JP6559463B2 - Charge control device, charge control method, and battery pack - Google Patents

Description

  The present embodiment relates to a charge control device, a charge control method, and a battery pack.

  Conventionally, for example, a secondary battery such as a lithium ion battery is charged until the charging voltage reaches a predetermined charging completion voltage (full charging voltage). The charge completion voltage is an upper limit value of the charge voltage that can be safely charged, and charging (overcharge) with a voltage exceeding the charge end voltage causes deterioration of the battery performance. Whether or not the charging voltage has reached a predetermined charging completion voltage is controlled by monitoring the potential difference between the positive and negative electrodes of the battery.

  On the other hand, as a battery electrode, a lithium ion battery including a reference electrode in addition to a positive electrode and a negative electrode is also disclosed.

Japanese Patent Laid-Open No. 11-67280 JP 2008-108435 A

  When a battery having deteriorated on the positive electrode side or the negative electrode side is charged, a high voltage is applied to the non-deteriorated electrode side, and the non-deteriorated electrode is also deteriorated.

  This embodiment can accurately detect deterioration on the positive electrode side or the negative electrode side during charging of the battery, and adjusts the charge completion voltage when deterioration on the positive electrode side or the negative electrode side is detected. The present invention provides a charge control device, a charge control method, and a battery pack that can reduce damage to a positive electrode and a negative electrode due to overcharging and extend battery life.

  According to one aspect of the present embodiment, there is provided a charge control device that supplies power supplied from an input power source to a battery as charging power and charges the battery until the battery voltage reaches a charge completion voltage. A positive voltage monitor for detecting a potential difference between the positive electrode and the reference electrode as a positive voltage, and a negative electrode of the battery and the reference electrode. And a negative voltage monitor that detects a potential difference between the negative electrode and the reference electrode as a negative voltage, the positive voltage detected by the positive voltage monitor, and the negative voltage detected by the negative voltage monitor. Based on the above, it is determined whether the potential of either one or both of the positive electrode and the negative electrode is lower than the assumed potential, and either one of the positive electrode or the negative electrode If properly is that both potential detects the lower than expected voltage, the charging control device is provided and a charging control unit for adjusting the value of the charging completion voltage automatically.

  According to another aspect of the present embodiment, the battery and charge control for supplying the power supplied from the input power source to the battery as charging power and charging the battery until the battery voltage reaches the charge completion voltage. A positive electrode voltage monitor connected to a positive electrode and a reference electrode of the battery and detecting a potential difference between the positive electrode and the reference electrode as a positive electrode voltage; a negative electrode of the battery; and the reference electrode A negative voltage monitor that detects a potential difference between the negative electrode and the reference electrode as a negative voltage, and the positive voltage detected by the positive voltage monitor and the negative voltage monitor detected by the negative voltage monitor Based on the negative electrode side voltage, it is determined whether the potential of one or both of the positive electrode and the negative electrode is lower than an assumed potential, and the positive electrode and the negative A battery pack is provided that includes a charge control unit that includes a charge control unit that automatically adjusts the value of the charge completion voltage when detecting that one or both of the potentials is lower than the assumed potential. .

  According to another aspect of the present embodiment, the power supplied from the input power supply is supplied to the battery as charging power, and is executed by the charging control device that charges the battery until the battery voltage reaches the charging completion voltage. The battery charge control method, wherein a positive voltage monitor connected to a positive electrode and a reference electrode of the battery detects a potential difference between the positive electrode and the reference electrode as a positive voltage; A step of detecting a potential difference between the negative electrode and the reference electrode as a negative voltage by a negative voltage monitor connected to a negative electrode of the battery and the reference electrode, and the positive voltage monitor detected by the charge controller Based on the positive side voltage and the negative side voltage detected by the negative side voltage monitor, either the positive side or the negative side may be used. Determines whether both potentials are lower than the assumed potential, and if it detects that the potential of either one or both of the positive electrode and the negative electrode is lower than the assumed potential, it automatically sets the value of the charging completion voltage. A charging control method is provided.

  According to the present embodiment, it is possible to accurately detect deterioration on the positive electrode side or the negative electrode side during charging of the battery, and adjust the charge completion voltage when the deterioration on the positive electrode side or the negative electrode side is detected. Thus, it is possible to provide a charge control device, a charge control method, and a battery pack that can reduce damage to the positive electrode and the negative electrode due to overcharge and extend the battery life.

The typical block block diagram of the charge control apparatus which concerns on a comparative example. Explanatory drawing which illustrates typically the charging reaction inside a lithium ion battery, and transition of a battery voltage. Explanatory drawing which shows an example when it charges in the state which the negative electrode side of the battery deteriorated in the charge control apparatus which concerns on a comparative example. Explanatory drawing which shows an example when it charged in the state which the negative electrode side of the battery deteriorated in the charge control apparatus which concerns on embodiment. The typical block block diagram of the battery pack provided with the charge control apparatus (control IC) which concerns on embodiment. The typical block block diagram of the battery pack provided with the charge control apparatus (control IC) which concerns on the modification 1 of embodiment. The typical block block diagram of the battery pack provided with the charge control apparatus (control IC) which concerns on the modification 2 of embodiment. The typical block block diagram of the battery pack provided with the charge control apparatus (control IC) which concerns on the modification 3 of embodiment. The schematic flowchart which shows an example of the charge control method of the battery by the charge control apparatus which concerns on a comparative example. Schematic which shows an example of the charge characteristic in the charge control method of the battery illustrated in FIG. The schematic flowchart which shows an example of the charge control method of the battery by the charge control apparatus which concerns on embodiment. FIG. 12 is a schematic diagram illustrating an example of charge characteristics in the battery charge control method illustrated in FIG. 11, (a) a diagram illustrating the potential of the positive electrode and the negative electrode on the basis of GND, and (b) a potential of the positive electrode and the negative electrode on the reference electrode reference. FIG.

