JP2022011877A - Battery pack and electrical equipment system and electrical equipment body - Google Patents

Abstract

To provide a battery pack using more battery cells than required for a rated voltage by performing discharge control in a control unit.SOLUTION: In a battery pack that includes a positive electrode and a negative electrode, and connects n (for example, 12) battery cells connected in series, in a case in which the battery pack is connected to an electrical equipment body, when a total voltage of the plurality of battery cells is higher than a reference voltage Vs, PWM control is performed to limit the output voltage and output the output voltage from the positive and negative terminals, and when the output voltage is the reference voltage Vs or less, the limit is released and the voltage of the plurality of battery cells connected in series is used for output as it is. It is possible to avoid an early voltage drop phenomenon due to the use of a small cell, and it is possible to maintain a stable output.SELECTED DRAWING: Figure 6

Description

The present invention relates to a battery pack containing a plurality of battery cells in a case, an electric device system, and an electric device main body.

Cordless electrical devices that are driven by battery packs that use secondary batteries such as lithium-ion batteries are widely used. For example, in a hand-held electric tool in which a tip tool is driven by a motor, a battery pack containing a plurality of secondary battery cells is used as a power source, and a load device such as a motor is used by the electric energy stored in the battery pack. Drive. The battery pack is configured to be removable from the power tool body, and when the voltage drops due to discharge, the battery pack is removed from the power tool body and charged using an external charger. The technique of Patent Document 1 is known as an example of such a battery pack. In the battery pack of Patent Document 1, five cells of a lithium ion secondary battery having a nominal voltage (rated voltage) of 3.6 V are used as one cell unit, and power is supplied to the main body of the electric device in a parallel connection state of the two cell units. By supplying power, it operates as a battery pack having a rated voltage of 18V, and by supplying power to the main body of the electric device in a series connection state of two cell units, it operates as a battery pack having a nominal voltage (rated voltage) of 36V.

Japanese Unexamined Patent Publication No. 2019-21603

In cordless electric devices, a predetermined operating time is required and a predetermined output voltage is required, and along with the improvement of the performance of the secondary battery, the battery pack has been increased in voltage and output. Therefore, it has been practiced to increase the size of the battery cell used in the battery pack or to connect a plurality of cell units in parallel to increase the capacity. On the other hand, along with the demand for smaller and lighter power tools, there is also a demand for smaller battery packs. In other words, in both the conventional fixed output voltage type battery pack and the output voltage switching type battery pack, stable output voltage can be realized without enlarging the battery pack housing, and a long-life battery pack can be achieved. It is required to be realized.

The present invention has been made in view of the above background, and an object of the present invention is to provide a battery pack which is designed to have high output while being miniaturized.
Another object of the present invention is to provide a battery pack in which an early drop in output voltage is compensated for by using more battery cells than necessary for the rated voltage.
Another object of the present invention is to perform discharge control in the control unit of the battery pack, so that the voltage at the time of full charge can be used even if the voltage at the time of full charge is higher than the rated voltage of the main body of the electric device or the voltage at the time of full charge of the conventional battery pack. The purpose is to provide a high-power battery pack that enables it.
Another object of the present invention is to provide a battery pack for stabilizing the output voltage.
Another object of the present invention is to provide an electric device system using these battery packs, or an electric device main body to which the battery pack can be mounted.

The following is a description of typical features of the invention disclosed in the present application.
According to one feature of the present invention, there is a battery pack that can be connected to the main body of an electric device having a first rated voltage, and a plurality of battery cells in which n battery cells having a nominal voltage of the first voltage are connected in series. A terminal unit having a positive terminal and a negative terminal electrically connected to a plurality of battery cells, a control unit for controlling the discharge of the plurality of battery cells, and a plurality of battery cells and a positive terminal or a negative terminal. The output limiting unit provided in the output path between the terminals and configured to be able to limit the output voltage from the terminal unit is provided, and the total of the nominal voltages of the plurality of battery cells becomes higher than the first rated voltage. The output limiting unit is configured to limit the output voltage and supply the battery pack to the main body of the electric device when the battery pack is fully charged and connected to the main body of the electric device. Further, the output limiting unit is configured to release the limiting when the output voltage drops and supply the output voltage to the main body of the electric device. Also, when the battery pack is connected to the main body of the electric device, the output voltage is limited if the total voltage of multiple battery cells is higher than the reference voltage, and the limit is released if the total voltage is less than the reference voltage. I made it. The battery cells were connected in series with n cells, and the reference voltage was configured to be larger than the voltage when the battery cells were connected in series with n-1 cells.

According to another feature of the present invention, when the battery pack is connected to the main body of an electric device, if the remaining amount of a plurality of battery cells is larger than a predetermined threshold value, the output voltage is limited and the remaining amount is the threshold value. If it is less than the remaining amount, the restriction is lifted. Further, the voltage detection unit for measuring the voltage of the battery pack or the battery cell and the control unit limit the output voltage by operating the output limiting unit according to the measurement result of the voltage detection unit. Further, the output limiting circuit includes a semiconductor switching element, and the control unit PWM-controls the switching element to limit the effective value of the output voltage.

According to still another feature of the present invention, the battery pack is provided with a smoothing circuit between the positive electrode terminal and the negative electrode terminal and the output limiting circuit. Further, the output limiting circuit has a switch, and the switch determines whether the path is connected from the positive electrode of the battery cells connected in series to the semiconductor switching element or the path connected to the positive electrode terminal by bypassing the semiconductor switching element. It was configured to switch.

According to still another feature of the present invention, the positive electrode terminal has a first positive electrode terminal and a second positive electrode terminal, the negative electrode terminal has a first negative electrode terminal and a second negative electrode terminal, and n battery cells are connected in series. The first cell unit is connected to form a first positive electrode terminal and the first negative electrode terminal, and n battery cells are connected in series to form a second cell unit to form a second positive electrode terminal and a second positive electrode terminal. It was connected to the negative electrode terminal, a first output limiting circuit was provided corresponding to the first cell unit, and a second output limiting circuit was provided corresponding to the second cell unit.

According to still another feature of the present invention, the housing of the battery pack includes a lower case for accommodating the battery cell, a slot portion for accommodating a connection terminal including a positive electrode terminal and a negative electrode terminal, and an electric device main body or an external charging device. The lower case is configured to include an upper case in which a mounting portion for being connected to the battery is formed, and the lower case is provided with a partition for accommodating a plurality of battery cells in a plurality of areas. In addition, a circuit board connected to the connection terminal is provided, and the partition is located between the inner bottom surface of the lower case and the bottom surface of the circuit board in the vertical direction.

According to still another feature of the present invention, an electric device main body having a first rated voltage (for example, 36 V), a first battery pack having a voltage higher than the first rated voltage when fully charged, and a first battery pack. An electrical equipment system is realized that includes a second battery pack that corresponds to the rated voltage of 1 and has a voltage smaller than the voltage of the first battery pack when fully charged. The first battery pack has a cell unit in which a plurality of first battery cells having a first length (for example, 18350 size battery cells) are connected in series, and the second battery pack has a first length. It has a cell unit in which a plurality of second battery cells (for example, 18650 size battery cells) having a long second length are connected in series, and the number of the first battery cells accommodated is the capacity of the second battery cells. An electric device system with more than the number is realized. These limited output voltages correspond to the rated voltage of the second battery pack or the rated voltage of the electrical equipment body.

