JP2013192323A - Charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger for charging a plurality of lithium ion battery packs of different battery cell sizes, capable of setting appropriate charging currents corresponding to kinds of battery cell sizes.SOLUTION: A controller of a charger starts to charge a battery pack with a charging current Ithat matches a battery cell for 18650 of large battery capacity, and by detecting battery voltage within a predetermined time after the charging start and/or cell temperature inclination, continues the charging by switching to a charging current Ithat matches a battery cell for 14500 of small battery capacity when the inclination is equal to or larger than a specified value.

Description

  The present invention relates to a charging device for charging a battery pack including one or a plurality of secondary battery cells and having different battery cell shapes and connection forms, and particularly corresponds to a battery type depending on the battery cell shape of the battery pack. The present invention relates to a charging device that can set an appropriate charging current or charging voltage.

  In a cordless type power tool, a battery pack composed of a lithium ion secondary battery (hereinafter simply referred to as “lithium ion battery”) as a power source has been widely used. Lithium ion battery packs are characterized by a small and light weight because the cell nominal voltage is higher and the output density is higher than that of nickel cadmium batteries and nickel metal hydride batteries. Furthermore, the discharge efficiency is good, discharge is possible even in a relatively low temperature environment, and a stable voltage can be obtained in a wide temperature range. For this reason, the lithium ion battery pack is expected as a power source for reducing the weight, size and working efficiency of the electric tool.

  Generally, a charging device of a lithium ion battery pack controls charging by a constant current / constant voltage control method. In particular, charging of a lithium ion battery pack may damage secondary battery cells if overcharged. Therefore, the control device of the charging device first charges with a constant charging current, When the voltage per cell reaches a predetermined charging voltage (for example, about 4.20 V / cell), charging is performed by switching to a constant charging voltage. After that, when the charging current gradually decreases and becomes equal to or less than the end current value, control is performed so as to detect the full charge and stop the charging. For this reason, the charging device has a control circuit for controlling the charging current or the charging voltage.

  A battery pack composed of battery cells (unit cells) such as lithium ion secondary batteries is generally composed of an assembled battery in which a plurality of battery cells are connected in parallel or in series. For example, a battery pack of 18650 size including a battery pack in which four battery cells of a lithium ion secondary battery having a nominal voltage of 3.6 V / cell are connected in series has a rating of an output voltage of 14.4V. In addition, the current capacity of a battery pack (assembled battery) is changed by connecting battery cells of a lithium ion secondary battery in parallel. As described above, since the appropriate charge current and charge voltage of the battery pack vary depending on the number of battery cells accommodated and the connection form, for example, Patent Document 1 discloses an appropriate charge current or charge corresponding to the type of lithium ion battery pack. The voltage can be set.

JP 2009-106117 A

  FIG. 9 is a view showing dimensions of a lithium ion battery used for an electric tool, and (1) is a size that has been often used conventionally. This lithium ion battery has a cylindrical shape with a diameter of 18 mm and a height of 65 mm, and this is called 18650 size. The first two digits “18” of the number indicate the diameter, and the last three digits “650” indicate the length (displayed in units of 0.1 mm). In the conventional battery pack, different types of battery packs are configured depending on the number of connected 18650 size lithium ion batteries and the connection form. Therefore, in the technique of Patent Document 1, the lithium ion battery cell 2a is included in the battery pack. The charging device sets the charging current and the charging voltage of the lithium ion battery pack 2 in response to a control signal generated from the determination resistor 7 of the battery pack 2. Configured to do.

  However, in recent years, lithium ion batteries have been reduced in size and capacity, and not only 18650 size battery cells but also so-called 14500 size lithium ion batteries are being studied for practical use in the field of electric power tools. FIG. 9 (2) shows a 14500-size lithium ion battery, which is cylindrical and has a diameter of 14 mm and a height of 50 mm. This size is almost the same as what is called “AA size”, “R6 size”, or “AA size” of a dry cell (primary battery).

  A battery pack of 14500 size including a battery pack in which four battery cells of 14500 size lithium ion secondary battery are connected in series with each other has a rating of an output voltage of 14.4 V. Therefore, a battery of 18650 size lithium ion secondary battery The rated voltage is the same as that of an assembled battery in which four cells are connected in series. Care must be taken when charging battery packs having the same voltage but different types of battery cells. For example, an existing charging device that can charge a battery pack having 18650-size battery cells has an inadequate charge current for a 14500-size battery cell, which may deteriorate the battery life.

  The present invention has been made in view of the above background, and its object is to solve the above-described drawbacks of the prior art, and to charge a plurality of types of battery packs having battery cells of different sizes and accommodated in the battery pack. Another object of the present invention is to provide a charging device capable of setting an appropriate charging current or charging voltage corresponding to the type of the battery cell (unit cell).

  Another object of the present invention is to provide a charging device in which the charging device can obtain different determination signals depending on the types of battery cells accommodated in the battery pack.

  Still another object of the present invention is to provide a charging device that can set the optimum charging current or charging voltage by determining the type of the battery cell on the charging device side within a short time after the start of charging. is there.

  Among the inventions disclosed in accordance with the present invention in order to solve the above problems, the characteristics of typical ones will be described as follows.

  According to one aspect of the present invention, there is provided a charging device having a control device capable of charging a battery pack including a battery pack in which a plurality of types of battery cells are connected in series or in parallel, the plurality of types of battery packs being 1st battery pack provided with the assembled battery which connected the battery cell of 18650 size, and 2nd battery pack provided with the assembled battery which connected the battery cell of 14500 size. The control device performs different charging control between the first battery pack and the second battery pack, and determines the first battery pack and the second battery pack based on the battery voltage or battery temperature during charging. .

  According to another aspect of the present invention, there is provided a charging device having a control device capable of charging a battery pack including a battery pack in which a plurality of types of battery cells are connected in series or in parallel, wherein the plurality of types of battery packs are A first battery pack including an assembled battery connected with 18650 size battery cells, and a second battery pack including an assembled battery connected with 14500 size battery cells. The charging is controlled so that the charging current is changed to the charging current corresponding to the first battery pack and the second battery pack after a predetermined time has elapsed since the charging of the second battery pack was started.

  According to another feature of the present invention, the first battery pack and the second battery pack are constituted by lithium ion battery cells, and the control device controls the battery with constant current control until the charging voltage reaches a predetermined value. The pack is charged, and after the charging voltage reaches a predetermined value, the battery pack is charged by constant voltage control, and the current value in constant current control is changed between the first battery pack and the second battery pack. The first battery pack and the second battery pack have battery type discrimination means for indicating the type of battery cell contained therein, and the control device discriminates the battery type having a different resistance value depending on the type of battery pack. The charging current or the charging voltage is controlled according to the result determined by the battery type determining means such as resistance. For this reason, it is preferable to previously store a set of charging current and charging voltage in accordance with the resistance value of the battery type discrimination resistor in the control device in a table.

