JP5384156B2 - Battery pack - Google Patents

Description

  The present invention mainly relates to a battery pack used for a high-output power source such as an electric bike or an assist bicycle assisted by a motor.

  A high-power 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. A battery pack formed by connecting a large number of batteries in series and in parallel incorporates a large number of batteries. Therefore, it is important to cool each battery efficiently to reduce the temperature rise. It is also important to reduce the temperature difference between the batteries. This is because the temperature difference causes the electric characteristics of the battery to be unbalanced, and the specific battery is rapidly deteriorated to shorten the life of the entire battery pack.

  In order to efficiently cool a plurality of batteries stored therein, a battery pack having an outer case made of aluminum and having a shape along the surface of the battery has been developed. (See Patent Documents 1 and 2)

JP 2001-307784 A JP 2002-216726 A

  A battery pack having an outer case made of aluminum and having a shape along the surface of the battery can efficiently dissipate the heat of the battery from the outer case to the outside. However, as described in Patent Document 2, a circuit board is housed in an outer case, a battery is a battery module in which a plurality of battery cells are linearly connected, and a plurality of battery modules are housed in the outer case. However, it is difficult to reduce the temperature difference between all the battery cells. For example, a battery cell facing the circuit board has a worse heat dissipation than a battery cell not facing the circuit board. Further, in a battery pack in which a large number of battery cells are connected in a straight line and stored as a battery module in an outer case, it is difficult to reduce the temperature difference between the battery cells. This is because the battery cells disposed on both sides are efficiently cooled, and the cooling of the battery cells in the center is deteriorated.

  Further, in a battery pack in which a large number of battery cells are connected in series or in parallel, it is important to charge and discharge each battery cell equally. This is because the imbalance between charging and discharging shortens the battery life. In order to eliminate the unbalance of each battery cell, the battery pack that detects the voltage of each battery and controls charge / discharge prevents the specific battery cell from deteriorating and prolongs the life of the battery pack. it can. In a battery pack that realizes this, a circuit board on which a voltage detection circuit that detects the voltages of all battery cells is mounted is housed in an outer case. In this battery pack, positive and negative electrodes of each battery cell are connected to a circuit board by a lead plate. Although this battery pack has a feature capable of preventing the deterioration of a specific battery cell, there is a drawback that the wiring of the lead wire is complicated because the positive and negative electrodes of all the battery cells are connected to the circuit board.

  The present invention has been developed for the purpose of solving all the above drawbacks at once. An important object of the present invention is to connect a large number of battery cells in series and in parallel and store them in an outer case together with a circuit board, while reducing the temperature difference of each battery cell and extending the overall life, And it is providing the battery pack which can simplify the wiring for detecting the voltage of all the battery cells.

Means for Solving the Problems and Effects of the Invention

  The battery pack according to the present invention includes a plurality of battery modules 2 formed by linearly connecting battery cells 1 formed of a plurality of cylindrical batteries, a lead plate 3 formed by connecting the battery cells 1 in series and in parallel, A circuit board 40 mounted with a voltage detection circuit that detects the voltage of each battery cell 1 connected to the positive and negative electrodes of each battery cell 1 via the lead plate 3, and the battery module 2 and the circuit board 40 are accommodated. The outer case 50 is provided. Each battery module 2 has the same number of battery cells 1 connected in a straight line, and is arranged in a plurality of rows and two stages in a posture parallel to each other, and a separator between the battery modules 2 in the plurality of rows and two stages. 60 is disposed. The outer case 50 is made of metal, and has an opposing surface parallel to the separator 60 in a curved shape along the surface of the battery modules 2 in a plurality of rows and two stages, and is brought into contact with the surface of the battery module 2. Further, the circuit board 40 is positioned on the side edge of the separator 60 and is orthogonal to both surfaces of the separator 60 and extends in the longitudinal direction of the battery module 2, and extends outside the separator 60. 50. Further, the lead plate 3 includes a main lead plate 9 that connects both ends of each battery module 2 in parallel and connects to the circuit board 40, and a connection portion of a plurality of battery cells 1 that are linearly connected to the circuit board. 40 and a sub lead plate 30 connected to 40. The main lead plate 9 is connected to the positive and negative output lead plates 10 connected to one end of all the battery modules 2 arranged on the same stage and the opposite end of all the battery modules 2. It consists of one intermediate lead plate 32. The sub lead plate 30 is parallel to the main lead plate 9 and is connected to connection points of all the battery modules 2 arranged on the same stage. In the battery pack, the main lead plate 9 and the sub lead plate 30 connect the electrodes of all the battery cells 1 to the circuit board 40.

