JP5987298B2 - Lithium-ion battery charging method - Google Patents

Description

  The present invention relates to a charge / discharge system for a lithium ion battery configured by connecting a plurality of lithium ion batteries (hereinafter also simply referred to as batteries) in series, and more particularly to a charge / discharge system for facilitating monitoring and management.

In a high-power system using a battery as a main power source, it is common to increase the capacity by connecting a large number of single cells in series and parallel.
By the way, when a battery power source composed of a large number of batteries connected in series and parallel is collectively charged, there is a problem in that the amount of charge varies due to the characteristic variation of each battery and the total amount of charge decreases. In this case, if charging is continued to increase the charge amount of the battery whose charge amount has decreased, there is a problem that the battery that is already fully charged becomes overcharged.

FIG. 8 shows an example of charge / discharge operation when 10 batteries B1 to B10 are connected in series. FIG. 4A shows an initial discharge state, FIG. 4B shows a discharge end state, FIG. 3C shows a state of the charging operation 1, and FIG.
Here, the initial discharge state is assumed to be new or fully charged. The discharge operation can be expressed as follows: VBd = eB−IB × RB (1)
Here, VBd: battery terminal voltage during discharge, eB: battery electromotive voltage, -IB: discharge current, and RB: internal resistance, respectively.

Now, when the discharge current -IB flows, the B1 battery voltage VB1 becomes the electromotive voltage eB1 = level-1 and the voltage drop IB × RB1 = level-1 due to the battery internal resistance, so that the battery voltage VB1 = level-2. Further, the B2 battery voltage VB2 is the electromotive voltage eB2 = level-2, the voltage drop IB × RB2 = level-2 due to the battery internal resistance, and thus the battery voltage VB2 = level-4. Similarly, the B3 battery voltage VB3 is the electromotive voltage. eB3 = level-3, voltage drop due to battery internal resistance IB × RB3 = level-3, and thus battery voltage VB3 = level-6.
The same applies to the other batteries B4 to B10. Due to variations in the internal resistance of the individual batteries, the battery internal voltage drop values differ as indicated by the black frame, resulting in differences in the individual battery voltages VB1 to VB10. The voltage VBd across the series battery is
VBd = VB1 + VB2 + VB3 + VB4 + VB5 + VB6 + VB7 + VB8 + VB9VB10
It is.

FIG. 9 shows the relationship between the internal resistance change of the battery and the charge capacity (remaining amount).
As shown, the internal resistance RB tends to be small when the remaining amount is large (full charge), and the internal resistance RB tends to be large when the remaining amount is small (end of discharge). Further, the internal resistance RB increases with cycle life and calendar life.
The end-of-discharge state shown in FIG. 8B shows a state in which the variation in internal resistance of each battery is expanded by a plurality of charge / discharge operations. That is, the voltage drop of the B1 battery is increased from level-1 to level-4, the voltage drop of the B2 battery is increased from level-2 to level-8, and the voltage drop of the B3 battery is increased from level-3 to level-12. In particular, it can be seen that the battery B3, B6, B9 has a large variation in characteristics.

FIG. 8C shows a charging operation 1 when 10 series-connected battery groups are collectively charged from this state.
The charging operation is expressed by the following equation.
VBc = eB + IB × RB (2)
Here, VBc: battery terminal voltage during charging, eB: battery electromotive voltage, + IB: charging current, RB: internal resistance.
Due to the charging current + IB, the applied voltage VB1 of the B1 battery = level + 1, and the voltage drop IB × RB1 = level + 1⇒level-1 (black frame) due to the battery internal resistance, so that the electromotive voltage eB1 = level-1. Further, the applied voltage VB2 of the B2 battery = level 0, the voltage drop IB × RB2 = level 0 → level-3 (black frame) due to the battery internal resistance, and therefore the electromotive voltage eB2 = level-3, and similarly the applied voltage VB3 of the B3 battery = Level-1, voltage drop due to battery internal resistance IB × RB3 = level-1 => level-5 (black frame), therefore, electromotive voltage eB3 = level-5.