  According to still another feature of the present invention, the control device detects the rising slope of the battery voltage or / and the battery temperature within a predetermined time after the start of charging to thereby detect the first battery pack or the second battery pack. Which is attached is determined, and the charging current or the charging voltage is controlled according to the determined result. The control device may store in advance a charging current value corresponding to the battery voltage or / and the inclination of the battery temperature. In addition, the control device starts charging the battery pack with a charging current that matches a battery cell having a large battery capacity, and the state in which the rising slope of the battery voltage or / and the battery temperature after the start of charging continues to exceed a specified value continues for a specified time. The charging current is switched for a small battery cell. In addition, the control device sets the charging current per battery cell to be smaller when charging the second battery pack than when charging the first battery pack. Furthermore, the control device sets the charging current per battery cell to be smaller when charging a plurality of series-type battery packs than when charging a plurality of parallel-type battery packs.

  According to the first aspect of the present invention, it is possible to charge a plurality of types of battery packs including battery cells having different sizes of 18650 and 14500 with a single charging device.

  According to the invention of claim 2, since different charge control is performed between the first and second battery packs, optimum charge is possible according to the type of the battery pack, and the cycle life of charge / discharge of the battery pack is reduced. Can provide a battery charger

  According to the invention of claim 3, since the control device determines whether the battery pack is the first battery pack or the second battery pack based on the battery voltage or battery temperature during charging, the control device determines the battery voltage or battery temperature during charging of the battery pack. Accordingly, it is possible to perform optimal charging, avoid an increase in voltage or temperature that would overload the battery cell, and more reliably prevent a decrease in battery life.

  According to the invention of claim 4, since the control device changes the charging current according to the first battery pack and the second battery pack after starting the charging, the charging that does not hinder the cycle life of the charging / discharging of the battery pack. Equipment can be provided.

  According to the invention of claim 5, when the control device charges with the constant current control and the constant voltage control, the current value in the constant current control is changed between the first battery pack and the second battery pack. On the other hand, it is possible to avoid an increase in voltage and temperature that would be overloaded, and to prevent a decrease in battery life.

  According to the sixth aspect of the present invention, since the battery type discriminating means indicating the type of the battery cell is provided inside, the charging device can identify the size of the battery of the attached battery pack.

  According to the invention of claim 7, since the set of the charging current and the charging voltage corresponding to the resistance value of the battery type discrimination resistor is stored in the charging device in advance in the table, the charging device can quickly obtain the optimum charging current or charging voltage. Can be set.

  According to the invention of claim 8, since the charging device detects the state of the battery cell included in the battery pack by detecting the inclination of the battery voltage or / and the battery temperature within a predetermined time after the start of charging. Even if the battery pack has no seed discrimination means, optimal charging control can be performed.

  According to the ninth aspect of the present invention, since the charging current corresponding to the inclination (change) of the battery voltage and the battery temperature is stored in the charging device in advance in the table, the charging device can quickly set the optimum charging current. it can.

  According to the invention of claim 10, since the charging is started with the charging current that matches the battery pack with the battery cell having a large battery capacity, the charging time can be shortened, while the battery voltage and the battery temperature are abnormally increased. Since the charging current is reduced when the operation continues, it is possible to avoid overloading the battery cell.

  According to the eleventh aspect of the invention, when the second battery pack is charged, the control device sets the charging current per battery cell to be smaller than when the first battery pack is charged. Therefore, it is possible to perform optimum charging according to the size of the battery cell.

  According to the invention of claim 12, when charging a battery pack of a plurality of series types, the charging current per battery cell is set to be smaller than when charging a battery pack of a plurality of parallel types. An appropriate charging current or charging voltage can be set corresponding to the type of connection.

  The present invention is particularly effective when applied to a battery pack charging apparatus composed of lithium ion secondary battery cells requiring protection measures against overcharge and overdischarge. The above and other objects, and the above and other features and advantages of the present invention will become more apparent from the following description of the present specification and the accompanying drawings.

It is a circuit diagram which shows the charging device which concerns on the Example of this invention. It is a figure for demonstrating the difference in the charge characteristic of a battery cell of 18650 size, and a battery cell of 14500 size. It is an operation | movement flowchart which performs constant current and constant voltage charge with the charging device which concerns on the Example of this invention. It is an operation | movement flowchart which performs constant current and constant voltage charge with the charging device which concerns on the 2nd Example of this invention. It is a figure for demonstrating the difference in the charge characteristic of the single battery cell which concerns on the 3rd Example of this invention, and two battery cells connected in parallel. It is an operation | movement flowchart which performs constant current and constant voltage charge with the charging device which concerns on the 4th Example of this invention. It is a figure which shows the relationship between the charging current in the case of charging with the charging device which concerns on the 5th Example of this invention, battery voltage, and battery temperature. It is an operation | movement flowchart which performs constant current and constant voltage charge with the charging device which concerns on the 5th Example of this invention. It is a figure which shows the dimension of the lithium ion battery used for an electric tool.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG. Initially, the structure of the charging device which concerns on the Example of this invention is demonstrated. FIG. 1 shows a circuit diagram of the charging device 200. In FIG. 1, the charging device 200 is configured such that a plurality of types of battery packs 2 that differ depending on the connection form of the battery cells 2 a can be charged by the same charging device 200. For example, one battery pack 2 that can be charged with a predetermined charging current or charging voltage set by the charging device 200 is a single battery cell 2a or an assembled battery in which a plurality of battery cells 2a are connected in series. The battery pack is configured (referred to herein as “one para” in the sense of one system when viewed in the parallel direction) for convenience of explanation. In addition, the other battery pack that can be charged by the charging device 200 includes at least two battery packs in which at least a pair of battery cells 2a are connected in parallel, or at least two battery cell arrays in which a plurality of battery cells 2a are connected in series. Is a battery pack of two paratypes (two types as seen in the parallel direction). Of course, three paratypes of two or more paratypes can be configured to be rechargeable. The battery cell 2a is composed of, for example, a lithium ion secondary battery cell. Depending on the size of the battery pack 2, the battery cell 2a uses a 18650 size lithium ion battery cell or a 14500 size lithium ion battery cell. Exists. According to the present invention, the charging device 200 can set the charging current or charging voltage of the plurality of types of battery packs 2 to an appropriate value according to the battery cell size and the connection form such as series or parallel. . In particular, by setting to an appropriate value according to the size of the battery cell (18650 size and 14500 size), the battery cell can be appropriately charged and the life reduction can be suppressed.