  The above battery pack can be connected to a large number of battery cells in series and in parallel with the circuit board and housed in the outer case, reducing the temperature difference between the battery cells and extending the overall life, There is a feature that wiring for detecting the voltage of all battery cells can be simplified. That is, the battery pack described above is arranged in a plurality of rows and two stages with a separator between a plurality of battery modules connecting a plurality of battery cells in a straight line, and the exterior case is made of metal. The opposite surface is in a curved shape along the surface of the battery module and contacts the surface of the battery module. Further, the circuit board is arranged on one side of the separator in a unique posture. Further, both ends of the battery module are attached to the circuit board. Each battery cell is connected by a main lead plate to be connected and a sub lead plate for connecting a plurality of battery cell connecting portions, and the main lead plate is a pair of output lead plates connected to one end of the battery module, and the battery It is composed of one intermediate lead plate connected to the opposite side of the module, and the sub lead plate is arranged in the same row in a posture parallel to the main lead plate. Connected to the connection point of all the battery modules you are, because connecting the electrodes of all the battery cells in the circuit board in the main lead plate and sub-lead plate. In the battery pack having this structure, each battery cell effectively dissipates heat in the exterior case. However, the outer case alone cannot radiate heat so that all the battery cells do not have a temperature difference, but the temperature difference of each battery cell is the lead plate connected to all the battery cells in order to detect the voltage of the battery cells. Can be reduced by heat conduction. That is, by arranging the lead plate with a unique structure, it is possible to realize a feature that can reduce the temperature difference while detecting the voltage of each battery cell.

In the battery pack of the present invention, a plurality of battery modules 2 are arranged at each stage to form a battery block 4, and an output lead plate 10 is connected to an end of the battery module 2 constituting the battery block 4, and an intermediate lead plate 32 can be connected to the end of the battery module 2 constituting the two-stage battery block 4, and the sub lead plate 30 can be connected to the plurality of battery cells 1 constituting the battery block 4.
The above battery pack can cool the battery module efficiently while reducing the temperature difference between all the battery cells between the outer case and the lead plate.

In the battery pack of the present invention, the radiation fins 53 can be provided on the surface of the outer case 50.
This battery pack can radiate heat from the outer case more efficiently with the radiation fins, and the temperature rise of the built-in battery module can be reduced.

The battery pack of the present invention can accommodate the circuit board 40 in the exterior case 50 through the board holder 42.
In this battery pack, the circuit board can be arranged at an accurate position of the outer case with the board holder.

In the battery pack of the present invention, the battery cell can be a lithium ion battery.
This battery pack is characterized by being able to charge and discharge while reducing the unbalance of the lithium ion battery.

1 is an external perspective view of a battery pack according to an embodiment of the present invention. It is a disassembled perspective view of the battery pack shown in FIG. It is a cross-sectional view of the battery pack shown in FIG. It is a front view of an output lead board. FIG. 5 is a partially enlarged VV sectional view of the output lead plate shown in FIG. 4. It is a perspective view of a connection lead board. FIG. 7 is a plan view of the connection lead plate shown in FIG. 6. FIG. 7 is a front view of the connection lead plate shown in FIG. 6. It is a cross-sectional view of a battery pack according to another embodiment of the present invention.