As described above, the difference in battery internal resistance causes a difference in the battery internal voltage drop value (black frame), resulting in a difference in the terminal voltage VB and the electromotive voltage eB of each battery. That is, the electromotive voltages vary as follows: B1 battery electromotive voltage = eB1, B2 battery electromotive voltage = eB2, B3 battery electromotive voltage = eB3. Note that the voltage VBc across the series battery at this time is
VBc = VB1 + VB2 + VB3 + VB4 + VB5 + VB6 + VB7 + VB8 + VB9VB10
It is.

Since the electromotive voltage value indicates the amount of charge, the B1 battery has a large charge amount, the charge amount of the B2 battery is medium, and the charge amount of the B3 battery is small. Total electromotive voltage = total charge amount decreases.
Here, in order to increase the charge amount of the B3 battery with a small charge amount, when the charge voltage VBc is increased and charged, the four-step voltage increases from the B3 battery electromotive voltage eB3 level-5 to the level-1 (dotted line frame display) However, since the B1 battery electromotive voltage eB1 level-1 rises to +3 and the B2 battery electromotive voltage eB2 level-3 rises to the level + 1, the B1 and B2 batteries are in an overcharge operation state. In this way, when the series-connected lithium ion batteries are collectively charged, the total capacity is reduced due to variations in individual battery characteristics, and when the batteries with reduced capacity are additionally charged, other batteries that have not been reduced in capacity are overcharged.

  By the way, as a supplementary charging method for correcting the charging variation, for example, there is a method described in Patent Document 1 (Japanese Patent No. 4148468).

Japanese Patent No. 4148468

However, the one described in Patent Document 1 is made for a case where a plurality of batteries are connected in parallel, not for a case where a plurality of batteries are connected in series.
Therefore, in the battery power source in which a plurality of individual batteries are connected in series, the present invention is to correct the decrease in the amount of charge caused by the characteristic variation of the individual batteries by supplementary charging and to prevent overcharging of the individual batteries. . Also, the internal resistance and electromotive voltage of each battery can be monitored and managed, and when an abnormality occurs, the charge / discharge operation is stopped and an alarm can be issued.

In order to solve such a problem, in the invention of claim 1, a group of lithium ion batteries in which a plurality of lithium ion batteries are connected in series, a charging / discharging device for charging the group of lithium ion batteries, Switching means for individually selecting and connecting the charging / discharging device to the first group of lithium ion batteries or the individual lithium ion batteries is provided, and the charging / discharging device is connected to the first group of lithium ion batteries by the switching means, or In the method of charging a lithium ion battery that is individually connected to an individual lithium ion battery to charge the group of lithium ion batteries or the individual lithium ion battery,
The charging / discharging device is constituted by a generator and a chopper that lowers the output voltage of the generator to the voltage of the individual lithium ion battery, and the group of lithium ion batteries is collectively collected by the generator of the charging / discharging device. after charging to the monitored individually charge and discharge states of the individual lithium ion battery, when the battery voltage is detected low lithium ion battery than a preset specified value, the detected voltage The auxiliary charging is performed by individually switching and connecting the generator of the charging / discharging device to the low individual lithium ion battery through the chopper .

The invention of claim 2 includes a group of lithium ion batteries in which a plurality of lithium ion batteries are connected in series, a charging / discharging device for charging the group of lithium ion batteries, and the charging / discharging device of the group of lithium ions. Switching means for individually selecting and connecting to an ion battery or an individual lithium ion battery is provided, and the charging / discharging device is individually connected to the group of lithium ion batteries or the individual lithium ion batteries by the switching means. In the method of charging a lithium ion battery in which the first group of lithium ion batteries or an individual lithium ion battery is charged,
The charging / discharging device comprises a generator and a chopper that steps down the output voltage of the generator to the voltage of the individual lithium ion battery, and the plurality of lithium ion batteries are connected in series by the generator of the charging / discharging device. After charging the group of lithium ion batteries collectively, the charge / discharge state of the lithium ion batteries was individually monitored, and individual lithium ion batteries having a battery voltage lower than a preset specified value were detected. When disconnecting the series connection of the individual lithium ion batteries of the first group of lithium ion batteries, the generator of the charge / discharge device is connected to all of the detected individual lithium ion batteries having a low voltage, Supplementary charging is performed by connecting in parallel via the chopper .
In the first or second aspect of the present invention, the battery internal resistance and the battery electromotive voltage are obtained from the battery voltage when the same current is passed during charging and discharging, and the lithium ion battery is either individually connected or connected in series. In this case, it is possible to monitor and manage the characteristic state of each battery (invention of claim 3 ).

