JP5372562B2 - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save a power loss in a large current by making small an electric resistance with a thick metal plate, while surely welding and connecting a lead plate with electrodes of batteries and connecting the lead plate and the metal plate simply, easily and still in space-saving. <P>SOLUTION: The battery pack 100 includes a connecting material 10 for outputting which connects a lead plate 11 with an electrode of batteries and connects the lead plate 11 with a metal plate 20. The lead plate 11 is formed in a shape having a cylindrical peripheral wall 13 around a welding face 12 where a metal sheet thinner than the metal plate 20 is welded with the electrodes of the batteries, and the metal plate 20 includes through-holes 21 through which the cylindrical peripheral wall 13 of the lead plate 11 is inserted and engaged, and the lead plate 11 is connected with the metal plate 20 by inserting the lead plate 11 into the through-hole 21 of the metal plate 20 while the cylindrical peripheral wall 13 of the lead plate 11 is made to contact an inner face of the through-hole 21 of the metal plate 20. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a battery pack that is charged and discharged with a large current.

  A large output battery pack has a large output voltage by connecting a large number of batteries in series, and a large output current by connecting them in parallel. In this battery pack, the electric resistance is reduced by using a thick metal plate on the output side of the battery from which power is extracted. This is because the power loss of the metal plate increases in proportion to the product of the electric resistance and the square of the current. A metal plate made of a thick metal plate cannot be directly welded and connected to the battery electrode, so a thin metal plate lead plate is connected to the battery electrode by spot welding or the like. It is connected to the metal plate with screws. In this connection structure, in addition to the time and effort required to connect the metal plate and the lead plate, there is a drawback in that the size is increased because a portion for connecting the lead plate to the metal plate is required. On the other hand, a structure in which a relatively thick metal plate can be directly welded to a battery electrode has been developed (see Patent Document 1).

JP 2008-66090 A

  The metal plate described in Patent Document 1 is composed of two laminated metal plates. The metal plate uses copper and nickel which form a binary alloy by welding. This metal plate is resistance-welded to the battery electrode to alloy copper and nickel. This metal plate can be connected by resistance welding to the electrode of the battery, but there is a problem that it is restricted by the thickness that can be welded to the electrode of the battery. As the metal plate becomes thicker, the welding current needs to be increased. However, if the welding current is too large, damage to the metal case of the battery increases, and the metal plate cannot be stably welded without damaging the metal case of the battery. There is also a problem that a thick metal plate having a large heat capacity is overheated to overheat the welded battery and adversely affect the heat. Furthermore, the metal plate subjected to the thickness restriction has a drawback that the electric resistance cannot be reduced, and the loss increases with a large current.

  The present invention has been developed for the purpose of solving the above drawbacks. An important object of the present invention is to connect the lead plate and the metal plate easily and easily in a space-saving manner while securely welding and connecting the lead plate to the battery electrode. An object of the present invention is to provide a battery pack that can reduce resistance and reduce power loss at a large current.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a battery pack according to the first aspect of the present invention is a battery pack having a plurality of battery cells and an output connecting member electrically connected to the electrodes of the battery cells. The output connecting member includes a lead plate welded to the electrode of the battery cell, and a metal plate connected to the lead plate, and the lead plate is a metal thinner than the metal plate. The metal plate is formed into a shape including a welding surface formed by a plate and welded to the electrode of the battery cell, and a cylindrical peripheral wall formed around the welding surface, and the metal plate is a tube of the lead plate A through-hole is provided in which a cylindrical peripheral wall can be inserted and fitted, and the lead plate is inserted into the through-hole of the metal plate with the cylindrical peripheral wall of the lead plate contacting the inner surface of the through-hole of the metal plate. The Lee Plate is connected to the metal plate. In this battery pack, the lead plate and the metal plate are simply and easily connected in a space-saving manner while the lead plate is securely welded and connected to the battery electrode, and the electric resistance is reduced with the thick metal plate. As a result, the power loss at a large current can be reduced. This is because a lead plate made of a metal plate thinner than the metal plate is connected by welding to the electrode of the battery, and this lead plate is inserted into the through hole of the metal plate and connected to the thick metal plate.