According to still another feature of the present invention, the battery pack is an electric device main body having a first rated voltage and having a voltage larger than the first rated voltage (for example, 36 V) when fully charged. A first battery pack having a cell unit in which a plurality of first battery cells having a length of 1 are connected in series can be attached and detached, and the first battery can be attached to and from the first rated voltage and is fully charged. A second battery pack having a voltage smaller than the voltage of the pack, and a cell in which a plurality of second battery cells having a second length longer than the first length and less than the first battery cell are connected in series. An electric device main body characterized in that a second battery pack having a unit can be attached and detached is realized.

According to the present invention, it is possible to provide a battery pack which is designed to have high output while being miniaturized.
Further, it is possible to provide a battery pack in which an early drop in output voltage is compensated for by using more battery cells than necessary for the rated voltage. In other words, by using a battery cell with a smaller size than before to reduce the size, and by using a battery cell with a larger number than the number of battery cells required for the rated voltage, the phenomenon of early voltage drop during use can be eliminated. I was able to avoid it.
Further, by performing discharge control in the control unit of the battery pack, it is possible to provide a high output battery pack that can be used even if the voltage at the time of full charge is higher than the rated voltage of the electric device main body. That is, if more than the required number of battery cells are connected in series to the battery pack, the voltage immediately after charging becomes too high, but the rated voltage is controlled by performing discharge control such as PWM control in the control unit of the battery pack. Appropriate voltage can be output along with.
Further, by performing the discharge control on the battery pack side, the user who uses the battery pack can use the battery pack of the present invention in the same way as the conventional battery pack without being aware of the difference from the conventional battery pack. Can be done. That is, the battery pack of the present invention can also be mounted on the main body of the electric device to which the conventional battery pack can be mounted.
Further, it is possible to provide a battery pack in which the output voltage of the battery pack is stabilized.
Further, it is possible to provide an electric device system using the battery pack of the present invention, or an electric device main body to which the battery pack can be mounted.

It is a perspective view of the battery pack 1 which concerns on embodiment of this invention. It is a wiring diagram of the battery cell of the battery pack 1 of this Example and the conventional example. It is a figure which showed the discharge characteristic of the battery pack using 10 and 12 battery cells. It is a figure for demonstrating the discharge characteristic of the battery pack of the conventional example, and the discharge control of the battery pack 1 by this Example. It is a block diagram which shows the internal circuit of the battery pack 1 of FIG. It is a figure which showed the discharge control of the battery pack 1 by this Example. It is a figure which shows the arrangement example of the battery cell in the battery pack, (A) is the conventional battery pack, (B) is the battery pack of this Example. It is a figure which shows another arrangement example of the battery cell in the battery pack 1 of this embodiment, (A) is an example which arranged the battery cell vertically, (B) is an example which arranged the battery cell in the horizontal direction. .. It is a perspective view of the lower case 8 alone of the battery pack 1 of this embodiment. It is a block diagram which shows the connection circuit of the battery pack 1 of this Example, and the electric apparatus main body 100. It is a flowchart which shows the output limitation procedure of a battery pack 1. It is a block diagram which shows the internal circuit of the battery pack 301 which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the connection circuit of the battery pack 301 and the electric apparatus main body 201A which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the connection circuit of the battery pack 301 and the electric apparatus main body 401 which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following figures, the same parts are designated by the same reference numerals, and the description of repetition will be omitted. In this specification, as an example of an electric device, a power tool operated by a battery pack will be used.

FIG. 1 is a perspective view of a battery pack 1 according to an embodiment of the present invention. The battery pack 1 connects a plurality of lithium ion battery cells having a nominal voltage (rated voltage) of 3.6 V (first voltage) in series, and outputs a DC current having a nominal voltage (rated voltage) of 36 V. The housing (case) of the battery pack 1 is made of a non-conductor material such as synthetic resin, and is formed of a lower case 8 and an upper case 2 that can be divided in the vertical direction. The upper case 2 is formed with a mounting mechanism in which two rail grooves 7a and 7b are formed for mounting on a battery pack mounting portion (not shown) of the electric device main body 201 (see FIG. 10 described later). The rail grooves 7a and 7b are formed so as to extend in a direction parallel to the mounting direction of the battery pack 1 and to project to the left and right sides of the upper case 2. The rail grooves 7a and 7b are formed in a shape corresponding to a rail (not shown) formed on the electric device main body side, and the latch 19a is in a state where the rail grooves 7a and 7b are fitted with the rail on the electric device main body side. , The battery pack 1 is fixed to the main body of the electric device by locking with the locking portion 19c which is the claw of 19b. When removing the battery pack 1 from the main body of the electric device, by pushing the latches 19a and 19b on the left and right sides, the locking portion 19c moves inward and the locked state is released. Therefore, the battery pack 1 is released in that state. Is moved to the opposite side of the mounting direction.

The lower surface 3 and the upper surface 5 of the upper case 2 are formed so as to have different heights in a stepped manner, and a plurality of slot portions extending rearward from the connecting portions thereof are formed. The slot portion is a portion cut out so as to have a predetermined length in the battery pack mounting direction, and has eight slots 11 to 18. Inside the notched portion of the slot, a plurality of connection terminals (connection terminal group) that can be fitted with the device side terminal of the electric device main body or an external charging device (not shown) are arranged. In slots 11 to 18, the slot 11 on the right side of the battery pack 1 near the rail groove 7a serves as the insertion port for the positive electrode terminal (C + terminal) for charging, and the slot 12 serves as the insertion port for the positive electrode terminal (+ terminal) for discharging. Become. Further, the slot 17 on the left side close to the rail groove 7b serves as an insertion port for the negative electrode terminal (-terminal). Between the positive electrode terminal and the negative electrode terminal, a plurality of signal terminals for transmitting signals to the battery pack 1 and the main body of the electric device or an external charging device (not shown) are arranged, and here, four slots for signal terminals are arranged. 13 to 16 are provided between the power terminal groups. The slot 13 is a spare terminal insertion port, and no terminal is provided in this embodiment. The slot 14 is an insertion port for a T terminal for outputting a signal that serves as identification information of the battery pack 1 to the main body of the electric device or the charging device. The slot 15 is an insertion port for a V terminal for inputting a control signal from an external charging device (not shown). The slot 16 is an insertion port for an LS terminal for outputting battery temperature information by a thermistor (temperature sensitive element) (not shown) provided in contact with the cell. On the left side of the slot 17, which is the insertion port of the negative electrode terminal (-terminal), is for the LD terminal (for the abnormal signal terminal) that outputs the abnormal stop signal by the battery protection circuit (not shown) included in the battery pack 1. Slot 18 is provided.

On the rear side of the upper surface 5, a raised portion 6 formed so as to be raised is formed. The vicinity of the center of the raised portion 6 is formed in a recessed shape, and a wind window 9a composed of a plurality of slits is formed on the lower center surface of the recessed portion. A wind window 9b is formed on the front side wall of the lower case 8 so as to correspond to the wind window 9a. When the battery pack 1 is mounted at a predetermined position (battery pack mounting portion) of the electric device main body 201 (see FIG. 10), a plurality of terminals (device side terminals) arranged on the electric device main body 201 and the battery pack 1 A plurality of connection terminals arranged in the above are in contact with each other to be in a conductive state.

