JP2014158395A - Charging device and charging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly charge a battery while effectively suppressing overcharge.SOLUTION: A charging device includes a voltage sensor 16 which, during charging of a lead battery 1, detects its terminal voltage, and a charge control part 14 which stops charging on the basis of a detection voltage VB obtained by this voltage sensor 16. The charge control part 14 stops charging at a time point of satisfying one of a condition that the detection voltage VB is continuously within a predetermined determination range (±0.1 V) and a condition that the detection voltage VB passes a determined determination time from a time point of exceeding the predetermined determination voltage.

Description

  The present invention relates to a charging device and a charging method for a battery (secondary battery) mounted on a vehicle or the like.

  2. Description of the Related Art Conventionally, as a charging device for a vehicle equipped with a rechargeable battery (secondary battery) such as an electric vehicle, a device that charges the battery by supplying a constant current to the battery is known. According to such constant current charging of the battery, the terminal voltage of the battery increases as the charging progresses, and finally the change is eliminated and becomes a substantially constant value. Therefore, many charging devices are configured to detect a point in time when the change in the terminal voltage has converged within a certain range, and to stop the current supply to the battery based on this detection. Note that, as an example of this type of charging device, Patent Document 1 discloses that a battery voltage is detected by detecting the small voltage fluctuation based on the discovery that the terminal voltage fluctuates little by little when the battery is fully charged. A device that stops the supply of current to is also disclosed.

JP-A-9-322423

  However, characteristics such as the amount of power that can be charged into the battery and the charging efficiency vary depending on the usage environment (temperature, etc.) of the battery and the deterioration state (occurrence state of sulfation, etc.). Even when the change does not converge within a certain range, a fully charged state may occur. In addition, it is actually difficult to accurately detect small voltage fluctuations while distinguishing them from noise. Therefore, there is a possibility that long-term overcharge may occur when the battery is in a deteriorated state, and it is desirable to suppress such inconvenience.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of appropriately charging a battery while suppressing overcharge more effectively.

  In order to solve the above-described problems, the present invention provides a charging device for charging a battery with a constant current, a first detection unit for detecting a terminal voltage during charging of the battery, and a first detection unit A charge control unit that stops charging based on detection data, wherein the charge control unit is configured to determine whether the terminal voltage is continuously within a predetermined determination range, or whether the terminal voltage is a predetermined determination. The charging is stopped when one of the second conditions that a predetermined determination time elapses from the time when the voltage is exceeded is satisfied.

  Further, the charging method of the present invention includes a voltage detection step of detecting a terminal voltage of the battery during charging of the battery, and a first condition that the terminal voltage is continuously within a predetermined determination range, or And a charge stopping step of stopping charging when any one of the second conditions that a predetermined determination time elapses from the time when the terminal voltage exceeds the predetermined determination voltage is satisfied.

  According to the charging device and the charging method, in addition to the first condition that the terminal voltage is continuously within the predetermined determination range, the predetermined determination time elapses from the time when the terminal voltage exceeds the predetermined determination voltage. When any of the second conditions is satisfied, charging is stopped as if the battery is fully charged. Therefore, it is possible to charge the battery while more effectively suppressing overcharging as compared with the conventional charging device that stops charging based only on the condition corresponding to the first condition.

  In the above charging apparatus, the second condition includes a plurality of individual conditions in which the determination voltage value is different from each other and the determination time is set shorter as the determination voltage value is higher. It is preferable that a point in time when any one of the individual conditions is satisfied be a point in time when the second condition is satisfied. The charging method further includes a preparatory step for determining the second condition including a plurality of individual conditions in which the determination time is set to be shorter as the determination voltage values are different from each other and the determination voltage value is higher. In the charging stop step, it is preferable that the charging is stopped with a time when any one of the plurality of individual conditions is satisfied as a time when the second condition is satisfied. For example, the second condition preferably includes three or more individual conditions.

  According to these configurations and methods, it is possible to more reliably determine the time when the battery is fully charged by increasing the determination conditions when the battery is fully charged.

