JP2011171125A - Battery pack and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a lead plate in a perpendicular attitude without fail when the lead plate is spot-welded to a unit cell. <P>SOLUTION: A battery pack includes a pair of metal lead plates 30 having flexibility which are respectively welded to end surface electrodes 11 on both the sides of a battery block 1 which is a laminate of the unit cell 10 held by a battery holder 20 to electrically connect adjoining unit cell 10. In the battery holder 20, an end part locking part 26 which is so opened as to hold one end of the lead plate 30, and an intermediate locking part 28 which is so opened as to hold a part of midpoint in the lamination direction of the plurality of unit cells 10 out of the lead plates 30, are formed. The lead plates 30 form a lead intermediate locking region 34 held to the intermediate locking part 28 and a lead end part locking region 35 held to the end part locking part 26 almost in parallel to each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a battery pack in which a plurality of cylindrical unit cells are electrically connected by lead plates and a method for manufacturing the same.

  The battery pack can increase the output current by increasing the number of cells connected in parallel, and can increase the output voltage by increasing the number of cells connected in series. For this reason, battery packs used in applications requiring high output, such as bicycles, power tools, automobiles, etc., connect a plurality of unit cells in parallel and further connect them in series to increase the output. ing. As a battery pack containing a large number of unit cells, both ends of the unit cell are held by the end plate and placed at a fixed position, and a lead plate is placed at a fixed position of the end plate. A battery pack that is spot-welded to a partial electrode has been developed (see Patent Document 1).

JP 2008-91233 A

  When spot welding a lead plate to a unit cell, from the standpoint of improving work efficiency, place the lead plate on both sides of the stacked battery block while keeping the unit cells horizontally, and place the lead plate vertically. It is held by a jig etc. while maintaining the posture, and is welded by a spot welder from both sides. At this time, until the battery pack is fixed to the jig, it is necessary to keep the lead plate standing vertically without falling from the end plate. Since a thin metal plate is used for the lead plate, there is a possibility that the lead plate will fall down due to its own weight. For this reason, as shown in FIG. 15, the battery holder is provided with a plurality of temporary fixing portions 9 for temporarily fixing the lead plate 5 in a predetermined posture, and the fall due to the weight of the lead plate 5 is supported by the temporary fixing portion 9. I was blocking. In this example, the temporary fixing portion 9 includes a temporary fixing portion 9A provided horizontally at two locations at the lower end and a temporary fixing portion 9B provided vertically at one location at the upper end.

  However, with recent demands for higher output and higher capacity of battery packs, the number of unit cells used tends to increase. As a result, the number of unit cells constituting the battery block increases, and it is necessary to stack a large number of unit cells. Accordingly, the height of the lead plate fixed to the side surface of the battery block also increases. The higher the lead plate, the easier it is for the lead plate to fall down, so it may not be possible to hold the raised lead plate stably until the battery block is set in the jig using only the temporary fixing part as in the past. was there. Further, if the number of temporarily fixed portions is increased, the lead plate may be prevented from being fixed, or the number of contact points between the lead plate and the temporarily fixed portion may increase, resulting in rattling and noise.

  The present invention has been made in view of such a conventional background. A main object of the present invention is to provide a battery pack capable of reliably maintaining a lead plate in a vertical posture when spot welding the lead plate to a unit cell and a method for manufacturing the same.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, according to the first battery pack of the present invention, the outer shape is cylindrical, and the plurality of unit cells 10 provided with the end surface electrodes 11 on both end surfaces are connected to each other. A battery holder 20 for holding in a state of being stacked in a posture that is parallel and whose end faces are located on substantially the same plane, and the battery holder 20 is fixed to a fixed position of the battery holder 20 and held by the battery holder 20 A pair of flexible metal lead plates 30 which are welded to the end surface electrodes 11 on both sides of the battery block 1 which is a laminate of the unit cells 10 and electrically connect adjacent unit cells 10; The battery holder 20 includes an end locking portion 26 that is open to hold one end of the lead plate 30, and a stacking direction of the plurality of unit cells 10 among the lead plates 30. In the middle An intermediate locking portion 28 that is open to hold the portion is formed, and the lead plate 30 is connected to the lead intermediate locking region 34 that is held by the intermediate locking portion 28 and the end locking portion 26. The held lead end locking regions 35 can be formed substantially parallel to each other. As a result, the battery holder can hold a part of the lead plate with the end locking portion and the intermediate locking portion, and stably hold the lead plate even if the number of unit cells is increased and the lead plate becomes larger. The work which welds a unit cell to a lead board can be performed reliably. In addition, stability is also increased by holding the lead plate at two portions separated in parallel.

