JP2011009006A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack whose assembling workability is satisfactory, when assembling a secondary battery.SOLUTION: A battery core pack (2), that has a flat hexahedron, is accommodated in a battery pack case (1). The battery pack case (1) accommodates the battery core pack (2), and has integrally constructed four sidewalls located opposite to four side surfaces of the battery core pack (2). The battery pack case (1) is a box-formed housing having two main surfaces, one of which has an opening surface (1O), and the other has a bottom surface (1U). In one corner of the battery pack case (1) and an opening surface (1O) of the battery pack case (1), there are provided extending parts (3R), (3L) that extend toward the center of the opening surface (1O) from the corner, and further, on a side of the extending parts (3R), (3L) of at least one sidewall of the four sidewalls adjacent to the corner, there are provided notches (11CR), (11CL) and (14C) opened from the opening surface (1O).

Description

 The present invention accommodates a battery, such as a chargeable / dischargeable nonaqueous electrolyte secondary battery, mainly used as a power source of a portable electronic device such as a video camera, a mobile computer, a mobile phone, etc., and an exposed surface of the battery and the case The present invention relates to a battery pack configured by attaching a label to a part of the battery pack.

 As a power source for portable electronic devices such as video cameras, mobile computers, and mobile phones that have been rapidly spread in recent years, it has a cylindrical shape or a rectangular parallelepiped shape and can be charged / discharged, for example, a non-aqueous electrolyte such as a lithium ion secondary battery. Secondary batteries are mainly used. As an example of a lithium ion secondary battery (hereinafter referred to as a battery), an electrode group in which a positive electrode and a negative electrode are wound through a separator, and a nonaqueous electrolyte are housed in a rectangular parallelepiped case made of aluminum or an aluminum alloy. There is something configured as. On one side of the battery, a protection circuit for preventing overcharge and overdischarge, and a protection circuit board having an output terminal for taking out electric power from the battery or taking in electric power from the outside are arranged, and the battery core Is configured. The protective circuit board and the battery are electrically connected by connecting leads.

 A battery pack is obtained by covering the four side surfaces of the battery core with an insulating frame made of, for example, a synthetic resin, or by housing the battery core in a case made of, for example, a synthetic resin and opened on one side. .

 When using an exterior frame, both flat surfaces of the battery core and a part of the exterior frame are covered with a label. When the case is used, a battery pack is obtained by sticking a label on the exposed surface of the battery core, bending the end of the label, and sticking the label to the side plate of the case. For example, in Patent Document 1, in the battery storage chamber of a cylindrical battery, the first and second presses are arranged so as to press and hold the outer periphery toward the battery side on at least one side of the battery storage part. It has a member and is located at a predetermined interval so that the first pressing member is located on the battery contact spring member side. In the battery housing chamber, the second pressing member is configured by forming an inclined surface at an end portion on the first pressing member side. Thus, the 1st, 2nd press member which presses the side surface of a cylindrical battery is disclosed.

JP-A-8-879993

In the above-described cylindrical battery, the pressing portion is in contact with the battery side surface, and when the force that the cylindrical battery pops out in the opening direction of the battery storage chamber is applied, the cylindrical battery is securely held in the storage chamber by the pressing portion. Becomes difficult. Further, if the pressing part is further extended so as to cover the cylindrical battery more than shown, and the opening of the battery storage chamber is made smaller, the cylindrical battery becomes the pressing part when the cylindrical battery is attached to the battery storage part. There is a case where the contact and the pressing part and the cylindrical battery are broken or damaged.
In the case of a prismatic battery, the battery inserted into the case can be held by providing an extension from the corner of the battery case. However, when the case is inserted, there is a problem that the prismatic battery and the extending portion are in contact with each other, and a load (force) is applied to both.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a battery pack that has good assemblability when a secondary battery is assembled.

  In the present invention, a battery core pack 2 having a flat hexahedron appearance structure composed of two main surfaces and four side surfaces is housed in a battery pack case 1. The battery pack case 1 accommodates the battery core pack 2 and is integrally configured with four side walls facing each of the four side surfaces of the battery core pack 2. The battery pack case 1 is a box-shaped casing having an opening surface 1O on the other one of the two main surfaces and a bottom surface 1U on the other surface. The battery pack case 1 includes extending portions 3R and 3L extending from the corner toward the center of the opening surface 1O at one corner of the opening surface 1O of the battery pack case 1 and adjacent to the corner. It is characterized by having notches 11CR, 11CL, and 14C opened from the opening surface 1O on the extended portions 3R and 3L side of at least one of the four side walls.