  Moreover, in said charging device, the battery used as charge object is specified among the memory | storage part in which several said 2nd conditions each used for charge of the said multiple types of said battery were stored, and the said multiple types of said battery. And a charge control unit, wherein the charge control unit is a type of the battery among the plurality of second conditions stored in the storage unit according to the type of the battery specified by the specification unit. It is preferable to use the second condition that satisfies the above.

  According to this configuration, it is possible to charge a plurality of different types of batteries using a common charging device.

  It is empirically known that the value at which the terminal voltage is stabilized in the fully charged state of the battery depends on the battery temperature or the deterioration state of the battery. Therefore, the charging device includes a second detection unit that detects at least one of a battery temperature or a battery deterioration state, and the charge control unit is configured to satisfy the first condition based on the detection data of the second detection unit. It is preferable to change the determination range.

  According to this configuration, since the reliability of the first condition is improved, the time point when the battery is fully charged can be more accurately specified based on the first condition.

  As described above, according to the battery charging device and the battery charging method of the present invention, it is possible to charge the battery while suppressing overcharge more effectively as compared with the conventional battery charging device and the like.

It is a block diagram which shows the structure of the battery charging device of this invention. It is a flowchart which shows an example of charge control. It is a graph which shows the state of the voltage at the time of charge.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a charging device 10 according to the present invention. The charging device 10 is a stationary or portable charging device that is connected to the lead battery 1 and charges the lead battery 1. In this example, charging of the lead battery 1 will be described, but the charging device 10 can also be applied to charging other batteries such as a lithium ion battery.

  The charging device 10 includes a charger main body 12, a charge control unit 14 that controls the charger main body 12, a voltage sensor 16, a temperature sensor 18, and connection cables 13a and 13b. Moreover, although illustration is abbreviate | omitted, the charging device 10 contains indicators, such as switches, such as a power supply and a charge start switch, and an operation state.

  The charger body 12 rectifies commercial AC power and outputs a DC current. The charger body 12 has a pair of output terminals. The connection cables 13a and 13b are connected to these output terminals. When the lead battery 1 is charged, the ends of the cables 13a and 13b are respectively connected to the terminals 2a and 2b of the lead battery 1 as shown in FIG. Connected. Thereby, the lead battery 1 is charged by the direct current output from the charger main body 12.

  The charging control unit 14 controls the charger main body 12 from the start to the end of charging, and includes various circuits such as a known microcomputer, a memory, and a timer circuit. The charge sensor 14 is electrically connected to the voltage sensor 16 and the temperature sensor 18. The voltage sensor 16 detects the voltage between the terminals of the lead battery 1. On the other hand, the temperature sensor 18 detects the temperature of the lead battery 1 and is fixed to the package side surface of the lead battery 1 at the time of charging.

  That is, the charging control unit 14 performs output control by the charger main body 12 based on detection data detected by the voltage sensor 16 and the temperature sensor 18. Schematically, the charge control unit 14 forces the lead battery 1 to be charged at a constant current when a constant direct current is output from the charger body 12 to the lead battery 1 and a certain condition is satisfied. The charger main body 12 is controlled based on the detection data so that the charging is stopped.

  Next, charging control by the charging control unit 14 will be described. FIG. 2 is a flowchart illustrating an example of charge control by the charge control unit 14.

  This control is started when the charging device 10 is turned on. When this control starts, the charging control unit 14 resets the counter n for counting the number of times of voltage detection and the total time timer TMA for measuring the total charging time, and then determines whether or not the charging start switch is turned on. Judgment is made (steps S1, S3). If it is determined that the charging start switch is turned on (YES in step S3), the charging control unit 14 starts the total time timer TMA to start measuring the total charging time, By controlling, output of direct current to the lead battery 1 is started (steps S5 and S7). That is, charging of the lead battery 1 is started. In this embodiment, the terminal voltage in the fully charged state of the lead battery 1 is 15 V, and the charge control unit 14 controls the charger main body 12 so that, for example, a DC current of 10.4 A is output.

