CN1302108A - Electric energy storage device and tool for applying electric energy storage device - Google Patents

Abstract

An electric energy storage device and a tool using the same are provided, the electric energy storage device comprises at least one battery, at least one super capacitor, the internal resistance of which is smaller than that of the battery when the voltage is sufficient, the super capacitor is connected with the battery in parallel, and an output end used for outputting electric energy. Therefore, the super capacitor is a main power supplier for instantly outputting large current, the battery is used for generating power to be supplied to the super capacitor and serves as a secondary power supplier during outputting large current, and a current converter or a current-limiting resistor is not needed between the parallel connection of the battery and the super capacitor.

Description

Electric energy storage device and tool for applying electric energy storage device

The invention relates to an electric energy storage device and a tool using the electric energy storage device, in particular to a rechargeable electric energy storage device applicable to pulsed load current output and a tool using the electric energy storage device.

Currently, portable rechargeable electric tools such as electric drills, electric saws, or electric nailers require an electric energy storage device as an electric energy supply source. As shown in FIG. 1 , a conventional electric energy storage device 1 includes a plurality of batteries 2 connected in series and an electric energy output terminal 3 . The plurality of batteries 2 connected in series is used to meet the requirement of the working voltage. At present, the battery 2 mainly uses nickel-cadmium batteries, because nickel-cadmium batteries can be used for high-current discharge, and can output a large current output equivalent to about 20 times the capacity value in an instant, which is suitable for the output of pulsed load current, but due to the nickel-cadmium battery The energy density of the battery is insufficient, so the weight is large and the working time is short. Although lithium batteries have the advantages of light weight and high energy density, they are not suitable for high-current discharge, so they are not suitable for pulse-type load current output applications. Therefore, at present, both the electric energy storage device and the portable electric tool using the electric energy storage device have the disadvantages of heavy weight and short working time.

Furthermore, conventional electric energy storage devices and portable electric tools are also limited by the characteristics of secondary batteries. In addition to the inability to quickly release electric energy and the limited power output, when their applications require instantaneous large battery output, there will be More problems, such as high power output will reduce the power and cycle life of the secondary battery, and the battery is often charged due to incomplete discharge, causing the capacity of the battery with memory effect to decay quickly, and eventually the life is shortened.

In order to meet the requirement of instantaneous large current output, a battery combined with a capacitor is a feasible solution. A battery can store a large amount of electrical energy, but it cannot release it quickly, and its output power is limited. On the other hand, a capacitor can provide a large current, but it cannot last for a long time, and its energy density is much lower than that of a battery. Among them, supercapacitors are especially suitable for pulsed load current output applications due to their higher power, voltage and energy density than ordinary capacitors. In the electric energy storage device composed of a battery and a supercapacitor, the battery is mainly responsible for charging the supercapacitor, while the high current output is supplied by the supercapacitor; in this way, different batteries can be used, and the life and utility of the battery can be ensured .

Figures 2 and 3 show how conventional batteries are connected to supercapacitors. Before the battery 2 is connected in parallel with the supercapacitor 4, a converter 5 must be provided as shown in Figure 2, or a diode 6, a current-limiting switch 7 and a current-limiting resistor 8 must be provided as shown in Figure 3 to prevent the supercapacitor from exploding. Disadvantages of electrical energy storage devices are high cost, complicated and difficult installation.

The purpose of the present invention is to provide a high-efficiency, long-life electric energy storage device, which can provide instantaneous high power output, and at the same time take into account the requirements of prolonging the use time, so that not only the battery capacity can be fully utilized but also the battery life can be extended, and the cost is reduced. Low, simple installation.

Another object of the present invention is to provide an electric energy storage device, which increases the types of batteries suitable for high power output, not limited to the use of nickel-cadmium batteries, but also enables high-energy batteries such as nickel-metal hydride batteries, lithium-ion batteries, and lithium polymer batteries. High-performance batteries with high density can be used directly without any design changes; even ordinary batteries do not need to sacrifice their energy density in order to increase power density.

Another object of the present invention is to provide an electric energy storage device, which is light in weight, high in capacity, and can be used more often without memory effect.

Another object of the present invention is to provide a portable electric tool using an electric energy storage device, which mainly utilizes the above electric energy storage device and has the benefits provided by the electric energy storage device.

