JP6528585B2 - Non-aqueous secondary battery charging method and charging control device - Google Patents

Description

  The present invention relates to a non-aqueous secondary battery charging method and a charge control device.

  The charge control device for charging the non-aqueous secondary battery charges the non-aqueous secondary battery by supplying a current to the non-aqueous secondary battery.

  The non-aqueous secondary battery includes an electrolytic solution in which an electrolyte is dissolved in an organic solvent. For this reason, when the non-aqueous secondary battery is charged at high temperature when it is at high temperature, in addition to the reversible reaction of the normal battery, there is a concern that a side reaction causing decomposition of the electrolytic solution may occur. In particular, in the case of a secondary battery using a Si-based material as a negative electrode active material, the electrode is affected by the hysteresis due to charge and discharge to increase the polarization, so there is a concern about the decomposition of the electrolytic solution. The decomposition of the electrolytic solution may cause surface deterioration of the electrolytic solution and the electrode material, displacement of the potential of the positive electrode and the negative electrode, and a decrease in life, which may lower the charge / discharge cycle characteristics of the non-aqueous secondary battery.

  Then, the method of controlling an electric current according to temperature is proposed at patent document 1-8 when charging a non-aqueous secondary battery.

WO 2014/104280 JP, 2012-10593, A Unexamined-Japanese-Patent No. 2010-277839 JP, 2013-149609, A WO 2012/081423 JP-A-8-205418 JP-A-2-119539 JP, 2012-16109, A

  The inventor of the present application has keenly searched for a new charging method and charge control device different from the above-mentioned patent documents in order to suppress the decomposition of the electrolytic solution during charging of the non-aqueous secondary battery and improve the battery life.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a non-aqueous secondary battery charging method and a charge control device capable of improving the battery life.

The charging method of the non-aqueous secondary battery of the present invention is a charging method of charging the non-aqueous secondary battery and setting the net voltage of the non-aqueous secondary battery as a target voltage,
A temperature determination step of determining whether the temperature of the non-aqueous secondary battery before charging is equal to or higher than a predetermined value;
When it is determined in the temperature determining step that the temperature of the non-aqueous secondary battery is equal to or higher than a predetermined value,
i) an intermittent charging step of alternately repeating a charge-pause unit comprising a charging step of charging the non-aqueous secondary battery to the target voltage and a pausing step of pausing the charging temporarily, or ii) the non-aqueous secondary battery And an overshoot charging step of charging to an excess voltage exceeding the target voltage.

The charge control device according to the present invention controls the current supplied to the non-aqueous secondary battery by charging the non-aqueous secondary battery and setting the net voltage of the non-aqueous secondary battery as a target voltage. Equipped
The control unit
A temperature determination unit that determines whether the temperature of the non-aqueous secondary battery before charging is equal to or higher than a predetermined value;
An intermittent charging unit that alternately repeats a charge-pause unit consisting of a charging step of charging the non-aqueous secondary battery to the target voltage and a pausing step of pausing the charging temporarily;
An overshoot charging unit for charging the non-aqueous secondary battery to an excess voltage exceeding the target voltage;
Providing a selection unit for selecting one of the intermittent charging unit and the overshoot charging unit when the temperature judgment unit judges that the temperature of the non-aqueous secondary battery is equal to or higher than a predetermined value. It features.

  According to the above configuration, when it is determined that the temperature of the non-aqueous secondary battery is equal to or higher than the predetermined value, the intermittent charging process or the overshoot charging process is performed. In the intermittent charging step, the charging depth of the positive electrode and the negative electrode is deepened by performing the pausing step after the charging step at a constant current. Thereby, it is possible to suppress the decomposition of the electrolytic solution due to the overvoltage while achieving the polarization elimination in the electrode active material. Further, the heat generated by the charging can be released to the outside during the pausing of the pausing process, and the temperature increase of the battery can be suppressed. In the overshoot charge process, the non-aqueous secondary battery is charged to an excess voltage exceeding the target voltage. When the non-aqueous secondary battery is exposed to an excess voltage higher than the target voltage, the battery reaction proceeds positively, and the net voltage of the non-aqueous secondary battery can be made the target voltage in a short time. It takes less time to expose the non-aqueous secondary battery to high temperatures and high voltages, so that decomposition of the electrolytic solution can be suppressed, and a decrease in battery capacity due to deterioration of the electrolytic solution can be suppressed.

  Since the present invention has the above configuration, it is possible to provide a non-aqueous secondary battery charging method and a charge control device capable of improving the battery life.

It is an explanatory view of a charge control device of an embodiment of the present invention. It is a flowchart which shows the charge method of this embodiment. FIG. 6 is a diagram showing a voltage change with the passage of time at the time of charging in Test 1; FIG. 7 is a graph showing a voltage change with the passage of time at the time of charging in Test 2; FIG. 10 is a diagram showing a voltage change with the passage of time at the time of charging in Test 3; It is a graph which shows the voltage change accompanying time progress at the time of charge of the tests 1-5.

  A charge control device and a charge method of a non-aqueous secondary battery according to an embodiment of the present invention will be described.

  The charge control device 1 of the present embodiment controls the current supplied to the non-aqueous secondary battery 5 when charging the non-aqueous secondary battery 5, as shown in FIG. The charge control device 1 is used to charge the non-aqueous secondary battery 5 mounted on the vehicle 50. Any vehicle may be used as long as it uses electric energy from batteries for all or part of the power source. For example, electric vehicles, hybrid vehicles, plug-in hybrid vehicles, hybrid railway vehicles, electric forklifts, electric wheelchairs, electric assists There are bicycles and electric motorcycles.

  The charge control device 1 is a device that charges the non-aqueous secondary battery 5 and sets the net voltage of the non-aqueous secondary battery 5 to the target voltage Vp. The "net voltage" refers to the voltage of the non-aqueous secondary battery when the influence of the internal resistance of the non-aqueous secondary battery 5 is minimized and the voltage is uniform across the entire electrode active material. The “target voltage Vp” may be the voltage of the non-aqueous secondary battery 5 when the charge rate is 100%, or a non-aqueous system with a charge rate smaller than that (for example, 70%, 80%, 90%) It may be the voltage of the secondary battery 5. The target voltage Vp may be set to the maximum voltage that can be used without causing the performance deterioration of the non-aqueous secondary battery 5 or less. In the present embodiment, the voltage 4.2 V of the non-aqueous secondary battery 5 with a charging rate of 100% is set as the target voltage Vp. The minimum voltage of the non-aqueous secondary battery 5 was 3.0V.