  Further, according to the second battery pack, the intermediate locking portion 28 can hold the lower end of the lead intermediate locking region 34 by inserting it into the opening portion. Accordingly, by holding the middle of the lead plate from the lower end in the horizontal direction, it is possible to prevent the lead plate from falling off and securely hold the lead plate.

  Further, according to the third battery pack, the end locking portion 26 has an end protrusion 27 protruding upward, and the intermediate locking portion 28 has an intermediate protrusion 29 protruding upward. The end latching portion 26 and the intermediate latching portion 28 hold the lead plate 30 by sandwiching the surface of the lead plate 30 with the end projection 27 and the intermediate projection 29, respectively. Can do. As a result, the end protrusion and the intermediate protrusion protrude so as to protrude from the surface of the lead plate, and the lead plate can be held so as not to fall down by its own weight.

  Furthermore, according to the fourth battery pack, the back surface of the end protrusion 27 is formed in an inclined surface so that the opening of the end locking portion 26 becomes narrower toward the bottom. The back surface of the intermediate protrusion 29 can be formed into an inclined surface so that the opening of the locking portion 28 becomes narrower toward the bottom. As a result, the lead plate inserted into the end projection and the intermediate projection can be smoothly guided toward the bottom of each opening on the inclined surface, and the lead plate can be securely held.

  Furthermore, according to the fifth battery pack, the stacked body of the unit cells 10 has a cylindrical end face disposed in an offset shape in the stacking direction, and the lead plate 30 is disposed in the offset shape. It can be formed in a zigzag shape so as to coincide with the end face of the unit cell 10. As a result, even if the lead plate is not linear and cannot be inserted in a sliding manner on the end face of the stacked body in which the unit cells are stacked in a staggered manner, the structure is such that the intermediate locking portion and the end locking portion are locked. The advantage that it can be held without falling is obtained.

  Furthermore, according to the sixth battery pack, the end locking portion 26 is formed so as to straddle between adjacent battery storage portions of the battery storage portion that stores the cylindrical unit cell 10. be able to. Thereby, an end latching | locking part can be arrange | positioned in the dead space produced between cylindrical unit cells, and a space can be used effectively.

  Furthermore, according to the seventh battery pack, the lead plate 30 has, at its lower end, the lead end portion locking region 35 between the adjacent unit cells 10 of the plurality of unit cells 10 to be connected. Can be formed. Thus, when the lead end locking region is disposed between the unit cells, when the lead plate set in the battery holder is welded to the unit cell, the end locking unit interferes with the welding operation. Can be avoided.

  Furthermore, according to the eighth battery pack, the lead end locking region 35 can be formed in a concave step shape formed substantially at the center of the lower end of the lead plate 30. Thereby, it is possible to hold the lead plate in a balanced manner by locking only the central portion, not the entire lower end of the lead plate.

  Furthermore, according to the ninth battery pack, the number of stacked unit cells 10 constituting the stacked unit of the unit cells 10 can be five or more. Accordingly, even a vertically long lead plate connecting five or more cells at the end face can be stably held and spot welded.

  Furthermore, according to the tenth battery pack, the battery holder 20 is provided with a guide portion 25 for guiding the lead plate 30 to a predetermined position. A gap is formed between the lead plate 30 and the guide portion 25 in a state where the lead plate 30 is inserted into the frame of the guide portion 25. can do. Thereby, in addition to holding the lead plate at a predetermined position of the battery holder, by providing a clearance between the lead plate and the guide portion, the flexible lead plate is deformed to form the end locking portion and It can be easily inserted into the intermediate locking portion.

  Furthermore, according to the eleventh battery pack manufacturing method, the plurality of unit cells 10 having the cylindrical outer shape and having the end surface electrodes 11 on both end surfaces, and the plurality of unit cells 10 are parallel to each other and are end surfaces. A battery holder 20 for holding in a stacked state in a posture positioned substantially on the same plane, and a stack of the unit cells 10 fixed to a fixed position of the battery holder 20 and held by the battery holder 20 A battery pack manufacturing method comprising a pair of flexible metal lead plates 30 welded to the end surface electrodes 11 on both sides of the body and electrically connected to the adjacent unit cells 10, respectively. When the unit cell 10 is set in the battery holder 20, and the lower end of the lead plate 30 is held by the end locking portions 26 formed in the battery holder 20 on both side end surfaces of the battery holder 20. Further, the lead plate 30 is translated so that a part of the lead plate 30 in the stacking direction of the plurality of unit cells 10 is held by the intermediate locking portion 28 formed in the battery holder 20. And a step of welding the lead plate 30 to the end face electrode 11 of the unit cell 10. Accordingly, the lead plate can be slidably set and held at the end locking portion and the intermediate locking portion of the battery holder, respectively, and is particularly suitable for the operation of locking the relatively short lead plate to the battery holder.

