JP5399121B2 - Pack battery - Google Patents

Description

  The present invention relates to a battery pack having a handle on an exterior case, and more particularly to a technique for improving safety around the handle.

Secondary batteries such as nickel metal hydride batteries and lithium ion batteries that can be used repeatedly are used as power sources for electric assist bicycles and electric tools. One or more of these secondary batteries are housed as a unit cell in an exterior body (exterior case) made of molded resin in accordance with the output and form of the electronic device to be fed, and are used in the form of a pack battery. In some cases, the battery pack may be provided with a handle portion so that the user can easily handle the battery pack.
Here, FIGS. 5A and 5B are a front view and a side view showing a configuration example of a conventional battery pack. The battery pack shown in the figure includes a plurality of unit cells, a control board and the like housed between a pair of resin-molded outer cases 10X and 20X. In FIG. 5B, a connector for supplying power by electrically connecting to a power supply target device is provided at an end portion on the right side surface. On the left side of the exterior case 10X, as shown in the rear view of the exterior case 10X in FIG. 5C, a handle portion 100X for the user to lower by hand is disposed by integral molding. The configuration of the handle portion 100X is such that a plurality of hollow portions 1010X are formed at predetermined intervals as shown in an enlarged perspective view (FIG. 6A) showing the configuration of the region A from the viewpoint of resin molding convenience and ensuring strength. The so-called hollow rib structure is formed.

JP 2008-66000 A

  Here, when the user accidentally drops the battery pack, the handle portion may receive an impact and cause brittle fracture. At this time, as shown in FIG. 6B showing the state of the handle portion at the time of breakage, the breakage portion may be sharply cracked in the thickness direction of the handle portion, resulting in a dangerous shape for the user. . Further, if the outer case of the battery pack is cracked obliquely in this way, the contents may be exposed.

  In order to deal with such problems, measures are taken to increase the resin wall thickness of the outer case or to change the resin material to a material having high strength. However, in these cases, although a certain improvement in the limit strength can be expected, there is a risk that it will break at a stretch when the limit strength is exceeded, leading to an unexpected situation for the user and a separate issue in safety. In addition, there is a risk of increasing the manufacturing cost due to the increased resin material and alternative resin material.

Thus, in the battery pack, it is desired to take appropriate safety measures with respect to the damage of the outer case.
The present invention has been made in view of the above problems, and provides a battery pack capable of preventing cracking of a member and exhibiting high safety at a relatively low cost even when a handle portion is damaged. For the purpose.

In order to solve the above-described problems, the present invention provides a battery pack in which a unit cell is housed in an exterior body having a resin handle, and the handle is disposed at a predetermined interval inside a long handle body. It is configured to have a plurality of arranged hollow parts, and a meat stealing part is formed on the inner surface of the handle body facing the hollow part.
Here, the handle main body may have an arc shape in cross section that crosses the hollow portion along the short direction of the handle main body, and the meat stealing portion may be formed along the arc.

The meat stealer may have a wedge shape in cross section along the longitudinal direction of the handle body.
Alternatively, the meat stealer may be configured such that the cross-sectional shape along the longitudinal direction of the handle body is a curved surface. These wedge-shaped and curved-shaped stealing portions can be used together in the handle portion.

  In the battery pack of the present invention having the above-described configuration, the member is cracked when the handle portion is broken by providing a meat stealing portion on the inner surface of the handle body facing the hollow portion of the handle portion of the exterior body (case). The failure mode is controlled to prevent and intentionally break or bend across the meat stealer. For this reason, in the present invention, as shown in FIG. 6B, the handle portion is prevented from being obliquely cracked to form a sharp fracture portion, and even if it is fractured, the fracture surface becomes a substantially flat surface. Controlled. For this reason, there is a low possibility that the user will be injured at the broken portion, and good safety can be exhibited. In addition, it is possible to prevent a problem that the contents are exposed due to the exterior body being largely obliquely cracked.

