JP4641862B2 - Lithium-ion secondary battery charge / discharge circuit - Google Patents

Description

  The present invention includes a plurality of battery circuit arrays connected in parallel to each other, and each of these battery circuit arrays includes a plurality of lithium ion secondary batteries connected in series with each other. It relates to the circuit.

  In general, lithium ion secondary batteries having a high volumetric energy density are frequently used in mobile radio communication devices such as mobile phones and cordless phones, as well as electronic devices such as video cameras and notebook computers. This lithium ion secondary battery is usually a battery circuit array in which a plurality of single cells are connected in series, and is used as a power source for electronic devices. When a larger current capacity is required, a plurality of batteries The circuit strings are connected in parallel to each other.

  Japanese Patent Application Laid-Open No. 2003-217675 discloses a charge / discharge circuit in which a bypass circuit is configured in parallel with each lithium ion secondary battery for one battery circuit array in which a plurality of lithium ion secondary batteries are connected in series with each other. ing. Each of these bypass circuits has IGBTs Q1, Q2, Q3,..., Qn, and these IGBTs have completed charging of the corresponding lithium ion secondary batteries, and their terminal voltages have reached the charging completion voltage. Sometimes it is turned on, the charging current for the corresponding lithium ion secondary battery is bypassed, and each lithium ion secondary battery can be charged in a well-balanced manner while preventing overcharging of the charged lithium ion secondary battery.

JP 2003-217675 A

  However, when a plurality of battery circuit arrays are connected in parallel to each other, since the charged lithium ion secondary batteries are bypassed, the charging current of the battery circuit arrays having a large number of fully charged lithium ion secondary batteries This results in delaying the charging of the lithium ion secondary battery in the other battery circuit array with a small number of fully charged lithium ion secondary batteries, so that all the lithium ion secondary batteries in all the battery circuit arrays are A disadvantage that the secondary battery cannot be charged efficiently occurs.

  The present invention includes a plurality of battery circuit arrays connected in parallel to each other, and is capable of charging and discharging lithium ion secondary batteries in each battery circuit array in a balanced and efficient manner. A circuit is proposed.

  A charging / discharging circuit of a lithium ion secondary battery according to the present invention includes a plurality of battery circuit arrays connected in parallel to each other, and each of these battery circuit arrays is connected to each other in series. A charge / discharge circuit for a lithium ion secondary battery including a bypass switch connected to each lithium ion secondary battery in each battery circuit row, each of the lithium ion secondary batteries reaching a charge completion voltage When the charging current is bypassed by the corresponding bypass switch, a current limiting circuit and a column control switch are connected in series with each of the lithium ion secondary batteries included in each of the battery circuit columns. When all the lithium ion secondary batteries included in each of the battery circuit arrays have reached the charging completion voltage , Characterized by an off the column control switches of the battery circuit row.

In the charging / discharging circuit of the lithium ion secondary battery according to the present invention, each bypass switch is connected to each lithium ion secondary battery in each battery circuit row, and when each of the lithium ion secondary batteries reaches the charge completion voltage, Since the charging current is bypassed by the corresponding bypass switch, each battery circuit row can be charged in a balanced manner while preventing overcharge of each lithium ion secondary battery. A current limiting circuit and a column control switch are connected in series with each of the lithium ion secondary batteries included in each of the batteries, and when all of the lithium ion secondary batteries included in the respective battery circuit columns reach the charging completion voltage In addition, since the row control switch of the battery circuit row is turned off, each lithium ion secondary battery is sequentially charged. Even if the charging current of each battery circuit row are balanced, effectively all of the lithium ion secondary batteries in all of the battery circuit array can be efficiently charged.

  Several embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is an electric circuit diagram showing Embodiment 1 of a charge / discharge circuit of a lithium ion secondary battery according to the present invention.