  Furthermore, according to the twelfth battery pack manufacturing method, the outer shape is cylindrical, and the plurality of unit cells 10 provided with the end surface electrodes 11 on both end surfaces are parallel to each other and the end cells are end surfaces. A battery holder 20 for holding in a stacked state in a posture positioned substantially on the same plane, and a stack of the unit cells 10 fixed to a fixed position of the battery holder 20 and held by the battery holder 20 A battery pack manufacturing method comprising: a pair of flexible metal lead plates 30 welded to end face electrodes 11 on both sides of a body and electrically connected to adjacent unit cells 10; , The step of setting the unit cell 10 in the battery holder 20, and the lower end of the lead plate 30 on the both side end surfaces of the battery holder 20 are locked to the end locking portions 26 formed on the battery holder 20. Further, by rotating the lead plate 30 with this position as a fulcrum, an intermediate locking portion formed in the battery holder 20 is formed in the middle of the lead plate 30 in the stacking direction of the plurality of unit cells 10. 28, and a step of welding the lead plate 30 to the end face electrode 11 of the unit cell 10. This allows the lead plate to be inserted into the end latching portion of the battery holder and then inserted into the intermediate latching portion by rotating the lead plate, so it can be set in the battery holder regardless of the length of the lead plate It becomes.

It is an external appearance perspective view of a battery pack. It is the external appearance perspective view which looked at the battery pack of FIG. 1 from the back surface. It is a disassembled perspective view of the battery pack of FIG. It is a disassembled perspective view of the battery pack of FIG. It is a disassembled perspective view of the battery block of FIG. FIG. 6 is a perspective view of the lead plate of FIG. 5. It is a side view of the battery holder of FIG. FIG. 5 is a cross-sectional view taken along line VIII-VIII in FIG. 4 and an enlarged perspective view showing an end locking portion. It is sectional drawing of the edge part latching | locking part of FIG. FIG. 5 is a cross-sectional view taken along line XX in FIG. 4 and an enlarged perspective view showing an end locking portion. It is sectional drawing of the edge part latching | locking part of FIG. It is an expansion perspective view which shows a mode that the battery block of FIG. 4 hold | maintains a lead plate. It is an expansion perspective view which shows an example which inserts a lead board in the battery block of FIG. It is an expansion perspective view which shows the other example which inserts a lead board in the battery block of FIG. It is a side view which shows the conventional battery block.

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

  FIGS. 1-14 shows the example applied to the battery pack for assist bicycles as the battery pack 100 which concerns on one embodiment of this invention. 1 is an external perspective view of the battery pack 100, FIG. 2 is an external perspective view of FIG. 1 viewed from the back, FIG. 3 is an exploded perspective view of FIG. 1, and FIG. 4 is an exploded perspective view of FIG. 5 is an exploded perspective view of the battery pack 100 of FIG. 4, FIG. 6 is a perspective view of the lead plate 30 of FIG. 5, FIG. 7 is a side view of the battery holder 20 of FIG. FIG. 9 is a cross-sectional view of the end locking portion 26 of FIG. 8, and FIG. 10 is a cross-sectional view and end locking portion taken along line XX of FIG. 11 is a cross-sectional view of the end locking portion 26 of FIG. 10, FIG. 12 is an enlarged perspective view of the battery holder 20 of FIG. 4 holding the lead plate 30, and FIG. FIG. 14 is an enlarged perspective view showing an example of inserting the lead plate 30 into the battery holder 20 of FIG. An enlarged perspective view showing another example of inserting the plate 30, respectively. The battery pack 100 shown in these drawings includes an outer case 40 and a battery block 1 housed inside. As shown in FIGS. 1 to 4, the outer case 40 is divided into an upper case 41 and a lower case 42. The outer case 40 is made of a plastic having excellent insulating properties. A handle 43 that is convenient to carry is provided at one end, and a connector 3 is provided at the other end for connection to an assist bicycle that is a driving device. The upper case 41 and the lower case 42 are formed with locking projections and locking holes at two locations on each side, and the protrusions provided in one case are locking holes provided in the other case. To be connected to each other. Further, the outer case 40 is fixed by screwing four places with screws.