  Each non-aqueous secondary battery 5 is a lithium ion secondary battery, and includes a negative electrode, a positive electrode, a separator, and a non-aqueous electrolytic solution. The negative electrode includes a current collector and an active material layer that covers the surface of the current collector and has a negative electrode active material. The positive electrode includes a current collector and an active material layer that covers the surface of the current collector and has a positive electrode active material.

  Examples of the positive electrode active material include a lithium-nickel-cobalt-manganese composite oxide, a lithium-manganese composite oxide having a spinel structure, a lithium iron phosphate compound, sulfur and the like. Moreover, as a negative electrode active material, Si-type materials, such as SiO, crystalline silicon, a silicon material, and carbon materials, such as graphite, are mentioned.

As one embodiment of the above silicon material, a layered silicon compound mainly composed of a polysilane from which CaSi is removed by reacting CaSi ₂ with an acid is synthesized, and the layered silicon compound is heated at 300 ° C. or higher to release hydrogen. Mention may be made of silicon materials produced by the method. The silicon material has a structure in which a plurality of plate-like silicon bodies are stacked in the thickness direction. This structure can be confirmed by observation with a scanning electron microscope or the like. Considering using the silicon material as an active material of a lithium ion secondary battery, the plate-like silicon body has a thickness in the range of 10 nm to 100 nm for efficient insertion and desorption reaction of lithium ions. Among them, those in the range of 20 nm to 50 nm are more preferable. The length of the plate-like silicon body in the long axis direction is preferably in the range of 0.1 μm to 50 μm. The plate-like silicon body preferably has a (longitudinal direction length) / (thickness) in a range of 2 to 1000.

  The silicon material preferably includes amorphous silicon and / or silicon crystallites. The size of the silicon crystallite is preferably in the range of 0.5 nm to 300 nm, more preferably in the range of 1 nm to 100 nm, still more preferably in the range of 1 nm to 50 nm, and particularly preferably in the range of 1 nm to 10 nm. The size of the silicon crystallite is calculated from X-ray diffraction measurement (XRD measurement) on the silicon material, and from the Scheller equation using the half width of the diffraction peak of the Si (111) plane of the obtained XRD chart. Be done.

  As a preferable particle size distribution of a silicon material when it measures with a general laser diffraction type particle size distribution measuring apparatus, it can illustrate that an average particle diameter (D50) exists in the range of 1-30 micrometers, More preferably, it is an average particle It can be exemplified that the diameter (D50) is in the range of 1 to 10 μm.

  The non-aqueous electrolyte contains a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent.

  Examples of non-aqueous solvents include cyclic esters, linear esters, and ethers. Examples of cyclic esters include ethylene carbonate, propylene carbonate, butylene carbonate, gamma butyrolactone, vinylene carbonate, 2-methyl-gamma butyrolactone, acetyl-gamma butyrolactone and gamma valerolactone. Examples of chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, methyl ethyl carbonate, propionic acid alkyl ester, malonic acid dialkyl ester and acetic acid alkyl ester. As ethers, for example, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane can be mentioned. As the non-aqueous solvent, a compound in which part or all of hydrogens in the chemical structure of the specific non-aqueous solvent is substituted with fluorine may be adopted. Examples of compounds in which part or all of the hydrogen in the chemical structure of the non-aqueous solvent is fluorine-substituted include fluoroethylene carbonate and difluoroethylene carbonate.

Further, as the electrolyte to be dissolved in the non-aqueous electrolytic solution, for example, lithium salts such as LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ can be used.

As a non-aqueous electrolytic solution, for example, 0.5 mol / l to 0.5 mol / l of lithium salt such as LiClO ₄ , LiPF ₆ , LiBF ₄ or LiCF ₃ SO _{3 in} a solvent such as ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate. A solution dissolved at a concentration of about 7 mol / l can be used.

  A separator is used as needed. The separator separates the positive electrode and the negative electrode and holds the non-aqueous electrolyte, and is a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), polypropylene, polyethylene terephthalate (PET), methyl cellulose Etc. are exemplified.

  As shown in FIG. 1, the charge control device 1 is provided between the power supply 6 and the non-aqueous secondary battery 5, and controls the current supplied from the power supply 6 to the non-aqueous secondary battery 5. . The power supply 6 outputs electric power to charge the non-aqueous secondary battery 5, and may be, for example, an AC power supply, or may convert the AC power into a DC power and output it. Good.

  The charge control device 1 includes a control unit 2 and an operation unit 3.

  The control unit 2 mainly includes a computer, and a temperature determination unit 21, a time determination unit 22, a current detection unit 23, a constant current constant voltage charging unit 24, an intermittent charging unit 25, and an overshoot charging unit And a selection unit 27.

  The vehicle 50 is provided with a temperature sensor 51 that measures the temperature Tx of the non-aqueous secondary battery 5. The temperature sensor 51 is, for example, a thermistor. The temperature determination unit 21 determines whether the temperature Tx of the non-aqueous secondary battery 5 is equal to or higher than a predetermined value To based on the battery temperature signal emitted from the temperature sensor 51 of the vehicle 50. The predetermined value To is, for example, the lower limit value of the temperature at which the electrolyte solution of the non-aqueous secondary battery 5 may be decomposed. The predetermined value To is preferably a specific temperature in the range of 35 to 55 ° C., and more preferably 40 to 50 ° C. In the present embodiment, the predetermined value To is 45 ° C.

  Time determination unit 22 determines whether or not charge allowable time Ha that can be spent for charging non-aqueous secondary battery 5 is equal to or longer than reference charge time Ho. The reference charging time Ho is a time required to increase the net voltage of the non-aqueous secondary battery 5 to the target voltage Vp as described later.

  The charge allowable time Ha is arbitrarily set by the operator operating the charge control device 1. For example, the time determination unit 22 is connected to the quick charge switch 32 provided in the operation unit 3. When the operator operates the quick charge switch 32, the time determination unit 22 determines that the charge allowable time Ha is less than the reference charge time Ho. When quick charge switch 32 is not operated, time determination unit 22 determines that charge allowable time Ha is equal to or longer than reference charge time Ho.

  The current detection unit 23 detects a current signal transmitted from the current measuring device 52 mounted on the vehicle 50. The current signal has information on the voltage and current value of the non-aqueous secondary battery 5 measured by the current measuring device 52. The constant current constant voltage charging unit 24, the intermittent charging unit 25 and the overshoot charging unit 26 of the control unit 2 are configured to supply the current supplied to the non-aqueous secondary battery 5 based on the current signal transmitted from the current detection unit 23. Control.

