JP2012059373A - Battery pack and battery holder for battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate metal molding of a battery holder.SOLUTION: A first divided holder 22A and a second divided holder 22B formed by dividing the battery holder into two respectively have first divided storage spaces 28A and second divided storage spaces 28B sectioned to store parts of battery cells 26. The first divided holder 22A has a first cut area 24 formed by cutting a part of a storage wall 29 determining the first divided storage spaces 28A in a region in which the first divided storage spaces 28A are adjacent to each other with spaces therebetween, and the second divided holder 22B has a second cut area 25 formed by cutting a part of a storage wall 29 determining the second divided storage spaces 28B in a region in which the second divided storage spaces 28B are adjacent to each other with spaces therebetween. The first cut area 24 and the second cut area 25 are provided at positions apart from each other so that they are not sequentially arranged.

Description

  The present invention relates to a battery pack including a plurality of rechargeable secondary batteries and a battery holder for the battery pack.

  A battery pack using a secondary battery is used as a drive source for an electric device such as an assist bicycle. Such a battery pack uses a battery holder to hold a plurality of secondary batteries in a fixed posture. Such a battery holder is generally made of resin and is formed by molding. The mold is generally divided into left and right parts with respect to the longitudinal direction of the storage wall for storing the battery cells, and is composed of a cavity and a core. In order to mold the storage wall, it is necessary to form a slight gradient, so-called draft angle, in the cavity and the core.

  However, when the number of battery cells stored in one battery holder increases, the resistance to punching at the time of mold molding increases, and it becomes difficult to remove the mold. In particular, in order to respond to the recent demands for large capacity and space, a storage space for storing a large number of battery cells in a single battery holder if a plurality of battery cells are held in parallel. Need to be formed. As the storage space in the battery holder increases, the resistance when the mold is removed increases, and in some cases, the battery holder may be deformed or the battery holder or the mold may be damaged. In other words, when a thick part occurs in resin molding or the like, so-called meat stealing or meat, in which a concave part is intentionally formed to equalize the thick part in order to reduce sink marks when the resin is cured. Unplugging has been done. Generally, it is attempted to reduce the wall thickness by adding a pin or the like to a mold corresponding to the meat lump portion. However, in this case, the cost of the mold increases due to the molding of the pins. Moreover, when the pin becomes longer, the mold strength becomes weaker. In addition, the punching resistance at the time of molding increases, and the moldability is inferior. Further, if the pin is a cylindrical round pin, it is difficult to achieve a completely uniform wall thickness, and there has been a problem that the mold cost will become higher if this is made constant.

JP 200431284 A

  The present invention has been made to solve such conventional problems. A main object of the present invention is to provide a battery pack and a battery holder for a battery pack that can easily mold a battery holder.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, according to the battery pack of the first aspect of the present invention, a plurality of battery cells 26 having an outer shape extended in one direction and the plurality of battery cells 26 are individually provided. A battery pack including a plurality of battery holders 22 and 122 each having a storage space 28 to be stored adjacent to each other, wherein the battery holders 22 and 122 are first in the longitudinal direction of the battery cell 26. The first divided holder 22A and the second divided holder 22B are divided into a divided holder 22A and a second divided holder 22B. Each of the first divided holder 22A and the second divided holder 22B accommodates a part of the battery cell 26. The second divided storage space 28B is defined, and the first divided storage space 28A and the second divided storage space 28B are joined by joining the first divided holder 22A and the second divided holder 22B. Are connected on a substantially concentric shaft to define the storage space, and the first divided holder 22A is configured to define the first divided storage space 28A in a region adjacent to the first divided storage space 28A. A first cutout region 24 is formed by cutting out a part of the storage wall 29 to be defined, and the second divided holder 22B is formed in a region adjacent to the second divided storage space 28B. A second cutout region 25 is formed by cutting out a part of the storage wall 29 that defines the second divided storage space 28B so that the first cutout region 24 and the second cutout region 25 are not continuous. , And can be provided at a position where they are separated from each other. Thereby, by partially notching the storage wall of the battery holder, it is possible to reduce the resistance to punching when the battery holder is molded, while preventing the notch region from being continuous between the first split holder and the second split holder. By disposing, it is possible to suppress and disperse a decrease in the heat dissipation performance of the battery cell, and to avoid a decrease in the protection capability of the battery cell.

  In the battery pack according to the second aspect, the first cutout region 24 or the second cutout region 25 is partially in the longitudinal direction of the first divided storage space 28A and the second divided storage space 28B. Can be formed. Accordingly, the first cutout area and the second cutout area are not provided with the first cutout area and the second cutout area in the entire longitudinal direction of the first divided storage space, and in other words, such a cutout area is not provided. By leaving a region in contact with the surface over the entire circumference of the battery, there is an advantage that heat conduction from the surface of the battery cell is maintained and deterioration of heat dissipation can be suppressed.