  Next, embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In addition, the embodiment described below exemplifies an apparatus and method for embodying the technical idea, and does not specify the material, shape, structure, arrangement, etc. of the component parts as follows. . This embodiment can be modified in various ways within the scope of the claims.

[Comparative example]
A schematic block configuration of the charge control device according to the comparative example is expressed as shown in FIG. FIG. 2 schematically illustrates the charging reaction inside the lithium-ion battery and the transition of the battery voltage. FIG. 3 illustrates the charging control device according to the comparative example in a state where the negative electrode side of the battery is deteriorated. An example is shown schematically.

  The charge control device 10 according to the comparative example is a charge control device that supplies power supplied from the input power source 200 to the positive electrode 21 of the battery 20 as charging power, and includes a charge control unit 11, a current monitor 12, and a positive electrode. A negative electrode voltage monitor 13, a charging current detection resistor 16, and a control transistor 19 are provided.

  An input power supply 200 is connected to the source of the control transistor 19, the gate of the control transistor 19 is connected to the charge control unit 11, and the drain of the control transistor 19 is connected to the charge current detection resistor 16.

  The current monitor 12 is connected to both ends of the charging current detection resistor 16, detects the current I flowing through the positive electrode 21 of the battery 20 through the charging current detection resistor 16, and sends the detected current value I to the charging control unit 11. A GND terminal 30 is connected to the negative electrode 22 side of the battery 20, and the GND terminal 30 is connected to the ground voltage.

  The positive-negative voltage monitor 13 is connected to both ends of the positive electrode 21 side and the negative electrode 22 side of the battery 20, and sends the total voltage at both ends of the positive electrode 21 and the negative electrode 22 to the charge control unit 11 as the battery voltage VB (charge voltage). .

  The charge control unit 11 controls the control transistor 19 so that the charge current I or the charge voltage becomes a desired value from the charge current value detected by the current monitor 12 and the battery voltage VB detected by the positive-negative voltage monitor 13. Controls the voltage supplied to the gate.

Since the battery electrode of the lithium ion battery 20 used in the charge control device 10 according to the comparative example has a two-terminal configuration of the positive electrode 21 (+) and the negative electrode 22 (−), both terminals of the positive electrode 21 and the negative electrode 22 are connected to both ends. The battery voltage VB is determined from the total voltage. More specifically, as shown in FIG. 2, the lithium ion battery 20 has a mechanism in which electricity flows (charges and discharges) when lithium ions Li ⁺ move between the positive electrode and the negative electrode inside the battery. At the time of charging, as shown in FIG. 2, lithium ions Li ⁺ escape from the crystal structure of the positive electrode 21 into the electrolytic solution and are inserted into the crystal layer side of the negative electrode 22. As the charging proceeds, the potential on the positive electrode 21 side and the potential on the negative electrode 22 side increase. For example, the sum of the potential Vp1 on the positive electrode 21 side and the potential Vn1 on the negative electrode 22 side at time t5 becomes the battery potential VB1. .

  As shown in FIG. 3, for example, when charging the battery 20 in which the potential Vn2 that can be output from the negative electrode 22 is reduced due to the deterioration of the negative electrode 22, the positive electrode that has not deteriorated is charged in order to charge to the predetermined charge completion voltage VB2. A voltage that is higher than the potential 21 (the potential Vp2 that can be output) by the potential difference ΔV is applied, and even the positive electrode 21 that has not deteriorated is deteriorated. Even if the positive electrode 21 or the negative electrode 22 of the battery 20 is deteriorated, if the means for detecting the deterioration and the control means corresponding to the deterioration are not provided, the life of the battery 20 is reduced.

[Embodiment]
(Charge control device and battery pack equipped with the charge control device)
A schematic block configuration of the battery pack 100 including the charge control device 10 (control IC) according to the embodiment is expressed as shown in FIG. FIG. 4 schematically shows an example when charging is performed in a state where the negative electrode 22 side of the battery 20 is deteriorated in the charging control apparatus 10 according to the embodiment.

  In the embodiment, in the charge control device 10 using the battery 20 having the reference electrode 23 which is the third electrode in addition to the normal positive electrode 21 and the negative electrode 22, it is obtained by monitoring between the positive electrode 21 and the negative electrode 22. In addition to the battery voltage VB, the voltage between the positive electrode 21 and the reference electrode 23 and the voltage between the negative electrode 22 and the reference electrode 23 are monitored. From the voltage values obtained by monitoring between the positive electrode 21 and the reference electrode 23 and between the negative electrode 22 and the reference electrode 23, from the voltage values Vp3 and Vn3 that can be originally charged by the deterioration on the positive electrode 21 side or the negative electrode 22 side. When the difference is observed, the charge completion voltage is lowered by the difference in potential difference ΔV (adjusted to the charge completion voltage VB3). Thereby, damage to both the positive electrode 21 and the negative electrode 22 can be reduced, and as a result, the battery life can be extended.

