JP2013109934A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively protect battery cells parallely connected to each other.SOLUTION: A battery pack comprises: plural battery cells 1; a battery holder 2 for housing the plural battery cells 1; and plural lead plates 5 mounted to the battery holder for parallely connecting the plural battery cells 1. The battery holder is divided into a first battery holder 2A and a second battery holder 2B, and connects the lead plates 5 of the same electric potential to each other via a protective resistance 56 among the lead plates 5 mounted to the first battery holder 2A and the lead plates 5 mounted to the second battery holder 2B. Thereby, even in such a situation that an internal short-circuit occurs to the battery cells 1 parallely connected to each other via the lead plates 5 and a current is concentrated, a current value can be restrained via the protective resistance 56, so as to protect the battery cells 1.

Description

  The present invention relates to a battery pack containing a plurality of rechargeable secondary batteries, for example, a power pack that can be used for a power source for an electric scooter or an assist bicycle.

  A battery pack in which a large number of secondary batteries are connected in series and / or in parallel is used for a power source of an electric scooter, an assist bicycle, or a power supply device of an electric vehicle. The battery pack stores a secondary battery in a resin battery holder, and further stores the battery holder in an insulating outer case.

  In such a battery pack, the output voltage can be increased by increasing the number of battery cells connected in series, and the battery capacity can be increased by increasing the number of battery cells connected in parallel. In particular, in view of the recent demand for higher output, battery packs tend to increase the number of battery cells used.

  On the other hand, in order to monitor abnormality of the battery cell which comprises a battery pack, measuring the voltage of a battery cell is performed. In such a configuration, generally, the cell voltage is detected from the intermediate potential by measuring the potential of the lead plate connecting the battery cells.

  Here, in the configuration in which a large number of battery cells are connected to the lead plate in series and in parallel, the electrical wiring work at the time of assembling the battery pack becomes complicated. Since a large number of battery cells are directly electrically connected, it is conceivable that they are accidentally short-circuited during assembly. In particular, when any one of the battery cells connected in parallel is short-circuited, current concentrates on the battery cell having low resistance, and current from other battery cells flows. Moreover, when battery cells are connected in parallel, the greater the number of parallel cells, the lower the combined resistance of the internal resistances. For this reason, there is a possibility that a large current flows into one battery cell and generates heat. On the other hand, it is conceivable to use a bus bar or the like for safe wiring, but there is a disadvantage that the wiring work increases and the cost also increases.

JP 2007-71632 A JP 2004-31014 A JP 2010-211926 A JP 2010-267405 A JP-A-4-126378

  The present invention has been made in view of such conventional problems. The main objective of this invention is to provide the battery pack which implement | achieved the structure which protects the battery cell connected in parallel at low cost.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a battery pack according to a first aspect of the present invention is attached to a plurality of battery cells 1, a battery holder 2 that houses the plurality of battery cells 1, and the battery holder. A battery pack comprising a plurality of lead plates 5 for connecting the plurality of battery cells 1 in parallel, wherein the battery holder is divided into a first battery holder 2A and a second battery holder 2B; Of the lead plate 5 attached to the first battery holder 2A and the lead plate 5 attached to the second battery holder 2B, the lead plates 5 having the same potential are connected to each other via a protective resistor 56. Can do. As a result, the current value can be suppressed via the protective resistor even if the current concentrates due to an internal short circuit in the battery cells connected in parallel via the lead plate. Can be achieved. Further, the protective resistor is provided not on the output line of the battery pack but on the voltage detection line, so that no loss occurs during normal high voltage output.

  The battery pack according to the second aspect further includes a connection board 55 for electrically connecting the first battery holder 2A and the second battery holder 2B, and the protective resistor 56 is provided on the connection board 55. Can be implemented. Thereby, in the structure which divides | segments a battery holder and connects with a connection board | substrate, it becomes possible to aim at protection of the battery cell connected in parallel by providing a protection resistance in a connection board | substrate.

