JP4401163B2 - battery pack - Google Patents

Description

  The present invention relates to a battery pack covering a thin battery with a plastic case connected by ultrasonic welding.

Battery packs that cover thin batteries with plastic cases have been developed. This battery pack accommodates a thin battery in a plastic case formed by dividing into two. The battery pack having this structure is manufactured by placing a thin battery in one case and then ultrasonically welding the peripheral wall. A battery pack having this structure is described in Japanese Patent Application Laid-Open No. 2005-268381.
JP 2003-68255 A

  This publication describes the battery pack shown in FIG. 1 as a conventional technique. Since the battery pack 1 houses the thin battery in a case having a closed structure, both surfaces of the thin battery are covered with a surface plate, and the outer peripheral surfaces of the four sides of the thin battery are covered with a peripheral wall. For this reason, the outer shape of the battery pack is larger than that of the thin battery, and the thickness is also thicker than that of the thin battery. In the battery pack having this structure, the outer surface plate of the case can be opened and thinned, and the outer wall can be reduced by thinning the peripheral wall. However, there is a drawback that the strength becomes weaker if the peripheral wall is made thinner. Furthermore, without providing a peripheral wall on the outer periphery of the four sides of the thin battery, the width of the battery pack can be reduced by omitting the peripheral wall on one side. However, if the surface plate is greatly opened and the peripheral wall has three sides, the case becomes U-shaped and the strength is significantly reduced.

  The present invention has been developed for the purpose of providing a battery pack capable of having a compact outer shape equivalent to that in which one side of the peripheral wall is omitted while effectively preventing a reduction in the strength of the case.

A battery pack 1 according to the present invention has a thin battery 2 having a thickness and an overall shape of a quadrangle as viewed from above and curved sides, and a peripheral wall 3 formed in a shape along the outer periphery of the thin battery 2. A plastic case 4 and a label 5 attached to the surface of the case 4 are provided. The peripheral wall 3 of the case 4 includes a first peripheral wall 3A and a second peripheral wall 3B that are divided on both surfaces of the thin battery 2. The first peripheral wall 3A and the second peripheral wall 3B are one unconnected peripheral wall 3a disposed outside the curved side surface 2A on one side of the thin battery 2, and three connected peripheral walls 3b excluding the non-connected peripheral wall 3a. It is formed in a frame shape along the outer periphery of the thin battery 2. The non-connected peripheral wall 3a is formed in a shape that is curved along the curved side surface 2A of the thin battery 2 and separates the opposed tip edges in a non-contact state. Further, the non-connected peripheral wall 3a and the second peripheral wall 3B are not connected. The connecting peripheral wall 3a is connected with a label 5 attached to the outside. The connecting peripheral wall 3b has the curvature radius of the outer corner 12 set to be smaller than that of the curved surface outside the non-connecting peripheral wall 3a, and the opposite end edges of the first peripheral wall 3A and the second peripheral wall 3B are ultrasonically welded to each other. ing.

  In the battery pack 1 according to the second aspect of the present invention, the outer peripheral cover portions 6 that cover the outer peripheral edge portions of both surfaces of the thin battery 2 are integrally formed on both sides of the peripheral wall 3. The radius of curvature of the outer corner 12 of the connecting peripheral wall 3b formed at the boundary between the outer peripheral cover 6 and the peripheral wall 3 is smaller than the radius of curvature outside the non-connecting peripheral wall 3a.

  In the battery pack 1 according to claim 3 of the present invention, a step surface 4A is provided on the surface of the outer peripheral cover portion 6 so as to lower the portion to which the label 5 is attached, and the label 5 is attached to the step surface 4A. .

  Furthermore, in the battery pack 1 of claim 4 of the present invention, the circuit board 8 that fixes the output terminal 7 is disposed between the connecting peripheral wall 3 b and the thin battery 2. In the battery pack 1, the substrate holder 9 is disposed between the connecting peripheral wall 3 b and the thin battery 2, and the circuit board 8 can be disposed at a fixed position via the substrate holder 9.