  The constant current constant voltage charging unit 24 performs a constant current constant voltage charging process. In the constant current constant voltage charging step, the non-aqueous secondary battery 5 is charged to a target voltage Vp with a constant current, and further charged so as to maintain the target voltage Vp after the non-aqueous secondary battery 5 reaches the target voltage Vp. .

  In the constant current constant voltage charging step, the non-aqueous secondary battery 5 is exposed to the target voltage Vp for a predetermined time after reaching the target voltage Vp. Immediately after the non-aqueous secondary battery 5 reaches the target voltage Vp, both the positive and negative electrodes have a shallow charging depth. That is, immediately after the non-aqueous secondary battery 5 reaches the target voltage Vp, in the positive electrode active material, Li ions are exclusively released from the surface, and the amount of internal Li ions released is small. Li ions are unevenly distributed on the surface of the negative electrode active material, and the lithium ions are not diffused to the inside of the negative electrode active material. Although the target voltage Vp is reached exclusively between the surfaces of the positive electrode active material and the negative electrode active material, the target voltage Vp is not reached between the inside of the positive electrode active material and the negative electrode active material. When a relatively large current flows in the non-aqueous secondary battery 5, the target voltage Vp immediately after reaching the target voltage Vp is largely affected by the internal resistance of the battery.

  Therefore, in the present embodiment, after reaching the target voltage Vp, the current is gradually decreased so that the non-aqueous secondary battery 5 maintains the target voltage Vp, and charging is continued until the net voltage reaches the target voltage. Do. As a result, the voltage between not only the surface of the positive electrode and the negative electrode active material but also the voltage between the positive electrode and the negative electrode can reach the target voltage Vp. In the lost state, the battery net voltage, that is, the net voltage can reach the target voltage Vp.

  In the constant current constant voltage charging step, the positive electrode maintains a high potential while maintaining the target voltage Vp. For this reason, the electrolytic solution in the vicinity of the positive electrode is exposed to the oxidation state. However, since the temperature Tx of the non-aqueous secondary battery 5 is less than the predetermined value To, decomposition of the electrolytic solution is unlikely to occur. Therefore, when the temperature Tx of the non-aqueous secondary battery 5 is less than the predetermined value To, even if constant current constant voltage charging is performed in which a relatively high current is flowed at a constant current and constant voltage, decomposition of the electrolyte is It is hard to occur and can exhibit excellent cycle characteristics. If the temperature Tx of the non-aqueous secondary battery 5 is less than the predetermined value To, constant current charging or constant voltage charging is performed instead of constant current constant voltage charging performed in the constant current constant voltage charging step described above. It is also possible. In constant current constant voltage charging, constant current charging and constant voltage charging, constant current constant voltage charging can be performed in a short time when charging is performed with a current of the same current value.

  In the constant current constant voltage charging step, the target voltage Vp is maintained by gradually reducing the current value after reaching the target voltage Vp to maintain the target voltage Vp, but the end current value is 0.3 C rate or less, further 0.2 C rate or less The target voltage Vp may be maintained until the 0.15 C rate or less and the 0.1 C rate or less. The 1 C rate means a current value required to completely charge or completely discharge the battery in one hour at a constant current.

  The intermittent charging unit 25 performs an intermittent charging process. In the intermittent charging step, a charge-pause unit consisting of a charging step of charging the non-aqueous secondary battery 5 to the target voltage Vp and a pausing step of pausing charging is alternately repeated. In general, when the target voltage Vp is continuously applied to the non-aqueous secondary battery 5 for a long time, the positive electrode maintains an oxidation state, and decomposition of the electrolyte proceeds particularly in the vicinity of the positive electrode. Therefore, in the intermittent charging step, by performing the pausing step after the charging step at a constant current, it is possible to suppress the decomposition of the electrolyte solution due to the overvoltage while promoting the diffusion of Li into the inside of the positive electrode active material. In addition, during the pausing step, the heat generated in the charging step can be released to the outside, and the decomposition reaction of the electrolytic solution can be suppressed.

  In the intermittent charging step, the current value of the charging in the charging step of the charging-pause unit may be smaller than the current value of the charging in the charging step of the immediately previous charging-pause unit. As a result, it is possible to increase the charge depth to a later charge-pause unit and uniformly bring the entire battery to the target voltage Vp. Moreover, the voltage error due to the internal resistance of the battery can be suppressed. Therefore, the net voltage of the battery can be brought close to the target voltage Vp.

  Immediately after the charging step, Li ions are exclusively released from the surface of the positive electrode active material, and the amount of Li ions released inside is small. Li ions are unevenly distributed on the surface of the negative electrode active material, and the lithium ions are not diffused to the inside of the negative electrode active material. In particular, the Si-based negative electrode active material has large expansion and contraction due to charge and discharge, and Li ions are unevenly distributed on the surface of the negative electrode active material, and the hysteresis of the charge and discharge curve is large. Therefore, in the present embodiment, by performing the pausing step after the charging step, the hysteresis of the charge and discharge curve can be eliminated, Li can be diffused in the entire negative electrode active material, and the entire battery can be made to have a uniform voltage.

  In the pause process of the intermittent charge process, the charge control device 1 is temporarily connected to the non-aqueous secondary battery 5 and the charge is suspended by stopping the power supply.

  It is preferable to suspend charging until the non-aqueous secondary battery 5 becomes lower than the target voltage Vp in the charging-stop unit stopping step in the intermittent charging step. Thereby, the applied voltage can be uniformly spread over the entire electrode active material, and the charging depth can be deepened.

  In the intermittent charge process, the charge-pause unit is repeated until the net voltage of the non-aqueous secondary battery reaches the target voltage Vp. Furthermore, the repetition of the charge-pause unit is preferably ended when the voltage of the non-aqueous secondary battery 5 at the end of the pause step maintains a voltage close to the target voltage Vp. For example, in the intermittent charging step, the voltage of the non-aqueous secondary battery 5 at the end of the pause step, that is, the voltage detected by the current detector 23 is 90% or more, and further 95% or more, 97% or more of the target voltage Vp. It is good to end the charge-pause unit repetition when maintaining 99% or more.

  In the present embodiment, the current value supplied to the non-aqueous secondary battery 5 in the first charging-pause unit charging step is a 1 C rate. The current value in the charge step of each cycle of charge-rest unit is set to 1/3 of the current value of the charge step of the previous charge-rest step. The rest step in the charge-rest unit of each cycle was one hour.