  And the battery pack of Claim 2 of this invention is equipped with the said notches 11CL and 14C in the two said side walls adjacent to the said corner | angular part.

  The battery pack according to claim 3 of the present invention is characterized in that, in one of the side walls, the notches 11CR and 11CL are provided on the extending portions 3R and 3L extending from the corner portions located at both ends. To do.

In the battery pack of the present invention, when the battery core pack is inserted into the battery pack case, the extension portion and the battery core pack come into contact with each other to reduce the load on the extension portion and the battery core pack. By having a notch opened from the opening surface on the side wall on the extension part side of the pack case, the side wall of the battery pack case has a shape capable of elastic deformation.
That is, when the battery core pack is inserted, the fourth side wall notch and the first side wall notch cause the side wall extending from the extending portion 3 to open outwardly flexibly due to elastic deformation. The battery core pack can be inserted into and held in the battery pack case while reducing the load (force) caused by the battery core pack and the extension portion coming into contact with each other without applying excessive force to the protruding portion. Can do.

  According to the second aspect of the present invention, since the two side walls adjacent to the corner are provided with the notches, the extended portion of the corner can be deformed and displaced with a smaller force. Therefore, the battery core pack can be easily inserted into the battery pack case.

  Further, according to the third aspect, since one of the side walls is provided with a notch on the extending part side extending from the corners located at both ends, the side wall is provided with a notch on both sides. Therefore, the side wall and the both extending portions can be deformed and displaced with a smaller force. Therefore, the battery core pack can be easily inserted into the battery pack case.

It is a perspective view which shows the battery pack of this invention. It is a perspective view of the battery pack case of this invention. It is the perspective view which looked at FIG. 2 from the 3rd side wall side. It is the perspective view which looked at FIG. 1 from the 1st side wall side. It is a disassembled perspective view of the battery pack of this invention. It is the perspective view which showed the method of mounting | wearing a battery pack case with a battery core pack. The figure which looked at the label affixed on the battery pack of this invention from the upper surface. It is a figure which shows the process of affixing a label on the battery pack of this invention, and the state by which the label was affixed on the battery pack, (A) is the figure which showed the process 1 which affixes a label on a battery pack from the upper surface. Yes, (B) is a view showing Step 2 of attaching the label to the battery pack from the side, and (C) is a six-sided view of the state where the label is attached to the battery pack. , (A) is a plan view, (b), (c), (d) and (e) are side views, and (f) is a bottom view.

  Embodiments of the present invention will be described below with reference to the drawings. However, the example shown below illustrates the 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.

  The battery pack of the present invention is mainly mounted on a portable device and supplies power to the device body. In particular, the present invention has an optimum structure as a battery pack that can be safely used in a small portable device. Moreover, the load at the time of inserting a battery core case in the battery pack case 1 of this invention in the manufacturing process is reduced. Hereinafter, although the battery pack used for a small portable apparatus is explained in full detail as an Example, this invention does not specify the use of a battery pack. The directions shown in the figure are the X-axis, Y-axis, and Z-axis directions.

  The unit cell 4 of the battery core pack 2 having a flat hexahedron external structure composed of two main surfaces and four side surfaces housed in the battery pack case 1 has, for example, a rectangular flat plate shape (substantially rectangular parallelepiped external shape). A nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, for example, an electrode group in which a positive electrode and a negative electrode are wound via a separator, and a nonaqueous electrolyte (not shown) made of aluminum or an aluminum alloy Contained in a case. A negative electrode terminal (not shown) is provided on one end surface 44 of the unit cell 4 in an insulated state with respect to the one end surface 44, and a lead mounting plate 4L1 is provided on one end surface 42 opposite to the negative electrode terminal. The entire unit cell 4 other than the portion provided with the negative electrode terminal becomes a positive electrode (terminal). The surface of the unit cell 4 other than both end faces of the unit cell 4 provided with the negative electrode terminal and the lead plate 4L mounting part is insulated from the outside by the battery pack case 1 and the label L being pasted. As shown in FIG. 5, the side surfaces 41 and 43 in the extending direction of the unit cell 4 have a curved cross-sectional shape (arc shape).