When the meat stealing portion having a wedge-shaped cross-section is formed along the longitudinal direction of the handle body, the fracture form can be adjusted to be broken, and when the meat stealing portion having a curved cross-sectional shape is formed, a certain load is applied. It can be adjusted so that it bends.
Further, in the present invention, since the breaking / bending position can be guided to the arrangement position of the meat stealing portion, it is possible to design the battery pack in consideration of the breaking position and the bending position in advance, which is extremely difficult in manufacturing. It is effective for.

  Furthermore, in the conventional handle part, cracks may suddenly occur at the moment when a certain limit strength is exceeded, but in the battery pack of the present invention, by providing a meat stealing part, a stress exceeding a certain level is applied to the handle part. When applied, the member near the meat stealing part is deformed before the breakage. By visually recognizing this deformation from the outside, the user can be alerted before the breakage occurs, so that extremely high safety can be exhibited.

Moreover, by providing the handle portion with the meat stealing portion, the breaking limit point of the handle portion can be lowered as compared with the conventional case. Therefore, the risk of the handle portion breaking at a stretch when a high impact is applied is suppressed, and safety is also improved in this respect.
Since the present invention can be realized by providing a predetermined stealing portion in the handle portion in a battery pack having a conventional configuration, it can be realized without increasing the amount of resin material used or using an expensive resin material. . For this reason, it can be constructed at a relatively low cost and has high feasibility.

1 is a set diagram illustrating a configuration of a battery pack according to Embodiment 1. FIG. It is a figure which shows the structure of an exterior case. It is a partial set figure which shows the structure around the handle | steering-wheel part of an exterior case. It is a figure for demonstrating the state of the handle | steering-wheel part at the time of a fracture | rupture. It is a figure which shows the structure of the conventional battery pack and exterior case. It is a figure which shows the structure around the handle | steering-wheel part of the exterior case in the conventional battery pack, and the state of the handle | steering-wheel part at the time of a fracture | rupture.

Each embodiment of the present invention will be described below, but the present invention is naturally not limited to these configurations. That is, the present invention can be implemented with appropriate modifications without departing from the technical scope of the present invention.
<Embodiment 1>
FIG. 1 is an assembled view showing the configuration of the battery pack 1 of the first embodiment. 2A to 2F are diagrams showing the configuration of the outer case 10. (A), (b), (c), (d), (e), and (f) of FIG. 2 are the right side view, front view, left side view, back view, and top view of the outer case 10 in the same order. The figure and the bottom view are shown.

As shown in FIG. 1, the battery pack 1 is a long rectangular parallelepiped with the y direction as a long direction and the X direction as a short (width) direction. A core pack 30 that is a power generation element is housed between an exterior body composed of a pair of exterior cases 10 and 20, and the cases 10 and 20 are fixed by screwing using bosses provided on the inner surfaces of the respective exterior bodies. .
Here, the core pack 30 is configured by arranging a plurality of cylindrical unit cells 303 in a predetermined arrangement and sandwiching them between a pair of lead plates (only 304 shown) and holders 301 and 302. The core pack 30 is connected to the connector 40 by a wiring (not shown), and the unit cell 303 is charged and discharged through the connector 40. In FIG. 1, reference numeral 50 denotes a configuration example of a terminal connected to the connector 40, but the terminal shape is not limited to this.

  Here, the unit cell 303 uses a lithium ion secondary battery, and a total of 80 unit cells 303 are connected in a predetermined arrangement (in the figure, 10 series × 4 arrangement). With this connection, an output of 37 V and 7000 Ah can be obtained as the overall output of the battery pack 1. This output assumes that the battery pack 1 is applied to an electrically assisted bicycle. Note that the connection method of the unit cells 303 is arbitrarily set according to a request on the power supply target device side.

