power supply

Abstract

To provide a power supply, though being configured to electrically connect a plurality of storage battery packs in series, allowing the number of storage battery packs to be changed appropriately.SOLUTION: A power supply includes: a plurality of connection portions 50 to which storage battery packs 40 are connected, respectively; an internal circuit 100 that electrically connects, one another in series, the respective battery packs 40 which are each connected to the connection portion 50; and an AC output unit 30 that outputs power from the storage battery pack 40. For each connection portion 50, the internal circuit 100 has: a terminal 51 to which one electrode 401 of the storage battery pack 40 is connected; a terminal 52 to which the other electrode 402 of the storage battery pack 40 is connected; and a connection path 110 that electrically connects between the terminal 51 and the terminal 52 when the storage battery pack 40 is not connected to the connection portion 50.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a power supply device. [Background technology]

[0002] Demand for portable power supply devices is increasing to enable electrical devices to be used in locations where commercial power is not directly available, such as outdoors. Such power supply devices typically include a built-in storage battery that outputs power. However, in such a configuration, when the power stored in the storage battery runs out, the power supply device must be connected to a commercial power source and the storage battery must be charged over time.

[0003] The following Patent Document 1 describes a power supply device configured to have a detachable battery pack for a power tool. In this configuration, when the power stored in the battery pack runs out, the battery pack can be replaced with a charged battery pack, allowing the power supply device to continue supplying power.

[0004] Furthermore, Patent Document 2 listed below describes a power supply device configured to have multiple detachable battery packs. By simultaneously outputting power from the multiple battery packs, it is possible to output a large amount of power to a load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-46481 [Patent Document 2] Patent No. 5616104 Summary of the Invention [Problem to be solved by the invention]

[0006] The power supply device described in Patent Document 2 is configured with a battery connection circuit made up of multiple switching elements and diodes to enable switching between the connection modes of multiple battery packs. In such a configuration, the power supply device becomes more complex and larger in size, and it is also necessary to control the battery connection circuit according to the situation.

[0007] Therefore, the inventors have been studying how to electrically connect a plurality of battery packs in series and enable a power supply device to output a large amount of power with a relatively simple configuration.

[0008] However, in such a configuration, if one of the battery packs is removed, the circuit at that point is disconnected, preventing the power supply device from outputting power. For this reason, it is necessary to keep battery packs connected to all of the battery pack connectors provided on the power supply device at all times during use.

[0009] However, in terms of ease of use of the power supply device, it is preferable that the number of battery packs connected to the power supply device be selectable by the user as appropriate depending on the amount of power to be output, etc.

[0010] An object of the present invention is to provide a power supply device that has a configuration in which a plurality of battery packs are electrically connected in series, but in which the number of battery packs can be changed as needed. [Means for solving the problem]

[0011] A power supply device according to one embodiment of the present invention includes a plurality of connection sections to which battery packs are connected, an internal circuit that electrically connects the battery packs connected to the connection sections in series, and an output section that outputs power from the battery packs. For each connection section, the internal circuit has a first terminal to which one electrode of the battery pack is connected, a second terminal to which the other electrode of the battery pack is connected, and a connection path that electrically connects the first terminal and the second terminal when the battery pack is not connected to the connection section.

[0012] In a power supply device configured as described above, multiple battery packs are electrically connected in series by an internal circuit, allowing the device to output a power amount corresponding to the number of battery packs. When no battery packs are attached to some of the connection sections, the first terminal and the second terminal at those connection sections are electrically connected by a connection path. This allows the paths for outputting power from the battery packs connected to the other connection sections to be maintained without being disconnected. Furthermore, the electrical connection between the first terminal and the second terminal is maintained when no battery pack is connected to the connection sections. Therefore, when a battery pack is connected to the connection sections, a short circuit does not occur between the first terminal and the second terminal.

[0013] The power supply device having the above configuration can supply power to a load even when no battery packs are attached to some of the multiple connection sections. This allows the user to change the number of battery packs connected as needed. The power supply device described above may be a general-purpose power supply device that is used by connecting an external load to the output section, or it may be a power supply device configured as an integrated device with the load. In other words, the power supply device may be configured as part of an electrical device such as a portable power tool. [Effects of the Invention]

[0014] According to the present invention, a power supply device is provided that has a configuration in which a plurality of battery packs are electrically connected in series, but in which the number of battery packs can be changed as needed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view of the power supply device according to the first embodiment. [Figure 2] FIG. 2 is a side view of the power supply device according to the first embodiment. [Figure 3] FIG. 3 is a perspective view of the power supply device according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing the power supply device according to the first embodiment with the lower housing removed. [Figure 5] FIG. 5 is a diagram showing the lower housing and the battery pack housed therein in the power supply device according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing the power supply device according to the first embodiment with the upper housing removed. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a circuit diagram that schematically shows the internal configuration of the power supply device according to the first embodiment. [Figure 9] FIG. 9 is a circuit diagram showing a partial configuration of a power supply device according to a modified example. [Figure 10] FIG. 10 is a circuit diagram showing a partial configuration of the power supply device according to the first embodiment. [Figure 11] FIG. 11 is a circuit diagram showing a partial configuration of a power supply device according to a comparative example. [Figure 12] FIG. 12 is a flowchart showing the flow of processing executed by the power supply device according to the first embodiment. [Figure 13] FIG. 13 is a circuit diagram schematically showing the internal configuration of the power supply device according to the second embodiment. [Figure 14] FIG. 14 is a flowchart showing the flow of processing executed by the power supply device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0017] A first embodiment will be described. A power supply device 10 according to this embodiment is a portable power supply device that can be used outdoors and is capable of supplying power to devices such as power tools. A plurality of storage battery packs 40 are connected to the power supply device 10 as a power source. As the storage battery packs 40, for example, those commercially available for use in power tools can be used.

[0018] The configuration of the power supply device 10 will be described with primary reference to Figures 1 to 5. Figure 1 is a front view of the power supply device 10, Figure 2 is a side view of the power supply device 10, and Figure 3 is a perspective view of the power supply device 10. Figure 4 is a view showing the power supply device 10 with a lower housing 23, which will be described later, removed. Figure 5 is a view showing the lower housing 23 and the storage battery pack 40 housed therein. As shown in these figures, the power supply device 10 includes an upper housing 21, a middle housing 22, and a lower housing 23, and has an overall shape that is roughly a rectangular parallelepiped.

[0019] The upper housing 21 is the uppermost part of the power supply device 10. The upper housing 21 is configured as a lid that covers the middle housing 22, which will be described below, from above. A grip portion 201 is formed on the top surface of the upper housing 21. The grip portion 201 is a handle that is grasped by the user when carrying the power supply device 10. Under normal circumstances, the upper housing 21 is fixed to the middle housing 22.

[0020] The middle housing 22 is a portion between the upper housing 21 and the lower housing 23, which will be described later. A space is formed inside the middle housing 22, and components such as a circuit board 80 and a fan 90 (see FIG. 6), which will be described later, are housed in this space. As shown in FIG. 1 and other figures, a pair of grips 202 are formed on each of the left and right side surfaces of the middle housing 22. In addition, a pair of grips 203 are formed on each of the front and rear side surfaces of the middle housing 22. Both of these are provided as handles to be gripped by the user when carrying the device, similar to the grip 201 described above.

[0021] As shown in FIG. 1, an AC output unit 30, a notification unit 60, and an operation unit 70 are provided on the front side surface of the middle housing 22.