  Moreover, according to the battery pack which concerns on a 2nd side surface, the cylindrical surrounding wall of a lead plate is press-fit in the through-hole of the said metal plate, and it can connect to a metal plate. Thereby, the cylindrical peripheral wall of the lead plate is press-fitted into the through hole and electrically connected, so that the lead plate can be electrically connected to the metal plate more easily and reliably.

  Furthermore, according to the battery pack which concerns on a 3rd side surface, the said lead plate can make a welding surface into a disk shape, and can make a cylindrical surrounding wall cylindrical. This battery pack can be electrically connected by inserting the lead plate into the through hole of the metal plate without directivity.

  Furthermore, according to the battery pack which concerns on a 4th side surface, the said lead board can also provide the collar which protrudes outside in the opening edge of a cylindrical surrounding wall. This battery pack can be connected by inserting the cylindrical peripheral wall of the lead plate into a fixed position of the metal plate. This is because the lead plate can be connected to the metal plate by inserting the brim to a position where it comes into contact with the surface of the metal plate.

  Furthermore, according to the battery pack of the fifth aspect, the flange of the lead plate can be fixed to the metal plate by welding, soldering, or brazing. As a result, the lead plate and the metal plate can be reliably electrically connected.

  Furthermore, according to the battery pack of the sixth aspect, the lead plate can be a metal plate made of nickel or a nickel alloy. As a result, the lead plate can be reliably welded to the electrode of the battery.

  Furthermore, according to the battery pack which concerns on a 7th side surface, the said metal plate can be made into the metal plate which consists of copper or a copper alloy. Thereby, while being able to make the electrical resistance of a metal plate small, the temperature difference of the battery connected by the metal plate of the outstanding heat conduction can be reduced.

  Furthermore, according to the battery pack of the eighth aspect, the lead plate is a metal plate thicker than 0.2 mm and thinner than 0.8 mm, and the metal plate is thicker than 1 mm and larger than 5 mm. Can be a thin metal plate. Thereby, the electrical resistance of the metal plate can be reduced and heat conduction can be improved while the lead plate is reliably welded to the electrode of the battery.

1 is an external perspective view of a battery pack according to Embodiment 1 of the present invention. It is a disassembled perspective view of the battery pack of FIG. It is sectional drawing of the battery pack of FIG. It is sectional drawing of the battery pack using the modification of an exterior case. It is a perspective view of a lead plate. FIG. 6 is a plan view of the lead plate of FIG. 5. FIG. 6 is a front view of the lead plate of FIG. 5. It is a front view which shows the state which mounted | wore the metal plate with the lead plate. It is a partially expanded sectional view in the VIII-VIII line of FIG.

Hereinafter, embodiments of the present invention will be described 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. Moreover, the member shown by the claim is not what specifies the member of embodiment. 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.
(Embodiment 1)

  A battery pack according to Embodiment 1 of the present invention is shown in FIGS. In these drawings, FIG. 1 is an external perspective view of a battery pack, FIG. 2 is an exploded perspective view, FIG. 3 is a sectional view, FIG. 4 is a sectional view of a battery pack according to a modification, and FIG. 6A and 6B are a plan view and a front view of the lead plate, FIG. 7 is a front view showing a state where the lead plate is mounted on the metal plate, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. The battery pack 100 shown in these drawings can be used as a power source for driving a motor for an electric motorcycle incorporating a plurality of battery cells.

As shown in the exploded perspective view of FIG. 2, the battery pack 100 includes a battery block 4 in which a plurality of battery modules 2 formed by linearly connecting battery cells 1 formed of a plurality of cylindrical batteries are connected in a plurality of stages. A connection material for connecting the battery cells 1 in series and in parallel, a circuit board 40 for mounting a voltage detection circuit for detecting the voltage of each battery cell 1 through the connection material, a battery block 4 and the circuit board 40 And an outer case 50 for storing the. The respective battery modules 2 are arranged in a plurality of rows in parallel postures with the same number of battery cells 1 connected in a straight line, and constitute a battery block 4. Further, the connection material includes an output connection material 10 and an intermediate connection material 30. Further, the output connection member 10 includes a lead plate 11 welded to the electrode of the battery cell and a metal plate 20 connected to the lead plate 11.
(Intermediate connecting material 30)

