Battery pack

Abstract

To arrange a plurality of connection terminals at precise positions on a case while reducing part cost and manufacturing cost as a simple structure.SOLUTION: A battery pack includes a battery unit 10 in which a battery cell 1 is arranged at a fixed position with a cell holder 2, a circuit board 3 arranged at a fixed position of the battery unit 10, and a case 4 containing the circuit board 3 and the battery unit 10. The circuit board 3 has a plurality of connection terminals 5 fixed to its surface for connection to an external device. The case 4 includes a surface plate 41 having a terminal window 44 opened for exposing the connection terminals 5 to the outside. The circuit board 3 is connected to a fixed position of the cell holder 2, sandwiched between the battery unit 10 and the surface plate 41 having the terminal window 44 opened, and placed in a fixed position in the case 4, and the connection terminal 5 is exposed through the terminal window 44.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery pack in which a connection terminal is exposed through a terminal window in a case. [Background technology]

[0002] Battery packs with connection terminals provided in terminal windows in the case are often used in portable devices such as cameras, and the battery packs can be conveniently used by being set in a predetermined position in an external device such as a portable device, and the multiple connection terminals can be electrically connected to the terminals of the device. When the battery pack is set in a fixed position in the case, it is required that the connection terminals can be electrically connected reliably and stably to multiple terminals such as power terminals and signal terminals of the external device for a long period of time without causing poor contact. To achieve this, conventional battery packs have multiple connection terminals fixed to a terminal holder, and the terminal holder is built into the case. In order to position the multiple connection terminals in a fixed position, the terminal holder is connected to a circuit board or a battery holder, and is positioned in a fixed position in the case via the holder (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-138483 A Summary of the Invention [Problem to be solved by the invention]

[0004] Battery packs in which multiple connection terminals are fixed to a terminal holder, the terminal holder is connected to a circuit board or a battery holder, and each connection terminal is disposed inside a case have the disadvantage that it is difficult to position all of the connection terminals in accurate positions, and the structure and number of parts are increased, resulting in high part costs and manufacturing costs.

[0005] The present invention was developed with the aim of eliminating the above-mentioned drawbacks of conventional battery packs, and an important object of the present invention is to provide a battery pack that has a simple structure, reduces component costs and manufacturing costs, and allows multiple connection terminals to be positioned accurately in the case. [Means for solving the problem]

[0006] A battery pack according to one embodiment of the present invention comprises a battery unit in which battery cells are arranged in fixed positions by cell holders, a circuit board arranged in fixed positions in the battery unit, and a case housing the circuit board and the battery unit. The circuit board has a plurality of connection terminals fixed to its surface for connection to an external device. The case has a surface plate with a terminal window that exposes the connection terminals to the outside. The circuit board is connected to the cell holder in a fixed position, and is sandwiched between the battery unit and the surface plate with the terminal window, and is arranged in a fixed position within the case, exposing the connection terminals in the terminal window. Effect of the Invention

[0007] The above battery pack has a simple structure, reducing component costs and manufacturing costs, while allowing multiple connection terminals to be positioned accurately on the case. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a battery pack according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of the battery pack shown in FIG. [Diagram 3] 3 is an exploded perspective view of the battery pack shown in FIG. 2, seen from below. [Figure 4] 4 is a cross-sectional view of the battery pack shown in FIG. 1 taken along line IV-IV. [Diagram 5] FIG. [Figure 6] 4 is a cross-sectional view showing a state in which the battery unit is being inserted into the box-shaped case. FIG. [Figure 7]4 is a cross-sectional view showing a state in which the battery unit is being inserted into the box-shaped case. FIG. [Figure 8] 11 is an enlarged sectional perspective view showing a locked state between a first case locking portion and a first holder locking portion. FIG. [Figure 9] 13 is an enlarged sectional perspective view showing a locked state between a second case locking portion and a second holder locking portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A battery pack according to one embodiment of the present invention comprises a battery unit in which battery cells are arranged in fixed positions using cell holders, a circuit board arranged in a fixed position on the battery unit, and a case housing the circuit board and the battery unit, the circuit board having a plurality of connection terminals fixed to its surface for connection to an external device, and the case having a surface plate with a terminal window through which the connection terminals are exposed to the outside, the circuit board being connected to the cell holder in a fixed position and sandwiched between the battery unit and the surface plate with the terminal window so as to be arranged in a fixed position within the case, with the connection terminals exposed in the terminal window.