  The battery pack 100 according to the embodiment includes a battery 20 and a charge control device 10 as shown in FIG.

  As illustrated in FIG. 5, the charging control apparatus 10 according to the embodiment supplies the power supplied from the input power source 200 to the positive electrode 21 of the battery 20 as charging power, and the battery voltage reaches the charging completion voltage. A charge control device of a linear type that charges the battery 20 until a charge control unit 11, a current monitor 12, a positive-negative voltage monitor 13, a positive-side voltage monitor 14, and a negative-side voltage monitor 15 The charging current detection resistor 16 and the control transistor 19 are provided.

  An input power supply 200 is connected to the source of the control transistor 19, the gate is connected to the charge control unit 11, and the drain is connected to the charge current detection resistor 16.

  The current monitor 12 is connected to both ends of the charging current detection resistor 16, detects a current (charging current) I flowing through the positive electrode 21 of the battery 20 through the charging current detection resistor 16, and uses the detected current value I as a charging control unit. 11 A GND terminal 30 is connected to the negative electrode 22 side of the battery 20, and the GND terminal 30 is connected to the ground voltage.

  The positive-negative voltage monitor 13 is directly connected to the positive electrode 21 and the negative electrode 22 of the battery 20 and detects the battery voltage VB (charging voltage) from the total voltage across the positive electrode 21 and the negative electrode 22 terminals. The battery voltage VB is sent to the charge control unit 11.

  The positive electrode side voltage monitor 14 is connected to the positive electrode 21 and the reference electrode 23 of the battery 20, and detects the potential difference between the positive electrode 21 and the reference electrode 23 as a voltage on the positive electrode 21 side (positive electrode side voltage). The side voltage is sent to the charging control unit 11.

  The negative electrode side voltage monitor 15 is connected to the negative electrode 22 and the reference electrode 23 of the battery 20 and detects a potential difference between the negative electrode 22 and the reference electrode 23 as a voltage on the negative electrode 22 side (negative electrode side voltage). The side voltage is sent to the charging control unit 11.

  The charging control unit 11 includes a charging current value detected by the current monitor 12, a battery voltage VB detected by the positive / negative voltage monitor 13, a positive voltage detected by the positive voltage monitor 14, and a negative voltage monitor 15. The voltage supplied to the gate of the control transistor 19 is linearly controlled so that the charging current I or the charging voltage becomes a desired value based on the negative side voltage detected by, and the resistance value of the charging current detection resistor 16 is Change (linear method).

  At the same time, the charging control unit 11 determines whether either the positive electrode 21 or the negative electrode 22 during the charging operation based on the positive voltage detected by the positive voltage monitor 14 and the negative voltage detected by the negative voltage monitor 15. It is determined whether one or both of the potentials is lower than the assumed potential stored in advance in the memory 17 (potential difference ΔV in the example shown in FIG. 4), and the potential of one or both of the positive electrode 21 and the negative electrode 22 is When it is detected that the voltage is lower than the assumed potential, the charge completion voltage is automatically lowered by a potential difference ΔV from the assumed potential. In other words, for example, when the negative electrode 22 side deteriorates, the charging control unit 11 does not add the potential difference ΔV to the positive electrode 21 that has not deteriorated as in the comparative example, but instead adds the potential difference ΔV to the voltage value VB3. Adjust the charge completion voltage. As a result, charging can be performed within the range of the potential Vp3 value that can be output originally by the positive electrode 21 and within the range of the potential Vn3 value that can be output after the negative electrode 22 is deteriorated. Deterioration can be prevented.

  Moreover, since the charge control apparatus 10 according to the embodiment monitors the voltages on both sides between the positive electrode 21 and the reference electrode 23 and between the negative electrode 22 and the reference electrode 23, the abnormal state of the battery 20 is detected more accurately. By automatically adjusting the charging completion voltage, electrode deterioration and the like can be prevented, and the battery 20 can be used in a longer cycle.

  In the charging control apparatus 10 according to the embodiment, the battery voltage VB is detected by the positive-negative voltage monitor 13 directly connected to the positive electrode 21 and the negative electrode 22 of the battery 20. The battery voltage VB may be calculated from the total value of the positive voltage and negative voltage detected by the voltage monitor 15.

(Modification 1)
As illustrated in FIG. 6, the charging control apparatus 10 according to the first modification of the embodiment supplies the power supplied from the input power source 200 to the positive electrode 21 of the battery 20 as charging power, and the battery voltage is charged. This is a switching-type charge control device that charges the battery 20 until the completion voltage is reached.

  The charge control device 10 according to the first modification includes a charge control unit 11, a current monitor 12, a positive-negative voltage monitor 13, a positive-side voltage monitor 14, a negative-side voltage monitor 15, and a charging current detection resistor. 16, a coil 27, a diode 18, and a control transistor 19.

  An input power supply 200 is connected to the source of the control transistor 19, the gate is connected to the charge control unit 11, and the drain is connected to the charge current detection resistor 16. The control transistor 19 also functions as a switching transistor.

  One end of the coil 27 is connected to the drain of the control transistor 19, and the other end of the coil 27 is connected to the charging current detection resistor 16. A diode 18 is connected between the drain of the control transistor 19 and the ground potential. A rectifier circuit is formed from the coil 27 and the diode 18. Instead of the diode 18, an FET (Field Effect Transistor) can be used.

  Since the configuration of each part of the battery pack 100 including the charge control device 10 according to the modification 1 other than the above is the same as the configuration of each part of the embodiment illustrated in FIG. 5, detailed description thereof is omitted.