  The battery module 2 in FIG. 2 has five battery cells 1 connected in a straight line in series. The battery cell 1 is a lithium ion battery that is a cylindrical battery. The battery module 2 is manufactured by disposing an intermediate connection member 30 at a connection point between a plurality of battery cells 1 and welding the intermediate connection member 30 to the positive and negative electrodes of the adjacent battery cell 1. Since the battery cell 1 is a cylindrical battery, the battery module 2 is a cylindrical battery whose length is an integral multiple of the battery cell 1. There may be fewer than five battery modules 2 or more than five battery cells 1 connected in a straight line. The battery module 2 adjusts the voltage by the number of battery cells 1 connected in a straight line. Therefore, in the battery pack in which the battery module 2 is composed of the five battery cells 1, the five battery cells 1 are connected in series. Therefore, when a lithium ion battery having a rated voltage of 3.6 V is used for the battery cell 1 and five battery cells 1 are connected in a straight line to the battery module 2, the output voltage is 3.6 V × 5. = 18V. Further, by stacking the battery blocks 4 in two stages, the output voltage becomes 18V × 2 = 36V. The battery pack 100 in which the battery cell 1 is a lithium ion battery can increase the charge / discharge capacity. However, the battery cell can use all the other cylindrical batteries which can be charged, such as a nickel metal hydride battery, instead of the lithium ion battery.

  The intermediate connection member 30 is a U-bent metal plate in a state in which a flat plate is bent in a U-shape, and is connected in a straight line to the U-bent metal plates on both sides and arranged in two stages. 1 electrode is welded and connected. The intermediate connection member 30 connects the battery cells 1 in the same row in parallel and connects the battery cells 1 connected in a straight line in series. The battery pack 100 of FIG. 2 has six battery modules 2 arranged in one stage. Therefore, the intermediate connecting member 30 is first welded with 6 battery cells 1 on each side, 12 battery cells 1 in total, and then U-curved at the center so that the 6 battery cells 1 are connected in parallel. While being connected, battery cells 1 connected in a straight line are connected in series to form a battery module 2. Further, the intermediate connection member 30 is provided with a connection tab 31 projecting from one end for connection to the circuit board 40. The connection tab 31 is connected to the voltage detection circuit of the circuit board 40.

  The intermediate connection member 30 connects the battery cells 1 at the same stage in parallel, and further connects the battery cells 1 connected in a straight line in series. Therefore, the intermediate connection member 30 is connected in a straight line by the intermediate connection member 30 at the same step. The plurality of battery modules 2 disposed in the are connected to each other via an intermediate connecting member 30. Therefore, the battery modules 2 connected by the intermediate connection member 30 become the battery blocks 4 connected to each other. The battery block 4 in FIG. 2 connects six battery cells 1 in parallel with an intermediate connecting member 30. Each battery module 2 has five battery cells 1 connected in series in a straight line, and the six battery modules 2 constitute a battery block 4. Further, in the battery pack 100, two battery blocks 4 are arranged on both surfaces of the separator 60, and each battery module 2 is arranged in two stages.

The battery block 4 arranged in two stages has an output connecting member 10 connected to one end thereof. The output connecting member 10 is composed of a thin metal plate lead plate 11 which is directly welded to the battery electrode and a thick metal plate metal plate 20 connected to the lead plate 11.
(Lead plate 11)

  The lead plate 11 is a metal plate thinner than the metal plate 20, and is formed into a shape in which a cylindrical peripheral wall 13 is provided around a welding surface 12 welded to the battery electrode. The lead plate 11 is preferably a nickel or nickel alloy metal plate or a metal plate having a nickel plated surface. The metal plate used for the lead plate 11 is a metal plate thicker than 0.2 mm and thinner than 0.8 mm. This is because an excessively thick metal plate cannot be stably and reliably welded to the battery electrode.

  The lead plate 11 in FIG. 5 has a welding surface 12 in a disc shape and a cylindrical peripheral wall 13 in a cylindrical shape. The welding surface 12 is provided with a slit 14. The welding surface 12 can be resistance-welded by pressing spot welding electrodes on both sides of the slit 14 to reduce reactive current. Since the welding surface 12 can be resistance welded by a method such as spot welding or laser welding, it is not always necessary to provide a slit. This is because laser welding can weld the welding surface 12 having no slit to the electrode.