To achieve the above object, the electric energy storage device of the present invention includes at least one battery, at least one supercapacitor, and an electric energy output terminal, the internal resistance of the supercapacitor when the voltage is sufficient is smaller than the internal resistance of the battery, and the supercapacitor is connected in parallel with the battery.

In the electric energy storage device, the battery is composed of a plurality of batteries connected in series.

In the electric energy storage device, the battery is a lithium battery.

In the electric energy storage device, the battery is a nickel-cadmium battery.

In the electric energy storage device, the battery is a nickel-zinc battery.

In the electric energy storage device, the battery is a nickel-metal hydride battery.

The electric energy storage device also includes a battery protection control mechanism and a bidirectional current power switch connected in series with the battery.

The electric energy storage device also includes a zener diode connected in parallel with the supercapacitor.

A tool using an electric energy storage device according to the present invention includes a tool body; and an electric energy storage device for supplying electric energy to the tool body, the electric energy storage device includes at least one battery, at least one supercapacitor and an electric energy output terminal , the internal resistance of the supercapacitor is smaller than the internal resistance of the battery when the voltage is sufficient, and the supercapacitor is connected in parallel with the battery pool.

In the tool using the electric energy storage device, the battery is composed of a plurality of batteries connected in series.

In the tool using an electric energy storage device, the battery is a lithium battery.

In the tool using an electric energy storage device, the battery is a nickel-cadmium battery.

In the tool using an electric energy storage device, the battery is a nickel-zinc battery.

In the tool using an electric energy storage device, the battery is a nickel-metal hydride battery.

The tool using the electric energy storage device also includes a battery protection control mechanism and a bidirectional current power switch connected in series with the battery.

The tool using the electric energy storage device further includes a zener diode connected in parallel with the supercapacitor.

After adopting the above-mentioned structure, in the electric energy storage device of the present invention, the internal resistance when the supercapacitor voltage is fully charged is smaller than the internal resistance of the battery, and is connected with the battery in parallel, and outputs electric energy through an output terminal; Therefore, the supercapacitor is the main power supplier for instantaneous large current output, and the battery is used to generate power for the supercapacitor, and serves as a secondary power supplier during high current output. There is no need for a converter or a current-limiting resistor between the parallel connection of the battery and the supercapacitor, so the electric energy storage device has high efficiency, long life and simple device.

In the present invention, the battery is not limited by type, and can be a nickel-cadmium battery, a nickel-hydrogen battery or a lithium battery, preferably a lithium battery, which is light in weight, high in capacity, long in service time, many times in use and avoids memory effect .

The electric energy storage device of the present invention also includes a battery protection control mechanism and a bidirectional current power switch connected in series with the battery, and the battery protection control mechanism is used to control the opening and closing of the bidirectional current power switch to prevent the battery from being damaged. overcharge, overdischarge, and avoid operating at large discharge currents.

The electric energy storage device of the present invention also includes a zener diode connected in parallel with the supercapacitor to prevent the supercapacitor from operating under overvoltage conditions and prevent the electric energy storage device from operating under overcurrent conditions.

In the case of common instantaneous large current discharge and inseparable utilization of the electric energy storage device, the present invention also provides a tool using the electric energy storage device, which includes a tool body and a device for supplying electric energy to the tool body The above-mentioned electric energy storage device, the application equipment has various advantages of the above-mentioned electric energy storage device.

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail

FIG. 1 is a schematic circuit diagram of a conventional electric energy storage device using nickel-cadmium batteries.

FIG. 2 is a schematic circuit diagram of a connection method between a battery and a supercapacitor in a conventional electric energy storage device.

FIG. 3 is a schematic circuit diagram of a connection method between a battery and a supercapacitor in a conventional electric energy storage device.

FIG. 4 is a schematic circuit diagram of a supercapacitor.

Figure 5 is a schematic circuit diagram of the battery.

FIG. 6 is a schematic circuit diagram of a preferred embodiment of the electric energy storage device of the present invention.

Fig. 7 is a waveform diagram of the voltage of the electric energy storage device and the output current of the entire electric energy storage device changing with time when the electric energy storage device of the present invention is used in an electric tool.