  Next, the charging control unit 14 receives the detection signal (detection voltage VB) from the voltage sensor 16, and the voltage change amount ΔVB (current detection voltage VB (t) −previous detection voltage VB (t−1)). Is calculated, it is determined whether or not the change amount ΔVB is within a predetermined determination range (in this embodiment, within ± 0.1 V) (steps S7 to S13). When it is determined that the change amount ΔVB is within the determination range (YES in step S13), the charge control unit 14 determines whether the counter value is “N” after incrementing the counter n. (Steps S15 and S17). That is, it is determined whether or not the variation ΔVB is within the determination range N times consecutively.

  Here, when it is determined that the counter value is “N” (YES in step S17), the charging control unit 14 determines that the lead battery 1 has reached a fully charged state and outputs a control signal to the charger main body 12. Is output to stop current output (step S39). That is, charging of the lead battery 1 is stopped. In the present embodiment, for example, when N = 3 and the variation ΔVB is within the determination range (within ± 0.1 V) for three consecutive times, the charge control unit 14 indicates that the lead battery 1 is in a fully charged state. Stop charging as if it has reached. On the other hand, if the counter value is not “N”, the process proceeds to the next step S19. If it is determined in step S13 that the change amount ΔVB is not within the determination range (NO in step S13), the charge control unit 14 resets the counter n (step S14). The process proceeds to step S19.

  In step S19, the charging control unit 14 determines whether or not the total time timer TMA has counted a predetermined time T0, that is, whether or not the total charging time has reached the predetermined time T0. This specified time T0 is the maximum time required to charge the lead battery 1 in a new state or a state close thereto to a fully charged state, and is set to, for example, 6 hours in this embodiment.

  If it is determined that the total charging time has reached the specified time T0 (YES in step S19), the charging control unit 14 stops charging the lead battery 1 on the assumption that the lead battery 1 has reached a fully charged state. (Step S39). On the other hand, when it is determined that the total charging time has not reached the specified time T0 (NO in step S19), the charging control unit 14 further uses the first determination voltage V1 in which the detection voltage VB in step S9 is predetermined. It is determined whether or not it has been exceeded (step S21). In the present embodiment, the first determination voltage V1 is, for example, 16V.

  If it is determined that the detection voltage VB does not exceed the first determination voltage V1 (NO in step S21), the process returns to step S7. On the other hand, when it is determined that the detection voltage VB exceeds the first determination voltage V1 (YES in step S21), the charging control unit 14 starts the first determination timer TMB and then sets a predetermined first time. It is determined whether or not one determination time T1 has been measured (steps S23 and S25). In the present embodiment, the first determination time T1 is, for example, 4.2 hours.

  When the first determination time T1 is being measured (YES in step S25), the charge control unit 14 stops charging the lead battery 1 assuming that the lead battery 1 has reached the fully charged state (step S39). ). On the other hand, when the first determination time T1 is not timed (NO in step S25), the charging control unit 14 further determines whether or not the detection voltage VB in step S9 exceeds a predetermined second determination voltage V2. Is determined (step S27). In the present embodiment, the second determination voltage V2 is 17V, for example.

  If the detection voltage VB does not exceed the second determination voltage V2 (NO in step S27), the process returns to step S7. On the other hand, when the detection voltage VB exceeds the second determination voltage V2 (YES in step S27), the charging control unit 14 starts the second determination timer TMC and then sets a predetermined second determination time. It is determined whether or not T2 has been timed (steps S29 and S31). In the present embodiment, the second determination time T2 is, for example, 2.4 hours.

  If the second determination time T2 has been timed (YES in step S31), the charging control unit 14 stops charging the lead battery 1 assuming that the lead battery 1 has reached a fully charged state (step S39). ). On the other hand, when the second determination time T2 is not timed (NO in step S31), the charging control unit 14 further determines whether or not the detected voltage VB in step S9 exceeds a predetermined third determination voltage V3. Is determined (step S33). In the present embodiment, the third determination voltage V3 is 17.5V, for example.

