JP5064244B2 - Fast charging method and charger used therefor - Google Patents

Description

  The present invention relates to a rapid charging method for shortening the charging time of a battery.

  8A and 8B are graphs showing the relationship between the temperature and time of the charger main body and the charging current value and time in the conventional battery charging method. In the graph, the process using the preliminary current is omitted.

  In the conventional charging method, a reserve current is supplied to detect the voltage of the battery, and the constant current charging mode (time a to b) is entered. The battery is charged through the steps of the constant current mode and the constant voltage mode (time b to d) just before the end of charging. In the constant current mode, charging is performed with a constant current, and immediately after the start, the temperature of the charger body increases with energization. When the charger body temperature rises to a certain extent, it becomes constant there and is charged as it is with a constant current. This charging current value does not reach a temperature (allowable maximum temperature T4) at which the charger main body is damaged and cannot be used due to a temperature rise during charging by the time (time b) for shifting to the constant voltage mode. It is determined so as to have a current value.

  In the constant voltage mode, when the voltage reaches near the charge end voltage, the voltage is fixed at the upper limit, and charging is performed at a constant voltage. As time elapses in the constant voltage charging state, the battery is charged, and the charging current naturally decreases (time b to c). Along with this, the charger body temperature decreases. Thereafter, the charging current is set to a constant current value 5 at a certain time (time c). Charging is performed at a slight charging current value 5 at this time, and the charging is terminated when the battery is fully charged (time d). Also during this time, the charger body temperature gradually decreases. By performing this constant voltage mode, the battery life can be extended.

  However, immediately after the start of the constant current charging mode, the temperature of the charger main body is cold, and there is a margin in the temperature increase range up to the allowable maximum temperature. Nevertheless, the charging current value is charging at a constant current with a current value such that the charger body does not reach the maximum allowable temperature. For this reason, the charging current value is lower than the margin of the temperature rise of the charger main body in the initial constant current charging mode. Therefore, as a result, charging takes time.

  A charging voltage switching setting method is disclosed in Patent Document 1. However, paragraph 0020 and FIG. 4 of Patent Document 1 describe a charging sequence in which constant voltage charging is performed after constant current charging, similar to the above-described charging method, and is also a charging method that takes time to charge.

JP 2007-60772 A

  The present invention has been made in consideration of the above-described prior art, and an object thereof is to provide a quick charging method capable of performing charging at a current value as high as possible and shortening a charging time, and a charger used therefor. .

In order to achieve the above object, according to the first aspect of the present invention, a battery to be charged is connected to the charger body, a low-current preliminary current is passed, and then the battery voltage is detected, and the charging mode is entered. The battery is charged and applied to a charging method that shifts to a constant voltage charging mode in which charging is performed at a constant voltage when the battery reaches near full charge during the charging mode. The temperature at which the charger main body is damaged due to temperature rise and cannot be used is stored in advance as an allowable maximum temperature, and the initial charging current value that flows immediately after the start of the charging mode is the maximum allowed on the circuit of the charger main body. The current value is set to a current value, and the current value is gradually lowered so that the temperature of the charger body does not reach the allowable maximum temperature by the constant voltage charging mode, and the current before the transition to the constant voltage mode is reached. A lowest after starting charging, and provides a fast charging method, characterized in that the temperature of the charger body and the current value so as to maintain the temperature close to the allowable maximum temperature.

  The invention of claim 2 is characterized in that the current value lowering step is performed while taking into account that the temperature of the charger main body continues to rise for a predetermined time even immediately after the current value is lowered.

  The invention of claim 3 is characterized in that charging is stopped when the temperature of the charger main body reaches the allowable maximum temperature during the charging mode.

  The invention of claim 4 is characterized in that charging is stopped when the charger main body temperature does not reach a predetermined temperature during charging at the initial charging current value.

  Further, the invention of claim 5 is a charger used in the rapid charging method according to any one of claims 1 to 4, wherein a temperature detection device is provided on a surface of the charger main body or a heat generating component constituting the charger main body. A charger is provided in which is attached.