  Further, in the battery pack according to the third aspect, the protective resistor 56 can be provided every other battery cell 1 connected in parallel to the adjacent parallel battery block. Thereby, it is possible to protect the battery pack while reducing the number of protective resistors without providing protective resistors for each battery cell.

  Furthermore, the battery pack according to the fourth aspect further includes a circuit board 6 on which a protection circuit for monitoring the voltage of the battery cell 1 housed in the first battery holder 2A and the second battery holder 2B is mounted. be able to. Thereby, the voltage of the battery cell of two battery holders can be collectively monitored with one circuit board, the number of circuit components and the number of boards can be reduced, and the apparatus can be reduced in size and cost.

  Furthermore, in the battery pack according to the fifth aspect, the protective resistance 56 can be made substantially equal to the internal resistance of the battery cell 1. As a result, the amount of decrease in the combined resistance of the internal resistance due to the parallel connection of the battery cells can be compensated by the protective resistance connected in series with the battery cells connected in parallel, so that almost normal battery cells are energized. The heat generation can be suppressed to the same level as that of the conventional method, and an advantage that can be dealt with by a normal heat radiation design is obtained.

1 is an exploded perspective view of a battery pack according to Example 1. FIG. It is a perspective view which shows the battery assembly of FIG. FIG. 3 is an exploded perspective view of the battery assembly of FIG. 2. It is the disassembled perspective view which looked at the battery assembly of FIG. 3 from the back diagonally downward. It is a perspective view which shows the state which connected battery holders with the connection board | substrate. It is a circuit diagram of the battery pack which provided the protective resistance between the parallel battery blocks of the same electric potential. It is a schematic cross section which shows the state connected with a connection board | substrate to a 1st battery holder and a 2nd battery holder, respectively. It is a schematic cross section which shows the state which connected the 1st battery holder and the 2nd battery holder to the connection board | substrate of FIG. It is a circuit diagram which shows the battery pack which concerns on a modification. FIG. 6 is an enlarged cross-sectional view illustrating a joint portion between a divided case and a connection substrate in FIG. 5.

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. 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's 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.
Example 1

  FIG. 1 shows an exploded perspective view of a battery pack 100 according to Embodiment 1 of the present invention. The battery pack 100 shown in this figure is mounted on an electric motorcycle and supplies driving power. For this reason, an output connector for supplying electric power to the electric motorcycle is provided. The output connector includes an output terminal that is a high voltage line in which secondary batteries built in the battery pack 100 are connected in series and / or in parallel. A signal terminal for exchanging control signals between the battery pack 100 and the electric motorcycle is also provided separately from the output terminal. Further, the output connector can be provided with a charging terminal for charging the built-in battery cell 1 from the outside. The charging terminal may also be used as the output terminal. The output connector collects these output terminals and / or charge terminals and signal terminals. However, each terminal can be provided in a separate connector without having to put these terminals together in one output connector.

  The battery pack 100 is set at a fixed position of the electric motorcycle and connects the output connector to a receptacle provided on the electric motorcycle. Although an example in which a battery pack is used as a power supply device for an electric motorcycle will be described here, it goes without saying that the present invention is not limited to a power supply device for an electric motorcycle, and can be used as another power supply device. Absent.

  A battery pack 100 shown in FIG. 1 includes a plurality of rechargeable battery cells 1 and a battery holder 2 in which battery storage spaces 34 each storing a plurality of battery cells 1 are individually partitioned. In the illustrated battery pack 100, a battery assembly in which a plurality of battery cells 1 are arranged at fixed positions of a battery holder 2 and connected in series and in parallel is housed in an outer case 4.

