JP3676225B2 - Battery pack for electric vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a battery pack for an electric vehicle that is mounted on an electric vehicle such as an assist bicycle and supplies electric power to a driving motor.
[0002]
[Prior art]
The assist bicycle is built in so that the battery pack can be attached to and detached from a vertical frame having a saddle fixed to the upper end. The assist bicycle having the battery pack built therein can run stably because the heavy battery pack is disposed near the center of gravity. The battery pack housed here is manufactured to have an elongated outer shape so that it can be incorporated in the frame. In this battery pack, a battery core connecting a plurality of batteries in an elongated shape is housed in a case. The battery core is connected to the discharge connector and the charge connector with lead wires, and these connectors are fixed to the upper and lower ends of the case. A discharge plug is inserted into the discharge connector, and a charge plug is inserted into the charge connector. The discharge plug is connected to the motor and supplies power to the motor. The charging plug is connected to the charger when charging the battery pack. Furthermore, the battery pack of the assist bicycle includes a display unit that calculates and displays the remaining amount of the battery. The battery pack is charged while attached to the bicycle, or removed from the bicycle and charged.
[0003]
[Problems to be solved by the invention]
In the battery pack for assist bicycles with the above structure, the discharge connector and the charge connector are fixed apart from the top and bottom of the case, so the structure for firmly fixing the two connectors to the determined position of the case is complicated. Therefore, it takes time to assemble, and the manufacturing cost increases. Moreover, the lead wire for connecting the discharge connector and the charge connector to the battery core becomes long, and there is a disadvantage that the power loss due to the voltage drop by the lead wire is also increased.
[0004]
In addition to the two connectors, the battery pack incorporates a printed circuit board on which an electronic circuit is mounted in order to control charging / discharging of the battery or to detect the remaining amount of the battery. The printed circuit board is disposed below the battery core so as not to be heated by the heat of the battery core. The printed circuit board disposed in the lower part of the case needs to be protected from the impact of a heavy battery core. In particular, since bicycles travel on uneven roads, battery packs are frequently subjected to strong impacts. The upper and lower impacts of the battery pack cause the heavy battery core to swing up and down and damage the printed circuit board disposed below the heavy battery core. For this reason, in order to protect a printed circuit board from a heavy battery core, the battery pack for this application requires a more complicated load-bearing structure, which increases the manufacturing cost.
[0005]
Furthermore, since the assist bicycle requires a large-capacity battery, a large-torque motor, and a control circuit with a large current capacity for controlling a large current of the motor, the cost of these parts becomes extremely high. In addition, the bicycle frame is required to have a unique structure and strong strength in order to incorporate a heavy battery pack, and the manufacturing cost of the frame also increases. However, assist bicycles are not motorcycles equipped with engines, so they cannot be sold if the selling cost is higher than motorcycles. For this reason, the selling cost is limited, and it is extremely important how the cost of the parts to be used can be reduced.
[0006]
If the battery pack has a tough structure and is resistant to impact, the manufacturing cost will be high. The present invention has been developed for the purpose of providing a battery pack for an electric vehicle that can be mass-produced inexpensively while simplifying the overall structure and making it a tough structure.
[0007]
[Means for Solving the Problems]
The battery pack for an electric vehicle of the present invention includes a battery core 2 in which a plurality of batteries are connected in an elongated shape, a case 1 housing the battery core 2, and a case 1 provided in the case 1 to the outside. A discharge connector 5 for supplying power, a charging connector 6 for charging a battery provided in the case 1 and a battery built in the case 1 and an electronic circuit for controlling charging / discharging of the battery are mounted. And a substrate 7. Further, in the battery pack, the discharge connector 5, the charge connector 6, and the printed board 7 are fixed to the inner case 4 that is a plastic molded body to form a charge / discharge block 3 having an integral structure. The battery pack incorporates the charge / discharge block 3 in the lower part of the case 1 and exposes the discharge connector 5 and the charge connector 6 to the outside of the case 1.