  According to the first aspect of the present invention, in the charging method having the charging mode and the constant voltage charging mode, a temperature at which the charger main body is damaged and cannot be used due to a temperature rise during charging is stored in advance as an allowable maximum temperature. Thus, charge control based on this allowable maximum temperature becomes possible. In addition, the initial charging current value that flows immediately after the start of the charging mode is set to the maximum current value allowed on the circuit of the charger body (current value that reaches the maximum allowable temperature), and the temperature of the charger body is allowed before the constant voltage charging mode. The current value is controlled by gradually decreasing the current value so as not to reach the maximum temperature. For this reason, it is possible to perform charging by flowing a high current value from the start of the charging mode, then gradually decreasing the current value, and flowing a high current that does not reach the allowable maximum temperature. Therefore, the charging time can be greatly shortened.

  According to the second aspect of the present invention, the current value lowering step is performed while considering that the temperature of the charger body continues to rise for a predetermined time even immediately after the current value is lowered. Nevertheless, the charger main body temperature can be prevented from reaching the allowable maximum temperature.

  According to the invention of claim 3, when the temperature of the charger main body reaches the allowable maximum temperature during the charging mode, the charging is stopped. For this reason, damage to the charger main body can be reliably prevented and the charging time can be shortened.

  According to the fourth aspect of the present invention, charging is stopped when the charger main body temperature does not reach the predetermined temperature during charging at the initial charging current value at the start of the charging mode. If the charger main body temperature does not reach the predetermined temperature even though the charging current having a high current value is flowing, it is considered that some failure has occurred in the charger main body. For this reason, it is possible to prevent useless charging by detecting a failure of the charger body.

  According to the invention of claim 5, since the temperature detection device is attached to the charger main body surface or the heat generating component constituting the charger main body, the current value is controlled based on the detected temperature, and the charging time is shortened. Can be achieved. In particular, if a temperature detection device is attached to a place where heat is most likely to be generated, damage to the charger body due to temperature rise can be prevented more reliably.

  The present invention connects a battery to be charged to the charger body, passes a low-current standby current, detects the voltage of the battery after that, shifts to a charging mode and charges the battery, It is applied to a charging method that shifts to a constant voltage charging mode in which charging is performed at a constant voltage when the battery reaches almost full charge during the charging mode, and the charger main body is damaged due to a temperature rise during charging. In such a case, the initial charging current value that flows immediately after the start of the charging mode is set as the maximum current value allowed in the circuit of the charger body, and the constant voltage charging mode is reached. The current value is gradually lowered so that the temperature of the charger body does not reach the allowable maximum temperature, and the current value before the transition to the constant voltage mode is set to the temperature of the charger body. It is rapid charging method and charger used in this and the current value so as to maintain the temperature close to the volume maximum temperature.

  FIG. 1 shows an example of charging a battery using the rapid charging method according to the present invention, where (A) shows the temperature and time of the charger body, and (B) shows the relationship between the charging current value and time. FIG. In the graph, the process using the preliminary current is omitted. Further, the values of T1 to T4 and 1 to 5 may be different for each embodiment.

  The rapid charging method according to the present invention includes a charging mode (time a to e) and a constant voltage charging mode (time e to g). As shown in the graph, when charging of the battery is started (time a), that is, immediately after the start of the charging mode, charging is performed with a current having an initial charging current value of 1. The current value 1 is a maximum current value that the charger body allows in a circuit (such as a thyristor) (a very high current value such that the charger body reaches the allowable maximum temperature T4 in a short time). This allowable maximum temperature can be obtained by empirical rules or simulation. Accordingly, when charging is performed at the initial charging current value 1, the temperature of the charger body rapidly increases.

  When the temperature of the charger body reaches T1 (time b), the charging current is changed to 2 lower than 1. Since this current value 2 is also a high current value, the temperature of the charger body continues to rise. Subsequently, when the temperature of the charger main body reaches T2 (time c), the charging current is changed to 3 lower than 2. Thereby, after changing to 3, the gradient of the temperature rise of the charger body becomes gentle after a while. In this way, immediately after switching from a high current to a low current, the temperature of the charger body does not suddenly decrease, and considering that the temperature continues to rise for a predetermined time, the current value is changed from a very high current value 1 to a current value 3. 1), once the current value 2 between 1 and 3 is passed, the temperature rise of the charger body after changing to 3 can be moderated as shown in (A). The maximum temperature T4 will not be reached.

