JP2000315505A - Primary battery, secondary battery, charging method and device for secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent producing of dendrite in a secondary battery at charging, preclude deterioration, etc., of the cyclic characteristics of the secondary battery, and hinder the battery capacity from decreasing. SOLUTION: A secondary battery 15 is accommodated in an accommodation part 5 located in a DC magnetic field generated by permanent magnets 11 and 13 of a DC magnetic field generation part. An AC magnetic field generated perpendicular to the DC magnetic filed is impressed on the secondary battery 15 from electromagnets 7 and 9 of an AC magnetic field generation part. With this impression of DC magnetic field and AC magnetic field on the secondary battery 15, vibration is generated in a magnetic filed 23 in a separator 21, and in this condition, charging on the battery 15 is conducted. The vibration of the magnetic powder 23 suppresses deposition of the metal as the negative electrode material likely to be produced in the battery 15 at the time of charging. Accordingly there is no problem even if metal is used as negative electrode material. Because no dendorite is produced at charging even if the thickness of the separator is lessened, this is free of inconvenience such that the battery capacity decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary battery, a secondary battery, a charging device for a secondary battery, and a method for charging a secondary battery.

[0002]

2. Description of the Related Art In a nickel-cadmium storage battery (NiCd battery), which is a kind of secondary battery, the capacity of the cathode side is reduced to suppress generation of hydrogen gas at the cathode and to absorb oxygen gas generated at the anode to the cathode. If it is desired to make the value larger than that on the anode side, a metal is used for the cathode material.

[0003]

When a metal is used as the cathode material, needle-like non-uniform precipitation (dendrites) is liable to occur in the metal when the secondary battery is charged. Eventually, the problem of short-circuit between the anode and the cathode (dendrite short-circuit) due to the growth of the deposited portion and the deterioration of the cycle characteristics of the secondary battery (the number of times charge / discharge can be repeated) will occur. This may occur. Therefore, as a measure for preventing the occurrence of the above-described inconveniences, for example, a method of increasing the thickness of a sheet-like material interposed between the two electrodes, that is, a separator, in order to prevent contact between the anode and the cathode has been studied.

[0004] However, when the thickness of the separator is increased, the above-mentioned problem is less likely to occur, but another problem that the capacity of the battery is reduced occurs.

Accordingly, an object of the present invention is to prevent dendrite from being generated inside the secondary battery during charging, not causing problems such as deterioration in the cycle characteristics of the secondary battery, and reducing the battery capacity. There is to be no.

Another object of the present invention is to provide a primary battery which can easily replace a deteriorated electrolyte part and a cathode with a new electrolyte part and a cathode, and can save resources. Is to do.

[0007]

According to a first aspect of the present invention, there is provided a primary battery comprising: a cassette including an electrolyte portion and a cathode;
It is configured to be detachable from the anode or the battery body.

[0008] According to the above configuration, since the electrolyte section and the cathode are housed in the same cassette, it is easy to replace the deteriorated electrolyte section and cathode with a new electrolyte section and cathode. And resource saving can be achieved.

A secondary battery according to a second aspect of the present invention includes a separator interposed between the two electrodes to prevent contact between the anode and the cathode, and a magnetic powder filled inside the separator.

[0010] A charging device for a secondary battery according to a third aspect of the present invention includes means for generating an alternating magnetic field.

In a preferred embodiment according to the third aspect of the present invention, the alternating magnetic field generating means includes a pair of electromagnets facing each other at a predetermined distance. In the above embodiment, the apparatus further includes means for generating a DC magnetic field in a state orthogonal to the alternating magnetic field. The DC magnetic field generating means includes a pair of permanent magnets facing each other at a predetermined distance, and each permanent magnet is disposed at a position orthogonal to the alternating magnetic field generating means on the same surface as the surface on which the alternating magnetic field generating means is provided. You. Further, a secondary battery housing space is provided at a location defined by the alternating magnetic field generating means and the DC magnetic field generating means.

A method for charging a secondary battery according to a fourth aspect of the present invention is directed to a method for charging a secondary battery having a separator filled with magnetic powder, which is interposed between an anode and a cathode. By applying a DC magnetic field generated in a direction orthogonal to the magnetic field, the secondary battery is charged while the magnetic powder is vibrated.

According to the above configuration, by applying an alternating magnetic field and a DC magnetic field generated in a direction orthogonal to the alternating magnetic field to the secondary battery, the magnetic powder in the separator is vibrated, and in this state, the magnetic powder in the separator is vibrated. The next battery was charged. Therefore, the dendrite (metal deposition) phenomenon that occurs in the secondary battery during charging due to the vibration of the magnetic powder can be suppressed. As described above, since the dendrite phenomenon that occurs inside the secondary battery during charging can be suppressed, metal can be used as the cathode material without any problem. Further, even if the thickness of the separator is reduced, the dendrite phenomenon does not occur at the time of charging. Therefore, there is no problem that the battery capacity is reduced by increasing the thickness of the separator.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing a configuration of a charging device for a secondary battery according to one embodiment of the present invention.