2A and 2B are wiring diagrams of the battery cells of the battery pack 1 of the present embodiment and the conventional example, FIG. 2A is a wiring diagram of the battery pack 1 of the present embodiment, and FIG. It is a wiring diagram of a battery pack. As shown in FIG. 2B, conventionally, in order to realize a battery pack having a rated DC voltage of 36 V, 10 battery cells 131 to 135 and 141 to 145 having a rated output of 3.6 V per battery are connected in series. Was. An example of the battery cell used is the so-called "18650 size", which has a columnar shape with a diameter of 18 mm and a length of 65 mm. On the other hand, in this embodiment shown in FIG. 2 (A), the size is smaller than the "18650 size", that is, the length is short called "18350 size" which is a columnar shape having a diameter of 18 mm and a length of 35 mm. The battery cells were used, and 12 battery cells were used instead of the conventional 10 battery cells. That is, the battery pack 1 having a rated DC voltage of 36 V was realized by connecting the battery cells 31 to 36 and 41 to 46 in series. Here, the nominal voltage of the battery cell is 3.6 V, which corresponds to the first voltage, and the total voltage of the nominal voltage is 3.6 V × 12 = 43.2 V. On the other hand, the rated voltage of the electric tool main body 201, which will be described later, is 36V, and the voltage (43.2V) of the battery pack 1 is larger than the rated voltage (36V) of the electric tool main body 201. The nominal voltage of the conventional battery pack (FIG. 7 (A) described later) is 36 V.

FIG. 3 is a diagram showing the discharge characteristics of a battery pack using 10 and 12 battery cells. The horizontal axis is the discharge capacity (unit: Ah), and when the discharge voltage is constant (for example, 1C), the horizontal axis corresponds to the passage of time. The vertical axis is the battery voltage (unit: V). The discharge characteristic 81 is a curve showing the discharge characteristic in a state where 10 “18650 size” battery cells shown in FIG. 2B are connected in series. The "18650 size" battery cell has a voltage of about 42V in a fully charged state as shown by the arrow 81a, and the voltage gradually decreases as the discharge progresses using an electric tool, and the rated voltage is 36V near the arrow 81b. After that, it gradually decreases.

The discharge curve 83 is shown for comparison, and is a diagram showing discharge characteristics in a state where 10 so-called “18350 size” battery cells are connected in series. In this case, it has a voltage of about 42V in a fully charged state as shown by arrow 83a, and when discharging proceeds using an electric tool, the voltage drops significantly as shown by arrow 83b and falls below the rated voltage of 36V of the electric tool body. It ends up. This is because the battery capacity of the "18350 size" battery cell is about half that of the "18650 size" battery cell, so that the voltage drop phenomenon is remarkable. As described above, the inventors have found that when a "18350 size" battery cell is used, the discharge capacity falls below the rated voltage of 36 V before reaching 0.1 Ah, which is not practical. .. Therefore, in the battery pack 1 of this embodiment, 12 "18350 size" battery cells are connected in series to realize a rated voltage of 36V.

The discharge characteristic of the battery pack 1 of this embodiment is as shown in 82. The initial voltage at the time of full charge becomes about 50V as shown by the arrow 82a. Then, as shown by the arrow 82b, the initial voltage (about 42V) for 10 battery cells is reached only when the discharge capacity is close to 0.1Ah. Subsequent voltage drop conditions show characteristics similar to the discharge characteristics 81 of 10 "18650 size" battery cells until the discharge capacity reaches around 0.7 Ah. As shown by the arrow 82c, the battery voltage drops significantly when the discharge capacity is 0.7 Ah or later, because the capacity of the "18350 size" battery cell is smaller than that of the "18650 size" battery cell. be.

As described above, as shown by the discharge characteristic 82 in FIG. 3, even when small battery cells 31 to 36 and 41 to 46 are used, the rated voltage is stably maintained until the discharge capacity reaches around 0.7 Ah. It was found that it can be used at the above (36V or higher). However, if power is supplied to the electric device main body with the high battery voltage reaching the arrows 82a to 82b, there is a risk that the electric device main body side may be damaged. Therefore, in this embodiment, the output voltage in the high voltage section from the arrows 82a to 82b is limited so as to be lowered (stepped down) to a usable specified voltage. FIG. 4 illustrates the control.

FIG. 4 is a diagram for explaining the discharge characteristics of the battery pack of the conventional example and the discharge control of the battery pack 1 according to the present embodiment, and FIG. 4A is a diagram for explaining the discharge control of the battery pack 1 of the present embodiment without limiting the output of the battery pack 1 of the present embodiment. It is a discharge characteristic 82 when it is output as it is. The voltage at full charge of the conventional battery pack using 10 lithium-ion batteries is 42V, which is higher than the rated voltage of 36V on the main body of electric equipment such as electric tools in the section of arrows 82a to 82b of the discharge characteristic 82. The voltage gets too high. Therefore, in this embodiment, the output in the section of arrows 82a to 82b is controlled by switching using a semiconductor switching element, for example, PWM control, so that the effective voltage output from the battery pack 1 is fully charged by the conventional battery pack. It is controlled so that it is almost the same as the current voltage of 42V. PWM (Pulse Width Modulation) control has a constant cycle, and the duty cycle of the pulse width (time ratio of H and L of the pulse width) is set according to the magnitude of the input signal to the control terminal of the semiconductor switching element. By changing it, the effective value of the output voltage is controlled. If the PWM-controlled output is used as the output of the battery pack 1 as it is, there will be a section where the voltage is 0. Therefore, it is advisable to provide a smoothing circuit on the output side of the PWM control circuit (details will be described later in FIG. 5). do).

The output after the output is limited by the PWM control circuit is the discharge characteristic 85. Here, the discharge voltage is output from the output limiting circuit described later in the sections of time 0 to t ₁ , t ₂ to t ₃ , and t ₄ to t ₅ (assumed to be the on section of the semiconductor switching element), and times t ₁ to t. _2. The section from _t3 to t4 is set so that the discharge voltage is not output from the output limiting circuit ₍ the section is set as the off section of the semiconductor switching element). _In this way, in the section from time 0 to t5, the output of the discharge voltage is limited by PWM control, and the output voltage (effective value) from the battery pack 1 is around 42V when the conventional battery pack is fully charged. After time _t5 , the output restriction using the semiconductor switching element was released. As described above, in this embodiment, the total voltage of the 12 battery cells is the reference voltage Vs (= 41V) in the high voltage section close to full charge, or the voltage when the conventional battery pack is fully charged (for example, 42V). When it is higher than, the output voltage from the battery pack 1 is limited so that it is output from the positive and negative terminals, and when it is below the reference voltage Vs, the limit is released and the voltage of the series connection of 12 battery cells. Was configured to be output as it is. As for the PWM control in the output limiting section, the intervals T1 and T2 are shown extremely large for the sake of explanation in FIG. 4B, but the PWM control cycle is actually set sufficiently small.