[0008]
In the battery pack of the present invention, a load receiving plate 10 that supports the load of the battery core 2 is preferably disposed between the battery core 2 and the charge / discharge block 3. In this battery pack, the load receiving plate 10 is connected to the case 1, and the charge / discharge block 3 can be disposed below the load receiving plate 10.
[0009]
Furthermore, the battery pack of the present invention can be mounted on the printed circuit board 7 of the charge / discharge block 3 with a remaining amount calculation circuit that calculates the remaining amount of the battery. A shunt resistor for detecting battery current can be fixed to the printed circuit board 7.
[0010]
Furthermore, in the battery pack of the present invention, the printed circuit board 7 can be equipped with a fuse 21 that is blown when an overcurrent flows through the battery. In this battery pack, the inner case 4 of the charge / discharge block 3 is provided with a holding portion 22 that holds the fuse 21, and the fuse terminal that directly connects the fuse 21 to the printed circuit board 7 can be fixed.
[0011]
Furthermore, in the battery pack of the present invention, the metal terminal 12 of the discharge connector 5 can be directly fixed to the inner case 4 of the charge / discharge block 3, and the metal terminal 12 can be directly fixed to the printed circuit board 7. Furthermore, in the battery pack of the present invention, the metal terminal 13 of the charging connector 6 can be directly fixed to the inner case 4 of the charging / discharging block 3, and the metal terminal 13 can be directly fixed to the printed circuit board 7. .
[0012]
Furthermore, the battery pack for an electric vehicle of the present invention can be attached to an assist bicycle.
[0013]
DETAILED DESCRIPTION OF THE 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 an electric vehicle for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows.
[0014]
Further, in this specification, in order to facilitate understanding of the scope of claims, the numbers corresponding to the members shown in the examples are referred to as “the scope of claims” and “the means for solving the problems”. It is added to the member shown by. However, the members shown in the claims are not limited to the members in the embodiments.
[0015]
The battery pack of the present invention is mounted on an electric vehicle and supplies power to a driving motor. In this specification, an electric vehicle means a vehicle driven by electric power of a battery pack to be mounted. Therefore, the battery pack of the present invention can be used for all vehicles that are electrically driven with the battery pack mounted, such as an assist bicycle, an electric motorcycle, an electric wheelchair, an electric tricycle, and an electric cart. Hereinafter, an embodiment in which the electric vehicle is an assist bicycle will be described in detail.
[0016]
The battery pack shown in the front view of FIG. 1, the rear view of FIG. 2, and the cross-sectional view of FIG. 3 houses a battery core 2 in which a plurality of batteries are connected in an elongated shape, and the battery core 2 is accommodated. A case 1, a discharge connector 5 provided in the case 1 for supplying electric power to the outside, a charging connector 6 provided in the case 1 for charging a built-in battery, and a built-in case 1, And a printed circuit board 7 on which an electronic circuit for controlling charge / discharge or detecting the remaining amount of the battery is mounted.
[0017]
The discharge connector 5, the charge connector 6, and the printed circuit board 7 are fixed to an inner case 4 that is a plastic molded body to form a charge / discharge block 3 having an integral structure. The charge / discharge block 3 is built in the lower part of the case 1 and exposes the discharge connector 5 and the charge connector 6 to the outside of the case 1.
[0018]
The battery core 2 is connected in a slender shape by connecting secondary batteries, which are cylindrical batteries or square batteries, in series or in parallel. The secondary battery is a rechargeable battery such as a nickel-hydrogen battery, a nickel-cadmium battery, or a lithium ion secondary battery. The battery core 2 is connected in an elongated shape, for example, by arranging cylindrical batteries in two rows, so that the batteries in one row are located in the valleys of the batteries in the other row, that is, piles are stacked. The battery cores 2 are connected by lead wires, and the surfaces are further covered with a heat shrink film or the like to be connected to an integral structure.