Fig. 8 is a waveform diagram of the voltage of the electric energy storage device and the output current of the battery changing with time when the electric energy storage device of the present invention is used in an electric tool and the screw comes out.

Fig. 9 is a waveform diagram of the voltage and output current of the electric energy storage device changing with time when the electric energy storage device of the present invention is applied to an electric tool when the screw is screwed in.

Fig. 10 is a waveform diagram of the voltage of the electric energy storage device and the output current of the battery changing with time when the electric energy storage device of the present invention is applied to an electric tool when the screw is turned in.

The so-called supercapacitor refers to the application of a double-layer structure, and the electrode is formed by a special process, such as a honeycomb structure, to increase the surface area per unit weight; its capacitance value often reaches one or several Farad values, far exceeding the general electrophoresis The capacity of the capacitor used in the capacitor is also called a farad capacitor or a double-layer ultra-high capacitor. The energy stored in it can be released in an instant. It is generally believed that the internal impedance of supercapacitors is very low. If they are directly connected in parallel with batteries, a huge charging current will be generated, causing damage to or even explosion of the batteries or capacitors.

A general capacitor, such as an electrolytic capacitor, can be regarded as an ideal capacitor connected in series with a series resistor and a parallel resistor. If the current passing through the capacitor is too large, the heat generated by the Joule effect will heat the electrolyte in the capacitor. As a result, the parallel resistance value decreases, and the material deteriorates and explodes.

In fact, it can be known from the embodiments of the present invention that the structure of a supercapacitor is different from that of a general capacitor and is closer to a lithium battery, so its internal resistance can be adjusted with changes in service conditions, and there will be no general impact on a properly matched battery system. The expected result of a battery explosion. According to a design rule, the battery and the supercapacitor can be directly connected in parallel without a converter or a current limiting mechanism; the internal impedance of the supercapacitor will change with the discharge of the supercapacitor, as shown in Figure 4 on the circuit, When the voltage of the supercapacitor is fully charged, the internal resistance is almost equal to R1, but when the supercapacitor starts to discharge, the effects of the resistors R2 to R5 in Figure 4 will appear, and the internal resistance of the supercapacitor will gradually increase.

Compared with the supercapacitor, the internal resistance RB of the battery is almost constant during the discharge period, which can be illustrated by the model in Figure 5 on the circuit.

The design rule shows that, as shown in Figure 4, R1 represents the internal resistance of the supercapacitor 4 when it is fully charged, as long as R1 is smaller than the internal resistance RB of the battery 2, as shown in Figure 5, the supercapacitor 4 can be directly connected in parallel with the battery 2 without Requires an inverter or current limiting mechanism. In the initial stage of discharge, most of the discharge current will be supplied by the supercapacitor, but after a period of discharge, the total internal resistance of the supercapacitor will increase, making the discharge current smaller. When the total internal resistance of the supercapacitor rises to more than When the internal resistance of the battery is RB, the battery will automatically charge the supercapacitor.

For the direct parallel connection of the supercapacitor and the battery, the method proposed by the present invention is to charge the supercapacitor before connecting the supercapacitor in parallel with the battery, so that the voltage of the supercapacitor rises to be close to the voltage of the battery, and then connect the supercapacitor in parallel with the battery. The battery can be one or several in series, depending on the working voltage. Because the voltage of the supercapacitor is very close to the voltage of the battery, the charging current of the battery to the supercapacitor will not be very large, and there is no need for an external converter or a current-limiting resistor between the two. In other words, as long as the supercapacitor is charged first, so that the battery and the supercapacitor will not generate extremely high current in an instant, the current relationship between the two will reach a balance, and there is no need to add a conventional inverter between the two and other circuits.

As long as the internal resistance RB of the supercapacitor and the battery is properly selected so that R1 is smaller than RB, the instantaneous large current will be automatically supplied by the supercapacitor. Charging, the whole system can output instantaneous high current, and the battery can completely release the stored electric energy.

A preferred embodiment of the electric energy storage device of the present invention is shown in FIG. 6 . When the electric energy storage device is applied to a rechargeable electric tool such as a portable electric drill, the load condition usually requires a high pulsed current. When the load needs a large current, the super capacitor 4 in the electric energy storage device 1 supplies the load for a period of time, and the secondary lithium battery 2 is used to store electric energy. When the super capacitor 4 exhausts most of the electric energy, the two The secondary lithium battery 2 charges the supercapacitor 4 to store electric energy to supply the next wave of high pulse current. Because the lithium battery 2 does not perform high-current instantaneous discharge, the service life of the lithium battery can be increased.

