charger

Abstract

This technology provides a charger that can easily determine compatibility with other chargers. [Solution] The charger comprises a housing to which the battery pack is mounted by slidably receiving the battery pack along a predetermined first direction, and a plurality of device-side terminals, each having a plate shape parallel to the first direction and parallel to a second direction from the battery pack toward the housing, and engaging with the battery-side terminals of the battery pack mounted on the housing. The plurality of device-side terminals comprises two charging terminals for charging the battery pack from the charger, and two signal terminals for signal communication between the charger and the battery pack. The two charging terminals are spaced apart from each other in a third direction perpendicular to the first and second directions. Each of the two signal terminals is positioned on one side of a space partitioned by a virtual plane that bisects the space between the two charging terminals in the third direction.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a charger.

Background Art

[0002] Patent Document 1 discloses a charger to which a battery pack having a battery-side terminal is detachably attached. The charger includes a housing that slidably receives the battery pack along a predetermined first direction, and a plurality of device-side terminals each having a plate shape parallel to the first direction and parallel to a second direction from the battery pack toward the housing, and engaging with the battery-side terminal of the battery pack attached to the housing. The plurality of device-side terminals include two charging terminals for charging from the charger to the battery pack, and three signal terminals for signal communication between the charger and the battery pack. The two charging terminals are spaced apart from each other in a third direction orthogonal to the first direction and the second direction. Each of the three signal terminals is disposed between the two charging terminals. The plurality of device-side terminals are arranged at substantially equal intervals in the third direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There are situations where a user of a charger determines whether the charger they use is compatible with other chargers. Assuming this situation, it is desirable that the charger can easily determine whether it is compatible with other chargers. In this specification, a technology for realizing a charger that can easily determine whether it is compatible with other chargers is provided.

Means for Solving the Problems

[0005] The charger disclosed herein is a charger to which a battery pack having battery-side terminals can be attached and detached. The charger comprises a housing to which the battery pack is attached by slidably receiving the battery pack along a predetermined first direction, and a plurality of device-side terminals, each having a plate shape parallel to the first direction and parallel to a second direction from the battery pack toward the housing, and engaging with the battery-side terminals of the battery pack attached to the housing. The plurality of device-side terminals comprises two charging terminals for charging the battery pack from the charger, and two signal terminals for signal communication between the charger and the battery pack. The two charging terminals are spaced apart from each other in a third direction perpendicular to the first and second directions. Each of the two signal terminals is located on one side of a space defined by a virtual plane that bisects the space between the two charging terminals in the third direction.

[0006] Chargers with multiple device-side terminals arranged at approximately equal intervals, such as the one disclosed in Patent Document 1, are commonly available. In this configuration, two signal terminals are located near one charging terminal. The other charging terminal is located at a distance from the other device-side terminals (i.e., the charging terminal and the two signal terminals). As a result, the layout of the device-side terminals is clearly different from that of commonly available chargers (i.e., chargers with multiple device-side terminals arranged at approximately equal intervals). This makes it possible to determine from the difference in appearance that the charger of this application and commonly available chargers are not compatible. Therefore, the above configuration makes it possible to realize a charger in which compatibility with other chargers can be easily determined. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows the battery pack 4 of the charging system 2 according to the embodiment in a state where it has been removed from the charger 6. [Figure 2]This figure shows the battery pack 4 attached to the charger 6 in the charging system 2 according to the embodiment. [Figure 3] This figure shows the charging system 2 according to the embodiment, with the battery pack 4 removed from the electric work machine 16. [Figure 4] This figure shows the charging system 2 according to the embodiment, with the battery pack 4 attached to the electric work machine 16. [Figure 5] This is an exploded view of the battery pack 4 according to the embodiment. [Figure 6] This is a view of the battery module 22 of the battery pack 4 according to the embodiment, seen from the front, upper, and right. [Figure 7] This is a view of the battery module 22 of the battery pack 4 according to the embodiment, seen from the rear, lower left. [Figure 8] This is a perspective view of the battery-side terminal 12 of the battery pack 4 according to the embodiment. [Figure 9] This is a view from above of the battery module 22 of the battery pack 4 according to the embodiment. [Figure 10] This is a view of the upper case 26 of the battery pack 4 according to the embodiment, seen from the rear, upper, and right. [Figure 11] This is a view of the battery pack 4 according to the embodiment, seen from above. [Figure 12] This is a view of the upper case 26 of the battery pack 4 according to the embodiment, seen from the front, lower right. [Figure 13] This is an exploded view of the charger 6 according to the embodiment. [Figure 14] This is a rear view of a cross-section of the charger 6 according to the embodiment, perpendicular to the front-to-back direction. [Figure 15] This figure shows a magnified view of region EA in Figure 14. [Figure 16] This is a perspective view of the connection terminal 228 of the charger 6 according to the embodiment. [Figure 17] This is a view of the upper surface of the charger 6 according to the embodiment, along the direction perpendicular to the terminal mounting surface 10 (i.e., the second direction D2). [Figure 18]This is a diagram showing the state in which the battery-side terminal 12 and the device-side terminal 8 engage with each other during the process of attaching the battery pack 4 according to the embodiment to the charger 6. [Figure 19] This is a diagram showing the positional relationship between the battery-side terminal 12 and the device-side terminal 8 when the battery pack 4 according to the embodiment is attached to the charger 6. [Figure 20] This is a diagram schematically showing the electrical circuit formed between the battery pack 4 and the charger 6 when the battery pack 4 according to the embodiment is attached to the charger 6. [Figure 21] This is a diagram showing the positional relationship between the battery-side terminal 12 and the device-side terminal 18 when the battery pack 4 according to the embodiment is attached to the electric working machine 16. [Figure 22] This is a diagram schematically showing the electrical circuit formed between the battery pack 4 and the electric working machine 16 when the battery pack 4 according to the embodiment is attached to the electric working machine 16.

Embodiments for Carrying Out the Invention

[0008] Typical and non-limiting specific examples of the present invention will be described in detail below with reference to the drawings. This detailed description is merely intended to show those skilled in the art the details for implementing preferred examples of the present invention, and is not intended to limit the scope of the present invention. Also, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide a further improved charger.

[0009] Also, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, and are described only for the purpose of explaining typical specific examples of the present invention. Further, the various features of the following typical specific examples, as well as the various features described in the claims, do not have to be combined as shown in the specific examples described here or in the order listed.

[0010] All features described in this specification and / or in the claims are intended to be disclosed separately and independently of each other, as limitations on the initial disclosure and on the specific matters described in the claims, apart from the configurations of the features described in the embodiments and / or in the claims. Further, all descriptions of numerical ranges and groups or collections are made with the intention of disclosing intermediate configurations as limitations on the initial disclosure and on the specific matters described in the claims.

[0011] In one or more embodiments, in a fourth direction opposite to the first direction, the positions of the ends of each of the two charging terminals in the fourth direction may be aligned. The position of the end of each of the two signal terminals in the fourth direction may be offset in one of the first direction and the fourth direction with respect to the position of the end of each of the two charging terminals in the fourth direction.

[0012] According to the above configuration, the position of each of the two signal terminals is offset in the first direction (or the fourth direction) with respect to the position of each of the two charging terminals. Therefore, it is easier for the user to distinguish between the signal terminals and the charging terminals.

[0013] In one or more embodiments, the position of the end of each of the two signal terminals in the fourth direction may be offset in the fourth direction with respect to the position of the end of each of the two charging terminals in the fourth direction.

[0014] According to the above configuration, the position of each of the two signal terminals is offset in the fourth direction with respect to the position of each of the two charging terminals. Therefore, it is easier for the user to distinguish between the signal terminals and the charging terminals.

[0015] In one or more embodiments, the housing may include a terminal mounting surface facing the battery pack mounted on the housing, on which the plurality of device-side terminals are provided, and a plurality of protrusions projecting toward the battery pack from the terminal mounting surface. Each of the two charging terminals may protrude toward the battery pack from a location on the terminal mounting surface where the protrusions are provided. Each of the two signal terminals may protrude toward the battery pack from a location on the terminal mounting surface where the protrusions are not provided.

[0016] With the above configuration, terminals protruding from areas of the terminal mounting surface that have protrusions can be identified as charging terminals, and terminals protruding from areas of the terminal mounting surface that do not have protrusions can be identified as signal terminals. Therefore, it becomes easier for the user to distinguish between signal terminals and charging terminals.

[0017] In one or more embodiments, the housing may include a terminal mounting surface facing the battery pack mounted on the housing, on which the plurality of device-side terminals are provided, and a plurality of protrusions projecting toward the battery pack from the terminal mounting surface. Each of the two signal terminals may project toward the battery pack from a portion of the terminal mounting surface where the protrusions are not provided. At least one of the protrusions may be positioned so as not to be in contact with the plurality of device-side terminals on the other side of the space partitioned by the virtual plane.

[0018] With the above configuration, a battery pack having a recess corresponding to a protrusion can be attached to the charger. On the other hand, if one attempts to attach a battery pack that does not have a recess corresponding to a protrusion to the charger, the protrusion will interfere with the battery pack, making it impossible to attach the battery pack to the charger. This prevents unintended battery packs from being attached to the charger.

