along the diameter of the circle. By making the slits straight in this way, the advantage of easy formation is obtained. On the other hand, by Figure 10 Forming the slit 16 along the arc direction as shown in the figure allows the leaf spring portion 17 to be formed along the shape of the holder cover 12 , thereby preventing stress concentration from occurring around the slit 16 , which is preferable in terms of maintaining the strength of the holder cover 12 .

[0080] [Embodiments 7 and 8]

[0081] On the other hand, in the above example, a structure in which a pair of slits 16 are formed and a leaf spring portion 17 is formed between the slits 16 has been described, but the elastic structure is not limited to this structure. Figure 18 As shown in the embodiment 7, the inner surface of the battery pack holder cover 12G may be formed into a cantilever spring portion 17G with the slit 16G formed in a U shape. This can increase the displacement of the protrusion 15G due to elastic deformation. On the other hand, since the pressing force of the protrusion 15G is reduced, the thickness of the cantilever spring portion 17G may be increased as needed. In addition, when forming the cantilever spring portion 17G, in addition to the above Figure 18 In addition to forming the slit 16G into an arc shape, it is also possible to form the slit 16G into an arc shape. Figure 19 As in the inner surface of the holder cover 12H of the battery pack according to the eighth embodiment shown, the slit 16H is formed in a linear shape.

[0082] [Implementation Method 9]

[0083] In the above example, as the protrusion 15, Figure 8 As shown in the enlarged cross-sectional view of the main part, the block-shaped shape protruding from the plane of the leaf spring portion 17 is described. However, the present disclosure does not limit the protrusion to a shape protruding from the plane of the leaf spring portion. As long as the leaf spring portion itself protrudes, such a structure is also included in the name of the protrusion. Such an example is shown as a battery pack 100J according to the ninth embodiment. Figure 20sectional view. In this figure, the same reference numerals are given to the same components as those of the battery pack according to the first embodiment, and detailed descriptions are omitted. The battery pack 100J shown in this figure has a leaf spring portion 12J protruding from the inner surface of the retaining member cover portion 12J into a trapezoidal shape, thereby forming a protrusion 15J. The leaf spring portion 12J protruding in a trapezoidal shape abuts against the end face of the secondary battery cell 1 accommodated in the cell accommodating space 4J and elastically deforms, thereby holding the secondary battery cell 1 in a pressed state. By thus forming the protrusion 15J into a trapezoidal shape, the end face of the secondary battery cell 1 can be pressed and stably held over a larger area. The structure in which such a leaf spring portion 12J itself is deformed to form the protrusion 15J can be easily formed on the retaining member cover portion 12J by integral molding.

[0084] [Implementation 10]

[0085] Furthermore, in the above example, the secondary battery cells 1 accommodated in the cell accommodating space 4 of the battery holder 2 are held in a posture in which the same electrodes are aligned with each other on the same surface. In this structure, as long as any one of the split holders constituting the battery holder 2 is aligned with the same surface, Figure 10 In the example shown in FIG. 1 , it is sufficient to provide the protrusion 15 only on the first retainer 10. On the other hand, there is also a case where a plurality of secondary battery cells are stacked in a battery retainer with the positive and negative electrodes facing in different directions. In such a case, it is desirable to form protrusions on the first retainer and the second retainer, respectively. For example, as the battery pack involved in embodiment 10, in Figure 21 Stereoscopic images and Figure 22 In the battery pack 100I shown in the exploded perspective view, a plurality of secondary battery cells 1 are stacked in a state where the positive and negative electrodes face different directions and are held by a first holder 10I and a second holder 20I. Figure 23 shown Figure 22 A front view of the second retaining member 20I, and Figure 24 As shown, viewed from the back Figure 22 As shown in the front view of the first retainer 10I, in the corresponding cell accommodating spaces of the first and second retainers 10I, protrusions 15I are provided on the inner surface of the retainer cover 12I, 22I of one of the split retainers, while no protrusions are provided on the retainer cover 12I, 22I of the other split retainer. In this way, by providing protrusions on either of the retainer covers 12I, 22I that define the corresponding cell accommodating spaces in each split retainer, even in a battery holder 2I in which secondary battery cells 1 are stacked in different directions, the gaps between the cell accommodating spaces and the secondary battery cells 1 in the longitudinal direction can be filled to prevent any shaking.

[0086] In the above example, the battery pack is assembled to the electrical device to be driven to supply power to the electrical device. In addition, when the remaining capacity of the battery pack is low or the battery pack has deteriorated over the years, the battery pack can be replaced and the electrical device can continue to be used. However, the present disclosure is not limited to a replaceable battery pack in which the battery pack mainly accommodates secondary battery cells, but can also be applied to a method in which secondary battery cells are accommodated in the frame of the electrical device. In the present disclosure, the battery pack only needs to accommodate secondary battery cells in the shell, and the structure in which the secondary battery cells for driving are built into the frame of the electrical device itself is also called a battery pack. That is, the present disclosure is not limited to replaceable battery packs, but can also be applied to electrical devices with built-in secondary battery cells.

