JP2003173822A - Charge and discharge system and how to use it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge and discharge system with a simple configuration in which a plurality of secondary cells constituting a cell pack are connected in parallel at charging, while they are connected in series only or in combination of series and parallel at discharging when used with an equipment. <P>SOLUTION: In case of charging, a cell pack composed of a plurality of secondary cells is combined with a charger and the secondary cells are connected in parallel and when the equipment is used, the cell pack is combined with the used equipment and the secondary cells are discharged by connecting them only in series or in a combination of series and parallel. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging / discharging system in which a battery pack composed of a plurality of secondary batteries is combined with a charger when charging and combined with the device when using the device.

[0002]

2. Description of the Related Art A plurality of reusable secondary batteries can be used in combination to increase the power output and capacity of a power source, and are commonly used in AV equipment and personal computers.

However, in the case where a plurality of batteries are connected in series, if the battery capacity and the battery characteristics are different, the depths of charge and discharge of the respective batteries are different, and the discharge performance typified by cycle characteristics is significantly reduced. Sometimes. It also causes a decrease in the reliability and safety of the battery.

In order to avoid these, it is effective to individually control the voltage, temperature, output, etc. of the constituent batteries. In other words, when charging the battery pack, parallel connection,
When discharging (using), discharging is performed only in series or in a combination of series and parallel, so that stable charging and discharging can be performed even if a difference in battery capacity or battery characteristics occurs. In order to materialize this, a circuit using a switch for the purpose of changing the circuit at the time of charging and at the time of discharging has been proposed (Japanese Patent Laid-Open No. 2000-197273,
JP 2001-186668 A).

[0005]

[Problems to be Solved by the Invention] However, in the past,
In a configuration in which a switch is used to change the circuit at the time of charging / discharging, a protection circuit or the like considering a failure of the switch is required. Furthermore, there is a problem in that the wiring is lengthened due to the provision of the switch and the work efficiency is impaired.

The present invention has been made in view of the above problems, and discharges battery packs composed of a plurality of secondary batteries in parallel when charging, only in series connection when using equipment, or in combination connection of series and parallel. It is an object of the present invention to provide a charging / discharging system having a simple structure.

[0007]

In order to solve the above problems, according to the present invention, a battery pack composed of a plurality of secondary batteries, a charger for charging the battery pack, and the battery pack as a power source are used. In a charging / discharging system that is used in combination with devices to be used, switching of circuits at the time of charging / discharging is changed by each combination. That is, when using the charge / discharge system described above, when charging, the battery pack and the charger are combined to charge the secondary battery in parallel connection, and when the device is used, the battery pack and the device are combined. It is characterized in that the secondary battery is discharged only in series connection or in combination connection of series and parallel.

As a result, the charging / discharging circuit can be switched with a simple structure without using a switch or the like.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention uses a battery pack composed of a plurality of secondary batteries, a charger for charging the battery pack, and the battery pack as a power source. In a charging / discharging system used in combination with a device, the battery pack is provided with positive and negative terminals of the secondary battery independently, and the charger has a positive and negative terminal corresponding to the positive and negative terminals of the battery pack. Is provided,
Further, the positive terminal and the negative terminal are connected in parallel inside the charger, the device is provided with positive and negative terminals corresponding to the positive and negative terminals of the battery pack, and the positive terminal and the negative terminal inside the device. Is connected only in series or in a combination of series and parallel.

In this structure, the battery pack, the charger and the equipment are provided with terminals corresponding to the number of batteries constituting the battery. Furthermore, the individual batteries that make up the battery pack are not connected inside the pack, and the inside of the charger is wired so that the terminals are connected in parallel. Alternatively, they are wired so as to be a combination connection of series and parallel. Therefore, since there is no switch for changing the circuit, wiring for this purpose and a protection circuit against switch failure are not required. Further, since the circuit is simple and the wiring is simplified, it is possible to prevent the work efficiency from being lowered due to the wiring.