  As shown in FIG. 1, the charging / discharging circuit of the lithium ion secondary battery according to the first embodiment includes n battery circuit arrays 100, 200,..., N00, a charger 2, a control unit 3, It has a DC load 4 and n × n voltage detectors 5. The charger 2 has a positive electrode P and a negative electrode N, and the positive electrode P is connected to one end of the DC load 4 via a positive-side connection electric line 101P. The electric line 102P is connected. Further, the negative electrode N of the charger 2 is connected to the other end of the DC load 4 via the negative side connecting electric line 101N, and the negative side charging / discharging electric line 102N is connected to the negative side connecting electric line 101N. The battery circuit arrays 100, 200,..., N00 are connected in parallel to each other between the positive side charging / discharging circuit line 102P and the negative side charging / discharging circuit line 102N.

  In the first embodiment, n × n lithium ion secondary batteries 1a, 1b,..., 1n, 2a, 2b,..., 2n,. Including. These lithium ion secondary batteries are charged to a charging completion voltage of 4.1 volts by the charger 2 and then discharged for supplying power to the DC load 4.

  Each of the lithium ion secondary batteries 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., na, nb, ..., nn is referred to as a single cell. The battery circuit array 100 includes n unit cells 1a, 1b,..., 1n, and each unit cell 1a, 1b,. Are connected in series with the same polarity as The battery circuit array 200 includes n unit cells 2a, 2b,..., 2n, and each of the unit cells 2a, 2b,. Are connected in series with the same polarity as The battery circuit array n00 includes n unit cells na, nb,..., Nn, and each unit cell na, nb,. Are connected in series with the same polarity as

  The charger 2 supplies a charging current having a constant current value I to each of the battery circuit arrays 100, 200,..., N00, and the unit cells 1a, 1b,. 2a, 2b,..., 2n,..., Na, nb,. The charger 2 supplies a constant current of n × I to the positive-side charging / discharging circuit line 102P and the negative-side charging / discharging circuit line 102N when charging each unit cell.

  The battery circuit array 100 includes one column control circuit 10C and n battery control circuits 11C, 12C,..., 1nC. Similarly, the battery circuit array 200 includes one column control circuit 20C and n battery control circuits 21C, 22C,..., 2nC, and the battery circuit array n00 includes one column control circuit n0C, n Battery control circuits n1C, n2C,..., NnC.

The number of column control circuits 10C, 20C,..., N0C is the same as the number of battery circuit columns 100, 200,. It is connected to a position close to the charge / discharge circuit line 102P. These column control circuits 10 C , 20 C ,..., N0C are similarly configured. The column control circuit 10C includes a column control switch A10, a discharge diode B10, and a current limiting circuit 6. The column control switch A10 is directly connected to the current limiting circuit 6, and is connected in series with the current limiting circuit 6 and each of the single cells 1a, 1b,. The column control circuit 20C includes a column control switch A20, a discharge diode B20, and a current limiting circuit 6. The column control switch A20 is directly connected to the current limiting circuit 6, and the current limiting circuit 6 and each of the single cells 2a, 2b,. .. Connected in series with 2n. The column control circuit n0C includes a column control switch An0, a discharge diode Bn0, and a current limiting circuit 6. The column control switch An0 is directly connected to the current limiting circuit 6, and the current limiting circuit 6 and each single cell na, nb,. .., connected in series with nn.

  The column control switches A10, A20,..., An0 are configured by, for example, a pnp type IGBT, and each collector terminal is arranged with a polarity toward the positive charge / discharge circuit line 102P. Discharge diodes B10, B20,..., Bn0 are arranged with the opposite polarity, with the cathode facing the positive charging electric line 102P.

  The current limiting circuit 6 limits the charging current flowing through each of the battery circuit arrays 100, 200,..., N00 to a constant current value I. The current limiting circuit 6 detects, for example, the charging current of the battery circuit arrays 100, 200,..., N00, and limits it to the constant current value I when it is going to rise from the constant current value I. Although constituted by a detection type current limiting circuit, it can also be constituted by a constant current source type current limiting circuit for supplying a constant current value I to each battery circuit array 100, 200,..., N00.