The above device is: As shown in FIG. 1, an alternating magnetic field generation unit 1, a DC magnetic field generation unit 3, and a secondary battery housing unit 5 are provided.

The alternating magnetic field generating unit 1 is opposed to a predetermined distance, and a pair of electromagnets 7, 9 each of which is supplied with an alternating current as an exciting current to a winding, an exciting current control unit and an exciting current supply unit ( (Both are not shown). The DC magnetic field generator 3 includes a pair of permanent magnets 1 facing each other at a predetermined distance.
Each of the permanent magnets 11 and 13 is disposed at a location orthogonal to the electromagnets 7 and 9 on the same plane as the plane on which the electromagnets 7 and 9 are installed inside the apparatus.

The secondary battery accommodating portion 5 is provided with the electromagnets 7, 9 in the same plane as the plane on which the electromagnets 7, 9 and the permanent magnets 11, 13 are installed inside the apparatus.
Is set at a location defined by the permanent magnets 11 and 13. A secondary battery indicated by reference numeral 15 is accommodated in the secondary battery accommodating section 5 as shown in the figure.

In addition, the above-described device has a configuration (not shown) necessary for charging the secondary battery 15 in addition to the above-described components.
Is also provided.

In this embodiment, the secondary battery 15 includes
For example, a nickel-cadmium battery is used.

As shown in the figure, the secondary battery 15 is filled with a magnetic powder 23 in a separator 21 interposed between the electrodes 17 and 19 in order to prevent the anode 17 and the cathode 19 from coming into contact with each other. What was done is adopted.

Next, a method of charging the secondary battery 15 having the configuration in which the separator 21 is filled with the magnetic powder 23 by the apparatus having the above configuration will be described.

First, the secondary battery 15 is housed in the secondary battery housing 5. Thereby, the secondary battery 15 is installed in the DC magnetic field generated by each of the permanent magnets 11 and 13 of the DC magnetic field generation unit 3. In this state, when the exciting current control unit of the alternating magnetic field generating unit 1 controls the exciting current supply unit to supply an alternating current to the windings of the electromagnets 7 and 9, respectively, the orthogonal current to the DC magnetic field is thereby generated. The alternating magnetic field generated in this state is applied to the secondary battery 15.

The application of the DC magnetic field and the alternating magnetic field to the secondary battery 15 causes the magnetic powder 23 in the separator 21 to vibrate. In this state, charging of the secondary battery 15 is performed. Due to the vibration of the magnetic powder 23, the precipitation (dendritic) phenomenon of the metal used as the cathode material that tends to occur inside the secondary battery 15 during charging is suppressed. Therefore, there is no problem even if metal is used as the cathode material. Further, even if the thickness of the separator is reduced, the dendrite phenomenon does not occur at the time of charging. Therefore, there is no problem that the battery capacity is reduced by increasing the thickness of the separator.

FIG. 2 is an explanatory diagram showing advantages and problems when using lithium as a cathode material in a secondary battery.

When lithium is used as the cathode material, as shown in FIG. 2, there is an advantage that a high energy density can be obtained and a low standard oxidation-reduction potential can be obtained. On the other hand, low stability due to short circuit (dendrite short) due to generation of inert lithium inside the battery,
And low charge / discharge efficiency (due to the high reactivity of lithium with the organic electrolyte), such as a short cycle life.

FIG. 3 is a circuit diagram showing the internal configuration of a power supply unit formed by connecting a plurality of secondary batteries and connecting a plurality of primary batteries with the above configuration.

The process of conceiving the power supply unit having the configuration shown in FIG. 3 is as follows.

A secondary battery is mainly used for a portable terminal such as a mobile phone or a mobile computer because it can be charged repeatedly and a relatively large amount of electric power (large current) can be taken out. However, the secondary battery has a shortage of the total power capacity. In particular, in the case of a nickel cadmium battery, there are problems such as a memory effect such as a decrease in the battery capacity due to shallow charge / discharge and a dendrite short circuit described above. Thus, a combination of a secondary battery and a primary battery has led to the recall of a power supply unit that can take advantage of the advantages of both.

First, taking advantage of the feature that a large current can be taken out, the ratio of the secondary battery in the power supply section is reduced to about 1/10, and the primary battery that can take out a small amount of current at a time but has a high energy density is about 9/10. To To prevent the secondary battery from being overcharged or overdischarged, for example, a nickel-cadmium battery (1.
(2V / cell) and four zinc-air batteries. As a result, about five times the capacity can be obtained as compared with the case where the power supply unit is constituted only by the nicd batteries. Further, it is not necessary to provide a DC-DC converter between the primary battery and the secondary battery.