  The battery pack 2 includes battery type determining means for determining the number of cells or the connection form of the battery cells 2a in the first battery pack of one paratype or the second battery pack of two paratypes. The battery type discriminating means is constituted by a discrimination resistor 7 whose resistance value is changed according to the type of the battery pack 2, for example. Further, the battery pack 2 includes a temperature sensing element 8 that functions as a temperature detection sensor such as a thermistor disposed in contact with or close to the battery cell 2a in order to detect the battery temperature in the battery pack 2. In the charging apparatus 200 according to the present embodiment, the battery pack 2 includes two sets of 4S1P type having a nominal voltage of 14.4V in which four lithium ion battery cells 2a are connected in series and four battery cell arrays connected in series. The 4S2P type connected in parallel can be charged. Furthermore, as the battery pack 2, four 18650-sized lithium ion battery cells 2a connected in series and four 14500-sized lithium ion battery cells 2a connected in series are configured to be rechargeable. The battery cell discrimination resistor 7 is used to divide the DC voltage (stabilized DC voltage) Vcc from the battery type discrimination resistor 9, and the microcomputer 50 discriminates the battery type based on the detected voltage.

  The temperature sensing element 8 of the battery pack 2 is connected to a battery temperature detection circuit 80 including detection resistors 81 and 82 to which a DC voltage Vcc is supplied, and converts a temperature change of the resistance value into a voltage. Input to the A / D port 52. The positive terminal of the battery pack 2 is connected to a battery voltage detection circuit 90 including a voltage dividing circuit of a resistor 91 and a resistor 92.

  The charging device 200 is a device for charging the battery pack 2 using the AC power source 1, and the output is controlled by the rectifying and smoothing circuit 10 that rectifies the AC power source 1 and converts it into DC, and the output pulse from the MOSFET 22. Switching circuit 20 including a high-frequency transformer 21, a rectifying / smoothing circuit 30 that rectifies the output of the switching circuit 20 and converts the output to direct current of a predetermined voltage, a constant voltage power supply circuit 40, a charging voltage control circuit 100, and a charging current The circuit includes a control circuit 60, a charging current setting circuit 70, a battery temperature detection circuit 80, a battery voltage detection circuit 90, a display circuit 110, and a microcomputer 50 that controls them.

  The rectifying / smoothing circuit 10 includes a full-wave rectifying circuit 11 including a rectifying diode connected in a bridge and a smoothing capacitor 12, and full-wave rectifies the AC power source 1 such as a commercial AC power source. The switching circuit 20 includes a high-frequency transformer 21, a MOSFET (switching element) 22 connected in series to the primary winding of the high-frequency transformer 21, and a PWM for modulating the pulse width of the drive pulse signal applied to the gate electrode of the MOSFET 22. A control IC (switching control IC) 23 is provided.

  The drive power for the PWM control IC 23 is supplied from a rectifying / smoothing circuit (DC power supply circuit) 6. The rectifying / smoothing circuit 6 includes a transformer 6a, a rectifying diode 6b, and a smoothing capacitor 6c. A charging voltage control signal and a charging current control signal are input to the PWM control IC 23 via the charging feedback signal transmission means 5 made of a photocoupler. In addition, a charge control signal for controlling the start and stop of charging is input to the PWM control IC 23 via the charge control transmission means 4 comprising a photocoupler.

  The PWM control IC 23 controls the start and stop of the charging operation of the MOSFET 22 by the control signal supplied from the microcomputer 50 by the photocoupler (charge control transmission means) 4 and is supplied by the photocoupler (charge feedback signal transmission means) 5. By changing the drive pulse width supplied to the gate electrode of the MOSFET 22 according to the control signal, the ON time of the MOSFET 22 is controlled, and the output voltage of the rectifying and smoothing circuit 30 and the charging current of the battery pack 2 are adjusted. The rectifying / smoothing circuit 30 includes a rectifying diode 31, a smoothing capacitor 32, and a discharging resistor 33 connected to the secondary winding of the high-frequency transformer 21.

  The constant voltage power supply circuit 40 is provided to supply a stabilized DC voltage Vcc to various control circuits (including a detection circuit) such as the microcomputer 50 and the operational amplifiers 61 and 65. The constant voltage power supply circuit 40 is connected to the transformers 41a to 41c, the switching element 42 and the control element 43 constituting the switching power supply, the rectifying diode 44, the three-terminal regulator 46, and the input side of the three-terminal regulator 46. And a smoothing capacitor 47 connected to the output side of the three-terminal regulator 46, and outputs a constant voltage Vcc. A reset IC 48 for outputting a reset signal when the commercial power source 1 is turned on to the charging device 200 is connected to the constant voltage output side of the constant voltage power supply circuit 40.

  The control circuit device (microcomputer) 50 determines the battery temperature based on the output signal of the battery temperature detection circuit 80, determines the battery voltage based on the output signal of the battery voltage detection circuit 90, the charging current control circuit 60, and the charging voltage control circuit 100. It is provided for executing control signal output to the. Although not shown, the microcomputer 50 is a read only memory (ROM) that stores a control program of the CPU 51, data related to the battery type of the battery pack 2, and the like, in addition to a CPU (central processing unit) 51 that executes a control program. ), A random access memory (RAM) used as a work area for the CPU 51, a temporary data storage area, and the like, and a timer. The microcomputer 50 includes an A / D port 52 for converting an analog input signal detected by the battery type discrimination resistor 9, the battery voltage detection circuit 90, the battery temperature detection circuit 80, and the like into a digital output signal; An output port 51b for outputting a control signal to the voltage control circuit 100, an output port 51a for outputting a control signal for the charging control transmission means 4 and a charging state display circuit 110 described later, and a reset signal for the reset IC 48 And a reset input port 53 for inputting.

  The charging current control circuit 60 includes operational amplifiers (operational amplifiers) 61 and 65, input resistors 62 and 64 of the operational amplifiers 61 and 65, feedback resistors 63 and 66 of the operational amplifiers 61 and 65, a diode 68, and a current limiting resistor 67. And an operational amplifier circuit composed of an output circuit. The input stage of the charging current control circuit 60 is connected to the current detection resistor 3 for detecting the charging current of the battery pack 2. Further, as described above, the output stage controls the PWM control IC 23 via the charging feedback signal transmission means 5 comprising a photocoupler. A charging current setting circuit 70 is connected to one input terminal (+) of the operational amplifier (voltage comparator) 65. On the other hand, the output voltage of the operational amplifier 61 is input to the A / D port 52 to monitor the charging current value, and the charging current value is measured by the microcomputer 50. The microcomputer 50 also measures a decrease in the current value at the time of full charge, based on the output of the operational amplifier 61.