  The battery control circuit 11C is disposed between the column control circuit 10C and the unit cells 1a, and controls the unit cells 1a. The battery control circuit 12C is disposed between the single cells 1a and 1b and controls the single cell 1b. The battery control circuit 1nC is disposed between the single cells 1n-1 and 1n and controls the single cell 1n. Similarly, the battery control circuit 21C is disposed between the column control circuit 20C and the unit cells 2a, and controls the unit cells 2a. The battery control circuit 22C is disposed between the single cells 2a and 2b and controls the single cell 2b. The battery control circuit 2nC is disposed between the single cells 2n-1 and 2n, and controls the single cell 2n. Similarly, the battery control circuit n1C is disposed between the column control circuit n0C and the single cell na, and controls the single cell na. The battery control circuit n2C is disposed between the single cells na and nb and controls the single cell nb. The battery control circuit nnC is arranged between the single cells nn−1 and nn and controls the single cell nn.

  Battery control circuits 11C, 12C, ..., 1nC, 21C, 22C, ..., 2nC, ..., n1C, n2C, ... nnC are the number of unit cells 1a, 1b, ..., 1n 2a, 2b,..., 2n,..., Na, nb,. The battery control circuit 11C includes a charge control switch A11, a discharge diode B11, and a bypass switch C11. The battery control circuit 12C includes a charge control switch A12, a discharge diode B12, and a bypass switch C12. The battery control circuit 1nC includes a charge control. It includes a switch A1n, a discharge diode B1n, and a bypass switch C1n. The battery control circuit 21C includes a charge control switch A21, a discharge diode B21, and a bypass switch C21. The battery control circuit 22C includes a charge control switch A22, a discharge diode B22, and a bypass switch C22. The battery control circuit 2nC includes a charge control. It includes a switch A2n, a discharge diode B2n, and a bypass switch C2n. Similarly, the battery control circuit n1C includes a charge control switch An1, a discharge diode Bn1, and a bypass switch Cn1, the battery control circuit n2C includes a charge control switch An2, a discharge diode Bn2, and a bypass switch Cn2, and the battery control circuit nnC , A charge control switch Ann, a discharge diode Bnn, and a bypass switch Cnn.

The charge control switches A11, A12, ..., A1n, A21, A22, ..., A2n, ..., An1, An2, ..., Ann are composed of, for example, a pnp type IGBT. The collector terminals are connected in series with the individual cells included in each of the battery circuit arrays 100, 200,..., N00 with the same polarity facing the positive charge / discharge circuit line 102P. The Discharge diodes B11, B12, ..., B1n, B21, B22, ... B2n , ... , Bn1 , Bn2, ..., Bnn are charge control switches A11, A12, ..., A1n. , A21, A22,..., A2n,..., An1, An2,..., Ann, and each cathode terminal is parallel with the same polarity facing the positive charge / discharge circuit line 102P. Connected to.

The bypass switches C11, C12, ..., C1n, C21 , C22, ..., C2n, ..., Cn1, Cn2, ..., Cnn are constituted by, for example, pnp type IGBTs. , 1n, 2a, 2b, ..., 2n, ..., na, nb, ..., nn, and charge control switches A11, A12, ... , A1n, A21, A22,..., A2n,..., An1, An2,. This bypass switch C11, C12, ..., C1n, C21, C22, ..., C2n, ..., Cn1, Cn2, ..., Cnn is a corresponding charge control switch A11, A12, ... , A1n, A21, A22,..., A2n,..., An1, An2, ..., Ann, and each collector terminal has a corresponding charge control switch A11, A12,. A1n, A21, A22, ..., A2n, ..., An1, An2, ..., Ann are connected to the collector terminals.

  Each voltage detector 5 detects the terminal voltage of each of the cells 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., na, nb, ..., nn. , 1n, 2a, 2b,..., 2n,..., Na, nb,. Sometimes, the charging completion detection signal S1 is supplied to the control unit 3.

When the control unit 3 receives the charging completion detection signal S1 from each voltage detector 5, the battery control circuits 11C, 12C,..., 1nC, 21C, 22C,. .., 2nC,..., N1C, n2C,. The charge stop signal S2, the bypass switch C11, C12 corresponding to the respective voltage detectors 5, ···, C1n, C21, C22, ···, C2n, ···, Cn 1, Cn2, ··· , Cnn from off to on, and charge control switches A11, A12,..., A1n, A21, A22,..., A2n,. ..., Ann is controlled from on to off.