[0019] Another charger disclosed herein may be a charger to which a battery pack having battery-side terminals can be attached and detached. The charger may include a housing to which the battery pack is attached by sliding the battery pack along a predetermined first direction, and a plurality of device-side terminals, each having a plate shape parallel to the first direction and parallel to a second direction from the battery pack toward the housing, and engaging with the battery-side terminals of the battery pack attached to the housing. The plurality of device-side terminals may include two charging terminals for charging the battery pack from the charger, and two signaling terminals for signal communication between the charger and the battery pack. The housing may include a terminal mounting surface facing the battery pack attached to the housing, on which the plurality of device-side terminals are provided, and a plurality of protrusions projecting toward the battery pack from the terminal mounting surface. Each of the two charging terminals may project toward the battery pack from a location on the terminal mounting surface where the protrusions are provided. Each of the two signal terminals may protrude toward the battery pack from a portion of the terminal mounting surface where the protrusion is not provided.

[0020] With the above configuration, terminals protruding from areas of the terminal mounting surface that have protrusions can be identified as charging terminals, and terminals protruding from areas of the terminal mounting surface that do not have protrusions can be identified as signal terminals. Therefore, it becomes easier for the user to distinguish between signal terminals and charging terminals.

[0021] Another charger disclosed herein may be a charger to which a battery pack having battery-side terminals can be attached and detached. The charger may include a housing to which the battery pack is attached by sliding the battery pack along a predetermined first direction, and a plurality of device-side terminals, each having a plate shape parallel to the first direction and parallel to a second direction from the battery pack toward the housing, and engaging with the battery-side terminals of the battery pack attached to the housing. The plurality of device-side terminals may include two charging terminals for charging the battery pack from the charger, and two signal terminals for signal communication between the charger and the battery pack. The housing may include a terminal mounting surface facing the battery pack attached to the housing, on which the plurality of device-side terminals are provided, and a plurality of protrusions projecting toward the battery pack from the terminal mounting surface. Each of the two signal terminals may project toward the battery pack from a portion of the terminal mounting surface where the protrusions are not provided. At least one of the protrusions may be arranged so as not to be in contact with the plurality of device-side terminals.

[0022] With the above configuration, a battery pack having a recess corresponding to a protrusion can be attached to the charger. On the other hand, if one attempts to attach a battery pack that does not have a recess corresponding to a protrusion to the charger, the protrusion will interfere with the battery pack, making it impossible to attach the battery pack to the charger. This prevents unintended battery packs from being attached to the charger.

[0023] (Example; Charging System 2) As shown in Figures 1 and 2, the charging system 2 comprises a battery pack 4 and a charger 6 for charging the battery pack 4. The charger 6 has a terminal mounting surface 10 on which a plate-shaped device-side terminal 8 protrudes. The battery pack 4 is attached to the charger 6 by sliding it in a direction parallel to the terminal mounting surface 10. When the battery pack 4 is attached to the charger 6, the device-side terminal 8 engages with the battery-side terminal 12 (see Figure 9) of the battery pack 4, enabling charging of the battery pack 4 from the charger 6. The battery pack 4 attached to the charger 6 is removed from the charger 6 by sliding it in the opposite direction to when it was attached. The charger 6 also has a display unit 14 that indicates the charging status of the battery pack 4 (for example, whether it is charging or not).

[0024] As shown in Figures 3 and 4, the battery pack 4 is detachably attached to the electric work implement 16 (partially shown) and functions as a power source that supplies power to the electric work implement 16. The electric work implement 16 is, for example, an electric drill, electric grinder, electric circular saw, electric chainsaw, electric reciprocating saw, electric lawnmower, electric brush cutter, or electric blower. The electric work implement 16 has a terminal mounting surface 20 from which plate-shaped equipment-side terminals 18 protrude. The battery pack 4 is attached to the electric work implement 16 by sliding it in a direction parallel to the terminal mounting surface 20. When the battery pack 4 is attached to the electric work implement 16, the equipment-side terminals 18 engage with the battery-side terminals 12 of the battery pack 4 (see Figure 9), enabling discharge from the battery pack 4 to the electric work implement 16. The battery pack 4 attached to the electric work implement 16 is removed from the electric work implement 16 by sliding it in the opposite direction to when it was attached.

[0025] In this embodiment, the direction in which the battery pack 4 is slid when attaching it to the charger 6 (or electric work machine 16) is defined as the first direction D1. The direction perpendicular to the first direction D1, toward the terminal mounting surface 10 of the charger 6 (or the terminal mounting surface 20 of the electric work machine 16), is defined as the second direction D2. The direction perpendicular to the first direction D1 and the second direction D2, toward the position of the battery pack 4 as seen from the display unit 14 when the battery pack 4 is attached to the charger 6, is defined as the third direction D3. The direction opposite to the first direction D1 is defined as the fourth direction D4. The fourth direction D4 can also be said to be the direction in which the battery pack 4 is slid when removing it from the charger 6 (or electric work machine 16).

[0026] (Battery pack 4 configuration) First, we will explain focusing on the battery pack 4. Here, we define the forward, backward, up, down, left, and right directions relative to the battery pack 4. Specifically, the direction that coincides with the aforementioned first direction D1 (i.e., the direction in which the battery pack 4 is slid when attaching it to the charger 6 or electric work machine 16) is defined as the rear direction of the battery pack 4. The direction that coincides with the aforementioned fourth direction D4 (i.e., the direction in which the battery pack 4 is slid when removing it from the charger 6 or electric work machine 16) is defined as the front direction of the battery pack 4. The direction that coincides with the aforementioned second direction D2 (i.e., the direction perpendicular to the first direction D1, and moving from the battery pack 4 toward the terminal mounting surface 10 or terminal mounting surface 20) is defined as the upward direction of the battery pack 4. The direction opposite to the upward direction of the battery pack 4 is defined as the downward direction of the battery pack 4. The direction that coincides with the aforementioned third direction D3 (i.e., the direction perpendicular to the first direction D1 and the second direction D2, and the direction in which the battery pack 4 is located as seen from the display unit 14) is defined as the right direction of the battery pack 4. The direction opposite to the right direction of the battery pack 4 is defined as the left direction of the battery pack 4. Figures 5-12, which illustrate only the battery pack 4, show the front, back, up, down, left, and right directions relative to the battery pack 4.

[0027] As shown in Figure 5, the battery pack 4 comprises a battery module 22 and an outer case 24 that houses the battery module 22. The outer case 24 has a roughly rectangular parallelepiped shape with a front, rear, top, bottom, left, and right side. The outer case 24 is divided into an upper case 26 and a lower case 28. The upper case 26 and the lower case 28 are fixed to each other by four screws 30.

[0028] As shown in Figures 6 and 7, the battery module 22 comprises five battery cells 32, a cell cover 34, and a circuit board 36. The battery cells 32 are cylindrical secondary battery cells, such as lithium-ion battery cells, with a positive electrode formed at one end and a negative electrode formed at the other end. The rated voltage of the battery cells 32 is, for example, 3.6[V]. The cell cover 34 is made of an insulating material, such as plastic. The cell cover 34 covers the top of the five battery cells 32. The lower surface of the cell cover 34 has a shape that conforms to the outer circumferential surface of each of the battery cells 32. Each of the battery cells 32 is positioned by the lower surface of the cell cover 34 contacting each of the battery cells 32. Each of the battery cells 32 has its longitudinal direction aligned with the left-right direction and is arranged so as to be aligned with adjacent battery cells 32 in the front-back direction. Furthermore, each of the battery cells 32 is arranged such that the direction from the positive terminal to the negative terminal is opposite to that of two adjacent battery cells 32 in the front-to-back direction.

[0029] Metal lead plates 38a, 38b, 38c, 38d, 38e, and 38f are attached to the left and right sides of the cell cover 34. The lead plates 38a, 38b, 38c, 38d, 38e, and 38f are spaced apart to insulate them from each other. Lead plate 38a, shown in Figure 6, is connected to the negative terminal of the rearmost battery cell 32a. Lead plate 38b, shown in Figure 7, connects the positive terminal of battery cell 32a to the negative terminal of battery cell 32b, which is located in front of battery cell 32a. Lead plate 38c, shown in Figure 6, connects the positive terminal of battery cell 32b to the negative terminal of battery cell 32c, which is located in front of battery cell 32b. Lead plate 38d, shown in Figure 7, connects the positive terminal of battery cell 32c to the negative terminal of battery cell 32d, which is located in front of battery cell 32c. The lead plate 38e shown in Figure 6 connects the positive terminal of battery cell 32d to the negative terminal of battery cell 32e, which is located in front of battery cell 32d. The lead plate 38f shown in Figure 7 is connected to the positive terminal of battery cell 32e. The five battery cells 32 are electrically connected in series with each other via lead plates 38a, 38b, 38c, 38d, 38e, and 38f. As a result, the rated voltage of the battery pack 4 is 18[V].

[0030] As shown in Figure 6, the circuit board 36 is snap-fitted to the upper surface of the cell cover 34. Specifically, a plurality of claws 40 provided on the upper surface of the cell cover 34 engage with the circuit board 36. The circuit board 36 is arranged along planes perpendicular to each other in the vertical direction. A plurality of battery-side terminals 12 are provided on the upper surface of the circuit board 36.

[0031] As shown in Figure 8, the battery-side terminal 12 comprises a base portion 42 having a flat plate shape along the circuit board 36, two legs 44 extending downward from the front and rear ends of the base portion 42, two arms 46 extending upward from the left and right ends of the base portion 42, and two spring portions 48 extending from each of the two arms 46. The two legs 44 are fixed to the circuit board 36 by being inserted into through holes (not shown) formed in the circuit board 36. The two spring portions 48 are so-called leaf springs and are elastically deformable in the left-right direction. The two spring portions 48 comprise a first guide portion 50 whose distance from each other in the left-right direction decreases as it moves away from the base end (i.e., the arms 46), a second guide portion 52 whose distance from each other in the left-right direction decreases as it moves away from the tip, and a contact portion 54 located between the first guide portion 50 and the second guide portion 52.