In the battery pack 100, the overall shape of the outer case 4 constituting the outer shape is substantially box-shaped. The battery holder is divided into a first battery holder 2A and a second battery holder 2B. Each battery holder is accommodated in an internal space in which an outer case is divided into an upper case and a lower case. Further, a sealing material that is elastically deformed, such as packing, is interposed between the joint surfaces of the upper case and the lower case, so that waterproofing at the joint interface can be achieved.
(Battery assembly)

  The first battery holder 2A and the second battery holder 2B have rectangular shapes that are substantially equal in outer shape except for a connector portion provided on the first battery holder 2A. Here, FIG. 2 shows a perspective view of the battery assembly constituted by the second battery holder 2B, and FIG. 3 and FIG. 4 show exploded perspective views thereof. As shown in these figures, the battery assembly includes a plurality of rechargeable battery cells 1, a second battery holder 2B made of plastic that holds these battery cells 1 arranged in multiple rows and multiple rows, and a second battery holder. A plurality of lead plates 5 that are welded to the end surface electrode 1A of each battery cell 1 held in place by 2B and connect adjacent battery cells 1, and provided on one surface of the second battery holder 2B And a circuit board 6.

As shown in the exploded perspective views of FIGS. 3 and 4, the first battery holder 2 </ b> A and the second battery holder 2 </ b> B are arranged in seven rows in the vertical direction and arranged in 14 rows in the horizontal direction. Yes. That is, 98 battery cells 1 are arranged in a matrix in 7 rows and 14 columns. However, the battery pack of the present invention does not specify the number or arrangement of battery cells in this state. Furthermore, a plurality of battery cells arranged in multiple stages and multiple rows are connected in series and in parallel to form a battery assembly. The battery assembly shown in FIGS. 3 and 4 connects seven battery cells arranged in the same row in parallel, and connects seven battery cells arranged in adjacent rows in series. 14 rows of battery cells are connected in series. That is, the battery assembly shown in the figure has 98 battery cells connected in 7 rows and 14 rows. In this structure, the output current of the battery pack can be increased by connecting a plurality of battery cells in parallel, and the output voltage of the battery pack can be increased by connecting battery cells connected in parallel to each other in series. However, the battery pack of the present invention does not specify the number of battery cells connected in parallel to each other and the number of battery cells connected in series with each other.
(Battery cell 1)

The battery cell 1 is a rechargeable secondary battery. In the illustrated battery pack, the battery cell 1 is a cylindrical battery cell. In this embodiment, a cylindrical lithium ion secondary battery is used as the battery cell 1. The lithium ion secondary battery is suitable for a battery system with a large capacity and a large output. This is because the lithium ion secondary battery can increase its capacity with respect to volume and weight. However, the battery pack of the present invention does not specify a battery as a lithium ion secondary battery, and other rechargeable secondary batteries such as a lithium polymer battery, a nickel metal hydride battery, and a nickel cadmium battery can be used. Furthermore, the outer shape is not limited to a cylindrical shape, and a rectangular battery can be used.
(Battery holder 2)

  The battery holder 2 is divided into two parts, a first battery holder 2A and a second battery holder 2B. The first battery holder 2A and the second battery holder 2B hold a plurality of cylindrical battery cells 1 arranged in a multi-stage multi-row in a posture parallel to each other. As shown in the perspective views of FIG. 3 and FIG. 4, each battery holder 2 is provided with a cylindrical battery storage space 34 that can store the battery cells 1 in multiple rows and columns, and each battery storage space 34 has a battery. Cell 1 is inserted and placed in place. The battery holder 2 is provided with a battery storage space 34 for storing the battery cell 1 so as to open in the axial direction of the battery cell 1. The illustrated battery holder 2 is formed in a shape having a cylindrical battery storage space 34. The battery storage space 34 is formed in an inner shape into which the cylindrical battery cell 1 can be inserted. The second battery holder 2B shown in the figure is provided with 98 battery storage spaces 34 in a matrix of 7 rows and 14 rows so that 98 battery cells 1 can be stored in a predetermined arrangement. Furthermore, the second battery holder 2B opens both ends of the battery storage space 34 on both sides thereof.

  The second battery holder 2B is divided into a first sub holder 2a and a second sub holder 2b in the middle of the longitudinal direction of the cylindrical battery cell 1 (vertical direction in FIGS. 3 and 4). The first sub-holder 2a and the second sub-holder 2b are formed in such a shape that both ends of the battery storage space 34 are opened and the cylindrical battery cell 1 can be inserted. The second battery holder 2B is formed of an insulating member such as plastic. The second battery holder 2B in which plastic is molded into a shape in which the battery housing space 34 is provided can be arranged while accurately positioning the plurality of battery cells 1 by partitioning and arranging the battery cells 1.