  The charging control unit 11 includes a charging current value detected by the current monitor 12, a battery voltage VB detected by the positive / negative voltage monitor 13, a positive voltage detected by the positive voltage monitor 14, and a negative voltage monitor 15. The control transistor 19 is alternately switched by controlling the duty ratio of the pulse voltage supplied to the gate of the control transistor 19 so that the charge current I or the charge voltage becomes a desired value based on the negative side voltage detected by the The resistance value of the charging current detection resistor 16 is changed (switching method).

  At the same time, the charging control unit 11 determines whether either the positive electrode 21 or the negative electrode 22 during the charging operation based on the positive voltage detected by the positive voltage monitor 14 and the negative voltage detected by the negative voltage monitor 15. It is determined whether one or both of the potentials is lower than the assumed potential stored in advance in the memory 17 (potential difference ΔV in the example shown in FIG. 4), and the potential of one or both of the positive electrode 21 and the negative electrode 22 is When it is detected that the voltage is lower than the assumed potential, the charge completion voltage is automatically lowered by a potential difference ΔV from the assumed potential.

(Modification 2)
As shown in FIG. 7, the battery pack 100 including the charge control device 10 according to the second modification of the embodiment includes N batteries 20-1 (N is an integer of 2 or more) arranged in series. 20-2... 20-N and the charging control device 10 are provided.

  The charging control apparatus 10 according to the second modification supplies the power supplied from the input power supply 200 to the positive electrode 21 of the battery 20 as charging power, and linearly charges the battery 20 until the battery voltage reaches the charging completion voltage. Although the charging control device is a switching method, switching charging control can be applied instead of the linear method.

  As shown in FIG. 7, the charge control device 10 according to the second modification includes a charge control unit 11, a current monitor 12, a positive / negative voltage monitor 13, a positive voltage monitor 14, and a negative voltage monitor 15. And a charging current detection resistor 16, a control transistor 19, and a switch group 40.

  The switch group 40 is connected to the positive electrode 21, the negative electrode 22, and the reference electrode 23 of each of the plurality of batteries 20-1, 20-2,. .., 20-N are connected to the positive voltage monitor 14 and the negative voltage monitor 15 in a switchable manner.

  The positive voltage monitor 14 is connected to at least one of the plurality of batteries 20-1, 20-2,..., 20-N by the switch group 40 so as to be switchable, and the positive electrode 21 of the connected battery. And the reference electrode 23 is detected as a positive side voltage of the battery, and the detected positive side voltage is sent to the charge control unit 11.

  Similarly, the negative voltage monitor 15 is switchably connected to at least one of the plurality of batteries 20-1, 20-2,... The potential difference between the negative electrode 22 and the reference electrode 23 is detected as the negative electrode side voltage of the battery, and the detected negative electrode side voltage is sent to the charge control unit 11.

  Since the configuration of each part of the battery pack 100 including the charge control device 10 according to the second modification other than the above is the same as the configuration of each part of the embodiment illustrated in FIG. 5, detailed description thereof is omitted.

  The charging control unit 11 includes a charging current value detected by the current monitor 12, a battery voltage VB detected by the positive / negative voltage monitor 13, a positive voltage detected by the positive voltage monitor 14, and a negative voltage monitor 15. The voltage supplied to the gate of the control transistor 19 is linearly controlled so that the charging current I or the charging voltage becomes a desired value based on the negative side voltage detected by, and the resistance value of the charging current detection resistor 16 is Change.

  At the same time, the charging control unit 11 determines whether either the positive electrode 21 or the negative electrode 22 during the charging operation based on the positive voltage detected by the positive voltage monitor 14 and the negative voltage detected by the negative voltage monitor 15. It is determined whether one or both of the potentials is lower than the assumed potential stored in advance in the memory 17 (potential difference ΔV in the example shown in FIG. 4), and the potential of one or both of the positive electrode 21 and the negative electrode 22 is When it is detected that the voltage is lower than the assumed potential, the charge completion voltage is automatically lowered by a potential difference ΔV from the assumed potential.

(Modification 3)
As shown in FIG. 8, the battery pack 100 including the charge control device 10 according to the third modification of the embodiment includes two batteries 20-1 and 20-2 arranged in series, and the charge control device 10. With. In the third modification, an example including two batteries 20-1 and 20-2 has been shown for ease of explanation. However, as in the second modification, N (where N is 2 or more). (Integer) batteries 20-1, 20-2,..., 20-N can also be provided.

  The charging control apparatus 10 according to the modification 3 supplies the power supplied from the input power source 200 to the positive electrode 21 of the battery 20 as charging power, and charges the battery 20 until the battery voltage reaches the charging completion voltage. Although the charging control device is a switching method, switching charging control can be applied instead of the linear method.

  As shown in FIG. 7, the charge control device 10 according to the third modification includes a charge control unit 11, a current monitor 12, a positive-negative voltage monitor 13, a positive-side voltage monitor 14, and a negative-side voltage monitor 15. And a charging current detection resistor 16, a control transistor 19, and a switch group 40 including switches 41, 42, and 43.

  The switch 41 performs a switching operation so that the negative voltage monitor 15 is connected to one of the negative electrode 22 of the battery 20-1 and the negative electrode 22 of the battery 20-2.

