JP2010158129A - Charging method and charging device of secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging method of a secondary battery which can expand an objective range of quick charging and short-time charging by constant-current charging, can accelerate charging speed, and can prevent abrupt change of charging properties in the middle of charging, and to provide a device for charging the battery. <P>SOLUTION: The charging method of the secondary battery is such that a pulse-state voltage (particularly, a pulse-state voltage of a positive-potential voltage waveform) is periodically superimposed on a charging voltage of the constant-current charging, and applied to the secondary battery. The charging device of the secondary battery is such that a charging circuit having a circuit means of the constant-current charging includes a control means which controls the generation of the pulse-state voltage caused by the accumulation and the discharging of exciting energy to a coil of the charging circuit, by feeding a direct current to the coil; and the pulse-state voltage which is generated due to the feed control of the direct current by the control means is periodically superimposed on the charging voltage of the constant-current charging, and applied to the secondary battery. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

According to the present invention, the flow (supply) of regular charges to the in-battery chemical system by constant current charging is affected by the charging voltage due to the periodic superposition of pulsed voltages, and thereby the normal constant current charging is performed. Charging characteristics (for example, prevention of sudden jumps during charging during quick charging and short-time charging, etc.) are manifested and smooth charging progress and faster charging (especially rapid charging / The present invention relates to a method for charging a secondary battery and a charging device for the same, which enables high-speed short-time charging.

A secondary battery has at least a positive / negative electrode and an ion-conducting electrolyte as components, and has a mechanism that can be recharged / discharged by mutual conversion between chemical energy and electrical energy through the electrochemical reaction of the battery. Then, it is used as a power source for various industrial equipment (for example, electronic equipment, computer equipment, precision equipment, transportation equipment, etc.).
The “secondary battery” is used in a broad sense including a single secondary battery and an assembled battery (an assembly of a plurality of secondary batteries) in a broad sense, and a single secondary battery in a narrow sense. Used in the meaning of a battery. In the claims and the present specification, the term “secondary battery” is used in a broad sense, and when used in the meaning of a single secondary battery or assembled battery in a narrow sense, it is referred to that effect. To do. In the following, “secondary battery” is abbreviated as “battery”, and “secondary battery” is used when particularly necessary.
In the present specification and claims, the term “positive electrode” and “negative electrode” of a battery are used in the meaning of the electrode on the side where current flows from the battery to an external circuit during discharge, and “negative electrode” It is used in the meaning of the electrode on the side where current flows into the battery from the external circuit.
“Charging efficiency” is used herein in the meaning of ampere / hour efficiency.
In this specification, “charging characteristics” are physicochemical and electrical characteristics that appear in a battery due to the action of a reaction system in the battery during charging, and are observable or measurable characteristics (for example, battery voltage, battery temperature, battery Used in the meaning of voltage.
Batteries have increased capacity, downsizing, higher performance, and charging due to diversification, higher performance, and downsizing (ie, reduction in battery mounting space) of the equipment to be mounted. There is a demand for shortening of time, reduction of heat generation, safe and accurate control, and downsizing of devices.
Practical batteries are mostly lead batteries, nickel / cadmium batteries, nickel / hydrogen batteries, and lithium batteries. Besides these, nickel / metal hydride batteries, manganese dioxide / lithium batteries, nickel / zinc batteries Silver / zinc batteries are in practical use.

Charging of a battery is a process of returning an active material to a dischargeable state by a complex chemical reaction system by supplying electricity from an external power source, and the contents thereof include the electrode surface by the active material (also called an active material) and the There are various physicochemical phenomena such as complex electrochemical reactions in the vicinity, adsorption / desorption of reaction-related substances on the electrode surface, ion transfer in the electrolyte, heat generation and heat absorption in the reaction system, and gas generation / absorption. They are intricately affecting each other.
Charging a battery consists of supplying a current from an external power source to the battery and ending the supply of current (generally called charging end). The end of charge theoretically means a state of complete charge (a state where the charge capacity is 100% charged). The term “full charge” is used as a synonym for “full charge”.
However, in practical charging, there are many cases where charging ends when the charging capacity is less than 100%.
As a method for charging a battery, a method of supplying direct current or intermittent current (alternating current and other intermittent current) has been proposed, and in practical charging, charging by direct current that makes it easy to check and check the amount of charge is common. . In quick charging (charging within 1 hour), charging is generally performed by direct current. Charging by alternating current and intermittent current is charging with the main purpose of performing energization on / off and obtaining the effect generated in the battery by the energization off time, and is limited to charging that prevents the generation of dent light. (See, for example, Patent Documents 1 to 4).
In the charging method in which intermittent current is turned on / off and the peak voltage value is increased to increase the amount of current flowing between them and the subsequent off time is extended to prevent battery damage, the battery voltage is increased abnormally and Battery deterioration has occurred (see Patent Document 6).

Charging by direct current includes a method of flowing a direct current of a constant current value (A, mA) (“constant current charging” is used) and a method of flowing a direct current of a constant voltage value (V) (“constant voltage charging”). Is a conventional charging method, and in particular, constant current charging is a charging method having versatility. Note that “constant current charging” is a technical term used in the same meaning in a book (charging technical book) and a dictionary.
The versatility of constant current charging is due to industrial conveniences such as easy handling of charging of different types of batteries, easy control and charge amount confirmation, and simplification and miniaturization of the charging device.

FIG. 12 is an explanatory diagram schematically showing charging characteristics of constant current charging (see, for example, p413 of Non-Patent Document 1).
In constant current charging, a direct current is maintained at a constant current value and supplied to the battery. To maintain the constant current value, control is performed to increase the voltage of the supplied direct current so as to maintain the voltage difference from the battery voltage that increases as the charging progresses. Therefore, when the charging voltage for maintaining a constant current exceeds the allowable upper limit voltage of the battery, the constant current charging is terminated at that time.
Constant current charging is classified according to charging time into quick charging (charging within 1h), short-time charging (charging within 3-8h) and normal charging (charging within 8-18h) (for example, non-charging) (See Table 5.9 on page 188 of Patent Document 3) In practical charging, there is a high demand for quick charging and short-time charging (particularly, rapid charging).

Although constant current charging is general-purpose, there are cases in which charging characteristics are significantly different depending on the type of battery, and charging cannot be performed until the end of charging due to a set constant current value. In that case, maintaining constant current charging by changing the set current value during charging (for example, two-step current charging) and changing from constant current charging to constant voltage charging during charging (for example, constant current constant voltage) Charging) and the like.

