JP2008010315A - Battery pack for hand-held electric tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique for a measure to counter vibration or shock in a battery pack for a hand-held electric tool in the batter pack for an electric tool. <P>SOLUTION: The battery pack for the electric tool 101 has a battery pack 111 comprising a plurality of unit cells 113 arranged in parallel; a container 103 for housing the battery pack 111; and a buffer material 121 coming in contact with the wall surface 103a of the container 103 and the side surface of the battery pack 111 and interposed between the container 103 and the battery pack 111. The buffer material 121 has a first buffer zone and a second buffer zone made of an elastic material in a layer, and the elastic constant of the second buffer zone is made smaller than that of the first buffer zone. The transfer of vibration or shock to the battery pack is absorbed by the first buffer zone, and dimensional dispersion in buffer material installation spaces between the container 103 and the battery pack 111 is absorbed by the second buffer zone. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery pack used as a power source for various hand-held power tools, and more particularly to a buffering technique for an assembled battery housed in a case.

A battery pack used for a hand-held power tool is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-306447 (Patent Document 1). The above publication discloses a configuration in which a plurality of rows of assembled batteries in which a plurality of cylindrical battery cells are linearly arranged in a radial direction are arranged, and an electrically insulating partition plate is arranged between the assembled batteries. Yes. The partition plate is formed in a corrugated plate shape having arc-shaped concave surfaces alternately on the front and back surfaces along the arrangement direction of the battery cells constituting the assembled battery, and a part of the peripheral surface of each battery cell is formed on each concave surface. It is set as the structure closely_contact | adhered. As a result, the relative movement between the assembled batteries and the relative movement between the battery cells are suppressed, and even if vibrations or shocks are applied to the battery pack, electrical insulation between the assembled batteries and the assembled battery are configured. Electrical insulation between the battery cells is ensured.
In the case of a battery pack used for a hand-held power tool, there is a high possibility that the battery pack will be subjected to vibration generated when the power tool is used or an impact when the battery tool is bumped or dropped when transported. With respect to measures against vibration and shock, there is still room for improvement in the conventional battery pack.
JP-A-9-306447

  This invention is made | formed in view of this point, and it aims at providing the technique which contributes to a vibration or impact countermeasure in the battery pack for handheld power tools.

In order to achieve the above object, the invention described in each claim is configured.
According to the first aspect of the present invention, the battery pack includes a battery pack composed of a plurality of battery cells arranged in parallel to each other, a container that houses the battery pack, and the container in contact with the wall surface of the container and the side surface of the battery pack. And a shock absorber interposed between the assembled batteries. The “buffer” in the present invention typically corresponds to rubber. The “battery pack” in the present invention is a variety of hand-held types such as a drilling tool such as an electric drill, a tightening tool such as an electric screwdriver, a cutting tool such as an electric circular saw, or a grinding tool such as an electric grinder. It can be widely applied to electric tools.

  As a characteristic configuration of the battery pack for a hand-held power tool according to the present invention, the buffer body has a first buffer region and a second buffer region made of an elastic material in layers. The elastic constant of the second buffer region is set smaller than the elastic constant of the first buffer region. When driving the power tool using the battery pack, the first buffer region absorbs the vibration transmitted from the power tool to the battery pack or the impact acting on the power tool or the battery pack to the assembled battery. The second buffer region absorbs the dimensional variation of the buffer arrangement space between the container and the assembled battery. Note that “layered” in the present invention refers to a state in which the first and second buffer regions overlap each other, and an aspect in which the overlapping direction intersects the arrangement direction of the plurality of battery cells corresponds to this. . Further, in the present invention, the “first buffer region” and the “second buffer region” each have a mode in which one layer is provided, a mode in which either one is provided, or a mode in which both are provided in a plurality of layers. Both are included suitably. Further, the “second buffer region” in the present invention is a mode in which, for example, by providing a plurality of protrusions having a cylindrical shape, a hemispherical shape, or a cylindrical shape, the elastic constant thereof is made smaller than that of the first buffer region. Any of the embodiments formed by an elastic material having an elastic constant smaller than that of the elastic material constituting the first buffer region is suitably included. In addition, the “dimensional variation of the buffer arrangement space” in the present invention corresponds to a dimensional variation that occurs when a container, a battery cell, or a buffer is manufactured. In addition, the “configuration for absorbing dimensional variations” means that the size in the thickness direction of the second buffer region is set in advance larger than the buffer arrangement space set between the container and the assembled battery. In addition, when the buffer body is disposed between the side surface of the assembled battery and the wall surface of the container, this corresponds to a mode of absorbing the dimensional variation of the buffer body layout space by utilizing the elastic deformation of the second buffer region.