[0010] In the battery pack described above, a circuit board is placed in a fixed position on a cell holder that holds battery cells in fixed positions, and multiple connection terminals are fixed directly to the circuit board, eliminating the need for a terminal holder to fix multiple connection terminals as in conventional battery packs. Also, because multiple connection terminals are fixed directly to the circuit board, wiring such as lead wires connecting the connection terminals to the circuit board can be omitted. By omitting the terminal holder, component costs can be reduced, and there is no need to connect the terminal holder to the circuit board or battery holder, simplifying the manufacturing process and reducing manufacturing costs.

[0011] Furthermore, battery packs require protection circuits to control the charging and discharging of battery cells, and therefore require a circuit board on which to mount this protection circuit. However, this circuit board has a larger outer shape than a terminal holder which has only connection terminals mounted thereon, as it mounts various electronic components. Furthermore, since the circuit board is positioned in a fixed position within the case via a cell holder or the like, the connection terminals which are fixed directly to the circuit board are positioned in fixed positions within the case by the circuit board.

[0012] Furthermore, in the battery pack described above, the circuit board is sandwiched and positioned between the battery unit, in which the battery cells are positioned in fixed positions by cell holders, and the surface plate of the case, which has a terminal window, so that the circuit board with the connection terminals can be closest to the inner surface of the surface plate with the terminal window. The circuit board is closest to the inner surface of the surface plate with the terminal window, and the connection terminals fixed to the circuit board are closest to the inner surface of the surface plate and positioned in the optimal position for the terminal window. This structure prevents the connection terminals from shifting relative to the terminal window of the surface plate and the connection terminals, and holds the connection terminals in a fixed position on the case with high precision, and in particular prevents the connection terminals from shifting relative to the surface plate of the case, which has the terminal window, thereby achieving the advantage of effectively preventing problems such as poor contact. Furthermore, the structure in which the circuit board is sandwiched and held in a fixed position between the battery unit and the surface plate also achieves the advantage of effectively preventing poor contact over long periods of use.

[0013] The battery pack is set in the external device, and the connection terminal comes into contact with an elastically deformable terminal, i.e., an elastic terminal, provided on the external device to establish an electrical connection. The elastic terminal is elastically deformed and pressed against the surface of the connection terminal to establish an electrical connection. The elastic terminal is pressed against the connection terminal of the battery pack with a certain contact pressure to establish a normal electrical connection, so a reduction in the contact pressure can cause a contact failure. Misalignment of the connection terminal of the battery pack, particularly misalignment of the connection terminal in the pressing direction of the elastic terminal, can reduce the contact pressure and cause a contact failure.

[0014] In the above battery pack, the connection terminals are fixed to the circuit board, and the circuit board is sandwiched between the battery unit and a surface plate with a terminal window to position the connection terminals in a fixed position, so that even when the battery pack is set in an external device and the connection terminals are elastically pressed by an elastic terminal, the circuit board to which the connection terminals are fixed is prevented from shifting in position. This is because the circuit board is sandwiched between the surface plate and the battery unit, and the battery unit prevents the circuit board from shifting in position. When set in an external device, the connection terminals are elastically pressed by the elastic terminal of the external device, so that the connection terminals do not shift in position, and changes in contact pressure with the elastic terminal of the external device are suppressed. Therefore, even when used for a long period of time, the connection terminals are reliably and stably electrically connected to the elastic terminal of the external device, realizing the feature of preventing poor contact.

[0015] In a battery pack according to another embodiment of the present invention, the outer peripheral edge of the circuit board and the cell holder are connected by an interlocking structure in which an interlocking convex portion is guided into an interlocking concave portion, thereby connecting the circuit board to a fixed position on the cell holder.

[0016] In the above-described battery pack, the circuit board is connected in a fixed position to the cell holder by a fitting structure, so that the connection terminals of the circuit board, which is sandwiched and positioned in a fixed position between the battery unit and the surface plate of the case, can be positioned in the terminal window of the case with greater precision.

[0017] In a battery pack according to another embodiment of the present invention, the circuit board has an engaging recess on its outer peripheral edge, and the cell holder has an engaging protrusion that is guided into the engaging recess to position the circuit board in a fixed position, and the circuit board is connected to the cell holder in a fixed position by an engaging structure in which the engaging protrusion is guided into the engaging recess.