  The overshoot charge unit 26 performs an overshoot charge process. The overshoot charge process charges the non-aqueous secondary battery 5 to the excess voltage Vq exceeding the target voltage Vp. The excess voltage Vq is higher than the target voltage Vp exposed to the non-aqueous secondary battery 5 in the intermittent charging step and the constant current constant voltage charging step. When charged to the excess voltage Vq, the charging rate of the non-aqueous secondary battery 5 may be a desired charging rate. When the non-aqueous secondary battery 5 is exposed to the excess voltage Vq higher than the target voltage Vp, immediately after the excess voltage Vq is reached, there is a difference between the voltage between the surface of the positive electrode active material and the surface of the negative electrode active material However, after reaching the excess voltage Vq for a while, Li ions move in the positive electrode active material and the negative electrode active material, and the whole of the positive electrode active material and the negative electrode active material becomes the target voltage Vp. According to the overshoot charge process, the battery reaction proceeds positively, and the net voltage of the non-aqueous secondary battery can be made the target voltage Vp in a short time. The time for exposing the non-aqueous secondary battery 5 to high temperature and high voltage can be reduced, the decomposition of the electrolyte can be suppressed, and the decrease in battery capacity due to the deterioration of the electrolyte can be suppressed.

  In the overshoot charging step, the excess voltage Vq is preferably more than 100% and 130% or less of the target voltage Vp. In this case, charging can be performed in a short time while suppressing the decomposition of the electrolytic solution. When the over voltage Vq is excessively high with respect to the target voltage Vp, there is a possibility that the decomposition of the electrolytic solution may be excessive or the positive electrode active material may be damaged. When the non-aqueous secondary battery 5 reaches the excess voltage Vq during charging, the control unit 2 stops charging.

  It is preferable that current values at the time of charging in the overshoot charge step, the first charge-pause unit in the intermittent charge step, and the constant current constant voltage charge step be constant and equal to one another. Regardless of which process is selected, charging can be performed with a current value suitable for the non-aqueous secondary battery 5.

  The current value during charging in the overshoot charge process, initial charge-pause unit in intermittent charge process, and constant current constant voltage charge process should be 0.2 C rate or more and 3 C rate or less, and further 0.5 C rate The rate is preferably 2 C rate or less, and more preferably 0.7 C rate or more and 1.5 C rate or less. In this case, it is possible to charge to the excess voltage Vq in a short time while suppressing the decomposition of the electrolytic solution. If the current value is too low, the time required for charging may be too long. If the current value is excessive, the electrolyte may be decomposed by a side reaction during charging.

  The time required for the overshoot charge process is shorter than the time required for the intermittent charge process. Further, the time required for the overshoot charging step may be shorter than the time required for the constant current constant voltage charging step.

  Selection unit 27 selects constant current constant voltage charging unit 24 if temperature Tx of non-aqueous secondary battery 5 is determined to be less than predetermined value To in temperature determination unit 21, and non-aqueous secondary battery When it is determined that the temperature Tx of 5 is equal to or higher than the predetermined value To, the intermittent charging unit 25 or the overshoot charging unit 26 is selected. Selection unit 27 further selects intermittent charging unit 25 when it is determined in time determination unit 22 that charge allowable time Ha is equal to or longer than reference charge time Ho, and it is determined that charge allowable time Ha is less than reference charge time Ho. When it happens, the overshoot charging unit 26 is selected.

  The constant current constant voltage charging unit 24, the intermittent charging unit 25 and the overshoot charging unit 26 each include a known power conversion circuit. When any one of constant current constant voltage charging unit 24, intermittent charging unit 25 and overshoot charging unit 26 is selected by selection unit 27, the power conversion circuit of each charging unit causes the current to match the selected process. It is controlled. The controlled current is supplied to the non-aqueous secondary battery 5 in the vehicle 50 through the power extracting unit 59.

  The operation unit 3 has a start button 31 and a quick charge button 32. When the start button 31 is operated, charging of the charge control device 1 is started. When the start button 31 is operated and the quick charge button 32 is further operated, the overshoot charge process is selected when the temperature Tx of the non-aqueous secondary battery is equal to or higher than a predetermined value To.

  A charging method for charging the non-aqueous secondary battery 5 using the charge control device 1 will be described.

  When the charge control device 1 is connected to the electricity intake unit 51 of the vehicle 50 and the start button 31 is operated, charging by the charge control device 1 is started. Charging by the charge control device 1 is performed according to the flowchart shown in FIG.

  As shown in FIG. 2, in step S <b> 1, the control unit 2 confirms that the non-aqueous secondary battery 5 is stopped.

  In step S2, the temperature determination unit 21 determines whether the temperature Tx of the non-aqueous secondary battery 5 before charging is equal to or higher than a predetermined value To (temperature determination step). In step S2, if the temperature Tx of the non-aqueous secondary battery 5 before charging is equal to or higher than the predetermined value To (45 ° C.), the process proceeds to step S4. When the temperature Tx of the non-aqueous secondary battery 5 before charging is less than the predetermined value To (45 ° C.), the selection unit 27 selects the constant current constant voltage charging unit 24 in step S3.

  In step S3, the constant current constant voltage charging unit 24 performs a constant current constant voltage charging process. In the constant current constant voltage charging step, the non-aqueous secondary battery 5 is charged to a target voltage Vp (4.2 V) at a constant current of 1 C rate, and after the non-aqueous secondary battery 5 reaches the target voltage Vp, the target voltage Vp To keep the current while gradually reducing the current value.

  In step S4, time determination unit 22 determines whether or not charge allowable time Ha is equal to or longer than reference charge time Ho. The reference charging time Ho is a time until the net voltage of the non-aqueous secondary battery is made the target voltage Vp in the intermittent charging step. In order to determine the reference charge time Ho, repeat the charge-pause unit, which pauses for 1 hour after charging to the target voltage Vp (4.2 V) at a constant current of 1 C rate, and set the initial charge current value to 1 C rate Calculate the time required to repeat the charge rate from 0% to 100% as 1/3 of the current value of the charge of the previous charge-pause unit, and calculate the calculated value as the reference charge time. I will call it Ho. In the present embodiment, the reference charging time Ho calculated under the above conditions of the intermittent charging step was 3 hours.

  In step S4, when the quick charge button 32 is not operated, the time determination unit 22 determines that the charge allowable time Ha is equal to or longer than the reference charge time Ho. In this case, the selection unit 27 selects the intermittent charging process of step S5. On the other hand, when the quick charge button 32 is operated, the time determination unit 22 determines that the charge allowable time Ha is less than the reference charge time Ho. In this case, the selection unit 27 selects the overshoot charging unit 26 in step S6.