[0087] Industrial applicability

[0088] The battery pack of the present invention can be suitably used as a driving power source for vehicles such as power-assisted bicycles, self-propelled delivery robots, delivery vehicles, electric carts for golf courses, electric scooters, construction machinery, hybrid vehicles, and electric vehicles. Furthermore, it can be suitably used as a power source for portable electrical equipment such as wireless radios, electric cleaners, and power tools, as a backup power source for servers in stationary storage applications, and as a power source for homes, offices, and factories.

[0089] -Explanation of Symbols-

[0090] 100, 100I, 100J…battery pack

[0091] 1…Secondary battery cell

[0092] 2…Battery holder

[0093] 3…Retainer tube

[0094] 4. 4J…single unit storage space

[0095] 10, 10I...first retaining member

[0096] 11… Split retainer tube

[0097] 12, 12B, 12C, 12D, 12E, 12F, 12G, 12H, 12I, 12J…Retainer cover

[0098] 13…Separation wall

[0099] 14…Joint wall

[0100] 15, 15F, 15G, 15I, 15J…protrusions

[0101] 16, 16D, 16E, 16F, 16G, 16H…slit

[0102] 17, 17J…Leaf spring; 17G…Cantilever spring

[0103] 18…Window

[0104] 20, 20I…second retaining member

[0105] 21… Split retainer tube

[0106] 22…Retainer cover

[0107] 23…Separation wall

[0108] 24…Joint wall

[0109] 28…Window

[0110] 30...lead board

[0111] 901…Secondary battery cell

[0112] 902…Battery holder

[0113] 904…single storage space

[0114] Dh, Dh1…length of the single unit storage space

[0115] Dh2: Length of the cell storage space at the position where the protrusion is provided

[0116] Dc...length of the secondary battery cell

[0117] Dg…Gap between the inner surface of the cell housing space and the secondary battery cell

[0118] D1...Thickness of the holder cover

[0119] Ds…Thickness of leaf spring

[0120] Dp...thickness of the protrusion.

Claims

1. A battery pack comprising: One or more secondary battery cells, each extending in one direction and having a pair of end faces intersecting the extending direction; and a battery holder for holding the one or more secondary battery cells; The battery holder comprises: a hollow holder cylindrical portion for individually accommodating the one or more secondary battery cells; and A pair of retainer cover parts respectively block the hollow end surfaces of the retainer tube part. At least one of the pair of holder cover portions includes an elastically deformable protrusion portion, the protrusion portion partially protruding toward one of a pair of end surfaces of the secondary battery cell accommodated in the holder tube portion. The battery holder is formed by combining a first holder and a second holder that are at least divided into two in the longitudinal direction of the one or more secondary battery cells. The protrusion is configured to press end surfaces of the one or more secondary battery cells when the first retainer and the second retainer are coupled together.

2. The battery pack according to claim 1, wherein: The battery holder is formed so that a cell accommodating space formed by the holder tube portion and the pair of holder covers for individually accommodating the one or more secondary battery cells is formed such that a distance between the pair of holder covers along the length of each secondary battery cell is longer than the length of each of the one or more secondary battery cells, and The length of the cell accommodating space along the longitudinal direction of each secondary battery cell, which is defined by the front end of the protrusion, is shorter than the length of each of the one or more secondary battery cells.

3. The battery pack according to claim 1, wherein: The protrusion is integrally formed with any one of the pair of holder covers.

4. The battery pack according to claim 3, wherein: A pair of slits is formed in either of the pair of holder covers, The protrusion is formed between the pair of slits.

5. The battery pack according to claim 4, wherein: The protrusion is formed at the center of the pair of slits in the longitudinal direction.

6. The battery pack according to claim 4, wherein: The thickness of the leaf spring portion sandwiched between the pair of slits is formed to be thinner than the thickness of the holder cover portion.

7. The battery pack according to claim 4, wherein: The one or more secondary battery cells are each formed in a cylindrical shape.

8. The battery pack according to claim 7, wherein: A plurality of the protrusions are provided on any one of the pair of holder covers.

9. The battery pack according to claim 8, wherein: The plurality of protrusions are provided rotationally symmetrically in a circular shape of an end surface of the cylindrical secondary battery cell.

10. The battery pack according to claim 8, wherein: The pair of slits are formed in an arc shape along the circumferential direction of the end surface of the cylindrical secondary battery cell.

11. The battery pack according to any one of claims 1 to 10, wherein: The protrusion is configured to press the negative electrode side end surfaces of the one or more secondary battery cells.

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