[0018] In the above battery pack, by providing a mating recess on the outer peripheral edge of the circuit board, the mating recess can be easily formed, and the circuit board can be securely connected to a fixed position in the cell holder through a mating structure with a mating protrusion provided on the cell holder.

[0019] In a battery pack according to another embodiment of the present invention, a circuit board is provided with fitting recesses on both sides of a terminal area in which connection terminals are provided.

[0020] The circuit board of the battery pack described above has mating recesses on both sides of the terminal area, so that the circuit board can be connected to the cell holder without misalignment, and this has the advantage of preventing misalignment of the connection terminals.

[0021] In a battery pack according to another embodiment of the present invention, a circuit board has connection terminals on its front surface, and a cell holder is integrally formed with a plurality of support ribs that support the rear surface of the circuit board.

[0022] In the above-described battery pack, the back surface of the circuit board is supported by multiple support ribs of the cell holder, thereby preventing misalignment of the circuit board, particularly in the direction in which it is pressed against the terminals of an external device, and thus having the advantage of more effectively preventing poor contact.

[0023] In a battery pack according to another embodiment of the present invention, the cell holder and the case are connected by an engagement structure between a holder engagement portion provided on the cell holder and a case engagement portion provided on the case.

[0024] The above battery pack has an engaging structure for connecting the cell holder and the case, and therefore has the advantage that it can be easily assembled by engaging the holder engaging parts with the case engaging parts to connect the battery unit and the case.

[0025] A battery pack according to another embodiment of the present invention comprises a box-shaped case formed into a box shape with a peripheral wall consisting of side walls and end walls around a surface plate, and a lid case closing the opening of the box-shaped case, the box-shaped case having a terminal window opened in the surface plate, a cell holder connected to the box-shaped case by an engagement structure, a circuit board sandwiched between the cell holder and the box-shaped case, and a connection terminal positioned at the exposed position of the terminal window.

[0026] In a battery pack according to another embodiment of the present invention, the box-shaped case has case locking portions protruding from the inner surfaces of a pair of side walls, and the cell holder has a holder locking portion that is locked to the case locking portions.

[0027] A battery pack according to another embodiment of the present invention includes a pair of side walls of a box-shaped case, the pair of side walls including a vertical side wall connected to the surface plate in a vertical posture and an inclined side wall connected to the surface plate in an inclined posture. The case locking portion includes a first case locking portion provided on the inner surface of the vertical side wall and a second case locking portion provided on the inner surface of the inclined side wall, and the first case locking portion protrudes higher than the second case locking portion.

[0028] In the above battery pack, one holder locking portion of the cell holder is locked to the first case locking portion of the vertical side wall, the battery unit is inserted into the box-shaped case while tilting, and the other holder locking portion of the cell holder is locked to the second case locking portion of the inclined side wall, so that the battery unit can be smoothly inserted into the box-shaped case and connected to a fixed position with a locking structure.

[0029] In a battery pack according to another embodiment of the present invention, a terminal window is opened at a side edge where the vertical side wall is connected to the surface plate.

[0030] In the above battery pack, the box-shaped case is provided with a vertical side wall in a vertical posture connected to a side edge on the terminal window side opened in the surface plate and an inclined side wall in an inclined posture on the opposite side edge, so that the connection strength between the side wall on the side where the terminal window is opened and the surface plate can be increased, the displacement of the circuit board locked here can be reduced, and the connection terminals can be accurately positioned with respect to the terminal window.

[0031] In a battery pack according to another embodiment of the present invention, the side wall of the box-shaped case has elasticity such that the holder locking portion can move to a locking position beyond the case locking portion, and the side wall is elastically deformed to dispose the holder locking portion at the locking position of the case locking portion.

[0032] In the above battery pack, the side wall of the box-shaped case is elastically deformed, so that the battery unit can be easily inserted into the box-shaped case, and the battery unit can be connected to a fixed position with a locking structure in the box-shaped case.

[0033] In another embodiment of the battery pack of the present invention, the side walls of the box-shaped case include a vertical side wall connected to the surface plate at a right angle and an inclined side wall connected to the surface plate at an obtuse angle, and the inclined side wall has a curved shape with its central portion protruding outward.