Due to the higher energy density of the lithium battery, the weight of the lithium battery in the electric energy storage device is lighter than that of the conventional nickel-cadmium battery, so the total power density (output power per unit weight) of the electric energy storage device of the present invention will increase a lot.

Those of ordinary skill in the industry know that the batteries in the electric energy storage device may include various forms of secondary batteries, as well as general non-rechargeable batteries.

Considering the protection of the battery, another preferred embodiment of the present invention can also include a battery protection control mechanism 10 and a bidirectional current power switch 11 connected in series with the lithium battery 2, and these mechanisms can protect the lithium battery 2 from being damaged. overcharging. When the electric energy storage device 1 is charging, if the voltage of any lithium battery 2 exceeds the rated value, the control mechanism 10 will send a signal to the bidirectional current power switch 1 to cut off the path of the charging current so that the lithium battery 2 is no longer charged; Furthermore, these devices can also protect the lithium battery 2 from being over-discharged. When the electric energy storage device is discharging, if the voltage of any lithium battery 2 is lower than the rated voltage, the control mechanism 10 will send a signal to the bidirectional current power switch 11. Cut off the discharge current path so that the lithium battery 2 is no longer discharged; and, these mechanisms can also protect the lithium battery from operating under a large discharge current. When the electric energy storage device is discharging, if the discharge current exceeds the rated , the control mechanism 10 will send a signal to the bidirectional current power switch 11 to cut off the path of the discharge current so that the lithium battery is no longer discharged.

Considering the protection of the supercapacitor 4, the preferred embodiment of the present invention also includes a Zener diode 9 and a resettable fuse 12, which protect the supercapacitor 4 from operating under overvoltage conditions: if the voltage of the supercapacitor 4 exceeds the Zener diode 9, the zener diode 9 will conduct, so that the current flows through the zener diode 9, so as to ensure that the supercapacitor 4 will not operate under overvoltage conditions; and, it will protect the electric energy storage device 1 from Operation under overcurrent conditions: the self-resetting fuse 12 is a resistor with a positive temperature coefficient. When the current of the electric energy storage device 1 is too large, the temperature of the self-resetting fuse 12 will rise, and the resistance will become too large to cut off the current , so as to ensure that the electric energy storage device will not operate under over-current and over-temperature conditions.

The electric energy storage device mentioned above can be rotated by an electric drill to unscrew it and screw it into the wooden board to measure the voltage and current of the battery and its waveform.

1. Experimental instruments and tools are as follows:

KUMAS KD3643A DC7.2V Portable Electric Drill

18650 battery

ELNA 2.5V 50F super capacitor

TEKTRONIX Current Probes

YOGOGAWA Oscillator Observer

Connection method: Use the connection method shown in Figure 6. The battery pack is composed of two 18650 batteries connected in series, and the capacitor group is composed of three 2.5V, 50F supercapacitors connected in series, and a protection mechanism is added.

2. The experimental results are as follows:

A． screw out

The current waveform consumed by turning the screw is shown in Figure 7, where the filtering of the filter is none, and the bandwidth is all; the bias is 0.00V in the first channel, and 0.00V in the second channel; the record length is basically 10K, its image enlargement is 10K; the trigger mode is single, its typing is on the side of the second channel, the delay is 0 nanoseconds, and the spacing is the smallest; the time interval is 0.5 seconds per grid, and the upper half of the picture is an electric energy storage device Voltage, 5 volts per grid; the lower half of the figure shows the output current of the entire electrical energy storage device, 10 amps per grid. The current is the highest at the beginning, when the screw has been turned out, the required torque has been reduced, so the current consumption is getting smaller and smaller.