  The switch 42 performs a switching operation so that the positive voltage monitor 14 and the negative voltage monitor 15 are connected to any one of the reference electrode 23 of the battery 20-1 and the reference electrode 23 of the battery 20-2. Do.

  The switch 43 performs a switching operation so that the positive voltage monitor 14 is connected to any one of the positive electrode 21 of the battery 20-1 and the positive electrode 21 of the battery 20-2.

  In the example shown in FIG. 8, the positive voltage monitor 14 is connected to the positive electrode 21 and the reference electrode 23 of the battery 20-1 via the switches 42 and 43, and the positive electrode 21 and the reference electrode 23 of the battery 20-1. Is detected as the positive side voltage of the battery, and the detected positive side voltage is sent to the charge control unit 11. The negative voltage monitor 15 is connected to the negative electrode 22 and the reference electrode 23 of the battery 20-1 via the switches 41 and 42, and the potential difference between the negative electrode 22 and the reference electrode 23 of the battery 20-1 is determined. The negative voltage of the battery is detected, and the detected negative voltage is sent to the charge controller 11.

  Since the configuration of each part of the battery pack 100 including the charge control device 10 according to the third modification other than the above is the same as the configuration of each part of the second modification illustrated in FIG. 7, detailed description thereof is omitted.

  The charging control unit 11 includes a charging current value detected by the current monitor 12, a battery voltage VB detected by the positive / negative voltage monitor 13, a positive voltage detected by the positive voltage monitor 14, and a negative voltage monitor 15. The voltage supplied to the gate of the control transistor 19 is linearly controlled so that the charging current I or the charging voltage becomes a desired value based on the negative side voltage detected by, and the resistance value of the charging current detection resistor 16 is Change.

  At the same time, the charging control unit 11 determines whether either the positive electrode 21 or the negative electrode 22 during the charging operation based on the positive voltage detected by the positive voltage monitor 14 and the negative voltage detected by the negative voltage monitor 15. It is determined whether one or both of the potentials is lower than the assumed potential stored in advance in the memory 17 (potential difference ΔV in the example shown in FIG. 4), and the potential of one or both of the positive electrode 21 and the negative electrode 22 is When it is detected that the voltage is lower than the assumed potential, the charge completion voltage is automatically lowered by a potential difference ΔV from the assumed potential.

(Charging control method according to comparative example)
FIG. 9 shows an example of a charge control method for the battery 20 by the charge control device 10 according to the comparative example. FIG. 10 shows an example of charging characteristics in the battery charging control method illustrated in FIG.

  First, in step S <b> 101, the charging control device 10 detects that the battery 20 is mounted, and further starts charging control when detecting power supply from the input power source 200.

  Next, in step S102, the charging control apparatus 10 starts trickle charging that continuously applies a minute current (trickle charging current R5) to the depleted battery 20 (period PT). A specific value of the trickle charging current R5 is, for example, about 20 mA to 300 mA.

  Next, in step S103, the charging control apparatus 10 determines whether or not the battery voltage VB detected by the positive / negative voltage monitor 13 has reached a predetermined preliminary charging start voltage R2. A specific value of the precharge start voltage R2 is, for example, about 2.5V to 3.6V.

  If the result of determination in step S103 is that the battery voltage VB has not reached the precharge start voltage R2, the process returns to step S102 to continue trickle charging.

  As a result of the determination in step S103, when the battery voltage VB reaches the precharge start voltage R2 (time t1 in the example of FIG. 10), the process proceeds to step S104, and the charge control device 10 keeps the system voltage VS constant, Pre-charging with the pre-charging current R6 is started (period PA). A specific value of the precharge current R6 is, for example, about 100 mA to 2000 mA.

  Next, in step S105, the charging control apparatus 10 determines whether or not the battery voltage VB has reached a predetermined rapid charging start voltage R3. A specific value of the quick charge start voltage R3 is, for example, about 3.0V to 3.6V.

  As a result of the determination in step S105, when the battery voltage VB has not reached the quick charge start voltage R3, the process returns to step S104 to continue the preliminary charge.

  As a result of the determination in step S105, when the battery voltage VB has reached the quick charge start voltage R3 (time t2 in the example of FIG. 10), the process proceeds to step S106, and the charge control device 10 operates the control transistor 19, Rapid charging (constant current) by the rapid charging current R7 is started (period PH). A specific value of the rapid charging current R7 is, for example, about 500 mA to 5000 mA.

  Next, in step S107, the charging control apparatus 10 determines whether or not the battery voltage VB has reached a predetermined charging completion voltage R1. A specific value of the charging completion voltage R1 is, for example, about 3.73V to 4.35V.

  As a result of the determination in step S107, when the battery voltage VB has not reached the charging completion voltage R1, the process returns to step S106 and the rapid charging (constant current) is continued.

  As a result of the determination in step S107, when the battery voltage VB reaches the charge completion voltage R1 (time t3 in the example of FIG. 10), the process proceeds to step S108, and the charge control device 10 keeps the charge voltage constant (recharge). Voltage R4) and rapid charging (constant voltage) for gradually decreasing the charging current CB is started (period PH). A specific value of the recharge voltage R4 is, for example, about -0.05V to 0.35V.

  Next, in step S109, the charging control apparatus 10 determines whether or not the charging current CB detected by the current monitor 12 has decreased to a predetermined charging end current R8. A specific value of the charge termination current R8 is, for example, about 50 mA to 2000 mA.