  The charging current setting circuit 70 is provided for setting the charging current to a predetermined current value according to the battery type of the battery pack 2. The charging current setting circuit 70 has a series circuit (voltage dividing circuit) of a resistor 71 and a resistor 72 connected to the stabilized DC voltage Vcc, and a resistor 73 connected in parallel to the resistor 72. A desired charging current is set by supplying a reference voltage corresponding to a different charging current to the input terminal (+) of the operational amplifier 65 for voltage comparison. According to the present embodiment, two charging current modes can be set by connecting the resistor 73 in parallel to the resistor 72 based on the operation of the microcomputer 50. For example, when the microcomputer 50 controls the resistor connected in series to the resistor 71 as the resistor 72 alone, the first charging current is set, and the resistor connected in series to the resistor 71 is a parallel connection resistor of the resistor 72 and the resistor 73. When controlled, the second charging current is set. In this case, the first charging current is smaller than the second charging current.

  The charging current control circuit 60 inverts and amplifies the voltage drop based on the charging current flowing through the current detection resistor 3 by the resistors 62 and 63 and the operational amplifier 61, and the output voltage and the charging current value set by the charging current setting circuit 70. Is amplified by an operational amplifier 65 functioning as a voltage comparator, and the PWM control IC 23 is fed back via the charge feedback signal transmission means 5 to control the switching operation of the MOSFET 22. To do. That is, the MOSFET 22 gives an output pulse with a narrowed pulse width to the high-frequency transformer 21 when the charging current flowing through the current detection resistor 3 is larger than the predetermined charging current, and conversely when the charging current is smaller than the predetermined charging current. A pulse having a wider pulse width is applied to the high-frequency transformer 21. Thus, the rectifying / smoothing circuit 30 smoothes the DC voltage corresponding to the predetermined charging current, and holds the charging current of the battery pack 2 at the predetermined current set by the charging current setting circuit 70. In other words, the current detection resistor 3, the charging current control circuit 60, the charging feedback signal transmission means 5, the switching circuit 20, and the rectifying / smoothing circuit 30 are set so as to have a set charging current value set by the charging current setting circuit 70. The charging current flowing through the pack 2 is controlled.

  The charging voltage control circuit 100 is charging voltage control means, and includes resistors 101, 103, 105-108, a potentiometer 102, a capacitor 104, a shunt regulator 116, a rectifier diode 117, and an FET 118. The charging voltage is determined so that the series resistance of the resistor 101 and the potentiometer 102 and the divided value of the resistor 105 and the resistor 106 become the reference value of the shunt regulator 116. For example, the value determined by the series resistance of the resistor 101 and the potentiometer 102 and the resistor 105 is a value for charging a 4-cell lithium-ion battery, a parallel resistance of the resistor 105 and the resistor 106 (a parallel resistance by turning on the FET 118) ) Is determined as a value for charging a 5-cell lithium ion battery.

  The display circuit 110 is a display means for displaying the state of charge of the battery pack 2 and includes an LED 111 including a red LED (R) and a green LED (G), and current limiting resistors 112 and 113 of the LEDs. . According to this embodiment, when a high signal is output from the output port 51a of the microcomputer 50 to the resistor 112, the red LED (R) is turned on to display the state before charging, and the resistor 113 is displayed from the output port 51a of the microcomputer 50. When a high signal is output, the green LED (G) is lit and the state after the end of charging is displayed. Further, when a high signal is output from both the output ports 51a of the microcomputer 50 to the resistor 112 and the resistor 113, the red LED (R) and the green LED (G) are turned on at the same time. Is displayed.

  With the above configuration, even in the case of a battery pack having the same number of cells in a series of battery cells connected in series, appropriate charging is performed from the viewpoint of the battery life according to whether the battery cell is 18650 size or 14500 size. be able to. For example, in the case of the 14500 size, the charging current of the charging current control circuit 60 can be set small by supplying a low signal from the output port 51b of the microcomputer 50 to the input terminal of the resistor 73.

Next, the difference in charging characteristics between the 18650 size battery cell and the 14500 size battery cell will be described with reference to FIG. In this graph, the horizontal axis represents elapsed time (unit: min), and the vertical axis represents voltage (unit: V), temperature (unit: ° C), and current (unit: A). The charging target is a single cell of 18650 and a single cell of 14500, but the same graph is obtained even in a battery pack in which a plurality of battery cells are connected in series. Here, when charging a battery cell of 18650 size, charging is performed by constant current control from time 0 to time t ₁ , and when the battery voltage reaches the predetermined value V _m or the battery temperature reaches the predetermined value T _m , the time switching from constant current charging to the constant voltage charging to charge at t _2. Then, the charging current at the time t ₃ to terminate the charging when it reaches the following charge termination current I _E. In normal charging, charging is started with a charging current I ₁ that matches the battery cell having the larger battery capacity, that is, the battery cell of 18650 size. Here, when charging directly 14500 size battery cells in the charging device for charging the battery cells of 18650 size, between time 0 and time _{t 1,} as compared with the battery temperature 161 of the battery cell of 18650 size, the 14500 size Like the battery temperature 162 of a battery cell, it will rise rapidly especially as shown by the arrow 162a. In addition, the battery voltage also rapidly increases as shown by the arrow 172a of the battery voltage 172 of 14500 size compared to the battery voltage 171 of the battery cell of 18650 size. When the time t ₁ after charging the charging voltage remains at I _1, rise and rise in the battery temperature further battery voltage will happening. This is because the 14500 size battery cell having a smaller size has a larger internal resistance than the 18650 size battery cell having a larger size. Therefore, when charging is performed with the same charging current I ₁ , the battery voltage rises and the battery temperature changes (rises) increases.

In this embodiment, after a predetermined time t _{1 has} elapsed from the start of charging (after the initial charging has elapsed), the charging current is switched to I ₂ suitable for a 14500 size battery cell as shown by the dotted line 152 to continue charging. did. When the charging current is decreased from I ₁ to I ₂ at time t ₁ , the battery voltage 172b decreases at that moment, but continues to increase again and reaches the terminal voltage V _m for constant current charging at time t ₂ . On the other hand, the battery temperature 162 gradually increases although the increase curve decreases. When terminal voltage V _m or terminal temperature T _m is reached at time t ₂ , switching to constant voltage control is performed, but the charging voltage at that time is V _m , and the same applies to 18650 size battery cells and 14500 size battery cells. . The charge termination current _IE may be the same value for the 18650 size battery cell and the 14500 size battery cell. However, the termination voltage V _m or the termination temperature T _m is preferably set to an optimum value depending on the characteristics of the battery cells accommodated in the battery pack 2. Further, the charge end current _IE may be changed according to the change of the charge current. In this way, by setting whether the battery cell is 18650 size or 14500 size within a predetermined time after the start of charging, the setting of the current value in the constant current control during the time t _{1 to} t ₂ is changed. Combined optimum charge control can be performed.