  When a lithium ion secondary battery is used as the unit cell 303, a control board (not shown) is further accommodated inside the outer cases 10 and 20. The control board is electrically connected to the unit cell 303 and the connector 40, and controls the output of the unit cell 303, and interrupts the energization at the time of thermistor element for temperature management of the unit cell 303 and thermal runaway. A PCT element that performs this function, a microcomputer having a function of calculating the remaining capacity and detecting an abnormality, etc. are mounted.

The pair of outer cases 10 and 20 are both injection-molded using an engineering plastic material (ABS in this case) that is excellent in mechanical strength and insulation.
As shown in FIGS. 1 and 2, the outer case 10 has a rectangular parallelepiped tray portion 101, a fixed portion 102 is disposed at one end portion along the longitudinal direction, and a handle portion is disposed at the other end portion. 100 is arranged. On the back surface of the handle portion 100, a plurality of hollow portions 1020 are arranged at a predetermined interval as shown in FIG. 2D from the viewpoint of resin molding and ensuring a certain strength, and a hollow rib structure is formed. ing. Here, the handle unit 100 is easy to handle by the user, that is, the battery pack 1 can be easily attached to and detached from the electronic device (electric bicycle) and the charger, and can be easily carried. As described above, the handle portion 100 is provided in the exterior case.

The outer case 20 has a rectangular parallelepiped tray portion 201 having the same size and shape as the tray portion 101, and a slit 200 for fitting the connector 40 is formed at one end portion along the longitudinal direction. It becomes. The core pack 30 is stored in the tray units 101 and 201.
The fixing portion 102 is used as a portion for fixing and connecting the battery pack 1 to a power supply target device together with pins 103 and 103 protruding from the outer case provided on both sides thereof. Further, it is also used as a space for enclosing the connector 40.

3A is an enlarged perspective view showing the configuration of the region A in FIG. FIG.3 (b) shows the BB arrow sectional drawing of FIG.2 (d).
As shown in each of these drawings, the handle portion 100 has a long handle main body in which the X direction is mainly the longitudinal direction and both end portions in the same direction curve toward the tray portion 101 side. Inside the handle body, a plurality of hollow portions 1010 are arranged at predetermined intervals along the longitudinal direction. Due to the presence of the hollow portion 1010, the cross-sectional shape of the handle body along the short direction perpendicular to the longitudinal direction is substantially arcuate. A plurality of fracture grooves 1020 are formed along the arc on the inner surface of the handle body facing each hollow portion 1010. The breaking groove 1020 is configured as a meat stealing portion (thin portion) of the resin member of the handle body. The forming method includes molding with an injection mold, but it is also possible to form the handle portion and then cut the member.

The fracture groove 1020 is formed such that the cross-sectional shape along the longitudinal direction of the inner surface of the handle body facing the hollow portion 1010 has a wedge-shaped edge toward the outer side in the thickness direction of the handle portion 100.
By forming the rupture groove 1020 having such a shape, in the battery pack 1 of the present invention, the safety at the time of rupture of the handle portion 100 is dramatically improved as compared to the conventional case.

Hereinafter, this effect will be specifically described with reference to FIG. 4A showing the state of the handle portion at the time of breakage.
When the battery pack 1 is used, when a user gives an impact such as a drop to the battery pack 1 and a load of a certain level or more is applied to the handle portion 100, the resin member constituting the handle portion 100 causes brittle fracture. In this case, the handle portion 100 undergoes a plastic deformation under the external force, and when the further deformation proceeds, the handle portion 100 is broken.

As shown in FIG. 4A, the fracture mode at this time is that the fracture portion is intentionally guided to the fracture groove 1020 and crosses the wedge-shaped edge of the fracture groove 1020 (the top in the cross-sectional shape). Is cut across the thickness direction. As a result, a substantially flat fracture surface is formed along the thickness direction of the handle portion 100.
As described above, in the battery pack 1, by guiding the handle portion 100 to form a flat fracture surface, the resin member is cracked obliquely in the thickness direction as in the conventional handle portion, and a sharp fracture portion is formed. Can be effectively prevented. Therefore, even if the handle portion is broken, the user is less likely to be injured and good safety can be exhibited. In addition, by suppressing the destruction mode in which the member breaks obliquely, it is possible to effectively prevent the problem that the outer case 10 and the outer case are largely cracked and the contents are exposed.