[0032] When attaching the battery pack 4 to the charger 6, the device-side terminal 8 (see Figure 1) of the charger 6, which moves in the front-rear direction relative to the battery pack 4, passes between the two arm portions 46, pushes open the first guide portion 50 (or second guide portion 52), and is positioned between the contact portions 54. In this way, the device-side terminal 8 is clamped in the left-right direction by the battery-side terminal 12. Similarly, when attaching the battery pack 4 to the electric work implement 16, the device-side terminal 18 (see Figure 3) of the electric work implement 16, which moves in the front-rear direction relative to the battery pack 4, passes between the two arm portions 46, pushes open the first guide portion 50 (or second guide portion 52), and is positioned between the contact portions 54. In this way, the device-side terminal 18 is clamped in the left-right direction by the battery-side terminal 12.

[0033] As shown in Figure 9, the multiple battery-side terminals 12 include two battery-side positive terminals 56f, 56s used for discharging or charging, two battery-side negative terminals 58f, 58s used for discharging or charging, one battery-side discharge signal terminal 60 used for signal communication with the electric work machine 16, and two battery-side charge signal terminals 62f, 62s used for signal communication with the charger 6.

[0034] The battery-side positive terminals 56f and 56s are each positioned along a first virtual axis A1 parallel to the front-rear direction. Specifically, the battery-side positive terminal 56f is positioned such that the first virtual axis A1 is located between the contact portions 54 (see Figure 8) when the second guide portion 52 (see Figure 8) is facing rearward. The battery-side positive terminal 56s is positioned such that the first virtual axis A1 is located between the contact portions 54 (see Figure 8) when the second guide portion 52 (see Figure 8) is facing forward. The battery-side positive terminal 56s is positioned behind the battery-side positive terminal 56f.

[0035] The battery-side discharge signal terminal 60 is positioned along a second virtual axis A2 that is offset to the right by a first distance d1 with respect to the first virtual axis A1. Specifically, the battery-side discharge signal terminal 60 is positioned such that the second virtual axis A2 is located between the contact portions 54 (see Figure 8) with the second guide portion 52 (see Figure 8) facing forward. The first distance d1 is in the range of 6.0 mm to 8.0 mm, for example, 6.5 mm, 7.0 mm, or 7.5 mm.

[0036] The battery-side charging signal terminal 62f is positioned along a third virtual axis A3 that is offset to the right by a second distance d2 with respect to the second virtual axis A2. Specifically, the battery-side charging signal terminal 62f is positioned such that the third virtual axis A3 is located between the contact portions 54 (see Figure 8) with the second guide portion 52 (see Figure 8) facing forward. The second distance d2 is in the range of 17.0 mm to 19.0 mm, for example, 17.5 mm, 18.0 mm, or 18.5 mm.

[0037] The battery-side charging signal terminal 62s is positioned along a fourth virtual axis A4 that is offset to the right by a third distance d3 with respect to the third virtual axis A3. Specifically, the battery-side charging signal terminal 62s is positioned such that the fourth virtual axis A4 is located between the contact portions 54 (see Figure 8) with the second guide portion 52 (see Figure 8) facing forward. The third distance d3 is in the range of 6.0 mm to 8.0 mm, for example, 6.5 mm, 7.0 mm, or 7.5 mm.

[0038] The battery-side negative terminals 58f and 58s are each positioned along a fifth virtual axis A5 that is offset to the right by a fourth distance d4 with respect to the fourth virtual axis A4. Specifically, the battery-side negative terminal 58f is positioned such that the fifth virtual axis A5 is located between the contact portions 54 (see Figure 8) when the second guide portion 52 (see Figure 8) is facing rearward. The battery-side negative terminal 58s is positioned such that the fifth virtual axis A5 is located between the contact portions 54 (see Figure 8) when the second guide portion 52 (see Figure 8) is facing forward. The battery-side negative terminal 58s is positioned behind the battery-side negative terminal 58f. The fourth distance d4 is in the range of 6.0 mm to 8.0 mm, for example, 6.5 mm, 7.0 mm, or 7.5 mm.

[0039] In this embodiment, the first distance d1, the third distance d3, and the fourth distance d4 are set to equal values. The second distance d2 is set to a value greater than each of the first distance d1, the third distance d3, and the fourth distance d4. For example, the second distance d2 is set to a value greater than or equal to twice each of the first distance d1, the third distance d3, and the fourth distance d4. Alternatively, the ratio between the first distance d1, the second distance d2, the third distance d3, and the fourth distance d4 is set to a predetermined ratio (for example, 7:18:7:7).

[0040] In the front-to-back direction, the battery-side positive terminal 56s, the battery-side discharge signal terminal 60, and the battery-side negative terminal 58s are positioned at the same location relative to each other. Specifically, the rear end position of the battery-side positive terminal 56s, the rear end position of the battery-side discharge signal terminal 60, and the rear end position of the battery-side negative terminal 58s are positioned on a sixth virtual axis A6 parallel to the left-to-right direction. In the front-to-back direction, the battery-side charge signal terminal 62f and the battery-side charge signal terminal 62s are positioned at the same location relative to each other. Specifically, the rear end position of the battery-side charge signal terminal 62f and the rear end position of the battery-side charge signal terminal 62s are positioned on a seventh virtual axis A7 parallel to the left-to-right direction. The seventh virtual axis A7 is offset forward by a fifth distance d5 relative to the sixth virtual axis A6. That is, the rear end positions of the battery-side charging signal terminal 62f and the battery-side charging signal terminal 62s are offset forward by a fifth distance d5 relative to the battery-side positive terminal 56s, the battery-side discharge signal terminal 60, and the battery-side negative terminal 58s. The fifth distance d5 is in the range of 1.0 mm to 13.0 mm, for example, 3.0 mm.

[0041] As shown in Figure 7, on the lower surface of the circuit board 36, at the rear of the circuit board 36, there are three LEDs 64 and a switch 66. As shown in Figure 5, the rear wall of the lower case 28 is provided with a remaining charge indicator window 68 that transmits light from the three LEDs 64, and a button 70 for the user to turn the switch 66 on and off. The battery pack 4 can display the remaining charge by illuminating the three LEDs 64. The battery pack 4 also switches the display of the remaining charge on and off each time the switch 66 is turned on or off by operating the button 70. In addition, the bottom wall of the lower case 28 is provided with a plurality of support protrusions 72. The plurality of support protrusions 72 protrude upward from the bottom wall of the lower case 28. The upper ends of the plurality of support protrusions 72 each have a shape that conforms to the outer surface of the battery cell 32. The plurality of support protrusions 72 support the battery cell 32 by bringing their respective upper ends into contact with the outer surface of the battery cell 32.

[0042] As shown in Figure 10, the upper case 26 includes a slide rail 74, a terminal receiving section 76, and a hook 78.

[0043] The slide rail 74 slides into the charger 6's slide rail 216 (see Figure 1) or the electric work machine 16's slide rail 304 (see Figure 3) when attaching or detaching the battery pack 4 to the charger 6 or the electric work machine 16. The slide rail 74 comprises a first rail 80 located on the upper left of the upper case 26 and a second rail 82 located on the upper right of the upper case 26.

[0044] The terminal receiving section 76 is located on the upper part of the upper case 26, between the first rail 80 and the second rail 82. The terminal receiving section 76 comprises a front flat wall 84 that extends perpendicularly in the vertical direction at the front of the upper case 26, a rear flat wall 86 that extends perpendicularly in the vertical direction at the rear of the upper case 26, an upright wall 88 that extends perpendicularly in the front-rear direction and connects the front flat wall 84 and the rear flat wall 86, and a plurality of slits 90a, 90b, 90c, 90d, and 90e, each formed spanning the upright wall 88 and the front flat wall 84. The upper surface of the front flat wall 84 is flush with the upper surface of the first rail 80 and the upper surface of the second rail 82, respectively. The upper surface of the rear flat wall 86 is offset downward with respect to the upper surface of the front flat wall 84.

[0045] As shown in Figure 11, the upright wall 88 comprises a first flat wall section 92 extending to the right from the right side of the first rail 80, a first connecting section 94 extending forward from the right end of the first flat wall section 92, a second flat wall section 96 extending to the right from the front end of the first connecting section 94, a second connecting section 98 extending backward from the right end of the second flat wall section 96, and a third flat wall section 100 extending to the right from the rear end of the second connecting section 98 and connecting to the left side of the second rail 82. In the left-right direction, the first flat wall section 92 and the second flat wall section 96 are adjacent to each other, and the second flat wall section 96 and the third flat wall section 100 are adjacent to each other. In the front-rear direction, the positions of the first flat wall section 92 and the third flat wall section 100 are aligned with each other. Specifically, the rear surface of the first flat wall section 92 and the rear surface of the third flat wall section 100 are flush. In addition, the second flat wall section 96 is offset forward relative to both the first flat wall section 92 and the third flat wall section 100. Specifically, the rear surface of the second flat wall section 96 is offset forward relative to both the rear surface of the first flat wall section 92 and the rear surface of the third flat wall section 100.