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

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

  A battery pack 100 shown in FIGS. 1 to 3 includes a plurality of battery modules 2 formed by linearly connecting battery cells 1 made up of a plurality of cylindrical batteries, and leads formed by connecting the battery cells 1 in series and in parallel. A circuit board 40 on which a voltage detection circuit for detecting the voltage of each battery cell 1 connected to the positive and negative electrodes of each battery cell 1 via the lead plate 3 is mounted; An exterior case 50 that houses the substrate 40 is provided. Each battery module 2 has the same number of battery cells 1 connected in a straight line, and is arranged in a plurality of rows and two stages in a posture parallel to each other, and a separator between the battery modules 2 in the plurality of rows and two stages. 60 is disposed. In addition, the lead plate 3 includes a main lead plate 9 that connects both ends of each battery module 2 in parallel and connects to the circuit board 40, and a connection portion between the plurality of battery cells 1 that are linearly connected to the circuit board. 40 and a sub lead plate 30 connected to 40.

  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 a sub lead plate 30 at a connection point between a plurality of battery cells 1 and welding the sub lead plate 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. The battery module 2 can connect fewer than five battery cells 1 or more than five battery cells 1 in a straight line. The battery module 2 adjusts the voltage by the number of battery cells 1 connected in a straight line. Since the battery pack of the present invention connects two sets of battery modules 2 arranged in two stages in series, the output voltage is twice the voltage of the battery module 2. Therefore, in the battery pack in which the battery module 2 is composed of five battery cells 1, ten battery cells 1 are connected in series. Therefore, in a battery pack in which a lithium ion battery having a rated voltage of 3.6V 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 36V. It becomes. The battery pack 100 in which the battery cell 1 is a lithium ion battery can increase the charge / discharge capacity. However, all the other cylindrical batteries which can be charged, such as a nickel metal hydride battery, can be used for the battery cell 1 instead of a lithium ion battery.

  The sub-lead plate 30 is a U-bent metal plate in a state in which a flat plate is bent in a U-shape, and the electrodes of the battery cells 1 that are linearly connected to the U-bent metal plates are connected by welding. doing. The sub lead plate 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. In the illustrated battery pack, six battery modules 2 are arranged in one stage. Accordingly, the sub-lead plate 30 is welded to each of the six battery cells 1 on both sides, and a total of 12 battery cells 1 are welded. The battery cells 1 to be connected are connected in series. Furthermore, the sub lead plate 30 is provided with a connection tab 31 for connecting to the circuit board 40 so as to protrude from one end. The connection tab 31 is connected to the voltage detection circuit of the circuit board 40.

  Since the sub lead plate 30 connects the battery cells 1 in the same stage in parallel and further connects the battery cells 1 connected in a straight line in series, the sub lead plate 30 is connected in a straight line by the sub lead plate 30 and arranged in the same stage. The plurality of battery modules 2 are connected to each other through the sub lead plate 30. Therefore, the battery modules 2 connected by the sub lead plate 30 become battery blocks 4 connected to each other. The battery block 4 in FIG. 2 connects six battery cells 1 in parallel with the sub lead plate 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 sides of the separator 60, and the battery modules 2 are arranged in two stages.

  Battery blocks 4 arranged in two stages have main lead plates 9 connected to both ends thereof. The main lead plate 9 is connected to the circuit board 40 by connecting both ends of each battery module 2 in parallel. The main lead plate 9 includes all battery modules 2 arranged in the same stage, that is, positive and negative output lead plates 10 connected to one end of the battery module 2 constituting the same battery block 4, and all the batteries. It consists of an intermediate lead plate 32 connected to the opposite end of the module 2.

  As shown in FIGS. 4 to 8, the output lead plate 10 is formed by connecting the connection lead plate 11 to a thin metal plate connection lead plate 11 that is directly welded to the electrode of the battery cell 1. The metal plate 20 is a thick metal plate.