Further, in the battery pack 1, the break position of the handle portion 100 can be guided by adjusting the disposition position of the break groove 1020 in the handle portion 100. For this reason, the battery pack 1 can be designed in consideration of the break position in advance. This advantage is very effective in manufacturing.
Moreover, in the battery pack 1, by providing the fracture groove 1020, the limit strength of the handle portion 100 can be intentionally lowered as compared with the conventional battery. Therefore, the danger that the handle part 100 will break at a stretch when a high impact is applied is suppressed, and safety can be improved in this respect as well.

Furthermore, such a battery pack 1 can be realized simply by forming a predetermined breaking groove 1020 in the hollow portion of the conventional handle portion, and there is no need to increase the amount of resin material used or use an expensive resin material. . For this reason, it has the merit which can be comprised by comparatively low cost, and can demonstrate the outstanding feasibility on production.
Note that the shape of the fracture groove 1020 is not limited to a strict wedge-shaped cross-sectional shape, and may be any shape that has the edge toward the outside in the thickness direction of the handle portion. For example, a shape having a parabolic cross-sectional shape as a base and an edge portion at a portion corresponding to the apex thereof may be used. A plurality of edges may be formed in one groove.

<Embodiment 2>
The second embodiment will be described with a focus on differences from the first embodiment.
The meat stealing portion provided in the handle portion 100 is not limited to the breaking groove for inducing breakage, and the bending groove for bending the member when a certain load or more is applied to the handle portion, You may form with a fracture | rupture groove | channel.

FIG. 4B is a diagram showing a state in which the handle portion using such a bent groove 1030 in combination with the fracture groove 1020 is broken. The bent groove 1030 is formed as a curved (here, parabolic) groove whose cross-sectional shape along the longitudinal direction of the handle portion 100 does not have an edge on the inner surface facing the hollow portion 1010 of the handle portion 100.
When the limit strength is applied to the handle portion 100, a fracture portion is formed in the fracture groove 1020 as described above. As a result of forming a flat fracture surface at the fractured portion, high safety is exhibited as in the first embodiment. In addition to this effect, the resin member bends inward by receiving an external force at the portion where the bent groove 1030 is formed, so that the impact is well absorbed by this plastic deformation. As described above, in the battery pack according to the second embodiment, since the bending groove 1030 is employed, the occurrence of breakage itself can be effectively reduced, and therefore, the possibility that members are scattered at the time of breakage is small. Further, when the impact is light, the handle portion 100 can be bent only and not broken. Thereby, it is possible to further improve safety.

  In the second embodiment, since the handle portion 100 is deformed in the bending groove 1030 before the handle portion 100 breaks, the user can recognize an abnormality occurring in the handle portion 100 at an early stage as viewed from the outside. In the conventional handle part, there is a case where the crack suddenly occurs at a moment when a certain limit strength is exceeded, and it is difficult for the user to know the abnormality of the handle part until immediately before breaking, but in the battery pack of the second embodiment, By deforming the handle before the brittle fracture occurs, the user can be alerted in advance. In this respect as well, the battery pack of Embodiment 2 can exhibit excellent safety.

  In the second embodiment, the configuration in which the break groove 1020 and the bent groove 1030 are used in combination in the handle portion 100 is illustrated, but only the bent groove 1030 can be provided in the handle portion 100. In this case, the handle portion 100 is specialized to bend around a portion to which an impact is applied at the time of abnormality, and to absorb the impact to ensure safety. When a further force is applied, the bent groove 1030 is broken. Therefore, the bent groove 1030 also functions as a fracture groove.