  In step S5, the intermittent charging unit 25 performs an intermittent charging process. In the intermittent charging step, the control unit 2 alternately repeats a charge-pause unit consisting of a charging step of charging the non-aqueous secondary battery 5 to the target voltage Vp and a pausing step of suspending charging temporarily. The current value supplied to the non-aqueous secondary battery 5 in the first charge-stop unit charging step was 1C. The current value in the charge step of each cycle of charge-rest unit is set to 1/3 of the current value of the charge step of the previous charge-rest step. The rest step in the charge-rest unit of each cycle was one hour. The charge-pause unit is repeated until the net voltage of the non-aqueous secondary battery 5 reaches the target voltage Vp. Alternatively, to set the net voltage of the non-aqueous secondary battery 5 to the target voltage Vp, the charge-pause unit may be repeated until the non-aqueous secondary battery 5 has a desired charge rate, preferably 100 Repeat until%. Alternatively, the charge-pause unit may be repeated until the voltage of the non-aqueous secondary battery 5 at the end of the pause step, that is, the voltage detected by the current detector 23 maintains 99% or more of the target voltage Vp. In the present embodiment, the charge-pause unit is repeated until the voltage of the non-aqueous secondary battery 5 at the end of the pause step maintains 99% or more of the target voltage Vp, and then the procedure is terminated.

  In step S6, the overshoot charge unit 26 performs an overshoot charge process. In the overshoot charge process, the overshoot charge unit 26 applies a constant current of 1 C rate to the non-aqueous secondary battery 5. When the constant current is continuously supplied to the non-aqueous secondary battery 5, the non-aqueous secondary battery 5 reaches the excess voltage Vq (4.35 V) exceeding the target voltage Vp (4.2 V). The excess voltage Vq of 4.35 V is 104% when the target voltage Vp is 100%. When the voltage of the non-aqueous secondary battery 5 reaches the excess voltage Vq, the overshoot charging unit 26 stops the constant current from flowing to the non-aqueous secondary battery 5, and ends the overshoot shooting process. Do.

  With the above, the charging of the non-aqueous secondary battery is completed.

  In the present embodiment, when it is determined that the temperature Tx of the non-aqueous secondary battery 5 is equal to or higher than the predetermined value To, the intermittent charging step or the overshoot charging step is performed. In the intermittent charging step, the step of temporarily stopping charging after charging with a constant current is performed to increase the charging depth and to eliminate the polarization in the positive electrode active material and the negative electrode active material while the electrolyte is decomposed due to an overvoltage. Can be suppressed. Further, in the pausing step, the heat generated in the charging step can be released to the outside, and the decomposition of the electrolytic solution can be suppressed. In the overshoot charge process, the non-aqueous secondary battery 5 is charged to the excess voltage Vq exceeding the target voltage Vp. When the non-aqueous secondary battery 5 is exposed to the excess voltage Vq higher than the target voltage Vp, the cell reaction proceeds positively, and the net voltage can be made the target voltage Vp in a short time. The time for which the non-aqueous secondary battery 5 is exposed to high temperature and high voltage can be short, so that the decomposition of the electrolyte can be suppressed, and the decrease in battery capacity due to the deterioration of the electrolyte can be suppressed.

  In particular, a lithium ion secondary battery using a Si-based material as a negative electrode active material has hysteresis in the charge / discharge curve, and the polarization in the electrode active material is large. Therefore, the decomposition reaction of the electrolytic solution can be suppressed and the battery life can be extended by performing the intermittent charging step or the overshoot charging step when the temperature of the non-aqueous secondary battery is high.

  Further, the intermittent charging process is performed when the allowable charging time Ha is equal to or more than the reference charging time Ho, and the overshoot charging process is performed when the allowable charging time Ha is less than the reference charging time Ho. For this reason, when sufficient time can be taken in charging at a high temperature, intermittent decomposition is performed while holding a pause during charging, thereby suppressing the decomposition of the electrolytic solution while eliminating the polarization in the electrode active material. be able to. When it is desired to charge in a short time, the reaction involving Li is positively advanced by charging up to the excess voltage Vq exceeding the target voltage Vp in the overshoot charging step to increase the potential difference between the positive and negative electrodes. By shortening the time for exposing the secondary battery 5 to high temperature and high voltage, it is possible to relatively suppress the decrease in capacity.

  On the other hand, when the temperature Tx of the non-aqueous secondary battery 5 is less than the predetermined value To, the temperature does not reach the temperature range where the decomposition of the electrolytic solution occurs. For this reason, in the constant current / constant voltage charging step, after charging with the constant current to the target voltage Vp, it is possible to suppress a decrease in battery life by charging until the net voltage reaches the target voltage Vp.

  The non-aqueous secondary battery 5 was subjected to a cycle test employing various charging methods of Tests 1 to 5 to measure the capacity retention rate after the cycle test.

(Non-aqueous secondary battery)
First, the configuration of a lithium ion secondary battery to be charged will be described. The positive electrode of the lithium ion secondary battery comprises a positive electrode active material layer and a current collector coated with the positive electrode active material layer. The positive electrode active material layer may contain a binder and a conductive aid as required.

The positive electrode active material layer has a positive electrode active material, a binder, and a conductive aid. The positive electrode active material is composed of a lithium-containing metal oxide having a layered rock salt structure represented by LiNi _0.5 Co _0.2 Mn _0.3 O ₂ and an olivine-type lithium phosphate composite oxide represented by LiFePO ₄ . The binder comprises polyvinylidene fluoride (PVDF). The conductive aid comprises acetylene black (AB). The current collector is made of aluminum foil. The content mass ratio of the positive electrode active material to the binder and the conductive additive is 94: 3: 3 when the positive electrode active material layer is 100 parts by mass. The above active material layer is coated on both sides of an aluminum foil so as to have a surface weight of 27.0 mg / cm ² , dried at 90 ° for 5 minutes, 120 ° for 5 minutes, and the n-methylpyrrolidone (NMP) is volatilized Removed. Thereafter, pressing was performed to a predetermined density, and then cut into a predetermined shape (a rectangular shape of 40 mm × 80 mm) to obtain a positive electrode.