[0022] The AC output unit 30 is a part that outputs AC power from the power supply device 10 to the outside. The power output from the AC output unit 30 is power stored in the battery pack 40 and is converted into AC power via an inverter circuit 124 (see FIG. 8 ), which will be described later. In this embodiment, the AC output unit 30 is provided as an AC outlet. A power plug of a device such as a power tool is connected to the AC output unit 30. The AC output unit 30 corresponds to one of the "output units" in this embodiment. The AC output unit 30 is provided with an open / close cover 31. When the AC output unit 30 is not in use and no power plug is connected to it, the open / close cover 31 can be closed to cover the AC output unit 30.

[0023] In addition to the AC output unit 30, the power supply device 10 is also provided with a DC output unit 32 (see FIG. 8), but this is not shown in FIG. 1 and other figures. The DC output unit 32 is a unit that outputs DC power from the power supply device 10 to the outside. The power output from the DC output unit 32 is power stored in the storage battery pack 40, and has been voltage-adjusted via a DC-DC converter 125 (see FIG. 8), which will be described later. The DC output unit 32 may be provided as, for example, a USB connector. The DC output unit 32, together with the AC output unit 30, corresponds to one of the "output units" in this embodiment. Note that the output unit may be configured to include only one of the AC output unit 30 and the DC output unit 32.

[0024] The notification unit 60 is a part that displays various information indicating the operating status of the power supply device 10 and notifies the user of that information. In this embodiment, the notification unit 60 is configured as a liquid crystal display panel. Instead of this mode, the notification of various information by the notification unit 60 may be performed by voice, for example. The types of information notified by the notification unit 60 will be described later.

[0025] The operation unit 70 is a part that is operated by a user of the power supply device 10. The operation unit 70 includes a plurality of switches. These switches include a voltage selector switch 71 and a frequency selector switch 72.

[0026] The voltage changeover switch 71 is a switch for changing the effective value of the AC power output from the AC output unit 30, for example, between 100 V and 200 V. The frequency changeover switch 72 is a switch for changing the frequency of the AC power output from the AC output unit 30, for example, between 50 Hz and 60 Hz.

[0027] A primary switch 73 and a secondary switch 74 are further provided on the front side surface of the middle housing 22. These are both provided in positions separate from the voltage selector switch 71 and the frequency selector switch 72, but are included in the operation unit 70 in this embodiment.

[0028] The primary-side switch 73 is a switch for switching between open and closed states of a section through which power is output from the storage battery pack 40 to each section of the power supply device 10. When the primary-side switch 73 is in an open state, power supply to the boost circuit 123 and the controller 121, which will be described later, is stopped. When the primary-side switch 73 is in a closed state, power is supplied to each section, such as the boost circuit 123 and the controller 121, and the power supply device 10 is in an operable state.

[0029] The secondary-side switch 74 is a switch for switching between open and closed states of the parts through which power is output from the AC output unit 30 and the DC output unit 32. When the secondary-side switch 74 is in an open state, no power is output from the AC output unit 30, etc., even if the inverter circuit 124 or the DC-DC converter 125 is in operation. When the secondary-side switch 74 is in a closed state, AC power is output from the AC output unit 30, and DC power is output from the DC output unit 32.

[0030] The lower housing 23 is the lowest part of the power supply device 10. The lower housing 23 is connected to the middle housing 22 from below. The lower housing 23 is provided with a total of four connection portions 50, which are portions to which the storage battery packs 40 are connected. As shown in FIG. 5 , two of the connection portions 50 are configured to connect the storage battery packs 40 from the front side of the power supply device 10, and the remaining two are configured to connect the storage battery packs 40 from the rear side of the power supply device 10. In this way, in this embodiment, four connection portions 50 are provided, and a maximum of four storage battery packs 40 can be connected.

[0031] 4, a pair of slide guides 230 is provided on each portion of the bottom plate 220 of the middle housing 22 that is above the connection portion 50. Each slide guide 230 has a vertical wall 231 that extends downward from the bottom plate of the middle housing 22, and a horizontal wall 232 that extends from the lower end of the vertical wall 231 toward the storage battery pack 40 (inside). When connected to the connection portion 50, the storage battery pack 40 can slide in the front-to-rear direction (the depth direction of the paper in FIG. 1 ) with its movement in the left-to-right direction restricted by the vertical wall 231 and its movement in the up-to-down direction restricted by the horizontal wall 232.

[0032] As shown in Fig. 4, terminals 51, 52, 53, and 54 that protrude downward are provided in a portion of the bottom plate 220 of the middle housing 22 between the pair of slide guides 230. Furthermore, as shown in Fig. 5, four recesses 410 corresponding to the four terminals 51, 52, 53, and 54 are provided on the top surface of the battery pack 40. Electrodes 401 and the like (not shown in Fig. 5, see Fig. 10) are provided inside each recess 410. When the battery pack 40 is slid toward the rear and connected to the connection portion 50, the terminals 51, 52, 53, and 54 enter the recess 410 of the battery pack 40 and are electrically connected to the electrodes 401 and the like inside the recess 410. The functions of the terminals 51, 52, 53, and 54 and the electrodes 401 will be described later.

[0033] As shown in FIG. 4 , a pair of guide protrusions 251 protruding downward is provided on each of the bottom plate 220 of the middle housing 22, at a portion closer to the battery pack 40 entrance than the pair of slide guides 230. When viewed from the front as in FIG. 1 , the guide protrusions 251 are positioned so as to sandwich the battery pack 40 from both the left and right sides. The distance between the guide protrusions 251 gradually narrows from the front to the back. Therefore, when the battery pack 40 is inserted into the connection portion 50, the battery pack 40 comes into contact with the guide protrusions 251, correcting its left-right position and guiding it to the correct connection position. The "correct connection position" is a position where the terminals 51, 52, 53, and 54 fit into the corresponding recesses 410.

[0034] As shown in FIG. 5 , a recess 204 that is recessed inward is formed in a lower portion of the side wall of the lower housing 23. Furthermore, an inclined surface 261 is formed on the inner surface of the side wall of the lower housing 23 that faces the storage battery pack 40. The inclined surface 261 is formed so that the width of the space that receives the storage battery pack 40 gradually narrows from the front side to the back side, and is connected to the inner surface of the recess 204. When the power supply device 10 is viewed from the front side as shown in FIG. 1 , the recess 204 and the inclined surface 261 are provided on the side wall further to the left of the left storage battery pack 40 and on the side wall further to the right of the right storage battery pack 40, respectively. The same is true when the power supply device 10 is viewed from the rear side.

[0035] When inserting the battery pack 40 into the connection portion 50, the battery pack 40 first hits the inclined surface 261, which roughly corrects its left-right position. Then, the battery pack 40 hits the guide protrusion 251, which guides the battery pack 40 to the correct connection position as described above. In this way, the recess 204 cooperates with the guide protrusion 251 to guide the battery pack 40 to the correct connection position. The user can easily connect the battery pack 40 to the connection portion 50 without having to worry about the positions of the terminals 51 and other components provided on the connection portion 50.

[0036] As shown in Fig. 5, as a result of forming recess 204 in the side wall of lower housing 23, gripping portions 205 are formed above recess 204. When power supply device 10 is viewed from the front side as in Fig. 1, gripping portions 205 are formed on both the left and right sides of power supply device 10. A user can lift power supply device 10 by grasping each gripping portion 205 from below.

[0037] In this way, the power supply unit 10 has multiple gripping portions 201, 202, 203, 205 formed in various positions, so the user can select and grip the gripping portion 201, etc. in a position that is easy to hold, depending on the height of the installation location of the power supply unit 10, the user's own posture, etc.

[0038] 5 and other figures, the lower housing 23 has a bottom plate 233, and each battery pack 40 is connected to a connection portion 50 on the upper surface of the bottom plate 233. Therefore, the sliding battery pack 40 does not come into contact with the upper surface of the place where the power supply device 10 is installed. As a result, the power supply device 10 is configured so that the battery pack 40 is connected to a lower portion thereof, but the battery pack 40 can be smoothly attached and detached.