  If the detection voltage VB does not exceed the third determination voltage V3 (NO in step S33), the process returns to step S7. On the other hand, when the detection voltage VB exceeds the third determination voltage V3 (YES in step S33), the charging control unit 14 starts a third determination timer TMD and then sets a predetermined third determination time. It is determined whether or not T3 has been timed (steps S35 and S37). In the present embodiment, the third determination time T3 is, for example, 0.5 hours.

  When the third fixed time T3 is measured (YES in step S37), the charging control unit 14 stops charging the lead battery 1 assuming that the lead battery 1 has reached the fully charged state (step S39). ). On the other hand, when the third determination time T3 is not timed (NO in step S37), the charging control unit 14 returns the process to step S7.

That is, the charging control unit 14
(1) The condition that the detection voltage VB (terminal voltage) is stabilized within a predetermined determination range (within ± 0.1 V) (step S17),
(2) The condition that the total charging time reaches the specified time T0 (6h) (step S19),
(3) A condition that the first determination time T1 (4.2 hours) elapses from the time when the detection voltage VB exceeds the first determination voltage V1 (16V) (step S25),
(4) A condition that the second determination time T2 (2.4 hours) elapses from the time when the detection voltage VB exceeds the second determination voltage V2 (17V) (step S31),
(5) Among the conditions (step S37) that the third determination time T3 (0.5 hours) elapses from the time when the detection voltage VB exceeds the third determination voltage V3 (17.5 V),
When any one of the conditions is satisfied (YES in steps S17, S19, S25, S31, and S37), the charging is stopped. In the present embodiment, the above condition (1) corresponds to the first condition of the present invention. Further, the above conditions (3) to (5) correspond to the individual conditions of the present invention, and therefore the above (3) to (5) as a whole correspond to the second condition of the present invention.

  This charge control is described as follows. That is, the lead battery 1 changes in characteristics such as the amount of power that can be charged and the charging efficiency due to deterioration over time and the use environment (temperature). For example, FIG. 3 shows the relationship between the terminal voltage of the lead battery 1 being charged and time for three lead batteries 1 having different degrees of deterioration. The young ones with circled numbers indicate the state of charge of the new lead battery 1. As shown in the figure, the lead battery 1 tends to have a larger amount of change in terminal voltage (rising voltage) at the initial stage of charge as the deterioration state progresses. Further, depending on the deterioration state of the lead battery 1, the terminal voltage may be in a fully charged state even when the terminal voltage is not sufficiently stable at a constant value. Furthermore, even if the remaining amount is the same, the time required for full charge is also different. These facts indicate that the lead battery 1 is not fully charged by simply detecting when the terminal voltage of the lead battery 1 is stabilized at a constant value or by determining the total charge time and detecting the elapsed time. It means that it cannot be specified correctly. On the other hand, in the charging process of the lead battery 1, the time from when the terminal voltage exceeds a specific voltage value until reaching the fully charged state varies somewhat depending on the deterioration state of the lead battery 1, but is statistically predicted to some extent. Is possible.

  Therefore, in the present embodiment, in the charging process of the lead battery 1, the time from when the terminal voltage (detection voltage VB) of the lead battery 1 exceeds a specific voltage value until actually reaching the fully charged state is statistically obtained. The specific voltage value is determined as the determination voltage, and the time from when the terminal voltage exceeds the determination voltage until the fully charged state is reached is determined as the determination time. From the relationship between the determination voltage and the determination time, the lead battery 1 is fully charged. We decided to identify the point of time when charging was reached. In the present embodiment, in order to increase the reliability in specifying the time point when the lead battery 1 is fully charged, the determination times T1 to T3 are determined for the three determination voltages V1 to V3 as described above. ing. In addition, although each determination time T1-T3 becomes short, so that the value of each determination voltage V1-V3 is high, this is because time until full charge becomes short, so that a terminal voltage is high.