FIG. 5 is a block diagram showing an internal circuit of the battery pack 1 of FIG. Here, only the basic circuit blocks such as the battery cell group, the protection IC 51, the microcomputer 50, the PWM control circuit (output limiting unit) 60, and the smoothing circuit 70 according to this embodiment are shown, and other related circuits, In particular, the illustration of a circuit that communicates with an external electric device main body and a signal terminal with an external charger is omitted. The battery pack 1 is configured to have a positive electrode terminal 22 and a negative electrode terminal 27 arranged in the internal space of the slots 12 and 17 of FIG. In addition to these connection terminals, the battery pack 1 is provided with a positive electrode terminal (C +) for charging and other signal terminal groups (T terminal, V terminal, LS terminal, LD terminal), which are shown here. Is omitted. A series-connected positive electrode of a battery cell group (31 to 36, 41 to 46) is connected to the positive electrode terminal 22. Further, the negative electrodes of the battery cells (31 to 36, 41 to 46) connected in series are connected to the negative electrode terminal 27.

The terminals on both sides of the battery cells 31 to 36 and 41 to 46 are connected to the protection IC 51 for monitoring the voltage. The protection IC 51 executes a cell balance function, a cascade connection function, and a disconnection detection function in addition to an overcharge protection function and an overdischarge protection function by inputting voltages across the battery cells 31 to 36 and 41 to 46. This is an integrated circuit commercially available as a "protection IC for lithium-ion batteries". The protection IC 51 is connected to the microcomputer 50. When the voltage of any battery cell drops below a predetermined value and becomes over-discharged, the protection IC 51 outputs a signal (high signal) indicating over-discharge to the microcomputer 50, and the protection IC 51 outputs one of the batteries at the time of charging. When the cell voltage reaches a predetermined value or more and becomes an overcharged state, a signal (high signal) indicating overcharge is output to the microcomputer 50.

The power supply circuit 52 generates a reference voltage of 3.3 V by using the voltages across the battery cells 31 to 36 and 41 to 46 (battery cell group), and the reference voltage (whether) is used as a driving power source for the microcomputer. It is supplied to 50. The voltage detection circuit (voltage detection unit) 53 is a circuit for lowering the positive voltage of the battery cell 31 (battery cell group) to input to the microcomputer 50, and the microcomputer 50 is a battery from the output voltage 54 of the voltage detection circuit 53. The voltage (total voltage of series connection of battery cells 31 to 36 and 41 to 46) can be measured. A shunt resistor 49 is interposed in the path of the battery cell 46 (battery cell group) on the negative electrode terminal 27 side. The current detection circuit 55 outputs an output voltage 56 proportional to the voltage across the shunt resistor 49 to the microcomputer 50, so that the microcomputer 50 outputs the current flowing through the battery cells 31 to 36 and 41 to 46 (discharge current or charge of the battery pack 1). Current) can be measured.

The microcomputer 50 integrates and controls the state and operating state of the battery cell by monitoring the voltage value, the current value, and the cell temperature. Further, when an urgent stop of the electric device main body (not shown) is required, a discharge prohibition signal is transmitted to the electric device main body side via the LD terminal. Further, when the battery pack 1 is attached to an external charging device (not shown) and charging is performed, when the protection IC 51 detects that the voltage of the battery cell exceeds a predetermined upper limit value, it is overcharged. An overcharge signal indicating the state is sent to a charging device (not shown) via an LS terminal (not shown).

The microcomputer 50 can switch between holding and releasing the power supply voltage (whether) applied to itself, and can switch between a normal operation state (normal mode), an operation function limited state (so-called sleep mode), and an operation stop state (so-called shutdown mode). Have. The normal mode is a state in which the microcomputer 50 is always activated. The sleep mode is a mode in which the operation of the external circuit and the function of the microcomputer 50 itself is limited to the minimum, and the microcomputer 50 starts up intermittently by itself, for example, an operation such as stopping for 240 milliseconds after starting for 10 milliseconds. repeat. As a result, the power consumption of the battery cell can be suppressed. The shutdown mode is a state in which the reference voltage VDD is not supplied at all, and the microcomputer 50 is completely stopped. The microcomputer 50 can operate not only when the battery pack 1 is attached to the main body of the electric device but also when it is not attached. However, when the battery pack 1 is not attached to the main body of the electric device, or when the main body of the electric device has not been used for a certain period of time even when the battery pack 1 is attached, for example, the trigger operation (switch operation) of the main body of the electric device is completed. If the trigger operation is not performed for about 2 hours after that, the microcomputer 50 goes into the sleep state. When the switch of the electric device main body is operated again and a current flows through a load unit such as a motor, the microcomputer 50 detects an increase in the current value detected by the current detection circuit 55 and returns to the normal mode. Since the power supply circuit 52 of the microcomputer 50 is shared with the protection IC 51, when the microcomputer is started, the protection IC 51 is also started at the same time.

A PWM control circuit 60 and a smoothing circuit 70 are interposed between the battery cell group (31 to 36, 41 to 46) and the positive electrode terminal 22 and the negative electrode terminal 27. The PWM control circuit 60 uses a semiconductor switching element 61 to perform high-speed switching, for example, PWM control of the output (output voltage) of the battery cell group. The output power (output voltage) is controlled by repeating on (conducting state) and off (non-conducting state) of the semiconductor switching element 61. As the semiconductor switching element 61, for example, a MOSFET (metal oxide semiconductor field effect transistor) can be used, and on or off can be switched by inputting the control signal A62 transmitted from the microcomputer 50 to the gate. The microcomputer 50 changes the on-time width by changing the on / off cycle of the pulse train. By switching at an early cycle, an arbitrary voltage proportional to the on pulse width can be obtained.

The smoothing circuit 70 is a capacitor 71 connected between the output line to the positive electrode terminal 22 and the output line to the negative electrode terminal 27. As the capacitor 71, for example, an electrolytic capacitor can be used, and it is a circuit for smoothing (smoothing) the intermittent output switched by the PWM control circuit 60 to a state closer to direct current. Further, since the waveform of the output voltage adjusted by the PWM control circuit 60 is superposed with noise, it is smoothed by the smoothing circuit 70 and output to the positive electrode terminal 22 and the negative electrode terminal 27.

FIG. 6 is a diagram showing discharge control of the battery pack 1 according to the present embodiment. The microcomputer 50 limits the output voltage from the battery pack 1 by performing PWM control only during the output limiting section L. As a result, as shown in FIG. 6, the effective voltage becomes about 41V (or 42V) in the output limiting section L, so that the battery pack 1 having the same discharge characteristics as the conventional battery pack using 10 18650 cells is realized. did it. Further, by configuring the small battery cells to be used in a larger number than the number required to achieve the rated voltage, there is an effect that the battery pack can be miniaturized. When compared in terms of battery cell size, the 18350 size battery cell has a volume ratio of 54% and a weight ratio of 47% as compared with the 18650 size battery cell. As a result, the cell volume ratio can be 65% and the cell weight ratio can be 56% even with 12 18350 size battery cells as compared with 10 18650 size battery cells. Further, by using a small battery cell, the degree of freedom in the arrangement method inside the housing of the battery pack 1 is increased.