According to the present invention, in a battery power source in which a plurality of individual batteries are connected in series, a configuration in which supplementary charging can be performed individually enables individual correction of variations and suppresses a decrease in the total charge amount of series-connected batteries. To do. In addition, the internal resistance and electromotive force of the battery are calculated from the terminal voltage of the individual battery or series-connected battery group when the same current is passed between charge and discharge, and the battery state is determined in either the individual connection or series connection state. Enable monitoring and management.
Furthermore, since there is a charging method for correcting variations in parallel-connected batteries as described in Patent Document 1, supplementary charging for variation in characteristics of series-parallel batteries can be performed by using this and this invention method in combination. It is possible to suppress a decrease in the total charge amount of all the batteries.

Partial block diagram showing the first embodiment of the present invention Partial configuration diagram showing a modification of FIG. 1A More specific configuration diagram of FIG. 1A Partial configuration diagram showing a second embodiment of the present invention Explanatory diagram of charging operation in the case of FIG. 1A, 1B and FIG. Charge operation explanatory diagram in the case of FIG. Circuit diagram showing charge / discharge operation of series-connected batteries Explanatory diagram of charge / discharge operation of FIG. Detailed configuration diagram showing an application example corresponding to FIGS. 1A, 1B, and 2 Detailed configuration diagram showing an application example corresponding to FIG. 1B Explanatory drawing for demonstrating the charging / discharging operation | movement of a battery Explanatory drawing explaining the internal resistance change example of a battery

FIG. 1A is a block diagram showing a first embodiment of the present invention.
In the figure, B1 to B10 are batteries, 12 (SWL), 17 (SWG), SWP, SWN, SWPS, and SWNS are switches, 13 (L) is a load, 14 (G) is a generator, and 23 (CH) is a switch. Shows chopper.
This is an example in which the batteries B1 to B10 are charged via the chopper 23. In this case, the output voltage G of the generator 14 is set to (1 / series battery connection number n) by the chopper 23, and the connection point PS / NS is set. Connect to each battery to charge. The switches SWPS and SWNS may be mechanical contact switches, or a semiconductor switch shown in FIG. 1B or a bidirectional semiconductor switch shown in FIG. In addition, since FIG. 1B is a thing which abbreviate | omitted the chopper from FIG. 1A, suppose that it treats as the substantially same thing below.

  Monitoring and management of the charge / discharge operation status of each battery is performed by taking in battery voltages VB1 to VB10 detected by a voltage detector (not shown) by a battery charge / discharge & status monitoring control device (not shown), and based on this, the battery internal resistance and occurrence For example, the voltage is obtained and compared with a specified value. As a result, for example, when it is determined in FIG. 8 that the batteries B3, B6, B9 are the variation batteries exceeding the specified value, these batteries are selected, and the output voltage of the generator 14 or the chopper 23 is changed to the switch SWPS-PS. , SW3-NS is applied to the B3 battery for charging. When the charging of the B3 battery is completed, the battery is switched to the B6 battery. When the charging is completed, the battery is switched to the B9 battery. When the charging is completed, the battery is charged. Variations can be corrected by completing (supplementary charging).

FIG. 2 shows an example in which the bidirectional semiconductor switch is used in FIG. 1A. This bidirectional semiconductor switch
For example, it is shown in Japanese Patent No. 4333659.
In this circuit, for example, when the battery B1 is charged, when the P-side Q1 and the N-side Q1 of the bidirectional semiconductor switch SWB1 are turned on, the power supply P starts from the diode D13⇒P side Q1⇒diode D12⇒battery B1⇒diode D1⇒N side. Charging current flows from Q1 to diode D14 to power source N. In this circuit, only one charge is performed at the same time. This is because when two bidirectional semiconductor switches of two batteries are simultaneously turned ON, a short circuit occurs between the two batteries.