  As shown in FIGS. 6 to 8, the connection lead plate 11 is a metal plate thinner than the metal plate 20, and a cylindrical peripheral wall 13 is provided around the welding surface 12 welded to the electrode of the battery cell 1. Molded into a shape. The connection lead plate 11 is preferably a nickel or nickel alloy metal plate or a metal plate having a nickel plated surface. Further, the metal plate used for the connection 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 connecting lead plate 11 in the figure 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 connecting lead plate 11 shown in the figure 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 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 and the cylindrical peripheral wall 13 is press-fitted into the through-hole 21 to electrically connect the connection lead plate 11 to the metal plate 20 is Can be smoothly inserted into the through hole 21. The connection lead plate 11 that press-fits the cylindrical peripheral wall 13 into the through-hole 21 and is electrically connected can be fixed while connecting the connection lead plate 11 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 connecting lead plate 11 shown in the drawing is provided with a flange 15 protruding outward at the opening edge of the cylindrical peripheral wall 13. The connecting lead plate 11 shown in the figure has a cylindrical peripheral wall 13 in a cylindrical shape and a flange 15 in a disk shape. In this connection 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.

  The metal plate 20 is a metal plate thicker than the connection lead plate 11, and a metal plate having a small electric resistance and excellent heat conduction is used. 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 connection lead plate 11 is inserted into the through hole 21 and securely fixed.

  The metal plate 20 is provided with a through hole 21 at a position where the connection lead plate 11 is connected. The through hole 21 is an inner shape into which the cylindrical peripheral wall 13 of the connection lead plate 11 can be inserted. The through hole 21 that press-fits the cylindrical peripheral wall 13 to be 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 connecting 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. Thus, the shape can be smoothly inserted.

  In the output lead plate 10 having the above configuration, the connection lead plate 11 is press-fitted into the metal plate 20 or fixed by welding, soldering, brazing, or the like, and then the connection lead plate 11 is attached to the electrode of the battery cell 1. Fix by welding. However, after the connection lead plate is first welded to the electrode of the battery cell, the connection lead plate can be inserted into the through hole of the metal plate and connected.

  The output lead plate 10 composed of the connection lead plate 11 and the metal plate 20 connects the edge of each battery module 2 in parallel to connect to the circuit board 40. The output lead plate 10 of FIG. 5 has one end of a metal plate 20 bent into an L shape and is provided with a connection tab 22 for connection 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. The output lead plate 10 is connected to one end of all battery modules 2 arranged in the same stage, that is, the battery modules 2 constituting the same battery block 4. Further, the output lead plate 10 connects the battery modules 2 at the same stage in parallel to serve as an output terminal, and connects the end of the battery module 2 to the circuit board 40. One of the pair of output lead plates 10 connected to the two battery blocks 4 is a plus-side output terminal, and the other is a minus-side output terminal.

  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 a single metal plate, is on the side opposite to the output lead plate 10 and is connected to the ends of all the battery modules 2 to connect the two battery blocks 4 in series. The battery modules 2 at the same stage 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.

  The separator 60 is made of an insulating material 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 FIG. 2 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.

  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 manufactured 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 module 2. The circuit board 40 is placed inside the peripheral wall 46 and disposed at a fixed position. Further, the substrate holder 42 in FIG. 2 and FIG. 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 sub lead plate 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 the connection tabs 31 and 22 of the main lead board 9. , 33 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 are connected in parallel with six of each of the battery cells 1, but the voltage of the battery cells 1 connected in parallel 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 sub lead plate 30 and the main lead plate 9.

  The lead plate 3 including the main lead plate 9 and the sub lead plate 30 is disposed in parallel to each other and connected to the circuit board 40. The main lead plate 9 inputs the voltage across the battery module 2 to the voltage detection circuit, and the sub lead plate 30 inputs the voltage at the connection point between the battery cells 1 constituting the battery module 2 to the voltage detection circuit. The voltage of each battery cell 1 is input to the voltage detection circuit via the main lead plate 9 and the sub lead plate 30. Therefore, the main lead plate 9 and the sub lead plate 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 lead plate 3 including the main lead plate 9 and the sub lead plate 30 is a metal plate excellent in heat conduction. The lead plate 3 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 connects the battery cells 1 in the same stage in a thermally coupled state. As a result, the temperature difference of the battery cell 1 is reduced.

  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 curved shape along the cylindrical battery cell on the opposite surface, and a curved shape along the cylindrical battery cell on one side. 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. 9, the exterior case 50 can also radiate heat more effectively by providing heat radiation fins 53 on the surface thereof.