  The battery pack of the present invention has a feature that the outer shape can be reduced while preventing the strength of the case from being lowered. That is, the case is divided into both sides of the thin battery, and the peripheral wall that covers the outer peripheral surface of the four sides of the thin battery is composed of three connected peripheral walls and one non-connected peripheral wall. Ultrasonic welded and firmly connected, but the non-connected peripheral walls on one side have a structure that does not cover the entire curved side surface of the thin battery by separating the tip edges from each other as a structure that is not connected to each other. This is because the label is attached to connect the separated unconnected peripheral walls.

  In the battery pack having this structure, the non-connected peripheral walls of the peripheral walls are separated from each other without being connected to each other. Therefore, the battery pack can be made compact with the same external shape as a single peripheral wall is omitted. In addition, the non-connected peripheral wall that is not connected has a shape along the curved side surface of the thin battery, and the label is attached to the outer side of the thin battery to connect the thin peripheral battery. And the case can be made into an integral structure that is not separated.

  In addition, since the unconnected peripheral wall is not connected by the curved side surface of the thin battery, the width thereof is the same as that without the peripheral wall on one side, but the tip of the U-shaped connected peripheral wall is connected by the unconnected peripheral wall. Therefore, it is set as the structure which mutually connected the end with the connection surrounding wall and the non-connection surrounding wall. For this reason, the end of the U-shaped connecting peripheral wall does not open, the end of the connecting peripheral wall is connected by the non-connecting peripheral wall, and the non-connecting peripheral walls that are separated from each other are connected by the label, so that the strength of the peripheral wall can be increased. .

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below exemplifies a battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  A battery pack 1 shown in FIGS. 1 to 10 includes a thin battery 2, a plastic case 4 having a peripheral wall 3 formed in a shape along the outer periphery of the thin battery 2, and a label attached to the surface of the case 4. 5.

  As shown in FIG. 5, the thin battery 2 has a rectangular shape as a whole, and both side surfaces thereof are curved side surfaces 2A as shown in FIG. The thin battery 2 has curved side surfaces 2A on both sides of the end surface on which the convex electrode 2B is provided. The thin battery 2 is a lithium ion secondary battery. However, the battery pack of the present invention does not specify a thin battery as a lithium ion secondary battery. All secondary batteries such as nickel metal hydride batteries and nickel cadmium batteries can be used as thin batteries.

  As shown in FIGS. 1, 2, and 4, the peripheral wall 3 of the case 4 is divided into a first peripheral wall 3A and a second peripheral wall 3B so as to be separated into both surfaces of the thin battery 2. In FIG. 4, the peripheral wall 3 is divided into a lower first peripheral wall 3A and an upper second peripheral wall 3B. As shown in FIGS. 7 to 10, the first peripheral wall 3 </ b> A and the second peripheral wall 3 </ b> B integrally form an outer peripheral cover portion 6 that covers the outer peripheral edge portions of both surfaces of the thin battery. The case 4 of this shape has a feature that the battery pack 1 can be made particularly thin because the portion excluding the outer peripheral edge of the thin battery 2 is exposed to the outside and the surface of the thin battery 2 is covered with the label 5. However, although not shown, the battery pack of the present invention can also be formed by integrally forming a surface plate covering the entire surface of both surfaces of the thin battery on the peripheral wall.

  As shown in FIG. 5, the peripheral wall 3 is formed by connecting a non-connected peripheral wall 3 a on one side and a connected peripheral wall 3 b on three sides at a right angle to form a square shape as a whole. The unconnected peripheral wall 3a is disposed outside the curved side surface 2A on one side of the thin battery 2, as shown in FIGS. The peripheral wall 3 is formed into a frame shape along the outer periphery of the thin battery 2 by one non-connected peripheral wall 3 a and three connected peripheral walls 3 b. The unconnected peripheral wall 3a connects the tips of the connected peripheral walls 3b formed in a U-shape, and the peripheral wall 3 is formed into a rectangular frame shape by the unconnected peripheral wall 3a and the connected peripheral wall 3b.