Therefore, only one auxiliary charge is used here, and when the auxiliary charge is completed, the auxiliary charge of the next battery is completed. FIG. 4A shows the charging operation in this case.
FIGS. 4A and 4B show a constant voltage charging operation, in which the generator output voltage VG is adjusted to VB by the chopper 23 and then applied to each battery for charging. At time t1 in FIG. 4A, SWB3 is turned on to start constant voltage charging of the B3 battery. When the charging current IB3 reaches a preset IBE, SWB3 is turned off, and then SWB6 is turned on to charge the B6 battery at constant voltage. When the charging current IB6 reaches the preset IBE, the SWB6 is turned off, and then the SWB9 is turned on to start constant voltage charging of the B9 battery. When the charging current IB9 reaches the preset IBE, the SWB9 is turned off. Then, individual charging of a group of batteries is completed.

4A (c) and 4 (d) show a constant current charging operation, in which the generator output current IG is adjusted with a chopper and then applied to each battery for charging. At time t1, SWB3 is turned on to start constant current charging of the B3 battery. When the battery voltage VB3 reaches a preset VBE, SWB3 is turned off, and then SWB6 is turned on to start constant current charging of the B6 battery. When the battery voltage VB6 reaches the preset VBE, the SWB6 is turned off, and then the SWB9 is turned on to start constant current charging of the B6 battery. When the battery voltage VB9 reaches the preset VBE, the SWB9 is turned off Complete individual charging of the battery.
FIG. 8D shows an example of charging operation 2 in which the electromotive voltage level of the batteries B3, B6, and B9 having large variations in FIG. .

Next, a method for monitoring and managing the characteristic state of each battery will be described. Here, the terminal voltage of each battery is detected by supplying the same current during charging and discharging.
At the time of discharging, the switch SWG is turned off to disconnect the generator 14 and the chopper 23 is stopped. On the other hand, the switch SWL is turned on and the switch SWB of the battery to be selected is turned on. Adjust) and measure the battery terminal voltage. The battery terminal voltage at the time of charging / discharging is represented by the above formulas (1) and (2).
During discharge: VBd = eB−IB × RB (1)
During charging: VBc = eB + IB × RB (2)

From the above formulas (1) and (2), the electromotive voltage eB during charging is lower than the terminal voltage VBc by a voltage drop, and the electromotive voltage eB during discharging is higher than the terminal voltage VBd by a voltage drop. . Therefore, from the terminal voltages VBc and VBd when substantially the same current flows at the time of charging and discharging,
Voltage difference ΔVB = VBd−VBc = 2 × (IB × RB) (3)
Internal resistance value RB = (ΔVB ÷ IB) / 2 (4)
Electromotive voltage eB = VB−IB × RB (5)
As described above, since the internal resistance and the electromotive voltage can be calculated from the terminal voltage of each battery in the charge / discharge operation, the characteristics of each battery can be monitored and managed using this.

  FIG. 3 shows an example different from FIGS. 1A and 1B and FIG. This is different from that shown in FIG. 2 in that switches DS1 to DS10 are inserted between the batteries to perform charging. Since this circuit does not form a short circuit, a plurality of selected batteries can be placed in parallel to perform supplementary charging at the same time. For example, the switches SWB3, SWB6, and SWB9 are simultaneously turned on to enable supplementary charging.