  FIG. 2 is a perspective view showing the battery pack case 1. The battery pack case 1 is made of a plastic material. Of the two main surfaces of the battery pack case 1, one surface has an opening surface 1O, the other surface has a bottom surface 1U, and four side surfaces of the battery core pack 2 to be stored. This is a box-shaped housing in which the four side walls 11, 12, 13, and 14 in a state of facing each of 21, 22, 23, and 24 are integrally formed (appearance shape of a substantially rectangular parallelepiped shape). Here, “the four side walls are integrally configured” means that at least the four side walls are connected when the unit cell is inserted (attached), and injection molding or the like is used. Including the case where the four side walls are integrally molded or the case where a plurality of parts are joined in advance.

As shown in FIG. 2, the opening surface 1O of the battery pack case 1 opens the entire one main surface of the battery pack case 1, and the opening surface 1O is opened vertically in the Z-axis direction.
The bottom surface 1U has a substantially rectangular bottom opening surface 1UO, and the upper and lower sides in the Z-axis direction are opened. The second side wall 12 and the fourth side wall 14 are opposite side surfaces, and have substantially the same shape in a side view from the Y-axis direction. In the side view of the second side wall 12 and the fourth side wall 14 from the Y-axis direction, the end portions of the second side wall 12 and the fourth side wall 14 on the first side wall 11 side extend in the extending direction of the battery core pack 2 to be inserted. It is gently curved from the opening surface 1O side so as to face the arc shape of the side surface 21, and has an arc shape.

  In the first side wall 11 of the battery pack case 1, the side surface 21 in the extending direction of the battery core pack 2 is stored facing the first side wall 11. The extending direction side surface 21 has an arc shape. Therefore, the extending side surface 21 is stored oppositely, and the first side wall 11 disposed is also gently curved from the opening surface 1O side, and has an arcuate shape protruding toward the extending direction side surface 21 side. With this shape, the extending side surface 21 is pressed and held by the first side wall 11.

  That is, the first side wall 11 side of the battery pack case 1, the first side wall 11 side end of the second side wall 12, and the first side wall 11 side end of the fourth side wall 14 are circles on the side surface 21 in the extending direction of the battery core pack 2. By matching the arc shape, when the second wall side 12, the fourth side wall 14, and the side surface 21 in the extending direction of the battery core pack 2 are stored facing each other, a gap and an extra space are eliminated, and more stably. The battery core pack is configured to be accommodated in a battery case.

  A plurality of reinforcing ribs 11R are integrally provided at the connecting portion between the first side wall 11 and the bottom surface 1U so as to be associated with both the first wall side 11 and the bottom surface 1U. The third side wall 13 includes a single terminal window 13O at the center. By this terminal window 13O, the connection terminal 4TL of the protection circuit board 4T can be exposed. In addition, the third side wall 13 has a shape in which an eaves portion 13H that extends from the side of the opening surface 1O in the same plane as the opening surface 1O is integrally formed. The eaves portion 13H extends to both sides and has a shape integrally formed continuously with the end portion on the third side wall 13 side on the opening surface 1O side of the second side wall 12 and the fourth side wall 14. The third side wall 13 is stored facing the extending side surface 23 of the battery core pack 2. The eaves portion 13 </ b> H can contact the main surface of the battery core pack 2 housed in the battery pack case 1 on the side of the opening surface 1 </ b> O and hold the battery core pack 2. With such a configuration, the battery core pack 2 is housed and held in the battery pack case 1 with stability and certainty.

  As shown in FIG. 2, of the two main surfaces of the battery pack case 1, one surface is provided with an opening surface 1O opened up and down in the Z-axis direction, and the other surface is a box-shaped housing provided with a bottom surface 1U. is there. At one corner of the opening surface 1O of the battery pack case 1, there are provided extending portions 3R and 3L extending from the corner toward the center of the opening surface 1O. In FIG. 2, the extension 3 </ b> R extends from the corner on the opening surface 1 </ b> O side of the first side wall 11 and the second side wall 12 as one corner, and the first side wall 11 and the fourth side as one corner. An extension 3L extends from a corner of the side wall 14 on the opening surface 1O side.