FIG. 13 is an explanatory view schematically showing charging characteristics of constant voltage charging (see, for example, p414 in Non-Patent Document 1). Since constant voltage charging is set and maintained at a constant charging voltage (V) by control, the voltage difference between the battery voltage rising due to charging and the set charging voltage value decreases, and the charging current value attenuates. In constant voltage charging, the charging voltage is maintained at a constant value by control, so that the upper limit voltage maintenance is strictly regulated to prevent accidents (for example, lead batteries, zinc / manganese dioxide batteries, lithium batteries, etc.) It is suitable for charging because it is easy to maintain the upper limit voltage.

In constant voltage charging, since the battery voltage becomes extremely low and a large current flows at the beginning of charging, a limiting circuit that restricts the large current at the beginning of charging becomes essential, which interferes with the control of the charging voltage. Therefore, proper control of the charging voltage becomes difficult.
Moreover, in the constant voltage charging, it is necessary to accurately predict the battery voltage at the end of charging in advance and set the charging voltage. However, since the battery voltage during charging varies irregularly due to temperature changes around the battery during charging and battery heat generation, it is extremely difficult to accurately predict the battery voltage at the end of charging in advance. Is difficult to perform accurately (see, for example, P150 of Non-Patent Document 5).

FIG. 14 is an explanatory diagram schematically showing charging characteristics when a sealed lead-acid battery is rapidly charged with constant voltage charging at three set voltages (2.70 V, 2.55 V, and 2.35 V) (for example, non-patent) (Refer to p441 in Reference 1).
In FIG. 14, in any of the charging of symbols A, B, and C, a large current flows in 2 to 3 minutes in the initial stage of charging, and almost reaches a charge amount of 100% within 30 minutes of the first half of charging.
Therefore, in fast charging with constant voltage charging, the amount of charge reaches almost 100% due to a large current flowing in the initial 2-3 minutes, so a high charging voltage setting that allows a large current in the initial charging is allowed. Limited to batteries. On the other hand, the charging characteristics of constant current charging are significantly different depending on the battery type.

FIG. 15 is an explanatory diagram showing the relationship between the battery voltage vs. charge capacity% when different types of batteries are charged with constant current (20 ° C.), and shows the same charge rate (0.1 × C) and approximate charge rate. Even with constant-current charging (20 ° C), if the battery type is different, the contents of the reaction system in the battery during charging are significantly different, thereby showing data in which the battery voltage vs. charge capacity% is significantly different. (See P355 of Non-Patent Document 1). Similar figures are also shown in Non-Patent Documents 2 and 3.

The charging characteristics of FIG. 15 are data of constant current charging (20 ° C.) with a general charging rate (mostly 0.1 × C) in normal charging (charging for 8 to 18 hours). The charging rate “C” means capacity. “Charge rate” is also called “time rate”, and is a common term used for books and dictionaries. The claims and the specification use “charge rate”.
In FIG. 15, “capacity” on the horizontal axis means the amount of electricity contained in the battery, and is displayed in units of coulomb (C) or ampere-hours (Ah, mAh).

Note that the actual capacity at the time of charging is considerably reduced compared to the theoretical capacity. Therefore, in practical batteries, the capacity is often displayed as a rated capacity or a nominal capacity (see, for example, Non-Patent Document 3).
“50% by volume” on the horizontal axis in FIG. 15 is based on full charge (ie, 100% by volume). “50% by volume” indicates that 50% of the full charge is charged. ing.

For normal charging (8-18h charging), a charging rate of about 0.1-0.3C is generally adopted, and quick charging (charging within 1h) is 10 times the normal charging (for example, 1-3C) In general, 0.2 to 0.4 C is employed for short-time charging (charging for 3 to 8 hours) (see, for example, p188 of Non-Patent Document 3).
The chemical symbol (for example, Ni—Cd) in FIG. 15 indicates the type of the battery with a chemical symbol. For example, “Ni—Cd” indicates a sealed nickel-cadmium battery. The sealed type is an operation type battery that absorbs gas generated from an electrode with an opposite electrode.
In the sealed nickel-cadmium battery of FIG. 15, the battery voltage changes most gently during constant current charging at a charging rate of 0.1 C, and the battery temperature also rises near the end of charging. The sealed nickel / cadmium battery and the sealed nickel / hydrogen battery are batteries of an operation system (hereinafter, abbreviated as a cathode absorption system in some cases) that absorbs gas generated from the positive electrode at the end of charging at the cathode.
Cathode absorption type batteries are known to exhibit remarkably different charging characteristics compared to normal charging in short-time charging or rapid charging.

FIG. 16 is an explanatory diagram showing charging characteristics when a sealed nickel-cadmium battery is charged with constant current at different charging rates (see p484 of Non-Patent Document 1).
In a sealed nickel-cadmium battery, when charging at a normal charging rate of 0.1 (C / 10) C, the battery temperature rises rapidly from near the end of charging, and the battery voltage rises gradually throughout the charging.
On the other hand, at a charge rate (short-time charge) of 0.3 (C / 3) C, the battery temperature and the internal pressure of the battery rapidly rise to the overcharge region in the vicinity of approximately half the charge amount of full charge. The sudden rise in battery temperature that occurs at the end of charging at a charging rate of 0.1 (C / 10) C (normal charging) of a cathode absorption type battery is generated from the positive electrode due to the corresponding calorific value of the battery. In general, it is considered to be due to a change in enthalpy of an absorption reaction (which becomes an exothermic reaction) by a gas cathode.
However, the behavior of the chemical reaction system in the battery that causes a rapid increase in battery temperature at approximately half the charge of full charge in charging at a charging rate of 0.3 C short-time charging has not been clarified.

For this reason, in sealed nickel / cadmium batteries for rapid charging, battery structure improvements and changes in battery pressure, battery temperature, battery voltage, etc. are required to prevent damage and destruction of the battery due to sudden increases in charging characteristics. A mechanism for improving the detection accuracy and making the control unit of the CPU a complicated circuit configuration and determining the end of charging with high accuracy is required.
Improvement of the battery structure is, for example, suppression of an increase in the internal pressure of the battery due to an increase in the amount of gas absorption at the cathode due to an increase in the area of the cathode that absorbs the gas, and a structure in which the internal structure can withstand overcharge.
Generally, a sealed nickel / cadmium battery has a battery performance / battery life that is lowered when the temperature exceeds 30 ° C., and battery performance is deteriorated due to excessive overcharge. Further, if the battery temperature becomes too high, the charging current value increases and a heat dissipation state occurs, resulting in damage to the battery.
FIG. 17 is an explanatory diagram showing the relationship between the battery ambient temperature and the battery life during charging / discharging of a sealed nickel-cadmium battery (see P218 of Non-Patent Document 2), and 30 sealed nickel-cadmium batteries are used. It is shown that the battery life is reduced even when exposed to temperatures in the vicinity of ° C., and that the battery life is significantly reduced when the exposed temperature is increased. However, no effective proposal for preventing an increase in battery ambient temperature during charging / discharging (particularly charging) has not been proposed.