The negative electrode is composed of a negative electrode active material layer and a current collector coated with the negative electrode active material layer. The negative electrode active material layer is composed of 58 parts by weight of a silicon material coated with carbon as a negative electrode active material, 24 parts by weight of natural graphite, 11 parts by weight of polyamideimide resin as a binder, and 7 parts by weight of acetylene black as a conductive additive. Become. The current collector is a copper foil. The above active material layer was coated on both sides of a copper foil so as to have a surface weight of 4.9 mg / cm ² and dried at 80 ° C. for 5 minutes to volatilize and remove NMP. Thereafter, pressing was performed to a predetermined density, and then cut into a predetermined shape (44 mm × 84 mm rectangular shape) to obtain a negative electrode.

The non-aqueous electrolytic solution is one in which a lithium salt is dissolved in an organic solvent. A mixed solvent of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (volume ratio 3: 3: 4) was used as an organic solvent, and LiPF ₆ was used as a lithium salt. The concentration of LiPF ₆ in the non-aqueous electrolyte was 1.0 mol / L.
A laminate type lithium ion secondary battery was produced as follows.

  A laminate-type lithium ion secondary battery was manufactured using the above two positive electrodes and three negative electrodes. Specifically, a rectangular sheet (48 mm × 88 mm, 25 μm thickness) made of a porous polyethylene film as a separator is sandwiched between the positive electrode and the negative electrode to form an electrode plate group. The electrode plate group was covered with a pair of laminate films, the three sides were sealed, and then an electrolytic solution was injected into the bag-like laminate film.

  The capacity at 0.2 C of the lithium ion secondary battery was 500 mAh.

  About the lithium ion secondary battery, a cycle test was performed under each of the conditions of the following tests 1 to 5, and the capacity retention rate after the cycle test was measured.

(Test 1)
The above-described lithium ion secondary battery was subjected to a constant current constant voltage charging step of constant voltage charging at a constant current. The charging conditions were: 25 ° C., charging at a constant current of 1 C rate and a constant voltage of 4.2 V. After the lithium ion secondary battery reached the target voltage Vp of 4.2 V, the current value was further decreased to maintain the target voltage of 4.2 V, and the battery was further charged. The termination current value was 0.1 C rate. The change of the voltage with the elapsed time of this constant current constant voltage charge was shown in FIG. 3, FIG.

  Discharge was performed after charging. Discharge conditions were 25 ° C. and 1 C rate.

  A cycle test was performed in which the constant current constant voltage charging step and the discharging step were repeated 200 times.

(Test 2)
In Test 2, a cycle test was performed in the same manner as in Test 1 except that the overshoot charge step was performed at 60 ° C. for the lithium ion secondary battery. In the overshoot charging step, charging was performed at 60 ° C. at a constant current of 1 C rate to 4.35 V which is the excess voltage Vq. The change of the voltage with the elapsed time of this overshoot charge process was shown in FIG. 4, FIG.

(Test 3)
In Test 3, a cycle test was performed in the same manner as in Test 1 except that the intermittent charging step was performed at 60 ° C. for the lithium ion secondary battery. In the intermittent charging step, charge-pause units were repeated three times at 60 ° C.

  In the intermittent charge step, the first charge-pause unit was charged to a target voltage of 4.2 V at a constant current of 1 C rate and then rested for 1 hour.

  Subsequently, the second charge-pause unit was charged to a target voltage of 4.2 V at a constant current of 1/3 C rate and then rested for 1 hour.

  The third charge-pause unit was charged to a target voltage of 4.2 V at a constant current of 1/9 C rate. This ended charging. The change of the voltage with the elapsed time of this intermittent charge process was shown in FIG. 5, FIG.

(Test 4)
In Test 4, a cycle test was performed in the same manner as Test 1 except that constant current charging was performed to 4.2 V at a constant current of 1/3 C rate during charging. The change of the voltage with the elapsed time of this constant current charge is shown in FIG.

(Test 5)
In the test 5, a cycle test was conducted in the same manner as the test 1 except that the temperature of the non-aqueous secondary battery at the time of charge was 60 ° C. The change of the voltage with the elapsed time of the constant current constant voltage charge of the test 5 was shown in FIG.

(Capacity maintenance rate)
It measured about the capacity | capacitance maintenance factor of the lithium non-aqueous secondary battery of the test 1-5, and the result was shown in Table 1. Table 1 shows the time required for charging in Tests 1 to 5. The discharge capacity retention rate is calculated as a percentage of a value obtained by dividing the discharge capacity after the cycle test by the first discharge capacity (100 × (discharge capacity after the cycle test) / (first discharge capacity)).

As shown in Table 1, in Tests 1 and 4 in which charging was performed at 25 ° C., the capacity retention rate was high. Tests 2 and 3 in which the battery was charged at 60 ° C. had slightly lower capacity retention than the tests 1 and 4 in which the battery was charged at 25 ° C. In Test 5, the capacity retention rate was significantly lower than in Tests 2 and 3. Test 5 is different from Test 1 in temperature, but both perform constant current constant voltage charging under the same conditions. However, in the test 5 in which the battery was charged at 60 ° C., the capacity retention rate was significantly lower than in the test 1 in which the battery was charged at 25 ° C. Tests 1 and 4 did not have much difference in capacity retention rate, but test 1 was shorter than test 4 in charge time. For the tests 2 and 3, the capacity retention rate was not significantly different, but for the charge time, the test 2 was shorter than the test 3.

  The shape of the lithium ion secondary battery is not particularly limited, and various shapes such as cylindrical, square, coin, and laminate types can be adopted.

  As mentioned above, although the embodiment of the lithium ion secondary battery of this invention and its manufacturing method was described, this invention is not limited to the said embodiment. In the range which does not deviate from the summary of the present invention, it can carry out with various forms which gave change, improvement, etc. which a person skilled in the art can make.

(1) The charging method of the non-aqueous secondary battery of the present embodiment is a charging method of charging the non-aqueous secondary battery and setting the net voltage of the non-aqueous secondary battery to the target voltage Vp.
A temperature determination step of determining whether the temperature of the non-aqueous secondary battery before charging is equal to or higher than a predetermined value To;
When it is determined in the temperature determination step that the temperature of the non-aqueous secondary battery is equal to or higher than a predetermined value To,
i) an intermittent charging step of alternately repeating a charge-pause unit consisting of a charging step of charging the non-aqueous secondary battery to the target voltage Vp and a pausing step of pausing the charging, or ii) targeting the non-aqueous secondary battery It is characterized in that an overshoot charging step of charging to an excess voltage Vq exceeding the voltage Vp is performed.