  The lead plate 11 in FIG. 6 is tapered so that the tip of the cylindrical peripheral wall 13 becomes narrow. The cylindrical peripheral wall 13 can be smoothly inserted into the through hole 21 opened in the metal plate 20. In particular, the structure in which the outer diameter of the cylindrical peripheral wall 13 is made smaller than the inner diameter of the through hole 21, the cylindrical peripheral wall 13 is press-fitted into the through hole 21, and the lead plate 11 is electrically connected to the metal plate 20 has a tip portion. It can be smoothly inserted into the through hole 21 as a tapered shape. The lead plate 11 that press-fits the cylindrical peripheral wall 13 into the through hole 21 and is electrically connected can be fixed while the lead plate 11 is connected to the metal plate 20 in the simplest manner. Moreover, in order to implement | achieve a taper shape, an internal diameter can be narrowed as it goes to a front-end | tip, and the periphery of a front-end | tip part can be chamfered.

Further, the lead plate 11 shown in FIGS. 5 and 6 is provided with a flange 15 protruding outward at the opening edge of the cylindrical peripheral wall 13. The lead plate 11 in FIG. 6 has a cylindrical peripheral wall 13 in a cylindrical shape and a flange 15 in a disk shape. In the lead plate 11, the cylindrical peripheral wall 13 is inserted into the through hole 21 until the flange 15 is brought into close contact with the surface of the metal plate 20. In other words, since the flange 15 serves as a stopper for inserting the cylindrical peripheral wall 13 into the through hole 21, the cylindrical peripheral wall 13 can be easily inserted into a fixed position of the through hole 21. Further, since the flange 15 contacts the surface of the metal plate 20, the flange 15 can be spot welded, soldered, or brazed to the surface of the metal plate 20.
(Metal plate 20)

  The metal plate 20 is fixed to the edge of the battery block 4. One end of the outer shape of the metal plate 20 is bent in an L shape, and a connection tab 22 for connecting to the circuit board 40 is formed. The metal plate 20 is a metal plate that is thicker than the lead plate 11, and is a metal plate that has low electrical resistance and excellent heat conduction. Copper or copper alloy is used for the metal plate 20. Moreover, the metal plate 20 is thicker than 1 mm, and a metal plate thinner than 5 mm is used. Increasing the thickness of the metal plate 20 can reduce the electrical resistance and improve the heat conduction. However, since the metal plate 20 that is too thick becomes heavy, the thickness is set to a thickness that can reduce the voltage drop at the maximum current while the lead plate 11 is inserted into the through hole 21 and securely fixed.

  The metal plate 20 has a through hole 21 at a position where the lead plate 11 is connected. The through hole 21 is an inner shape into which the cylindrical peripheral wall 13 of the lead plate 11 can be inserted, and the through hole 21 to which the cylindrical peripheral wall 13 is press-fitted and electrically connected and fixed is slightly smaller than the outer diameter of the cylindrical peripheral wall 13. For example, the inner diameter is 0.1 mm to 0.3 mm smaller than the outer diameter of the cylindrical peripheral wall 13. The through-hole 21 can be fixed in a state in which the cylindrical peripheral wall 13 is press-fitted and cannot be removed, and can be electrically connected with a small contact resistance by elastically pressing the cylindrical peripheral wall 13 against the inner surface of the through-hole 21. In the metal plate for electrically connecting the flange 15 of the lead plate 11 by welding, soldering, brazing, or the like, the inner shape of the through hole 21 is equal to or slightly larger than the outer shape of the cylindrical peripheral wall 13. The shape can be smoothly inserted.

  The output connecting member 10 having the above-described structure is formed by press-fitting the lead plate 11 into the metal plate 20 or fixing the lead plate 11 by welding, soldering, brazing, or the like, and then welding the lead plate 11 to the battery electrode. And fix. However, after the lead plate 11 is first welded to the electrode of the battery, the lead plate 11 can be inserted into the through hole 21 of the metal plate 20 and connected.