  The upper case 41 and the lower case 42 are each formed in a bottomed box shape so that the battery block 1 can be stored inside the outer case 40, and form a storage space for storing the battery block 1. As shown in FIGS. 3 and 4, the battery block 1 is disposed and accommodated between the upper case 41 and the lower case 42 with the cover 2 covering the outside. The cover 2 is formed in a bag shape with waterproof and insulating polyethylene or the like, and sealed with the battery block 1 inserted therein.

The battery block 1 is electrically connected to the connector 3 via a lead wire. The connector 3 is fixed to the outer case 40 by closing the upper surface with the upper case 41 so as to be fitted into a frame opened in a U shape on the bottom surface of the lower case 42. The connector 3 has a plurality of connection sockets for connecting to the connection terminals of the assist bicycle.
(Battery block 1)

As shown in the exploded perspective view of FIG. 5, the battery block 1 includes a plurality of unit cells 10, a battery holder 20 in which the unit cells 10 are arranged at fixed positions, and an outside of the battery holder 20. A lead plate 30 welded to the circuit board, a circuit board 46 to which the lead board 30 is connected, and a substrate holder 44 for housing the circuit board 46.
(Unit cell 10)

  The unit cell 10 is a rechargeable secondary battery, and a lithium ion secondary battery can be suitably used. However, a nickel hydrogen battery or a nickel cadmium battery may be used as the unit cell 10. The unit cell 10 is a cylindrical battery, and is held by the battery holder 20 in a posture in which a plurality of unit cells are arranged in parallel and a plurality of unit cells 10 are stacked thereon. Here, in the unit cell 10, adjacent unit cells 10 stacked in the vertical direction are arranged in an offset shape or a zigzag shape with the center axis shifted. Thereby, the dead space which arises by lamination | stacking of a cylindrical battery can be reduced. In the example of FIG. 5, seven unit cells 10 arranged side by side are stacked in five stages, and a total of 35 unit cells 10 are used. Further, five unit cells 10 arranged in multiple directions are connected in parallel, and these are connected in series in seven rows. Of course, it goes without saying that the number of stacked layers and the number of unit cells can be changed according to the required capacity and voltage of the battery block 1.

Furthermore, the unit cells 10 have their end faces arranged on substantially the same plane. Thus, by arranging the unit cells 10 so as not to be arranged in the length direction, the connection between the unit cells 10 can be processed by welding with the lead plate 30. In particular, the unit cells 10 can be connected to each other by welding the lead plates 30 on both sides of the unit cells 10, that is, on both sides of the exterior case 40 as described later. Further, the configuration in which the unit cells 10 are stacked as only one unit in the length direction has an advantage that heat is easily radiated through the outer case 40 because both end surfaces of the unit cells 10 face the outer case 40.
(Battery holder 20)

  The battery holder 20 is divided into left and right parts and is constituted by a first holder 21 and a second holder 22, and holds the unit cell 10 so as to be sandwiched from both sides. The first holder 21 and the second holder 22 are formed substantially mirror-symmetrically. Each of the first holder 21 and the second holder 22 forms a plurality of cylindrical holding cylinders 23 into which the unit cells 10 are inserted. The first holder 21 and the second holder 22 having the holding cylinder 23 are integrally molded. The battery holder 20 is made of a resin such as plastic having excellent insulating properties.

  The holding cylinder 23 is provided through an electrode window 24 for welding the lead plate 30 to the end face electrode 11 of the unit cell 10. Each electrode window 24 is formed in a size capable of welding the lead plate 30. The battery holder 20 inserts the unit cell 10 through the holding cylinder 23 and holds the plurality of unit cells 10 at predetermined positions. The battery holder 20 shown in the figure is provided with 35 electrode windows 24 because it connects and holds 35 cylindrical unit cells 10. Thirty-five electrode windows 24 are provided in each stage and arranged in five stages. Further, in the holding cylinder 23 shown in FIG. 5, other unit cells 10 are arranged in the valleys of the unit cells 10 arranged adjacent to each other, and the unit cells 10 arranged in a plurality of stages are stacked. It is arranged. Further, the holding cylinder 23 shown in the drawing is divided into two in the middle in the axial direction, and is connected to each battery holder 20. Each battery holder 20 is integrally formed of plastic in a shape formed by connecting the ends of the divided holding cylinders 23. The holding cylinder 23 inserts the unit cell 10 from an opening that is a divided end, and connects the pair of holding cylinders 23 to each other to hold the plurality of unit cells 10 at a fixed position of the battery holder 20.