The control unit 3 also includes all the unit cells 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ... in each of the battery circuit arrays 100, 200, ..., n00. , Or when na, nb,..., Nn reach the charge completion voltage, a column control signal S3 is generated, and this column control signal S3 is respectively supplied to the corresponding column control circuit 10 C , 20 C ,. n0 C. This column control signal S3 controls the corresponding column control switches A10, A20,..., An0 from on to off.

Next, the operation of the first embodiment will be described with reference to FIG. FIG. 2 is a chart for explaining the charging operation of the first embodiment. In Figure 2, the horizontal direction is placed on the upper, column control switches A10, · · ·, AN0, charge control switch A11, A12, ··· A1n, ··· , An1, An2, ··· Ann and bypass switch C11, C12,..., C1n,..., Cn1, Cn2,.

  In the leftmost column of FIG. 2, modes SS, 1A, 1B, 1N,..., NA, NB, and NN are arranged in the vertical direction. Mode SS is the initial charge state, mode 1A is the mode SS in which the unit cell 1a has reached the charge completion voltage, mode 1B is in mode 1A, and the unit cell 1b has been in the charge completion state, and mode 1N Indicates a state in which the unit cell 1n has reached the charge completion voltage in a state in which the unit cells 1a, 1b,..., 1 (n−1) have reached the charge completion voltage. This mode 1N means a state in which all the single cells 1a, 1b,.

  The mode NA is all the cells 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., (n) in the battery circuit array 100, 200, ..., (n-1) 00. n-1) a, (n-1) b,..., (n-1) In a state where n has reached the charging completion voltage, the mode NB is the mode in which the unit cell na has reached the charging completion voltage. The state in which the unit cell nb has reached the charging completion voltage at NA, and the mode NN is all the unit cells 1a, 1b,... In the battery circuit array 100, 200,. 1n, 2a, 2b, ..., 2n, ..., (n-1) a, (n-1) b, ..., (n-1) n, and a cell na in the battery circuit array n00 , Nb,..., N (n−1) has reached the charge completion voltage, and the cell nn has reached the charge completion voltage. It shows the state. In this mode NN, all the unit cells 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., na, nb in all the battery circuit arrays 100, 200, ..., n00 ,..., Means a state where nn has reached a state of completion of charging.

  First, in mode SS, all the column control switches A10, A20,..., An0 and all the charge control switches A11, A12,..., A1n, A21, A22,. , An1, An2,..., Ann are in the ON state, and all bypass switches C11, C12..., C1n, C21, C22,..., C2n,. , Cnn are in the off state. In this state, all the single cells 1a, 1b, and the like are connected from the charger 2 through the positive side connection circuit line 101P, the positive side charge / discharge circuit line 102P, the negative side connection circuit line 101N, and the negative side charge / discharge circuit line 102N. .., 1n, 2a, 2b,..., 2n,..., Na, nb,. Done.

  In the mode SS, each battery circuit array 100, 200,..., N00 is supplied with a charging current having a constant current value I from the charger 2, and all the unit cells 1a, 1b,. 2a, 2b,..., 2n,..., Na, nb,.

  In mode SS, it is assumed that the unit cell 1a first reaches the charge completion voltage of 4.1 volts, and this state is referred to as mode 1A. In this mode 1A, when the unit cell 1a reaches the charging completion voltage, the voltage detector 5 connected to the unit cell 1a generates the charging completion detection signal S1. In response to the charge completion detection signal S1 corresponding to the unit cell 1a, the control unit 3 supplies a charge stop signal S2 to the battery control circuit 11C, changes the bypass switch C11 from off to on, and turns on the charge control switch A11. To turn off.