  The connecting member 10 for output composed of the lead plate 11 and the metal plate 20 is connected to the circuit board 40 by connecting the edges of the battery modules 2 in parallel. The metal plate 20 is connected to one end of all the battery modules 2 arranged on the same stage, that is, the battery modules 2 constituting the same battery block 4. In the example of FIG. 2, in order to connect the two battery blocks 4, positive and negative metal plates 20 are prepared. On the other hand, an intermediate lead plate 32 is connected to the end opposite to the side where the metal plate 20 is connected to the battery module 2.

Further, the metal plate 20 serves as an output terminal by connecting the battery modules 2 constituting the battery block 4, that is, the battery modules 2 at the same stage in parallel, and connecting the end of the battery module 2 to the circuit board 40. The metal plate 20 protrudes from a portion connected to the battery module 2 and is provided with a connection tab 22 connected to the circuit board 40. One of the two metal plates 20 connected to the two battery blocks 4 serves as a positive output terminal, and the other serves as a negative output terminal.
(Intermediate lead plate 32)

The intermediate lead plate 32 connects the battery modules 2 constituting the battery blocks 4 arranged in each stage in parallel, and connects two sets of battery blocks 4 arranged in two stages in series. The intermediate lead plate 32 is made of one metal plate, is on the side opposite to the metal plate 20, is connected to the end of all the battery modules 2, connects the two battery blocks 4 in series, and is the same Stage battery modules 2 are connected in parallel. The intermediate lead plate 32 is also provided with a projecting tab 33 protruding so as to input the voltage of the battery cell 1 to the circuit board 40, and the connection tab 33 is connected to the voltage detection circuit of the circuit board 40. Since the intermediate lead plate 32 is a single metal plate and connects two sets of battery blocks 4, the two sets of battery blocks 4 are connected to each other with the separator 60 sandwiched between them. It becomes a state.
(Separator 60)

The separator 60 is made of an insulating material such as plastic and is disposed between the battery modules 2 disposed in a plurality of rows and two stages to insulate the two-stage battery blocks 4. Since the separator 60 insulates the battery blocks 4 in two stages, the outer shape of the separator 60 is a quadrangle that is the outer shape of the battery block 4. That is, the separator 60 is equal in length and width to the battery block 4. The separator 60 in the figure is entirely planar. However, although not shown, the separator can be provided with fitting grooves (or curved grooves) along the cylindrical battery on both sides. The separator can be arranged at a fixed position by guiding the battery module into the fitting groove. For example, a separator that arranges battery blocks connecting six rows of battery modules in parallel on the same plane can be provided with six rows of fitting grooves on both sides, and each battery module can be placed in a fixed position. This separator can be connected to each other by, for example, adhering the battery module via a double-sided adhesive tape (not shown) and arranging the two-stage battery blocks in place.
(Circuit board 40)

  A circuit board 40 is disposed on the side edge of the separator 60. The circuit board 40 is disposed at a fixed position on the side edge of the separator 60 via the board holder 42. The substrate holder 42 is formed by molding an insulating material such as plastic. 3 is provided with two rows of guide grooves 44 for guiding the battery modules 2 arranged in two stages on the surface facing the battery block 4. The substrate holder 42 can be arranged so as not to be displaced with respect to the two-stage battery block 4 by guiding the two-stage battery module 2 to the guide groove 44. Further, the substrate holder 42 is provided with a peripheral wall 46 for disposing the circuit board 40 at a fixed position on the outer surface opposite to the surface facing the battery block 4. The circuit board 40 is placed inside the peripheral wall 46 and disposed at a fixed position. Further, the substrate holder 42 of FIGS. 2 and 3 opens through holes 45 through the connection tabs 31 of the intermediate connection member 30 and the connection tabs 33 of the intermediate lead plate 32 on both sides of the surface facing the battery block 4. Provided. The substrate holder 42 in the figure is a side edge portion of the guide groove 44 and approaches the peripheral wall 46 to open a through hole 45. The circuit board 40 is provided with a connection recess 41 for guiding the connection tabs 31 and 33 on the outer periphery facing the through hole 45 of the substrate holder 42. The connection tab 31 of the intermediate connection member 30 and the connection tab 33 of the intermediate lead plate 32 are inserted into the through hole 45 of the substrate holder 42 and guided to the connection recess 41 of the circuit board 40 to be soldered to the circuit board 40. Connected. Further, the illustrated substrate holder 42 is provided with a support rib 48 that protrudes from the inner surface of the peripheral wall 46 to support the outer periphery of the circuit board 40 disposed inside the peripheral wall 46. The illustrated support ribs 48 are provided on both sides of the through hole 45. The support rib 48 supports the circuit board 40 connected to the connection tabs 31 and 33 in the connection recess 41 at a fixed position.