  As shown in the enlarged cross-sectional view of FIG. 8, the non-connected peripheral wall 3a is formed into a shape that curves along the curved side surface 2A of the thin battery 2, and further, the opposed front end edges are separated in a non-contact state. The non-connected peripheral wall 3a has an inner surface curved in a shape along the curved side surface 2A of the thin battery 2, and an outer surface also curved in a shape along the curved side surface 2A. The curved unconnected peripheral wall 3 a is integrally formed of plastic so as to be connected to the outer peripheral cover portion 6 that covers the surface of the thin battery 2.

  8 is separated from the curved side surface 2A of the thin battery 2 by a width that does not protrude in the width direction. In the illustrated unconnected peripheral wall 3a, the protruding portion of the curved side surface 2A of the thin battery 2 and the outer side of the leading edge of the unconnected peripheral wall 3a are flush with each other. Therefore, the label 5 attached to the surface of the unconnected peripheral wall 3a is attached in a planar manner to the leading edge of the non-connected peripheral wall 3a and the protruding portion of the curved side surface 2A of the thin battery 2. As shown in the figure, the protruding portion of the curved side surface 2A of the thin battery 2 is flush with the outer surface of the unconnected peripheral wall 3a, or although not shown, the protruding portion of the curved side surface protrudes from the outer surface of the unconnected peripheral wall. The battery pack to be attached can attach the label 5 to the curved side surface 2A of the thin battery 2 at the separated boundary of the non-connected peripheral wall 3a. In this structure, since the label 5 is attached to both the surface of the non-connected peripheral wall 3a and the curved side surface 2A of the thin battery 2, the label 5 firmly connects the non-connected peripheral wall 3a and the thin battery 2. The battery pack 1 can be provided with the thickest unconnected peripheral wall 3a without increasing the overall width (W). However, the battery pack of the present invention may have a structure in which the curved side surface of the thin battery does not protrude from the outside of the non-connected peripheral wall.

  The connecting peripheral wall 3b has a radius of curvature of the outer corner 12 formed at the boundary with the outer peripheral cover portion 6 as a radius of curvature smaller than the curved surface outside the non-connecting peripheral wall 3a, and the leading edges of the first peripheral wall 3A and the second peripheral wall 3B that face each other. Are connected to each other by ultrasonic welding. The connecting peripheral wall 3b having a small curvature radius of the outer corner 12 is sandwiched between the ultrasonic horn and the base and pressed as shown by the arrows in FIGS. Can be welded.

  In the illustrated battery pack 1, a circuit board 8 that fixes an output terminal 7 is disposed between the connecting peripheral wall 3 b and the thin battery 2. Further, in order to place the circuit board 8 at a fixed position, a board holder 9 is arranged between the connecting peripheral wall 3b and the thin battery 2 and the circuit board 8 is arranged at an accurate position by the board holder 9. Yes. As shown in the cross-sectional view of FIG. 9, the substrate holder 9 has an inner surface formed into a shape along the curved side surface 2 </ b> A of the thin battery 2. Further, on the outer surface, opposed walls 10 are provided on both sides to support the circuit board 8 and to be disposed at a fixed position. The facing wall 10 contains an electronic component 11 mounted on the circuit board 8 inside.

  In the illustrated battery pack 1, the curved side surface 2A of the thin battery 2 is disposed at the center of the U-shaped connecting peripheral wall 3b, and the circuit board 8 is disposed here. The circuit board 8 is connected to the thin battery 2 by connecting a lead plate connected to the convex electrode 2B and a lead plate connected to the opposite surface of the convex electrode 2B. The output terminal 7 fixed to the circuit board 8 is exposed to the outside from a terminal window 13 provided on the connection peripheral wall 3b. The electronic component 11 mounted on the circuit board 8 realizes a protection circuit for the thin battery 2.