  Further, when the charger body temperature reaches T3 (time d), the charging current is changed to 4 lower than 3. This 4 is a current value that can maintain a state in which the temperature of the charger body is close to the allowable maximum temperature T4. Thereby, about time de, the maximum electric current in the range in which the temperature of a charger main body does not reach permissible maximum temperature can be sent, and rapid charge is attained.

  By performing such a charging method, the charging time can be shortened. In particular, the effect is obtained by making the initial charging current value a large current and gradually lowering the current value thereafter, instead of the constant current charging as in the prior art. If a current of 4 in the figure is passed, the charger main body can be charged while maintaining a temperature close to the allowable maximum temperature T4 (search rate) after a predetermined time has elapsed. In the present invention, 4 is used as a current value before shifting to a constant voltage mode, which will be described later, and the time until 4 is supplied (until the charger body temperature approaches the allowable maximum temperature T4) is shortened. Therefore, a current (1) higher than 4 is supplied to make the gradient of the temperature rise at the beginning of charging steep. In addition, immediately after switching from a high current to a low current, the temperature of the charger body is not decreased suddenly, and the current value is gradually decreased in consideration of the fact that it continues to rise for a predetermined time. Can be charged in such a manner that the temperature does not reach T4, but the temperature close to T4 is maintained.

  Charging is continued at the charging current 4, and when the battery reaches nearly full charge (time e), the mode shifts to the constant voltage charging mode. In this constant voltage charging mode, the battery voltage at full charge is fixed at the upper limit, and charging is performed at a constant voltage. The battery is charged in the constant voltage charging state, and the charging current naturally decreases during that time (time ef). Along with this, the charger body temperature decreases. Thereafter, the charging current is set to a constant low current value 5 at a certain time (time f). The battery is charged with this slight charging current value 5 and is fully charged when time is full (time g). During this period (time f to g), the charger body temperature gradually decreases. By performing this constant voltage mode, the battery life can be extended.

  FIG. 2 shows another example when the battery is charged using the rapid charging method according to the present invention, (A) shows the temperature and time of the charger body, and (B) shows the charging current value and time. It is a graph which shows the relationship. In the graph, the process using the preliminary current is omitted.

  The rapid charging method according to the present invention includes a charging mode (time a to e) and a constant voltage charging mode (time e to g). As shown in the graph, when charging of the battery is started (time a), that is, immediately after the start of the charging mode, charging is performed with a current having an initial charging current value of 1. This current value 1 is a very high current value such that the charger main body reaches the allowable maximum temperature in a short time. This allowable maximum temperature can be obtained by empirical rules or simulation. Accordingly, when charging is performed at the initial charging current value 1, the temperature of the charger body rapidly increases.

  When the temperature of the charger body reaches T1 (time b), the charging current is changed to 2 lower than 1. Thereby, after changing to 2, the gradient of the temperature rise of the charger body becomes gentle after a while. When the charging is continued and the temperature of the charger body reaches T2 (time c), the charging current is changed to 3 lower than 2. As a result of this change, the gradient of the temperature rise of the charger body becomes even gentler. When the charging is continued and the temperature of the charger body reaches T3 (time d), the charging current is changed to 4 lower than 3. As a result of this change, the gradient of the temperature rise of the charger body becomes even gentler.

  Charging is continued at the charging current 4, and when the battery reaches nearly full charge (time e), the mode shifts to the constant voltage charging mode. In this constant voltage charging mode, the battery voltage at full charge is fixed at the upper limit, and charging is performed at a constant voltage. The battery is charged in the constant voltage charging state, and the charging current naturally decreases during that time (time ef). Along with this, the charger body temperature decreases. Thereafter, the charging current is set to a constant low current value 5 at a certain time (time f). The battery is charged with this slight charging current value 5 and is fully charged when time is full (time g). During this period (time f to g), the charger body temperature gradually decreases. By performing this constant voltage mode, the battery life can be extended.