  According to the above configuration, when it is determined that the temperature Tx of the non-aqueous secondary battery is equal to or higher than the predetermined value To, the intermittent charging step or the overshoot charging step is performed. In the intermittent charging step, by putting the pause step after the charging step at a constant current, it is possible to suppress the decomposition of the electrolyte solution due to the overvoltage while aiming to eliminate the polarization in the electrode active material. Further, the heat generated by the charging can be released to the outside during the pausing of the pausing process, and the temperature increase of the battery can be suppressed. In the overshoot charge process, the non-aqueous secondary battery is charged to the excess voltage Vq exceeding the target voltage Vp. When the non-aqueous secondary battery is exposed to the excess voltage Vq higher than the target voltage Vp, the battery reaction proceeds positively, and the net voltage of the non-aqueous secondary battery can be made the target voltage in a short time. It takes less time to expose the non-aqueous secondary battery to high temperatures and high voltages, so that decomposition of the electrolytic solution can be suppressed, and a decrease in battery capacity due to deterioration of the electrolytic solution can be suppressed.

  (2) If it is determined in the temperature determination step that the temperature of the non-aqueous secondary battery is less than the predetermined value To, the non-aqueous secondary battery is charged with a constant current to the target voltage Vp, and the non-aqueous secondary battery is It is preferable to further include a constant current constant voltage charging step of further charging to maintain the target voltage Vp after reaching the target voltage Vp.

  According to the above configuration, when the temperature of the non-aqueous secondary battery is less than the predetermined value To, the temperature does not reach the temperature range where the decomposition of the electrolytic solution occurs. For this reason, in the constant current constant voltage charging step, charging is performed at a constant current to the target voltage Vp, and thereafter held at a constant voltage, and the net voltage of the non-aqueous secondary battery is made the target voltage Vp. It is possible to suppress the decrease in life.

  (3) The intermittent charging process is selected when the allowable charging time Ha that can be spent charging the non-aqueous secondary battery is longer than the reference charging time Ho, and the overshoot charging is performed when the allowable charging time Ha is less than the reference charging time Ho It is preferable to further include a selection step of selecting a step.

  According to the above-mentioned configuration, when sufficient time can be taken in charging at high temperature, by performing intermittent charging with a pause during charging, it is possible to eliminate the polarization in the electrode active material while decomposing the electrolyte. Can be suppressed. When it is desired to charge in a short time, the reaction involving Li is positively advanced by charging up to the excess voltage Vq exceeding the target voltage Vp in the overshoot charging step to increase the potential difference between the positive and negative electrodes. By shortening the time for which the secondary battery is exposed to high temperature and high voltage, the decrease in capacity can be relatively suppressed.

  (4) It is preferable to further include a time determination step of determining whether or not the allowable charging time Ha is equal to or longer than the reference charging time Ho.

  According to the above configuration, it can be selected whether or not the charging time can be selected according to the charging allowable time Ha.

  (5) In the intermittent charging step, the current value of the charging in the charging step of the charging-pause unit is preferably smaller than the current value of the charging in the charging step of the charging-pause unit immediately before. .

  According to the above configuration, the voltage inside the electrode active material can be increased to increase the charging depth, and the entire battery can be uniformly set to the target voltage Vp. Moreover, the voltage error due to the internal resistance of the battery can be suppressed. Thereby, the net voltage of the non-aqueous secondary battery can be brought close to the target voltage Vp.

  (6) It is preferable that current values at the time of charging in the first charging-pause unit in the intermittent charging step, the overshoot charging step, and the constant current / constant voltage charging step be constant and equal to each other.

  If the current value during charging is different in each process, it is necessary to change the battery design for each current value. As in the above configuration, any process can be performed by setting the current values at the time of charging in the first charging-pause unit in the intermittent charging process, the overshoot charging process, and the constant current constant voltage charging process constant and equal to each other. Even in the case, the current suitable for the battery can be supplied.

  (7) Charging in the Intermittent Charging Step In the pause step of the pause unit, it is preferable to pause charging until the non-aqueous secondary battery becomes lower than the target voltage Vp.

  According to the above configuration, the applied voltage can be uniformly spread over the entire electrode active material, and the charging depth can be deepened.

  (8) In the intermittent charging step, it is preferable to end the repetition of the charge-pause unit when the voltage of the non-aqueous secondary battery at the end of the pause step maintains 90% or more of the target voltage Vp.

  According to the above configuration, the applied voltage can be uniformly spread over the entire electrode active material, and the charging depth can be deepened.

  (9) In the overshoot charging step, the excess voltage Vq is preferably more than 100% and 130% or less of the target voltage Vp.

  According to the above configuration, charging can be performed in a short time while suppressing the decomposition of the electrolytic solution.

(10) The charge control device 1 of the present invention controls the current supplied to the non-aqueous secondary battery in charging the non-aqueous secondary battery 5 and setting the net voltage of the non-aqueous secondary battery 5 as the target voltage. Control unit 2, and
The control unit 2
A temperature determination unit 21 that determines whether the temperature Tx of the non-aqueous secondary battery 5 before charging is equal to or higher than a predetermined value To;
An intermittent charge unit 25 alternately repeating a charge-pause unit consisting of a charge step of charging the non-aqueous secondary battery 5 to the target voltage Vp and a pause step of pause the charge temporarily;
An overshoot charge unit 26 for charging the non-aqueous secondary battery 5 to an excess voltage Vq exceeding a target voltage Vp;
And a selection unit 27 for selecting one of the intermittent charging unit 25 and the overshoot charging unit 26 when the temperature judgment unit 21 determines that the temperature Tx of the non-aqueous secondary battery 5 is equal to or higher than a predetermined value To. It is characterized by having.

  According to the above configuration, when it is determined that the temperature Tx of the non-aqueous secondary battery 5 is equal to or higher than the predetermined value To, the intermittent charging step or the overshoot charging step is performed. In the intermittent charging step, the pause step is inserted after the charging step at a constant current to promote the diffusion of Li ions into the electrode active material to eliminate the polarization in the battery, and to decompose the electrolyte solution due to the overvoltage. It can be suppressed. Further, the heat generated by the charging can be released to the outside during the pausing of the pausing process, and the temperature increase of the battery can be suppressed. In the overshoot charge process, the non-aqueous secondary battery is charged to the excess voltage Vq exceeding the target voltage Vp. When the non-aqueous secondary battery is exposed to the excess voltage Vq higher than the target voltage Vp, the battery reaction proceeds positively, and the net voltage of the non-aqueous secondary battery can be made the target voltage in a short time. It takes less time to expose the non-aqueous secondary battery to high temperatures and high voltages, so that decomposition of the electrolytic solution can be suppressed, and a decrease in battery capacity due to deterioration of the electrolytic solution can be suppressed.