  Further, according to the battery pack of the third aspect, the first cutout region 24 or the second cutout region 25 is about 1 of the length of the first divided storage space 28A or the second divided storage space 28B. / 3 to 1/2 can be provided. As a result, the first cutout region is provided only in a part of the first divided storage space, and it is possible to achieve both maintenance of the heat dissipation performance of the battery cell and reduction of the pulling resistance when the mold is removed. .

  Furthermore, according to the battery pack of the fourth aspect, the second notch region 25 is located from the position of the storage wall 29 corresponding to the position where the first notch region 24 of the first split holder 22A is provided. The battery cell 26 can be provided at a position separated in a direction substantially perpendicular to the longitudinal direction of the battery cell 26. Thereby, a 1st notch area | region and a 2nd notch area | region can be spatially separated, and the situation where the site | part to which heat dissipation declines concentrates can be avoided.

  Furthermore, according to the battery pack according to the fifth aspect, the second cutout area 25 is located from the position of the storage wall 29 corresponding to the position where the first cutout area 24 of the first split holder 22A is provided. The battery cells 26 can be provided at positions separated in the longitudinal direction. Thereby, a 1st notch area | region and a 2nd notch area | region can be spaced apart in a longitudinal direction, and the situation where the site | part to which heat dissipation declines concentrates can be avoided.

  Furthermore, according to the battery pack according to the sixth aspect, in the first divided holder 22A, the first cutout region 24 is arranged so as not to be continuous in the adjacent first divided storage space 28A. be able to. Thereby, since a 1st notch area | region does not continue in a horizontal direction, the area | region where the heat dissipation of a battery cell falls can be disperse | distributed.

  Furthermore, according to the battery pack which concerns on a 7th side surface, the distance of adjacent storage space can be varied at least in part. Thereby, when the battery cells are irregularly arranged in the battery holder and the distance between the adjacent battery cells is not constant, in other words, when the thickness of the storage wall defining the storage space is uneven, A so-called meat stealing structure can be effectively provided.

  Furthermore, according to the battery pack which concerns on an 8th side surface, the said storage space can be arrange | positioned at offset shape.

  Furthermore, according to the battery pack of the ninth aspect, the storage space can be arranged in a grid pattern.

  Furthermore, according to the battery holder of the tenth aspect, a battery holder in which a plurality of storage spaces for individually storing a plurality of battery cells 26 having an outer shape extended in one direction are defined so as to be adjacent to each other. 22 and 122, which are divided in the longitudinal direction of the battery cell 26 into a first divided holder 22A and a second divided holder 22B. The first divided holder 22A and the second divided holder 22B A first divided storage space 28A and a second divided storage space 28B for storing a part of the battery cell 26 are defined, and the first divided holder 22A and the second divided holder 22B are joined. Thus, the first divided storage space 28A and the second divided storage space 28B are connected on a substantially concentric shaft to define the storage space, and the first divided holder 22A is connected to the first divided storage space 28A. In a region adjacent to each other, a first cutout region 24 is formed by cutting out a part of the storage wall 29 that defines the first divided storage space 28A, and the second divided holder 22B On the joint surface with the first divided holder 22A, the storage wall 29 that defines the second divided storage space 28B at a position corresponding to the first cutout region 24 of the first divided holder 22A is not provided with a cutout. The second cutout region 25 in which a part of the storage wall 29 is cut out at another position can be provided. Thereby, by partially notching the storage wall of the battery holder, it is possible to reduce the resistance to punching when the battery holder is molded, while preventing the notch region from being continuous between the first split holder and the second split holder. By arrange | positioning in offset shape, the fall of the thermal radiation performance of a battery cell can be suppressed and disperse | distributed, and the fall of the protection capability of a battery cell can also be avoided.

It is a perspective view which shows the external appearance of a battery pack. It is a disassembled perspective view of the battery pack of FIG. FIG. 3 is an exploded perspective view of the core pack of FIG. 2. It is a disassembled perspective view which shows the state which removed the lead board from the core pack of FIG. It is a disassembled perspective view of the battery holder of FIG. It is a perspective view which shows the 1st division | segmentation holder of FIG. 5, and the 2nd division | segmentation holder joined to this. It is the perspective view which looked at the 1st division holder and the 2nd division holder of Drawing 6 from the back. It is a top view of the 1st division | segmentation holder of FIG. It is sectional drawing in the IX-IX line of the 1st division | segmentation holder of FIG. It is sectional drawing in the XX line of the 1st division | segmentation holder of FIG. It is a perspective view which shows the conventional battery holder. It is the perspective view which looked at the battery holder of FIG. 11 from the back. It is a top view of the battery holder of FIG. It is sectional drawing in the XIV-XIV line of the battery holder of FIG. It is sectional drawing in the XV-XV line | wire of the battery holder of FIG. It is a perspective view which shows the battery holder which this inventor developed previously. It is the perspective view which looked at the battery holder of FIG. 16 from the back surface. It is a perspective view which shows the joining area | region in the battery holder which this inventor developed previously. It is a schematic diagram which shows the joining area | region in the battery holder which this inventor developed previously. It is a schematic diagram which shows the part which provided the notch area | region. It is a perspective view which shows the 1st division | segmentation holder which concerns on a modification. It is the perspective view which looked at the 1st division holder of Drawing 21 from the back. It is a cross-sectional perspective view which shows the state which joined the 1st division | segmentation holder of FIG. 22 with the 2nd division | segmentation holder. It is an enlarged view which shows the 2nd division | segmentation holder of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a battery pack and a battery holder for the battery pack for embodying the technical idea of the present invention, and the present invention describes the battery pack and the battery holder for the battery pack as follows. Not specific to anything. In addition, the member shown by the claim is not what specifies the member of embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