[0019]
The case 1 includes a first case 1A and a second case 1B that are molded of plastic, and the first case 1A and the second case 1B are connected by screws 19. 1st case 1A and 2nd case 1B are shape | molded in the shape which can accommodate the battery core 2 in the upper part, and the charging / discharging block 3 in the lower part. Further, the case 1 accommodates the charge / discharge block 3 and opens connector windows 1a and 1b for exposing the charge connector 6 and the discharge connector 5 of the charge / discharge block 3 to the outside. In the case 1 in the figure, the connector window 1b of the discharge connector 5 is opened at the corners of the bottom surface and the bottom side surface, and the connector window 1a of the charging connector 6 is opened at the bottom side surface. In this structure, since the weight of the battery pack acts in a direction in which the discharge connector 5 is pressed against the discharge terminal of the bicycle, the discharge terminal 5 can be reliably inserted into and electrically connected to the discharge connector 5.
[0020]
The connector window 1a for exposing the charging connector 6 to the outside is closed by an open / close lid 8 that is elastically closed. This battery pack can reduce the contact failure of the charging connector 6. The connector window 1b that exposes the discharge connector 5 to the outside is not closed with an opening / closing lid. This is because the discharge connector 5 is always connected to the discharge terminal of the bicycle while the battery pack is attached to the bicycle. The charging connector 6 does not always connect a charging plug. Connect the charging plug only when charging the battery pack. The connector window 1a with the open / close lid 8 prevents foreign matter from adhering to the charging connector 6 in a state where the charging plug is not connected, thereby reducing contact failure.
[0021]
Furthermore, in the case 1 shown in the figure, a handle 9 is integrally formed at the upper end so that the battery pack removed from the bicycle can be easily held and also can be easily attached to and detached from the bicycle. Furthermore, the case 1 has a load receiving plate 10 that supports the load of the battery core 2 between the battery core 2 and the charge / discharge block 3. The load receiving plate 10 has a structure in which both side edges are connected to a locking portion 11 provided on the case 1 and is not pushed downward by the battery core 2. The case 1 shown in the figure is provided with a protruding portion 11 </ b> A protruding on the inner surface to serve as a locking portion 11, and further provided with a bent portion 11 </ b> B protruding inside the case 1 as a locking portion 11. The case 1 provided with the load receiving plate 10 can effectively prevent the charge / discharge block 3 from being damaged by the load of the battery core 2.
[0022]
The inner case 4 of the charge / discharge block 3 directly fixes the metal terminal 12 of the discharge connector 5. The metal terminal 12 is directly soldered and fixed to the printed circuit board 7. The metal terminal 12 of the discharge connector 5 is inserted into the metal terminal of the discharge plug fixed to the bicycle. Therefore, as shown in the enlarged view of FIG. 4, the metal terminal 12 of the discharge connector 5 is formed by folding back a metal plate that can be elastically deformed and bending both ends thereof further inwardly, so that the inserted metal terminal 20 is elastic. The shape can be sandwiched between the two.
[0023]
In the inner case 4, the metal terminal 13 of the charging connector 6 is also directly fixed, and the metal terminal 13 is also directly fixed to the printed circuit board 7 by soldering. The inner case 4 is provided with a connecting recess that can be connected by inserting a charging plug, and the metal terminal 13 of the charging connector 6 is fixed inside the connecting recess.
[0024]
The printed circuit board 7 is mounted with a remaining amount calculation circuit (not shown) for calculating the remaining amount of the battery. The remaining amount calculation circuit calculates the remaining amount of the battery by accumulating the charge / discharge current of the battery, and displays the remaining amount. The remaining amount calculation circuit in the figure displays the remaining amount by the number of lighting of the plurality of light emitting diodes 15 and increases the number of light emitting diodes 15 to be lit as the remaining amount increases. The light emitting diode 15 is fixed to the display unit 14 that is integrally formed with the inner case 4. In order that the light emitting diode 15 of the display unit 14 can be seen from the outside of the case 1, a display window 1c that exposes the display unit 14 to the outside is opened in the case 1, and the display unit 14 is provided in the display window 1c. ing.
[0025]
In order for the remaining amount calculation circuit to detect the charging / discharging current of the battery, the printed circuit board 7 is connected in series with the battery, and a shunt resistor (not shown) for detecting the current is fixed. The voltage at both ends of the shunt resistor is amplified by an amplifier, and the charge / discharge current of the battery is detected.