  As shown in FIG. 2, the extension part end surface 3DR is on the extension of the first side wall notch end surface 11CDR, and is integrally formed and connected to the first side wall notch end surface 11CDR. Similarly, the extension portion end surface 3DL is on the extension of the first side wall notch end surface 11CDL, and is integrally formed with and connected to the first side wall notch end surface 11CDL. Since the extending portion 3R extends from the corner toward the center of the opening surface 1O, the extending portion end surface 3DR is coupled to the end portion on the opening surface 1O side opposite to the X-axis direction of the second side wall 12. . That is, the extension part end surface 3DR extends from the end part on the opening surface 1O side opposite to the X-axis direction in the second side wall 12, and is integrally formed.

  Since the extending portion 3L extends from the corner toward the center of the opening surface 1O, the extending portion end surface 3DL is coupled to the end portion on the opening surface 1O side opposite to the X-axis direction in the fourth side wall 14. . That is, the extension part end surface 3DL extends from the end part on the opening surface 1O side opposite to the X axis direction on the fourth side wall 14, and is integrally formed.

That is, the extension portion end surfaces 3DR and 3DL are connected to the first side wall notch end surfaces 11CDR and 11CDL, and the extension portion end surfaces 3DR and 3DL are side surfaces of the second side wall 12 and the fourth side wall 14, respectively. It becomes substantially the same shape as the curved shape in view.
Further, regarding the thicknesses of the extension portions 3R and 3L, the extension portion end surfaces 3DR and 3DL are on the extension of the first side wall notch end surfaces 11CDR and 11CDL, and are integrated with the first side wall notch end surfaces 11CDR and 11CDL. By being formed and connected, the thickness of the first side wall 11 is necessarily substantially equal. Further, as shown in FIG. 8, the extending portions 3R and 3L are substantially rectangular in top view.

  At least one of the first side wall 11, the second side wall 12, and the fourth side wall 14, which has two corners extending from the extension parts 3 </ b> R, 3 </ b> L, as the side wall, has an opening surface on the extension part 3 </ b> R, 3 </ b> L side. A notch opened from 1O is provided. In the embodiment, the first side wall 11 is provided with first side wall notches 11CR and 11CL, and the fourth side wall 14 is provided with a fourth side wall notch 14C.

  The first side wall cutouts 11CR and 11CL are provided in the shape of a cutout having a substantially rectangular opening from the opening surface 1O side at the end of the first side wall 11. The depth and width of the concave portions of the first side wall notches 11CR and 11CL are appropriately designed in consideration of the desired deformation of the side wall made of resin used for the battery case pack. At this time, if the recesses of the first side wall notches 11CR and 11CL are too deep, the strength of the first side wall 11 is reduced. Further, if the depth is shallow, the deformable distance or width (elastic amount) of the first side wall 11 is reduced, and when the battery core pack 2 is inserted into the battery case pack, the side surfaces of the battery core pack 2 extending in the two extending directions. 21 abuts against the first side wall 11 and a load (more than desired force) is applied to the first side wall 11, making it difficult to insert, and the effect of reducing the load (force) during insertion cannot be obtained. In the first side wall 11, there are extension part end surfaces 3DR, 3DL of the extension parts 3R, 3L on the extension of the first side wall notch end faces 11DR, 11DL forming the notches 11CR, 11CL. It has a continuously integrated shape. In addition, unlike the above-mentioned, the shape which does not have extension part end surface 3DR, 3DL on the extension of the side wall which forms 1st side wall notch 11CR, 11CL may be sufficient.

  That is, in FIG. 2, the extending portions 3R and 3L extend from the opening surface 1O side of the second wall side 12 and the fourth side wall 14 on the opposite side in the X-axis direction to the same plane as the opening surface 1O. Yes. As shown in FIGS. 2 and 7, the extension portions 3 </ b> R and 3 </ b> L have a rectangular shape when viewed from the upper surface, and are plate bodies. Further, one long side of the extending portions 3R and 3L is integrated with the fourth side wall 14 or the second side wall 12. One short side of the extending portion is provided integrally with the first side wall 11.