The charging operation in the case of FIG. 3 is shown in FIG. 4B. 4B (a) and 4 (b) show a constant voltage charging operation, in which the chopper is controlled at a constant voltage and each battery is charged with the output voltage VBCH.
At time t1 in FIG. 4B, the switches SWB3, SWB6, and SWB9 are simultaneously turned on to start constant voltage charging. When the charging current of each battery reaches the preset IBE, the corresponding battery is turned off to complete charging. For example, when the B3 battery reaches IBE, the SWB3 is turned off, and then when the B6 battery reaches IBE, the SWB6 is turned off. When the B9 battery reaches IBE, the SWB9 is turned off to complete the charging.
4B (c) and 4 (d) show a constant current charging operation, in which each battery is charged by performing constant current control of the chopper. Here, constant current charging is performed in a state where three batteries B3, B6, and B9 are connected in parallel. In this case, a pulse charging method is preferable. This is because the terminal voltages of the batteries connected in parallel are the same potential, and the charging state of the individual batteries cannot be monitored, so the charging method using the pulse charging method well known from the above-mentioned Patent Document 1 is optimal. is there.

When the output current of the chopper subjected to constant current control is supplied to the batteries B3, B6, B9 connected in parallel, the constant current control is performed by switching each battery in time series from time t1 as B3⇒B6⇒B9. . When the battery voltage of B3 reaches the preset VBE at time t2, the switch SWB3 of B3 is turned off to complete charging, and from time t2, B6⇒B9 are switched in chronological order to perform constant current charging, and time t3 When the battery voltage of B6 reaches the preset VBE, the switch SWB6 of B6 is turned off to complete charging, and only B9 is charged from time t3, and the battery voltage of B9 is preset to VBE at time t4. When it reaches, charging is completed.
Note that the output current value of the chopper in this charging operation is changed depending on the number of individual batteries. Moreover, when carrying out constant current charge continuously, the charging state of an individual battery shall be determined with a charging current.
The discharge operation is the same as in FIGS. 1A, 1B, and FIG.

FIG. 5 is a circuit diagram showing the charge / discharge operation of the series-connected batteries. This is different from that shown in FIG. 2 in that switches 3 (SWP2) 4 (SWQ) and 22 (SWT), voltage detectors 7 (VD1) and 8, current detector 10 (SHB) and the above-described battery charge / discharge & The difference is that a state monitoring control device 50 is added, and the others are the same.
In FIG. 5, when supplementary charging is performed individually, the switches SWP1, SWN1, and SWQ are turned off, the switches SWP2 and SWN2 are turned on, and the switch SWT is switched to the chopper (CH) 23 side. Thereby, the output voltage VBCH of the chopper (CH) 23 is applied to each battery via the switch 22 (SWT).
The battery charging / discharging & state monitoring control device 50 gives a control signal 66 for instructing a charging current and a charging voltage to the chopper (CH) 23 and gives a selection signal to the switch 5 so that the chopper output voltage VBCH is supplied to each battery. To charge each battery. Note that normal charging / discharging is performed by setting the switch 22 (SWT) to the normal side, the switches SWP2 and SWN2 are off, the switches SWP1 and SWN1 are on, and the switch SWQ is on and off.

An example of the charge / discharge operation of FIG. 5 is shown in FIG. FIG. 6A shows a charging operation, and FIG. 6B shows a discharging operation.
The battery charge / discharge & state monitoring control device 50 receives the voltage signal VB1 detected by the voltage detector 7 (VD1) of FIG. 5 and the voltage signal VBin detected by the voltage detector 8, and these values are preset. Compared with VBme (reference value), VBmx (allowable maximum value), VBmn (allowable minimum value), VBo (allowable excess high), and VBu (allowable excess low), the voltage is VBmx to VBmn in FIG. The batteries a, b, and c in the range are determined to be normal, and the batteries d, e, and f outside the range are determined to be abnormal. Here, the equation of operation at the time of charging is as in equation (2) above,
VBc = eB + IB × RB (2). In FIG. 6A, the battery d determines that the electromotive voltage eB exceeds the allowable value, and determines that it is in an overcharged state. Further, the battery e is determined to be a battery having a large internal resistance and a low electromotive voltage eB, and the battery f is determined to be an abnormal battery because the electromotive voltage eB is abnormally decreased.