The first sub-holder 2 a and the second sub-holder 2 b are connected to each other in a state where both ends of the battery cell 1 are inserted into the battery storage spaces 34, and the battery cells 1 are stored in the respective battery storage spaces 34. The first sub holder 2a and the second sub holder 2b are connected to each other via a set screw. The first sub-holder 2a in the drawing has a screw hole (not shown) for inserting a set screw, and the second sub-holder 2b has a connecting boss into which the set screw is screwed on the opposing surface.
(Projection prevention part 32)

  Further, the second battery holder 2B is integrally formed with an outer end face with a protrusion preventing portion 32 that prevents the end face electrode 1A of the battery cell 1 inserted into the battery storage space 34 from protruding outward from the outer end face. Provided. The protrusion preventing portion 32 exposes the end face electrode 1A of the battery cell 1 inserted into the battery storage space 34 from the outer end face, but the open end of the battery storage space 34 so that the end face electrode 1A does not protrude from the open end. It protrudes inward from the edge and is provided in a state of protruding so as to partially cover the opening of the battery storage space 34.

  The second battery holder 2 </ b> B in FIG. 2 arranges the battery storage spaces 34 in a matrix, and prevents the battery storage spaces 34 from projecting so as to partially overlap the openings of the battery storage spaces 34. The portion 32 is provided in a straight line. The second battery holder 2 </ b> B prevents the protrusion preventing portion 32 from coming into contact with the end face electrode 1 </ b> A of the battery cell 1 inserted through the battery storage space 34 and protruding the end face electrode 1 </ b> A of the battery cell 1 from the outer end face. Further, the protrusion preventing portion 32 also functions as a guide for guiding the lead plate 5 to a fixed position.

The second battery holder 2B exposes the end face electrode 1A of the battery cell 1 from the outer opening of the battery storage space 34 to the outside in a state where the first sub holder 2a and the second sub holder 2b are connected. Lead plate 5 is welded to end face electrode 1A exposed to the outside by a method such as spot welding or laser welding. The second battery holder 2B shown in FIGS. 3 and 4 has the protrusion preventing portions 32 on both surfaces that open both ends of the battery storage space 34, as a guide for disposing the plurality of lead plates 5 away from each other in a fixed position. We are using. The lead plate 5 is guided by the protrusion preventing portion 32 and connected to the end face electrode 1 </ b> A of the battery cell 1. Therefore, the protrusion preventing portion 32 is provided at a position where the lead plate 5 connected to the end face electrode 1A is disposed.
(Lead plate 5)

  As shown in FIGS. 3 and 4, the lead plate 5 is guided by the protrusion preventing portion 32 of the second battery holder 2B, and is connected to the end face electrode 1A of the battery cell 1 by spot welding or laser welding. The battery cells 1 to be connected are connected in series and in parallel. The lead plate 5 connects the battery cells 1 in the same row in parallel and connects the battery cells 1 in adjacent rows in series. The lead plates 5 are arranged at both ends of the battery cells 1 connected in multiple rows, and each row has a first lead plate 5A having a width of 1 row for connecting 7 rows of battery cells 1 in parallel. In order to connect the seven battery cells 1 in parallel and connect the seven battery cells 1 in adjacent rows in series, a second two-row second connecting the end electrodes 1A of the 14 battery cells 1 is connected. And a lead plate 5B.