In the configuration in which the buffer body is interposed in contact between the side surface of the assembled battery and the wall surface of the container, a space for buffer body placement is set between the side surface of the assembled battery and the wall surface of the container. Due to an error in manufacturing the battery cell constituting the battery or the buffer, there is a possibility that the buffer arrangement space may vary in size. And, for example, if the shock absorber arrangement space becomes too narrow, the shock absorber will be arranged in an unexpectedly compressed state, while if the shock absorber arrangement space becomes too wide, between the shock absorber and the container, Alternatively, there is a possibility that a gap is generated between the buffer body and the assembled battery, causing backlash, and as a result, the buffer body may not function effectively.
However, according to the present invention, the buffer body is configured to include the first buffer area and the second buffer area having an elastic constant smaller than the elastic constant of the first buffer area in a layered manner. When the assembled battery is arranged in the container via the above, the above dimensional variation can be absorbed by the elastic deformation of the second buffer region. As a result, the elastic deformation of the first buffer region when the assembled battery is arranged in the container is prevented, or even if elastically deformed, the elastic region is suppressed to a very small range. As a result, vibration and shock absorption by the first buffer region are suppressed. Function can be secured. That is, vibration generated when the electric power tool is used, or shock generated when the electric power tool is struck or dropped is absorbed mainly using the elastic deformation of the first buffer region, and the assembled battery is absorbed from the container. It is possible to prevent or reduce the transmission of the impact to the. The second buffer region has a main function of absorbing dimensional variation. However, if the second buffer region is in a state in which further elastic deformation is possible in a state of absorbing the dimensional variation, vibration, Has a shock absorbing function.

(Invention of Claim 2)
According to the second aspect of the present invention, the shock absorber in the battery pack for the hand-held power tool according to the first aspect is such that the side contacting the side surface of the assembled battery has the side shape of each battery cell constituting the assembled battery. It was set as the corresponding | compatible shape, and it was set as the structure which controls the relative movement of an adjacent battery cell by carrying out surface contact individually with respect to each battery cell. In the present invention, the “side in contact with the side surface of the assembled battery” is the first buffer region side having a larger elastic constant than the second buffer region in restricting the movement of the battery cells in the parallel direction. Although it is preferable, it may be on the second buffer region side. The “shape corresponding to the side surface shape” in the present invention typically corresponds to a substantially semicircular cross section corresponding to the columnar shape if the battery cell has a columnar shape.
According to the present invention, the configuration is such that the relative movement of the adjacent battery cells is restricted by the buffer body, so that the gap between the respective battery cells is properly maintained, thereby causing the adjacent battery cells to move relative to each other. It is possible to prevent disconnection of the conductive wires connecting the battery cells to be obtained.

(Invention of Claim 3)
According to a third aspect of the present invention, in the battery pack for a hand-held power tool according to the first or second aspect, on either side of the container and the shock absorber, the other of the container and the shock absorber is provided. An engaging portion that protrudes toward the side is formed, and an engaging recess that can engage with the engaging portion is provided on the other side, and the engaging portion engages with the engaging recess to cushion the container. It was set as the structure by which the position shift of a body is prevented.
According to the present invention, the configuration in which the buffer body is prevented from being displaced with respect to the container by the engagement between the engagement portion and the engagement recess, resulting in the displacement of the buffer body with a simple structure. It is possible to prevent the buffer body from being crushed and thereby maintain the function of the buffer body.

  According to the present invention, in a battery pack for a hand-held power tool, a technique that contributes to measures against vibration or impact is provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the overall configuration of a battery pack for a handheld power tool, and FIG. 2 is a cross-sectional view showing the overall configuration of the battery pack for a handheld power tool. As shown in FIGS. 1 and 2, the battery pack 101 according to the present embodiment includes a substantially rectangular box-shaped battery case 103 whose upper side is opened to accommodate a battery, and an upper opening portion of the battery case 103 is covered. The battery cover 105, the assembled battery 111 (see FIG. 2) disposed in the battery case 103, and the rubber mat 121 (see FIG. 2) disposed between the assembled battery 111 and the battery case 103. And the main constituent. The battery case 103 corresponds to a “container” in the present invention. The rubber mat 121 corresponds to the “buffer” in the present invention. The battery pack 101 is detachably attached to a tool main body region of an electric tool not shown for convenience. However, the configuration for the attachment is not particularly related to the present invention, so the illustration and description are omitted. Omitted.