  By performing such a charging method, the charging time can be shortened. In particular, the effect is obtained by making the initial charging current value a large current and gradually lowering the current value thereafter, instead of the constant current charging as in the prior art. The fact that the charger main body reaches the allowable maximum temperature T4 during the charging time by flowing a large current means that the temperature of the charger main body is detected step by step (T1 to T3) and gradually matches the temperature. This is prevented by lowering the current value (1 to 4). The reason for gradually decreasing the current value by detecting the temperature of the charger body step by step is to charge with a large current such as 1, and even if the current value is suddenly lowered, the temperature rise of the charger body suddenly This is to prevent the charger main body from reaching the allowable maximum temperature T4 in consideration of the rising gradient. By performing such current value control, the temperature of the charger main body tends to approach the maximum allowable temperature T4 as much as possible. Therefore, it is possible to control the flow of a large current to the limit without reaching the allowable maximum temperature T4, and the charging time can be greatly shortened. In Example 2, the temperature of the charger main body was not lowered before the transition to the constant voltage charging mode, and the charge current value could be increased to the limit so that the temperature of the charger main body would approach the allowable maximum temperature as much as possible. An example is shown.

  FIG. 3 shows still another example when the battery is charged using the rapid charging method according to the present invention, where (A) shows the temperature and time of the charger body, and (B) shows the charging current value and time. It is a graph which shows the relationship. In the graph, the process using the preliminary current is omitted.

  As shown in the graph, it is the same as in the second embodiment until the temperature of the charger main body reaches T3 at time d and the charging current is changed from 3 to 4. Thereafter, the case where the temperature of the charger main body decreases from time d to e is shown (actually, the temperature of the charger main body continues to increase for a predetermined time from time d). Even in this case, the current value is charged as it is, and the constant voltage charging mode is entered at time e. In Example 3, since the charger main body temperature decreased over time d to e (because the temperature of the charger main body did not rise as close as possible to the maximum allowable temperature), charging can be performed by energizing a large current to the limit. Not a thing. However, the contribution to the shortening of the charging time is larger when the charging can be performed with the large currents 1 and 2 over the charging times a to c at the initial stage of charging than in this time zone. For this reason, the overall charging time is not so different from that of the second embodiment.

  FIG. 4 shows still another example when the battery is charged using the rapid charging method according to the present invention, (A) shows the temperature and time of the charger body, and (B) shows the charging current value and time. It is a graph which shows the relationship. In the graph, the process using the preliminary current is omitted.

  As shown in the graph, it is the same as in the second embodiment until the temperature of the charger main body reaches T3 at time d and the charging current is changed from 3 to 4. However, since the temperature of the charger main body has reached the allowable maximum temperature T4 at time e, charging is stopped. That is, the charging current is set to zero when T4 is reached (time e). Thereby, the temperature of the charger body gradually decreases thereafter. The battery charging method according to the present invention is intended to reduce the charging time by flowing a large current so that the temperature of the charger body is as close as possible to the maximum allowable temperature. In this way, charging is immediately stopped in this way, and the charger main body is reliably prevented from being damaged.

  FIG. 5 shows still another example when the battery is charged using the rapid charging method according to the present invention. (A) shows the temperature and time of the charger body, and (B) shows the charging current value and time. It is a graph which shows the relationship. In the graph, the process using the preliminary current is omitted.

  As shown in the graph, when the charger main body temperature does not reach the predetermined temperature (T0) even though the charging is started by supplying a large current 1 at the start of charging (time a), It is considered that a failure has occurred. For this reason, charging is stopped. In the figure, an example in which charging is stopped at time c is shown. The timing for stopping the charging can be appropriately changed by individually determining the time when the temperature does not reach the predetermined temperature (T0). Thereby, a failure of the charger body can be detected in advance, and useless charging can be prevented.

  FIG. 6 is a flowchart of the rapid charging method according to the present invention.

Step S1:
After connecting the battery to the charger body, a small amount of current (preliminary current) is passed in order to obtain information such as whether this connection has been made reliably. This step is the same as that used in a general charging method.

Step S2:
Detect battery voltage. This detection is performed by, for example, a voltage sensor provided in the charger main body.

Step S3:
It is determined whether or not the battery voltage detected in step S2 is greater than or equal to a predetermined value.

Step S4:
If the battery voltage is equal to or lower than the predetermined value in step S3, the temperature of the charger body is detected. This detection is performed using a temperature sensor (temperature detection device) provided in the charger body.