The invention according to claim 2 of the present invention is characterized in that, in the charging / discharging system according to claim 1, the secondary battery is a lithium ion secondary battery, which is vulnerable to overcharge. The lithium ion secondary batteries can be collectively controlled.

According to a third aspect of the present invention, in the charging / discharging system according to the first aspect, the battery pack has a built-in device for detecting and outputting a battery temperature. Yes, the battery temperature can be controlled.

As a device for detecting and outputting the battery temperature, a conventionally known device such as a combination of a thermocouple and a display device or an irreversible thermolabel having a simple structure can be used.

According to a fourth aspect of the present invention, when the charge / discharge system according to the first aspect is used, at the time of charging, the battery pack and the charger are combined to connect the secondary batteries in parallel. The charging / discharging system is used by discharging the secondary battery only in series connection or in combination of series and parallel when the device is used. Is.

The present embodiment will be described below with reference to the drawings.

1 to 3 show the battery pack, the charger, and the wiring inside the device of the present invention in an easy-to-understand manner, and show the method of use during charging and during use of the device.

FIG. 1 shows the wiring inside the battery pack 1. The plurality of batteries 2 are not connected inside the battery pack 1, and each battery 2 is provided with a positive terminal 3 and a negative terminal 4 outside the battery pack 1.

FIG. 2 shows the wiring inside the charger 5 and the method of use during charging. Inside the charger 5, FIG.
The positive terminals 3'corresponding to the positive terminal 3 and the negative terminal 4 of the battery pack 1 shown in FIG.

Therefore, by mechanically fitting the battery pack 1 and the charger 5, the batteries 2 in the battery pack 1 can be charged individually and in parallel.

FIG. 3 shows the wiring inside the device 7 that uses the battery pack 1 as a power source and the method of use when the device is used. Inside the device 7, a positive terminal 3 ″ corresponding to the positive terminal 3 and the negative terminal 4 of the battery pack 1 shown in FIG. 1 and a negative terminal 4 ″ are connected in series and connected to the device circuit 8.

Therefore, by mechanically fitting the battery pack 1 and the device 7, the batteries 2 in the battery pack 1 can be individually discharged in series. As a result, a high voltage can be obtained as a power source, and the efficiency of the motor drive circuit and the like can be improved.

Although an example in which all the terminals are connected in series is shown here, depending on the balance between the required voltage and the required current of the equipment circuit 8, several terminals may be connected in series and further connected in parallel. I don't care.

According to a fifth aspect of the present invention, in the method for using the charging / discharging system according to the fourth aspect, the battery pack has a built-in device for detecting and outputting the battery temperature. The battery pack is characterized by being used intermittently so that the battery pack does not reach a high temperature.

When the battery temperature rises significantly during discharging, such as when a device using the battery pack discharges continuously with a large current of about 10 times the capacity of a single battery, it is desirable to control the battery temperature. Especially when the battery constituting the battery pack is a lithium-ion secondary battery, a marked increase in battery temperature not only lowers battery performance, but may also cause gas generation and liquid leakage.

Therefore, it is preferable to intermittently stop the use when the temperature of the battery pack becomes high due to the device for detecting and outputting the battery temperature.

As a device for detecting and outputting the battery temperature, a conventionally known device such as a combination of a thermocouple and a display device or an irreversible thermolabel having a simple structure can be used.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view of the battery pack in this embodiment. In FIG. 4, in the battery pack, a lithium ion cylindrical secondary battery (diameter 18 mm, battery height 65 m
m, capacity 1200 ± 20 mAh), three batteries are built in, and three positive terminals 9 and three negative terminals 10 corresponding to each battery are provided. The positive terminal 9 and the negative terminal 10 are provided on a charger 11 to be described later and a convex portion 11 provided so as to be fitted to a device. The protruding portion 12 is provided with a protruding portion 12 that is fitted in a charger or a device in reverse so that the positive and negative terminals are not reversely connected.

In order to prevent reverse connection, a method of asymmetrically arranging the positive and negative terminals or changing the shape of the terminal itself depending on whether the terminal is positive or negative may be used.