  In the outer case 50, an insulating plate 55 is disposed between the inner surface of the lid case 52 and the main lead plate 9. The insulating plate 55 prevents the main lead plate 9 from coming into contact with the exterior 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 the sub lead plate 30 to form a battery block 4.
(2) Two sets of battery blocks 4 are arranged on both surfaces of the separator 60, and the main lead plate 9 is 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 to insulate the plurality of battery cells 1 and the lead plate 3 from the outer case 50. As this insulating sheet, a sheet excellent in heat conduction can be used. However, the outer case 50 can be insulated from the battery assembly by applying an insulating paint on the inner surface. An insulating plate 55 is disposed outside the main lead plate 9 of the battery assembly inserted into the main body case 51, and the lid case 52 is fixed to the opening of the main body case 51. The output lead plate 10 of the main lead plate 9 is pulled out from the outer case 50 to become a positive / negative output terminal.

  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 1 ... Battery cell 2 ... Battery module 3 ... Lead board 4 ... Battery block 9 ... Main lead board 10 ... Output lead board 11 ... Connection lead board 12 ... Welding surface 13 ... Cylindrical peripheral wall 14 ... Slit 15 ... Collar 20 ... Metal plate DESCRIPTION OF SYMBOLS 21 ... Through-hole 22 ... Connection tab 30 ... Sub lead board 31 ... Connection tab 32 ... Intermediate lead board 33 ... Connection tab 40 ... Circuit board 41 ... Connection recessed part 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 ... Radiation fin 55 ... Insulating plate 60 ... Separator 100 ... Battery pack

Claims (5)

A plurality of battery modules (2) formed by linearly connecting battery cells (1) made of a plurality of cylindrical batteries, a lead plate (3) formed by connecting battery cells (1) in series and in parallel, A circuit board (40) mounted with a voltage detection circuit that detects the voltage of each battery cell (1) connected to the positive and negative electrodes of each battery cell (1) via the lead plate (3), and a battery A battery pack comprising a module (2) and an outer case (50) containing a circuit board (40),
Each battery module (2) has the same number of battery cells (1) connected in a straight line, and is arranged in a plurality of rows and two stages in a posture parallel to each other. A separator (60) is arranged between 2)
The outer case (50) is made of metal, and the surface of the battery module (2) is formed such that the facing surface parallel to the separator (60) is curved along the surface of the battery modules (2) in a plurality of rows and two stages. In contact with
Further, the circuit board (40) is positioned on the side edge of the separator (60), orthogonal to both surfaces of the separator (60), and extending in the longitudinal direction of the battery module (2), It is housed in the outer case (50) so as to protrude on both sides of the separator (60),
Furthermore, the lead plate (3) is connected to the main lead plate (9) connected to the circuit board (40) by connecting both ends of each battery module (2) in parallel, and a plurality of the lead plates (3) linearly connected. The sub lead plate (30) is formed by connecting the connection portion of the battery cell (1) to the circuit board (40), and the main lead plate (9) is connected to all the battery modules ( 2) It consists of positive and negative output lead plates (10) connected to one end of the battery and one intermediate lead plate (32) connected to the opposite end of all battery modules (2).
The sub lead plate (30) is in a posture parallel to the main lead plate (9) and connected to connection points of all the battery modules (2) arranged on the same stage, and the main lead plate ( 9) A battery pack in which the electrodes of all the battery cells (1) are connected to the circuit board (40) by the sub lead plate (30).   A plurality of battery modules (2) are arranged in each stage to form a battery block (4), and the output lead plate (10) is connected to an end of the battery module (2) constituting the battery block (4), The intermediate lead plate (32) is connected to an end of a battery module (2) constituting a two-stage battery block (4), and the sub lead plate (30) further comprises a plurality of batteries constituting the battery block (4). The battery pack according to claim 1, wherein the battery pack is connected to the cell (1).   The battery pack according to claim 1, wherein heat radiation fins (53) are provided on a surface of the outer case (50).   The battery pack according to claim 1, wherein the circuit board (40) is housed in an exterior case (50) through a board holder (42).   The battery pack according to claim 1, wherein the battery cell (1) is a lithium ion battery.

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