1 to 19 show a battery pack 100 according to the first embodiment. In these drawings, FIG. 1 is a perspective view showing the appearance of the battery pack 100, FIG. 2 is an exploded perspective view of the battery pack 100 of FIG. 1, FIG. 3 is an exploded perspective view of the core pack 20 of FIG. 3 is an exploded perspective view showing a state in which the lead plate 40 is removed from the core pack 20 of FIG. 3, FIG. 5 is an exploded perspective view of the battery holder 22 of FIG. 4, and FIG. 6 is a first split holder 22A of FIG. 7 is a perspective view of the two-divided holder 22B, FIG. 7 is a perspective view of the first divided holder 22A and the second divided holder 22B in FIG. 6 as viewed from the back, and FIG. 8 is a plan view of the first divided holder 22A in FIG. 9 is a sectional view taken along line IX-IX of the first divided holder 22A in FIG. 8, FIG. 10 is a sectional view taken along line XX of the first divided holder 22A in FIG. 8, and FIG. The perspective view which shows the battery holder 92, FIG. 12 is the battery holder of FIG. FIG. 13 is a plan view of the battery holder 92 of FIG. 11, FIG. 14 is a cross-sectional view of the battery holder 92 of FIG. 13, taken along line XIV-XIV, and FIG. 15 is a perspective view of the battery holder 92 of FIG. FIG. 16 is a perspective view showing another battery holder 192 previously developed by the present inventor, FIG. 17 is a perspective view of the battery holder 192 of FIG. 16 viewed from the back, and FIG. The perspective view which shows the joining area | region in the battery holder 192 which the inventor developed previously, FIG. 19 has shown the schematic diagram which shows the joining area | region in the battery holder 192 which this inventor developed previously, respectively. The battery pack 100 shown in these drawings illustrates a battery pack for an electrically assisted bicycle. For this reason, the battery pack 100 is configured such that the outer case 10 constituting the outer shape is formed in a square shape and can be set on the loading platform portion of the bicycle. The rectangular outer case 10 is formed thin so that the thickness is smaller than the width.
(Outer case 10)

As shown in FIGS. 1 to 2, the battery pack 100 opens both end surfaces of the rectangular outer case 10 so that the core pack 20 can be inserted, and each end surface is closed by the end plate 14. The outer case 10 is made of metal such as aluminum having excellent strength and heat dissipation. The end face plate 14 is formed in the same rectangular shape as the opening so as to close the opening end of the outer case 10. Further, the material is made of a metal excellent in durability and heat dissipation as in the case 10. This end face plate 14 is fixed to the outer case 10 by screwing four corners. Further, an output terminal connector 16 is provided on one end plate 14 (the left end plate 14A in FIGS. 1 and 2).
(Core pack 20)

The core pack 20 is configured by laminating a plurality of battery blocks 21 in the length direction, as shown in FIGS. In the example of these drawings, the core pack 20 is configured by stacking two battery blocks 21 in the length direction of the battery cells 26. A substrate holder 31 for holding the circuit board 30 is provided on the upper surface of the core pack 20 as shown in FIGS. In particular, the core pack 20 is formed by stacking the battery cells 26 in two stages and providing an intermediate region having only one battery cell 26 in the middle, thereby providing a step on the upper surface and utilizing the space generated by the step. The circuit board 30 is arranged. With this configuration, it is not necessary to separately prepare a space for storing the circuit board 30, and the battery pack can be prevented from being thickened. In addition, the circuit board 30 is not placed on the upper surface of the core pack as it is, but the left and right battery cells 26 are projected in two stages, so that the left and right sides of the circuit board 30 are protected by the battery cells 26. It is also preferable from the viewpoint that the circuit board 30 can be stably placed and protected.
(Circuit board 30)