  The substrate holder 42 has a posture in which the circuit substrate 40 is perpendicular to both surfaces of the separator 60 and extends in the longitudinal direction of the battery module 2, and the circuit substrate 40 is disposed so as to protrude from both surfaces of the separator 60. The outer case 50 is stored in a fixed position.

  The circuit board 40 is preferably substantially equal to the length of the battery module 2 and is connected to two sets of battery blocks 4 arranged in two stages and an intermediate connection material 30 and an output connection material 10 (metal). The width is such that the connection tabs 31 and 22 of the plate 20) can be connected. The circuit board 40 of FIG. 2 is substantially equal to the width of the two-stage battery block 4. The circuit board 40 is mounted with a voltage detection circuit and a protection circuit that detect the voltages of all the battery cells 1 and control charging / discharging of the batteries. The battery pack 100 of FIG. 2 has five battery cells 1 connected in series to one battery module 2, and further, the upper and lower battery modules 2 are connected in series with an intermediate lead plate 32, so that Ten battery cells 1 are connected in series. Therefore, the voltage detection circuit detects the voltages of the ten battery cells 1 connected in series with each other. Ten battery cells 1 connected in series with each other have six battery cells 1 connected in parallel, but the voltage of the battery cells 1 connected in parallel with each other is the same voltage. The voltage detection circuit can detect the voltages of all the battery cells 1 by detecting the voltages of the battery cells 1. The voltage of each battery cell 1 is input to the voltage detection circuit via the intermediate connection member 30, the intermediate lead plate 32, and the output connection member 10.

The connection member made of the output connection member 10 and the intermediate connection member 30 is arranged in parallel to each other and connected to the circuit board 40. The output connection member 10 and the intermediate lead plate 32 input the voltage at both ends of the battery module 2 to the voltage detection circuit, and the intermediate connection member 30 outputs the voltage at the connection point between the battery cells 1 constituting the battery module 2. Input to the voltage detection circuit. The voltage of each battery cell 1 is input to the voltage detection circuit via the output connection member 10, the intermediate lead plate 32, and the intermediate connection member 30. Therefore, the output connection member 10, the intermediate lead plate 32, and the intermediate connection member 30 input the voltage of each battery cell 1 to the voltage detection circuit and connect all the battery cells 1 in parallel and in series. The connection material composed of the output connection material 10, the intermediate lead plate 32, and the intermediate connection material 30 is a metal plate excellent in heat conduction. The intermediate connection member 30 is connected to both ends of all the battery cells 1 arranged in the same stage, connects the battery cells 1 in the same stage in parallel, and further thermally couples the battery cells 1 in the same stage. As a state, it also functions to reduce the temperature difference of the battery cell 1.
(Exterior case 50)

On the other hand, the outer case 50 that houses the battery block 4 is made of metal, is made of aluminum, has an opposing surface parallel to the separator 60 formed into a curved shape along the surface of the battery modules 2 in a plurality of rows and two stages, and the inner surface is a battery cell. The surface of 1 is brought into contact with the heat-bonded state. The outer case 50 includes a bottomed cylindrical main body case 51 having a curved surface and a lid case 52 that closes one end opening of the main body case 51. The main body case 51 is manufactured by forging aluminum. The main body case can also be opened at both ends. In this case, the lid case is fixed to the main body case so as to close the openings at both ends. This body case is manufactured by extruding aluminum. The main body case 51 of FIG. 2 has a facing shape curved along the cylindrical battery cell, and further, one side surface is curved along the cylindrical battery cell, and is the opposite side surface with the circuit board 40. The opposing surface is formed in a flat shape. Thereby, it can be set as the shape which can arrange | position the board | substrate holder 42 easily. In addition, as shown in the modification of FIG. 4, the exterior case 50 can dissipate heat more effectively by providing heat radiation fins 53 on the surface thereof.
(Insulation plate 55)

  In the outer case 50, an insulating plate 55 is disposed between the inner surface of the lid case 52 and the output connection member 10. The insulating plate 55 prevents the output connecting member 10 and the intermediate lead plate 32 from coming into contact with the outer case 50 and short-circuiting.