In this mode 1A, in the battery circuit array 100, the unit cell 1a and the charge control switch A11 are short-circuited by the bypass switch C11, and the charging current of the constant current value I bypasses the unit cell 1a, and other unit cells 1b,.・ Supplied to 1n and charging of these cells continues. The unit cell 1a and the charge control switch A11 are short-circuited by the bypass switch C11. However, the constant current value I flowing through the battery circuit array 100 is suppressed from being increased by the current limiting circuit 6 of the column control circuit 10C, and a predetermined constant current is supplied. The value I is maintained.

In mode 1A, next, it is assumed that the cell 1b has reached the charging completion voltage of 4.1 volts, and this state is referred to as mode 1B. In this mode 1B, when the unit cell 1b reaches the charging completion voltage, the voltage detector 5 connected to the unit cell 1b generates the charging completion detection signal S1. In response to the charging completion detection signal S1 corresponding to the single cell 1b, the control unit 3 supplies a charging stop signal S2 to the battery control circuit 12C, changes the bypass switch C12 from off to on, and turns on the charging control switch A12. To turn off.

In the mode 1B, in the battery circuit array 100, the cells 1a and 1b and the charge control switches A11 and A12 are short-circuited by the bypass switches C11 and C12, and the charging current of the constant current value I bypasses the cells 1a and 1b. Are supplied to the single cells 1c,..., 1n, and charging of these single cells continues. Even if the unit cell 1b and the charge control switch A12 are short-circuited by the bypass switch C12, the constant current value I flowing through the battery circuit array 100 is suppressed from rising by the current limiting circuit 6 of the column control circuit 10C and reaches mode 1N. Until this time, the constant current value I is maintained, and the unit cell that has not been charged by the constant current value I is charged with constant current.

All of the cells 1a, 1b,..., 1 (n−1) in the battery circuit array 100 reach the charging completion voltage of 4.1 volts, and the corresponding bypass switches C11, C12,. -1) is turned on, and the corresponding charging control switches A11, A12,..., A1 (n-1) are turned off, the unit cell 1n reaches the charging completion voltage of 4.1 volts. This state is referred to as mode 1N. In this mode 1N, the entire terminal voltage of the battery circuit array 100 reaches n × 4.1 volts. In this mode 1N, when the unit cell 1n reaches the charge completion voltage, the voltage detector 5 connected to the unit cell 1n generates the charge completion detection signal S1. In response to the charging completion detection signal S1 corresponding to the unit cell 1n, the control unit 3 supplies a charging stop signal S2 to the battery control circuit 1nC, changes the bypass switch C1n from off to on, and turns on the charging control switch A1n. To turn off. At the same time, in the mode 1N, when all the single cells 1a, 1b,..., 1n of the battery circuit array 100 have reached the charge completion voltage, the control unit 3 performs the charge stop signal S 2 for the battery control circuit 1nC. Immediately after generating the column control signal S3, the column control signal S3 for the column control circuit 10C is generated, and the column control signal S3 changes the column control switch A10 from on to off. By turning off the column control switch A10, all the bypass switches C11, C12,..., C1n of the battery circuit row 100 are changed from on to off.

When the column control switch A10 is turned off, the charging current of the constant current value I for the battery circuit row 100 is interrupted by the column control switch A10, so that all the bypass switches C11, C12,. -When C1n is turned on, the inconvenience that the charging current of the constant current value I with respect to the remaining battery circuit rows 200,. Further, the increase in the constant current value I for the other battery circuit arrays 200, 300,..., N00 accompanying the interruption of the charging current I for the battery circuit array 100 is caused by the battery circuit arrays 200, 300. ,..., N00 are suppressed by the current control circuit 6 of the column control circuits 20C, 30C,..., N0C, and a predetermined constant current value I is maintained.

In the mode 1N, when the single cells 2a, 2b,..., 2n in the battery circuit array 200 sequentially reach the charging completion voltage of 4.1 volts, the same operation as described above is performed.