  In the battery assembly of FIGS. 3 and 4, seven second lead plates 5B connecting the two rows of battery cells 1 are arranged in parallel to each other on the outer surface (the lower surface side in FIG. 3) of the second sub-holder 2b. ing. The seven second lead plates 5B each have seven battery cells 1 connected in parallel, and two adjacent rows of battery cells 1 connected in series. In addition, six second lead plates 5B for connecting the two rows of battery cells 1 are arranged in the middle on the outer surface (the upper surface side in FIG. 3) of the first sub-holder 2a, and at both ends on the output side. Two first lead plates 5A for connecting one row of battery cells 1 are arranged. The six second lead plates 5B arranged in the middle each connect seven stages of battery cells 1 in parallel and connect two adjacent rows of battery cells 1 in series. Two first lead plates 5A arranged at both ends connect seven stages of battery cells 1 in parallel. In the above battery assembly, 14 rows of battery cells 1 are connected in series in a zigzag manner while 7 stages of battery cells 1 are connected in parallel, and the first lead plate 5A connected at both ends is output as an output. It is connected to a terminal (not shown).

  As the lead plate 5, a metal plate having a small electric resistance and excellent heat conduction, for example, a nickel plate, a metal plate in which the surface of iron, iron alloy, copper, copper alloy or the like is plated with nickel or the like is used. The lead plate 5 is a metal plate having a thickness optimal for welding, for example, a metal plate having a thickness of 0.1 mm to 0.3 mm. A lead plate to be spot welded or laser welded is too thin or too thin to be welded to the end face electrode of the battery cell in an ideal state. For this reason, the lead plate is set to an optimum thickness in consideration of the flowing current and application.

Further, the lead plate 5 is provided with a connection piece 5 a for connecting to the circuit board 6 at one end thereof. As shown in FIGS. 3 and 4, the lead plate 5 is further bent at the distal end portion of the connection piece 5 a, and this distal end portion is directly electrically connected to the circuit board 6. The circuit board 6 has a slit 6a for inserting the tip of the connection piece 5a. The tip of the connection piece 5a is inserted into the slit 6a, and the connection piece 5a is soldered. Connected to. The circuit board 6 detects the intermediate potential of the battery assembly by inputting the voltage and current from the lead plate 5 through the connection piece 5a.
(Circuit board 6)

  The circuit board 6 is mounted with a protection circuit that protects the battery cell 1 by detecting the temperature, voltage, and the like of the battery cell 1. The circuit board 6 is fixed to the end surface of the second battery holder 2B, and connected to the connection pieces 5a of the lead plate 5 connected to the plurality of battery cells 1. The connection piece 5 a of the lead plate 5 is connected to a voltage detection circuit mounted on the circuit board 6. Thereby, the intermediate potential of the battery assembly can be detected on the circuit board 6 side. The circuit board 6 is a board on which a circuit necessary for driving the battery pack and its components, elements, and the like, such as a charge / discharge circuit and a protection circuit for controlling the charge / discharge current of the battery cells 1 in each row, are mounted on the glass epoxy Substrates can be used.

  Further, a heating element for heating the battery cell can be provided in contact with the surface of the battery cell. In this case, the circuit board is provided with a control circuit for turning on / off the energization of the heating element. The control circuit detects temperature and turns on / off the heating element. The control circuit includes a temperature sensor that detects the battery temperature or the outside air temperature. This temperature sensor is, for example, a thermistor. The thermistor detects the ambient temperature as a change in resistance value and inputs it to the control circuit. In this battery pack, a temperature sensor for detecting the temperature of the battery cell is provided close to the battery cell.

  The circuit board is provided only on one of the battery holders in addition to the structure provided on each battery holder, the circuit board is omitted on the other battery holder, and monitoring of two battery holders is shared by one circuit board. You can also

The first battery holder 2A and the second battery holder 2B have output lines connected by an output cable. The output of the entire battery pack is connected to the output terminal of the output connector provided on the first battery holder 2A. In this way, the battery holder 2 in which a large number of battery cells are connected in series and in parallel is connected in parallel to double the capacity.
(Connection board 55)