Further, the battery pack is provided with a pawl 13 and an attachment / detachment button 14 for operating the pawl 13 so as to be fixed when combined with a charger or a device. Then, a reversible thermolabel 15 for detecting that the battery is in a high temperature state and outputting it is attached. This makes it possible to know how many times the built-in battery is used, although the accuracy is not so high.

FIG. 5 is a perspective view of the charger in this embodiment. In FIG. 5, the charger has a concave portion 16 provided so as to be fitted with the convex portion 11, and the positive terminal 9 ′ and the negative terminal 10 are connected so as to be connected to the positive terminal 9 and the negative terminal 10 of the battery pack, respectively. 'Is provided. Further, there is a pawl receiver 17 which is fixed to the pawl 13 so as to be fixed when the battery packs are combined. The operation panel 18 is used to ascertain and operate the state of charge. Charging electricity is taken from the commercial power source by the plug 19. The wiring of the terminals of this charger allows the batteries to be individually charged in parallel as shown in FIG. The voltage of each battery in the battery pack is 4.2V.
The built-in overcharge protection circuit cuts off the battery.

FIG. 6 is a perspective view of an electric screwdriver body as a device in this embodiment. Also in FIG. 6, the electric screwdriver main body has a concave portion 16 ′ provided so as to be fitted with the convex portion 11, and the positive terminal 9 ″ is connected to the positive terminal 9 and the negative terminal 10 of the battery pack, respectively. And a negative terminal 10 '' is provided. Further, there is a pawl receiver 17 'which is joined to the pawl 13 so as to be fixed when the battery packs are combined.

A battery pack is fixed to the main body of the electric screwdriver and used as an electric screwdriver. By pulling the trigger 20, the driver bit 22 attached to the chuck 21 rotates. In the electric driver, each battery is connected in series as shown in FIG.
It is a V drive motor drive circuit. In addition, an over-discharge protection circuit that cuts off when the voltage of the battery pack reaches 7.5 V is built in.

<Comparison Experiment> In order to explain the effects of this embodiment, four battery packs shown in FIG. 4 were prepared and a comparison experiment was conducted.

Lithium-ion cylindrical secondary battery (diameter 18
mm, the height of the battery was 65 mm, and the capacity was 1200 ± 20 mAh. Three batteries (battery 1, battery 2, battery 3) were used to prepare the battery pack A of the embodiment described in FIG. Thermolabel 15 was used for the measurement of the battery temperature during charging and discharging.

The battery pack A is charged using the charger of the embodiment described in FIG. 5, and the electric driver combined with the electric driver body of the embodiment described in FIG. When the operation was performed until the battery voltage reached 7.5 V, the performance equivalent to that of the conventional electric screwdriver using the conventional battery pack was exhibited. The maximum battery temperature at this time was about 50 ° C.

Furthermore, each battery capacity when this cycle was repeated 50 times is shown in (Table 1).

A battery pack B (battery 4, battery 5, battery 6) prepared in the same manner as the battery pack A is charged by the above charger,
Electric discharge was continuously performed until the battery voltage reached 7.5V. The maximum battery temperature at this time was about 90 ° C. Each battery capacity when this cycle was repeated 50 times is shown in (Table 1).

[0039]

[Table 1]

Battery pack B (battery 4, battery 5, battery 6)
It is considered that the large deterioration of the capacity after the cycle is caused by the decomposition of the electrolytic solution and the clogging of the separator due to the increase of the battery temperature. Therefore,
In order to obtain good cycle characteristics, it is desirable to control the battery temperature.

Next, the following comparative experiment was conducted in order to explain the effect when the secondary batteries constituting the battery pack had variations in capacity.

A battery pack C, which is the same as the battery pack A, was prepared except that 1000 mAh (battery 7), 1100 mAh (battery 8) and 1200 mAh (battery 9) batteries having different battery capacities were used. Similar to the battery pack A, this was charged by the charger of this example, and the cycle of intermittent discharge by the electric screwdriver combined with the electric screwdriver main body of this example was repeated 300 times.