The battery pack 100 described above is assembled in the following steps.
(1) A plurality of battery cells 1 are connected in parallel and in series via an intermediate connection member 30 to form a battery block 4.
(2) Two sets of battery blocks 4 are arranged on both sides of the separator 60, and the connection member 10 for output and the intermediate lead plate 32 are connected to the battery block 4.
(3) The circuit board 40 is connected to the battery block 4 connected in two stages via the substrate holder 42 to form a battery assembly.
(4) The battery assembly is inserted into the main body case 51 of the outer case 50. At this time, the outer peripheral surface of the battery assembly is covered with an insulating sheet (not shown) to insulate the plurality of battery cells 1 and the connecting material from the outer case 50. As this insulating sheet, a sheet excellent in heat conduction can be used. However, the outer case can be insulated from the battery assembly by applying an insulating paint on the inner surface. An insulating plate 55 is disposed outside the connecting member 10 for output of the battery assembly inserted into the main body case 51 and the intermediate lead plate 32, and the lid case 52 is fixed to the opening of the main body case 51. The output connection member 10 is pulled out from the outer case 50 to become positive and negative output terminals.

  The battery pack of the present invention is suitably used as a power source for electric equipment used outdoors, particularly electric bicycles and electric motorcycles.

DESCRIPTION OF SYMBOLS 100 ... Battery pack 1 ... Battery cell 2 ... Battery module 4 ... Battery block 10 ... Output connection material 11 ... Lead plate 12 ... Welding surface 13 ... Cylindrical peripheral wall 14 ... Slit 15 ... Collar 20 ... Metal plate 21 ... Through-hole 22 ... Connection tab 30 ... Intermediate connection material 31 ... Connection tab 32 ... Intermediate lead plate 33 ... Connection tab 40 ... Circuit board 41 ... Connection recess 42 ... Substrate holder 44 ... Guide groove 45 ... Through hole 46 ... Peripheral wall 48 ... Support rib 50 ... Exterior case 51 ... Body case 52 ... Lid case 53 ... Radiating fin 55 ... Insulating plate 60 ... Separator

Claims (8)

A battery pack having a plurality of battery cells and an output connecting material electrically connected to the electrodes of the battery cells,
The output connecting material is:
A lead plate welded to the electrode of the battery cell;
A metal plate connected to the lead plate;
With
The lead plate is formed of a metal plate thinner than the metal plate,
A welding surface welded to the electrode of the battery cell;
It is molded into a shape comprising a cylindrical peripheral wall formed around the weld surface,
The metal plate is provided with a through hole into which the cylindrical peripheral wall of the lead plate can be inserted and fitted,
The lead plate is inserted into the through hole of the metal plate with the cylindrical peripheral wall of the lead plate contacting the inner surface of the through hole of the metal plate, and the lead plate is connected to the metal plate. A battery pack characterized by   The battery pack according to claim 1, wherein a cylindrical peripheral wall of a lead plate is press-fitted into a through hole of the metal plate and connected to the metal plate.   2. The battery pack according to claim 1, wherein the lead plate has a disk-shaped weld surface and a cylindrical peripheral wall.   The battery pack according to any one of claims 1 to 3, wherein the lead plate is provided with a flange protruding outward at an opening edge of the cylindrical peripheral wall.   The battery pack according to claim 4, wherein the flange of the lead plate is fixed to the metal plate by welding, soldering, or brazing.   The battery pack according to any one of claims 1 to 5, wherein the lead plate is a metal plate made of nickel or a nickel alloy.   The battery pack according to any one of claims 1 to 6, wherein the metal plate is a metal plate made of copper or a copper alloy. The lead plate is a metal plate thicker than 0.2 mm and thinner than 0.8 mm;
The battery pack according to claim 1, wherein the metal plate is a metal plate that is thicker than 1 mm and thinner than 5 mm.

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