(11) The control unit 2 charges the non-aqueous secondary battery to a target voltage Vp with a constant current, and further charges the non-aqueous secondary battery to maintain the target voltage Vp after reaching the target voltage Vp. The constant voltage charging unit 24 is further provided,
It is preferable that the selection unit 27 select the constant current constant voltage charging process when the temperature determination unit 21 determines that the temperature Tx of the non-aqueous secondary battery is less than the predetermined value To.

  According to the above configuration, when the temperature Tx of the non-aqueous secondary battery is less than the predetermined value To, the non-aqueous secondary battery does not reach a temperature range where decomposition of the electrolytic solution occurs. For this reason, in the constant current / constant voltage charging step, by charging with the constant current to the target voltage Vp and then holding it at the constant voltage, it is possible to suppress a decrease in life in a short time.

(12) The control unit 2 further includes a time determination unit 22 that determines whether or not the allowable charging time Ha is equal to or longer than a reference charging time Ho that can be spent charging the non-aqueous secondary battery,
Selection unit 27 selects intermittent charge unit 25 when charge allowable time Ha is equal to or longer than reference charge time Ho in the time determination unit, and selects overshoot charge unit 26 when charge allowable time Ha is less than reference charge time Ho. Is preferred.

  According to the above configuration, when sufficient time can be taken at the time of charging at high temperature, by performing intermittent charging with a pause during charging, it is possible to suppress the decomposition of the electrolytic solution while eliminating the polarization in the electrode. can do. When it is desired to charge in a short time, the reaction involving Li is positively advanced by charging up to the excess voltage Vq exceeding the target voltage Vp in the overshoot charging step to increase the potential difference between the positive and negative electrodes. By shortening the time for which the secondary battery is exposed to high temperature and high voltage, the decrease in capacity can be relatively suppressed.

1: Charge control device 2: Control unit 21: Temperature determination unit 22: Time determination unit 23: Current detection unit 24: Constant current constant voltage charging unit 25: Intermittent charging unit 26: Overshoot charging unit , 27: selection unit, 3: operation unit, 31: start button, 32: quick charge button, 5: non-aqueous secondary battery, 50: electric car, 51: temperature sensor, 52: current measuring device, 6: power supply

Claims (11)

A charging method for charging a non-aqueous secondary battery and setting a net voltage of the non-aqueous secondary battery as a target voltage,
A temperature determination step of determining whether the temperature of the non-aqueous secondary battery before charging is equal to or higher than a predetermined value;
When it is determined in the temperature determining step that the temperature of the non-aqueous secondary battery is equal to or higher than a predetermined value,
i) an intermittent charging step of alternately repeating a charge-pause unit comprising a charging step of charging the non-aqueous secondary battery to the target voltage and a pausing step of pausing the charging temporarily, or ii) the non-aqueous secondary battery And overshoot charging to charge the battery to an excess voltage exceeding the target voltage ,
The intermittent charging step is selected when the allowable charge time for charging the non-aqueous secondary battery is equal to or greater than the reference charge time, and when the allowable charge time is less than the reference charge time, the overshoot charge step is selected. A method of charging a non-aqueous secondary battery comprising a selection step to be selected .   When it is determined in the temperature determination step that the temperature of the non-aqueous secondary battery is less than a predetermined value, the non-aqueous secondary battery is charged to a target voltage with a constant current, and the non-aqueous secondary battery is The method for charging a non-aqueous secondary battery according to claim 1, further comprising a constant current constant voltage charging step of further charging so as to maintain the target voltage after reaching the target voltage. The method for charging a non-aqueous secondary battery according to claim 1 , further comprising a time determination step of determining whether the charge allowable time is equal to or longer than the reference charge time. 4. The intermittent charge process according to claim 1 , wherein the current value of the charge in the charge process in the charge-pause unit is smaller than the current value in the charge process in the charge-suspension unit immediately before. The charging method of the non-aqueous secondary battery in any one. The first charge-pause unit in the intermittent charge step, the overshoot charge step, and the non-aqueous secondary battery are charged to a target voltage with a constant current, and the non-aqueous secondary battery reaches the target voltage 5. The method of charging a non-aqueous secondary battery according to claim 2 , wherein the current values at the time of charging in the constant current constant voltage charging step of further charging so as to maintain the target voltage later are constant and equal. The non-aqueous secondary according to any one of claims 1 to 5 , wherein the non-aqueous secondary battery is suspended until the non-aqueous secondary battery becomes lower than the target voltage in the pause step of the charge-pause unit in the intermittent charge step. How to charge the battery. In the intermittent charging process, the voltage of the nonaqueous secondary battery during the rest step completed the charging when maintaining more than 90% of the target voltage - any of claims 1 to 6 to end repetition of the resting units A method of charging a non-aqueous secondary battery according to any one of The method for charging a non-aqueous secondary battery according to any one of claims 1 to 7 , wherein in the overshoot charging step, the excess voltage is more than 100% and is 130% or less with respect to the target voltage. A control unit is provided to control the current supplied to the non-aqueous secondary battery in order to charge the non-aqueous secondary battery and set the net voltage of the non-aqueous secondary battery as a target voltage,
The control unit
A temperature determination unit that determines whether the temperature of the non-aqueous secondary battery before charging is equal to or higher than a predetermined value;
An intermittent charging unit that alternately repeats a charge-pause unit consisting of a charging step of charging the non-aqueous secondary battery to the target voltage and a pausing step of pausing the charging temporarily;
An overshoot charging unit for charging the non-aqueous secondary battery to an excess voltage exceeding the target voltage;
Providing a selection unit for selecting one of the intermittent charging unit and the overshoot charging unit when the temperature judgment unit judges that the temperature of the non-aqueous secondary battery is equal to or higher than a predetermined value. Characteristic charge control device. The control unit charges the non-aqueous secondary battery with a constant current to a target voltage, and further charges the non-aqueous secondary battery to maintain the target voltage after the non-aqueous secondary battery reaches the target voltage. It further has a charging unit,
10. The charge control device according to claim 9 , wherein the selection unit selects the constant current constant voltage charging unit when the temperature determination unit determines that the temperature of the non-aqueous secondary battery is less than a predetermined value. . The control unit further includes a time determination unit that determines whether or not the charge allowance time that can be spent for charging the non-aqueous secondary battery is equal to or greater than a reference charge time.
The selection unit selects the intermittent charge unit when the charge allowable time is equal to or longer than the reference charge time in the time determination unit, and selects the overshoot charge unit when the charge allowable time is less than the reference charge time. The charge control device according to claim 9 or 10 .

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