The circuit board 30 accommodated in the board holder 31 is formed in a rectangular shape extending along the stacking direction of the core pack 20, that is, along the longitudinal direction of the battery cell 26. In addition, an electronic circuit such as a protection circuit for the battery cell 26 is mounted on the circuit board 30. The protection circuit protects the battery cell 26 by preventing overcharge and overdischarge of the battery cell 26. For this reason, the circuit board 30 is electrically connected to the lead plate 40 of each battery block 21 in order to detect the voltage (cell voltage) of each battery cell 26. A temperature sensor for detecting the temperature of the battery cell 26 (cell temperature) is also connected. The temperature sensor is in contact with the surface of the battery cell, or in contact with the battery cell through a heat conductive material, or is thermally coupled to the battery cell by approaching the surface of the battery cell to detect the battery temperature. As the temperature sensor, a thermistor, PTC, varistor, or the like can be used, and an element that can detect the temperature in a non-contact state by detecting infrared rays emitted from the battery cell can be used.
(Battery block 21)

  As shown in the exploded perspective views of FIGS. 3 and 4, each battery block 21 has a battery cell 26 inserted into the storage space 28 of the battery holder 22 and a lead plate 40 fixed to the end surface. The battery holder 22 is divided into two divided holders, ie, a first divided holder 22A (left side in FIG. 5) and a second divided holder 22B (right side in FIG. 5), and the battery cell 26 is sandwiched from both sides. Hold. Preferably, the dividing position is approximately the center of the battery holder 22 in the longitudinal direction of the battery cell 26. Accordingly, the battery cell 26 can be stored in the storage space 28 and held so as to be sandwiched from the left and right by the battery holder 22 divided into two. A holding member 27 is provided on the end face side of the storage space 28. The holding member 27 is a member for holding the battery cell 26 stored in the storage space 28 so as not to fall off. Thus, each battery cell 26 can be stored in the storage space 28 by being sandwiched from both sides by the first split holder 22A and the second split holder 22B, and the battery cell 26 can be inserted into the storage space 28 while being stored. Can be prevented by the holding member 27.

As described above, each battery block 21 has a storage space 28 in which battery cells 26 are individually stored. These storage spaces 28 define the opening direction of the storage space 28 so that when the battery cells 26 are stored, the extending direction of the battery cells 26 matches the opening direction of the battery block 21. . Further, the length of each of the divided holders constituting the battery block 21 is set so that the battery cell 26 can be stored in the storage space 28 configured by combining the first divided holder 22A and the second divided holder 22B. About half of the length.
(Battery holder 22)

  As described above, each battery holder 22 stores a plurality of battery cells 26 in a parallel posture. In this example, the core pack 20 is configured by connecting two battery holders 22 that store eight battery cells 26 in a parallel posture. Each battery holder 22 defines a storage space for storing the battery cells 26 as shown in FIG. Each battery holder 22 exposes the end face electrode 26b of the battery cell 26 from the end face, and the lead plate 40 is fixed to this part. The lead plate 40 connects the battery cells 26 in series and / or in parallel. In this example, in each battery holder 22, battery cells 26 are connected in two lines and four lines.

In addition, this example is an example and it cannot be overemphasized that arbitrary forms can be utilized about the number of battery cells used, arrangement | positioning form, etc. FIG. For example, the battery cells arranged on the upper surface may have an offset arrangement in which the lower surface and the center position are eccentric. Each divided holder is preferably formed by integral molding. For example, it is made of resin such as polypropylene having excellent insulating properties. Further, the divided holders are fixed by a method such as screwing.
(Battery cell 26)

The battery cell 26 uses a columnar or cylindrical battery cell 26 extending in one direction. As the battery cell 26, a secondary battery such as a lithium ion secondary battery, a nickel hydride battery, or a nickel cadmium battery can be suitably used. The size of the battery cell 26 is preferably a standardized size such as 18650 type (cylindrical shape having a diameter of 18 mm and a height of 65 mm) or 17670 type. Moreover, it can also be set as a commercially available AA battery, a AAA battery, etc. In this example, a cylindrical battery is used, but it goes without saying that a rectangular battery may be used.
(Lead plate 40)

  As shown in FIG. 4, the end surface electrodes 26 b on both sides of the battery cell 26 are exposed at the open end opened at the end surface of the battery holder 22, and the end surfaces of the adjacent battery cells 26 are fixed to the lead plate 40 in this state. Is conducted. The lead plate 40 is made of a metal plate and is fixed to the end face electrode 26b of the battery cell 26 by spot welding or the like. The lead plate 40 has a plurality of battery cells 26 fixed to one lead plate 40 in order to further connect the battery cells 26 connected in parallel. In the example of FIG. 4, in order to connect the four battery cells 26 in parallel, eight battery cells 26 are fixed to one lead plate 40 disposed on both end faces. In addition, the lead plate 40 between the battery blocks 21 uses a lead plate 40 </ b> B which is connected and folded by connecting four battery cells 26, and a lead plate 40 </ b> C which is connected to each of the four battery cells 26.