[0039] The internal configuration of the power supply device 10 will be described with reference to Figures 6 and 7. Figure 6 is a perspective view of the power supply device 10 with the upper housing 21 removed, viewed from diagonally above. Figure 7 is a cross-sectional view taken along line VII-VII in Figure 2. As shown in Figure 6 and other figures, the power supply device 10 includes a circuit board 80 and a fan 90, which are housed inside the middle housing 22.

[0040] The board 80 is an electronic board on which the controller 121, boost circuit 123, etc. (see FIG. 8) provided in the power supply device 10 are configured. The board 80 is housed inside a case 81. Four support columns 82 extending upward from the bottom surface of the middle housing 22 are provided around the periphery of the case 81. The case 81 is held by these support columns 82 at a position spaced upward from the bottom surface of the middle housing 22. As a result, as shown in FIG. 7, a space SP1 is formed below the board 80 and the case 81. Furthermore, a space SP2 is formed above the board 80 and the case 81.

[0041] The fan 90 is a blower that cools the board 80 to maintain an appropriate temperature. When the power supply device 10 is viewed from the rear as shown in FIG. 7 , the fan 90 is located to the left of the board 80. The fan 90 cools the board 80 by, for example, blowing air toward the board 80. A plurality of air vents 210 are formed through the side surfaces of the middle housing 22, one side surface along the air flow direction and the other side surface. The air blown out by the fan 90 flows into the middle housing 22 through the air vents 210 on one side surface, passes through spaces SP1 and SP2, and is then discharged to the outside of the middle housing 22 through the air vents 210 on the other side surface. In this manner, in this embodiment, spaces SP1 and SP2 through which air passes are formed above and below the board 80, enabling efficient air cooling of the board 80.

[0042] In order to improve the cooling efficiency of the substrate 80, the case 81 may be made of a metal material and may function as a heat sink. In this case, fins may be provided on a part of the case 81, for example.

[0043] 4, openings 221 that penetrate the bottom plate 220 from top to bottom are formed in the bottom plate 220 of the middle housing 22 above the respective connection portions 50. This allows some of the air sent out by the fan 90 to reach the battery pack 40 through the openings 221, thereby suppressing a temperature rise in the battery pack 40.

[0044] The circuit configuration of the power supply device 10 will be described mainly with reference to Fig. 8. Of the components shown in Fig. 8, the controller 121, regulator 122, boost circuit 123, inverter circuit 124, and DC-DC converter 125 are configured as circuit elements on a substrate 80.

[0045] First, a description will be given of the configuration of the storage battery pack 40. In Fig. 8, the dotted line marked with the symbol "40" schematically represents the storage battery pack 40 connected to the connection part 50. The storage battery pack 40 has a cell 41 and a pair of electrodes 401, 402.

[0046] The cell 41 is a portion that stores power, and is specifically a lithium-ion battery. Although FIG. 8 shows a schematic diagram in which one storage battery pack 40 has one cell 41, in reality, one storage battery pack 40 has multiple cells 41, and the cells 41 are electrically connected in series (see FIG. 10). The shape of the cell 41 is approximately cylindrical. FIG. 7 shows a cross section of some of the cells 41.

[0047] The electrodes 401 and 402 are a pair of terminals for outputting power from the cell 41 to the outside. Of these, the electrode 401 is a positive terminal, and the electrode 402 is a negative terminal. The electrodes 401 and 402 are provided inside a recess 410 (see FIG. 5) provided on the upper surface of the storage battery pack 40. Note that the storage battery pack 40 is provided with two other terminals (an over-discharge terminal 403 and a temperature terminal 404) in addition to the electrodes 401 and 402, but these are not shown in FIG. 8. These terminals will be described later with reference to FIG. 10.

[0048] As described above, the power supply device 10 has four terminals 51, 52, 53, and 54 for each connection portion 50 to which the storage battery pack 40 is connected. In Fig. 8, only two of these terminals, 51 and 52, are shown, and the remaining terminals 53 and 54 are not shown. Terminals 53 and 54 will be described later with reference to Fig. 10.

[0049] Terminals 51 and 52 are terminals for receiving power supply from the storage battery pack 40. Terminal 51 is a terminal to which a positive electrode 401 of the storage battery pack 40 is connected, and corresponds to the "first terminal" in this embodiment. Terminal 52 is a terminal to which a negative electrode 402 of the storage battery pack 40 is connected, and corresponds to the "second terminal" in this embodiment.

[0050] 8, the battery packs 40 are electrically connected in series in the portion surrounded by the dotted line and labeled "100." The circuit in the portion surrounded by the dotted line and labeled "100," i.e., the circuit configured to electrically connect the battery packs 40 connected to the connection unit 50 in series, is also referred to below as the "internal circuit 100."

[0051] In FIG. 8, the portion designated by the reference numeral "101" is the positive end of the internal circuit 100. In addition, in FIG. 8, the portion designated by the reference numeral "102" is the negative end of the internal circuit 100. These can be said to be portions that input power from the storage battery packs 40 connected in series to elements such as the boost circuit 123 that are outside the internal circuit 100. Hereinafter, these portions will be referred to as "power input portions 101, 102."

[0052] In this embodiment, the battery packs 40 connected to the connection unit 50 are connected in series. Therefore, the voltage input from the power input units 101 and 102 to each unit is higher than the voltage input from a single battery pack 40. This makes it possible to extract a large amount of power while suppressing the current from the battery packs 40.

[0053] Furthermore, in a configuration in which the storage battery packs 40 are connected in series, it is not necessary to make the inter-terminal voltages of all the storage battery packs 40 (i.e., the voltage between the electrode 401 and the electrode 402) the same. This allows the power supply device 10 to operate in a state in which different types of storage battery packs 40 are mixed. For example, power can be supplied from the power supply device 10 to the outside in a state in which storage battery packs 40 with an inter-terminal voltage of 18 V are connected to some of the connection sections 50 and storage battery packs 40 with an inter-terminal voltage of 36 V are connected to other of the connection sections 50.

[0054] Incidentally, in a configuration in which the storage battery packs 40 are connected in series, if a storage battery pack 40 is removed from one of the connection sections 50, the circuit is disconnected at that section, and it appears that power cannot be input from the power input sections 101, 102 of the internal circuit 100. To prevent this situation, the power supply device 10 according to this embodiment has connection paths 110 provided in the internal circuit 100 corresponding to each of the connection sections 50 to which the storage battery packs 40 are connected. The connection paths 110 are provided so as to be electrically parallel to the storage battery packs 40 of the connection sections 50, and connect between the terminals 51 and 52. A diode 111 is provided in each connection path 110. The diode 111 is arranged so that its anode faces the terminal 52 and its cathode faces the terminal 51. In other words, the diode 111 is arranged so that the direction from the terminal 52 to the terminal 51 is the forward direction.

[0055] When a storage battery pack 40 is not attached to some of the connection parts 50, the terminal 51 and the terminal 52 of the connection part 50 are electrically connected by the connection path 110. As a result, the paths for outputting power from the storage battery packs 40 connected to the other connection parts 50 are maintained without being disconnected.

[0056] When the battery pack 40 is connected to the connection unit 50, there is a concern that a short circuit may occur between the terminal 51 and the terminal 52 of the battery pack 40 via the connection path 110, causing a current to flow from the terminal 51 to the terminal 52 via the connection path 110. However, such a current is blocked by the diode 111, and therefore a short circuit does not occur between the terminal 51 and the terminal 52. In this way, the diode 111 functions to block the current in the connection path 110 when the battery pack 40 is connected to the connection unit 50, and corresponds to the "blocking unit" in this embodiment.