7A and 7B are views showing an example of battery cell arrangement in a battery pack, FIG. 7A is a conventional battery pack, and FIG. 7B is a battery pack of this embodiment. FIG. 7A shows a conventional battery pack having a rated voltage of 36 V, in which 18650 size battery cells 131 to 135 and 141 to 145 are connected in series. The battery cells 131 to 135 and 141 to 145 are arranged so that the central axis in the longitudinal direction extends in a direction orthogonal to the mounting direction (front-back direction), that is, in the left-right direction. Since FIG. 7 is a diagram for explaining the stacking direction of the battery cells, a separator made of synthetic resin for stably fixing the battery cells 131 to 135 and 141 to 145 and electricity between the battery cells are provided. The illustration of the connection tab etc. to be connected is omitted. The circuit board 130 is arranged above the separator (not shown) that holds the battery cell.

It can be understood from FIG. 7A that the circuit board 130 is arranged horizontally on the upper side of the battery cells 131 to 135 stacked on the upper side. On the front side of the circuit board 130, a connection terminal group 21 is arranged so as to extend in the left-right direction. The connection terminal group 21 is composed of a plurality of metal terminals, and the metal terminals are fixed to the circuit board 130 by soldering. After manufacturing and assembling, each terminal of the connection terminal group 21 is shown in FIG. It will be located inside the slots 11a to 11h. Various electronic elements (not shown here) such as a battery protection IC, a microcomputer, a PTC thermistor, a resistor, and a capacitor (not shown here) are mounted on the circuit board 130. As the material of the circuit board 130, a printed circuit board in which pattern wiring is printed by a conductor such as a copper foil on a substrate impregnated with a resin having an insulating property can be used.

FIG. 7B is a layout diagram of battery cells 31 to 36 and 41 to 46 in the battery pack 1 having a rated voltage of 36 V in this embodiment. Here, for comparison of size, the circuit board 130 is shown in the same size as that used in FIG. 7 (A). The connection terminal group 21 uses the same parts as the conventional battery pack and the battery pack 1 of this embodiment. The battery cells 31 to 36 and 41 to 46 are of so-called 18350 size, and have the same diameter (18 mm) as the battery cells 131 to 135 and 141 to 145 shown in FIG. 7 (A), but have a length of 65 mm. It is as short as 35 mm. Therefore, it is possible to arrange the battery cells 31 to 36 and 41 to 46 so that the central axis direction in the longitudinal direction is in the front-rear direction. At this time, it is important to maintain the insulating property between the battery cells 31 to 36 stacked on the front side and the battery cells 41 to 46 stacked on the rear side by means such as interposing an insulating sheet. In this embodiment, a partition plate 20 (described later in FIG. 9) for partitioning in the front-rear direction is provided inside the lower case 8, and the partition plate 20 is interposed in the gap between the front battery cell group and the rear battery cell group. Then, good insulation can be achieved. As in FIG. 7A, the illustration of two sets of separators for stably fixing the battery cells 31 to 36 and 41 to 46, a connection tab for electrically connecting the battery cells, and the like are omitted. is doing.

As can be understood in comparison with FIG. 7A, in the battery pack of this embodiment, the battery pack 1 having a rated voltage of 36 V can be realized in a space sufficiently smaller than that of the circuit board 130. Moreover, since 12 cells are used instead of the 10 cells normally required for battery cells, it is possible to suppress the voltage drop caused by using a small battery cell and maintain the required voltage until near the end of discharge. became. In the case of the arrangement shown in FIG. 7B, the miniaturization of the battery pack 1 can be promoted by redesigning the circuit board 130 to improve the degree of integration.

By using the small battery cells 31 to 36 and 41 to 46, the degree of freedom in arranging the battery cells in the battery pack 1 is increased. 8 (A) and 8 (B) are different arrangement views of the battery cells 31 to 36 and 41 to 46 in the battery pack 1 having the rated voltage of 36 V in this embodiment. FIG. 8A shows an example in which the central axes of the battery cells 31 to 36 and 41 to 46 are arranged vertically (toward the vertical direction) so as to be vertical (orthogonal to the circuit board 130). be. Even in such an arrangement, it is preferable to provide a partition plate 20 (described later in FIG. 9) for partitioning in the front-rear direction inside the lower case 8 and to interpose the partition plate 20 in the gap. Even if it is arranged in this way, it can be configured to be smaller than the conventional battery pack shown in FIG. 7 (A).

In FIG. 8B, the battery cells 31 to 36 are arranged side by side in the front-rear direction on the right half of the battery pack 1 so that their longitudinal directions are left and right, respectively, and the battery cells 41 to 46 are arranged on the left half in the right half. Arranged side by side in the same way as. With such an arrangement, the width becomes wider than the conventional battery pack shown in FIG. 7A when viewed in the left-right direction, but the height of the battery pack 1 does not need to be stacked in the vertical direction. It can be suppressed. In the arrangement shown in FIG. 8B, the shape of the lower case (not shown) of the battery pack is changed to form a vertical wall (partition wall) (not shown) extending in the vertical and front-back directions in the center of the left and right. It is preferable to ensure the insulation between the battery cells 31 to 36 and the battery cells 41 to 46.

FIG. 9 is a perspective view of the lower case 8 of the battery pack 1 of this embodiment. The lower case 8 has a substantially rectangular parallelepiped shape with an open upper surface, and is composed of a bottom surface, a front wall 10a extending vertically with respect to the bottom surface, a rear wall 10b, a right side wall surface 10c, and a left side wall surface 10d. , An opening surface 8a is formed on the upper side. A wind window 9b for sucking outside air or exhausting inside air is formed on the front wall 10a. In the battery pack 1 of this embodiment, 12 so-called 18350 size battery cells are accommodated, and a partition (partition plate) 20 formed substantially in the vicinity of the center in the front-rear direction of the lower case 8 is provided. By providing the partition 20, one cell unit by the battery packs 31 to 36 and one cell unit by the battery cells 41 to 46 can be separated and arranged in the partitioned space. Further, the rigidity of the lower case 8 can be increased by providing the partition 20. Since no air hole is formed in the partition 20 shown in FIG. 9, it may be disadvantageous for cooling in the two cell unit accommodating spaces. In that case, one or a plurality of through holes (not shown) may be formed in the partition 20. As the shape of the through hole, various types such as a slit shape and an elliptical hole can be considered. By forming the plurality of through holes in this way, it is possible to secure the cooling air volume over the two cell unit accommodating spaces.

FIG. 10 is a block diagram showing a connection circuit between the battery pack 1 and the electric device main body 201 of this embodiment. The electric device main body 201 is a kind of a power tool main body that operates at a rated voltage of 36 V, and operates using the battery pack 1 of this embodiment as a power source. The battery pack 1 has the configuration shown in the circuit diagram of FIG. 5, and a partial configuration thereof is schematically shown in FIG. The battery cells 31 to 36 form one cell unit, and the battery cells 41 to 46 form another cell unit, and these cell units are connected in series. Further, these series outputs are connected to the positive electrode terminal 22 and the negative electrode terminal 27 via the PWM control circuit 60 and the smoothing circuit 70 shown in FIG.