The sealed nickel-hydrogen battery in FIG. 15 is a battery having the same operating principle as the sealed nickel-cadmium battery, and can be rapidly charged by constant current charging. However, even in nickel-hydrogen batteries, rapid changes in battery voltage, battery temperature, and battery pressure occur due to rapid charging. Means for avoiding this include an increase in the gas absorption area at the cathode due to an increase in the cathode area, an improvement in the temperature resistance of the battery structure, and an improvement in the accuracy of the end of charging.
Many of the types of batteries shown in Fig. 15 suddenly increase the battery voltage, battery temperature, and pressure inside the battery and exceed the allowable upper limit. There are many types of batteries.

Japanese Patent Laid-Open No. 06-36803 Japanese Patent No. 4039571 Japanese Patent No. 4016200 Japanese Patent No. 3700288 Japanese Patent No. 3438340 Japanese Patent No. 4079590

By David Linden &#8943; edited by Tsutomu Takamura &#8943; supervised translation: [Latest secondary battery handbook] Asakura Shoten December 20, 1996 First edition 1st edition issued Maruzen Co., Ltd .: [Battery Handbook 3rd Edition] Maruzen Co., Ltd. issued on February 20, 2000 Nihon Batteries Co., Ltd .: Hen [Latest Practical Secondary Batteries-Second Edition-How to Select and Use] Nikkan Kogyo Shimbun May 31, 2001 Second Edition, 2nd edition Transistor Technology Editor: Edition [Secondary Battery Application Handbook] CQ Publishing Co., Ltd. April 1, 2005 Second Edition issued Akiyoshi Nishimura: Work [Revised Battery Book] CQ Publishing Co., Ltd. July 15, 1996 Revised 1 edition issued

Various problems such as the following (A) to (G) exist in constant current charging (particularly, rapid charging and short-time charging).
(A) In constant current charging, there are many types of batteries whose charging characteristics change suddenly during charging even during normal charging (charging for 8 to 18 hours) (see FIG. 17). There are many types of batteries that cannot be charged on an industrial scale.
(B) In rapid charging and short-time charging by constant current charging, the battery temperature rapidly rises at the stage of approximately half the amount of full charge, and the battery temperature exceeds the temperature range around 30 ° C for each repeated charge. Battery life is reduced (see Figure 17).
(C) In fast charging and short-time charging by constant current charging, in order to have a structure that can withstand a sudden increase in battery temperature, battery internal pressure, etc. during charging, a battery (particularly a battery of a cathode absorption system, etc.) and Modifications such as increasing the strength of the electrode are required.
(D) In rapid charging and short-time charging by constant current charging, the slight change in charging characteristics that leads to the end of charging is accurately captured in order to avoid runaway due to sudden rises in battery voltage, battery temperature, and battery pressure. It is essential to end charging. In particular, a battery of a cathode absorption type or the like has low resistance to a sudden runaway, and therefore, a precision of determination at the end of charging is required.
For this reason, a charging device that performs quick charging and short-time charging requires a complicated and special control circuit that precisely observes, predicts, and determines the end of charging, making it difficult to reduce the size of the charging device. The price of the equipment increases.
(E) Device equipment equipped with batteries is rapidly becoming more complex and miniaturized due to diversification of applications and rapid progress of ICs. The battery and its ambient temperature rise rapidly due to the heat storage effect.
(F) Depending on the battery type, even if it is a normal charge (8-18h charge), the charge characteristics are significantly different (see Fig. 17), so it is easy to accurately predict and judge the end of charge. Therefore, there are many types of batteries in which it is difficult to implement quick charging and short-time charging.
(G) Conventionally, means for avoiding a sudden increase in battery voltage, battery temperature, and battery pressure generated during charging in constant current charging (especially rapid charging and short-time charging) has been proposed. Absent.
Under such circumstances, the correlation between the change in charge supply during charging by constant current charging and the reaction of the chemical system in the battery and the charging characteristics has been studied in detail, and depending on the change in charge supply during charging, the correlation is constant. It has been found in the present invention that the problem of current charging can be solved.

Next, an object of the charging method according to claims 1 to 6 and the charging device according to claims 7 and 8 will be described. However, since the charging method of claims 2 to 6 is a technical idea as an aspect included in the technical idea of the charging method of claim 1, it has the same purpose as the charging method of claim 1, and The individual objects of claims 2 to 6 are combined.
The present invention described in claim 1 typically has the following (1) to (9).
(1) Charging characteristics that are significantly different from normal constant current charging by periodically superimposing a pulse voltage on the charging voltage (for example, sudden sudden rises during charging during fast charging and short-time charging occur) It is an object to provide a charging method that has no charging characteristics.
(2) The pulse voltage is periodically superimposed on the charging voltage for constant current charging to maintain the advantages of constant current charging and prevent the disadvantages (especially the inevitable disadvantages) that occur in constant current charging. -To provide a charging method that can be avoided.
(3) Another object of the present invention is to provide a charging method that suppresses a rapid change in battery temperature, battery voltage, or battery pressure in rapid charging or short-time charging using constant current charging.
(4) An object of the present invention is to provide a charging method capable of shortening the charging time in rapid charging or short-time charging using constant current charging (that is, maintaining the charge supply method of constant current charging). .
(5) To provide a charging method that prevents or avoids a sudden rise in battery temperature during charging, which is unavoidable with conventional constant current charging, in rapid charging or short-time charging using constant current charging. Objective.
(6) To provide a charging method that prevents or avoids an abnormal rise in battery voltage and battery deterioration, which are inevitable with conventional constant current charging, in rapid charging or short-time charging using constant current charging. Also aimed.
(7) For quick charging or short-time charging using constant current charging, install a complicated control circuit to accurately determine battery / electrode modification and charging termination, which was inevitable with conventional constant current charging. The purpose is to make it unnecessary.
(8) The purpose is to expand the range of battery types that can be charged quickly and quickly.
(9) It is also intended to facilitate the miniaturization of a battery capable of rapid charging and short-time charging, and to suppress an increase in battery price.