[0057] The interrupter may be a circuit element other than the diode 111. FIG. 9 shows a modified configuration in which a switch 112 is used as the interrupter instead of the diode 111. When the battery pack 40 is connected to the connection unit 50, the switch 112 is open at the connection unit 50 as shown in FIG. 9(A). On the other hand, when the battery pack 40 is not connected to the connection unit 50, the switch 112 is closed at the connection unit 50 as shown in FIG. 9(B). To control the interrupter in this manner, for example, a controller 121 (described later) may detect the connection state of the battery pack 40 based on the voltage or the like and switch the switch 112 between open and closed states depending on the connection state. The switch 112 may be, for example, a switching element such as a MOFSET or a contact-type mechanical relay. The interrupter may also include other circuit elements in addition to the diode 111 and the switch 112.

[0058] With the above configuration, the power supply device 10 is configured to be connectable to a plurality of storage battery packs 40, but does not need to have a storage battery pack 40 connected to all of the connection parts 50. For example, if only a relatively small amount of power needs to be output from the power supply device 10, the power supply device 10 can be used with a number of storage battery packs 40 connected that is fewer than the total number of connection parts 50. In this case, the total weight of the power supply device 10 is reduced, making the power supply device 10 easier to carry. In this way, the power supply device 10 is configured to have a plurality of storage battery packs 40 electrically connected in series, but the number of connected storage battery packs 40 can be changed as needed.

[0059] Therefore, the number of battery packs 40 connected to the power supply device 10 can be changed as appropriate depending on the application. For example, when supplying power to a device that consumes relatively large amounts of power, such as a large power tool, four battery packs 40 can be connected, whereas when supplying power to a device that consumes relatively little power, such as a smartphone, only one battery pack 40 can be connected, thereby reducing the overall weight of the power supply device 10.

[0060] Furthermore, if the remaining battery charge in one of the multiple battery packs 40 connected to the power supply device 10 becomes zero, it is possible to remove only that battery pack 40 from the power supply device 10 and continue using the power supply device 10 using the output from the remaining battery packs 40.

[0061] Furthermore, the power supply device 10 can operate without problems even when multiple storage battery packs 40 with different specifications or remaining capacity are connected. For example, multiple storage battery packs 40 with different battery capacities can be connected simultaneously, allowing the user to combine and effectively utilize existing storage battery packs 40. Also, since a fully charged storage battery pack 40 and a partially used storage battery pack 40 can be connected simultaneously, it becomes possible to reuse storage battery packs 40 that have been used for tools, for example, as needed, which has the advantage of eliminating the need to carry more storage battery packs 40 than necessary.

[0062] 8, the description of the circuit configuration of the power supply device 10 will continue. In addition to the internal circuit 100 described above, the power supply device 10 includes a controller 121, a regulator 122, a boost circuit 123, an inverter circuit 124, and a DC-DC converter 125.

[0063] The controller 121 is a microcomputer that controls the overall operation of the power supply device 10. Power for operating the controller 121 is supplied from the battery pack 40 via a regulator 122 to the controller 121. The controller 121 controls the operation of the inverter circuit 124, DC-DC converter 125, etc. based on the states of various switches provided on the operation unit 70. The controller 121 also notifies the user of various pieces of information by sending a signal indicating the operating state of the power supply device 10 to the notification unit 60 and displaying the signal. The controller 121 corresponds to the "control unit" in this embodiment.

[0064] The regulator 122 is a device that generates a constant voltage from the power of the storage battery pack 40 and supplies the voltage to each unit such as the controller 121. In this embodiment, a primary-side switch 73 is disposed between the power input unit 101 and the regulator 122. Therefore, when the primary-side switch 73 is closed by the user, the voltage from the regulator 122 is immediately supplied to the controller 121, and the controller 121 begins to operate. In this way, the primary-side switch 73 functions as a power switch for the power supply device 10.

[0065] Instead of such a configuration, a configuration may be adopted in which operating power is constantly supplied to the controller 121. In this case, for example, a power switch may be provided separately from the primary-side switch 73, and when the power switch is turned from OFF to ON by a user, the controller 121 detecting this may turn ON the power supplies to the inverter circuit 124, the DC-DC converter 125, etc.

[0066] The boost circuit 123 is a power converter that boosts the voltage of the power input unit 101 and supplies the boosted voltage to the inverter circuit 124. The inverter circuit 124 is a power converter that converts the DC voltage input from the boost circuit 123 into an AC voltage, for example, by PWM control, and supplies the converted AC power to the AC output unit 30. The effective value of the AC power supplied from the inverter circuit 124 to the AC output unit 30 is set to an effective value preset by the voltage selector switch 71. Similarly, the frequency of the AC power supplied from the inverter circuit 124 to the AC output unit 30 is set to a frequency preset by the frequency selector switch 72. The voltage input from the boost circuit 123 to the inverter circuit 124 is appropriately adjusted to a voltage corresponding to the effective value and frequency. The operations of the boost circuit 123 and the inverter circuit 124 are controlled by the controller 121. Although not shown in FIG. 8, the path through which AC power is output from the AC output unit 30 can be opened or closed based on the operation of the secondary-side switch 74.

[0067] In this way, the controller 121 changes the specifications of the AC power output from the AC output unit 30 in response to an operation performed on the operation unit 70. The "specifications" here include the effective value of the AC power output from the AC output unit 30 and the frequency of the AC power output from the AC output unit 30. Instead of this configuration, only either the effective value or the frequency may be changed in response to an operation performed on the operation unit 70.

[0068] The DC-DC converter 125 is a power converter that adjusts the voltage of the power input unit 101 and supplies the adjusted voltage to the DC output unit 32. The DC-DC converter 125 generates a voltage that matches the specifications of the device connected to the DC output unit 32, for example, a voltage of 5 V, and supplies the voltage to the DC output unit 32. The voltage adjustment by the DC-DC converter 125 may be performed based on an operation performed by a user on the operation unit 70. The operation of the DC-DC converter 125 is controlled by the controller 121. Although not shown in FIG. 8 , the path along which DC power is output from the DC output unit 32 can be opened or closed based on an operation to the secondary-side switch 74.

[0069] Each of the boost circuit 123, the inverter circuit 124, and the DC-DC converter 125 performs power conversion between the connection unit 50 and the output unit (the AC output unit 30 or the DC output unit 32), and corresponds to the "power conversion unit" in this embodiment.

[0070] The circuit configuration of the power supply device 10, including portions omitted from FIG. 8, will be described with reference to FIG. 10. In FIG. 10, dotted lines labeled "40" schematically represent battery packs 40 connected to connection portion 50. In FIG. 10, only two of the four battery packs 40 connected to power supply device 10 are shown; specifically, the battery pack 40 connected to the top row in FIG. 8 and the battery pack 40 connected one row below. For ease of explanation, the battery pack 40 shown in the top row of FIG. 10 may also be referred to as "battery pack 40A" below. The battery pack 40 shown in the bottom row of FIG. 10 may also be referred to as "battery pack 40B" below.

[0071] Each battery pack 40 is provided with an over-discharge terminal 403 and a temperature terminal 404 in addition to the pair of electrodes 401, 402 described above with reference to FIG.

[0072] The overdischarge terminal 403 is a terminal for outputting a signal indicating that the current passing through the cell 41 has exceeded a predetermined value, i.e., that an overdischarge has occurred in the battery pack 40. Inside the battery pack 40, a switching element 42 is provided at a position midway along the path connecting the overdischarge terminal 403 and the electrode 402. Under normal conditions, the switching element 42 is in a closed state. When the current passing through the cell 41 exceeds a predetermined value, a control circuit (not shown) provided inside the battery pack 40 detects this and switches the switching element 42 to an open state. As shown in FIG. 10 , when a predetermined voltage is applied to the overdischarge terminal 403 from the outside, the potential of the overdischarge terminal 403 changes depending on the open / closed state of the switching element 42. The potential of the overdischarge terminal 403 is used as a signal indicating that an overdischarge has occurred in the battery pack 40.