The electric device main body 201 is a device (power tool) having a rated voltage of 36 V, and has a load device by a motor 203. As the motor 203, for example, a DC motor or a brushless motor driven by using an inverter circuit can be used, and the output shaft 204 is driven via the power transmission mechanism 210. As the power transmission mechanism 210, a known mechanism such as a combination of a reduction mechanism using planetary gears and a striking mechanism using a hammer and anvil may be used. The rotation of the motor 203 is controlled to be turned on or off by a trigger type switch 206, and the control device 250 controls the rotation of the motor 203. The control device 250 includes an inverter circuit, generates drive power from the electric power input via the positive electrode terminal 222 and the negative electrode terminal 227 via the inverter circuit, and drives the motor 203 via the three power lines.

FIG. 11 is a flowchart showing the output limiting procedure of the battery pack 1 shown in FIG. This flowchart can be executed by software by a program stored in advance in the microcomputer 50 of the control unit included in the battery pack 1. Further, this flowchart starts when the switch 206 is turned on by the operator pulling the trigger lever, and ends when the switch 206 is turned off. The semiconductor switching element 61 is in the off state. First, when the switch 206 is turned on, the semiconductor switching element 61 is turned on, and discharging from the battery pack 1 to the electric device main body 201 is started. The microcomputer 50 measures the output voltage (battery voltage) of the battery pack 1 (battery cell group) at that time, and the voltage is less than 41 V, which is the reference voltage Vs (or the voltage when the conventional battery pack is fully charged, less than 42 V). (Step 91). Here, when the output voltage is not less than 41V, that is, when it is 41V or more, the microcomputer 50 outputs the intermittent control signal A62 to the gate of the semiconductor switching element 61 of the PWM control circuit 60 (see FIG. 5). As a result, the voltage (effective value of the voltage) output from the battery pack 1 to the electric device main body 201 is lowered, and the process returns to step 91 (step 94). This decrease is limited to the discharge characteristic 85 in the output limiting section L described with reference to FIG. 4 (B). The semiconductor switching element 61 is in the off state before being connected to the main body of the electric device (the battery pack 1 is independent), but may be in the on state. That is, it may be turned on while the microcomputer 50 is operating.

When the output voltage (battery voltage) becomes less than 41V in step 91, the microcomputer 50 outputs a continuous high signal as a control signal A62 to the gate of the semiconductor switching element 61 of the PWM control circuit 60 (see FIG. 5). By continuing to output, the duty ratio is set to 100%, and the output from the battery cell is directly output to the positive electrode terminal 22 and the negative electrode terminal 27. Next, the microcomputer 50 determines whether or not even one of the battery cells has a threshold voltage of 2.5 V or less (the total voltage of the battery cells, the battery voltage is 30 V or less), and the voltage 2 of all the battery cells. If it is larger than .5V or the battery voltage is larger than 30V, the process returns to step 91. If the battery cell voltage is 2.5V or the battery voltage is less than 30V, a discharge prohibition signal (LD signal) (not shown) is sent to the electrical equipment main body 201 side. By sending out, the discharge from the battery pack 1 is terminated. During the procedure of steps 91 to 93, the switch 206 is turned off when the operator releases the trigger lever. When the switch 206 is turned off, the load disappears (because there is no load), so the battery voltage is restored, and if it is not in the over-discharged state, "No" is set in step 93 and the process returns to step 91. In step 91, the control is performed according to the battery voltage. That is, regardless of the operating state of the switch 206, when the battery pack 1 is connected to the power tool main body 201, the process of FIG. 11 is executed. Therefore, the rating of the power tool main body 201 even when there is no load (when not working). The optimum voltage can be supplied to the voltage.

As described above, according to the battery pack 1 of the present embodiment, the battery pack 1 is realized by the number of battery cells (n: n> m) which is larger than the number of m of battery cells required for the predetermined rated voltage of the electric device main body. However, by performing output limit control when the remaining capacity is large, it was possible to realize a battery pack that can stably supply the output voltage (battery voltage) to the main body of the electric device having a predetermined rated voltage. In addition, since n (however, n> m) battery cells are used instead of m, even if the remaining battery level drops to less than half, the voltage above the rated voltage can be maintained. It can be operated stably.

Next, the battery pack 1A of the second embodiment of the present invention will be described. FIG. 12 is a block circuit diagram of the battery pack 1A according to the second embodiment of the present invention. The difference from the battery pack 1 of the first embodiment shown in FIG. 5 is that a switch circuit 63 for switching is provided so that the output path using the PWM control circuit 60 and the bypass path not used can be switched. It is in. When the output voltage of the battery pack _1A (battery cell group) is less than the threshold VS, the semiconductor switching element 66 is turned on, the semiconductor switching elements 61 and 64 are turned off, and the output voltage of the battery cell group is used as it is. Is output to the connection terminals (positive electrode terminal 22, negative electrode terminal 27). However, when the semiconductor switching element 61 is used, switching loss may occur, the battery output may be consumed due to heat generation, and the output of the battery pack may be slightly reduced. Therefore, in order to prevent switching loss, a switch circuit is provided so that the output of the battery cell group can be switched between being directly output to the smoothing circuit 70 and being output to the semiconductor switching element 61. These switching controls are performed by the control signals A62, B65, and C67 from the microcomputer 50.

The switch circuit 63 is basically composed of two semiconductor switching elements 64 and 66. The semiconductor switching element 64 can use, for example, a MOSFET, and switches on or off by inputting a control signal B65 transmitted from the microcomputer 50 to the gate. An output path 57 that bypasses the semiconductor switching elements 61 and 64 is connected to the switch circuit 63, and the semiconductor switching element 66 is provided in the middle of the output path 57. The semiconductor switching element 66 can use, for example, a MOSFET, and is switched on or off by inputting a control signal C67 transmitted from the microcomputer 50 to the gate.

By controlling the semiconductor switching elements 61, 64, and 66 in this way, either (1) output is limited after using PWM control, or (2) output is limited using PWM control. It is possible to switch to either output without performing the output, or (3) the microcomputer 50 is shut down and all of the semiconductor switching elements 61, 64, and 66 are turned off. The lower right table of FIG. 12 shows the states of the semiconductor switching elements in these cases (1) to (3). When the output voltage of the battery pack 1A is equal to or higher than the threshold voltage _VS , the semiconductor switching element 64 is turned on and the semiconductor switching element 61 is controlled by PMW as shown in (1), so that the output voltage from the battery pack 1A is effective. Adjust the value below the specified voltage. At this time, the semiconductor switching element 66 is off. In this way, whether or not the output of the battery cell group is PWM controlled by the semiconductor switching element 61 can be switched by turning on / off the semiconductor switching elements 64 and 66. When the output voltage of the battery pack 1A is less than the threshold voltage Vs, as shown in (2), the semiconductor switching elements 61 and 64 are turned off, and the semiconductor switching element 66 is turned on to obtain the voltage of the battery cell group (battery). Voltage) is output. When the microcomputer 50 is in the shutdown mode, the control signals A62, B65, and C67 are not output from the microcomputer 50. Therefore, as shown in (3), the semiconductor switching elements 61, 64, and 66 are turned off, and the battery voltage is the discharge terminal ( It is not output from the positive electrode terminal 22 and the negative electrode terminal 27).