In order to hold each lead plate 40 in a fixed position, the battery holder 22 forms a guide portion along the outer periphery of the lead plate 40 so that the lead plate 40 is disposed inside. Preferably, the guide portion can also be used as the holding member 27 provided at the opening end of the storage space 28, thereby realizing the positioning of the lead plate 40 and the holding of the battery cell 26.
(First division holder 22A)

  Each battery holder 22 is divided into a plurality. In the example shown in the exploded perspective view of FIG. 5, the battery cell 26 is divided into a first divided holder 22 </ b> A and a second divided holder 22 </ b> B in the longitudinal direction. A storage space is defined by joining the first split holder 22A and the second split holder 22B so as to sandwich the battery cell 26 from the left and right, and the battery cell 26 is stored in each storage space. Therefore, a first divided storage space 28A and a second divided storage space 28B are defined in the first divided holder 22A and the second divided holder 22B, respectively, and the first divided holder 22A and the second divided holder 22B are defined. , The first divided storage space 28A and the second divided storage space 28B are connected on a substantially concentric shaft to define a storage space. 22 A of 1st division holders and the 2nd division holder 22B are comprised with the member excellent in insulation, respectively, and are made from resin here. The resin first divided holder 22A and the second divided holder 22B are each injection-molded by a mold. In this example, the first divided holder 22A and the second divided holder 22B are configured in different shapes, but can be shared as the same shape.

As shown in the perspective views of FIGS. 6 and 7, the first divided holder 22A is formed in a shape in which the first divided storage spaces 28A are connected in parallel to each other. The first divided storage space 28A has an inner diameter that is substantially the same as or slightly larger than the outer shape of the battery cell 26, so that the battery cell 26 can be inserted therein. The length of the first divided storage space 28 </ b> A is formed to be approximately half the length of the battery cell 26 in the longitudinal direction. Similarly, the second divided holder 22B is formed in a substantially half length by matching the second divided storage space 28B with the outer shape of the battery cell 26.
(Joining means)

  Moreover, it is preferable to provide the joining surface which joins these division holders in the joining surface of 22 A of 1st division holders, and the 2nd division holder 22B. For example, a boss is formed on one of the joint surfaces, and a boss hole for inserting the boss is formed at a corresponding position on the other joint surface. By inserting the boss into the boss hole, the first divided holder 22A and the second divided holder 22B can be positioned and joined. However, it is not essential to provide the joining means, and the battery cell itself can be used as the positioning means. That is, by inserting battery cells into the first divided storage space 28A and the second divided storage space 28B, these storage spaces are positioned, and the first divided holder and the second divided holder are used with a plurality of battery cells as positioning guides. Can be joined.

In this way, the first divided holder 22A and the second divided holder 22B are joined, and the first divided storage space 28A and the second divided storage space 28B are connected on the concentric shaft to define the storage space. Is done. Furthermore, the battery cell 26 accommodated in this accommodation space makes a cylindrical outer can contact the accommodation wall 29 and is thermally coupled, and the heat generated by the battery cell 26 is transmitted to the battery holder 22 to facilitate heat dissipation.
(First cutout region 24)

  Further, the first cutout region 24 is partially formed in the first divided storage space 28A in the longitudinal direction. As shown in FIGS. 8 to 9, a part of the storage wall 29 that defines the first divided storage space 28 </ b> A is partially formed in an area where the first divided storage space 28 </ b> A is separated and adjacent to each other in the first divided holder 22 </ b> A. A first notch region 24 is formed here. On the other hand, in the second split holder 22B, as shown in the perspective views of FIGS. 6 and 7, at the position corresponding to the first notch region 24 of the first split holder 22A on the joint surface with the first split holder 22A. The storage wall 29 that defines the second divided storage space 28B is not provided with a notch. Instead, a second cutout region 25 in which a part of the storage wall 29 is partially cutout at another position is provided. In the example of the first divided holder 22A and the second divided holder 22B shown in FIG. 6 and FIG. 7, the first cutout region 24 at the lower right of the first divided storage space 28AA at the upper left in FIGS. Is provided. In this manner, by partially cutting away the storage wall 29 of the battery holder 22, it is possible to reduce the pulling resistance when the battery holder 22 is molded.

On the other hand, if the notched region is provided, contact between the battery cell outer can and the storage wall of the battery holder 22 is lost at that portion, and thus the heat dissipation is reduced accordingly. Therefore, it is preferable that the cutout region is not provided over the entire length of the divided storage space but is formed only in a part in the longitudinal direction. Accordingly, the first notch region 24 and the second notch region 25 are not provided in the entire longitudinal direction of the first divided storage space 28A and the second divided storage space 28B, and such a notch region is not provided. In other words, by leaving a region in contact with the surface over the entire circumference of the battery cell, there is an advantage that heat conduction from the surface of the battery cell is maintained and deterioration of heat dissipation can be suppressed. In the example of FIG. 6, as shown in the cross-sectional view of FIG. 10 and the rear right side of the perspective view of FIG. 7, the first notch region 24 is not provided on the back side of the upper left first divided storage space 28AA. In this way, by limiting the length of the cutout region, it is possible to minimize a decrease in the heat dissipation performance of the battery cell 26 stored in the first divided storage space 28AA located at the upper left of the first divided holder 22A. . The length of such a cutout region is preferably about 1/3 to 1/2 of the length of the divided storage space. Thereby, it is possible to provide the first cutout region 24 only in a part of the first divided storage space 28A, and to maintain both the heat dissipation performance of the battery cell and the reduction of the punching resistance when the mold is removed. It becomes.
(Second cutout area 25)