Another object of the present invention of claim 2 is to enjoy the effect obtained by the generation of excitation energy emission in which a pulse voltage is accumulated in a coil.
Another object of the present invention of claim 3 is to enjoy the effect obtained when the coil that generates the pulse voltage forms a series resonance circuit.
Another object of the present invention of claim 4 is to enjoy the effect obtained when the capacitor of the series resonant circuit including the coil that generates the pulse voltage is the electrode of the secondary battery.
Another object of the present invention of claim 5 is to enjoy the effect obtained by causing the charging circuit to generate the synthesized pulse voltage.
Another object of the present invention of claim 6 is to enjoy an effect obtained by causing a charging circuit to generate a constant current of a charging voltage of constant current charging in which a pulse voltage is periodically superimposed.

An object of the present invention of claim 7 is to provide a charging device that facilitates the implementation of the charging method of the present invention of claims 1 to 3.
An object of the present invention of claim 8 is to provide a charging device that facilitates the implementation of the charging method of the present invention of claim 4.

The charging method according to claim 1 is characterized in that the pulsed voltage is periodically superimposed on the charging voltage for constant current charging and applied to the secondary battery.
The charging method of claim 2 is characterized in that the pulsed voltage of the charging method of claim 1 is generated by the release of excitation energy accumulated in the coil. The pulsed voltage of the charging method is generated by the release of excitation energy accumulated in the coil of the series resonance circuit.
In the charging method of claim 4, the pulse voltage of the charging method of claim 3 is generated by the release of excitation energy accumulated in a coil of a series resonance circuit having a capacitor as an electrode of a secondary battery to be charged, It is characterized by.
The present invention according to claim 5 is characterized in that the pulsed voltage of the charging method according to claim 1 is generated in the charging circuit by converting the analog information of the voltage waveform into digital information and using the digital information.
6. The charging method according to claim 6, wherein the charging circuit is provided with a detecting means for the charging current, and a pulse is generated by the waveform generator from information on the charging current detected by the detecting means and information on the pre-stored pulse voltage. A constant current in which a state voltage is periodically superimposed on a charging voltage is generated and supplied to a secondary battery.

The charging device according to claim 7, wherein the charging circuit having a constant current charging circuit means controls the supply of a direct current to the coil by accumulating excitation energy in the coil of the charging circuit and generating a pulsed voltage due to its discharge. With
The pulsed voltage generated by the DC current supply control by the control means is configured to be periodically superimposed on the charging voltage for constant current charging and applied to the secondary battery.
The charging device according to claim 8 is characterized in that the coil generating the pulse voltage of the charging device according to claim 7 is a coil of a series resonance circuit.

Next, effects of the charging method according to claims 1 to 6 and the charging device according to claims 7 and 8 will be described. However, since the charging method of claims 2 to 6 is a technical idea as an aspect included in the technical idea of the charging method of claim 1, it has the same effect as the charging method of claim 1, and , Have individual distinctive effects.
(A) According to the charging method described in claim 1, the following effects (1) to (9) are typically obtained.
(1) Although charging using constant current charging, charging characteristics that are significantly different from constant current charging (for example, prevention and disappearance of sudden sudden rise during charging in quick charge and short time charge) .
(2) Charge time is shortened in quick charge and short charge compared to normal constant current charge.
(3) In rapid charging and short-time charging, the sudden rise in battery temperature during charging, which was inevitable with conventional constant current charging, is prevented and avoided.
(4) Abnormal rise in battery voltage and battery deterioration during charging can be prevented and avoided during fast charging and short-time charging.
(5) For quick charging and short-time charging, it is not necessary to install a complicated control circuit for accurate determination of battery / electrode modification and charging completion, which is essential in the past.
(6) An effective known technique (for example, a charge termination technique) for normal constant current charging can be used.
(7) Conventionally, the opportunity of adopting rapid charging and short-time charging also extends to a battery of a type in which rapid charging and short-time charging are difficult.
(8) The effect of the invention can be improved by changing the setting of the pulse voltage.
(9) It is possible to reduce the size of the battery and the charging device in accordance with the trend of reducing the mounting space.

(B) According to the charging method of claim 2, since the generation of the pulsed voltage is due to the excitation energy release of the coil, it has the same effect as that of claim 1 and includes, for example, the following (i) to (iv) ) Etc. are obtained.
(I) Since the pulsed voltage generation can be controlled by controlling the excitation energy accumulation of the coil, the pulsed voltage can be precisely controlled by controlling the DC current supply time.
(Ii) Accumulation of the excitation energy of the coil is determined by the supply time of the direct current, and the supply time is completed in a short time of 1 / several hundreds (seconds).
(Iii) The charging circuit system can be greatly simplified.
(Iv) It has been found in the present invention that the pulsed voltage due to the excitation energy release has a great influence on the reaction system in the battery during charging.
(C) According to the charging method of claim 3, since the coil of the series resonance circuit is used to generate the pulse voltage, the charging method of claim 2 has the same effect as in claim 1. In addition to the specific effects, for example, a resonance voltage can be generated by a series resonance circuit, and a pulse voltage in which a rapidly rising voltage generated in excitation energy release and the resonance voltage are continuous can be obtained.
Further, it has been found in the present invention that a pulsed voltage including a resonance voltage is effective for enjoying the effect of the charging method of the present invention.
(D) According to the charging method of claim 4, since the electrode of the secondary battery to be charged is used as the capacitor of the series resonance circuit, the effect equivalent to that of claim 1 is obtained, and claim 2 In addition to the unique effects of (1) and (3), for example, a pulsed voltage including a resonance voltage with the secondary battery that changes as the charging progresses is superimposed on the charging voltage to further increase the effect of the pulsed voltage. Improve.
(E) According to the charging method of claim 5, even if it is a pulsed voltage generated in the charging circuit by digital information, the waveform of the original pulsed voltage can be accurately reproduced. An effect equivalent to 1 can be obtained.
(F) According to the charging method of claim 6, since the charging current itself superimposed with the pulsed voltage is reproduced by the detection information and the digital information technology, the same effect as in claim 1 can be achieved with a certain probability. It becomes possible to obtain.

(G) According to the charging device of claim 7, the charging method of claims 1 to 3 can be carried out easily and accurately.
(H) According to the charging device of claim 8, the charging method of claim 4 can be carried out easily and accurately.