The holding cylinder 23 divided in the middle has an inner surface formed in a tapered shape in which the inner diameter gradually decreases from the divided end side toward the holder side plate side. The holding cylinder 23 can hold the unit cell 10 in a fixed position by bringing the portion protruding from the inner surface of the end of the battery holder 20 into surface contact with the surface of the unit cell 10. As described above, the structure in which the holding cylinder 23 is divided has a feature that simplifies the design of a mold for molding plastic and facilitates plastic molding.
(Guide part 25)

  The battery holder 20 is connected to one end of a holding cylinder 23 that houses the unit cell 10, and a lead plate 30 is placed in a guide portion 25 provided on the outer surface of the battery holder 20 and arranged at a fixed position. The battery holder 20 is connected by welding a lead plate 30 to the end face electrode 11 exposed from the electrode window 24. The battery holder 20 shown in FIGS. 3 to 4 and FIG. 5 is provided with a guide portion 25 on which the lead plate 30 is disposed on the outer surface, and the lead plate 30 is placed in the guide portion 25 at a fixed position.

  Furthermore, as shown in FIGS. 12 and 7, the battery holder 20 can also be brought into contact with and locked by the lead plate 30 on the back side of the guide portion 25. That is, the unit 10 can also be used to hold the lead plate 30 by using the guide portion 25 provided so that the unit cell 10 does not fall out of the holding cylinder 23. As a result, the lead plate 30 can be held and held on the battery holder 20 in a wider area.

In each unit cell 10, lead plates 30 are welded to the end face electrodes 11 at both ends, and are connected in series and in parallel. Each lead plate 30 is connected to the circuit board 46. The circuit board 46 is accommodated in the board holder 44 disposed on the upper surface of the battery holder 20 in FIGS. 3, 4, and 5. The substrate holder 44 is configured in a frame shape having an opening large enough to accommodate the circuit board 46.
(Circuit board 46)

The circuit board 46 is mounted with an electronic circuit such as a control circuit that controls discharge or charge / discharge of the unit cell 10. The circuit board 46 has a flat plate shape and extends along the length direction of the battery holder 20 as shown in FIGS. The battery holder 20 has a substrate holder 44 for housing the circuit substrate 46 placed on the upper surface thereof. The circuit board 46 is fixed to the upper surface of the battery holder 20 and necessary wiring is performed, and then stored in the outer case 40. Furthermore, the connection part 33 of each lead board 30 protrudes from the upper surface of the battery holder 20, and is connected with the circuit board 46 by a lead wire. With this configuration, the wiring between the lead plate 30 and the circuit board 46 can be made the shortest distance, the assembly process can be simplified, and lead wires of other members can be minimized.
(Lead plate 30)

  As shown in the perspective views of FIGS. 5 and 6, the lead plate 30 is zigzag or corrugated as a whole so that the vertical unit cells 10 are connected in two rows in a state where the unit cells 10 are stacked in an offset shape. Is formed. The lead plate 30 is formed of a metal plate having excellent conductivity and flexibility. The lead plate 30 is provided with a reactive current reducing slit 16 at a position where spot welding is performed on the end surface electrode 11 of the unit cell 10. Further, a connecting portion 33 connected to the circuit board 46 is provided at the upper end of the lead plate 30 so as to protrude. The connecting portion 33 is connected to the circuit board 46 via the lead wire 13. Furthermore, the lead plate 30 has a lead intermediate locking region 34 held in an intermediate locking portion 28 of the battery holder 20 described later and a lead end locking region 35 held in the end locking portion 26 parallel to each other. Is formed.

  As shown in FIGS. 5 and 6, the lead plate 30 does not have a shape that completely covers the end surface electrode 11 of the stacked body of the unit cells 10, and is formed slightly smaller than this. As a result, a gap is formed between the lead plate 30 and the guide portion 25 in a state where the lead plate 30 is inserted into the frame of the guide portion 25 of the lead plate 30. This gap becomes play, so that the lead plate 30 can be disposed on the guide portion 25, and the lead plate 30 can be deformed and easily inserted into the end locking portion 26 and the intermediate locking portion 28.