  Next, an operation flowchart in the case where constant current / constant voltage charging is performed by the charging apparatus according to the present embodiment will be described with reference to FIG. In the control of this embodiment, the microcomputer 50 can determine the number of battery cells included in the battery pack 2 or the rated voltage based on a signal from the determination resistor 7 or the battery voltage detection circuit 90, but the battery included in the battery pack 2 It is an example of charge control when it is unknown whether the cell is 18650 size or 14500 size. When the battery temperature gradient or the battery voltage gradient is equal to or higher than a predetermined value after a predetermined time has elapsed since the start of charging, the charging device 200 determines that the battery has a size of 14500, and when it is equal to or lower than the predetermined value, the 18650 size. It is determined that the battery is an appropriate battery, and each battery is optimally charged.

Charging device 200 begins to charge with a charging current _{I 1} at time 0, the microcomputer 50 cell temperature at that time (161, 162), to monitor the degree of increase of the battery voltage (171, 172). At this time, if it is determined that the rising slope of the battery temperature is large at the time indicated by the arrow 172a (time t ₁ ), or if it is determined that the rising slope of the battery voltage is large, the charging current is decreased from I ₁ to I ₂ . Battery voltage at the time t ₂ is switched to the constant voltage control from constant current control to reach a predetermined value V _m, the charging current to terminate the charging by the charging termination current I time t ₃ when reaching the _E. Hereinafter, a specific operation flow will be described.

  FIG. 3 is an operation flowchart for performing constant current / constant voltage charging by the charging apparatus according to the first embodiment of the present invention. First, when a power cord (not shown) of the charging device is connected to a commercial power outlet, it is determined whether or not the battery pack 2 for charging is attached to the charging device (step 181). Here, before the battery pack 2 is mounted, the red LED (R) of the display circuit 110 is lit to display the state before charging. Whether the battery pack 2 is attached to the charging device can be determined by the microcomputer 50 using the outputs of the battery temperature detection circuit 80 and the battery voltage detection circuit 90.

  When it is determined that the battery pack 2 is attached (in the case of YES), the battery type determination resistor 9 determines the number of battery cells connected in series (step 182). If the battery pack 2 is not provided with the cell number discrimination resistor 7, the battery voltage as the output of the battery voltage detection circuit 90 is divided by the voltage per unit battery cell (for example, 3.6V). The number of cells can be determined. Next, a charging voltage corresponding to the number of battery cells (battery voltage) is set by the charging voltage control circuit 100 (step 183).

In step 184, it initiates a current charging by setting a charge current to I _1. Next, the microcomputer 50 detects the battery voltage as well as the battery voltage (steps 186 and 187). Then, the process returns to step 186 again, and the detection of the battery voltage and the battery temperature is repeated until a predetermined time has elapsed. When a predetermined time is detected in step 188, that is, when an interval time for executing the subsequent steps 189 and 190 has elapsed, a battery temperature gradient is obtained from the detected plurality of battery temperature measurement values, and the battery temperature gradient is greater than or equal to the predetermined value. Whether it exists is detected (step 189). Further, a battery voltage gradient is obtained from the detected plurality of battery voltage measurement values, and it is detected whether the battery voltage gradient is a predetermined value or more (step 190). Here, the battery temperature gradient or the battery voltage gradient is greater than or equal to a predetermined value because the temperature rise (slope) is large as indicated by the arrow 162a in FIG. 2 due to the large internal resistance of the battery cell, or the arrow in FIG. since in the sense that the voltage rises as the 172a (inclination) is large, go to step 192, it is determined that the battery cells included in the battery pack 2 is the size 14500, a constant voltage charging current to I ₂ Set and proceed to step 194 (step 193). Note that the processing of steps 189 and 190 may be reversed.

Next, the microcomputer 50 determines whether the voltage of the battery pack 2 has reached the threshold value (V _m ) for switching to constant voltage charging. If not, the microcomputer 50 performs constant current charging with the set charging current until the step threshold value is reached. Continue (step 194). If it is determined to have reached the threshold (Vm) in step 194, charging switch to constant voltage charging at a voltage V _m. Next, it is determined whether the charging current has reached the charging termination current _IE. If not, constant voltage charging is continued, and if it has reached, charging is terminated (steps 196, 197). Thereafter, in step 198, it is determined whether or not the battery pack 2 has been removed from the charging device 200, and if removed, the process returns to step 181.

  As described above, according to the first embodiment, when the battery temperature gradient or the battery voltage gradient is equal to or higher than a predetermined value after a predetermined time has elapsed after starting charging, the battery of 14500 size is equal to or lower than the predetermined value. Can be determined to be 18650 size batteries, and each can be charged optimally. The internal resistance varies depending on the size of the battery cell, and the size of the battery cell can be determined using this internal resistance. Therefore, even if the battery pack does not have a resistance for determination, optimal charging can be performed. it can. That is, the number of cells can be determined from the battery voltage and the size of the battery cell can be determined from the difference in the internal resistance of the battery cell without providing the battery type determination resistor 9 (the determination resistor 7). Therefore, it is possible to set an optimal charging current for the battery pack (battery cell) and to suppress a reduction in the life of the battery cell.

  Next, an operation flowchart in the case of performing constant current / constant voltage charging by the charging device when the battery pack 2 includes the determination resistor 7 will be described with reference to FIG. The procedure described in this flowchart can be realized by the microcomputer 50 (see FIG. 1) executing a computer program. In this control procedure, the microcomputer 50 determines whether the battery size accommodated in the battery pack 2 is 18650 or 14500 using the output from the determination terminal that is the output of the determination resistor 7 included in the battery pack 2, and is optimal. Charge control is performed.

  First, when a power cord (not shown) of the charging device is connected to a commercial power outlet, it is determined whether or not the battery pack 2 for charging is attached to the charging device (step 201). Here, before the battery pack 2 is mounted, the red LED (R) of the display circuit 110 is lit to display the state before charging. The microcomputer 50 can determine whether or not the battery pack 2 is attached to the charging device using outputs of the battery temperature detection circuit 80, the battery type determination resistor 9, and the battery voltage detection circuit 90.

  When it is determined in step 201 that the battery pack 2 is mounted (in the case of YES), the number of battery cells connected in series is determined by the battery type determination resistor 9 (step 202). Next, a charging voltage corresponding to the number of battery cells connected in series by the charging voltage control circuit 100 is set (step 203). In this embodiment, the battery pack is described as a battery pack having 4 cells and 5 cells. For example, the number of battery cells connected in series is 1 cell, 2 cells, 3 cells, 4 cells and 5 cells, or The above-described lithium ion battery pack may be charged. In this case, a plurality of charging voltages may be set by the charging voltage control circuit 100. In the next step 204, it is determined by the battery type discrimination resistor 9 whether or not the battery cell included in the battery pack 2 is a 18650 battery.