  As shown in FIG. 2, the assembled battery 111 is formed by a plurality of (five in the present embodiment) battery cells 113 that are formed in a columnar shape and arranged in parallel to each other so as to form a row in the radial direction. Has been. Each battery cell 113 is connected (connected) to each other by conductive wires (not shown for convenience) so that adjacent battery cells 113 are arranged with a slight gap in the arrangement direction and are connected in series. The assembled battery 111 can be detached from the battery case 103 so as to cover the upper opening of the battery case 103 while being accommodated side by side on the rubber mat 121 disposed on the bottom surface 103a which is the wall surface in the battery case 103. The battery cover 105 is attached to the battery cover 105.

  The structure of the rubber mat 121 is shown in FIGS. The rubber mat 121 is made of a synthetic rubber capable of elastic deformation having excellent heat resistance, oil resistance, flame retardancy, and the like, and is formed in a substantially rectangular shape corresponding to the inner shape of the battery case 103. The rubber mat 121 is disposed on the bottom surface 103 a of the battery case 103 as an insole for the assembled battery 111. The rubber mat 121 has an upper surface side region 123 that faces the side surface of the battery cell 113 and a lower surface side region 125 that faces the bottom surface 103 a of the battery case 103. In the upper surface region 123, five contact surfaces 123a having a substantially semicircular cross section corresponding to the side surface shape of each battery cell 113 are formed side by side in the battery arrangement direction, and each contact surface 123a is shown in FIG. Thus, it is set as the structure which controls the relative movement of the battery cell 113 which adjoins by making the whole surface contact individually with respect to each battery cell 113. FIG. Further, the contact surfaces 123a are formed with a parallel interval so that adjacent battery cells 113 are placed in a non-contact state with a slight gap in the arrangement direction.

  As shown in FIG. 6, concave portions 125a and convex portions 125b having a rectangular cross section are alternately formed in the lower surface side region 125 of the rubber mat 121 in the parallel direction of the contact surface 123a. The concave portion 125a and the convex portion 125b extend linearly in a direction (vertical direction in FIG. 6) intersecting the parallel direction of the contact surface 123a. Each recess 125a is formed with a plurality of columnar protrusions 125c protruding from the bottom surface of the recess 125a toward the bottom surface 103a of the battery case 103 in a group. The protrusions 125c are formed at predetermined intervals along the extending direction of the recess 125a, and the protruding end surfaces thereof are set to be substantially flush with the end surfaces (surfaces) of the protrusions 125b. Further, in the lower surface side region 125, two horizontal grooves 125d extending in a direction intersecting with the extending direction of the recess 125a and two vertical grooves 125e extending in a direction intersecting with the horizontal groove 125d are formed. Yes. The depths of the horizontal grooves 125d and the vertical grooves 125e are formed deeper than the recesses 125a.

  As described above, in the present embodiment, the lower surface side region 125 of the rubber mat 121 is provided with the concave portion 125a, the convex portion 125b, the protrusion 125c, and the horizontal and vertical grooves 125d and 125e, so The elastic constant is set to be smaller than 123. As a result, the lower surface side region 125 can be deformed (collapsed) more easily than the upper surface side region 123. That is, the rubber mat 121 has an upper surface side region 123 and a lower surface side region 125 having different elastic constants in a direction intersecting with the arrangement direction of the battery cells 113 (a direction in which the side surface of the assembled battery 111 and the bottom surface 103a of the battery case 103 face each other). The two-layer structure. The upper surface side region 123 corresponds to a “first buffer region” in the present invention, and the lower surface side region 125 corresponds to a “second buffer region” in the present invention. The “elastic constant” of the lower surface region 125 can be appropriately adjusted by changing the depth and width of the recess 125a, the thickness of the protrusion 125c, the shape, size, number, and the like of the horizontal and vertical grooves 125d and 125e. Is possible.