In the example of FIG. 5, three first lead plates 31 that connect the five-stage unit cells 10 in two rows and one second lead plate 32 that connects the five-stage unit cells 10 in one row are used. Has been. Here, three first lead plates 31 are arranged, and one second lead plate 32 is arranged on the left side.
(End locking part 26)

Furthermore, as shown in FIGS. 7 to 14, the battery holder 20 forms an end locking portion 26 and an intermediate locking portion 28 that are opened to hold the lead plate 30 in place. As shown in FIGS. 7 and 8, the end locking portion 26 holds a lead end locking region 35 at the substantially center of the lower end of the lead plate 30. Therefore, the end locking portion 26 is formed between the holding cylinders 23 so as to straddle the electrode window 24. In the example of FIG. 7, it is formed in a straight line passing through the tangential portion of the adjacent electrode window 24. In this way, by providing the end locking portion 26 between the unit cells 10, the unit cell 10 can be positioned away from the welded portion between the end surface electrode 11 and the lead plate 30 and set in the battery holder 20. When the lead plate 30 is welded to the unit cell 10, it is possible to avoid a situation in which the end locking portion 26 interferes with the welding operation. Moreover, the advantage which can use effectively the dead space produced when laminating | stacking cylindrical unit cells 10 is also acquired.
(End projection 27)

Further, the end locking part 26 is provided with end protrusions 27 protruding in the direction of closing the electrode window 24 at both ends of the straight line. As a result, the end protrusion 27 can be protruded so as to protrude from the surface of the lead plate 30, and the lead plate 30 can be held so as not to fall down due to its own weight. Further, as shown in the cross-sectional view of FIG. 9, the end projection 27 has a back surface as an inclined surface. By forming in this way, the lead end locking region 35 at the lower end of the lead plate 30 inserted inside the end protrusion 27 is guided by the inclined surface in the downward direction, that is, in the direction in contact with the electrode window 24. For this reason, the opening of the end locking portion 26 is formed so as to narrow toward the bottom by the inclined surface.
(Intermediate locking portion 28)

  The intermediate locking portion 28 holds a lead intermediate locking region 34 formed in the middle in the length direction of the lead plate 30. As shown in FIG. 10, the intermediate locking portion 28 is linearly arranged so as to cover the lower end of the second holding cylinder 23 from the top. Further, an intermediate protrusion 29 protruding in the direction of closing the electrode window 24 is formed at the corner on the edge side. As a result, the intermediate protrusion 29 can be projected so as to protrude from the surface of the lead plate 30, and the lead plate 30 can be held so as not to fall down due to its own weight. Further, as shown in the sectional view of FIG. 11, the intermediate projection 29 has a back surface as an inclined surface. By forming in this way, the lead intermediate locking region 34 of the lead plate 30 inserted inside the intermediate protrusion 29 is guided in the downward direction, that is, the direction in contact with the electrode window 24 by the inclined surface. For this reason, the opening of the intermediate | middle latching | locking part 28 is formed so that it may become narrow toward a bottom direction with an inclined surface.

  The end locking part 26 and the intermediate locking part 28 are formed in parallel to each other. Correspondingly, the lead plate 30 also includes a lead intermediate locking region 34 held by the intermediate locking portion 28 of the battery holder 20 and a lead end locking region 35 held by the end locking portion 26. They are formed parallel to each other. As a result, the lead end portion locking region 35 is inserted into the end portion locking portion 26, and the lead intermediate locking region 34 is locked to the intermediate locking portion 28 on the upper side to be separated from the lower end and the middle. By holding in parallel at two places, the lead plate 30 can be easily held in a vertical posture so as not to fall down. Further, even if the number of stacked unit cells 10 is increased and the lead plate 30 becomes larger, it can be stably held, and the operation of welding the unit cell 10 to the lead plate 30 can be performed reliably. In other words, as shown in FIG. 15, in the temporary fixing portion 9B that is held in the vertical direction on the side surface of the lead plate, there is a problem that when the lead plate 30 becomes high, it tends to come off due to its own weight. By adopting a configuration in which the lead plate 30 is held from the lower end, there is an advantage that the lead plate 30 can be reliably held by preventing such dropout. In this example, the number of stacked unit cells 10 constituting the battery block 1 is five or more, and the conventional method cannot hold the lead plate 30 and falls due to its own weight. Even the plate 30 can be stably held and spot-welded.

  Further, conventionally, the lead plate is provided with a hole, and the battery holder is provided with a protrusion that is inserted through the hole to hold and position the lead plate. Positioning is also performed simultaneously with holding of the lead plate with the stop portion 28, so that there is also an advantage that such a configuration is unnecessary and the manufacturing cost of a mold or the like can be reduced. In addition, by eliminating the opening of the lead plate, the current path flowing through the lead plate can be increased, which is advantageous in terms of temperature characteristics.

  The lead end portion locking region 35 shown in FIG. 6 is a concave step formed in the approximate center of the lower end of the lead plate 30. As a result, the lead plate 30 can be held in a well-balanced manner by locking not only the entire lower end of the lead plate 30 but only the central portion in one place.