Step S5:
It is determined whether or not the charger main body temperature has reached T4, that is, a temperature at which the charger main body is damaged and cannot be used.

Step S6:
If the charger main body has reached the allowable maximum temperature (T4) in step S5, the charging is stopped (stopped).

Step S7:
If the charger main body does not reach the allowable maximum temperature (T4) in step S5, it is determined whether or not the temperature is equal to or higher than the temperature T3 that is lower than T4.

Step S8:
When the charger main body has reached the temperature T3 in step S7, the charging current value is set to 4, and the battery is charged. Then, it returns to step S2.

Step S9:
If the charger main body has not reached the temperature T3 in step S7, it is determined whether or not the temperature is equal to or higher than the temperature T2 that is lower than T3.

Step S10:
If the charger main body has reached the temperature T2 in step S9, the charging current value is set to 3 higher than 4 to charge the battery. Then, it returns to step S2.

Step S11:
If the charger main body has not reached the temperature T2 in step S9, it is determined whether or not the temperature is equal to or higher than the temperature T1, which is a temperature lower than T2.

Step S12:
If the charger main body has reached the temperature T1 in step S11, the charging current value is set to 2 higher than 3 to charge the battery. Then, it returns to step S2.

Step S13:
If the charger main body has not reached the temperature T1 in step S11, the charging current value is set to 1 higher than 2 to charge the battery. Then, it returns to step S2.

Step S14:
If the battery voltage is greater than or equal to a predetermined value in step S3, that is, if the battery voltage has reached a voltage value near the full charge of the battery, the mode shifts to the constant voltage charging mode and charging is performed at the voltage value.

Step S15:
It is determined whether the charging current is equal to or less than a predetermined current value. In constant voltage charging, since the charging current naturally decreases, it is determined whether or not this is equal to or less than a predetermined low current value. If it is equal to or greater than the predetermined low current value, the process returns to step S2.

Step S16:
When the charging current value is equal to or lower than the predetermined low current value in step S15 (actually when the charging current value has decreased to the predetermined low current value), charging is performed at the low current value. Thereafter, when the battery is fully charged, the charging is terminated. Thus, the lifetime of a battery can be extended by performing the charging current near full charge with a low current.

  In Steps S4 to S12, four temperatures T1 to T4 are provided as threshold values for the charger body temperature including the allowable maximum temperature T4. However, the number of threshold values can be changed as appropriate.

  FIG. 7 is a schematic configuration diagram of a charger used in the rapid charging method according to the present invention.

  The charger used in the rapid charging method according to the present invention includes a charger body 1 having an input terminal 2 and an output terminal 3. The input terminal 2 and the output terminal 3 are connected via a transformer 4. On the primary side of the transformer 4, a filter circuit 5, an AC / DC conversion circuit 6, capacitors 7a and 7b, resistance members 8a and 8b, and a switching circuit 9 are provided. On the secondary side of the transformer 4, a rectifier circuit 10, a smoothing circuit 11, and an output circuit 12 are provided. On the other hand, the charger main body 1 includes an internal power supply circuit 13, a current / voltage control circuit 14, and a CPU 15. A battery (not shown) to be charged is connected to the output terminal 3.

  When charging the battery, the power supplied from the input terminal 2 is filtered through the filter circuit 5, and the current is alternately stored in the two capacitors 7a and 7b. At this time, since the ground side passes through the AC / DC conversion circuit 6, the current stored in the capacitors 7a and 7b is a direct current. The current stored in the capacitors 7 a and 7 b flows to the midpoint of the primary winding of the transformer 4.

  On the other hand, the supply power from the input terminal 2 is also supplied to the internal power supply circuit 13. The internal power supply circuit 13 is for securing a power supply in the charger body 1 and is connected to the switching circuit 13, the current / voltage control circuit 14, and the CPU 15.

  The switching circuit 9 causes a current to flow alternately from the middle point of the transformer 4 for a predetermined time (in the directions of arrows A and B). The switching circuit 9 is a gate drive circuit such as an FET, and switches the direction in which a current flows from the middle point of the transformer 4 every predetermined time when a voltage is applied to the gate.