In the power supply section shown in FIG. 3, the total voltage of the nickel-cadmium battery is 1.2V × 5 = 6V, and the total voltage of the zinc-air battery is 1.4 × 4 = 5.6V. When five NiCad batteries and four Zinc air batteries are connected as shown in FIG. 3, the NiCad batteries are charged from the Zinc air batteries. As a result, the voltage value per cell of the NiCad battery becomes Since the voltage is 1.12 V, a stable state can be obtained without overcharging or overdischarging.

Next, the total capacity of the NiCd battery is 170 × 0.1 = 17 Ah, while that of the zinc-air battery is 850 × 0.9 = 765 Ah. Therefore, it is 4.6 times as large as the case of using only the nicd battery. That is, by devising the charging reserve and the like, it is possible to obtain about five times the battery capacity.

According to the above configuration, about five times the energy of the same volume and the same weight can be taken out as a relatively large current, so that a battery (power supply unit) having a higher energy density than an alkaline dry battery or a lithium ion secondary battery can be obtained. realizable. Therefore, as well as the above-mentioned portable terminal, it can be used as a power source for equipment used for a long time without a DC-DC converter.

FIG. 4 is an explanatory view showing a main part of a primary battery according to another embodiment of the present invention.

As shown in FIG. 4, the primary battery according to this embodiment is a cassette 2 including an electrolyte portion 25 and a cathode 27.
9 is configured to be detachable from the anode 31 or the battery body.

According to the above configuration, the electrolyte portion 25 and the cathode 2
7 is housed in the same cassette 29, so that the work of replacing the deteriorated electrolyte part 25 and cathode 27 with a new electrolyte part 25 and cathode 27 can be easily performed.
Moreover, resource saving can be achieved.

Although some preferred embodiments of the present invention have been described above, these are merely examples for describing the present invention, and are not intended to limit the scope of the present invention only to these examples. . The present invention can be implemented in other various forms.

[0038]

As described above, according to the present invention,
At the time of charging, no dendrite is generated inside the secondary battery, no problem such as deterioration of the cycle characteristics of the secondary battery is caused, and the battery capacity is not reduced.

Further, according to the present invention, it is possible to provide a primary battery which can easily replace a deteriorated electrolyte part and a cathode with a new electrolyte part and a cathode and can save resources. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a charging device for a secondary battery according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing advantages and problems when lithium is used as a cathode material in a secondary battery.

FIG. 3 is a circuit diagram showing an internal configuration of a power supply unit formed by connecting a plurality of secondary batteries and connecting a plurality of primary batteries according to one embodiment of the present invention.

FIG. 4 is an explanatory view showing a main part of a primary battery according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alternating magnetic field generation part 3 DC magnetic field generation part 5 Secondary battery accommodation part 7, 9 Electromagnet 11, 13 Permanent magnet 15 Secondary battery 17, 31 Anode 19 Cathode 21 Separator 23 Magnetic powder 25 Electrolyte part 27 Cathode 29 Cassette

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[Procedure amendment]

[Submission date] June 7, 1999 (1999.6.7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

Claims (8)

[Claims] 1. A cassette containing an electrolyte part and a cathode,
A primary battery configured to be detachable from the anode or the battery body. 2. A secondary battery comprising: a separator interposed between two electrodes for preventing contact between an anode and a cathode; and a magnetic powder filled in the separator. 3. A charging device for a secondary battery, comprising: means for generating an alternating magnetic field. 4. The apparatus according to claim 3, wherein said alternating magnetic field generating means includes a pair of electromagnets facing each other at a predetermined distance. 5. The charging device for a secondary battery according to claim 3, further comprising: means for generating a DC magnetic field in a state orthogonal to the alternating magnetic field. 6. The apparatus according to claim 4, wherein the DC magnetic field generating means includes a pair of permanent magnets facing each other at a predetermined distance, and the permanent magnet is provided with the alternating magnetic field generating means. A charging device for a secondary battery, which is arranged at a position orthogonal to the alternating magnetic field generating means on the same surface as the surface to be formed. 7. The secondary device according to claim 3, wherein a secondary battery housing space is provided at a location defined by the alternating magnetic field generating means and the DC magnetic field generating means. Battery charging device. 8. An alternating magnetic field and a DC magnetic field generated in a direction orthogonal to the alternating magnetic field are applied to a secondary battery having a separator filled with magnetic powder, which is interposed between an anode and a cathode. Thereby charging the secondary battery in a state where the magnetic powder is vibrated.