  There are two types of battery packs 2 that can be charged by the charging device of this embodiment: a battery cell composed of a 18650 size battery and a battery cell composed of a 14500 size battery. The discrimination by the battery type discrimination resistor 9 corresponds to the value of the discrimination resistor 7 provided in the battery. For example, if the value of the discrimination resistor 7 is Ra, a two-cell 18650 size battery pack (generally referred to as a 2S2P type), and if the value is Rb, a two-cell 14500 size battery pack ( In general, what is referred to as 2S1P type), if the value is Rc, 3 cell 18650 size battery pack (3S2P type), if the value is Rd, 3 cell 14500 size battery pack (3S1P type), Re 4 cell 18650 size battery pack (4S2P type), Rf value 4 cell 14500 size battery pack (4S1P type), Rg value 5 cell 18650 Size battery pack (5S2P type), if the value is Rh, battery pack of 5500 14500 size It discriminates in accordance with the respective values such click (5S1P type). In this embodiment, two types of battery cells included in the battery pack 2 are identified as 18650 size and 14500 size, and these are determined. However, the type and size of the battery cells used in the battery pack 2 are However, the present invention is not limited to this and may be other. The above-mentioned S means the number of battery cells connected in series, and P means the number of battery cells connected in parallel.

In step 204, if the battery cell used in the battery pack 2 is a size 18650, initiate the setting to the current charging the charge current _{I 1} (step 205 and 207), if the battery cell size 14500 is charged The current is set to I ₂ and current charging is started (steps 206 and 207). In other words, the 14500 size battery pack normally has an allowable current value about half that of the 18650 size battery pack, so the charging current is changed to I ₂ from the beginning of charging accordingly. That is, since the charging current is set before the start of charging according to the size of the battery pack, the battery is already charged with the charging current according to the battery pack for a predetermined time (t _{0 to} t ₁ ) in FIG. Next, at step 207, a low signal is output from the output port 51a of the microcomputer 50 to start charging to the photocoupler 4, and the PWM control IC 23 is put into an operating state. Thereby, charging is started. Further, a high signal is output from the output port 51a of the microcomputer 50 to the display circuit 110, and the LED 111 is lit in orange to indicate that charging is in progress.

In step 207, after charging is started, the potential detected by the current detection resistor 3 is inverted and amplified by the operational amplifier 65 and taken into the A / D port 52 of the microcomputer 50 to monitor the charging current. When the charging voltage of the battery pack 2 rises with constant current charging and reaches a constant voltage charging section (for example, the charging voltage (battery voltage) is 4.10 V), the charging is switched from constant current charging to constant voltage charging. Decreases from a constant current value, but detects whether or not the charging current has decreased below a predetermined value, and determines whether or not the battery has been fully charged. After the charging current is determined to full charge becomes less than a predetermined value decreasing at time t _3, and outputs a high signal from a port leading to the photocoupler 4 at the output port 51a, a PWM control IC23 to stop state (step 209). At the same time, a high signal is output from the output port 51a of the microcomputer 50 to the resistor 113 of the display circuit 110, the green LED (G) is turned on, and the state after charging is displayed. Thereafter, in step 210, it is determined whether or not the battery pack 2 has been removed from the charging device 200. If the battery pack 2 has been removed from the charging device 200 (YES), the process returns to step 201.

  As described above, according to the present embodiment, the 18650-size battery cell and the 14500-size battery cell are provided with different discriminating elements (the discriminating resistor 7), and the difference between the discriminating elements is discriminated on the charging device 200 side. Based on the result, optimum charge control is performed. Accordingly, it is possible to provide the charging device 200 that can optimally charge both the 14500 size battery and the 18500 size battery, and the charging current of the battery pack that is used with a severe load current like a cordless type electric tool. The life can be remarkably improved by lowering the size compared to the 18650 size. Moreover, since it can set to the optimal charging current before a charge start, it can charge from the charge initial stage with the optimal charging current, and can suppress the lifetime reduction of a battery cell.

Next, the difference in charging characteristics between the case where the unit of 14500-size battery cells is connected in parallel (2 para) and the case of series connection (1 para) will be described with reference to FIG. When 14500 size battery cells are connected in parallel, the same characteristics as 18650 size battery cells are exhibited. In other words, in the case of 14500-size battery cells connected in series (1 parameter), when the charging current is initially charged with current I ₁ as shown by the dotted line 252 and switched to I ₂ after a predetermined time has elapsed, the battery voltage becomes the dotted line 272. The battery temperature becomes as indicated by a dotted line 262. When the battery cells are connected in parallel, even if charging is started with a current I ₁ at a predetermined time, the battery voltage has a moderate rise rate as shown by a solid line 271 and the battery temperature also has a gentle rise curve as shown by a solid line 261. next, it is possible to continue charging without changing the constant current charging current I _1. Therefore, in the third embodiment, not only whether the battery size included in the battery pack 2 is 18650 size or 14500 size, but whether it is 14500 size, it is determined whether it is connected in series (1 parameter) or parallel connection (2 parameters or more). The charging current is set according to the determination result.

In the case of the battery pack 2 that does not include the discrimination resistor (discrimination element) 7, as in the first embodiment (FIG. 3), the battery voltage detection circuit 90 determines the number of cells and sets the output voltage. (step 182, 183) to start charging the charging current as _{I 1} (step 184, 185). After the start of charging, the battery voltage and the battery temperature are detected (steps 186 and 187). After a predetermined time (t _{0 to} t ₁ ) after the start of charging, whether or not the increase in the battery voltage or the battery temperature is equal to or higher than a predetermined value is determined. Judgment is made (steps 189 and 190). When the battery voltage gradient or the battery temperature gradient is greater than or equal to a predetermined value, the charging current is changed by determining that the battery pack is one-para connected (steps 192 and 193). In step 190, in the case of a two-parametric battery pack, the internal resistances of the battery cells are connected in parallel and the resistance value is halved, so that the rise in battery voltage and battery temperature is moderate. Therefore, it is possible to discriminate between battery packs of 2-para connection and 1-para connection. Thus, 2 if the battery pack para connection, the initial charging current charging characteristic (battery voltage gradient, the battery temperature gradient) be continued charging in I ₁ because is not abnormal (abnormal gradient), the reduction of the service life of the battery cell There is no cause. Note that constant voltage control and full charge control are the same as those in the first embodiment, and are therefore omitted.

  On the other hand, FIG. 6 is an operation flowchart for performing constant current / constant voltage charging by the charging device according to the fourth embodiment of the present invention in the battery pack 2 provided with the discrimination resistor 7. First, when a power cord (not shown) of the charging device is connected to a commercial power outlet, it is determined whether or not the battery pack 2 for charging is attached to the charging device (step 301). When it is determined in step 301 that the battery pack 2 is mounted (in the case of YES), the battery type determination resistor 9 determines the number of battery cells connected in series and in parallel (step 302). Next, a charging voltage corresponding to the number of battery cells is set by the charging voltage control circuit 100 (step 303).