Moreover, the laminated body of the unit cells 10 has the unit cells 10 stacked in an offset shape as described above. Therefore, the lead plate 30 is formed in a zigzag shape so as to coincide with the end face of the unit cell 10 arranged in an offset shape. In other words, the lead plate cannot be formed linearly, and it is not easy to form, for example, a U-shaped guide rail that guides both sides of the lead plate along the insertion direction. Therefore, in the present embodiment, as described above, the intermediate holding portion that holds the intermediate portion is formed in a horizontal posture so as not to be in a posture along the slide direction, but to intersect with the slide direction. As a result, even if the lead plate is not linear and cannot be slidably inserted as it is at the end face of the stacked body in which the unit cells 10 are stacked in a staggered manner, it is locked to the intermediate locking portion 28 and the end locking portion 26. It will be possible to hold it so that it will not fall down depending on the structure.
(Lead plate slide-in type setting method)

  The procedure for setting the lead plate 30 to the battery holder 20 will be described with reference to FIG. First, with the unit cell 10 set in the battery holder 20, the lead plate 30 is inserted from the upper side to the lower side on the side surface of the battery holder 20. At this time, the lead end locking region 35 of the lead plate 30 is inserted into the opening of the end locking portion 26 of the battery holder 20, and the lead intermediate locking region 34 is inserted into the opening of the intermediate locking portion 28. . Here, the lead plate 30 is locked by being translated from top to bottom. In this state, the lead plate 30 is securely held by the end holding portion and the intermediate holding portion as shown in FIG. 12, so the battery block 1 is transferred to a jig and the lead plate 30 is moved to the end face electrode by a spot welder. 11 and spot welding. This setting method is particularly suitable for setting the relatively short lead plate 30 to the battery holder 20.

  The method for setting the lead plate is not limited to such a slide-in type. For example, after the lead end locking area 35 is first inserted into the opening of the end locking section 26, the lead plate is elastically deformed so as to press against the battery holder, so that the lead intermediate locking area 34 is moved to the intermediate locking section 28. It can also be inserted into the opening. In this case, since the lead plate is deformed so as to be bent, it is effective when the load on the lead plate is large and the lead plate is relatively small.

  A method of rotating the lead plate as shown in FIG. 14 can also be used. In this method, with the unit cell 10 set in the battery holder 20, only the lead end locking region 35 of the lead plate 30 is locked to the end locking portion 26, and the lead plate 30 is rotated using this as a fulcrum. In this manner, the lead intermediate locking region 34 is inserted into the intermediate locking portion 28. That is, the lead plate 30 is elastically deformed by twisting it a little, and the lead intermediate locking region 34 is inserted into the intermediate locking portion 28. This method is less burdensome because the deformation of the lead plate is in the twist direction, and can be applied even if the lead plate is long.

  The battery pack and the manufacturing method thereof according to the present invention can be suitably used as a power supply device for an assist bicycle.

DESCRIPTION OF SYMBOLS 100 ... Battery pack 1 ... Battery block 2 ... Cover 3 ... Connector 9, 9A, 9B ... Temporary fixing part 10 ... Unit cell 11 ... End surface electrode 20 ... Battery holder 21 ... First holder 22 ... Second holder 23 ... Holding cylinder 24 ... electrode window 25 ... guide part 26 ... end locking part 27 ... end protrusion 28 ... intermediate locking part 29 ... intermediate protrusion 30 ... lead plate 31 ... first lead plate 32 ... second lead plate 33 ... connection part 34 ... Lead intermediate locking region 35 ... Lead end locking region 40 ... Exterior case 41 ... Upper case 42 ... Lower case 43 ... Handle 44 ... Substrate holder 46 ... Circuit board

Claims (12)