Embodiments of the charging method according to claims 1 to 6 and the charging device according to claims 7 to 8 will be specifically described below.
Since the charging method of claims 2 to 6 is a technical idea as an aspect included in the technical idea of the charging method of claim 1, matters common to claim 1 are referred to in the description of claim 1. To do.
<Charging method of claim 1>:

The charging method according to claim 1, wherein the pulsed voltage is periodically superimposed on the charging voltage of the constant current charging and applied to the secondary battery, and the constant current is superimposed on the charging voltage of the pulsed voltage. The content of charging can be controlled in a suitable direction.

<Pulse voltage>:
Charge is supplied to the battery in a state where the pulse voltage is periodically superimposed on the charging voltage of constant current charging, and the effects of the invention specific to the charging method of claims 1 to 7 are enjoyed. The pulse voltage is not limited in its voltage waveform, but is effective in enjoying the effects of the invention because it is a locus in which the voltage waveform continuously moves in a positive potential region. The pulse voltage continuously moves in the positive potential region. First, the voltage always exists in the positive potential region, second, the voltage changes, and third, the voltage change continuously. It is to be.
Further, the term “pulse voltage” is used in the whole meaning from the generation to the end of the pulse voltage.
1 to 6 are exemplifications of preferred embodiments of the voltage waveform of the pulse voltage of claims 1 to 6.
FIG. 1 is an explanatory diagram of a voltage waveform of a pulsed voltage generated by releasing excitation energy of a coil, and is generated by the charging method according to claim 2. The pulse voltage in FIG. 1 falls slightly from the charging voltage for constant current charging (the level indicated by the symbol Vd indicated by the horizontal arrow), rises rapidly, reaches the peak voltage Vt, and then returns to the charging voltage level. ing. The horizontal line labeled OV at the bottom of FIG. 1 indicates the zero volt level. Note that the voltage waveform first rising slightly after falling from the level of the voltage Vd is due to the generation method of the pulse voltage.
The pulse voltage in FIG. 2 is an explanatory diagram of the voltage waveform of the pulse voltage in which a high voltage that rises high by excitation energy release and a resonance voltage continues, and can be generated by the charging method according to claims 3 and 4. .
In the pulse voltage shown in FIG. 2, a high voltage waveform is generated first, a resonance voltage is generated by resonance with the high voltage, the high voltage and the resonance voltage are continuous, and the resonance voltage is attenuated small. The voltage waveform is as follows. The pulse voltage in FIG. 2 corresponds to the resonance condition and a relatively large resonance voltage is generated.
The pulse voltage in FIG. 3 is an explanatory diagram of a voltage waveform in which a high voltage that rises upon excitation energy release and a weak resonance voltage are continuous. The pulse voltage in FIG. 3 is a case where a weak resonance voltage is generated between the coil and the parasitic capacitance of the circuit.
The pulse voltage in FIG. 4 is an explanatory diagram of a voltage waveform in which a high voltage that rises due to excitation energy release and a weak resonance voltage are continuous. FIG. 4 shows a case where a weak resonance voltage is generated.
The pulse voltage of FIG. 5 is a case where the voltage rising first is weak and the continuous resonance voltage is also weak. Even in such a case, the effect of the invention of the charging method of claims 1 to 6 can be enjoyed. It is valid.
The pulse voltage shown in FIG. 6 has a continuous voltage waveform and can be easily generated by the charging method according to claim 5.
<Duty ratio of pulse voltage>:

The duty ratio of the pulse voltage is the ratio (Tb / Td) between the time from the generation of the pulse voltage to the end (extinction) (Tb in FIG. 9) and the time of the pulse voltage overlap period (Td in FIG. 9) Then, the duty ratio (Tb / Td) is such that Tb is smaller than Td, and the effect of the charging method of the present invention can be increased. When the duty ratio (Tb / Td) is, for example, 1/50 to 1/3000 (preferably 1/80 to 1/2500, particularly preferably 1/100 to 1/2000), the charging of the present invention is performed. Enjoying the effect of the method becomes easier.
When the duty ratio (Tb / Td) is larger than 1/50, the effect appearing in the above-described battery is reduced, and even if the duty ratio (Tb / Td) is smaller than 1/3000, the effect appearing in the above-described battery is lowered.
<Generation of pulse voltage and periodic superposition>:

The pulse voltage can be generated by any method other than the above-described generation method as long as the effect of the charging method of the present invention can be enjoyed by periodic superposition of the constant current charging on the charging voltage.
“Periodic” of “periodically superimposing” the pulse voltage means that it is representative of a regular cycle (for example, a constant cycle), but may include a non-regular cycle. is doing. The charging voltage on which the pulse voltage is superimposed may be a charging voltage at a charging rate of fast charging, short-time charging, or normal charging as long as it is a constant current charging voltage.
Constant current charging is a method of supplying a direct current having a constant current value, called a constant current charging method, to a battery.
The control method for making a constant current value in constant current charging is arbitrary, and may be a known control method or a newly created control method.
<Characteristics of the charging method of claims 1 to 6>:

The characteristics of the charging method of claims 1 to 6 are, for example, the following (1) to (6) according to observation, measurement, and confirmation in the examination of the experiment subject.
(1) Charging efficiency and charging characteristics that do not occur in constant current charging (charging with DC current of a constant current value) occur.
(2) With conventional AC / intermittent charging, an accident occurred immediately when charging with a charging voltage exceeding the upper limit voltage of the battery. However, in the charging methods of claims 1 to 6, even if the peak voltage of the pulse voltage exceeds the upper limit voltage of the battery, it does not immediately lead to the occurrence of an accident.
(3) In conventional charging with alternating current and intermittent current, it was difficult to solve the unavoidable rise in battery voltage during charging.
(4) In conventional charging with alternating current and intermittent current, the dent light can be prevented from being generated by passing the current on / off and adopting a long off time. However, in the charging methods according to claims 1 to 6, the effect of preventing the generation of dent light was obtained by the periodic superposition of the pulse voltage.
(5) In constant current charging (especially rapid charging or short-time charging by constant current charging), it was difficult to prevent sudden increase in battery temperature during charging even if the conditions were changed. However, the charging methods of claims 1 to 6 can be prevented.
(6) In the charging method according to claims 1 to 6, charging at a higher charging rate and charging in a shorter time are possible than in the case of conventional quick charging.
<Charging method of claim 2>:

The charging method of claim 2 is an invention characterized in that the pulsed voltage of the charging method of claim 1 is generated by the release of excitation energy accumulated in the coil. FIG. 7 is an explanatory diagram showing an example of a charging circuit as an embodiment of the charging method according to claim 2. In FIG. 7, the charging circuit for constant current charging is a high-speed switch (for example, a MOSFET), which is provided with a coil as a circuit means so that a DC current from a power source can be turned on / off in a charging pulse control / output control circuit. ) A direct current of the power source is supplied to the coil when it is turned on for a short time (substantially, instantaneously). When the high-speed switch is turned off, the excitation energy accumulated in the coil is released to generate a pulsed voltage, which is superimposed on the charging voltage of the constant current (that is, constant DC current) supplied from the constant charging circuit to the battery. Charge.
The battery protection / charge control circuit can be a known control circuit used in a constant current charging circuit. As the diode, a diode (for example, a fast recovery diode and a Schottky barrier diode) having a high response speed suitable for passing a pulsed voltage is suitable.
The charge pulse control / output control circuit controls the accumulation of excitation energy by ON / OFF time control of the DC current supplied to the coil by the switch, and also controls the pulse voltage generated by the discharge. It also controls time control of the period in which the pulse voltage is superimposed.
<Charging method according to claims 3 and 4>:

The charging method according to claims 3 and 4 is a case where a coil of a series resonance circuit is used as the coil of the charging method according to claim 2 using a coil.
FIG. 8 is an explanatory diagram showing an example of a charging circuit as an embodiment of the charging method according to claims 3 and 4. In FIG. 8, the charging circuit is configured by a closed loop A in which a constant current for constant current charging is passed through a series resonant circuit, and a closed loop B in which a direct current for accumulating excitation energy is passed through a coil of the series resonant circuit, This is the same as FIG.
FIG. 9 is an explanatory diagram of the voltage waveform of the charging voltage on which the pulse voltage generated by the charging circuit of FIG. 8 is superimposed. The voltage waveform in FIG. 9 is observed and measured by connecting a signal waveform measuring device such as a synchroscope between the positive electrode side of the battery 14 and the ground.
In the following, the relationship between the function of the charging circuit and generation of the pulse voltage will be described based on the charging circuit of FIG. 8 and the voltage waveform explanatory diagram of FIG.

In the charging circuit of FIG. 8, the series resonance circuit 20 is configured by a series connection of a coil 12, a high-speed diode 13 for preventing backflow, and a battery 14 (using positive and negative electrodes as a capacitor of the series resonance circuit). When charging, the battery 1
4, a resonance voltage is generated, and a pulse voltage including electrode information is superimposed.
The switch 16 has a high speed (for example, 100 to 0.00001 μS (preferably 10 to 0.0001).
Any switch (eg, MOSFET) that can be turned on / off in μS)) can be used. Further, the charging voltage superimposed with the pulse voltage is applied to the battery 14 by making the time from the generation of the pulse voltage to the end (Tb in FIG. 9) faster than the control response time of the constant current circuit 15. At this time, it is desirable to reduce the influence of the control of the constant current circuit 15 on the pulse voltage. This is because the effect of the pulse voltage on the battery 14 (control effect on the electrical reaction) is increased by the relaxation. The mitigation of the effect means suppression of a voltage that has risen by a pulsed voltage under the control of the constant current circuit 15.

In the charging circuit 10, since the power source current of the power source 11 flows directly to the coil 12 of the series resonance circuit 20, the excitation energy can be accumulated in the coil 12 even in a short time.
Since the switch 16 controls the time from the generation to the end of the pulse voltage by the on / off control, it is desirable to make the on / off control time shorter than the control response time of the constant current circuit 15.
The diode 13 is suitably a diode (for example, a fast recovery diode or a Schottky barrier diode) having a high response speed suitable for passing a changing pulse voltage.
The constant current circuit 15 may be a known constant current circuit, a created constant current circuit, or a new constant current supply method (see FIG. 10) as long as a constant current (a constant direct current) can be controlled. Good. FIG. 10 is an explanatory diagram of an example of a new constant current supply method.

When the switch 16 is off, the charging circuit 10 is supplied with a constant current from the constant current circuit 15 in the closed loop A (flow indicated by an arrow A in FIG. 8) and charges the battery 14 with the series resonance circuit 20. The constant current charging time is the time indicated by the symbol Ta and its waveform in the voltage waveform of FIG.
When the time indicated by the symbol Ta ends, the switch 16 of the charging circuit 10 is switched from OFF to ON, the DC current of the power supply 11 flows in the closed loop B, and the excitation energy is accumulated in the coil 12 of the series resonance circuit 20. The on time of the switch 16 is extremely short (for example, 100 to 0.00001 μS). The on time of the switch 16 is the time indicated by the symbol Tc and its waveform in the voltage waveform of FIG. During the time period between T3 and T4, since the power source current flows in the closed loop B between the power source 11 and the coil 12, the constant current for constant current charging does not flow between the coil 12 and the battery 14. Because it becomes.
Next, immediately after the switch 16 is switched from on to off for a very short time (substantially instantaneously), the excitation energy accumulated in the coil 12 is released and the first rise of the pulse voltage is started. Voltage is generated. In the voltage waveform of FIG. 9, the first rising voltage of the pulse voltage is generated at time T4, and at the same time, a constant current for constant current charging flows. Then, since the off time of the switch 16 continues, the generated pulse voltage is superimposed on the constant current charging voltage.
When the first rising voltage generated by the excitation energy release satisfies the resonance condition, the resonance voltage is generated and becomes a pulsed voltage having a voltage waveform in which the first rising voltage and the resonance voltage are continuous. . In the voltage waveform of FIG. 9, a pulsed voltage is generated at time T4, and the pulsed voltage ends at time T1. The pulse voltage has a voltage waveform having a time of Tb.
When the pulse voltage ends at the time point T1, the constant current charging is performed over the time indicated by the symbol Ta. And charging is performed by repeating these.

Regarding the charging method according to claims 3 and 4, several characteristics are observed, measured and confirmed. For example, it is the following features (1) to (7).
(1) Since the pulse voltage is affected by the coil 12 and a “deviation” occurs between the voltage and the maximum value of the current, the burden on the battery is reduced to maximize the amount of current in the battery 14. It becomes possible to supply.
(2) When the electrode state during charging is reflected in the resonance waveform, the effect of the invention (for example, charging efficiency, charging characteristics and charging speed) has been observed.
(3) In the observation by the signal waveform measuring apparatus, the amount of charge supplied to the battery 14 is increased by the pulse voltage.
(4) When there is a time difference between the control response time of the constant current circuit 15 and the duration of the pulse voltage, it has been observed that the amount of charge supplied to the battery 14 at the pulse voltage increases.
(5) It is possible to provide a direct current power source dedicated to direct current supplied to the coil 12. If it is a dedicated DC power supply, it is possible to increase the power supply voltage and increase the level of excitation energy accumulation, thereby further improving the effect of the second aspect of the present invention.
(6) It is possible to easily generate a resonance voltage by changing the conditions of the coil or / and the capacitor.
(7) Even if it is a pulse voltage including a resonance voltage with the stray capacitance, the effect of the invention can be enjoyed.
<Charging method of claim 5>:

The charging method according to claim 5 is a case where the analog information of the voltage waveform is converted into digital information and a pulse voltage is generated in the charging circuit by control based on the digital information.
For example, a switching control circuit, a waveform generator, and a DSP can be used, and other methods can be used.
<Generation of pulse voltage by switching control circuit>:
The method using the switching control circuit, for example, sends the waveform information of the transmitter containing the basic information of the voltage waveform of the pulsed voltage to the counter, where the waveform is sorted and the selected waveform information is switched. It is sent to the time generating code converter, and the conversion information (digital information) is sent to the driver, and the driver operates, for example, the switch in FIG. 7 or FIG. 8 to generate a pulse voltage in the charging circuit. FIG. 10 is a circuit diagram for generating a pulse voltage using the switching control circuit.
<Generation of pulse voltage by waveform generator>:
The waveform generator is a device that can create an arbitrary waveform element that is a component of the waveform and an arbitrary waveform from the waveform element creation. Commercially available waveform generators can be used by a plurality of device manufacturers (for example, Yokogawa Electric Corporation). In the generation of pulse voltage by the waveform generator, an analog pulse voltage voltage waveform is prepared in advance, converted into digital information by the waveform generator, and the driver of the charging circuit is operated by the driver using the converted information. To generate a pulse voltage in the charging circuit.
<Generation of pulse voltage by DSP>:
DSP (Digital Signal
Procesor) is a dedicated processor for performing digital arithmetic processing such as digital arithmetic on digital data with high speed and high accuracy to generate different modeling data, and is commercially available from a plurality of apparatus manufacturers. Even when using DSP, a voltage waveform of analog pulse voltage is prepared in advance and converted to digital information, and a pulse voltage is generated in the charging circuit by operating the switch of the charging circuit by the driver according to the conversion information. Let
<Charging method of claim 6>:

The charging method according to claim 6 is, for example, a method of outputting the entire constant current in which the pulse voltage is periodically superimposed on the charging voltage to the charging circuit by the function of the waveform generator or the DSP.
FIG. 11 is an explanatory diagram of the charging method of claim 6, comprising a charging current detection means for the charging circuit, and detecting the charging current (constant current) information of the charging circuit by the detection sensor, The digital information of the pulsed voltage is created from the information of the pulsed voltage to be generated by a waveform generator or DSP, and the performance is enhanced by the amplifier, which is output to the charging circuit for charging the battery.
<Charging device of claim 7>:

The charging device of claim 7 is an invention in which the technical idea of claim 2 is grasped from the viewpoint of the charging device.
FIG. 7 is also an explanatory view showing the contents of the charging device of claim 7. In the charging device according to claim 7, the charging circuit includes constant current charging circuit means and direct current control means supplied to the coil, and excitation energy accumulation in the coil is controlled by controlling the supplied direct current. It is characterized in that generation of a pulsed voltage due to the emission is controlled.
Therefore, the circuit configuration can be simplified, the energy storage control can be easily and accurately controlled, and the pulse voltage generation control can be easily and accurately controlled. Further, the effect of the invention that is produced by the charging method of FIG. 7 is also enjoyed as the effect of the invention for the charging device of claim 7.
<Charging device of claim 8>:
FIG. 8 is also an explanatory view showing the contents of the charging device of claim 8. The charging device according to claim 8 is configured such that the circuit means for constant current charging includes a series resonant circuit, and the pulsed voltage is generated in a coil of the series resonant circuit, whereby the pulsed voltage generates the resonant voltage. It can be included.
In addition, the charging device according to claim 8 has a structure in which constant current charging that overcomes the inherent drawbacks is simple, and a charging device that can also perform quick charging with simple and accurate control is obtained. Further, the effect of the invention produced by the charging method of FIG. 8 is enjoyed as the effect of the invention also for the charging device of claim 8.
<Subject of the charging method of the present invention>:

The battery to be charged by the charging method and the charging device according to the present invention may be any of ordinary charging, quick charging, and short-time charging methods, and there is no restriction on the type of battery, and in the past Even if the battery cannot perform the quick charge / short-time charge, it can be a battery capable of rapid charge / short-time charge if the present invention of claims 1 to 8 can be implemented.
In addition, the battery is an object to be charged in the present invention regardless of practical use or non-practical use. Furthermore, it becomes the charge object in this invention irrespective of the versatility and non-generality of a battery. General-purpose batteries include, for example, nickel / cadmium batteries (especially sealed), nickel / hydrogen batteries (especially sealed), lithium ion batteries, nickel / zinc, silver oxide / zinc batteries, and redox flow batteries. In any case, the charging is subject to the present invention.

In the present invention, it is in accordance with the object of the present invention, and any modification or partial change and addition is optional as long as the effects of the present invention are not particularly impaired. It is. EXAMPLES Next, although this invention is demonstrated concretely based on an Example, an Example is an illustration and does not restrain this invention.

The nickel metal hydride battery was discharged at a constant current and used for an experimental battery. In Examples 1 and 2, a charging current in which a pulsed voltage is periodically superimposed on a DC current of constant current charging is passed through the battery, and the action on the in-battery reaction system in which the pulsed voltage proceeds by the DC current of constant current charging. The effect was observed from the charging characteristics, which is a projection of changes in the reaction system in the battery.
In Comparative Examples 1 and 2, only the DC current of constant current charging in Examples 1 and 2 was allowed to flow through the battery, and the effect of the pulse voltage in Examples 1 and 2 was confirmed.
In Example 1 and Comparative Example 1, the direct current for constant current charging was set to a condition in which a charging rate near full charging was achieved in a very short rapid time. In Example 2 and Comparative Example 2, the direct current for constant current charging was set to a condition where the charging rate was in the vicinity of complete charging within a rapid time range.
<Example 1>

Nickel metal hydride battery (GP110AAAHC made by GPI, capacity 1100
6 were connected in series with a charging circuit shown in FIG. 6, and the charging characteristics were measured. The battery used here was discharged at a constant current of 1A before the start of charging, the battery voltage was set to 1V, and the charging was started. The end of charging was the time when -ΔV5mV was detected.
A 12V power source was used as the charging power source, and the constant current circuit was controlled so that the charging current was 3.7A. The inductor used in the circuit was 100 microhenry, switching was 39 kHz cycle, and the duty ratio was 1/256. Further, the battery after charging was discharged at a constant current of 1 A, the discharge time was measured, the amount of discharge was calculated, and the charging rate was obtained.
According to Table 1 showing the results, the battery temperature increased by 17.1 ° C. in about 10 minutes. However, in the case of Comparative Example 1, only the direct current with the same constant current charge as in Example 1 was passed under the same conditions as in Example 1, and the battery temperature increased by 30 ° C. (see Table 3).