  As a result of the determination in step S109, when the charging current CB has not decreased to the charging end current R8, the process returns to step S108 and the rapid charging (constant voltage) is continued.

  As a result of the determination in step S109, when the charging current CB decreases to the charging end current R8 (time t4 in the example of FIG. 10), the process proceeds to step S110, and the charging control device 10 stops the charging process (period PS).

  As described above, in the charge control method according to the comparative example, when the battery voltage VB reaches the charge completion voltage (full charge voltage) R1 in the rapid charge, the rapid charge (constant current) is completed and the rapid charge (constant voltage). Has moved to.

(Charge control method according to the embodiment)
FIG. 11 shows an example of a charging control method for the battery 20 by the charging control device 10 according to the embodiment. FIG. 12 shows an example of charge characteristics in the battery charge control method illustrated in FIG.

  In FIG. 11, steps S101 to S106 are the same as the processes of steps S101 to S106 in the comparative example illustrated in FIG.

  When rapid charging (constant current) is started in step S106 (time t2), next, in step S201, the charging control device 10 detects that the positive voltage detected by the positive voltage monitor 14 is lower than the assumed voltage. It is determined whether or not.

  As a result of the determination in step S201, when the positive side voltage is lower than the assumed voltage, the process proceeds to step S202, and the charge control device 10 automatically reduces the value of the charge completion voltage R1 by the potential difference ΔV from the assumed potential.

  If the result of determination in step S201 is that the positive voltage has not fallen below the assumed voltage, processing proceeds to step S203.

  In step S203, the charging control apparatus 10 determines whether or not the negative voltage detected by the negative voltage monitor 15 is lower than the assumed voltage.

  As a result of the determination in step S203, if the negative side voltage is lower than the assumed voltage, the process proceeds to step S204, and the charging control device 10 automatically reduces the value of the charging completion voltage R1 by the potential difference ΔV from the assumed potential.

  As a result of the determination in step S203, when the negative side voltage is not lower than the assumed voltage, the process proceeds to step S107.

  Next, in step S107, the charging control apparatus 10 determines whether or not the battery voltage VB has reached the charging completion voltage R1. Note that the charge completion voltage R1 used for the determination in this case may be reduced in step S202 or S204, and in this case, the determination process is performed using the reduced charge completion voltage R1. Is called.

  Thereafter, processes similar to those in steps S107 to S110 in the comparative example illustrated in FIG. 9 are executed in steps S107 to S110.

  In the flowchart of FIG. 11, an example in which the process related to the positive side voltage (steps S201 and 202) is executed before the process related to the negative side voltage (steps S203 and 204) is shown. Steps S203 and 204) may be executed prior to the processing relating to the positive side voltage (steps S201 and 202), or both may be executed simultaneously.

  A further specific example (charge profile) of the process related to the positive side voltage (steps S201 and 202) and the process related to the negative side voltage (steps S203 and 204) will be described with reference to FIG. 12A shows the potential of the positive electrode and the negative electrode on the basis of GND, and FIG. 12B shows the potential of the positive electrode and the negative electrode (battery voltage VB4) on the basis of the reference electrode.

  When the battery voltage VB reaches the rapid charge start voltage R3 at time t2, rapid charge (constant current) is started. FIG. 12A shows that the battery voltage VB increases as the rapid charge (constant current) progresses. FIG. 12B shows the positive electrode 21 as the rapid charge (constant current) progresses. -It shows that the potential difference between the negative electrodes 22 increases.

  In the charge control method according to the embodiment, the potentials of the positive electrode 21 and the negative electrode 22 are measured using the reference electrode 23 as a reference, and compared with an assumed voltage value assumed in advance. In FIG. 12B, the assumed voltage value of the positive electrode 21 is indicated by p 1 · p 2 ···· p 10, and the assumed voltage value of the negative electrode is indicated by n 1 · n 2 ···· n 10.

  In the example shown in FIG. 12B, it is assumed that the battery voltage VB has increased as expected from the assumed voltage values p1 to p6 / n1 to n6. During this time, the process of step S106 → step S201 → step S203 → step S107 → step S106 is repeated. That is, the processes of steps S202 and S204 do not occur between the assumed voltage values p1 to p6 / n1 to n6.

  In FIG. 12B, when the negative voltage is lower than the assumed voltage value n7 by the potential difference ΔV1 (step S203), the charge control device 10 according to the embodiment sets the charge completion voltage R1 in step S204. Similarly, the potential difference ΔV1 is lowered. Furthermore, when the potential differences ΔV2 and ΔV3 increase at the assumed voltage values n8 and n9 (step S203), the charging completion voltage R1 is also decreased by the potential differences ΔV2 and ΔV3, respectively (step S204). As a result, when the battery 20 is charged to a voltage (VB5) lower in potential difference ΔV3 than the original charge completion voltage (VB6), the quick charge (constant current) is completed, and the rapid charge (constant voltage) is achieved. Transition.

  In the example of FIG. 12, the negative side voltage is lower than the assumed voltage value n1, n2,..., N10, but the potential of the positive electrode 21 is lower than the assumed voltage value p1, p2,. In this case, the charging completion voltage R1 is similarly lowered, or the charging is similarly completed when the potentials of both the positive electrode 21 and the negative electrode 22 are lower than the assumed voltage values p1, p2,..., P10 / n1, n2,. Reduce the voltage R1.