  As described above, the first determination time T1 elapses from the time point (3) when the detection voltage VB exceeds the first determination voltage V1 under the conditions (1) and (2) that have been used conventionally. (4) The second determination time T2 elapses from the time when the detection voltage VB exceeds the second determination voltage V2, and (5) the third determination time T3 (from the time when the detection voltage VB exceeds the third determination voltage V3). The time when any one of the five conditions including the condition that 0.5 hour) has been added is regarded as the time when the lead battery 1 is fully charged. Yes.

  According to such charge control, since charging of the lead battery 1 is stopped when any of the above conditions (1) to (5) is satisfied, the detection voltage VB (terminal) is conventionally used. Overcharge is more effective than a charging device that stops charging with a fully charged state when only the condition that the voltage is stable within the specified range or the condition that the total charging time reaches the specified time is satisfied. In this way, the battery can be charged while being suppressed.

  Specifically, referring to FIG. 3, for example, assuming that a lead battery 1 that has not progressed deterioration (circled numeral 1 in the figure) is fully charged at time t2, the lead battery 1 that has progressed deterioration. (Circled number 3 in the figure) is considered to be in a fully charged state at time t1 earlier than time t2 because the amount of change in the terminal voltage (rising voltage) at the beginning of charging is large. In such a case, in the case of the conventional charging device that specifies the fully charged state only under the conditions corresponding to the above (1) or (2), the lead battery 1 that has not deteriorated is in a fully charged state. As shown in the figure, the terminal voltage of the lead battery 1 that has progressed to a certain degree of accuracy can be identified to a certain degree, but the terminal voltage has not yet stabilized at a constant value, and the total charging time has reached the specified time. Therefore, it is difficult to stop charging by detecting the fully charged state at the time t1. Therefore, for example, long-term overcharge is caused until the total charge time reaches a specified time.

  On the other hand, according to the charging device 10 of the above embodiment, even when the condition (1) or (2) is not satisfied at time t1, for example, the condition (5), that is, the detection voltage VB, is satisfied. When the condition that the third determination time T3 elapses from the time when the voltage exceeds the third determination voltage V3 is satisfied, charging of the lead battery 1 is stopped at the time t1 or very close thereto. . Accordingly, without overcharging, and even when overcharging occurs, the time can be reduced to a short time. Therefore, it is possible to charge the battery more appropriately while effectively suppressing overcharge.

  In the present embodiment, the voltage of the fully charged state of the lead battery 1 is 15V, while the determination voltages V1 to V3 are set to values higher than 15V. This is because the voltage applied to the lead battery 1 exceeds 15V in order to keep the output current from the charger main body 12 at a constant value (10.4 A).

  The charging device 10 of the present invention has been described above. However, the above embodiment is an example of a preferred embodiment of the battery charging device and the battery charging method according to the present invention. The appropriate charging method can be appropriately changed without departing from the gist of the present invention. For example, the following configuration or method may be applied.

  For example, although the said embodiment makes object the specific lead battery 1, the structure which makes object the some kind of lead battery 1 may be sufficient. In this case, the following configuration can be applied. That is, since the specific numerical value of each condition of said (1)-(5) changes with types (type distinguished by a capacity | capacitance, a charging current value, etc.) of the lead battery 1, for example, said (1)-( 5) As each condition, a storage unit that stores conditions corresponding to each type of the lead battery 1, a switch or the like (corresponding to the specifying unit of the present invention) for specifying the type of the lead battery 1 to be charged 2 is provided in the charging device 10, and the charging control unit 14 reads out the conditions corresponding to the type of the lead battery 1 specified by the switch or the like from the storage unit, and then executes the charging control according to the flowchart of FIG. Configure as follows. According to such a configuration, it is possible to charge a plurality of types of lead batteries 1 with the common charging device 10, and it is possible to receive the same operational effects as in the above embodiment for any type. .