  Further, as shown in FIG. 3, the fourth side wall 14 has a rectangular fourth side wall notch 14C in the vicinity of the extending portion 3L. The fourth side wall notch 14C is provided with a notch from the opening surface 1O. Similar to the first side wall notches 11CR and 11CL, the fourth side wall notch 14C adjusts the distance or width (elastic deformation amount) that can be deformed by its depth. can do.

  As shown in FIG. 5, the battery core pack 2 has a structure in which a protection circuit board 4 </ b> T is installed via a board holder 4 </ b> H in a state along the side surface 43 in the extending direction of the unit cell 4. The length of the substrate holder 4H is the same as the length of the side surface 43 in the extending direction of the unit cell 4 to be arranged, and the thickness (height) of the substrate holder 4H is equal to the thickness of the unit cell 4. . The substrate holder 4H is provided with a substrate and a lead plate storage portion on the opposite surface where the unit cell 4 is installed. By storing the protection circuit board 4T in the board holder 4H, the protection circuit board 4T is reliably positioned and held. A lead plate 4L and a lead plate 4P with PTC connected to the protection circuit board 4T are arranged between the protection circuit board 4T and the board holder 4H, and are held between the protection circuit board 4T and the board holder 4H. . One end portion of the lead plate 4P with PTC bent in an L shape is connected to the protection circuit board 4T, and the other end portion is connected to the negative electrode terminal of the unit cell 4. The L-shaped lead plate 4L has one end connected to the protection circuit board 4T and the other end connected to the negative terminal (not shown) of the unit cell 4.

A method of storing and arranging the battery core pack 2 in the battery pack case 1 is illustrated in FIG. First, as shown by the arrow, the extending side surface 23 in which the protection circuit board 4T is arranged in the battery core pack 2 via the board holder 4H is housed inside the battery pack case 1 on the third side wall 13 side. . At this time, the protection circuit board 4T, the lead plate 4L, the lead plate 4P with PTC, and the like, which are mounting components of the battery core pack 2, are carefully stored so as not to apply stress.
Thereafter, since the first side wall 11 has an arc shape protruding toward the extending side surface 21, the extending side surface 21 of the battery core pack 2 is located on the upper end of the first side wall 11 of the battery pack case 1. The first side wall 11 is abutted and stored while being deformed outward. The core pack one end portion 22 and the core pack other end portion 24 (the core pack one end portion 22 and the core pack other end portion 24) of the battery core pack 2 are the extension portion end surfaces 3DR and 3DL of the two extension portions 3R and 3L of the battery case. The first side wall notch 11CR, 11CL, 14C causes the first side wall 11, the second side wall 12, and the fourth side wall 14 to be elastically deformed by abutting on the (thickness direction surface), and the extension 3R is the second The extending part 3L is housed while being moved to the outside of the fourth side wall 14 outside the side wall 12. That is, the first side wall cutouts 11CR and 11CL and the fourth side wall cutout 14C facilitate the movement and deformation of the extending portions 3R and 3L to the outside of the fourth side wall 14 and the outside of the second side wall 12, respectively. ing.
Further, the first side wall notches 11CR and 11CL make it easy for the extending side surface 21 of the battery core pack 2 to abut on the upper end of the first side wall to deform the first side wall 11 outward.

  Particularly, at this time, the side wall (first side wall 11 and fourth side wall 14) in the vicinity of the fourth side wall notch 14C is elastically deformed, so that the second side wall 12 and the fourth side wall 14 of the battery pack case 1 are connected to the battery pack. The load (force) that deforms to the outside of the case 1 is reduced. Although not shown in the embodiment, the second side wall 12 may have a notch similar to the fourth side wall 14.

  As shown in FIG. 1, the battery core pack 2 is stored in the battery pack case 1. As shown in the drawing, when the storage is completed, the upper surface of the battery core pack 2 is located under both the extension portions 3, so that the battery core pack 2 is pulled out of the battery pack case 1 due to an impact or the like. , Can be reduced. Similarly, the first side wall 11 protrudes toward the extending direction side surface 21 side that is gently curved from the opening surface 1O side so as to follow the arc on the extending direction side surface 21 of the battery core pack 2 to be inserted. It has a circular arc shape. With this shape, the extending side surface 21 is pressed and held by the first side wall 11, and it is possible to reduce the battery core pack 2 from coming out of the battery pack case 1 due to an impact or the like.