  On the other hand, a state detection line for monitoring the state of the battery cell 1 is connected between the first battery holder 2A and the second battery holder 2B. Thereby, the state of the battery cell 1 of the two battery holders 2 can be monitored by the protection circuit mounted on the circuit board 6 provided in one battery holder 2 as described above. Therefore, the battery pack includes a connection substrate 55 for connecting the first battery holder 2A and the second battery holder 2B. A state in which the first battery holder 2A and the second battery holder 2B are connected by the connecting substrate 55 is shown in the perspective view of FIG. The connection substrate 55 electrically connects battery holders that are electrically connected in parallel. Specifically, as shown in the circuit diagram of FIG. 6, between the first battery holder 2 </ b> A and the second battery holder 2 </ b> B, the parallel battery blocks having the same potential are electrically connected via the connection substrate 55. Yes. Here, extension tabs 5b are provided from the lead plates 5 of the first battery holder 2A and the second battery holder 2B, and the extension tabs 5b of the corresponding lead plates 5 are electrically connected to each other via the connecting substrate 55. ing. By connecting the lead plate directly to the connecting board in this way, it is possible to eliminate the trouble of wiring using a separate lead wire and to eliminate the risk of disconnection and to realize inexpensive and highly reliable wiring. . Also, by monitoring the battery cells of two battery holders with a single connection board, there is an advantage that the labor of providing a circuit board for each battery holder can be saved and the circuit board can be shared to reduce cost and space. .

The connection state of the battery holder 2 by such a connection board | substrate 55 is shown in FIGS. In these drawings, FIG. 7 is a schematic cross-sectional view showing a state in which the first battery holder 2A and the second battery holder 2B are connected to the connection board 55, and FIG. 8 is a first battery holder 2A connected to the connection board 55 of FIG. And the schematic sectional drawing which shows the state which connected the 2nd battery holder 2B is shown, respectively. As shown in these drawings, the first battery holder 2 </ b> A and the second battery holder 2 </ b> B are electrically connected via a connection substrate 55. The protection circuit mounted on the circuit board 6 monitors the cell voltage for each lead plate 5. Thereby, the cell voltage including the battery cell 1 accommodated in the first battery holder 2A can be monitored by one protective circuit. As a result, the protection circuit can be omitted in the first battery holder 2A. On the other hand, since the output connector is provided on the first battery holder 2A as described above, a necessary member for arranging the output connector can be mounted on the first battery holder 2A in place of the protection circuit. As described above, in the two divided holders, necessary circuits and the like can be dispersed and arranged efficiently, and space and cost can be reduced.
(Protection resistance 56)

  In the above example, the battery holders 2 are connected to each other by the connection substrate 55 as shown in FIG. Further, a protection resistor 56 is interposed between the battery holders 2. The protective resistance 56 is connected in series between the parallel battery blocks of the same potential between the battery holders 2. Thereby, it is possible to avoid a situation in which an excessive current flows into the battery cell due to a short circuit or the like. Specifically, in a configuration in which a large number of battery cells are connected in parallel, when any one of the battery cells is short-circuited, current concentrates on this battery cell having a low resistance, and current from other battery cells flows. Become. Moreover, when battery cells are connected in parallel, the greater the number of parallel cells, the lower the combined resistance of the internal resistances. For this reason, there is a possibility that a large current flows into one battery cell and generates heat. Therefore, a protective resistor 56 is provided between the parallel battery blocks connected in parallel.

  The protective resistor 56 is mounted on the connection board 55. In this example, a protective resistor 56 is provided for each parallel battery block, that is, for each battery module connected in series. As a result, when a large current is concentrated in some battery cells during a short circuit or the like, the current value can be suppressed and heat generation can be reduced. However, the protective resistor 56 need not be provided in all the parallel battery blocks, and can be received even at a predetermined interval. In this example, as shown in the circuit diagram of FIG. 6, it is provided every other parallel battery block, that is, every time two battery modules are connected in series.

  The resistance value of the protective resistor 56 is preferably set to a value comparable to the internal resistance of the battery cell, for example, 20 mmΩ to 30 mmΩ. If set in this way, the amount of heat generated as a resistance value comparable to that of a normal battery cell can be dealt with by the same measure as the amount of heat generated during general charge / discharge. That is, by connecting a plurality of battery cells in parallel, the combined resistance of the internal resistances decreases, so that a larger amount of current easily flows and the amount of heat generation increases. For this reason, by providing the protective resistance 56 in series with respect to the battery cells connected in parallel, that is, between the divided battery holders constituting the battery cells connected in parallel, the combined resistance value Can be secured at least the internal resistance of one battery cell. As a result, heat countermeasures can be taken in the same way as heat countermeasures when heat is generated due to a high charge / discharge current flowing through the battery cells, and the situation of considering the addition of a special heat dissipation structure can be avoided.