  Furthermore, it is preferable to provide the 2nd notch area | region 25 provided in 2nd division | segmentation holder 22B in the position which separated both so that it may not continue with the 1st notch area | region 24 of 22 A of 1st division | segmentation holders. That is, if the cutout region continues, it is considered that the region with poor heat dissipation is concentrated and the heat dissipation of the battery cell is affected, so that these heat dissipation can be achieved by separating and dispersing them. A decrease in performance can be suppressed.

  Specifically, the second cutout region 25 is formed in the first cutout 22A in the direction parallel to the longitudinal direction of the second divided storage space 28B, that is, in the direction substantially perpendicular to the longitudinal direction of the battery cell 26. It is separated from the position where the notch region 24 is provided. In the example of FIG.6 and FIG.7, notch area | region is not provided in 2nd division | segmentation storage space 28BA corresponding to 1st division | segmentation storage space 28AA of the upper left of 1st division | segmentation holder 22A. Instead, in the second divided storage space 28BB adjacent in the horizontal direction, a second notch region 25 is provided as shown in the rear right side of the perspective view of FIG. On the other hand, in the corresponding first divided storage space 28AB of the first divided holder 22A, no first cutout region is provided as shown in the lower right of FIG. Thus, by making it the structure which makes a notch area | region continuous and is made to separate, the fall of heat dissipation can be suppressed as mentioned above. In particular, by concentrating the notch area in other battery cells without concentrating the notch area in the storage space for storing the same battery cell, the heat dissipation is reduced only for specific battery cells, resulting in a decrease in battery performance. You can avoid the situation of lack of balance.

  Further, the configuration in which the first notch region 24 and the second notch region 25 are spatially separated is not limited to the circumferential direction of the battery cell as described above, but is separated in the longitudinal direction of the battery cell. It can also be made. For example, in the example of FIG. 6, both the first divided storage space 28AE of the first divided holder 22A and the second divided storage space 28BE of the second divided holder 22B corresponding to the first divided storage space 28BE are on the left side. The second notch region 25 is formed. In the example of FIG. 7, the first notch region 24 on the left side and the second notch space 24 </ b> BD of the first divided holder 22 </ b> A and the second divided storage space 28 </ b> BD of the second divided holder 22 </ b> B corresponding to the first divided holder 22 </ b> A A two-notch region 25 is formed. Thus, even if it is spaced apart in the longitudinal direction of the battery cell, it is possible to disperse the region with inferior heat dissipation and suppress the decrease in heat dissipation performance.

  Such a notch region is preferably provided in a region where the storage space of adjacent battery cells does not contact, in other words, in a site where a space is formed between the storage spaces. This is particularly suitable for battery holders in which the distance between the storage spaces is not constant. For example, in the battery holders 92 and 192 previously developed by the present inventor shown in FIGS. 11 to 19, the storage space 28 is formed so as to completely cover the periphery of the battery cell with the storage wall 29. As a result, there is no problem in the area where the two storage spaces 28 are in contact with each other, but a space (dead space) is formed between the storage spaces 28 in a portion where three or more storage spaces 28 are adjacent to each other. In order to form the storage walls 29 that define the storage spaces 28 in such a part, a resin lump BK that fills the dead space is formed, for example, as shown in FIG. Such a resin lump BK has a wall thickness that is significantly different from that of other parts, so that so-called shrinkage tends to occur when the resin is cured, and the accuracy of resin molding is reduced. In order to avoid this, as shown in FIG. 19, as a so-called meat stealing structure that reduces the amount of resin, a cylindrical round pin MP is arranged on the resin block BK, or a wall with a certain wall thickness is used. It is conceivable to form a closed space HK (FIGS. 12 and 14 to 16). However, in the case where the round pin MP is arranged, there is a problem that the die strength is weakened and the die cost is increased as the pin length is increased. In addition, the resistance to punching at the time of mold molding is increased, and the moldability is inferior. In addition, since the thickness cannot be made completely uniform with a round pin, the occurrence of sink marks cannot be completely eliminated. Similarly, in the method of forming the closed space HK, problems such as a rise in mold cost, an increase in punching resistance, and mold strength occur.