[0073] The temperature terminal 404 is a terminal for outputting a signal indicating the internal temperature of the battery pack 40, specifically the temperature of the cell 41, to the outside. Inside the battery pack 40, a thermistor 43 is provided at a position midway along the path connecting the temperature terminal 404 and the electrode 402. The thermistor 43 is a so-called "NTC thermistor" that decreases its electrical resistance as the detected temperature increases. As shown in FIG. 10 , when a predetermined voltage is applied to the temperature terminal 404 from the outside, the potential of the temperature terminal 404 changes depending on the electrical resistance of the thermistor 43. The potential of the temperature terminal 404 is used as a signal indicating the internal temperature of the battery pack 40.

[0074] Information indicating whether over-discharge has occurred in the battery pack 40 and the internal temperature of the battery pack 40 both correspond to "battery information" indicating the state of the battery pack 40. The over-discharge terminal 403 and the temperature terminal 404 are both terminals for outputting a signal indicating battery information (specifically, potential) to the outside of the battery pack 40, and correspond to "information terminals" in this embodiment. Furthermore, the signals output from the over-discharge terminal 403 and the temperature terminal 404 correspond to "first signals" in this embodiment.

[0075] The battery information may include information on whether an overcurrent has occurred in the battery pack 40, instead of or in addition to the information on whether an overdischarge has occurred in the battery pack 40. That is, the signal output from the overdischarge terminal 403 may indicate whether at least one of an overdischarge or an overcurrent has occurred in the battery pack 40. Furthermore, the information on whether an overdischarge has occurred in the battery pack 40 and the information on whether an overcurrent has occurred in the battery pack 40 may be output from different terminals.

[0076] First, the connection unit 50 to which the battery pack 40A is connected and the circuit configuration in the vicinity thereof will be described. As described with reference to Fig. 8, the connection unit 50 to which the battery pack 40A is connected has a regulator 122 connected to a terminal 51. The regulator 122 generates VCC1 as a voltage to be supplied to the controller 121. In addition to being supplied to the controller 121, VCC1 is also supplied to each power supply line labeled "VCC1" in Fig. 10.

[0077] Terminal 51 of connection unit 50 to which storage battery pack 40A is connected is connected not only to regulator 122 but also to regulator 122A. Regulator 122A generates a voltage VCC2 based on the potential of terminal 52 of connection unit 50 to which storage battery pack 40A is connected. VCC2 is supplied to each power supply line labeled "VCC2" in FIG. 10.

[0078] The internal circuit 100 is further provided with terminals 53 and 54 for each of the connection portions 50. The terminals 53 and 54, together with the terminals 51 and 52, are inserted into the recess 410 of the battery pack 40.

[0079] The terminal 53 is a terminal to which the over-discharge terminal 403 of the battery pack 40 is connected. The terminal 53 to which the over-discharge terminal 403, which is an information terminal, is connected corresponds to the "third terminal" in this embodiment.

[0080] A voltage of VCC2 is applied via resistor R1 to terminal 53 of connection unit 50 to which storage battery pack 40A is connected. In addition, a wire extending from terminal 53 is connected to the reference potential of regulator 122A via the primary side (light-emitting element side) of photocoupler PC1.

[0081] One end of the secondary side (light receiving element side) of the photocoupler PC1 is connected to a signal input terminal P11 of the controller 121, and the other end is connected to the reference potential of the controller 121. A voltage of VCC1 is applied to the portion between the photocoupler PC1 and the signal input terminal P11 via a resistor R5.

[0082] As described above, during normal operation when battery pack 40A is not over-discharged, switching element 42 is closed. At this time, the potential of terminal 53 is the same as the potential of terminal 52, so no current flows through the primary side of photocoupler PC1 and the secondary side of photocoupler PC1 is open. As a result, the voltage VCC1 is input to signal input terminal P11 of controller 121.

[0083] When over-discharge occurs in battery pack 40A, switching element 42 is opened. At this time, the potential of terminal 53 becomes equal to VCC2, so current flows through the primary side of photocoupler PC1 and the secondary side of photocoupler PC1 is closed. As a result, the potential of signal input terminal P11 of controller 121 drops to the reference potential of controller 121.

[0084] In this way, the potential of the signal input terminal P11 of the controller 121 changes between the reference potential of the controller 121 and VCC1 depending on whether or not over-discharge has occurred in the battery pack 40A. The controller 121 can determine whether or not over-discharge has occurred in the battery pack 40A depending on the signal input to the signal input terminal P11, i.e., the change in the potential of the signal input terminal P11. The signal input to the signal input terminal P11 can be said to be a signal (second signal) input to the controller 121, which is obtained by converting a signal (first signal) corresponding to the change in potential of the terminal 53. Furthermore, a circuit formed by resistors R1, R5, and photocoupler PC1 is a circuit for converting the first signal into the second signal, and corresponds to one of the "signal conversion units" in this embodiment.

[0085] Terminal 54 is a terminal to which temperature terminal 404 of storage battery pack 40 is connected. Terminal 54 to which temperature terminal 404, which is an information terminal, is connected corresponds to the "third terminal" in this embodiment together with terminal 53 described above.

[0086] A voltage of VCC2 is applied via resistor R2 to terminal 54 of connection unit 50 to which storage battery pack 40A is connected. In addition, a wire extending from terminal 54 is connected to a first input terminal t1 of comparator CP.

[0087] A wiring extending toward the battery pack 40B is connected to the terminal 52 of the connection unit 50 to which the battery pack 40A is connected, and a voltage of VCC2 is applied via resistors R3 and R4. The resistors R3 and R4, which are connected in series, are connected to a second input terminal t2 of the comparator CP. A wiring extending from the output terminal t3 of the comparator CP is connected to the reference potential of the regulator 122A via the primary side (light-emitting element side) of the photocoupler PC2.

[0088] One end of the secondary side (light receiving element side) of the photocoupler PC2 is connected to a signal input terminal P12 of the controller 121, and the other end is connected to the reference potential of the controller 121. A voltage of VCC1 is applied to the portion between the photocoupler PC2 and the signal input terminal P12 via a resistor R6.

[0089] The comparator CP is an element configured such that when the potential of the first input terminal t1 is equal to or greater than the potential of the second input terminal t2, the potential of the output terminal t3 becomes Low, and when the potential of the first input terminal t1 falls below the potential of the second input terminal t2, the potential of the output terminal t3 becomes High.

[0090] Under normal conditions, when the temperature of the battery pack 40A is below a predetermined temperature, the electrical resistance of the thermistor 43 becomes relatively large, and the potential of the first input terminal t1 becomes equal to or higher than the potential of the second input terminal t2. In this state, no current flows through the primary side of the photocoupler PC2, and the secondary side of the photocoupler PC2 is open. Therefore, the voltage VCC1 is input to the signal input terminal P12 of the controller 121.

[0091] When the temperature of the battery pack 40A rises and exceeds the predetermined temperature, i.e., when the battery pack 40A overheats, the electrical resistance of the thermistor 43 becomes relatively small, and the potential of the first input terminal t1 falls below the potential of the second input terminal t2. In this case, current flows through the primary side of the photocoupler PC2, and the secondary side of the photocoupler PC2 is closed. As a result, the potential of the signal input terminal P12 of the controller 121 falls to the reference potential of the controller 121.

