JPH0360336A - Battery load connecting device - Google Patents

Abstract

PURPOSE:To cancel the imbalance of a discharge quantity by providing an intermediate terminal at the center of a plurality of batteries connected in series for the batteries mounded on a vehicle, and by using lower-tension loads to be alternately connected to the one side and the other side of said batteries. CONSTITUTION:A plurality of batteries 1 are connected in series, and to both their terminals 4, 4, a higher tension load 2 is connected, and to an intermediate terminal 5 and the terminal 4, a lower tension load 3 is connected by change- over switches 6, 7. To a section A between the terminal 4 and the intermediate terminal 5, the current of I1+I2 flows, and to a section B between the other side terminal 4 and the intermediate terminal 5, the current of I1 flows. Accordingly, a difference is generated between the discharge quantities of the batteries of the section A and the section B. When the difference of the discharge quantities comes to a limit or larger, then the change-over switches 6, 7 are change over, and the discharge quantity of the battery of the section A is reduced, and the discharge quantity of the battery of the section B is increased, and the imbalance of the discharge quantities is cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for connecting a load to a battery in a battery-powered forklift or the like.

[Conventional technology]

A battery-powered forklift uses an onboard battery to supply power to an electric motor for driving a hydraulic pump, an electric motor for driving, and relatively low-power electrical equipment such as headlights, horns, and electric attachments.

For example, as shown in FIG. 5, an electric motor 2 and an electric device 3 are connected to a battery 1.

On the other hand, the higher the voltage input to the electric motor, the more efficient it is during operation.
For example, it is set to 96V.

However, if the battery voltage is high, in the case shown in FIG. 5, the high voltage will flow to the electrical equipment 2 with relatively low power, making it unusable or deteriorating its durability.

Note that high voltage electrical equipment may be used, but high voltage electrical equipment is not very commercially available and is difficult to obtain.

Therefore, conventionally, as shown in Fig. 6, a plurality of batteries are connected in series, and an electric motor 2 is connected to both terminals 4, 4 so that a high voltage E flows, and one terminal 4 and an intermediate terminal 5 are connected to the electric motor 2. The device 3 is connected to allow low voltage to flow, so that the low voltage electrical device 3 can be used.

[Problem to be solved by the invention]

However, when connected as described above, a current of 11 flows through part A between one terminal 4 and the intermediate terminal 5.
Regarding the part B between the other one terminal 4 and the intermediate terminal 5, I
, +1. A current flows, and the battery discharge amount becomes unbalanced between the battery in the A section and the battery 2 in the B section.

In this way, if the amount of battery discharged is unbalanced, it cannot be resolved by normal charging, and the life of the battery itself will be shortened if used for a long period of time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a battery load connection device that can solve the above-mentioned problems.

[Means and effects for solving the problem] First and second changeover switches are provided to control the connection between the intermediate terminal, the low voltage load, and the terminal, and the battery and the battery on one side of the intermediate terminal are connected to the low voltage load. This allows power to flow alternately from the battery on the other side.

〔Example〕

As shown in FIG. 1, a plurality of batteries 1 are connected in series,
The electric motor 2, that is, a high voltage load is connected to both terminals 4.4, and the intermediate terminal 5 is connected to the first/second selector switch 6.4.
At 7, the connection between the terminals 4 and the electrical equipment 3, that is, a low voltage load is controlled.

Therefore, if the electrical equipment 3 and one terminal 4 are connected with the first changeover switch 6 and the electrical equipment 3 and the intermediate terminal 5 are connected with the second changeover switch 7 as shown in FIG.
There are 1. A current of +12 flows, and a current of 1
1 current flows.

In addition, as shown in FIG. 2, the electric equipment 3 can be
If the intermediate terminal 5 is connected to the intermediate terminal 5, and the electrical device 3 is connected to the other terminal 4 using the second changeover switch 7, a current of 11 will flow to the battery 1 in the section A, and a current of I, +12 will flow to the battery 1 in the section B. current flows.