  As described above, according to the present embodiment and the first to third modifications thereof, the charging control device using the battery 20 having the reference electrode 23 as the third electrode in addition to the normal positive electrode 21 and the negative electrode 22. 10, in addition to the battery voltage VB obtained by monitoring between the positive electrode 21 and the negative electrode 22, between the positive electrode 21 and the reference electrode 23 and between the negative electrode 22 and the reference electrode 23 are monitored. The voltage value obtained by monitoring between the positive electrode 21 and the reference electrode 23 and between the negative electrode 22 and the reference electrode 23 is deviated from the voltage value that can be charged due to the deterioration on the positive electrode 21 side or the negative electrode 22 side. If it is observed, the charge completion voltage is lowered by the difference in potential ΔV. Thereby, damage to both the positive electrode 21 and the negative electrode 22 can be reduced, and as a result, the battery life can be extended.

According to the present embodiment and the first to third modifications thereof, it is possible to accurately detect deterioration on the positive electrode side or the negative electrode side while charging the battery, and detect deterioration on the positive electrode side or the negative electrode side, etc. By adjusting the charging completion voltage, it is possible to provide a charge control device, a charge control method, and a battery pack that can reduce damage to the positive electrode and the negative electrode due to overcharging and extend the battery life.
[Other embodiments]
As described above, the embodiment and the first to third modifications thereof have been described. However, it should be understood that the description and the drawings that form a part of this disclosure are illustrative and not limiting. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the embodiments and the first to third modifications thereof, the case of the constant current / constant voltage charging method has been described. However, charging methods other than the constant current / constant voltage charging method, for example, the two-stage constant voltage control charging method, two-stage The present invention can be similarly applied to a constant current charging method.

  Moreover, although the case of the lithium ion battery has been described in the embodiment and the modifications 1 to 1, the present invention can be similarly applied to a battery other than the lithium ion type, for example, a nickel metal hydride battery.

  As described above, various embodiments that are not described herein are included.

The charge control device, the charge control method, and the battery pack according to the present embodiment and the first to third modifications thereof are mobile devices (cell phones, PCs, tablet terminals, DSCs (Digital Still Cameras: Digital Still camera), DVC (Digital Video Camera)), electric bicycle, UPS (Uninterruptible Power Supply), household storage battery, EV (Electric Vehicle), electric tool, various power storage systems It can be applied to various application fields.

10 ... Charge control device (control IC)
DESCRIPTION OF SYMBOLS 11 ... Charge control part 12 ... Current monitor 13 ... Positive electrode-negative voltage monitor 14 ... Positive electrode side voltage monitor 15 ... Negative electrode side voltage monitor 16 ... Resistor 17 for charging current detection ... Memory 18 ... Diode 19 ... Control transistors 20, 20 -1, 20-2, 20-N ... Battery 21 ... Positive electrode 22 ... Negative electrode 23 ... Reference electrode 27 ... Coil 30 ... GND terminal 40 ... Switch group 40, 41, 43 ... Switch 100 ... Battery pack 200 ... Input power supply Li ⁺ ... Lithium ion I ... Current n1, n2, n6, n7, n8, n9, n10 ... Negative voltage assumption PA, PH, PT, PS ... Periods p1, p2, p6, p7, p8, p9, p10 ... Positive electrode Assumed voltage value R1 ... Charge completion voltage R2 ... Precharge start voltage R3 ... Quick charge start voltage R4 ... Recharge voltage R5 ... Trickle charge current R6 ... Precharge current R ... fast charge current R8 ... charging end current t1, t2, t3, t4, t5 ... time VB, VB2, VB3, VB4, VB5, VB6 ... Battery Voltage (potential)
Vp1, Vp2, Vp3: Positive side voltage (potential)
Vn1, Vn2, Vn3 ... Negative side voltage (potential)
ΔV, ΔV1, ΔV2, ΔV3 ... Potential difference

Claims (22)