FIG. 13 is a block diagram showing a connection circuit between the battery pack 301 and the electric device main body 201A according to the third embodiment of the present invention. The battery pack 301 of the third embodiment has a first battery cell group (first cell unit) and a second battery cell group (second cell unit), and the respective outputs are independent positive electrode terminals and negative electrodes. Connected to the terminal. The first battery cell group (first cell unit) is composed of battery cells 31 to 36, and the second battery cell group (second cell unit) is composed of battery cells 41 to 46. As the positive electrode terminals, two positive electrode terminals (upper positive electrode terminal 322a and lower positive electrode terminal 322b) are provided in the slot 12 shown in FIG. 1 so as to be separated in the vertical direction. Further, as the negative electrode terminals, two negative electrode terminals (upper negative electrode terminal 327a and lower negative electrode terminal 327b) are provided in the slot 17 shown in FIG. 1 so as to be separated in the vertical direction. That is, the number (n) of the battery cells connected in series in the battery pack 301 is set to 6, and they are housed in the two sets of battery pack 301 as the same circuit configuration as in FIG.

The output of the first battery cell group (battery cells 31 to 36) is connected to the positive electrode terminal 322a and the negative electrode terminal 327b via the first PWM control circuit 361 and the first smoothing circuit 371. Further, the outputs of the second battery cell group (battery cells 41 to 46) are connected to the positive electrode terminal 322b and the negative electrode terminal 327a via the second PWM control circuit 362 and the second smoothing circuit 372. The first PWM control circuit 361 and the second PWM control circuit 362 have the same configuration as the PWM control circuit 60 shown in FIG. 5, and the first smoothing circuit 371 and the second smoothing circuit 372 have the same configuration as the smoothing circuit 70 shown in FIG. It is a composition. Since it is not necessary to provide two control units 390 including a microcomputer, one control unit 390 controls both the first PWM control circuit 361 and the second PWM control circuit 362. Although not shown here, the battery cell protection ICs (see 51 in FIG. 5) are divided into the first battery cell group (battery cells 31 to 36) and the second battery cell group (battery cells 41 to 46). It is good to provide each. The specific configurations of the positive electrode terminals 322a and 322b and the negative electrode terminals 327a and 327b are described in the prior application by the applicant (International Publication 2019/017184), so please refer to them.

The electric device main body 201A is an electric device (electric tool) having a rated voltage of 18V and driving a power transmission mechanism 210A by using a motor 203A as a load device to apply a rotational force to an output shaft 204. Except for the difference between the rated voltage of 36V and 18V, the basic circuit configuration is the same as that of the electric device main body 201 shown in FIG. The electric device main body 201A has a positive electrode terminal 222 and a negative electrode terminal 227. Since the positive electrode terminal 222 and the negative electrode terminal 227 are inserted into the slot for the positive electrode terminal and the slot for the negative electrode terminal of the battery pack 301, respectively, when mounted on the battery pack 301, the positive electrode terminal 222 becomes the positive electrode terminal 322a and the positive electrode terminal 322a. It fits into 322b, and the negative electrode terminal 227 fits into the negative electrode terminals 327a and 327b. That is, by mounting the electric device main body 201A and the battery pack 301, the first battery cell group (battery cells 31 to 36) and the second battery cell group (battery cells 41 to 46) on the battery pack 301 side become electric. The positive terminal 222 and the negative terminal 227 of the device main body 201A are connected in parallel, and the rated voltage (battery voltage) of 18V is output to the positive terminal 222 and the negative terminal 227 of the electric tool main body 201A.

Even when such a rated voltage of 18V is output, the microcomputer included in the control unit 390 uses the first PWM control circuit 361 and the second PWM control circuit 362 to use the first battery cell group (battery cells 31 to 36). The output from the battery cell group and the output of the second battery cell group (battery cells 41 to 46) are suppressed to be equal to or lower than the threshold voltage, and the output voltage (battery voltage) from both battery cell groups is controlled to be the same. When 12 battery cells are connected in series, the battery voltage when fully charged is about 50V (see Fig. 3), so when the number of series connections is 6, the battery voltage when fully charged is about half that, about 25V. become. On the other hand, a conventional battery pack having a rated voltage of 36 V has a rated voltage of about 42 V when fully charged, so a battery pack having a rated voltage of 18 V has a rated voltage of about 21 V, which is half of that. Therefore, when the battery pack 301 is connected to the electric device main body 201A having a rated voltage of 18V, the threshold value of the output voltage is set to 21V so that the output voltage (battery voltage) becomes 21V at the time of full charge as in the conventional case. The first and second PWM control circuits 361 and 362 may be controlled by the control unit 390 so as to limit the output voltage when the output voltage (battery voltage) of the battery cell group exceeds 21V.

FIG. 14 is a block diagram when the battery pack 301 according to the third embodiment of the present invention is connected to the electric device main body 401 having a rated voltage of 36 V. The configuration of the battery pack 301 is the same as that shown in FIG. The difference here is the configuration of the positive electrode terminal (422a, 422b) and the negative electrode terminal (427a, 427b) of the electric device main body 401. Here, the positive electrode terminal (422a, 422b) and the negative electrode terminal (427a, 427b) are separately arranged so as to be divided into upper and lower parts, and the positive electrode terminal 422a fits only with the positive electrode terminal 322a when the battery pack 301 is attached. The positive electrode terminal 422b fits only with the positive electrode terminal 322b, the negative electrode terminal 427a fits only with the negative electrode terminal 327a, and the negative electrode terminal 427b fits only with the negative electrode terminal 327b. Further, the positive electrode terminal 422b and the negative electrode terminal 427b on the electrical equipment main body 401 side are connected by a short circuit 429. The positive electrode terminal 422a is connected to the control device 450 as a positive electrode (positive electrode) of plus 36V, and the negative electrode terminal 427a is connected to the control device 450 as a ground potential (negative electrode). When the battery pack 301 is attached to the electric device main body 401 having such a terminal configuration, the first battery cell group (battery cells 31 to 36) and the second battery cell group (battery cells 41 to) are attached via the short circuit 429. The series connection circuit of 46) will be formed.

Even when the series connection circuit of the first battery cell group (battery cells 31 to 36) and the second battery cell group (battery cells 41 to 46) described above is formed, it is included in the control unit 390. The microcomputer uses the first PWM control circuit 361 and the second PWM control circuit 362 to output from the first battery cell group (battery cells 31 to 36) and output from the second battery cell group (battery cells 41 to 46). Is suppressed to the threshold voltage _VS or less, and the voltage from both battery cell groups is controlled to be the same. In the case of the series connection state, it is not necessary to use the first PWM control circuit 361 and the second PWM control circuit 362, and control can be performed by operating only one of the PWM control circuits. In this case, if the switch circuit shown in FIG. 12 is used in combination, efficient control becomes possible.