All the cells 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., (n-1) in the battery circuit array 100, 200, ..., (n-1) 00 ) A, (n−1) b,..., (N−1) n reaches a charging completion voltage of 4.1 volts, the unit cell na in the battery circuit array n00 has a charging completion voltage of 4.1 volts. This state is referred to as mode NA. In this mode NA, when the unit cell na reaches the charging completion voltage, the voltage detector 5 connected to the unit cell na generates the charging completion detection signal S1. In response to the charging completion detection signal S1 corresponding to the unit cell na, the control unit 3 supplies a charging stop signal S2 to the battery control circuit n1C, changes the bypass switch Cn1 from off to on, and turns on the charging control switch An1. To turn off.

In this mode NA, in the battery circuit array n00, the unit cell na and the charge control switch An1 are short-circuited by the bypass switch Cn1, and the charging current of the constant current value I bypasses the unit cell na, and other unit cells nb,. • nn is supplied and charging of these cells continues. The unit cell na and the charging control switch An1 are short-circuited by the bypass switch Cn1, but the constant current value I flowing through the battery circuit array n00 is suppressed from rising by the current limiting circuit 6 of the column control circuit n0C, and the constant current value I Is maintained.

In mode NA, it is assumed that the cell nb has reached the charging completion voltage of 4.1 volts, and this state is referred to as mode NB. In this mode NB, when the cell nb reaches the charge completion voltage, the voltage detector 5 connected to the cell nb generates the charge completion detection signal S1. In response to the charge completion detection signal S1 corresponding to the single cell nb, the control unit 3 supplies a charge stop signal S2 to the battery control circuit n2C, changes the bypass switch Cn2 from off to on, and turns on the charge control switch An2. To turn off.

In the mode NB, in the battery circuit array n00, the single cells na and nb and the charge control switches An1 and An2 are short-circuited by the bypass switches Cn1 and Cn2, and the charging current of the constant current value I bypasses the single cells na and nb. , Nn, and the charging of these cells continues. Even if the cell nb and the charging control switch An2 are short-circuited by the bypass switch Cn2, the constant current value I flowing through the battery circuit column n00 is suppressed from rising by the current limiting circuit 6 of the column control circuit n0C and reaches the mode NN. Until this time, the constant current value I is maintained, and the unit cell that has not been charged by the constant current value I is charged with constant current.

, N (n−1) in the battery circuit array n00 all reach the charging completion voltage of 4.1 volts, and the corresponding bypass switches Cn1, Cn2,..., Cn (n -1) is turned on, and the corresponding charging control switches An1, An2,..., An (n-1) are turned off, the cell nn reaches the charging completion voltage of 4.1 volts. This state is referred to as mode NN. In this mode NN, the overall terminal voltage of the battery circuit array n00 also reaches n × 4.1 volts. In this mode NN, when the cell nn reaches the charge completion voltage, the voltage detector 5 connected to the cell nn generates the charge completion detection signal S1. In response to the charging completion detection signal S1 corresponding to the unit cell nn, the control unit 3 supplies a charging stop signal S2 to the battery control circuit nnC, changes the bypass switch Cnn from off to on, and turns on the charging control switch Ann. To turn off. At the same time, in the mode NN, when all the cells 1a, 1b,..., 1n of the battery circuit array n00 have reached the charge completion voltage, the control unit 3 performs the charge stop signal S 2 for the battery control circuit nnC. Immediately after generating, a column control signal S3 for the column control circuit n0C is generated, and the column control signal An switches the column control switch An0 from on to off. By turning off the column control switch An0, all the bypass switches Cn1, Cn2,..., Cnn of the battery circuit column n00 are changed from on to off.

When the column control switch An0 is turned off, the charging current of the constant current value I for the battery circuit row n00 is cut off by the column control switch An0, and the charging current for each battery circuit row 100, 200,. All are shut off and charging for all the cells is completed.

After all the cells 1a, 1b,..., 1n, 2a, 2b,..., 2n, na, nb,. Is used for supplying power to the DC load 4 while being floatingly charged by the charger 2. The discharge from each unit cell to the DC load 4 is performed for all the diodes B10, B11, B12,..., B1n, B20, B21, B22,..., B2n, ..., Bn0, Bn1, Bn2,. .. Performed through Bnn. The single cells whose voltage has dropped due to this discharge are diodes B10, B11, B12,..., B1n, B20, B21, B22,..., B2n, ..., Bn0, Bn1, Bn2,. It is charged through Bnn.