  Thus, when the individual battery voltage exceeds the allowable range during the charging operation, for example, when a battery such as d is detected, the charging current or the charging voltage is reduced to suppress overcharging. However, if the overcharge state is not improved, an alarm is issued and the switch SWP1, SWN1, or SWQ is turned off to stop the charging operation. When a battery such as e is detected, the charging current or charging voltage is increased. However, when the voltage state is not improved, the switch SWP1, SWN1 or SWQ is turned off to stop the charging operation. Further, when a battery such as f is detected, it is abnormal, so that an alarm is issued and the switch SWP1, SWN1, or SWQ is turned off to stop the charging operation.

Next, the discharge operation of FIG. 5 will be described with reference to FIG. The operation equation is as follows.
VBd = eB−IB × RB (1)
As in the case of the above charging, the battery voltage management level is normal for the batteries a, b, and c in the range of VBmx to VBmn, and the batteries d, e, f, and g outside this range are abnormal levels. In this case, the battery d determines that the electromotive voltage eB exceeds the allowable value and is in an overload discharge state. Further, since the battery e has a large internal resistance and a low electromotive voltage eB, it is determined that the battery e is in an overdischarged state. f is determined to be a battery with an abnormally low electromotive voltage eB, and g is determined to be a reverse charge abnormally decreased battery due to a discharge current because the electromotive voltage is zero.
As described above, when the voltage of the individual battery exceeds the allowable range during the discharge operation of the series-connected batteries, the discharge current is reduced or the alarm is issued and the switch SWP1, SWN1 or SWQ is turned off to perform the discharge operation. Stop.

Obviously, the battery state can be monitored and managed in the charge / discharge operation of the series-connected batteries as well as in the past.
That is, from the series connection terminal voltages VBc and VBd when substantially the same current flows at the time of charging and discharging, it is expressed as the following equation, as in the previous equations (3) to (5).
Voltage difference ΔVB = VBd−VBc = 2 × (IB × ΣRB) (6)
Internal resistance value RB = (ΔVB ÷ IB) ÷ Σ (7)
Electromotive voltage ΣeB = VB−IB × ΣRB (8)
(Σ: Total value of series-connected batteries)
As described above, since the internal resistance and the electromotive voltage can be calculated from the terminal voltage in the battery series connection state, it is possible to monitor and manage the characteristics of each battery in the series connection state using this.

7A is an application diagram corresponding to FIGS. 1A, 2 and 5 above, 7B is an application diagram corresponding to FIG. 1B, and FIG. 7B is the same as FIG. 7A except that it does not have a chopper. The description will be given with reference.
FIG. 7A assumes an application example to a system for driving an electric vehicle, an electric propulsion ship or the like using a motor, and includes a generator control device 63 in addition to the motor 20 (M). The point is the feature. Also, reference numerals 6 (SHB1, SHBN), 18 (SHG) in the figure are current detectors, 9 (VBD), 19 (VDG) are voltage detectors, 11 (SWB), 21 (SWM), 51 (SWC). , 52 (SWS), 54 (SWP), 55 (SWS1), 64 (SWGE) are switches, 15 is a generator field (Gf), 53 (SCB) is a battery selector, and 56 (VRV) is a voltage setter. , 57 (VRI) indicate current setting devices, respectively.

Now, when the operation of the motor 20 (M) is stopped in FIG. 7A, charging / discharging of the individual batteries and charging / discharging of the series-connected batteries are as described above. Here, the charge / discharge operation of all the batteries connected in series will be described.
When charging all the batteries, the switch (SWC) 51 is set to “constant voltage”, “constant current” or “constant output (constant power)” as in the case of individual charging. Then, switch 2 (SWP1) is turned off, switch (SWN1) is turned on, switch 3 (SWP2, SWN2) is turned off, switch 4 (SWQ) is turned on and turned off, and switch 22 (SWT) is switched to the generator 14 (G) side. . The generator 14 (G) has a positive output (P) → switch 4 (SWQ) according to a predetermined output voltage (at constant voltage charging), output current (at constant current charging) or output power (at constant power charging). All batteries are charged through a path of ON → Battery 1 (B11 to B10) → Switch SWN1 → Negative electrode (N). Thereafter, the battery charge / discharge & state monitoring control device 50 indicates that the battery voltages VB1 to VBN detected by the voltage detector 7 (VD1) or the detected currents IB1 to IBN have reached a predetermined value by the current detector 6 (SHB1). Is determined, the switch 4 (SWQ) is turned off by the signal 60 to complete the charging.