  With the above action, the power supply voltage is converted into an output voltage for charging by the transformer 4 and rectified by the rectifier circuit 10. The voltage rectified in this way is smoothed by the smoothing circuit 11 and charged from the output circuit 12 to the battery via the output terminal 3. At this time, the amount of charge is determined while viewing the voltage of the battery connected to the output terminal 3 by the CPU 15 via the current-voltage control circuit 14. The current / voltage control circuit 14 is a control circuit for controlling the voltage and current to the output terminal 3, and the current / voltage control circuit 14 is controlled by the CPU 15.

  A temperature detector 16 is attached to the switching circuit 9. The temperature detection device 16 detects the temperature of the charger body 1 and uses the detection result for the above-described rapid charging method. The temperature detection device 16 is, for example, on each element constituting the switching circuit 9, the surface of a heat generating component such as a rectifier diode, a bridge diode, a transformer, a choke coil, or a line filter, the periphery thereof, or the surface of a case covering them. It may be attached. Regardless of the temperature measured at any location, the current value is controlled based on the detected temperature, and the charging time can be shortened by the rapid charging method. In particular, if a temperature detection device is attached to a place where heat is most likely to be generated, damage to the charger body due to temperature rise can be prevented more reliably.

The example at the time of charging using the battery charging method which concerns on this invention is shown, (A) is the temperature and time of a charger main body, (B) is a graph which shows the relationship between charging current value and time. . The graph which shows another example when it charges using the battery charging method which concerns on this invention, (A) is the temperature and time of a charger main body, (B) is the graph which shows the relationship between charging current value and time It is. The another example when it charges using the battery charging method which concerns on this invention is shown, (A) is the temperature and time of a charger main body, (B) is a graph which shows the relationship between a charging current value and time. FIG. The another example when it charges using the battery charging method which concerns on this invention is shown, (A) is the temperature and time of a charger main body, (B) is a graph which shows the relationship between a charging current value and time. FIG. The another example when it charges using the battery charging method which concerns on this invention is shown, (A) is the temperature and time of a charger main body, (B) is a graph which shows the relationship between a charging current value and time. FIG. It is a flowchart of the quick charge method which concerns on this invention. It is a schematic block diagram of the charger used for the quick charge method which concerns on this invention. (A) in the conventional battery charging method is a graph which shows the temperature and time of a charger main body, and (B) is a graph which shows the relationship between a charging current value and time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Charger main body, 2: Input terminal, 3: Output terminal, 4: Transformer, 5: Filter circuit, 6: AC / DC conversion circuit, 7a, 7b: Capacitor, 8a, 8b: Resistance member, 9: Switching circuit DESCRIPTION OF SYMBOLS 10: Rectifier circuit, 11: Smoothing circuit, 12: Output circuit, 13: Internal power supply circuit, 14: Current voltage control circuit, 15: CPU, 16: Temperature detection apparatus

Claims (5)

A battery to be charged is connected to the charger body, a preliminary current having a low current value is supplied, and then the voltage of the battery is detected, the charging mode is entered and the battery is charged,
When the battery reaches near full charge during the charging mode, it is applied to a charging method that shifts to a constant voltage charging mode in which charging is performed at a constant voltage,
Preliminarily store the temperature to the extent that the charger main body is damaged due to temperature rise during charging and can no longer be used as the allowable maximum temperature,
The initial charging current value that flows immediately after the start of the charging mode is the maximum current value allowed on the circuit of the charger body,
Gradually lower the current value so that the temperature of the charger body does not reach the allowable maximum temperature by the constant voltage charging mode,
The current value before the transition to the constant voltage mode is set to a current value that is the lowest after the start of charging and that maintains the temperature of the charger body close to the allowable maximum temperature. Fast charging method.   2. The rapid charging according to claim 1, wherein the step of reducing the current value is performed while considering that the temperature of the charger body continues to rise for a predetermined time even immediately after the current value is lowered. Method.   3. The rapid charging method according to claim 1, wherein charging is stopped when the temperature of the charger main body reaches the allowable maximum temperature during the charging mode.   4. The rapid charging method according to claim 1, wherein charging is stopped when the charger main body temperature does not reach a predetermined temperature during charging at the initial charging current value. 5.   The charger used for the rapid charging method according to any one of claims 1 to 4, wherein a temperature detection device is attached to the surface of the charger main body or a heat generating component constituting the charger main body. vessel.

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