[0034] The above battery pack has the advantage that the battery unit can be easily and smoothly inserted into the box-shaped case, and the battery unit can be connected to the box-shaped case by an engagement structure.

[0035] In a battery pack according to another embodiment of the present invention, the case locking portion has an upwardly sloping surface toward the insertion direction of the holder locking portion, and the holder locking portion moves along the sloping surface to be guided to the locking position of the case locking portion.

[0036] In the battery pack described above, the holder locking portion can slide along the inclined surface to smoothly move to the locking position of the case locking portion, so that the battery unit can be smoothly inserted into the box-shaped case and connected with the locking structure.

[0037] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members. Furthermore, the embodiments shown below are specific examples of the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention. Furthermore, the contents described in one embodiment or example can be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0038] (Embodiment 1) A battery pack according to a first embodiment of the present invention is shown in Figures 1 to 4. Figure 1 is a perspective view of the battery pack, Figure 2 is an exploded perspective view of the battery pack in Figure 1, Figure 3 is an exploded perspective view of the battery pack in Figure 2 seen from below, and Figure 4 is a vertical cross-sectional view taken along line IV-IV of the battery pack in Figure 1. The battery pack 100 shown in these figures comprises a battery unit 10 in which multiple battery cells 1 are connected to a cell holder 2, a circuit board 3 connected to a fixed position of the battery unit 10, and a case 4 in which the circuit board 3 and the battery unit 10 are housed.

[0039] (Battery unit 10) Battery unit 10 arranges multiple battery cells 1 in fixed positions in a parallel posture using cell holders 2. Battery cells 1 are cylindrical batteries, and preferably non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries can be used, but the present invention does not limit battery cells 1 to cylindrical batteries or non-aqueous electrolyte secondary batteries, and all secondary batteries currently in use or to be developed in the future can be used.

[0040] (Cell holder 2) The cell holder 2 is produced by molding insulating plastic. The cell holder 2 shown in Figures 2 to 5 has two rows of grooves 21 on the front side to guide the two cylindrical batteries. End plates 22 are provided on both ends of the grooves 21 to position the end faces of the cylindrical batteries on the inside. The back side of the cell holder 2 has multiple support ribs 23 to support the planar circuit board 3, a mating protrusion 24 to connect the circuit board 3 in a fixed position, and a locking portion 6 that is connected to the case 4 in a fixed position with a locking structure.

[0041] Groove 21 is formed into a shape that fits the outer periphery of the cylindrical battery, and the cylindrical battery is guided into the groove to position it in place. The cylindrical battery is guided into groove 21 and can be joined to cell holder 2 with double-sided adhesive tape to prevent it from shifting out of position. End plate 22 has through holes 22a that expose the positive and negative electrodes on both ends of the cylindrical battery, and lead plates 11 are welded to the electrodes exposed in through holes 22a, electrically connecting battery cells 1 via lead plates 11. The battery unit 10 shown in the figures connects two battery cells 1 in series with lead plates 11 to make the output voltage twice that of battery cell 1, but the battery cells 1 can also be connected in parallel.

[0042] Since the groove 21 is molded into a shape that conforms to the cylinder and has an uneven surface, a plurality of support ribs 23 are provided at predetermined intervals in the axial direction of the cylinder on the surface facing the circuit board 3. The support ribs 23 protrude perpendicularly to the surface facing the circuit board 3 and are arranged vertically to the front surface of the circuit board 3 to support the circuit board 3 from the back side. The contact surface of each support rib 23 with the circuit board 3 is arranged on the same plane as the back side of the circuit board 3 so that the planar circuit board 3 can be supported from the back side. The cell holder 2 in FIG. 5 has two rows of support ribs 23 that support both sides of the circuit board 3 (top and bottom of the circuit board 3 in FIG. 5) and are arranged on both sides of the groove 21. Furthermore, the cell holder 2 in FIG. 5 has a step portion 25 that fits the lower edge of the circuit board 3 in the figure. The step portion 25 prevents the circuit board 3 from being displaced downward in the figure. The cell holder 2 in the figures has a support section 27 that is disposed on the same plane as the circuit board 3 by extending downward the center of the opposing wall 26 that forms the step section 25. The support section 27 of the cell holder 2 can be bonded to the inner surface of the case 4 with double-sided adhesive tape 12 so as not to shift position.