[0092] In this way, the potential of the signal input terminal P12 of the controller 121 changes between the reference potential of the controller 121 and VCC1 depending on whether or not an overheating has occurred in the storage battery pack 40. The controller 121 can determine whether or not an overheating has occurred in the storage battery pack 40 depending on the signal input to the signal input terminal P12, i.e., the change in the potential of the signal input terminal P12. The signal input to the signal input terminal P12 can be said to be a signal (second signal) input to the controller 121, which is obtained by converting a signal (first signal) depending on the change in the potential of the terminal 54. Furthermore, a circuit formed by resistors R2, R3, R4, R6, comparator CP, and photocoupler PC2 is a circuit for converting the first signal into a second signal, and corresponds to one of the "signal conversion units" in this embodiment.

[0093] The connection unit 50 to which the battery pack 40B is connected and the circuit configuration in the vicinity thereof are generally the same as the configuration described above for the battery pack 40A. In the circuit portion connected to the battery pack 40B, the regulator 122A described above is replaced with a regulator 122B. The regulator 122B generates a voltage VCC3 based on the potential of the terminal 52 of the connection unit 50 to which the battery pack 40B is connected. VCC3 is supplied to each power supply line labeled "VCC3" in FIG. 10.

[0094] A signal indicating whether or not over-discharge has occurred in the battery pack 40B is sent from the secondary side of the photocoupler PC1, as in the case of the battery pack 40A, and input to a signal input terminal P21 of the controller 121. The controller 121 can determine whether or not over-discharge has occurred in the battery pack 40B according to the signal input to the signal input terminal P21, i.e., a change in the potential of the signal input terminal P21.

[0095] Similarly to the case of the battery pack 40A, a signal indicating whether an overheating has occurred in the battery pack 40B is sent from the secondary side of the photocoupler PC2 and input to a signal input terminal P22 of the controller 121. The controller 121 can determine whether an overheating has occurred in the battery pack 40B according to the signal input to the signal input terminal P22, i.e., a change in the potential of the signal input terminal P22.

[0096] Although some circuits are not shown in FIG. 10 , circuits constituting the signal conversion unit described above are individually provided corresponding to each of the four connection units 50 of the power supply device 10. The controller 121 has, corresponding to each of the four connection units 50, a signal input terminal to which a signal indicating whether or not over-discharge has occurred in the battery pack 40 is input, and a signal input terminal to which a signal indicating whether or not over-heating has occurred in the battery pack 40 is input. In addition, a regulator similar to regulator 122A and regulator 122B is provided corresponding to each of the four connection units 50. Each regulator generates a voltage required for operation of the signal conversion unit based on the potential of terminal 52 of the corresponding connection unit 50, and supplies the voltage to each unit.

[0097] With the above configuration, the controller 121 can constantly determine whether or not over-discharge or over-temperature has occurred in each of the plurality of connected battery packs 40.

[0098] The configuration of the battery pack 40, which includes the information terminals, the overdischarge terminal 403 and the temperature terminal 404, is conventionally known. A typical circuit configuration for extracting battery information from the information terminals of the battery pack 40 is the configuration of a comparative example shown in FIG. 11 . Unlike the present embodiment, this comparative example has only one connection unit 50, and only a single battery pack 40 is connected to the battery device. The potential of terminal 53 is directly input to signal input terminal P11 of the controller 121. The potential of terminal 54 is directly input to signal input terminal P12 of the controller 121.

[0099] Even with this configuration, the controller 121 can determine whether over-discharge or over-temperature has occurred in the storage battery pack 40. Therefore, it seems that a simple circuit configuration similar to that shown in FIG. 11 may also be employed for a configuration having multiple connection parts 50 as in this embodiment.

[0100] However, when the circuit configuration of Fig. 11 is employed, it becomes impossible to accurately determine the state of each battery pack 40 based on the potential of the information terminal, for the following reason.

[0101] In a configuration in which a plurality of battery packs 40 are connected in series as in this embodiment, the potential of the negative electrode 402 differs for each battery pack 40. Therefore, except for the battery pack 40 arranged closest to the power input unit 102 (the lowest stage in FIG. 8 ), the potential of the electrode 402 does not match the reference potential of the controller 121. As a result, the correspondence between the potentials of the information terminals (the overdischarge terminal 403 and the temperature terminal 404) input to the controller 121 and the state of the battery pack 40 changes, and the controller 121 is unable to grasp the state of the battery pack 40.

[0102] Furthermore, the potential of the electrode 402 of the battery pack 40 increases as the connection position of the battery pack 40 approaches the power input unit 101 (the uppermost stage in FIG. 8). Therefore, in a battery pack 40 that is positioned closest to the power input unit 101 (the uppermost stage in FIG. 8), the potentials of the overdischarge terminal 403 and the temperature terminal 404 may become too high, exceeding the input range of the controller 121.

[0103] Therefore, the power supply device 10 according to this embodiment solves the above problems by employing the circuit configuration described with reference to FIG.

[0104] As mentioned above, in this embodiment, the signal (first signal) from the information terminals (over-discharge terminal 403 and temperature terminal 404) of the battery pack 40 is not directly input to the controller 121, but rather the signal (second signal) converted by a signal conversion unit such as a photocoupler PC1 is input to the controller 121.

[0105] For example, for a signal from the overdischarge terminal 403, the photocoupler PC1 operates based on the voltage between terminals 52 and 53, and the signal generated by the operation of the photocoupler PC1 is input to the controller 121 as the second signal. Also, for a signal from the temperature terminal 404, the comparator CP and the photocoupler PC2 operate based on the voltage between terminals 52 and 54, and the signal generated by the operation of the photocoupler PC2 is input to the controller 121 as the second signal. In either case, the signal conversion unit converts the first signal to the second signal so that the second signal input to the controller 121 is a signal based on the voltage between terminal 52, which is the second terminal, and terminals 53 and 54, which are the third terminals. This allows the controller 121 to accurately grasp the state of any of the multiple storage battery packs 40 connected in series, based on the second signal.

[0106] Furthermore, the second signal after conversion by the signal conversion unit may be generated as a signal based on the voltage between the second terminal (terminal 52) and the third terminal (terminals 53, 54) as in this embodiment, or may be generated as a signal based on the voltage between the first terminal (terminal 51) and the third terminal (terminals 53, 54).

[0107] A photocoupler PC1, which is an insulating element, is interposed between terminal 53 and controller 121. In addition, a photocoupler PC2, which is an insulating element, is interposed between terminal 54 and controller 121. In this manner, terminals 53 and 54, which are third terminals, are electrically insulated from the portion of controller 121 to which the second signal is input. For this reason, even if the potential of some of the overdischarge terminals 403 and temperature terminals 404 is high when storage battery packs 40 are connected in series, a high voltage exceeding the input range of signal input terminals P11 and the like of controller 121 will not be applied.

[0108] The signal conversion unit interposed between the terminals 52, 53 and the controller 121 may be configured as a circuit including a comparator CP, a resistor R1, etc., as in the present embodiment, but at least a part of the signal conversion unit may be configured as a control circuit such as a microcomputer. In this case, the controller 121 may grasp the state of each storage battery pack 40 based on signals transmitted and received between the controller 121 and the control circuit. An insulating element such as a photocoupler PC1 may be provided as part of the control circuit, or may be provided between the control circuit and the controller 121.

[0109] A specific flow of processing executed mainly by the controller 121 will be described with reference to Fig. 12. The series of processing shown in the flowchart in the figure is started when the primary-side switch 73, which corresponds to the power switch, is switched ON.

[0110] In the first step S01 of this process, the power supply device 10 is turned on, and power is supplied from the storage battery pack 40 to each unit including the controller 121. The controller 121 is activated by the power supply and automatically starts executing the processes from step S02 onwards.