In step 304, when 2 p of battery cells 14500 size used in the battery pack 2 starts current charging by setting a charge current to _{I 1} (step 305, 307), if the battery cell is 1 para Then, the charging current is set to I ₂ to start current charging (steps 306 and 307). That is, even when charging the same 14500 size battery pack, the charging current is changed in accordance with one parameter or two parameters. In FIG. 5, the section of the predetermined time (t _{0 to} t ₁ ) at the beginning of charging becomes unnecessary, and in step 307 from the initial stage of charging, switching to constant voltage charging is performed after constant current charging, and the charging current is below a certain predetermined value. If it is decreased, charging is terminated as full charge (steps 308 and 309). Thereafter, in step 310, it is determined whether or not the battery pack 2 has been removed from the charging device 200. If the battery pack 2 has been removed from the charging device 200 (YES), the process returns to step 301.

  As described above, according to the fourth embodiment, a different determination element (determination resistor 7) is provided for each of the 1-para-connection battery cell and the 2-para-connection battery cell, and the difference between the determination elements is determined by the charging device 200. The optimal charging control is performed based on the result. Thereby, even if it is the same voltage, the charging device 200 which can optimally charge the battery pack 2 from which the arrangement | sequence of a battery cell differs can be provided. In addition, as in the second embodiment, since the type of battery (the number of battery cells connected in series / parallel) is determined by the determination element, the charging current can be set before the start of charging. It can be charged from the beginning of charging.

  Next, constant current / constant voltage charging according to a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a diagram illustrating the relationship between the charging current, the battery voltage, and the battery temperature when charging is performed by the charging device according to the fifth embodiment of the present invention. The horizontal axis represents time (min), and the vertical axis represents battery voltage (V), battery temperature (° C.), and charging current (A) at that time. In the control of the fifth embodiment, the microcomputer 50 can determine the number of battery cells included in the battery pack 2 or the rated voltage, but the battery cells included in the battery pack 2 are 18650 size, 14500 size, or 14500 size. This is an example of charging control when it is unclear whether the first connection or the second connection. When the battery temperature gradient or the battery voltage gradient is equal to or higher than a predetermined value after a predetermined time has elapsed after starting charging, the charging device 200 determines that the battery is a 14500 size battery, and 18650 size when the battery temperature gradient is lower than the predetermined value. Battery (or 2500 connection of 14500 size) and optimal charging is performed respectively.

The charging device 200 starts charging with the charging current I ₁ at time 0, and the microcomputer 50 monitors the increase degree of the battery voltage 391 at that time. At this time, if it is determined that the rising slope of the battery voltage 391 is large at the time indicated by the arrow 391a (time t ₁₁ ), the charging current is decreased from I ₁ to I ₂ . Next, the microcomputer 50 again returns the charging current to _{I 1} when small time _{t 12} as slope arrow 391b of the battery voltage. However, after this, if it is determined that the rising slope of the battery voltage 391 is large at the time indicated by the arrow 391c (time t ₁₃ ), the charging current is decreased from I ₁ to I ₂ . In this way, constant current charging is performed while alternately changing the charging current between I ₁ and I ₂ , switching to constant voltage charging at time t ₁₆ , and charging at time t ₁₇ when the charging current becomes equal to or lower than the predetermined charging current. Terminate. Note that the charging current may be switched according to not only the battery voltage gradient but also the battery temperature gradient or both.

  FIG. 8 is an operation flowchart for performing constant current / constant voltage charging by the charging apparatus according to the fifth embodiment of the present invention. First, when a power cord (not shown) of the charging device is connected to a commercial power outlet, it is determined whether or not the battery pack 2 for charging is attached to the charging device (step 401). If it is determined that the battery pack 2 is attached (in the case of YES), the battery type determination resistor 9 determines the number of battery cells connected in series (step 402). Next, the charging voltage control circuit 100 sets a charging voltage corresponding to the number of battery cells connected in parallel (step 403). It is assumed that the battery type determination resistor 9 determines the number of cells, and the resistor 9 cannot determine the size of the battery cell and the number of parallel connections. This determination is made from the battery voltage gradient or the battery temperature gradient.

In step 404, it initiates a current charging by setting a charge current to I _1. Next, the microcomputer 50 detects the battery voltage as well as the battery voltage (steps 406 and 407). Then, the process returns to step 406 again, and the detection of the battery voltage and the battery temperature is repeated until a predetermined time has elapsed. When a predetermined time is detected in step 408, that is, when an interval time for executing the subsequent steps 409 and 410 has elapsed, a battery temperature gradient is obtained from a plurality of detected battery temperature measurement values, and the battery temperature gradient is greater than or equal to a predetermined value. Whether it exists is detected (step 409). Further, a battery voltage gradient is obtained from the detected plurality of battery voltage measurement values, and it is detected whether the battery voltage gradient is equal to or greater than a predetermined value (step 410). Here, the battery voltage gradient being equal to or greater than the predetermined value means that the voltage rise is large as indicated by an arrow 391a in FIG. 7, so the process moves to step 412 and the battery cells included in the battery pack 2 are moved. 14500 is the size, or it is determined that a 1 para 14500 size, the process proceeds to the constant-voltage charging current to step 414 to set _{I 2} (step 413). Similarly, the battery temperature gradient, because when the temperature rises above a predetermined value is when the temperature rise is large, sets the charging current I ₂ proceeds to step 414 (step 413).

Next, the microcomputer 50 determines whether or not the voltage of the battery pack 2 has reached the threshold value (V _m ) for switching to constant voltage charging. If not, the microcomputer 50 returns to step 406 (step 414). If it is determined in step 414 that the threshold value (V _m ) has been reached, charging is performed by switching to constant voltage charging at the voltage V _m . Next, it is determined whether or not the charging current has reached the charging termination current _IE. If not, constant voltage charging is continued, and if it has reached, charging is terminated (steps 416 and 417). Thereafter, in step 418, it is determined whether or not the battery pack 2 has been removed from the charging device 200. If the battery pack 2 has been removed, the process returns to step 401.

As described above, according to the fifth embodiment, when the battery temperature gradient or the battery voltage gradient is equal to or higher than a predetermined value after a predetermined time has elapsed after starting charging, the battery of 14500 size is equal to or lower than the predetermined value. Is determined to be a parallel connection of 18650 size batteries or 14500 size batteries, and each can be charged optimally. In addition, according to the fifth embodiment, the interval (up to time t ₁₆₎ that is performing constant-current charging control is constantly and compared with the battery voltage gradient or the battery temperature gradient with a predetermined value. With this control, in the case of a 14500-size battery cell, the charging current is temporarily set small from I ₁ to I ₂ at the beginning of charging, but the charging current is changed according to the subsequent charging characteristics (battery voltage gradient, battery temperature gradient). I ₂ is returned to I ₁ . Similarly, in the case of an 18650 size battery cell, the charging current is controlled according to the charging characteristics. In other words, the charging current is changed according to the battery cell at the initial stage of charging, but during the subsequent charging, the charging current is changed according to the charging characteristics regardless of the size (number of parallel connections) of the battery cell. Yes. Therefore, it is possible to shorten the charging time while suppressing deterioration of the battery cell.