[0046] Multiple slits 90a, 90b, 90c, 90d, and 90e are arranged from left to right in the order of slit 90a, slit 90b, slit 90c, slit 90d, and slit 90e. Slit 90a is positioned opposite the battery-side positive terminals 56f and 56s in the vertical direction. Slit 90a receives the device-side terminals 8 and 18 (i.e., the device-side positive terminal 256 shown in Figure 1 and the device-side positive terminal 356 shown in Figure 3) corresponding to the battery-side positive terminals 56f and 56s into the outer case 24. Slit 90b is positioned opposite the battery-side discharge signal terminal 60 in the vertical direction. Slit 90b receives the device-side terminal 18 (i.e., the device-side discharge signal terminal 360 shown in Figure 3) corresponding to the battery-side discharge signal terminal 60 into the outer case 24. Slit 90c is positioned opposite the battery-side charge signal terminal 62f in the vertical direction. Slit 90c receives the device-side terminal 8 (i.e., the device-side charging signal terminal 262f shown in Figure 1) corresponding to the battery-side charging signal terminal 62f into the outer case 24. Slit 90d is positioned opposite the battery-side charging signal terminal 62s in the vertical direction. Slit 90d receives the device-side terminal 8 (i.e., the device-side charging signal terminal 262s shown in Figure 1) corresponding to the battery-side charging signal terminal 62s into the outer case 24. Slit 90e is positioned opposite the battery-side negative terminals 58f and 58s in the vertical direction. Slit 90e receives the device-side terminals 8 and 18 (i.e., the device-side negative terminal 258 shown in Figure 1 and the device-side negative terminal 358 shown in Figure 3) corresponding to the battery-side negative terminals 58f and 58s into the outer case 24.

[0047] Slits 90a and 90b are formed spanning the first flat wall portion 92 and the front flat wall 84 of the upright wall 88. Slits 90c and 90d are formed spanning the second flat wall portion 96 and the front flat wall 84 of the upright wall 88. Slit 90e is formed spanning the third flat wall portion 100 and the front flat wall 84 of the upright wall 88.

[0048] As shown in Figure 12, the terminal receiving section 76 further includes a partition wall 102 that extends forward from the inner surface of the upright wall 88 and downward from the inner surface of the front flat wall 84. The partition wall 102 includes a first partition 104 that extends in the front-rear direction between slits 90a and 90b, a second partition 106 that passes to the right of slit 90b and extends along the front-rear direction, a third partition 108 that passes to the left of slit 90c and extends along the front-rear direction, a fourth partition 110 that passes between slits 90c and 90d and extends in the front-rear direction, and a fifth partition 112 that passes between slits 90d and 90e and extends in the front-rear direction.

[0049] As shown in Figure 10, the terminal receiving section 76 further comprises a plurality of guide recesses 114a, 114b, 114c, 114d, and 114e, and a plurality of fitting recesses 116a, 116b, and 116e. The guide recesses 114a, 114b, 114c, 114d, and 114e are formed by recessing the rear surface of the upright wall 88 forward around the slits 90a, 90b, 90c, 90d, and 90e, respectively. The left-right width of the guide recesses 114a, 114b, 114c, 114d, and 114e decreases as they extend forward. Guide recesses 114a, 114b, 114c, 114d, and 114e guide the equipment-side terminal 8 (or equipment-side terminal 18) moving from the rear to the front of the upright wall 88 to the slits 90a, 90b, 90c, 90d, and 90e. The fitting recesses 116a, 116b, and 116e are formed by recessing the upper surface of the front flat wall 84 downwards around the slits 90a, 90b, and 90e, respectively. The rear ends of the fitting recesses 116a, 116b, and 116e are connected to the upper ends of the guide recesses 114a, 114b, and 114e. The mating recesses 116a, 116b, and 116e respectively receive the mating protrusions 264a, 264b, and 264e (see Figure 1) that protrude from the terminal mounting surface 10 of the charger 6, and the mating protrusions 364a and 364e (see Figure 3) that protrude from the terminal mounting surface 20 of the electric work machine 16. Note that there are no recesses around the slits 90c and 90d.

[0050] As shown in Figure 11, the hook 78 is positioned on the front upper part of the upper case 26. The hook 78 includes a projection 118 and an operating part 120. The projection 118 protrudes to the outside of the outer case 24. The operating part 120 is exposed to the outside of the outer case 24 and is positioned so that it can be operated by the user even when the battery pack 4 is attached to the charger 6 or the electric work machine 16. The hook 78 is movable relative to the outer case 24. The hook 78 is biased outward toward the outer case 24 by a compression spring (not shown) attached to a projection 122 (see Figure 6) formed on the upper surface of the cell cover 34. When the operating part 120 or the projection 118 is pressed inward toward the outer case 24, the hook 78 moves inward toward the outer case 24 against the biasing force of the compression spring. When the battery pack 4 is attached to the charger 6 or the electric work implement 16, the protruding portion 118 engages with the engagement groove 218 of the charger 6 (see Figure 1) or the engagement groove 306 of the electric work implement 16 (see Figure 3) to fix the battery pack 4 to the charger 6 or the electric work implement 16. When removing the battery pack 4 from the charger 6 or the electric work implement 16, the operating portion 120 is pushed inward into the outer case 24, causing the protruding portion 118 to retract into the outer case 24. This releases the engagement between the protruding portion 118 and the engagement grooves 218 and 306. In this state, the battery pack 4 can be removed from the charger 6 or the electric work implement 16 by sliding it forward.

[0051] (Configuration of charger 6) Next, we will explain focusing on the charger 6. Here, we define the forward, backward, up, down, left, and right directions relative to the charger 6, separately from the forward, backward, up, down, left, and right directions relative to the battery pack 4. As shown in Figure 14, the charger 6 is usually used in a state where it is placed on a flat mounting surface P1. In this embodiment, the direction perpendicular to the mounting surface P1 and moving from the mounting surface P1 toward the charger 6 is defined as the upward direction of the charger 6. The direction perpendicular to the mounting surface P1 and moving from the charger 6 toward the mounting surface P1 is defined as the downward direction of the charger 6. Furthermore, the direction obtained by projecting the first direction D1 (see Figure 1) onto the mounting surface P is defined as the backward direction, and the opposite direction is defined as the forward direction. Furthermore, the direction obtained by projecting the third direction D3 (see Figure 1) onto the mounting surface P is defined as the left direction, and the opposite direction is defined as the right direction. Figures 13-17, which illustrate only the charger 6, show the forward, backward, up, down, left, and right directions relative to the charger 6.

[0052] As shown in Figure 13, the charger 6 comprises a circuit board 202 and a housing 204 that houses the circuit board 202. The housing 204 is divided into an upper housing 206 and a lower housing 208. The upper housing 206 and the lower housing 208 are fastened to each other by four screws 210. In the left wall of the housing 204, an opening 214 is defined between the upper housing 206 and the lower housing 208 for arranging a power cord 212 (see Figure 14).

[0053] The upper surface of the upper housing 206 is provided with a terminal mounting surface 10, a slide rail 216, an engagement groove 218, and a display unit 14. The terminal mounting surface 10, the slide rail 216, and the engagement groove 218 are located on the left side of the upper surface of the upper housing 206. The display unit 14 is located on the right side of the upper surface of the upper housing 206.

[0054] The slide rail 216 comprises a first rail 220 positioned to the right of the terminal mounting surface 10 and a second rail 222 positioned to the left of the terminal mounting surface 10. The first rail 220 slidably engages with the first rail 80 of the battery pack 4 (see Figure 10), thereby supporting the battery pack 4 so that it can slide in a first direction D1 and a fourth direction D4. The second rail 222 slidably engages with the second rail 82 of the battery pack 4 (see Figure 10), thereby supporting the battery pack 4 so that it can slide in a first direction D1 and a fourth direction D4.

[0055] The engagement groove 218 is located in front of the terminal mounting surface 10. The protruding portion 118 (see Figure 10) of the hook 78 provided on the battery pack 4 engages with the engagement groove 218.

[0056] As shown in Figure 15, the lower housing 208 has a protrusion 232 that projects upward from the upper end surface 230 of the lower housing 208. The upper housing 206 has a groove 236 that is recessed upward from the lower end surface 234 of the upper housing 206. The upper housing 206 and the lower housing 208 are positioned relative to each other by the protrusion 232 fitting into the groove 236.

[0057] The groove 236 comprises a bottom 238 facing downward, a first side 240 located inside the upper housing 206 as viewed from the bottom 238, and a second side 242 located outside the upper housing 206 as viewed from the bottom 238. The first side 240 connects the bottom 238 and the lower end surface 234 of the upper housing 206. The first side 240 slopes inward toward the upper housing 206 as it extends downward. The second side 242 connects the bottom 238 and the lower end surface 234 of the upper housing 206. The second side 242 extends substantially parallel to the vertical direction. The width of the groove 236 in the direction perpendicular to the vertical direction widens as it moves away from the bottom 238. The groove 236 is positioned such that the thickness t1 of the upper housing 206 located on the inside when viewed from the bottom 238 is approximately equal to the thickness t2 of the upper housing 206 located on the outside when viewed from the bottom 238.

[0058] The ridge 232 comprises a tip 244, a first side surface 246 located inside the lower housing 208 as viewed from the tip 244, and a second side surface 248 located outside the lower housing 208 as viewed from the tip 244. The first side surface 246 connects the tip 244 to the upper end surface 230 of the lower housing 208. The first side surface 246 slopes downward so as it extends inward toward the lower housing 208. The second side surface 248 comprises a base surface 250 extending from the upper end surface 230 of the lower housing 208, and a guide surface 252 extending from the tip 244 and connecting to the base surface 250. The base surface 250 extends substantially parallel to the vertical direction. The guide surface 252 slopes downward so as it extends outward toward the lower housing 208. The width of the ridge 232 in the direction perpendicular to the vertical direction widens as it moves away from the tip 244.