<Example 2>

The constant current circuit was controlled to make the constant current charging DC current 1A. Under the same conditions as in Example 1, the pulse voltage was superimposed on the constant current charging DC current to form a charging current. Charging characteristics were determined within the general quick charging range. According to Table 2 showing the results, the battery temperature increased by 10.5 ° C. during the general quick charge time. However, in the case of Comparative Example 2, only the same constant current charging direct current as in Example 2 was passed under the same conditions as in Example 2 and the battery temperature increased by 10.5 ° C. (see Table 4).

<Comparative Example 1>

The same charging circuit shown in FIG. 6 as in Example 1 was used, and the constant current circuit was used to control the direct current to 3.7 A as in Example 1. Without using the switching control circuit, the battery was charged with a direct current of 3.7 A from the constant current circuit. The results are shown in Table 3.

<Comparative Example 2>

The same charging circuit shown in FIG. 6 as in Examples 1 and 2 was used, and the direct current from the constant current circuit was controlled to 1 A as in Example 2. Without using a switching control circuit, the battery was charged by passing a direct current 1A from a constant current circuit through the battery. The results are shown in Table 4.

  The charging method and the charging device according to the present invention enable charging at a charging characteristic and a charging speed that cannot be generated by the conventional constant current charging, although the charging method is based on constant current charging. Improves sex.

It is explanatory drawing of the embodiment of the voltage waveform of a pulse-form voltage. It is explanatory drawing of the other embodiment of the voltage waveform of a pulse-form voltage. It is explanatory drawing of the other embodiment of the voltage waveform of a pulse-form voltage. It is explanatory drawing of the other embodiment of the voltage waveform of a pulse-form voltage. It is explanatory drawing of the other embodiment of the voltage waveform of a pulse-form voltage. It is explanatory drawing of the other embodiment of the voltage waveform of a pulse-form voltage. FIG. 3 is an explanatory diagram of a charging circuit of the charging method according to claim 2. FIG. 6 is an explanatory diagram of a charging circuit of the charging method according to claim 4. FIG. 5 is an explanatory diagram of a voltage waveform of a charging voltage on which the pulse voltage of claim 4 is superimposed. FIG. 3 is a circuit diagram for generating a pulse voltage by a switching control circuit. 7 is an explanatory diagram of a charging method according to claim 6. FIG. It is explanatory drawing which shows the charge characteristic of constant current charge typically. It is explanatory drawing which shows the charge characteristic of constant voltage charge typically. It is explanatory drawing which shows typically the charge characteristic in the case of carrying out rapid charge of a sealed lead battery by constant voltage charge. It is explanatory drawing which shows the charge characteristic by constant current charge (20 degreeC) of the battery of a different type. It is explanatory drawing which shows the charge characteristic at the time of carrying out constant current charge of the sealed nickel cadmium battery by different charging rates. It is explanatory drawing which shows the relationship between the battery ambient temperature and battery life in charging / discharging of a sealed nickel cadmium battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Charging circuit 11 DC power supply 12 Coil 13 High-speed type diode 14 Battery 15 Constant current circuit 16 Switch 20 Series resonance circuit

Claims (13)

A method for charging a secondary battery, characterized in that a pulsed voltage is periodically superimposed on a charging voltage for constant current charging and applied to the secondary battery. A charging method for a secondary battery, characterized in that a pulsed voltage generated by releasing the excitation energy accumulated in the coil is periodically superimposed on the charging voltage for constant current charging and applied to the secondary battery. . A secondary battery characterized in that a pulsed voltage generated by releasing excitation energy accumulated in a coil of a series resonance circuit is periodically superimposed on a charging voltage of constant current charging and applied to the secondary battery. Charging method. The pulsed voltage generated by the release of excitation energy stored in the coil of the series resonance circuit using the electrode of the secondary battery to be charged as a capacitor is periodically superimposed on the charging voltage for constant current charging and applied to the secondary battery. A method for charging a secondary battery. The analog information of the voltage waveform is converted into digital information, and the pulse voltage generated by the charging circuit based on the digital information is periodically superimposed on the charging voltage for constant current charging and applied to the secondary battery. Rechargeable battery charging method. A charging current detecting means is provided in the charging circuit, and the pulsed voltage is periodically superimposed on the charging voltage by a waveform generator from information on the charging current detected by the detecting means and information on the pulsed voltage built in in advance. A method for charging a secondary battery, comprising generating a constant current and supplying the constant current to the secondary battery. A charging circuit having circuit means for constant current charging comprises control means for controlling the accumulation of excitation energy in the coil of the charging circuit and generation of a pulsed voltage due to its discharge by supplying a direct current to the coil,
A secondary voltage characterized in that a pulse voltage generated by supply control of the direct current by the control means is applied to a secondary battery by periodically superimposing it on a charging voltage of constant current charging. Battery charger. A charging circuit having circuit means for charging at a constant current through a series resonance circuit includes control means for controlling the accumulation of excitation energy in the coil of the series resonance circuit and generation of a pulsed voltage due to the discharge by supplying a direct current to the coil. And
A pulse voltage generated by controlling the supply of direct current to the coil by the control means is configured to be periodically superimposed on a charging voltage of constant current charging and applied to the secondary battery. Secondary battery charger. 9. The secondary battery charging device according to claim 8, wherein the series resonant circuit uses a secondary battery electrode to be charged as a capacitor. 7. The pulse-like voltage has a locus of a voltage waveform of a positive potential, and has at least a voltage waveform that rises to a voltage higher than the charging voltage to be superimposed. Charge method of the secondary battery as described in 2. 7. The method for charging a secondary battery according to claim 1, wherein the secondary battery to be charged is a secondary battery capable of rapid charging or short-time charging. 7. The secondary battery according to claim 1, wherein the secondary battery to be charged is a nickel / cadmium battery, a nickel / hydrogen battery, a lithium ion battery, nickel / iron, or a redox flow battery. How to charge the next battery. The secondary battery according to any one of claims 1 to 6, wherein the secondary battery to be charged is a single secondary battery or a combination battery of a plurality of single secondary batteries. Charging method.