  As described above, according to the present invention, in a charging device for charging a lithium ion battery pack including one or a plurality of lithium ion secondary battery cells, the size of the battery cells included in the battery pack, serial connection, and parallel connection An appropriate charging current or charging voltage can be set corresponding to Thereby, the charging device which does not inhibit the cycle life of charging / discharging of a battery pack can be provided.

  The invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. . For example, although the case where a lithium ion secondary battery is used as the battery cell has been described, the present invention can also be applied to nickel hydride batteries and other secondary batteries having different battery cell connection forms. Further, the charging method is not limited to the constant current / constant voltage charging method, and can be applied to a constant current charging method charging device. Furthermore, the battery type discriminating means indicating the type of the battery pack can use mechanical or electrical discriminating means other than resistance. For example, if the battery pack is provided with a protrusion corresponding to the battery type on the outer shape of the battery pack and a battery pack of 14500 size is set in the charging device, the elastic protrusion of the battery pack receiving portion formed on the charging device side is retracted. Moreover, in the case of 18650 size, it can be set as the external shape which detects a battery type mechanically so that it may not retract.

  Moreover, the charging device can be applied not only to two different sizes but also to battery cells of other sizes. Further, when the 18650 size battery cell deteriorates, the battery voltage gradient and the battery temperature gradient at the initial stage of charging may be steeper than those of the normal cell, and the charging behavior may be similar to that of the 14500 size battery cell. Therefore, when there is no discriminating element and the type of the battery cell is discriminated from the charging characteristics (battery voltage gradient, battery temperature gradient), it is difficult to discriminate the 14500 size battery cell from the deteriorated cell. However, since the deteriorated battery cell is easily damaged when it is continuously charged with a large current, it is preferable to charge the battery cell with a small charge current. In other words, it is not necessary to distinguish between 14500-size battery cells and deteriorated cells, and if the gradient at the beginning of charging is steep, the charge current is reduced to reduce deterioration of 14500-size battery cells and further deterioration of deteriorated cells. Can be suppressed.

DESCRIPTION OF SYMBOLS 1 AC power supply (commercial power supply) 2 Battery pack 2a Battery cell 3 Current detection resistor 4 Charge control transmission means (photocoupler)
5 Charging feedback signal transmission means (photocoupler)
6 Rectifier Smoothing Circuit 6a Transformer 6b Rectifying Diode 6c Smoothing Capacitor 7 Discriminating Resistor 8 Temperature Sensing Element 9 Battery Type Discriminating Resistor 10 Primary Side Rectifier Smoothing Circuit 11 Full-wave Rectifier Circuit 12 Smoothing Capacitor 20 Switching Circuit 21 High Frequency Transformer 22 MOSFET
23 PWM control IC (switching control IC)
30 Secondary-side rectifying and smoothing circuit 31 Rectifying diode 32 Smoothing capacitor 33 Discharge resistor 40 Constant voltage power supply circuits 41a, 41b, 41c Transformer 42 Switching element 43 Control element 44 Rectifying diode 45 Smoothing capacitor 46 Three-terminal regulator 47 Smoothing capacitor 48 Reset IC 50 Microcomputer 51 CPU 51a Output port 51b Output port 52 A / D port 53 Reset input port 60 Charging current control circuit 61, 65 Operational amplifiers 62, 63, 64, 66, 67 Resistance 68 Diode 70 Charging current setting Circuit 71-73 Resistance 80 Battery temperature detection circuit 81, 82 Detection resistance 90 Battery voltage detection circuit 91, 92 Detection resistance 100 Charging voltage control circuit 101-103, 105-108 Resistance 102 Potentiometer 104 Capacitor 110 (charging state) display circuit 111 display means (LED)
112, 113 Current limiting resistor
114, 115, 116, 117, 119 Resistor 116 Shunt regulator 117 Rectifier diode 118 FET 120 Resistor 121 Diode 122 Shunt regulator 140 Charging power supply circuit 161, 162 Battery temperature 172 Battery voltage 200 Charging device 391 Battery voltage _IE Charging termination current T _m Predetermined value (termination temperature) V _m Predetermined value (termination voltage)

Claims (12)

A charging device having a control device capable of charging a battery pack including a battery pack in which a plurality of types of battery cells are connected in series or in parallel,
The plurality of types of battery packs include a first battery pack including an assembled battery connected with 18650 size battery cells, and a second battery pack including an assembled battery connected with 14500 size battery cells. Charging device.   The charging device according to claim 1, wherein the control device performs different charging control for the first battery pack and the second battery pack.   The charging device according to claim 2, wherein the control device discriminates the first battery pack and the second battery pack based on a battery voltage or a battery temperature during charging.   The control device changes the charging current according to the first battery pack and the second battery pack after a predetermined time has elapsed after starting charging the first battery pack and the second battery pack. It controls as follows, The charging device as described in any one of Claim 1 to 3 characterized by the above-mentioned. The first battery pack and the second battery pack are constituted by lithium ion battery cells,
The controller is
Charge the battery pack with constant current control until the charging voltage reaches a predetermined value,
Charge the battery pack with constant voltage control after the charging voltage reaches a predetermined value,
5. The charging device according to claim 1, wherein a charging current value in the constant current control is changed between the first battery pack and the second battery pack. 6. The first battery pack and the second battery pack have battery type discrimination means for indicating the type of the battery cell contained therein,
The charging device according to claim 1, wherein the control device controls a charging current or a charging voltage according to a result determined by the battery type determining unit. The battery type discrimination means comprises a battery type discrimination resistor having a different resistance value depending on the type of the battery pack,
The charging device according to claim 6, wherein a set of a charging current and a charging voltage corresponding to a resistance value of the battery type determination resistor is stored in the control device in advance. The controller is
Whether the first battery pack or the second battery pack is installed is determined by detecting the inclination of the battery voltage or / and the battery temperature within a predetermined time after the start of charging. The charging device according to any one of claims 3 to 7, wherein a charging current or a charging voltage is controlled according to a result.   The charging device according to claim 8, wherein the control device stores in advance a charging current value corresponding to a slope of the battery voltage or / and battery temperature. The controller is
Start charging with a charging current that matches the battery pack with a battery cell with a large battery capacity,
The charging current is switched to a small battery cell when the state of the battery voltage or / and the battery temperature after the start of charging continues for a specified time or longer for a specified time or longer. The charging device according to 8 or 9.   The control device sets the charging current per battery cell to be smaller when charging the second battery pack than when charging the first battery pack. The charging device according to claim 7 or 8. 8. The control device according to claim 7, wherein when the plurality of series-type battery packs are charged, the charging current per battery cell is set smaller than when the plurality of parallel-type battery packs are charged. Or the charging device of 8.

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