  On the bottom surface 103a of the battery case 103, as shown in FIG. 8, a plurality of reinforcing ribs 103b projecting upward by a predetermined length are formed. Each rib 103b is inserted into a through hole 121a of a rubber mat 121 disposed in the battery case 103, so that the rubber mat 121 disposed on the bottom surface 103a of the battery case 103 is not displaced in a direction parallel to the bottom surface 103a. Secure to. That is, the rib 103b and the through hole 121a constitute a means for preventing the displacement of the rubber mat 121. The plurality of through holes 121a formed in the rubber mat 121 penetrate from the lower surface side to the upper surface side of the rubber mat 121, and in the present embodiment, near the respective corners on each diagonal line of the rectangular rubber mat 121. It is formed at four places, that is, at the boundary portion of the contact surface 123a, which is a region where the thickness of the rubber mat 121 is the largest, thereby ensuring the insertion depth of the rib 103b with respect to the through hole 121a. The rib 103b of the battery case 103 corresponds to the “engagement portion” in the present invention, and the through hole 121a of the rubber mat 121 corresponds to the “engagement recess” in the present invention.

  As shown in FIG. 2, the assembled battery 111 disposed in the battery case 103 is covered with a battery cover 105 that is mounted so as to cover the upper opening of the battery case 103. At this time, the pressing pad 105 a provided on the battery cover 105 presses each battery cell 113 constituting the assembled battery 111 toward the bottom surface 103 a of the battery case 103. Thus, the assembled battery 111 is pressed and fixed to the rubber mat 121 and accommodated in the battery case 103 in a stable state without rattling.

  The battery pack 101 according to the present embodiment is configured as described above. In the present embodiment, the rubber mat 121 is interposed between the assembled battery 111 and the battery case 103. For this reason, for example, vibration generated when the power tool is used, or impact when the power tool or the battery pack 101 is hit or dropped when the power tool is carried are absorbed using elastic deformation of the rubber mat 121. In addition, it is possible to reduce the transmission of vibration or impact from the battery case 103 to the assembled battery 111. Thereby, the assembled battery 111 can be protected from vibration and impact.

  In the present embodiment, the rubber mat 121 has a substantially semicircular contact surface corresponding to the side surface shape of each cylindrical battery cell 113 constituting the assembled battery 111 in the upper surface side region 123 facing the side surface of the assembled battery 111. 123a is formed, and each contact surface 123a is in surface contact with each battery cell 113 individually. By adopting such a configuration, the relative movement of the adjacent battery cells 113 is prevented, the gap between the respective battery cells 113 is properly maintained, and a problem that may occur when the battery cells 113 move relatively, that is, the battery It is possible to prevent problems such as spot welding detachment with respect to the battery cell 113 of the conductive wire connecting the cells.

  By the way, in the configuration in which the rubber mat 121 is interposed between the assembled battery 111 and the battery case 103, an arrangement space having a predetermined size is set between the assembled battery 111 and the battery case 103 for use with the rubber mat. There may be variations in the dimensions of the arrangement space due to manufacturing errors of the battery case 103 or the rubber mat 121 and the battery cell 113. And, for example, when the arrangement space dimension varies, the rubber mat 121 is excessively compressed when the battery cover 105 is attached to the battery case 103, and on the other hand, the arrangement space varies. In some cases, a gap is generated between the rubber mat 121 and the battery case 103 or between the rubber mat 121 and the assembled battery 111, and as a result, the buffering function of the rubber mat 121 is impaired. The above arrangement space corresponds to the “buffer arrangement space” in the present invention.

  However, according to the present embodiment, the elastic constant of the lower surface side region 125 is provided by providing the recess 125a, the protrusion 125c, and the horizontal and vertical grooves 125d, 125e in the lower surface region 125 of the rubber mat 121 as described above. Is formed smaller than the elastic constant of the upper surface region 123. For this reason, when the assembled battery 111 is accommodated in the battery case 103 by setting the thickness of the rubber mat 121 to slightly exceed the tolerance of the arrangement space, the lower surface side region 125 of the rubber mat 121 is more than the upper surface side region 123. Also, it is possible to absorb the dimensional variation due to the above manufacturing error by being deformed (collapsed) first. As a result, the upper surface side region 123 of the rubber mat 121 is maintained in a state in which a predetermined elastic deformation is possible. For this reason, as a shock absorber against vibration generated when performing a machining operation using an electric tool, or an impact generated when the electric tool or the battery pack 101 is hit or dropped when the electric tool is carried. Thus, the original shock absorbing performance of the rubber mat 121 can be secured, and the assembled battery 111 can be protected from vibration and shock.

  In the present embodiment, a cylindrical protrusion 125c is formed in the lower surface side region 125 of the rubber mat 121, and a predetermined gap is provided between adjacent protrusions 125c. For this reason, the gap between the protrusions 125c can be used as a heat storage space for storing heat generated when the battery cell 113 is discharged (or charged).