  The label 5 is a plastic sheet having an adhesive layer on the back surface, and is attached via the adhesive layer. The battery pack 1 shown in FIGS. 2, 9, and 10 is provided with a step surface 4A that lowers the portion to which the label 5 is attached on the surface to which the label 5 is attached. The label 5 is inserted into the step surface 4A. Are attached. In the battery pack 1 of FIGS. 1 and 2, the label 5 is attached from the surface of the outer peripheral cover portion 6 of the connecting peripheral wall 3b to the surface of the non-connecting peripheral wall 3a. The label 5 is attached to the surface of the outer peripheral cover portion 6 of the connection peripheral wall 3b so as to be folded back at the non-connection peripheral wall 3a. Furthermore, since the surface of the thin battery 2 is exposed inside the outer peripheral cover portion 6, the label 5 is also attached to the surface of the thin battery 2. This label 5 is attached to the surface of the non-connected peripheral wall 3a, connects the non-contact peripheral wall 3a of the first peripheral wall 3A and the second peripheral wall 3B that are separated in a non-contact state, and further the outer peripheral cover portion 6 of the connection peripheral wall 3b. And attached to the thin battery 2 to connect them.

The perspective view which shows the battery pack of one Example of this invention. The perspective view which shows the state which is the battery pack shown in FIG. 1, and does not adhere a label. Side view of the battery pack shown in FIG. End view of the battery pack shown in FIG. Horizontal sectional view of the battery pack shown in FIG. 1 is a vertical cross-sectional view of the battery pack shown in FIG. Vertical sectional view of the battery pack shown in FIG. The principal part expanded sectional view of FIG. The principal part expanded sectional view of FIG. 7 is an enlarged cross-sectional view of the main part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery pack 2 ... Thin battery 2A ... Curved side surface 2B ... Convex part electrode 3 ... Perimeter wall 3A ... 1st surrounding wall 3B ... 2nd surrounding wall
3a ... Non-connection peripheral wall 3b ... Connection peripheral wall 4 ... Case 4A ... Step surface 5 ... Label 6 ... Outer cover part 7 ... Output terminal 8 ... Circuit board 9 ... Substrate holder 10 ... Opposite wall 11 ... Electronic component 12 ... Outer corner 13 ... Terminal window

Claims (5)

A thin battery (2) having a thickness and an overall shape that is square when viewed from above and having curved surfaces on both sides, and a peripheral wall (3) formed into a shape along the outer periphery of the thin battery (2) A battery pack comprising a plastic case (4) and a label (5) attached to the surface of the case (4),
The peripheral wall (3) of the case (4) is composed of a first peripheral wall (3A) and a second peripheral wall (3B) which are divided on both sides of the thin battery (2), and the first peripheral wall (3A) and the second peripheral wall ( 3B) is a non-connected peripheral wall (3a) disposed outside the curved side surface (2A) of one side of the thin battery (2), and a three-side connected peripheral wall (3b) excluding the non-connected peripheral wall (3a). And formed into a frame shape along the outer periphery of the thin battery (2),
The unconnected peripheral wall (3a) is formed into a shape that curves along the curved side surface (2A) of the thin battery (2),
The opposite end edges are separated from each other in a non-contact state, and the unconnected peripheral wall (3a) of the first peripheral wall (3A) and the second peripheral wall (3B) is connected with a label (5) attached to the outside. And
The connecting peripheral wall (3b) has opposite radii of the first peripheral wall (3A) and the second peripheral wall (3B) with the radius of curvature of the outer corner (12) being smaller than that of the curved surface outside the non-connecting peripheral wall (3a). A battery pack in which the edges are joined together by ultrasonic welding.   The case (4) has a thin battery (2) and an outer peripheral cover portion (6) that covers the outer peripheral edge portions of both surfaces formed integrally on both sides of the peripheral wall (3). The battery according to claim 1, wherein a radius of curvature of the outer corner (12) of the connecting peripheral wall (3b) formed at a boundary with the peripheral wall (3) is smaller than a radius of curvature of the outer side of the non-connecting peripheral wall (3a). pack. A step surface (4A) is provided on the surface of the outer peripheral cover portion (6) to lower the portion to which the label (5) is attached, and the label (5) is attached to the step surface (4A). Item 5. The battery pack according to item 2. The battery pack according to claim 1, wherein a circuit board (8) fixing the output terminal (7) is disposed between the connecting peripheral wall (3b) and the thin battery (2).   A substrate holder (9) is arranged between the connecting peripheral wall (3b) and the thin battery (2), and the circuit board (8) is arranged at a fixed position via the substrate holder (9). The battery pack according to claim 4.

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