[0111] In step S02 following step S01, it is determined whether or not over-discharge has been detected in any of the battery packs 40. The controller 121 constantly monitors whether or not over-discharge has occurred in each of the battery packs 40 connected to the power supply device 10, based on a signal input from the terminal 53 via the photocoupler PC1. If it is determined that over-discharge has occurred in any of the battery packs 40, the process proceeds to step S16, which will be described later. If it is determined that over-discharge has not occurred in any of the battery packs 40, the process proceeds to step S03.

[0112] In step S03, it is determined whether an excessive temperature rise has been detected in any of the battery packs 40. The controller 121 constantly monitors whether an excessive temperature rise has occurred in each of the battery packs 40 connected to the power supply device 10, based on a signal input from the terminal 54 via the photocoupler PC2. If it is determined that an excessive temperature rise has occurred in any of the battery packs 40, the process proceeds to step S16. If it is determined that an excessive temperature rise has not occurred in any of the battery packs 40, the process proceeds to step S04.

[0113] In step S04, output of AC power from the AC output unit 30 and output of DC power from the DC output unit 32 are started. As described above, the controller 121 controls the operation of each of the boost circuit 123, the inverter circuit 124, and the DC-DC converter 125, thereby adjusting the power output from the AC output unit 30 etc.

[0114] In step S05 following step S04, the input voltage is detected. The "input voltage" here refers to the DC voltage input to the boost circuit 123 and the like from all of the storage battery packs 40 connected in series with one another, and more specifically, refers to the voltage applied between the power input unit 101 and the power input unit 102. The input voltage can be detected, for example, by a voltage sensor (not shown) provided in the power supply device 10.

[0115] In step S06 following step S05, the available output power is calculated. The "available output power" refers to the upper limit of power that is permitted to be output from the power supply device 10 to the outside via the output units (the AC output unit 30 and the DC output unit 32). In this embodiment, the controller 121 calculates the "available output power" as a power value obtained by multiplying a predetermined rated current value by the input voltage detected in step S05. The "rated current value" used in calculating the available output power is a fixed value that is preset according to the circuit configuration of the power supply device 10. For example, the smallest value of the rated currents of the elements that make up the power conversion unit is preset as the "rated current value." The available output power calculated in this manner changes each time based on the number of storage battery packs 40 connected to the power supply device 10, the inter-terminal voltage of each storage battery pack 40, etc.

[0116] In step S07 following step S06, a process is performed in which the value of the available output power calculated in step S06 is notified to the user. The controller 121 notifies the user of the value of the available output power by displaying it on the screen of the notification unit 60. This allows the user to easily know what kind of load can be connected to the power supply device 10. In this way, the information notified to the user by the notification unit 60 includes the amount of power that can be output from the output unit.

[0117] The value of the available output power may be calculated separately for both the case where AC power is output from the AC output unit 30 and the case where DC power is output from the DC output unit 32, and each value may be displayed on the notification unit 60.

[0118] In step S08 following step S07, the input current is detected. The "input current" here refers to a direct current input to the boost circuit 123 and the like from all of the storage battery packs 40 connected in series with one another, and more specifically, refers to a current flowing between the power input unit 101 and the power input unit 102. The input current can be detected, for example, by a current sensor (not shown) provided in the power supply device 10.

[0119] In step S09 following step S08, the power consumption is calculated. Here, "power consumption" refers to the value of the power output from the output section of the power supply device 10 to the outside. The controller 121 calculates the current power consumption value, for example, by multiplying the input voltage value detected in step S05 by the input current value detected in step S08.

[0120] In step S10 following step S09, it is determined whether the power consumption calculated in step S09 exceeds the available output power calculated in step S06. If the power consumption exceeds the available output power, the process proceeds to step S16. If the power consumption is equal to or less than the available output power, the process proceeds to step S11.

[0121] In step S11, similar to step S02, it is determined again whether over-discharge has been detected in any of the battery packs 40. If it is determined that over-discharge has occurred in any of the battery packs 40, the process proceeds to step S16. If it is determined that over-discharge has not occurred in any of the battery packs 40, the process proceeds to step S12.

[0122] In step S12 following step S11, similar to step S03, it is determined again whether an excessive temperature rise has been detected in any of the battery packs 40. If it is determined that an excessive temperature rise has occurred in any of the battery packs 40, the process proceeds to step S16. If it is determined that an excessive temperature rise has not occurred in any of the battery packs 40, the process proceeds to step S13.

[0123] In step S13, if the primary-side switch 73 corresponding to the power switch remains ON, the processing from step S05 onwards is executed again. If the primary-side switch 73 is turned OFF, the power supply from the storage battery pack 40 is stopped. In this case, the output of power from the output unit is stopped in step S14, and the power supply device 10 is turned OFF in step S15.

[0124] If it is determined in step S02 or step S11 that over-discharge has occurred in any of the battery packs 40, or if it is determined in step S03 or step S12 that excessive temperature rise has occurred in any of the battery packs 40, this means that an abnormality has occurred in one of the battery packs 40, and it is therefore undesirable to continue outputting power from the power supply device 10. Furthermore, if it is determined in step S10 that the power consumption exceeds the available power output, this means that excessive power is being output from the power supply device 10, and it is also undesirable to continue outputting power from the power supply device 10. For this reason, in step S16, a process is performed to notify the user that an abnormality has occurred in the power supply device 10. The controller 121, for example, displays a character string or the like indicating that an abnormality has occurred on the screen of the notification unit 60.

[0125] In this way, the information notified to the user by the notification unit 60 includes information indicating that an abnormality has occurred in the storage battery pack 40 and information indicating that the power output from the output unit has exceeded the upper limit value (outputtable power).

[0126] After the process of step S16 is completed, the process proceeds to step S14. In this case, the controller 121 stops the operation of the boost circuit 123, which is a power conversion unit, and thereby stops the output of AC power from the AC output unit 30 and the output of DC power from the DC output unit 32. In the subsequent step S15, the controller 121 automatically shuts down the power supply device 10, thereby turning the power supply device 10 off. In this way, when the power output from the output unit exceeds the upper limit (outputtable power), the controller 121 according to this embodiment performs a process to stop the output of power from the output unit.

[0127] It should be noted that even after the process of step S15 is performed, the notification unit 60 may continue to provide notification.

[0128] A second embodiment will be described. This embodiment differs from the first embodiment in the configuration of the internal circuit 100. Figure 13 shows a schematic diagram of the configuration of a power supply device 10 according to this embodiment in a manner similar to that shown in Figure 8.

[0129] 13 , in the internal circuit 100 of this embodiment, a relay RL is provided at a position midway along a path through which current is output from the storage battery pack 40. The relay RL is a contact-type mechanical relay. The relay RL is provided at a position in which it is arranged in series with the storage battery pack 40 at the connection unit 50, and the relay RL and the entire storage battery pack 40 are electrically connected in parallel to the diode 111. In other words, the connection path 110 including the diode 111 is provided as a current path that bypasses the relay RL and the entire connection unit 50.

[0130] Each of the relays RL provided corresponding to the four connection parts 50 is connected to the controller 121 and performs an opening and closing operation based on a signal from the controller 121. During normal operation when no abnormality occurs in the storage battery pack 40, the relays RL are closed. On the other hand, when an abnormality in the storage battery pack 40 is detected, the relay RL provided corresponding to that storage battery pack 40 is switched to an open state. As a result, the relay RL cuts off the path through which current is output from the storage battery pack 40 in which the abnormality has occurred. The relay RL corresponds to the "abnormality cutoff unit" in this embodiment. As the abnormality cutoff unit, a switching element such as a MOFSET may be used instead of the relay RL as in this embodiment.

[0131] A specific flow of processing executed in this embodiment will be described with reference to Fig. 14. The series of processing shown in the flowchart in this figure is executed in place of the series of processing shown in Fig. 12.