In view of such a problem, in the present embodiment, as described above, a notch region is provided at a different portion with respect to the storage space for storing the battery cells, and the thickness of the storage spaces is maintained constant. be able to. With such a configuration, the mold structure can be simplified to improve the strength, the mold cost can be suppressed, the punching resistance can be reduced, and the moldability is improved. Moreover, since the thickness of the storage wall of the battery holder that is resin-molded can be made constant, the amount of resin used can be reduced, cost reduction, shortening of the resin curing time, and suppression of sink marks can be achieved. In particular, since the shape of the mold can be simplified, the shape can be made to have a high strength, so that the mold can be maintained at a sufficient strength and the punching resistance can be reduced to protect the mold. Thereby, when the battery cells are irregularly arranged in the battery holder and the distance between the adjacent battery cells is not constant, in other words, when the thickness of the storage wall defining the storage space is uneven, A so-called meat stealing structure can be effectively provided.
(Modification)

  In the above description, the battery holder in which the battery cells are arranged in a grid pattern has been described. However, the present invention is not limited to this arrangement, and the present invention is preferably applied to a battery holder having an offset arrangement in which the battery cells are eccentric. it can. Such an example is shown in FIGS. In these drawings, FIG. 20 is a partial rear view showing a portion provided with a cutout region of a first divided holder 22A ′ according to a modification, and FIG. 21 is a perspective view showing the first divided holder 22A ′ of FIG. 22 is a perspective view of the first divided holder 22A ′ of FIG. 21 as viewed from the back, FIG. 23 is a cross-sectional perspective view showing a state in which the first divided holder 22A ′ of FIG. 22 is joined to the second divided holder 22B ′, FIG. Respectively show enlarged views showing the second divided holder 22B ′ of FIG.

  The battery holder 122 shown in these drawings is provided with a notch region in the battery holder 192 previously developed by the present inventor shown in FIGS. That is, by providing the first notch region 24 in which a part of the storage wall 29 is notched as shown in FIG. While eliminating, the decrease in heat dissipation is suppressed. Particularly in this example, as shown in FIGS. 20 to 22, the storage spaces 28 arranged in a staggered manner between the battery cells stacked in the vertical direction in the first divided holder 22 </ b> A ′ and the battery cells adjacent to the left and right. The first cutout region 24 is provided between the storage space located in the upper stage and the storage space located in the lower stage among the adjacent storage spaces. The same arrangement is also adopted for the second divided holder 22B '. At this time, as shown in FIGS. 23 to 24, in the second divided storage space 28 </ b> B corresponding to the first divided storage space 28 </ b> A in which the first cutout region 24 is provided in the first divided holder 22 </ b> A ′, Region 25 is provided. In other words, the storage space provided with a plurality of cutout areas and the storage space provided with no cutout areas are arranged in a zigzag manner.

  However, the present invention is not limited to this configuration, and the second cutout area is not provided in the second divided storage space of the second divided holder that communicates with the first divided storage space provided with the first cutout area in the first divided holder. On the contrary, the second divided storage space of the second divided holder that communicates with the first divided storage space that is not provided with the first cutout region by the first divided holder is configured to provide the second cutout region. Also good. By doing in this way, the difference in the heat dissipation by the presence or absence of the notch area | region in each storage space can be suppressed, and the thermal equalization of a battery cell can be aimed at. As described above, the notch region is not limited to the configuration provided in the same battery cell, but can be provided in the adjacent battery cell, thereby obtaining an advantage that the amount of resin used in the battery holder forming the storage space can be constant. That is, by providing the first cutout area with the first divided holder, the second cutout area of the second divided holder is the first cutout area while the storage wall defining the first divided storage space is stealed. It is provided in a second divided storage space that constitutes a storage space adjacent to the divided storage space. Thereby, the resin amount of the storage wall in contact with the adjacent battery cells can be maintained uniformly. That is, since the heat capacity can be made constant by making the amount of resin in contact with adjacent battery cells constant, an effect of suppressing variation in heat dissipation performance can be obtained. This can adjust the amount of resin on the storage wall constituting the storage space, and can also be used to equalize heat dissipation. For example, when the first divided holder and the second divided holder are not divided into two along the longitudinal direction of the battery cell, and the lengths are different, the area of the storage wall that contacts the battery cell by adjusting the size of the notch region In addition, the volume considering the wall thickness can be made constant between the divided holders, and a divided structure of battery holders having the same heat capacity can be realized.

  Needless to say, not all the storage spaces need to be provided with cutout regions, and there are storage spaces that are not provided with cutout regions. As described above, in the storage space where the distance between the battery cells is not constant, especially in the case where the space between the battery cells is wide, a structure for stealing the storage wall that defines the storage space is required. A cutout area is provided in the storage space. In other words, it is not necessary to provide a notch area in the storage space where the distance between the battery cells is short. Even when the storage spaces are separated from each other, it is sufficient to provide a cutout area only in a specific storage space. Therefore, it is not necessary to provide notch areas in all the storage spaces.

  The battery pack and the battery holder for the battery pack according to the present invention can be suitably used as a power supply device for an assist bicycle. In addition, these battery packs and battery holders are mainly mounted on an electric vehicle and used to supply power to a driving motor, for example, as a power source for an electric motorcycle, an assist bicycle, an electric wheelchair, an electric tricycle, an electric cart, etc. The However, the present invention does not specify the application of the battery pack, and can also be used as a power source for various electric devices used outdoors such as electric tools.