[0059] As shown in Figure 14, the terminal mounting surface 10 is inclined with respect to the front-to-back direction of the charger 6. The inclination angle of the terminal mounting surface 10 with respect to the front-to-back direction of the charger 6 is, for example, in the range of 3 to 30 degrees, when viewed from the right and counterclockwise is considered positive, and in this embodiment it is 8 degrees. The inclination angle of the terminal mounting surface 10 with respect to the front-to-back direction of the charger 6 can also be said to be the inclination angle in the first direction D1 with respect to the front direction of the charger 6, or the inclination angle in the fourth direction D4 with respect to the rear direction of the charger 6.

[0060] As shown in Figure 17, each of the device-side terminals 8 has a plate shape parallel to the first direction D1 and the second direction D2, and is integrated into the upper housing 206 by insert molding. The device-side terminals 8 include a device-side positive terminal 256 used for charging the battery pack 4 from the charger 6, a device-side negative terminal 258 used for charging the battery pack 4 from the charger 6, and two device-side charging signal terminals 262f and 262s used for signal communication between the charger 6 and the battery pack 4.

[0061] Each of the two device-side charging signal terminals 262f and 262s is positioned in space SL to the left of a virtual plane P2 that bisects the space between the device-side positive terminal 256 and the device-side negative terminal 258 in the left-right direction. The positions of the ends of the device-side positive terminal 256 in the fourth direction D4 and the positions of the ends of the device-side negative terminal 258 in the fourth direction D4 are aligned with each other and are positioned on the eighth virtual axis A8 which is parallel to the left-right direction. The positions of the ends of the two device-side charging signal terminals 262f and 262s in the fourth direction D4 are aligned with each other and are positioned on the ninth virtual axis A9 which is parallel to the left-right direction. The ninth virtual axis A9 is offset by a sixth distance d6 in the fourth direction D4 relative to the eighth virtual axis A8. That is, the positions of the ends of the fourth direction D4 of each of the two device-side charging signal terminals 262f and 262s are offset by a sixth distance d6 in the fourth direction D4 with respect to the positions of the ends of the fourth direction D4 of the device-side positive terminal 256 and the end of the fourth direction D4 of the device-side negative terminal 258. The sixth distance d6 is in the range of 1.0 mm to 13.0 mm, for example, 3.0 mm. In this embodiment, the sixth distance d6 is set to the same value as the fifth distance d5.

[0062] The upper housing 206 is provided with a plurality of mating protrusions 264a, 264b, and 264e that protrude upward from the terminal mounting surface 10. The mating protrusion 264a is positioned to contact the positive terminal 256 on the equipment side. The mating protrusion 264b is positioned not to contact any of the terminals 8 on the equipment side. The mating protrusion 264e is positioned to contact the negative terminal 258 on the equipment side. The mating protrusions 264a and 264b are located in the space SR on the right side when viewed from the virtual plane P2. The mating protrusion 264e is located in the space SL on the left side when viewed from the virtual plane P2. The mating protrusions 264a, 264b, and 264e respectively fit into the mating recesses 116a, 116b, and 116e of the battery pack 4 when the battery pack 4 is attached to the charger 6, thereby partially closing the slits 90a, 90b, and 90e.

[0063] As shown in Figure 14, the circuit board 202 is sandwiched between an upper support projection 224 protruding from the inner surface of the upper housing 206 and a lower support projection 226 protruding from the inner surface of the lower housing 208. The circuit board 202 is arranged along a plane perpendicular to the vertical direction. The circuit board 202 is also provided with multiple connection terminals 228 corresponding to multiple device-side terminals 8.

[0064] As shown in Figure 16, the connector 228 comprises a fitting portion 402 that fits into a rectangular through hole (not shown) formed in the circuit board 202 (see Figure 14), a flat plate portion 404 extending horizontally from the upper end of the fitting portion 402, a pair of left and right spring portions 406 extending downward from the lower end of the fitting portion 402, and a protrusion 408 formed spanning the outer surface of the fitting portion 402 and the outer surface of the spring portion 406. The connector 228 is attached to the circuit board 202 such that the circuit board 202 is positioned between the flat plate portion 404 and the protrusion 408. The flat plate portion 404 abuts against the upper surface of the circuit board 202, preventing the connector 228 from moving downward relative to the circuit board 202. The protrusion 408 abuts against the lower surface of the circuit board 202, preventing the connector 228 from moving upward relative to the circuit board 202. The spring portion 406 is a so-called leaf spring and is elastically deformable in the left-right direction. The spring portion 406 includes a first guide portion 410 whose distance from each other in the left-right direction decreases as it moves away from the base end (i.e., the fitting portion 402), a second guide portion 412 whose distance from each other in the left-right direction decreases as it moves away from the tip, and a contact portion 414 located between the first guide portion 410 and the second guide portion 412.

[0065] As shown in Figure 14, the device-side terminal 8 is inserted into the connection terminal 228 so as to spread the first guide portion 410 (see Figure 16) and is sandwiched between the contact portions 414 (see Figure 16). The device-side terminal 8 is electrically connected to the circuit board 202 via the connection terminal 228.

[0066] As shown in Figures 18 and 19, the battery pack 4 is attached to the charger 6 by sliding it in a first direction D1 relative to the charger 6. When the battery pack 4 is attached to the charger 6, each of the device-side terminals 8 of the charger 6 moves in a fourth direction D4 relative to the outer case 24 of the battery pack 4. In this case, the device-side positive terminal 256 passes through the slit 90a and enters the interior of the outer case 24, and is finally clamped by the battery-side positive terminal 56s, thereby electrically connecting to the battery-side positive terminal 56s. The device-side negative terminal 258 passes through the slit 90e and enters the interior of the outer case 24, and is finally clamped by the battery-side negative terminal 58s, thereby electrically connecting to the battery-side negative terminal 58s. The device-side charging signal terminal 262f passes through the slit 90c and enters the interior of the outer case 24, and is finally clamped by the battery-side charging signal terminal 62f, thereby electrically connecting to the battery-side charging signal terminal 62f. The device-side charging signal terminal 262s passes through the slit 90d and enters the interior of the outer case 24, and is finally sandwiched between the battery-side charging signal terminal 62s, thereby electrically connecting to the battery-side charging signal terminal 62s.

[0067] As shown in Figure 18, during the process of attaching the battery pack 4 to the charger 6, each of the battery-side terminals 12 of the battery pack 4 begins to make contact with each of the device-side terminals 8 of the charger 6 almost simultaneously. At the timing when the battery-side terminals 12 begin to make contact with the device-side terminals 8, the resistance force felt by the user sliding the battery pack 4 (specifically, the force resisting the sliding of the battery pack 4) increases. If the timing at which each of the battery-side terminals 12 begins to make contact with each of the device-side terminals 8 were different, the resistance force would increase in multiple stages while the user was attaching the battery pack 4 to the charger 6. As a result, the user would not be able to slide the battery pack 4 smoothly, which could cause frustration. In contrast, in this embodiment, since the timing at which each of the battery-side terminals 12 begins to make contact with each of the device-side terminals 8 is almost simultaneous, the multi-stage increase in resistance force while the user is attaching the battery pack 4 to the charger 6 is suppressed. This allows the user to slide the battery pack 4 smoothly, thus preventing the user from feeling frustrated.

[0068] As shown in Figure 20, the battery pack 4 includes a voltage detection circuit 132 for detecting the voltage of each battery cell 32, a current detection circuit 134 for detecting the current flowing through each battery cell 32, a temperature sensor 136 for detecting the temperature of the battery cell 32, a battery-side control circuit 138 for controlling each part of the battery pack 4, a first battery-side power line 140 for electrically connecting the battery cell 32 to the battery-side positive terminals 56f and 56s, a second battery-side power line 146 for electrically connecting the battery cell 32 to the battery-side negative terminals 58f and 58s, a first battery-side signal line 148 for electrically connecting the battery-side control circuit 138 to the battery-side charging signal terminal 62f, a second battery-side signal line 150 for electrically connecting the battery-side control circuit 138 to the battery-side charging signal terminal 62s, and a third battery-side signal line 152 for electrically connecting the battery-side control circuit 138 to the battery-side discharge signal terminal 60. The voltage detection circuit 132, current detection circuit 134, temperature sensor 136, and battery-side control circuit 138 are each mounted on the circuit board 36 (see Figure 6). The values ​​detected by the voltage detection circuit 132, the current detection circuit 134, and the temperature sensor 136 are input to the battery-side control circuit 138, respectively.

[0069] The charger 6 comprises a power supply circuit 272 electrically connected to an external power source (e.g., commercial power) via a power cord 212 (see Figure 14), an equipment-side control circuit 274 that controls various parts of the charger 6, two switch circuits 276 and 278 (e.g., FETs) that turn on and off in response to instructions from the equipment-side control circuit 274, a first equipment-side power line 280 electrically connecting the power supply circuit 272 and the equipment-side positive terminal 256, a second equipment-side power line 282 electrically connecting the power supply circuit 272 and the equipment-side negative terminal 258, a first equipment-side signal line 284 electrically connecting the equipment-side control circuit 274 and the equipment-side charging signal terminal 262f, and a second equipment-side signal line 286 electrically connecting the equipment-side control circuit 274 and the equipment-side charging signal terminal 262s. The two switch circuits 276 and 278 are each provided on the first equipment-side power line 280 and selectively connect and disconnect between the power supply circuit 272 and the equipment-side positive terminal 256. The power supply circuit 272, the equipment-side control circuit 274, and the two switch circuits 276 and 278 are each mounted on the circuit board 202 (see Figure 13).