Therefore, electric power is supplied to the electric motor 2 and the electrical equipment 3 with the first and second changeover switches 6.7 in the state shown in FIG. At this time, the discharge amount of the battery in section A is large and the discharge amount of the battery in section B is small, so that a difference occurs between the discharge amounts of the batteries in section A and B. If the difference in the discharge amount of the batteries mentioned above exceeds the limit, the first
By switching the second changeover switch 6.7, the amount of discharge of the battery in section A is reduced and the amount of discharge of the battery in section B is increased, thereby eliminating the imbalance between the amount of discharge of the batteries in section A and section B.

In the above embodiment, the first and second changeover switches 6°7 are manually changed over, but as shown in FIG. The switching means 10 may automatically switch the first and second changeover switches 6.7 between the state shown in FIG. 1 and the second state alternately.

FIG. 4 shows a third embodiment, in which a first discharge meter 12 is placed on one terminal 4 side to detect the discharge amount of the battery in section A, and a discharge meter 12 is placed on the other terminal 4 side to detect the discharge amount of the battery in section B. 2 discharge meter 1
3, the first and second changeover switches 6.7 are electromagnetic switches, and the contactor coil 14 is connected to a controller 15.
energization control so that the first and second changeover switches 6 and 7 can be automatically switched, and the detected values of the first and second discharge meters 12 and 13 are manually input to the controller 15,
The amount of discharge of the battery in section A and the amount of discharge of the battery in section B are calculated, and when the difference in the amount of discharge reaches a predetermined value, the contact coil 14 is energized.

Therefore, when each battery 1 is fully charged, the indications of the first and second discharge meters 12.13 are reset to zero, and when the electrical equipment 3 is energized, the amount of discharge of the battery in section A and the amount of discharge of the battery in section B are reset. There is a difference in the discharge amount, and the difference in the discharge amount is the first,
The controller 15 calculates the amount of discharge detected by the second discharge meter 12.13, and when the difference in the amount of discharge exceeds the limit, the contactor coil 14 is energized and the first/second changeover switch 6.7 is turned on. By switching, the discharge amount of the battery in the B section is made larger than the discharge amount of the battery in the A section, thereby eliminating the imbalance in the amount of emitted ts.

〔Effect of the invention〕

(1) All battery voltages can be passed through high-voltage loads, and H battery voltage can be passed through low-voltage loads, improving the durability of low-voltage loads. can.

In addition, by switching the first and second selector switches 6.7, the discharge amount of the battery with a high discharge amount can be reduced, and the discharge amount of a battery with a low discharge amount can be increased, thereby eliminating the imbalance in the discharge amount. Therefore, the battery life can be extended.

(2) The first/second selector switch 6 is automatically switched at regular intervals.
．． 7 can be switched, and reliability is improved because there is no need to forget to switch.

(3> Since the first and second selector switches 6.7 are switched based on the difference in the f1! amount, the imbalance in the f1! amount can be resolved with high accuracy.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams showing the first embodiment of the present invention, Figures 3 and 4 are circuit diagrams showing the second and third embodiments, and Figures 5 and 6 are different from each other. FIG. 2 is a circuit diagram of a conventional example. 1 is a battery, 2 is an electric motor, 3 is an electric device, 4 is a terminal, 5 is an intermediate terminal, and 6 and 7 are first and second changeover switches. Figure Figure Figure

Claims (3)

[Claims] (1) Multiple batteries 1 are connected in series, and both terminals 4,
4, a high voltage load is connected to the plurality of batteries 1, and an intermediate terminal 5 is provided in the center of the plurality of batteries 1, and a first changeover switch 6 connects and controls the connection between the intermediate terminal 5, one terminal 4 and the low voltage load. A battery load connection device characterized in that a second changeover switch 7 is provided for controlling the connection between the intermediate terminal 5, the other terminal 4, and a low voltage load. (2) The battery load connection device according to claim 1, further comprising a switching means for automatically switching the first and second changeover switches 6 and 7 at predetermined time intervals. (3) A first discharge meter 12 that detects the discharge amount of the battery 1 on one terminal 4 side from the intermediate terminal 5, and a second discharge meter that detects the discharge amount of the battery 1 on the other terminal 4 side from the intermediate terminal 5. 13, and a switching means for switching the first and second changeover switches 6 and 7 based on the difference in the amount of discharge detected by the first and second discharge meters 12 and 13. Load connection device.