DESCRIPTION OF SYMBOLS 100 ... Battery pack 10 ... Outer case 14, 14A ... End plate 16 ... Output terminal connector 20, 20B ... Core pack 21 ... Battery block 22, 122 ... Battery holder 22A, 22A '... First division holder 22B, 22B' ... 2nd division holder 24 ... 1st notch area | region 25 ... 2nd notch area | region 26 ... Battery cell 26b ... End surface electrode 27 ... Holding member 28 ... Storage space; 28A, 28AA, 28AB, 28AD, 28AE ... 1st division | segmentation storage space 28B, 28BA, 28BB, 28BD, 28BE ... second divided storage space 29 ... storage wall 30 ... circuit board 31 ... substrate holder 40, 40B, 40C ... lead plate 92, 192 ... battery holder BK ... resin block MP ... round pin HK ... closed space

Claims (10)

A plurality of battery cells (26) having an outer shape extended in one direction;
A battery holder (22; 22B) in which a plurality of battery cells (26) are individually defined so as to be adjacent to each other.
A battery pack comprising:
The battery holder (22; 22B) is divided into a first divided holder (22A) and a second divided holder (22B) in the longitudinal direction of the battery cell (26),
The first divided holder (22A) and the second divided holder (22B) are respectively a first divided storage space (28A) and a second divided storage space (28B) for storing a part of the battery cell (26). Is defined,
By joining the first divided holder (22A) and the second divided holder (22B), the first divided storage space (28A) and the second divided storage space (28B) are on substantially concentric axes. Connected to define the storage space,
The first divided holder (22A) has a part of the storage wall (29) that defines the first divided storage space (28A) in a region where the first divided storage spaces (28A) are separated and adjacent to each other. Forming a cutout first cutout area (24),
The second divided holder (22B) includes a part of a storage wall (29) that defines the second divided storage space (28B) in a region where the second divided storage spaces (28B) are separated and adjacent to each other. Forming a cutout second cutout region (25),
The battery pack, wherein the first notch region (24) and the second notch region (25) are provided at positions separated from each other so as not to be continuous. The battery pack according to claim 1,
The first cutout region (24) or the second cutout region (25) is formed in part in the longitudinal direction of the first divided storage space (28A) and the second divided storage space (28B). A battery pack characterized by The battery pack according to claim 2,
The first cutout region (24) or the second cutout region (25) is about 1/3 to 1/2 of the length of the first divided storage space (28A) or the second divided storage space (28B). A battery pack, characterized in that it is provided over a wide area. The battery pack according to any one of claims 1 to 3,
The second cutout area (25) is formed from the position of the storage wall (29) corresponding to the position where the first cutout area (24) of the first split holder (22A) is provided, and the battery cell (26) A battery pack, wherein the battery pack is provided at a position separated in a direction substantially perpendicular to the longitudinal direction of the battery pack. The battery pack according to any one of claims 1 to 3,
The second cutout area (25) is formed from the position of the storage wall (29) corresponding to the position where the first cutout area (24) of the first split holder (22A) is provided, and the battery cell (26) The battery pack is provided at a position spaced apart in the longitudinal direction. The battery pack according to any one of claims 1 to 5,
In the first divided holder (22A), the first cutout region (24) is spaced apart so as not to be continuous in the adjacent first divided storage space (28A). . The battery pack according to any one of claims 1 to 6,
A battery pack characterized in that the distance between adjacent storage spaces differs at least in part. The battery pack according to any one of claims 1 to 7,
The battery pack, wherein the storage space is arranged in an offset shape. The battery pack according to any one of claims 1 to 7,
The battery pack, wherein the storage space is arranged in a grid pattern. A battery holder that defines a plurality of storage spaces for individually storing a plurality of battery cells (26) having an outer shape extended in one direction so as to be adjacent to each other,
In the longitudinal direction of the battery cell (26), it is divided into a first divided holder (22A) and a second divided holder (22B),
The first divided holder (22A) and the second divided holder (22B) are respectively a first divided storage space (28A) and a second divided storage space (28B) for storing a part of the battery cell (26). Is defined,
By joining the first divided holder (22A) and the second divided holder (22B), the first divided storage space (28A) and the second divided storage space (28B) are on substantially concentric axes. Connected to define the storage space,
The first divided holder (22A) has a part of the storage wall (29) that defines the first divided storage space (28A) in a region where the first divided storage spaces (28A) are separated and adjacent to each other. Forming a cutout first cutout area (24),
The second divided holder (22B) is located at a position corresponding to the first cutout region (24) of the first divided holder (22A) on the joint surface with the first divided holder (22A). The storage wall (29) that defines the storage space (28B) is not provided with a cutout, and is provided with a second cutout region (25) in which a part of the storage wall (29) is cut out at another position. A battery holder.

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