As for the discharging operation, the switch 22 (SWT) is switched to the chopper side, the chopper 23 (CH) is stopped, the switch 4 (SWQ) is turned on to discharge the battery voltage to the load 13 (L), and charging and discharging are performed. The point of monitoring and managing the battery state from the battery voltage when the same current is passed is the same as described above.
In addition, since the voltage in the case of charging / discharging of all the batteries is detected by the voltage detector 8, it is of course possible to monitor and manage the operating states of all the batteries and the individual batteries.

  1 (B1 to B10) ... battery, 2,3,4,5,17,11,12,21,22 ... switch (SW), 6,10,18 ... current detector (SH), 7,8,9 , 19 ... Voltage detector (VD), 13 ... Load (L), 14 ... Generator (G), 15 ... Generator field (Gf), 16 ... Rectifier, 20 (M) ... Electric motor, 23 ... Chopper ( CH), 50 ... Battery charge / discharge & status monitoring and control device, 51 ... Charge switch (SWC), 52 ... Individual charge switch (SWS), 53 ... Battery selector (SCB), 54 ... Pulse charge switch (SWP), 55 ... Individual discharge switch (SWS1), 56 ... Voltage setter (VRV), 57 ... Current setter (VRI), 58 ... Battery status indicator, 63 ... Generator controller, 64 ... Operation switch (SWG).

Claims (3)

A group of lithium ion batteries in which a plurality of lithium ion batteries are connected in series, a charging / discharging device for charging the group of lithium ion batteries, and the charging / discharging device as the group of lithium ion batteries or individual lithium batteries Switching means for individually selecting and connecting to the ion battery is provided, and by this switching means, the charging / discharging device is individually connected to the group of lithium ion batteries or the individual lithium ion batteries to connect the group of lithium ions. In a method of charging a lithium ion battery that is charged with an ion battery or an individual lithium ion battery,
The charging / discharging device is constituted by a generator and a chopper that lowers the output voltage of the generator to the voltage of the individual lithium ion battery, and the group of lithium ion batteries is collectively collected by the generator of the charging / discharging device. after charging to the monitored individually charge and discharge states of the individual lithium ion battery, when the battery voltage is detected low lithium ion battery than a preset specified value, the detected voltage A charging method for a lithium ion battery, wherein the charging is performed by switching and connecting the generator of the charging / discharging device to a low individual lithium ion battery sequentially through the chopper . A group of lithium ion batteries in which a plurality of lithium ion batteries are connected in series, a charging / discharging device for charging the group of lithium ion batteries, and the charging / discharging device as the group of lithium ion batteries or individual lithium batteries Switching means for individually selecting and connecting to the ion battery is provided, and by this switching means, the charging / discharging device is individually connected to the group of lithium ion batteries or the individual lithium ion batteries to connect the group of lithium ions. In a method of charging a lithium ion battery that is charged with an ion battery or an individual lithium ion battery,
The charging / discharging device comprises a generator and a chopper that steps down the output voltage of the generator to the voltage of the individual lithium ion battery, and the plurality of lithium ion batteries are connected in series by the generator of the charging / discharging device. After charging the group of lithium ion batteries collectively, the charge / discharge state of the lithium ion batteries was individually monitored, and individual lithium ion batteries having a battery voltage lower than a preset specified value were detected. When disconnecting the series connection of the individual lithium ion batteries of the first group of lithium ion batteries, the generator of the charge / discharge device is connected to all of the detected individual lithium ion batteries having a low voltage, A charging method for a lithium ion battery, wherein the charging is performed by connecting in parallel through the chopper . The battery internal resistance and battery electromotive voltage are obtained from the battery voltage when the same current flows during charging and discharging, and the characteristic state of each battery is monitored whether the lithium ion battery is connected individually or in series. The method for charging a lithium ion battery according to claim 1 or 2, wherein management is enabled .

Images