  In addition, in the above condition (1), the range (determination range) in which the detection voltage VB (terminal voltage) is stable when fully charged varies depending on the temperature and the degree of deterioration of the lead battery 1. Therefore, the charging control unit 14 may be configured to change the determination range of the condition (1) based on the temperature and the degree of deterioration of the lead battery 1. Specifically, the charging device 10 is provided with a storage unit that stores table data or the like that defines the relationship between the temperature of the lead battery 1 and the determination range, and the charging control unit 14 detects the temperature sensor 18. The determination range may be changed based on the temperature and the table data. On the other hand, for the configuration in which the determination range is changed based on the degree of deterioration, it is possible to use the characteristic that the amount of change in the terminal voltage (rising voltage) at the initial stage of charging changes depending on the deterioration state of the lead battery 1. That is, the charging device 10 is provided with a storage unit that stores table data or the like that defines the relationship between the amount of change in the detected voltage VB (terminal voltage) per unit time and the determination range, and the charging control unit 14 The determination range is changed based on the detection voltage VB and the table data. In this case, as another parameter indicating the deterioration state, for example, a use period of the lead battery 1 may be applied, and table data or the like defining a relationship between the use period and the determination range may be stored. According to these configurations, since the reliability of the condition (1) is improved, the time point when the lead battery 1 is fully charged can be more accurately specified based on the condition (1). It becomes. In these configurations, in the configuration in which the determination range is changed based on the detection of the battery temperature, the temperature sensor 18 corresponds to the second detection unit of the present invention, and based on the detection of the change amount of the detection voltage VB. In the configuration for changing the determination range, the voltage sensor 16 and the charge control unit 14 correspond to a second detection unit of the present invention.

  In the above embodiment, three individual conditions (conditions (3) to (5) above) are included as the second condition of the present invention, but the individual conditions are two or less, or four or more. The specific number and numerical value of the individual conditions may be determined so that the full charge state can be specified more accurately.

DESCRIPTION OF SYMBOLS 1 Lead battery 10 Battery charger 12 Charger main body 14 Charge control part 16 Voltage sensor 18 Temperature sensor

Claims (7)

A charging device for charging a battery with a constant current,
A first detector for detecting a terminal voltage of the battery during charging;
A charge control unit that stops charging based on the detection data of the first detection unit,
The charging control unit is configured such that a first condition that the terminal voltage is continuously within a predetermined determination range, or a second condition that a predetermined determination time elapses from the time when the terminal voltage exceeds a predetermined determination voltage. A charging device, wherein charging is stopped when any of the above is satisfied. The charging device according to claim 1,
The second condition includes a plurality of individual conditions in which the determination voltage is different from each other and the determination time is set shorter as the determination voltage is higher.
The charging control unit is characterized in that a time point when any one of the individual conditions is satisfied is set as a time point when the second condition is satisfied. The charging device according to claim 2,
A storage unit storing a plurality of second conditions respectively used for charging a plurality of types of batteries; and a specifying unit for specifying a battery to be charged among the plurality of types of batteries. ,
The charging control unit uses the second condition that matches the type of the battery among the plurality of second conditions stored in the storage unit according to the type of the battery specified by the specifying unit. A charging device. The charging device according to claim 2 or 3,
The charging device according to claim 2, wherein the second condition includes three or more individual conditions. The charging device according to any one of claims 1 to 4,
Including a second detection unit for detecting at least one of the battery temperature or the battery deterioration state;
The charging device, wherein the charging control unit changes the determination range of the first condition based on detection data of the second detection unit. A charging method for charging a battery at a constant current,
A voltage detecting step of detecting a terminal voltage of the battery during charging of the battery;
Either the first condition that the terminal voltage is continuously within a predetermined determination range or the second condition that a predetermined determination time elapses from the time when the terminal voltage exceeds the predetermined determination voltage is satisfied. And a charge stopping step of stopping the charging at a point in time. The charging method according to claim 6, wherein
The method further includes a preparatory step for determining the second condition including a plurality of individual conditions in which the determination voltage values are different from each other and the determination voltage value is higher as the determination voltage value is higher. The charging method is characterized in that the charging is stopped with a time point when any one of the individual conditions is satisfied as a time point when the second condition is satisfied.

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