[0070] The battery-side control circuit 138 outputs a first charge prohibition signal to the first battery-side signal line 148 to prohibit charging of the battery cell 32 when the detected value of the voltage detection circuit 132 (i.e., the voltage of the battery cell 32) is equal to or greater than a first threshold (e.g., 4.0[V]). On the other hand, the battery-side control circuit 138 outputs a first charge permit signal to the first battery-side signal line 148 to permit charging of the battery cell 32 when the detected value of the voltage detection circuit 132 is less than the first threshold. The first charge prohibition signal or the first charge permit signal output to the first battery-side signal line 148 is input to the device-side control circuit 274 via the battery-side charge signal terminal 62f, the device-side charge signal terminal 262f, and the first device-side signal line 284. When the first charge prohibition signal is input to the device-side control circuit 274, the device-side control circuit 274 switches the switch circuit 276 to off. When the first charge-allowing signal is input to the device-side control circuit 274, the device-side control circuit 274 switches the switch circuit 276 to ON. The first threshold value is a value that fluctuates depending on the temperature detected by the temperature sensor 136 (i.e., the temperature of the battery cell 32). For example, if the temperature detected by the temperature sensor 136 is high (e.g., above 20 degrees), the first threshold value will be a large value (e.g., 4.2[V]). If the temperature detected by the temperature sensor 136 is low (e.g., below 0 degrees), the first threshold value will be a small value (e.g., 1.0[V]).

[0071] The battery-side control circuit 138 outputs a second charge prohibition signal to the second battery-side signal line 150 to prohibit charging of the battery cell 32 when the detected value of the voltage detection circuit 132 is equal to or greater than a second threshold (for example, 4.3[V]). On the other hand, the battery-side control circuit 138 outputs a second charge permit signal to the second battery-side signal line 150 to permit charging of the battery cell 32 when the detected value of the voltage detection circuit 132 is less than the second threshold. The second charge prohibition signal or the second charge permit signal output to the second battery-side signal line 150 is input to the device-side control circuit 274 via the battery-side charge signal terminal 62s, the device-side charge signal terminal 262s, and the second device-side signal line 286. When the second charge prohibition signal is input to the device-side control circuit 274, the device-side control circuit 274 switches the switch circuit 278 to off. When the second charge allow signal is input to the device-side control circuit 274, the device-side control circuit 274 switches the switch circuit 278 to ON. The second threshold value is independent of the temperature detected by the temperature sensor 136.

[0072] When both switch circuits 276 and 278 are on, charging from the power supply circuit 272 to the battery cell 32 is permitted, and charging of the battery cell 32 from the power supply circuit 272 takes place. When at least one of the two switch circuits 276 and 278 is off, charging from the power supply circuit 272 to the battery cell 32 is prohibited, and charging of the battery cell 32 from the power supply circuit 272 does not take place.

[0073] (Configuration of the electric work machine 16) As shown in Figure 3, the electric work machine 16 is equipped with a battery mounting section 302 for attaching the battery pack 4. The battery mounting section 302 comprises a slide rail 304, an engagement groove 306, and a terminal block 308 provided with a plurality of equipment-side terminals 18. The slide rail 304 slidably engages with the slide rail 304 of the battery pack 4 (see Figure 10), similar to the slide rail 216 of the charger 6 (see Figure 1). The protruding portion 118 (see Figure 10) of the hook 78 provided on the battery pack 4 engages with the engagement groove 306, similar to the engagement groove 218 of the charger 6 (see Figure 1).

[0074] The terminal block 308 comprises a terminal mounting surface 20 on which the equipment-side terminals 18 protrude, and a housing section 310 for housing a part of the equipment-side terminals 18 and wiring (not shown) for connecting to the equipment-side terminals 18. The terminal mounting surface 20 is located in the fourth direction D4 when viewed from the housing section 310.

[0075] Each of the multiple device-side terminals 18 has a plate shape parallel to the first direction D1 and the second direction D2 in the portion exposed to the outside of the terminal block 308. The multiple device-side terminals 18 include a device-side positive terminal 356 used for discharge from the battery pack 4 to the electric work machine 16, a device-side negative terminal 358 used for discharge from the battery pack 4 to the electric work machine 16, and a device-side discharge signal terminal 360 used for signal communication between the battery pack 4 and the electric work machine 16.

[0076] The terminal block 308 further comprises a plurality of mating protrusions 364a and 364e that project upward from the terminal mounting surface 20. The mating protrusions 364a are positioned to contact the positive terminal 356 on the equipment side. The mating protrusions 364e are positioned to contact the negative terminal 358 on the equipment side. When the battery pack 4 is attached to the electric work machine 16, the mating protrusions 364a and 364e respectively engage with the mating recesses 116a and 116e of the battery pack 4, thereby partially closing the slits 90a and 90e.

[0077] As shown in Figure 21, the battery pack 4 is attached to the electric work implement 16 by sliding it in a first direction D1 relative to the electric work implement 16. When the battery pack 4 is attached to the electric work implement 16, each of the equipment-side terminals 18 of the electric work implement 16 moves in a fourth direction D4 relative to the outer case 24 of the battery pack 4. In this case, the equipment-side positive terminal 356 passes through the slit 90a and enters the interior of the outer case 24, and is finally held between the battery-side positive terminals 56f and 56s, and is electrically connected to the battery-side positive terminals 56f and 56s. The equipment-side negative terminal 358 passes through the slit 90e and enters the interior of the outer case 24, and is finally held between the battery-side negative terminals 58f and 58s, and is electrically connected to the battery-side negative terminals 58f and 58s. The device-side discharge signal terminal 360 passes through the slit 90b and enters the interior of the outer case 24, and is finally clamped by the battery-side discharge signal terminal 60, thereby electrically connecting to the battery-side discharge signal terminal 60.

[0078] When the battery pack 4 is attached to the battery mounting section 302, the end face 312 of the housing section 310 of the terminal block 308, facing the fourth direction D4, faces the upright wall 88 of the battery pack 4. The housing section 310 has a raised portion 314 that rises from the end face 312 in the fourth direction D4 at a position facing the second flat wall section 96 of the upright wall 88. If the second flat wall section 96 were flush with the first flat wall section 92 or the third flat wall section 100, as in the embodiment, the raised portion 314 would interfere with (i.e., come into contact with) the upright wall 88 when attempting to attach the battery pack 4 to the electric work machine 16. Therefore, the battery pack 4 cannot be attached to the electric work machine 16. In contrast, in this embodiment, the portion of the upright wall 88 that contacts the second flat wall section 96 is recessed in the fourth direction D4, thereby preventing the raised portion 314 from interfering with the upright wall 88. Therefore, the battery pack 4 can be attached to the electric work implement 16.

[0079] As shown in Figure 22, the electric work machine 16 includes an electric unit 322 (e.g., an electric motor) that operates by power supply, an equipment-side control circuit 324 that controls each part of the electric work machine 16, a switch circuit 326 (e.g., an FET) that turns on and off in response to instructions from the equipment-side control circuit 324, a first equipment-side power line 328 that electrically connects the electric unit 322 and the equipment-side positive terminal 356, a second equipment-side power supply 330 that electrically connects the electric unit 322 and the equipment-side negative terminal 358, and an equipment-side signal line 332 that electrically connects the equipment-side control circuit 324 and the equipment-side discharge signal terminal 360. The switch circuit 326 is provided on the first equipment-side power line 328 and selectively connects and disconnects the electric unit 322 and the equipment-side positive terminal 356.

[0080] The battery-side control circuit 138 outputs a discharge-permit signal to the third battery-side signal line 152 to permit discharge from the battery cell 32 when predetermined discharge-permit conditions are met. Discharge-permit conditions include, for example, that the detected value of the voltage detection circuit 132 (i.e., the voltage of the battery cell 32) is greater than or equal to a predetermined value, that the detected value of the current detection circuit 134 (i.e., the current flowing through each of the battery cells 32) is less than or equal to a predetermined value, and / or that the detected temperature of the temperature sensor 136 is less than or equal to a predetermined value. On the other hand, the battery-side control circuit 138 outputs a discharge-prohibition signal to the third battery-side signal line 152 to prohibit discharge from the battery cell 32 when predetermined discharge-prohibition conditions are met. Discharge-prohibition conditions include, for example, that the detected value of the voltage detection circuit 132 (i.e., the voltage of the battery cell 32) is less than a predetermined value, that the detected value of the current detection circuit 134 (i.e., the current flowing through each of the battery cells 32) is greater than a predetermined value, and / or that the detected temperature of the temperature sensor 136 is greater than a predetermined value.

[0081] The discharge-permit signal or discharge-prohibition signal output to the third battery-side signal line 152 is input to the device-side control circuit 324 via the battery-side discharge signal terminal 60, the device-side discharge signal terminal 360, and the device-side signal line 332. When a discharge-permit signal is input to the device-side control circuit 324, the device-side control circuit 324 switches the switch circuit 326 to ON. When the switch circuit 326 is ON, discharge from the battery cell 32 to the motor unit 322 is permitted, and the operation of the motor unit 322 is permitted. When a discharge-prohibition signal is input to the device-side control circuit 324, the device-side control circuit 324 switches the switch circuit 326 to OFF. When the switch circuit 326 is OFF, discharge from the battery cell 32 to the motor unit 322 is prohibited, and the operation of the motor unit 322 is prohibited.