A plurality of unit cells (10) provided with end face electrodes (11) on both end faces as a cylindrical shape,
A battery holder (20) for holding the plurality of unit cells (10) in a state of being stacked in parallel with each other and in a posture in which end faces are positioned on substantially the same plane;
End electrodes (11) on both sides of the battery block (1), which is a laminate of the unit cells (10) fixed in place at the battery holder (20) and held by the battery holder (20), respectively. A pair of flexible metal lead plates (30) welded to and electrically connected adjacent unit cells (10), and
A battery pack comprising:
The battery holder (20)
An end locking portion (26) opened to hold one end of the lead plate (30);
Of the lead plate (30), forming an intermediate locking portion (28) opened to hold a part of the middle in the stacking direction of the plurality of unit cells (10),
The lead plate (30) is a lead intermediate locking region (34) held by the intermediate locking portion (28), and a lead end locking region (35) held by the end locking portion (26). Are formed substantially parallel to each other. The battery pack according to claim 1,
The battery pack, wherein the intermediate locking portion (28) is formed by inserting and holding the lower end of the lead intermediate locking region (34) into the opening portion. The battery pack according to claim 2,
The end locking part (26) has an end protrusion (27) protruding upward,
The intermediate locking portion (28) has an intermediate protrusion (29) protruding upward,
The end locking portion (26) and the intermediate locking portion (28) are formed by sandwiching the surface of the lead plate (30) with the end protrusion (27) and the intermediate protrusion (29), respectively. (30) The battery pack characterized by the above-mentioned. The battery pack according to claim 3,
The back surface of the end protrusion (27) is formed into an inclined surface so that the opening of the end locking portion (26) becomes narrower toward the bottom,
A battery pack, wherein the back surface of the intermediate projection (29) is formed in an inclined surface so that the opening of the intermediate locking portion (28) becomes narrower toward the bottom. The battery pack according to any one of claims 1 to 4,
The unit cell (10) stack has a cylindrical end face arranged in an offset shape in the stacking direction,
The battery pack, wherein the lead plate (30) is formed in a zigzag shape so as to coincide with an end face of the unit cell (10) arranged in the offset shape. The battery pack according to claim 5,
The battery, wherein the end locking portion (26) is formed so as to straddle between adjacent battery storage portions of the battery storage portion for storing the cylindrical unit cell (10). pack. The battery pack according to claim 6,
The lead plate (30) is formed at its lower end with the lead end locking region (35) between adjacent unit cells (10) of a plurality of unit cells (10) to be connected. A battery pack characterized by that. The battery pack according to claim 7,
The battery pack according to claim 1, wherein the lead end portion locking region (35) is a concave step formed substantially at the center of the lower end of the lead plate (30). The battery pack according to any one of claims 1 to 8,
A battery pack, wherein the number of stacked unit cells (10) constituting the stacked unit of unit cells (10) is five or more. The battery pack according to any one of claims 1 to 9,
The battery holder (20) is provided with a guide portion (25) for guiding the lead plate (30) to a predetermined position,
The guide portion (25) is formed in a frame shape so as to surround the outer shape of the lead plate (30), and
A gap is formed between the lead plate (30) and the guide portion (25) in a state where the lead plate (30) is inserted into the frame of the guide portion (25). Battery pack. A plurality of unit cells (10) provided with end face electrodes (11) on both end faces as a cylindrical shape,
A battery holder (20) for holding the plurality of unit cells (10) in a state of being stacked in parallel with each other and in a posture in which end faces are positioned on substantially the same plane;
The battery holder (20) is fixed at a fixed position and is welded to the end surface electrode (11) on both sides of the stacked body of the unit cells (10) held by the battery holder (20) and adjacent to each other. A pair of flexible metal lead plates (30) formed by electrically connecting the unit cells (10);
A method for producing a battery pack comprising:
Setting the unit cell (10) in the battery holder (20);
On both side end surfaces of the battery holder (20), the lower end of the lead plate (30) is held by an end locking portion (26) formed on the battery holder (20), and the lead plate (30) The lead plate (30) in parallel so that an intermediate part in the stacking direction of the plurality of unit cells (10) is held by an intermediate locking portion (28) formed in the battery holder (20). A process of moving;
Welding the lead plate (30) to the end face electrode (11) of the unit cell (10);
The manufacturing method of the battery pack characterized by including. A plurality of unit cells (10) provided with end face electrodes (11) on both end faces as a cylindrical shape,
A battery holder (20) for holding the plurality of unit cells (10) in a state of being stacked in parallel with each other and in a posture in which end faces are positioned on substantially the same plane;
The battery holder (20) is fixed at a fixed position and is welded to the end surface electrode (11) on both sides of the stacked body of the unit cells (10) held by the battery holder (20) and adjacent to each other. A pair of flexible metal lead plates (30) formed by electrically connecting the unit cells (10);
A method for producing a battery pack comprising:
Setting the unit cell (10) in the battery holder (20);
On both side end surfaces of the battery holder (20), the lower end of the lead plate (30) is locked to an end locking portion (26) formed on the battery holder (20), and the position is used as a fulcrum. An intermediate latch formed on the battery holder (20) by rotating the lead plate (30) and, in the lead plate (30), a part of the middle in the stacking direction of the plurality of unit cells (10) Locking to the part (28);
Welding the lead plate (30) to the end face electrode (11) of the unit cell (10);
The manufacturing method of the battery pack characterized by including.

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