[0026]
Furthermore, as shown in FIG. 5, the printed circuit board 7 is equipped with a fuse 21 that is blown when an overcurrent flows through the battery. The fuse 21 is connected in series with the battery. When an excessive current flows through the battery, the fuse 21 is blown to interrupt the current. The fuse 21 is mounted on the printed circuit board so that it can be replaced. Therefore, a fuse terminal for connecting the fuse 21 is fixed to the printed circuit board. The fuse terminal is a metal plate that can be elastically deformed, and the terminals of the fuse 21 are elastically sandwiched and connected. In order to hold the fuse 21 in a fixed position, the inner case 4 is provided with a holding portion 22 for fitting and holding the fuse 21.
[0027]
Furthermore, the printed circuit board 7 is also provided with a protection circuit for preventing overcharge and overdischarge of the battery. The protection circuit prevents overcharging by cutting off the charging current when the battery is fully charged. Further, when the battery is discharged and the remaining amount reaches a predetermined capacity, the discharge current is cut off to prevent overdischarge.
[0028]
The inner case 4 is integrally formed of plastic as a whole, and a peripheral wall 16 protrudes around the upper surface, and a printed circuit board 7 is disposed inside the peripheral wall 16. In the inner case 4, the opening of the peripheral wall 16 is closed with a waterproof cover 17. As shown in FIG. 3, the waterproof cover 17 has ridges 18 that are wrapped outside the peripheral wall 16. The peripheral wall 16 is fitted inside the ridge 18 and the waterproof cover 17 is connected to the peripheral wall 16. This structure can prevent water entering the inside of the case 1 from entering the charge / discharge block 3.
[0029]
The waterproof cover 17 may be integrated with the load receiving plate 10 as shown in FIG. The load receiving plate 10 in this figure is provided with a ridge 18 projecting on the lower surface by integrally molding. The peripheral wall 16 of the inner case 4 is put inside the ridge 18, and the load receiving plate 10 closes the upper surface opening of the peripheral wall 16 with a waterproof structure. This structure can prevent water from entering the inner case 4 while protecting the inner case 4 with the load receiving plate 10.
[0030]
The inner case 4 is fitted in the lower part of the case 1 and stored in a fixed position. The inner case 4 can also be provided with convex portions that are inserted into the connector windows 1a, 1b and the display window 1c, and the convex portions can be inserted into the connector windows 1a, 1b and the display window 1c to be disposed at fixed positions. . Further, it can be bonded to the inner surface of the case 1 or fixed by screwing.
[0031]
【The invention's effect】
The battery pack for an electric vehicle of the present invention has a feature that it can be mass-produced at low cost while having a strong structure resistant to impact. That is, the battery pack of the present invention has a discharge connector, a charge connector and a printed circuit board fixed to an inner case of a plastic molded body to form a charge / discharge block of an integrated structure, and this charge / discharge block is built in the lower part of the case, This is because the discharge connector and the charge connector are exposed to the outside of the case. Since the battery pack having this structure is provided with both the charging connector and the discharging connector in the charging / discharging block, the charging / discharging block can be easily assembled by placing it in the case. In addition, since it is not necessary to separately wire both the charging connector and the discharging connector, it can be easily wired. Furthermore, since it is housed in the case in a state where it is completed as a charge / discharge block, not only the strength of the case but also the printed circuit board and the like are protected by the inner case of the charge / discharge block, so that a strong structure can be achieved.
[0032]
Further, according to the present invention, since the printed circuit board, the charging connector, and the discharging connector are formed as an integrated charging / discharging block, a load is applied between the battery core and the charging / discharging block as in the battery pack described in claim 2. By arranging the backing plate, the charge / discharge block can be protected in an ideal state by the load backing plate. This structure has an advantage that it can extremely effectively prevent a defect that a heavy battery core vibrates and damages a printed circuit board, a charging connector, a discharging connector and the like.
[0033]
Further, since the battery pack according to claim 3 of the present invention has the remaining amount calculation circuit mounted on the printed circuit board of the charge / discharge block, the remaining amount of the battery can be displayed and used conveniently.