  In the example of FIGS. 7 and 8 described above, the configuration in which the first battery holder 2A and the second battery holder 2B in which the battery holder is divided is overlapped is described. However, the configuration is not limited to this example. For example, FIG. As shown, it goes without saying that the first battery holder 2A and the second battery holder 2B may be arranged apart from each other. With such an arrangement, a space is provided between the battery holders, and the heat generated in each battery holder is exhausted into this space to improve heat dissipation, and the heat generated in one battery holder is easily transferred to the other battery holder. Safety can be improved by avoiding heating.

  The connection between the connection substrate 55 and the first battery holder 2A and the second battery holder 2B is performed by screwing. At this time, as shown in FIGS. 4 and 10, a fitting groove 62 is provided on the joint surface obtained by dividing the battery holder 2 </ b> A into the first sub-holder 2 a and the second sub-holder 2 b, and a flange nut 60 is provided in the fitting groove 62. It is pinched and fixed. The flange nut 60 can be prevented from falling out of the fitting groove 62 by the flange. By doing in this way, the nut fixing structure using the joint surface of the first sub-holder 2a and the second sub-holder 2b can be realized at low cost without employing an expensive insert nut structure or the like. Further, at the time of screw fastening, the extension tab 5 b extended from the lead plate 5 of the battery holder 2 and the connecting substrate 55 are pressed together. Thereby, the connection board 55 can be mechanically connected to the battery holder 2 and also can be electrically connected.

  The battery pack according to the present invention can be suitably used as a battery pack for driving an electric motorcycle, an electric wheelchair, an electric tricycle, an assist bicycle, an electric cart, or the like.

DESCRIPTION OF SYMBOLS 100 ... Battery pack 1 ... Battery cell; 1A ... End surface electrode 2 ... Battery holder; 2A ... First battery holder; 2B ... Second battery holder; 2a ... First sub holder; 2b ... Second sub holder 4 ... Outer case 5 ... Lead Plate 5A ... 1st lead plate 5B ... 2nd lead plate 5a ... Connection piece 5b ... Extension tab 6 ... Circuit board; 6a ... Slit 32 ... Projection prevention part (projection)
34 ... Battery storage space 55 ... Connection board 56 ... Protection resistance 60 ... Flange nut 62 ... Fitting groove

Claims (5)

A plurality of battery cells (1),
A battery holder (2) for housing the plurality of battery cells (1);
A plurality of lead plates (5) attached to the battery holder for connecting the plurality of battery cells (1) in parallel,
A battery pack comprising:
The battery holder is divided into a first battery holder (2A) and a second battery holder (2B),
Of the lead plate (5) attached to the first battery holder (2A) and the lead plate (5) attached to the second battery holder (2B), lead plates (5) having the same potential are A battery pack connected through a protective resistor (56). The battery pack according to claim 1, further comprising:
The first battery holder (2A) and the second battery holder (2B) comprises a connection substrate (55) for electrically connecting,
The battery pack, wherein the protective resistor (56) is mounted on the connection board (55). The battery pack according to claim 1 or 2,
The battery pack, wherein the protective resistor (56) is provided every other battery cell (1) connected in parallel with respect to adjacent parallel battery blocks. The battery pack according to any one of claims 1 to 3, further comprising:
A circuit board (6) mounted with a protection circuit for monitoring the voltage of the battery cell (1) housed in the first battery holder (2A) and the second battery holder (2B) is provided. Battery pack. The battery pack according to any one of claims 1 to 4, further comprising:
The battery pack, wherein the protective resistance (56) is substantially equal to the internal resistance of the battery cell (1).

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