[0132] The flowchart in Fig. 14 is obtained by adding the processes of steps S21 to S29 to the flowchart in Fig. 12. In the following, differences from the first embodiment in Fig. 12 will be mainly described, and descriptions of points in common with the first embodiment will be omitted as appropriate.

[0133] In this embodiment, if it is determined in step S02 that over-discharge has occurred in any of the battery packs 40, or if it is determined in step S03 that overheating has occurred in any of the battery packs 40, the process proceeds to step S21. In step S21, it is determined whether an abnormality has occurred in all of the battery packs 40 connected to the power supply device 10, or whether an abnormality has occurred in only some of the battery packs 40.

[0134] If an abnormality has occurred in all of the multiple storage battery packs 40 connected to the power supply device 10, the process proceeds to step S16. In this case, it means that there is no storage battery pack 40 that can normally supply power. Therefore, as described above, the notification unit 60 notifies the user that an abnormality has occurred, and the output of power from the power supply device 10 is stopped.

[0135] In step S21, if an abnormality has occurred in only some of the multiple battery packs 40, i.e., if there is a battery pack 40 that can normally supply power, the process proceeds to step S22. In step S22, the relay RL corresponding to the abnormal battery pack 40 is switched to the open state, and the current output path from that battery pack 40 is interrupted. Note that the relay RL corresponding to the normal battery pack 40 remains closed. Therefore, the supply of power from the normal battery packs 40 continues thereafter.

[0136] The terminal 51 and the terminal 52 to which the abnormal storage battery pack 40 is connected are electrically connected by the connection path 110, just as when the abnormal storage battery pack 40 is not connected. Therefore, the paths for supplying power from the other storage battery packs 40 are not interrupted. In this way, the connection path 110 of this embodiment can be said to electrically connect the terminal 51 and the terminal 52 to which the abnormal storage battery pack 40 is connected when an abnormality in the storage battery pack 40 is detected.

[0137] In the determination of step S21, if the remaining battery charge of a storage battery pack 40 becomes 0 (or a predetermined value or less), it may be determined that an abnormality has occurred in that storage battery pack 40. With this configuration, if the remaining battery charge of one of the storage battery packs 40 among the multiple storage battery packs 40 connected to the power supply device 10 becomes 0, it becomes possible to continue using the power supply device 10 using the output from the remaining storage battery packs 40 without removing that storage battery pack 40.

[0138] In step S23 following step S22, the notification unit 60 displays a message to notify the user that an abnormality has occurred in one of the storage battery packs 40. A message urging the user to remove or replace the storage battery pack 40 may also be displayed on the notification unit 60.

[0139] After step S23, the processes from step S04 onwards are performed. As a result, power continues to be output from the power supply device 10 using only the storage battery packs 40 that are not malfunctioning. Note that, because the output path from the storage battery pack 40 in which the malfunction has occurred is blocked by the relay RL, the input voltage detected in step S05 becomes a lower voltage than before. In addition, the value of the available output power reported in step S07 changes to a value corresponding to the number of normal storage battery packs 40. This allows the user to know the value of the available output power, which changes depending on the state of the storage battery packs 40, in real time.

[0140] If it is determined in step S11 that over-discharge has occurred in any of the battery packs 40, the process proceeds to step S24. Thereafter, the processes executed in steps S24, S25, and S26 are the same as the processes executed in steps S21, S22, and S23. As a result, the power supply from the abnormal (over-discharged) battery pack 40 is stopped, a notification to that effect is issued, and the power supply from the normal battery packs 40 is continued. After step S26, the processes from step S12 onwards are executed.

[0141] If it is determined in step S12 that an excessive temperature rise has occurred in any of the battery packs 40, the process proceeds to step S27. Thereafter, the processes executed in steps S27, S28, and S29 are the same as the processes executed in steps S21, S22, and S23. As a result, the power supply from the battery pack 40 in which the abnormality (excessive temperature rise) has occurred is stopped, and a notification to that effect is issued, while the power supply from the normal battery packs 40 is continued. After step S29, the processes from step S13 onwards are executed.

[0142] As described above, in the power supply device 10 according to this embodiment, even if an abnormality such as overheating occurs in some of the multiple connected storage battery packs 40, the remaining normal storage battery packs 40 can be used to continue supplying power to the outside from the power supply device 10. This effect can be said to be another effect obtained by making it possible to change the number of storage battery packs 40 connected to the connection unit 50 as needed.

[0143] Although the above operations are performed automatically by the controller 121, they may also be performed manually by the user. For example, a manually operated open / close switch may be provided as the abnormality cutoff unit instead of the relay RL. In this case, the user can cut off the power supply from the abnormal storage battery pack 40 by switching some of the open / close switches to the open state in accordance with the status of each storage battery pack 40 displayed on the notification unit 60, for example.

[0144] Various modifications and improvements can be made to the above-described power supply device 10. For example, the controller 121 may change the operation of a power conversion unit such as the inverter circuit 124 depending on the magnitude of a load (for example, the power consumption of an electrical device) connected to an output unit such as the AC output unit 30.

[0145] For example, if the power consumption of an electrical device connected to power supply device 10 is large, boost circuit 123 may boost the voltage to a higher level, or the duty of PWM control in inverter circuit 124 may be increased. In this way, by appropriately changing the operation of the power conversion unit according to the power that needs to be output, it becomes possible to more efficiently supply power from power supply device 10.

[0146] The above description has been given of an example in which the power supply device 10 is a general-purpose power supply device to which various external devices can be connected. However, the configuration of the power supply device 10 described above can also be applied to a power supply device that is integrated with an electrical device, such as a power supply circuit built into a portable power tool. Examples of such electrical devices include large power tools. By applying the technology of the present invention described above to a power supply unit built into a power tool or an external power supply unit, it becomes possible to obtain a large output corresponding to the connected battery pack, regardless of the specifications, number, or remaining battery charge of the battery pack.

[0147] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0148] 10: Power supply 30: AC output section 32: DC output section 40: Battery pack 50: Connection 51, 52, 53, 54: Terminals 100: Internal circuit 110: Connection path 111: Diode

Claims

1. a plurality of connection portions to which the storage battery packs are connected; an internal circuit that electrically connects the battery packs connected to the connection portions in series; an output unit that outputs power from the storage battery pack, For each of the connection parts, the internal circuitry a first terminal to which one electrode of the storage battery pack is connected; a second terminal to which the other electrode of the battery pack is connected; a connection path that electrically connects the first terminal and the second terminal when the storage battery pack is not connected to the connection portion, a power conversion unit that performs power conversion between the connection unit and the output unit; the output unit includes an AC output unit that outputs AC power, Further provided is a notification unit that notifies a user of information, The power supply device, wherein the notification unit notifies the amount of power that can be output from the output unit.

2. a control unit that controls the operation of the power supply device; An operation unit that is a part operated by a user, The control unit The power supply device according to claim 1 , wherein the specifications of the AC power output from the AC output unit are changed in response to an operation performed on the operation unit.

3. 3. The power supply device according to claim 2, wherein the specifications include at least one of an effective value of the AC power output from the AC output unit and a frequency of the AC power output from the AC output unit.

4. changing the operation of the power conversion unit in accordance with the magnitude of the load connected to the output unit; The power supply device according to any one of claims 1 to 3.

5. Further, a control unit is provided to control the operation of the power supply device. When the power output from the output unit exceeds an upper limit value, The power supply device according to claim 1 , wherein the control unit stops the output of power from the output unit.

6. The power supply device according to claim 1 , wherein the notification unit notifies that an abnormality has occurred in the battery pack.

7. The power supply device according to claim 1 , wherein the notification unit notifies that the power output from the output unit has exceeded an upper limit value.

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