  In the present embodiment, a plurality of ribs 103b are projected from the bottom surface 103a of the battery case 103 toward the assembled battery 111, and the ribs 103b are inserted into through holes 121a provided in the rubber mat 121 to thereby form the rubber mat. 121 is configured to prevent positional displacement. For this reason, it is possible to prevent the rubber mat 121 from moving due to vibrations or impacts acting on the battery pack 101 to prevent the rubber mat 121 from being crushed by misalignment, and to maintain the original buffer function of the rubber mat 121.

  In the above-described embodiment, the shape of the protrusion 125c formed in the lower surface region 125 of the rubber mat 121 is not limited to a columnar shape, and may be changed to a hemispherical shape, a prismatic shape, a cylindrical shape, or the like. Further, the protrusion 125c may be either a regular arrangement configuration or an irregular arrangement configuration. Further, as means for making the elastic constant of the lower surface side region 125 smaller than the elastic constant of the upper surface side region 123 of the rubber mat 121, the upper surface side region 123 and the lower surface side region 125 are formed of different elastic materials and joined together. You may change to

In view of the gist of the present invention, the following modes can be configured.
(Aspect 1)
“A battery pack for a hand-held power tool according to claim 1,
The second buffer region is provided on the side facing the wall surface of the container, and has a group of protrusions protruding toward the wall surface of the container. .

  According to the invention described in the aspect 1, the elastic constant relating to the second buffer region can be easily adjusted by the shape, number, or arrangement of the protrusions.

(Aspect 2)
“The battery pack for the hand-held power tool according to claim 3,
The engaging portion is constituted by a protrusion protruding from the wall surface of the container,
The engaging recess is constituted by a hole formed in the buffer,
A battery pack for an electric tool, wherein the protrusion is inserted into the hole to prevent displacement of the buffer body with respect to the container. "

  According to the invention described in the aspect 2, the misalignment preventing protrusion provided on the container can be used as a reinforcing member for reinforcing the container.

1 is a perspective view showing an overall configuration of a battery pack for a handheld power tool according to an embodiment of the present invention. It is sectional drawing which similarly shows the whole structure of the battery pack for handheld power tools. It is a perspective view which shows the structure of a rubber mat. It is a top view of a rubber mat. It is a front view of a rubber mat. It is a bottom view of a rubber mat. It is a side view of a rubber mat. It is sectional drawing which shows the fixing means of a rubber mat.

Explanation of symbols

101 Battery pack 103 Battery case (container)
103a Bottom (wall surface)
103b Rib (engagement part, protrusion)
105 battery cover 105a pressing member 111 assembled battery 113 battery cell 121 rubber mat (buffer body)
121a Through hole (engagement recess)
123 Upper surface side region (first buffer region)
123a Contact surface 125 Lower surface side region (second buffer region)
125a Concave portion 125b Convex portion 125c Projection 125d Horizontal groove 125e Vertical groove

Claims (3)

An assembled battery comprising a plurality of battery cells arranged in parallel to each other;
A container for housing the assembled battery;
A battery pack for a hand-held power tool having a shock absorber interposed between the container and the assembled battery in a state of being in contact with a wall surface of the container and a side surface of the assembled battery,
The buffer body has a first buffer region and a second buffer region each made of an elastic material in layers, and the elastic constant of the second buffer region is larger than the elastic constant of the first buffer region. It is set small,
When driving the electric tool using the battery pack, vibration transmitted from the electric tool to the battery pack, or when moving the electric tool by hand, the electric tool or the battery pack The first buffer region absorbs transmission of the impact acting on the assembled battery to the assembled battery,
The battery pack for a hand-held power tool, wherein the second buffer region absorbs the dimensional variation of the buffer arrangement space between the container and the assembled battery. The battery pack for a hand-held power tool according to claim 1,
The buffer body has a shape that corresponds to the shape of the side surface of each battery cell that constitutes the assembled battery on the side that contacts the side surface of the assembled battery, and is adjacent to each other by making surface contact with each battery cell individually. A battery pack for a hand-held power tool, wherein the battery cell is configured to restrict relative movement. The battery pack for a hand-held power tool according to claim 1 or 2,
An engagement part that protrudes toward the other side of the container and the buffer is formed on one side of the container and the buffer, and the engagement part is formed on the other side. An engagement recess that can be engaged with the container is provided, and the engagement portion engages with the engagement recess to prevent displacement of the buffer relative to the container. Battery pack for power tools.

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