Although the present invention has been described above based on the examples, the present invention is not limited to the above-mentioned examples, and various modifications can be made without departing from the spirit of the present invention. Although the power tool body has been described as the body of the electric device, it can also be applied to the body of peripheral devices such as radios, fans, and lights. Further, although the electric device main body having a rated voltage of 36 V, the rated voltage of 36 V, or the voltage switching type battery pack has been described, the voltage is not limited to that voltage. For example, it can be applied to a battery pack fixed at a rated voltage of 18 V. The conventional battery pack with a rated voltage of 18V has five 18650 cells connected in series, but if six 18350 cells are connected in series, it is smaller and lighter than the previous battery pack with a rated voltage of 18V, making it easier for workers to handle. Get better. Further, although the battery pack capable of switching the connection method of the battery cell group has been described, it is possible to have three or more sets of battery cell groups. Further, although the battery cell has been described as 18350 size, 18500 size may be used, and the size is not limited.

1 Battery pack 2 Upper case 3 Lower surface 5 Upper surface 6 Raised part 7a, 7b Rail groove 8 Lower case 8a Opening surface 9a, 9b Wind window 10a Front wall 10b Rear wall 10c Right side wall 10d Left side wall 11-18 Slot 19a, 19b Latch 19c Locking part 20 Partition plate 21 Connection terminal group 22 Positive electrode terminal 27 Negative electrode terminal 31-36 Battery cell 41-46 Battery cell 49 Shunt resistance 50 Microcomputer 51 Protection IC 52 Power supply circuit 53 Voltage detection circuit 54 Output voltage 55 Current detection circuit 56 Output voltage 57 Output path 60 Control circuit 61, 64, 66 Semiconductor switching element 62, 65, 67 Control signal 70 Smoothing circuit 71 Condenser 81, 82 Discharge characteristic 83 Discharge curve 85 Discharge characteristic 130 Circuit board 131 to 135 Battery cell 141 to 145 Battery cell 150 Circuit board 201, 201A Electrical equipment body 203, 203A Motor 204 Output shaft 206 Switch 210, 210A Power transmission mechanism 222 Positive electrode terminal 227 Negative electrode terminal 250 Control device 301 Battery pack 322a (upper side) Positive electrode terminal 322b (lower side) Positive electrode Terminal 327a (Upper) Negative terminal 327b (Lower) Negative terminal 361 1st PWM control circuit 362 2nd PWM control circuit 390 Control unit 401 Electrical equipment main unit 422a, 422b Positive terminal 427a, 427b Negative terminal 429 Short circuit 450 Control device Vs Reference voltage

Claims (15)

A battery pack that can be connected to the main body of electrical equipment with the first rated voltage.
A plurality of battery cells in which n battery cells having a nominal voltage of the first voltage are connected in series, and
A terminal portion having a positive electrode terminal and a negative electrode terminal electrically connected to the plurality of battery cells,
A control unit that controls the discharge of the plurality of battery cells,
An output limiting unit provided in the output path between the plurality of battery cells and the positive electrode terminal or the negative electrode terminal and configured to be able to limit the output voltage from the terminal unit is provided.
The sum of the nominal voltages of the plurality of battery cells is configured to be higher than the first rated voltage.
The battery pack is characterized in that the output limiting unit is configured to limit the output voltage and supply it to the electric device main body when it is connected to the electric device main body in a fully charged state. The battery pack according to claim 1.
The battery pack is characterized in that the output limiting unit is configured to release the limitation and supply the output voltage to the electric device main body when the output voltage drops. The battery pack according to claim 2.
When the battery pack is connected to the main body of the electric device,
If the total voltage of the plurality of battery cells is higher than the reference voltage or the remaining amount of the plurality of battery cells is larger than the predetermined threshold remaining amount, the output voltage is limited.
A battery pack characterized in that the limitation is released when the total voltage is equal to or less than the reference voltage or when the remaining amount is equal to or less than the threshold remaining amount. The battery pack according to claim 3.
The battery cells are connected in series with n batteries.
The battery pack is characterized in that the reference voltage is larger than the voltage when n-1 batteries are connected in series. The battery pack according to any one of claims 1 to 4.
A voltage detection unit that measures the voltage of the battery pack or the battery cell,
The battery pack is characterized in that the control unit limits the output voltage by operating the output limiting unit according to the measurement result of the voltage detecting unit. The battery pack according to claim 5.
The output limiting circuit includes a semiconductor switching element.
A battery pack characterized in that the control unit limits the effective value of the output voltage by PWM controlling the semiconductor switching element. The battery pack according to claim 6.
A battery pack characterized in that a smoothing circuit is provided between the positive electrode terminal and the negative electrode terminal and the output limiting circuit. The battery pack according to claim 6 or 7.
The output limiting circuit has a switch and has a switch.
The switch is characterized in that it switches between a path connected to the semiconductor switching element from the positive electrode of the battery cell connected in series and a path connected to the positive electrode terminal by bypassing the semiconductor switching element. Battery pack. The battery pack according to any one of claims 1 to 8.
The positive electrode terminal has a first positive electrode terminal and a second positive electrode terminal.
The negative electrode terminal has a first negative electrode terminal and a second negative electrode terminal.
The battery cells are connected in series in n to form a first cell unit, which is connected to the first positive electrode terminal and the first negative electrode terminal.
The battery cells are connected in series in n to form a second cell unit, which is connected to the second positive electrode terminal and the second negative electrode terminal.
The first output limiting circuit is provided corresponding to the first cell unit.
A battery pack characterized in that the second output limiting circuit is provided corresponding to the second cell unit. The battery pack according to any one of claims 1 to 9.
The housing of the battery pack is mounted so as to be connected to a lower case accommodating a battery cell, a slot portion accommodating a connection terminal including the positive electrode terminal and the negative electrode terminal, and the electric device main body or an external charging device. Consists of an upper case with a formed portion, and
The lower case is a battery pack characterized by having a partition for accommodating a plurality of the battery cells in a plurality of areas. The battery pack according to claim 10.
A circuit board connected to the connection terminal is provided.
The battery pack is characterized in that the partition is located between the inner bottom surface of the lower case and the bottom surface of the circuit board in the vertical direction. With the electrical equipment body
The battery pack according to any one of claims 1 to 10, wherein the first battery pack has a voltage larger than the first rated voltage when fully charged.
An electric device system including a second battery pack corresponding to the first rated voltage and having a voltage smaller than the voltage of the first battery pack when fully charged. The electrical equipment system according to claim 12.
The first battery pack has a cell unit in which a plurality of first battery cells having a first length are connected in series.
The second battery pack has a cell unit in which a plurality of second battery cells having a second length longer than the first length are connected in series.
An electrical equipment system characterized in that the number of accommodations of the first battery cell is larger than the number of accommodations of the second battery cell. The electrical equipment system according to claim 12 or 13.
An electric device system characterized in that the limited output voltage corresponds to the rated voltage of the second battery pack or the rated voltage of the electric device main body. The main body of the electric device
The battery pack according to any one of claims 1 to 10, which has a voltage larger than the first rated voltage when fully charged, and a plurality of first battery cells having a first length are connected in series. The first battery pack having the connected cell unit is removable and can be attached and detached.
A second battery pack corresponding to the first rated voltage and having a voltage smaller than the voltage of the first battery pack when fully charged, and having a second length longer than the first length. A second battery pack having a cell unit in which a plurality of second battery cells connected in series, which is smaller than the first battery cell, can be attached and detached.

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