The battery pack 5 is a state in which the battery core pack 2 is stored in the battery pack case 1.
As shown in FIGS. 1 and 4, the battery pack 5 has a flat hexahedron appearance structure composed of two main surfaces and four side surfaces, and the battery pack 5 has an opening surface 1O and a bottom opening surface 1UO. The two main surfaces of the core pack 2 are exposed. Therefore, the T-shaped label L prevents the two main surfaces of the battery core pack 2 from being exposed, and improves the insulation between the battery core pack 2 and the outside. The label L is made of a flexible plastic sheet and has an adhesive applied on one side.

  As shown in FIG. 7, the label L has a T-shape, and the width of the label vertical line portion LT on the T-shape of the label L is the horizontal width (battery pack case) of the battery pack 5 in FIG. 1 first side wall 11 and third side wall 13). The width of the T-shaped label horizontal line portion LY of the label L is approximately the same as the vertical width of the battery pack 5 (second side wall 12 and fourth side wall 14 of the battery pack case 1). And as process 1, as shown in Drawing 8 (A), it arranges so that the center of battery pack 5 may be located in the center of T-shaped label horizontal line part LY of label L. Furthermore, it arrange | positions so that the 3rd side wall 13 and the label horizontal line part LY may become horizontal. Next, as step 2, the label horizontal line portion LY is attached to the main surface of the battery pack 5 in the direction indicated by the arrow in FIG. 8B so as to relate to the second side wall 12 and the fourth side wall 14. Thereafter, the label vertical line LT is attached to the main surface of the battery core pack 5 so as to be related to the first side wall 11. In addition, a label notch LC is provided in the label vertical line portion LT, and the label notch LC exposes a part of the first side wall 11 so that the battery core pack 5 to which the label L is attached is attached. When handling, it has the effect of anti-slip function.

DESCRIPTION OF SYMBOLS 1 Battery pack case 1O Opening surface 1U Bottom surface 1UO Bottom opening surface 11 1st side wall 11CR 1st side wall notch 11CL 1st side wall notch 11CDR 1st side wall notch end surface 11CDL 1st side wall notch end surface 11R Reinforcement rib 12 2nd side wall 13 3rd side wall 13O terminal window 13H eaves part 14 4th side wall 14C 4th side wall notch 2 battery core pack 21 extension direction side surface 22 core pack one end part (side surface)
23 Side surface in the extending direction 24 Core pack other end (side surface)
3R extension part 3L extension part 3DR extension part end face 3DL extension part end face 4 unit cell 41 unit cell extension direction side face 42 unit cell end face 43 unit cell extension direction side face 44 unit cell end face 4T protection circuit board 4TL connection terminal 4H PCB holder 4L Lead plate
4L1 Lead mounting plate 4P Lead plate with PTC 5 Battery pack L Label LY Label horizontal line part LT Label vertical line part LC Label notch

Claims (3)

A battery core pack (2) having a flat hexahedron appearance structure composed of two main surfaces and four side surfaces, and housing the battery core pack (2) and facing each of the four side surfaces of the battery core pack (2) A battery pack having a battery pack case (1) in which four side walls in a state of being integrally formed are configured,
The battery pack case (1) is a box-shaped housing in which one of the two main surfaces of the battery pack case (1) has an opening surface (1O) and the other surface has a bottom surface. The corner portion of the opening surface (1O) of the battery pack case (1) includes an extending portion (3R, 3L) extending from the corner portion toward the center of the opening surface (1O), and adjacent to the corner portion. At least one of the side walls has a notch (11CR), (11CL), and (14C) opened from the opening surface (1O) on the extending part (3R) and (3L) side. Battery pack.   The battery pack according to claim 1, wherein the notches (11CL) and (14C) are provided in the two side walls adjacent to the corner portion.   The said notch (11CR), (11CL) is provided in the extension part (3R, 3L) side extended from the said corner | angular part located in both ends in one of the said side walls, The Claim 2 characterized by the above-mentioned. Battery pack.

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