The output current of the lithium battery 2 is shown in Figure 8, wherein the filtering of the filter is none, and the bandwidth is all; the bias is 0,00V in the first channel, and 0,00V in the second channel; the record length is basically 10K , its image enlargement is 10K; the trigger mode is single, its typing is on the side of the second channel, the delay is 0 nanoseconds, and the spacing is the smallest; the time interval is 0.5 seconds per grid, and the upper half of the picture is the electric energy storage device Voltage (5 volts per grid); the lower half of the figure is the output current of lithium battery 2 (10 amperes per grid). It can be seen that the average output current of the lithium battery 2 is less than 2A, indicating that the supercapacitor 4 supplies most of the output current of the entire electric energy storage device 1 .

B． screw in

The current waveform consumed by turning the screw in is shown in Figure 9, where the filtering of the filter is none, and the bandwidth is all; the bias is 0.00V in the first channel, and 0.00V in the second channel; the record length is basically 10K, its image enlargement is 10K; the trigger mode is single, its typing is on the side of the second channel, the delay is 0 nanoseconds, and the spacing is the smallest; the time interval is 0.5 seconds per grid, and the upper half of the picture is an electric energy storage device 1 voltage, 5 volts per grid; the lower half of the figure shows the output current of the entire electric energy storage device 1, 10 amperes per grid. At the beginning, the motor of the electric drill needs to be started, so there is a high current for a moment, and then when the screw is turned in, the required torque is getting bigger and bigger, so the current consumption is getting bigger and bigger.

The output current of the lithium battery 2 is shown in Figure 10, wherein the filtering of the filter is none, and the bandwidth is all; the bias is 0.00V in the first channel, and 0.00V in the second channel; the record length is basically 10K , its image enlargement is 10K; the trigger mode is single, its typing is on the side of the second channel, the delay is 0 nanoseconds, and the spacing is the smallest; the time interval is 0.5 seconds per grid, and the upper half of the picture is the electric energy storage device 1 is the voltage; 5 volts per grid, and the lower half of the figure shows the output current of the lithium battery 2, 10 amperes per grid. It can be seen that the average output current of the lithium battery 2 is less than 2A, indicating that the supercapacitor supplies most of the output current of the entire electric energy storage device 1 .

Claims (16)

1. An electric energy storage device, comprising at least one battery, at least one supercapacitor, and an electric energy output terminal, characterized in that: the internal resistance of the supercapacitor when the voltage is sufficient is smaller than the internal resistance of the battery, and the supercapacitor uses connected in parallel with the battery. 2. The electric energy storage device according to claim 1, wherein the battery is composed of a plurality of batteries connected in series. 3. The electric energy storage device according to claim 1 or 2, wherein the battery is a lithium battery. 4. The electric energy storage device according to claim 1 or 2, wherein the battery is a nickel-cadmium battery. 5. The electrical energy storage device according to claim 1 or 2, wherein the battery is a nickel-zinc battery. 6. The electric energy storage device according to claim 1 or 2, wherein the battery is a nickel metal hydride battery. 7. The electric energy storage device according to claim 1, further comprising a battery protection control mechanism and a bidirectional current power switch connected in series with the battery. 8. The electric energy storage device as claimed in claim 1, further comprising a Zener diode connected in parallel with the supercapacitor. 9. A tool for applying an electrical energy storage device, comprising: a tool body; and an electrical energy storage device for supplying electrical energy to the tool body, the electrical energy storage device comprising at least one battery, at least one supercapacitor and an electrical energy output terminal, It is characterized in that: when the voltage is sufficient, the internal resistance of the supercapacitor is smaller than that of the battery, and the supercapacitor is connected with the battery pool in parallel. 10. The tool using an electric energy storage device as claimed in claim 9, wherein the battery is composed of a plurality of batteries connected in series. 11. The tool for applying electric energy storage device according to claim 9 or 10, characterized in that the battery is a lithium battery. 12. The tool using an electric energy storage device according to claim 9 or 10, wherein the battery is a nickel-cadmium battery. 13. The tool using an electric energy storage device as claimed in claim 9 or 10, wherein the battery is a nickel-zinc battery. 14. The tool using an electric energy storage device as claimed in claim 9 or 10, wherein the battery is a nickel metal hydride battery. 15. The tool using an electric energy storage device as claimed in claim 9, further comprising a battery protection control mechanism and a bidirectional current power switch connected in series with the battery. 16. The tool using an electric energy storage device as claimed in claim 9, further comprising a Zener diode connected in parallel with the supercapacitor.

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