[0082] (modified version) (See Figures 9 and 11) The arrangement of the battery-side terminals 12 in the battery pack 4 may be changed. For example, the positions of the battery-side positive terminals 56f and 56s and the battery-side discharge signal terminal 60 may be swapped. In this case, slit 90a may accept the device-side terminal corresponding to the battery-side discharge signal terminal 60, and slit 90b may accept the device-side terminal corresponding to the battery-side positive terminals 56f and 56s. Alternatively, the positions of the battery-side negative terminals 58f and 58s and the battery-side charge signal terminal 62s may be swapped. In this case, slit 90d may accept the device-side terminal corresponding to the battery-side negative terminals 58f and 58s, and slit 90e may accept the device-side terminal corresponding to the battery-side charge signal terminal 62s. Alternatively, the battery-side discharge signal terminal 60 may be aligned with the battery-side charge signal terminal 62f (or battery-side charge signal terminal 62s) in the front-to-back direction (i.e., in the first direction D1 and the fourth direction D4). In this case, one slit may accept a device-side terminal corresponding to the battery-side discharge signal terminal 60 and a device-side terminal corresponding to the battery-side charge signal terminal 62f (or battery-side charge signal terminal 62s). Alternatively, the battery-side charge signal terminals 62f and 62s may be aligned in the front-to-back direction of the battery pack 4 (i.e., the first direction D1 and the fourth direction D4). In this case, one slit may accept two device-side terminals corresponding to each of the battery-side charge signal terminals 62f and 62s.

[0083] In accordance with the change in the arrangement of the battery-side terminal 12 described above, the arrangements of the device-side terminal 8 and device-side terminal 18 may also be changed.

[0084] (See Figure 20) The battery pack 4 does not need to have one of the battery-side charging signal terminals 62f or 62s. In this case, there may be only one communication path between the battery pack 4 and the charger 6.

[0085] (See Figure 9) The rear end positions of the battery-side charging signal terminals 62f and 62s may be located on the sixth virtual axis A6 instead of the seventh virtual axis A7. That is, the rear end positions of the battery-side charging signal terminals 62f and 62s may be aligned with the rear end position of the battery-side positive terminal 56s, the rear end position of the battery-side discharge signal terminal 60, and the rear end position of the battery-side negative terminal 58s.

[0086] (See Figures 11 and 17) In addition to the fitting recesses 116a, 116b, and 116e, the battery pack 4 may further include recesses formed by recessing the upper surface of the front flat wall 84 downward around the slit 90c, and / or recesses formed by recessing the upper surface of the front flat wall 84 downward around the slit 90d. In this case, the charger 6 may further include protrusions that fit into the above-mentioned recesses added to the battery pack 4. In other words, the terminal mounting surface 10 of the charger 6 may be provided with protrusions that contact the device-side charging signal terminals 262f and 262s.

[0087] (See Figures 11 and 17) The charger 6 does not have to have at least one of the mating protrusions 264a, 264b, and 264e. In this case, the battery pack 4 does not have to have at least one of the mating recesses 116a, 116b, and 116e that correspond to at least one of the mating protrusions 264a, 264b, and 264e.

[0088] (See Figure 9) The second distance d2 (i.e., the distance between the battery-side discharge signal terminal 60 and the battery-side charge signal terminal 62f) may be equal to the first distance d1, the third distance d3, and the fourth distance d4 (i.e., the distances between the other terminals).

[0089] (See Figure 17) The arrangement of the device-side terminals 8 in the charger 6 may be changed. For example, each of the two device-side charging signal terminals 262f and 262s may be placed in the space SR to the right when viewed from a virtual plane P2 that bisects the space between the device-side positive terminal 256 and the device-side negative terminal 258 in the left-right direction. Also, the positions of the ends of each of the two device-side charging signal terminals 262f and 262s in the fourth direction D4 may be placed on the eighth virtual axis A8 instead of the ninth virtual axis A9. That is, the positions of the ends of each of the two device-side charging signal terminals 262f and 262s in the fourth direction D4 may be aligned with the positions of the ends of the device-side positive terminal 256 in the fourth direction D4 and the positions of the ends of the device-side negative terminal 258 in the fourth direction D4. Alternatively, the positions of the ends of the second device-side charging signal terminals 262f and 262s in the fourth direction D4 may be offset in the first direction D1 with respect to the position of the end of the second device-side positive terminal 256 in the fourth direction D4 and the position of the end of the second device-side negative terminal 258 in the fourth direction D4, respectively.

[0090] (See Figure 17) The charger 6 may have three or more device-side charging signal terminals. Two of the three or more device-side charging signal terminals may be located on one side of the space demarcated by the virtual plane P2 (i.e., one of spaces SL and SR).

[0091] In accordance with the changes in the arrangement of the device-side terminal 8 described above, the arrangements of the battery-side terminal 12 and the device-side terminal 18 may also be changed.

[0092] (Features of the example) The charger 6 of this embodiment is a charger 6 to which a battery pack 4 equipped with battery-side terminals 12 can be attached and detached. The charger 6 comprises a housing 204 to which the battery pack 4 is attached by slidingly receiving the battery pack 4 along a predetermined first direction D1, and a plurality of device-side terminals 8, each having a plate shape parallel to the first direction D1 and parallel to a second direction D2 from the battery pack 4 toward the housing 204, and engaging with the battery-side terminals 12 of the battery pack 4 attached to the housing 204. The plurality of device-side terminals 8 comprises two charging terminals 256, 258 for charging the battery pack 4 from the charger 6, and two signal terminals 262f, 262s for signal communication between the charger 6 and the battery pack 4. The two charging terminals 256, 258 are spaced apart from each other in a third direction D3 perpendicular to the first direction D1 and the second direction D2. Each of the two signal terminals 262f and 262s is located on one side SL of the space partitioned by a virtual plane P2 that bisects the space between the two charging terminals 256 and 258 in the third direction D3.

[0093] Chargers with multiple device-side terminals arranged at approximately equal intervals, such as the one disclosed in Patent Document 1, are commonly available. In the above configuration, two signal terminals 262f and 262s are located near the device-side negative terminal 258 (an example of one charging terminal). The device-side positive terminal 256 (an example of the other charging terminal) is located at a distance from the other device-side terminals 8 (i.e., the device-side negative terminal 258 and the two signal terminals 262f and 262s). As a result, the layout of the device-side terminals 8 is clearly different from the layout of the device-side terminals in commonly available chargers (i.e., chargers with multiple device-side terminals arranged at approximately equal intervals). This makes it possible to determine from the difference in appearance that the charger 6 of this application and commonly available chargers are not compatible. Therefore, the above configuration makes it possible to realize a charger 6 that can be easily determined to be compatible with other chargers.

[0094] In one or more embodiments, the positions (A8) of the ends (A8) of the respective ends (A9) of the fourth direction D4 of the two charging terminals 256, 258 are aligned in the fourth direction D4 opposite to the first direction D1. The positions (A9) of the respective ends (A9) of the fourth direction D4 of the two signal terminals 262f, 262s are offset to one of the first direction D1 and the fourth direction D4 with respect to the positions (A8) of the respective ends (A8) of the fourth direction D4 of the two charging terminals 256, 258.

[0095] With the above configuration, the positions of the two signal terminals 262f and 262s are biased towards the first direction D1 (or fourth direction D4) relative to the positions of the two charging terminals 256 and 258. Therefore, it becomes easier for the user to distinguish between the signal terminals 262f and 262s and the charging terminals 256 and 258.

[0096] In one or more embodiments, the position (A9) of the end of each of the two signal terminals 262f, 262s in the fourth direction D4 is offset in the fourth direction D4 with respect to the position (A8) of the end of each of the two charging terminals 256, 258 in the fourth direction D4.

[0097] With the above configuration, the positions of the two signal terminals 262f and 262s are biased towards the fourth direction D4 relative to the positions of the two charging terminals 256 and 258. Therefore, it becomes easier for the user to distinguish between the signal terminals 262f and 262s and the charging terminals 256 and 258.

[0098] In one or more embodiments, the housing 204 includes a terminal mounting surface 10 facing a battery pack 4 attached to the housing 204, and a plurality of device-side terminals 8, and a plurality of protrusions 264a, 264b, 264e projecting from the terminal mounting surface 10 toward the battery pack 4. Each of the two charging terminals 256, 258 protrudes toward the battery pack 4 from the terminal mounting surface 10 where the protrusions 264a, 264b, 264e are provided. Each of the two signal terminals 262f, 262s protrudes toward the battery pack 4 from the terminal mounting surface 10 where the protrusions 264a, 264b, 264e are not provided.

[0099] With the above configuration, terminals protruding from the locations on the terminal mounting surface 10 where protrusions 264a, 264b, and 264e are provided can be identified as charging terminals 256 and 258, while terminals protruding from locations on the terminal mounting surface 10 where protrusions 264a, 264b, and 264e are not provided can be identified as signal terminals 262f and 262s. Therefore, it becomes easier for the user to distinguish between signal terminals 262f and 262s and charging terminals 256 and 258.

[0100] In one or more embodiments, the housing 204 includes a terminal mounting surface 10 facing a battery pack 4 attached to the housing 204, and a plurality of device-side terminals 8, and a plurality of protrusions 264a, 264b, 264e projecting from the terminal mounting surface 10 toward the battery pack 4. Each of the two signal terminals 262f, 262s protrudes toward the battery pack 4 from a location on the terminal mounting surface 10 where the protrusions 264a, 264b, 264e are not provided. The protrusions 264b (an example of at least one protrusion) are positioned so as not to be in contact with the plurality of device-side terminals 8 on the other side SR of the space demarcated by the virtual plane P2.

[0101] With the above configuration, a battery pack 4 having recesses 116a, 116b, and 116e corresponding to the protrusions 264a, 264b, and 264e can be attached to the charger 6. On the other hand, even if one attempts to attach a battery pack (not shown) that does not have recesses 116a, 116b, and 116e corresponding to the protrusions 264a, 264b, and 264e to the charger 6, the protrusions 264a, 264b, and 264e will interfere with the battery pack, making it impossible to attach the battery pack to the charger 6. This prevents unintended battery packs from being attached to the charger 6.