A charging control device that supplies power supplied from an input power source to a battery as charging power and charges the battery until the battery voltage reaches a charging completion voltage,
A positive-side voltage monitor that is connected to a positive electrode and a reference electrode of the battery and detects a potential difference between the positive electrode and the reference electrode as a positive-side voltage;
A negative voltage monitor connected to the negative electrode of the battery and the reference electrode, and detecting a potential difference between the negative electrode and the reference electrode as a negative voltage;
Based on the positive voltage detected by the positive voltage monitor and the negative voltage detected by the negative voltage monitor, is the potential of one or both of the positive and negative electrodes lower than an assumed potential? A charge control unit that automatically adjusts the value of the charge completion voltage when it is determined that the potential of either one or both of the positive electrode and the negative electrode is lower than an assumed potential. A charge control device.   When the charge control unit detects that the potential of one or both of the positive electrode and the negative electrode is lower than the assumed potential, the charge control unit automatically sets the value of the charge completion voltage by an amount corresponding to the potential difference from the assumed potential. The charge control device according to claim 1, wherein the charge control device is pulled down. Each of the plurality of batteries arranged in series is connected to the positive electrode, the negative electrode, and the reference electrode, and at least one of the plurality of batteries is connected to the positive voltage monitor and the negative electrode side. A switch group that is switchably connected to the voltage monitor;
The positive voltage monitor detects the positive voltage of the battery connected by the switch group, and the negative voltage monitor detects the negative voltage of the battery connected by the switch group. The charge control device according to claim 1, wherein: The switch group includes:
A first switch for switchably connecting the positive voltage monitor to any one of the plurality of batteries;
A second switch for switchably connecting the positive voltage monitor and the negative voltage monitor to the reference electrode of any one of the plurality of batteries;
The charge control device according to claim 3 , further comprising: a third switch that switchesably connects the negative voltage monitor to any one of the plurality of batteries. A current monitor for detecting a charging current flowing in the positive electrode of the battery;
A positive-negative electrode voltage monitor that is connected to the positive electrode and the negative electrode of the battery and detects a battery voltage of the battery;
The charging control unit includes the charging current value detected by the current monitor, the battery voltage detected by the positive / negative voltage monitor, the positive voltage detected by the positive voltage monitor, and the negative side. The charge control device according to claim 1, wherein the charge current or the charge voltage is controlled to a desired value based on the negative voltage detected by the voltage monitor.   The charge control device according to claim 1, further comprising a memory that stores the assumed potential in advance.   The charge control device according to claim 1, wherein the battery is rapidly charged with a constant current until the battery voltage reaches the charge completion voltage.   The charging control device according to claim 7, wherein after the battery voltage reaches the charging completion voltage, the battery is rapidly charged with a constant voltage.   The charge control device according to claim 1, wherein the charge control device is a linear charge control device.   The charge control apparatus according to claim 1, wherein the charge control apparatus is a switching type charge control apparatus. Battery,
A charge control device that supplies power supplied from an input power source to a battery as charging power and charges the battery until the battery voltage reaches a charge completion voltage, and is connected to a positive electrode and a reference electrode of the battery And a positive voltage monitor for detecting a potential difference between the positive electrode and the reference electrode as a positive voltage, a negative electrode of the battery and the reference electrode, and a potential difference between the negative electrode and the reference electrode. Of the positive electrode and the negative electrode based on the negative voltage monitor that detects the negative voltage, the positive voltage detected by the positive voltage monitor, and the negative voltage detected by the negative voltage monitor. It is determined whether one or both of the potentials are lower than the assumed potential, and the potential of either one or both of the positive electrode and the negative electrode is equal to the assumed potential. If it is detected that is low, the battery pack characterized by comprising a charging control device and a charging control unit for automatically adjusting the value of the charging completion voltage.   When the charge control unit detects that the potential of one or both of the positive electrode and the negative electrode is lower than the assumed potential, the charge control unit automatically sets the value of the charge completion voltage by an amount corresponding to the potential difference from the assumed potential. The battery pack according to claim 11, wherein the battery pack is pulled down. The charge control device is connected to the positive electrode, the negative electrode, and the reference electrode of each of the plurality of batteries arranged in series, and at least one of the plurality of batteries is connected to the positive electrode side. A switch group that is switchably connected to the voltage monitor and the negative voltage monitor;
The positive voltage monitor detects the positive voltage of the battery connected by the switch group, and the negative voltage monitor detects the negative voltage of the battery connected by the switch group. The battery pack according to claim 11. The switch group includes:
A first switch for switchably connecting the positive voltage monitor to any one of the plurality of batteries;
A second switch for switchably connecting the positive voltage monitor and the negative voltage monitor to the reference electrode of any one of the plurality of batteries;
The battery pack according to claim 13 , further comprising: a third switch that switchesably connects the negative voltage monitor to any one of the plurality of batteries. The charge control device includes:
A current monitor for detecting a charging current flowing in the positive electrode of the battery;
A positive-negative electrode voltage monitor that is connected to the positive electrode and the negative electrode of the battery and detects a battery voltage of the battery;
The charging control unit includes the charging current value detected by the current monitor, the battery voltage detected by the positive / negative voltage monitor, the positive voltage detected by the positive voltage monitor, and the negative side. 12. The battery pack according to claim 11, wherein the charging current or the charging voltage is controlled to be a desired value based on the negative voltage detected by the voltage monitor.   The battery pack according to claim 11, wherein the charge control device further includes a memory in which the assumed potential is stored in advance.   The battery pack according to claim 11, wherein the charging control device performs constant current rapid charging of the battery until the battery voltage reaches the charging completion voltage.   The battery pack according to claim 17, wherein the charge control device performs a constant voltage rapid charge on the battery after the battery voltage reaches the charge completion voltage.   The battery pack according to claim 11, wherein the charge control device is a linear charge control device.   The battery pack according to claim 11, wherein the charge control device is a switching-type charge control device. The battery charge control method executed by a charge control device that supplies power supplied from an input power source to a battery as charging power and charges the battery until the battery voltage reaches a charge completion voltage,
Detecting a potential difference between the positive electrode and the reference electrode as a positive electrode voltage by a positive voltage monitor connected to a positive electrode and a reference electrode of the battery;
Detecting a potential difference between the negative electrode and the reference electrode as a negative electrode voltage by a negative voltage monitor connected to the negative electrode of the battery and the reference electrode;
Based on the positive side voltage detected by the positive side voltage monitor and the negative side voltage detected by the negative side voltage monitor by the charge control unit, the potential of one or both of the positive side and the negative side is assumed. Determining whether or not the potential is lower than the potential, and automatically adjusting the value of the charging completion voltage when detecting that the potential of one or both of the positive electrode and the negative electrode is lower than the assumed potential; and The charge control method characterized by having. When the charge control unit detects that the potential of one or both of the positive electrode and the negative electrode is lower than the assumed potential, the charge control unit automatically sets the value of the charge completion voltage by an amount corresponding to the potential difference from the assumed potential. The charge control method according to claim 21, wherein the charge control method is pulled down.

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