Furthermore, 1000 mAh with different battery capacities
(Battery 10), 1100 mAh (battery 11), 1200
A battery pack D equivalent to the battery pack C was prepared using a mAh (battery 12) battery. These are not the charger of this embodiment, but the positive and negative terminals of the battery pack D are connected in series, and then the battery voltage is set to 12.
The battery was charged to 6 V, and similarly to the battery pack A, a cycle of intermittent discharge by an electric screwdriver combined with the electric screwdriver body of this example was repeated 300 times.

The respective battery capacities after these 300 cycles are shown in (Table 2).

[0045]

[Table 2]

The battery pack C (battery 7, battery 8, battery 9) connected in parallel at the time of charging showed good cycle characteristics despite variations in the initial battery capacity, but the batteries connected in series at the time of charging Pack D (battery 10, battery 11,
The capacity of the battery 12) was deteriorated, and the capacity of the battery 10 having a smaller capacity was significantly deteriorated.

It is considered that this is because the battery having a small capacity is overcharged and deteriorated due to the difference in charging depth due to the difference in battery capacity. On the other hand, in the electric screwdriver of this embodiment, since the batteries are individually charged in parallel, the depth of charge is constant for each battery, and therefore the overcharged state does not occur.

[0048]

As described above, according to the charging / discharging system of the present invention, the battery capacities and the battery characteristics are different by connecting the battery packs in parallel when charging and connecting them in series when discharging. This enables stable charge and discharge even when the above occurs.

[Brief description of drawings]

FIG. 1 is a wiring diagram showing wiring of a battery pack of the present invention.

FIG. 2 is a wiring diagram showing wiring of the charger of the present invention.

FIG. 3 is a wiring diagram showing wiring of the device of the present invention.

FIG. 4 is a perspective view of a battery pack according to an embodiment of the present invention.

FIG. 5 is a perspective view of a charger according to an exemplary embodiment of the present invention.

FIG. 6 is a perspective view of an electric screwdriver body according to an embodiment of the present invention.

[Explanation of symbols]

1 battery pack 2 batteries 3, 3 ', 3 "positive terminal 4,4 ', 4 "Negative terminal 5 charger 6 charging circuit 7 equipment 8 device circuits 9, 9 ', 9 "positive terminal 10, 10 ', 10 "negative terminal 11 convex 12 Projection Thirteenth 14 Desorption button 15 Thermo label 16,16 'recess 17,17 'Receptacle 18 Operation panel 19 plug 20 Trigger 21 chuck 22 driver bits

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5G003 AA01 BA05 DA07 FA03                 5H030 AA03 AA04 AS06 BB01 BB21                       BB26 DD02 FF22

Claims (5)

[Claims] 1. A charging / discharging system using a battery pack composed of a plurality of secondary batteries, a charger for charging the battery pack, and a device using the battery pack as a power source, wherein the battery is used. In the pack, positive and negative terminals of the secondary battery are independently provided, the charger is provided with positive and negative terminals corresponding to the positive and negative terminals of the battery pack, and the positive terminal and the negative terminal inside the charger. The devices are connected in parallel, the device is provided with positive and negative terminals corresponding to the positive and negative terminals of the battery pack, and the positive and negative terminals are connected in series only inside the device, or a combination of series and parallel. A charging / discharging system characterized by being connected so as to be connected. 2. The charge / discharge system according to claim 1, wherein the secondary battery is a lithium ion secondary battery. 3. The charging / discharging system according to claim 1, wherein the battery pack has a built-in device that detects and outputs a battery temperature. 4. When using the charging / discharging system according to claim 1, at the time of charging, the secondary battery is charged in parallel by combining the battery pack and the charger,
A method of using a charging / discharging system, characterized in that when the device is used, the battery pack and the device are combined to discharge the secondary battery only in series connection or in combination connection in series and parallel. 5. The battery pack has a built-in device for detecting and outputting a battery temperature, and when the device is used, the battery pack is intermittently used so as not to become a high temperature. How to use the charge / discharge system.