[0102] Another charger 6 disclosed herein is a charger 6 to which a battery pack 4 having battery-side terminals 12 can be attached and detached. The charger 6 comprises a housing 204 to which the battery pack 4 is attached by slidingly receiving the battery pack 4 along a predetermined first direction D1, and a plurality of device-side terminals 8, each having a plate shape parallel to the first direction D1 and parallel to a second direction D2 from the battery pack 4 toward the housing 204, and engaging with the battery-side terminals 12 of the battery pack 4 attached to the housing 204. The plurality of device-side terminals 8 comprises two charging terminals 256, 258 for charging the battery pack 4 from the charger 6, and two signal terminals 262f, 262s for signal communication between the charger 6 and the battery pack 4. The housing 204 comprises a terminal mounting surface 10 facing the battery pack 4 attached to the housing 204 and provided with the plurality of device-side terminals 8, and a plurality of protrusions 264a, 264b, 264e projecting from the terminal mounting surface 10 toward the battery pack 4. Each of the two charging terminals 256 and 258 protrudes toward the battery pack 4 from the terminal mounting surface 10 where the protrusions 264a, 264b, and 264e are provided. Each of the two signal terminals 262f and 262s protrudes toward the battery pack 4 from the terminal mounting surface 10 where the protrusions 264a, 264b, and 264e are not provided.

[0103] With the above configuration, terminals protruding from the locations on the terminal mounting surface 10 where protrusions 264a, 264b, and 264e are provided can be identified as charging terminals 256 and 258, while terminals protruding from locations on the terminal mounting surface 10 where protrusions 264a, 264b, and 264e are not provided can be identified as signal terminals 262f and 262s. Therefore, it becomes easier for the user to distinguish between signal terminals 262f and 262s and charging terminals 256 and 258.

[0104] Another charger 6 disclosed herein is a charger 6 to which a battery pack 4 having battery-side terminals 12 can be attached and detached. The charger 6 comprises a housing 204 to which the battery pack 4 is attached by slidingly receiving the battery pack 4 along a predetermined first direction D1, and a plurality of device-side terminals 8, each having a plate shape parallel to the first direction D1 and parallel to a second direction D2 from the battery pack 4 toward the housing 204, and engaging with the battery-side terminals 12 of the battery pack 4 attached to the housing 204. The plurality of device-side terminals 8 comprises two charging terminals 256, 258 for charging the battery pack 4 from the charger 6, and two signal terminals 262f, 262s for signal communication between the charger 6 and the battery pack 4. The housing 204 comprises a terminal mounting surface 10 facing the battery pack 4 attached to the housing 204 and provided with the plurality of device-side terminals 8, and a plurality of protrusions 264a, 264b, 264e projecting from the terminal mounting surface 10 toward the battery pack 4. Each of the two signal terminals 262f and 262s protrudes toward the battery pack 4 from a location on the terminal mounting surface 10 where no protrusions 264a, 264b, or 264e are provided. The protrusions 264b (an example of at least one protrusion) are positioned so as not to come into contact with any of the device-side terminals 8.

[0105] With the above configuration, a battery pack 4 having recesses 116a, 116b, and 116e corresponding to the protrusions 264a, 264b, and 264e can be attached to the charger 6. On the other hand, even if one attempts to attach a battery pack (not shown) that does not have recesses 116a, 116b, and 116e corresponding to the protrusions 264a, 264b, and 264e to the charger 6, the protrusions 264a, 264b, and 264e will interfere with the battery pack, making it impossible to attach the battery pack to the charger 6. This prevents unintended battery packs from being attached to the charger 6. [Explanation of Symbols]

[0106] 2: Charging system, 4: Battery pack, 6: Charger, 8: Device-side terminal, 10: Terminal mounting surface, 12: Battery-side terminal, 14: Display unit, 16: Electric work machine, 18: Device-side terminal, 20: Terminal mounting surface, 22: Battery module, 24: Outer case, 26: Upper case, 28: Lower case, 30: Screw, 32a: Battery cell, 32b: Battery cell, 32c: Battery cell, 32d: Battery cell, 32e: Battery cell, 34: Cell cover, 36: Circuit board, 38a: Lead plate, 38b: Lead plate, 38c: Lead plate, 38d: Lead plate, 38e: Lead plate, 38f: Lead plate, 40: 42: Claw, 44: Base, 46: Leg, 48: Spring, 50: First guide, 52: Second guide, 54: Contact point, 56f: Battery side positive terminal, 56s: Battery side positive terminal, 58f: Battery side negative terminal, 58s: Battery side negative terminal, 60: Battery side discharge signal terminal, 62f: Battery side charge signal terminal, 62s: Battery side charge signal terminal, 64: LED, 66: Switch, 68: Battery level indicator window, 70: Button, 72: Support projection, 74: Slide rail, 76: Terminal receiving part, 78: Hook, 80: First rail, 82: Second rail, 84: Front flat wall, 86: Rear flat wall, 88: Vertical wall , 90a: Slit, 90b: Slit, 90c: Slit, 90d: Slit, 90e: Slit, 92: First flat wall section, 94: First connection section, 96: Second flat wall section, 98: Second connection section, 100: Third flat wall section, 102: Partition wall, 104: First partition, 106: Second partition, 108: Third partition, 110: Fourth partition, 112: Fifth partition, 114a: Guide recess, 114b: Guide recess, 114c: Guide recess, 114d: Guide recess, 114e: Guide recess, 116a: Fitting recess, 116b: Fitting recess, 116e: Fitting recess, 118: Protrusion, 120: Operation 122: Protrusion, 132: Voltage detection circuit, 134: Current detection circuit, 136: Temperature sensor, 138: Battery side control circuit, 140: First battery side power line, 146: Second battery side power line, 148: First battery side signal line, 150: Second battery side signal line, 152: Third battery side signal line, 202: Circuit board, 204: Housing, 206: Upper housing, 208: Lower housing, 210: Screw, 212: Power cord, 214: Opening, 216: Slide rail, 218: Engagement groove, 220: First rail, 222: Second rail, 224: Upper support protrusion, 226: Lower support protrusion,228: Connection terminal, 230: Upper end face, 232: Protrusion, 234: Lower end face, 236: Groove, 238: Bottom, 240: First side, 242: Second side, 244: Tip, 246: First side, 248: Second side, 250: Base surface, 252: Guide surface, 256: Device side positive terminal, 258: Device side negative terminal, 262f: Device side charging signal terminal, 262s: Device side charging signal terminal, 264a: Mating projection, 264b: Mating projection, 264e: Mating projection, 272: Power supply circuit, 274: Device side control circuit, 276: Switch circuit, 278: Switch circuit, 280: First device side power line, 282: Second device side power supply, 284: First device 286: Second device side signal line, 302: Battery mounting section, 304: Slide rail, 306: Engagement groove, 308: Terminal block, 310: Housing section, 312: End face, 314: Raised section, 322: Motor section, 324: Device side control circuit, 326: Switch circuit, 328: First device side power line, 330: Second device side power supply, 332: Device side signal line, 356: Device side positive terminal, 358: Device side negative terminal, 360: Device side discharge signal terminal, 364a: Mating projection, 364e: Mating projection, 402: Mating section, 404: Flat plate section, 406: Spring section, 408: Projection section, 410: First guide section, 412: Second guide section, 414: Contact section,

Claims

1. A charger that allows the attachment and detachment of a battery pack equipped with battery-side terminals, The housing to which the battery pack is attached is provided by slidably receiving the battery pack along a predetermined first direction, Each has a plate shape parallel to the first direction and parallel to the second direction from the battery pack toward the housing, and comprises a plurality of device-side terminals that engage with the battery-side terminals of the battery pack attached to the housing, The aforementioned multiple device-side terminals are, Two charging terminals for charging the battery pack from the charger, It is equipped with two signal terminals for signal communication between the charger and the battery pack, The two charging terminals are spaced apart from each other in a third direction perpendicular to the first and second directions. A charger in which each of the two signal terminals is located on one side of a space partitioned by a virtual plane that bisects the space between the two charging terminals in the third direction.

2. In the fourth direction opposite to the first direction, the positions of the ends of each of the two charging terminals in the fourth direction are aligned. The charger according to claim 1, wherein the position of the end of each of the two signal terminals in the fourth direction is offset to one of the first and fourth directions with respect to the position of the end of each of the two charging terminals in the fourth direction.

3. The charger according to claim 2, wherein the position of the end of each of the two signal terminals in the fourth direction is offset in the fourth direction with respect to the position of the end of each of the two charging terminals in the fourth direction.

4. The aforementioned housing is The aforementioned plurality of device-side terminals are provided, and the terminal mounting surface facing the battery pack attached to the housing, It is equipped with a plurality of protrusions that extend from the terminal mounting surface toward the battery pack, Each of the two charging terminals protrudes toward the battery pack from the location on the terminal mounting surface where the protrusion is provided. The charger according to claim 1, wherein each of the two signal terminals protrudes toward the battery pack from a portion of the terminal mounting surface where the protrusion is not provided.

5. The aforementioned housing is The aforementioned plurality of device-side terminals are provided, and the terminal mounting surface facing the battery pack attached to the housing, It is equipped with a plurality of protrusions that extend from the terminal mounting surface toward the battery pack, Each of the two signal terminals protrudes toward the battery pack from a portion of the terminal mounting surface where the protrusion is not provided. The charger according to claim 1, wherein at least one of the protrusions is arranged so as not to come into contact with the plurality of device-side terminals on the other side of the space partitioned by the virtual plane.

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