As described above, in the first embodiment, each cell 1a, 1b, ..., 1n, 2a, 2b, ..., 2n, ..., na, nb, ..., nn is completely charged. When the voltage is reached, it is bypassed by the corresponding bypass switch C11, C12, ..., C1n, C21, C22, ..., C2n, ..., Cn1, Cn2, ..., Cnn. It is possible to eliminate the inconvenience that a single cell that has quickly reached the charge completion voltage is overcharged.

In addition, since each of the battery circuit rows 100, 200,..., N00 is provided with the column control switches A10, A20,..., An0 and the current limiting circuit 6, each cell has a corresponding bypass switch. When bypassed, it is possible to improve the disadvantage that the charging current to other cells not fully charged in the same battery circuit row is increased, and charging of all the cells in each battery circuit row can be improved. When completed, the disadvantage that the charging current of the battery circuit array including the single cells that have not been fully charged is reduced, and each single cell can be charged efficiently.

The charging / discharging circuit of the lithium ion secondary battery according to the present invention is applied to a mobile radio communication device such as a mobile phone and a cordless phone, a video camera, a notebook personal computer and the like.

FIG. 1 is an electric circuit diagram showing Embodiment 1 of a charge / discharge circuit of a lithium ion secondary battery according to the present invention. FIG. 2 is a chart for explaining a charging operation according to the first embodiment.

Explanation of symbols

100, 200,..., N00: battery circuit array,
1a, 1b, 1n, 2a, 2b, 2n, na, nb, nn: lithium ion secondary battery,
2: charger, 3: control unit, 4: DC load, 5: voltage detector, 6: current limiting circuit,
10C, 20C,..., N0C: column control circuit,
A10, A20, An0: column control switch,
11C, 12C, 1nC, 21C, 22C, 2nC, n1C, n2C, nnC: battery control circuit,
A11, A12, A1n, A21, A22, A2n, An1, An2, Ann: Charge control switch,
C11, C12, C1n, C21, C22, C2n, Cn1, Cn2, Cnn: Bypass switches.

Claims (5)

  A charging / discharging circuit of a lithium ion secondary battery comprising a plurality of battery circuit arrays connected in parallel to each other, each of these battery circuit arrays including a plurality of lithium ion secondary batteries connected in series with each other. In addition, a bypass switch is connected to each lithium ion secondary battery in each battery circuit row, and when each of the lithium ion secondary batteries reaches a charging completion voltage, a charging current is bypassed by the corresponding bypass switch. And a current limiting circuit and a column control switch are connected in series with each of the lithium ion secondary batteries included in each of the battery circuit arrays, and all of the battery circuit arrays include all of the battery circuit arrays. When the lithium ion secondary battery reaches the charging completion voltage, the column control switch of the battery circuit column is turned off. Charging and discharging circuit of the lithium ion secondary battery, characterized.   The charge / discharge circuit for a lithium ion secondary battery according to claim 1, wherein a discharge diode is connected in parallel to the current limiting circuit and the column control switch in each of the battery circuit columns. Charge / discharge circuit for lithium ion secondary battery.   2. The charging / discharging circuit for a lithium ion secondary battery according to claim 1, wherein each of the lithium ion secondary batteries is provided with a voltage detector for detecting the charging voltage, and each of the voltage detectors is A charging / discharging circuit for a lithium ion secondary battery, wherein the charging / discharging circuit is connected to a control unit and the control unit controls the bypass switches and the column control switches.   The charge / discharge circuit for a lithium ion secondary battery according to claim 3, wherein a charge control switch controlled by the control unit is connected in series to each of the lithium ion secondary batteries, and each bypass switch is A charging / discharging circuit for a lithium ion secondary battery, wherein each of the corresponding lithium ion secondary batteries and the charge control switch are connected in parallel. A charge-discharge circuit according to claim 4 lithium ion secondary battery, wherein KakuTakashi charge control switch also, the same charging and discharging circuit of the lithium ion secondary battery, characterized in that parallel to the discharge diode is connected .

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