Note that the degree of effect obtained by providing the breaking groove 1020 and the bending groove 1030 correlates with the characteristics and usage of the member of the handle portion 100, the number of grooves, and the depth of the groove. Note that the handle portion 100 should be designed.
In addition, when the fracture groove 1020 and the bending groove 1030 are used in combination, the number of the arrangement in the handle portion 100 is not limited. However, for example, when it is desired to give priority to the effect of bending as described above, It is preferable to adjust the number more than the number of the breaking grooves 1020.

<Other matters>
In the above-described embodiment, the configuration in which the fracture groove and the bending groove are provided on the inner surface of the handle portion that can be visually recognized from the outside has been described, but the configuration is not limited thereto. These meat stealing portions can be provided inside the resin constituting the handle portion or on the secondary appearance surface.
In the present invention, the meat stealing portion having a predetermined shape is provided in the exterior case portion other than the handle portion, and the safety when the exterior case is broken can be further enhanced. For example, the outer peripheries of the tray portions 101 and 201 of the outer casings 10 and 20 shown in FIG. 1 are formed so as to form a hollow rib structure in the same manner as the handle portion 100, and in each hollow rib structure, the fracture groove 1020 and the bent groove are formed. A plurality of meat stealing portions corresponding to 1030 are formed at a predetermined interval. In this case, when an impact is applied from the outside in the vicinity of the joint between the outer cases 10 and 20, the member is prevented from being largely broken obliquely in the same manner as the handle portion 100 described above. Will be demonstrated.

  Similarly, each main surface portion of the tray portions 101 and 201 may be configured to have a hollow rib structure including the predetermined meat stealing portion. In this configuration, the tray portions 101 and 201 can be formed by combining (superimposing) two or more members, respectively, or can be configured as an integrally molded product by devising a mold. In this case, it is desirable because it is possible to further enhance the safety of the battery pack 1 such that the breakage of the outer casings 10 and 20 is prevented from being obliquely broken and the exposure of the contents can be effectively prevented.

Such a hollow structure including the predetermined meat stealing portion may be provided in combination with the handle portion 100 and the other exterior cases 10 and 20, or only the exterior case 10 and 20 except the handle portion 100. May be provided.
In the above embodiment, the lithium ion secondary battery is exemplified as the unit cell, but the present invention is not limited to this. In addition, various secondary batteries such as a nickel metal hydride battery, a nickel cadmium battery, and a lithium ion polymer battery can be given. Further, the shape of the unit cell is not limited to the cylindrical shape, and may be a square shape or a dedicated shape. The number of unit cells can also be set arbitrarily.

  The battery pack of the present invention can be widely used as a power source for, for example, a power-assisted bicycle or a power tool. In particular, it is considered effective when a relatively large battery pack is used safely.

DESCRIPTION OF SYMBOLS 1 Pack battery 10 Exterior case 20 Exterior case 30 Core pack 40 Connector 100 Handle part 101, 201 Tray part 102 Fixed part 1010 Hollow part 1020 Breaking groove (meat stealing part)
1030 Bending groove (meat stealer)

Claims (5)

A battery pack in which a unit cell is housed in an exterior body having a resin handle,
The handle is configured to have a plurality of hollow portions arranged at predetermined intervals inside an elongated handle body,
A battery pack characterized in that a meat stealing portion is formed on the inner surface of the handle body facing the hollow portion. The handle body has a circular arc cross-sectional shape that crosses the hollow portion along the short direction of the handle body,
The battery pack according to claim 1, wherein the meat stealing portion is formed along the arc. The battery pack according to claim 1 or 2, wherein the meat stealing portion has a wedge shape in cross-sectional shape along the longitudinal direction of the handle body. The battery pack according to claim 1 or 2, wherein the meat stealing portion has a curved cross-sectional shape along the longitudinal direction of the handle body. The battery pack according to any one of claims 1 to 3, wherein at least the handle portion is made of a resin in the exterior body.

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