Furthermore, since the battery pack according to claim 5 of the present invention is provided with a fuse that is blown when an overcurrent flows through the battery, the battery pack can be used while protecting the battery from the overcurrent. Furthermore, in the battery pack according to claim 6 of the present invention, the inner case is provided with a holding portion for holding the fuse, and the fuse terminal for directly connecting the fuse to the printed circuit board is fixed. Has the feature that can be held firmly in place.
[0035]
Furthermore, the battery pack according to claims 7 and 8 of the present invention is such that the metal terminal of the discharge connector or the metal terminal of the charge connector is directly fixed to the inner case, and these metal terminals are directly connected to the printed circuit board. Since it is fixed to the connector, the discharge connector and the charging connector are securely fixed, and the loss due to the voltage drop due to the large current can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view of a battery pack for an electric vehicle according to an embodiment of the present invention. FIG. 2 is a rear view of the battery pack for an electric vehicle shown in FIG. FIG. 4 is an enlarged cross-sectional view showing metal terminals of the discharge connector. FIG. 5 is a bottom view of the inner case of the battery pack shown in FIG. 3. FIG. Sectional view of vehicle battery pack [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Case 1A ... 1st case 1B ... 2nd case 1a ... Connector window 1b ... Connector window 1c ... Display window 2 ... Battery core 3 ... Charging / discharging block 4 ... Inner case 5 ... Discharge connector 6 ... Charging connector 7 ... Printed circuit board DESCRIPTION OF SYMBOLS 8 ... Opening / closing lid 9 ... Handle 10 ... Load receiving plate 11 ... Locking part 11A ... Projection 11B ... Bending part 12 ... Metal terminal 13 ... Metal terminal 14 ... Display part 15 ... Light emitting diode 16 ... Perimeter wall 17 ... Waterproof cover 18 ... ridge 19 ... screw 20 ... metal terminal 21 to be inserted ... fuse 22 ... holding part

Claims (9)

A battery core (2) in which a plurality of batteries are connected in an elongated shape, a case (1) containing the battery core (2), and the case (1) provided to supply power to the outside Discharge connector (5), charge connector (6) for charging the battery built in the case (1), and electronic circuit built in the case (1) to control the charge / discharge of the battery A battery pack for an electric vehicle comprising a printed circuit board (7),
The discharge connector (5), the charge connector (6), and the printed circuit board (7) are fixed to the inner case (4), which is a plastic molded body, to form an integrated charge / discharge block (3). A battery pack for an electric vehicle characterized in that 3) is built in the lower part of the case (1) and the discharge connector (5) and the charging connector (6) are exposed to the outside of the case (1). Between the battery core (2) and the charge / discharge block (3), a load receiving plate (10) that supports the load of the battery core (2) is disposed, and the load receiving plate (10) is attached to the case (1 The battery pack for an electric vehicle according to claim 1, wherein a charge / discharge block (3) is disposed below the load receiving plate (10). The battery pack for an electric vehicle according to claim 1, wherein a remaining amount calculation circuit for calculating a remaining amount of the battery is mounted on the printed circuit board (7) of the charge / discharge block (3). The battery pack for an electric vehicle according to claim 3, wherein a shunt resistor for detecting a battery current is fixed to the printed circuit board (7). The battery pack for an electric vehicle according to claim 1, wherein a fuse which is blown when an overcurrent flows through the battery is mounted on the printed circuit board (7). The inner case (4) of the charge / discharge block (3) is provided with a holding part (22) that holds the fuse (21), and the fuse terminal that directly connects the fuse (21) to the printed circuit board (7) is fixed. A battery pack for an electric vehicle according to claim 5. The metal terminal (12) of the discharge connector (5) is directly fixed to the inner case (4) of the charge / discharge block (3), and this metal terminal (12) is directly fixed to the printed circuit board (7). The battery pack for an electric vehicle according to claim 1. The metal terminal (13) of the charging connector (6) is directly fixed to the inner case (4) of the charge / discharge block (3), and this metal terminal (13) is directly fixed to the printed circuit board (7). The battery pack for an electric vehicle according to claim 1. The battery pack for an electric vehicle according to claim 1, wherein the electric vehicle is an assist bicycle.

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