[0043] Furthermore, the cell holder 2 is provided with a fitting protrusion 24 that is guided into a fitting recess 34 provided on the outer periphery of the circuit board 3 in order to prevent the circuit board 3 from being displaced vertically and horizontally. The cell holder 2 is provided with the fitting protrusion 24 on the back side that faces the circuit board 3. The fitting protrusion 24 is guided into the fitting recess 34 of the circuit board 3 to place the circuit board 3 in a fixed position on the cell holder 2. The circuit board 3 in Figures 2, 3, and 5 is provided with fitting recesses 34 on both sides of the terminal area 31 in which the connection terminals 5 are provided, and therefore the fitting protrusions 24 that are guided into the fitting recesses 34 are provided protruding toward the circuit board 3. The fitting protrusions 24 that protrude toward the circuit board 3 are guided into the fitting recesses 34 of the circuit board 3 and do not protrude from the surface of the circuit board 3. The mating protrusions 24 that do not protrude from the surface of the circuit board 3 do not prevent the connection terminals 5 from coming into close contact with the inner surface of the case 4 when the circuit board 3 is sandwiched between the case 4 and the battery unit 10. The mating protrusions 24 that do not protrude from the surface of the circuit board 3 can sandwich the circuit board 3 between the pair of mating protrusions 24, connecting the circuit board 3 in a state in which it is difficult to remove it. The cell holder 2 in Figs. 1 and 2 guides the mating protrusions 24 into the mating recesses 34 provided on both sides of the terminal area 31 of the circuit board 3, so that it is possible to more effectively prevent the mating protrusions 24 from being displaced from the connection terminals 5 provided on the circuit board 3. The circuit board 3 in the figures has mating recesses 34 on both side edges and on the top and bottom edges, so that the cell holder 2 has multiple mating protrusions 24 that are inserted into each mating recess 34.

[0044] (Circuit board 3) The circuit board 3 has electronic components (not shown) for realizing the protection circuit of the battery cell 1 mounted on an insulating substrate. As the insulating substrate, for example, an epoxy resin substrate reinforced with glass fiber can be used. The protection circuit includes a circuit for detecting overcharging and overdischarging of the battery and controlling the current, a circuit for detecting overcurrent of the battery and interrupting the current, a circuit for detecting the temperature of the battery and interrupting the current when the temperature becomes abnormal, and the like. The circuit board 3 has electronic components arranged on the surface facing the cell holder 2, and is planar without mounting electronic components on the surface facing the inner surface of the surface plate 41 of the case 4. This circuit board 3 is in close contact with the inner surface of the surface plate 41 of the case 4, and the connection terminals 5 of the circuit board 3 can be in close contact with the inner surface of the surface plate 41. However, the circuit board 3 can also have electronic components mounted on the surface facing the inner surface of the surface plate, and recesses for guiding the electronic components can be formed on the inner surface of the surface plate so that the connection terminals can be in close contact with the inner surface of the surface plate.

[0045] The circuit board 3 is smaller than the outer shape of the cell holder 2 and also smaller than the outer shape of the surface plate 41 of the case 4, and has an outer shape that can be in close contact with the inner surface of the surface plate 41. Since the circuit board 3 needs to mount a large number of electronic components for realizing the protection circuit and further bond a plurality of connection terminals 5 to the surface, the circuit boards 3 in FIGS. 1 and 2 are in the shape of a rectangle smaller than the width (W) and length (L) of the inner surface of the surface plate 41 and are in close contact with the inner surface of the surface plate 41. The circuit board 3 can have its outer shape enlarged so that the connection terminals 5 can be stably in close contact with the inner surface of the surface plate 41. By setting the width (H) and length (D) of the circuit board 3 to, for example, 1 / 2 or more, preferably 3 / 4 or more of the inner shape of the surface plate 41, a plurality of connection terminals 5 can be stably and surely in close contact with the inner surface of the surface plate 41.

[0046] The connection terminal 5 is a metal plate, and is fixed to the surface of the circuit board 3, facing the inner surface of the surface plate 41 of the case 4. The connection terminal 5 is preferably gold-plated to reduce contact resistance due to a metal oxide film on the surface. However, a metal plate such as nickel without plating can also be used for the connection terminal 5. The connection terminal 5 in the figure has positive and negative power terminals 5a and two signal terminals 5b. The connection terminal 5 has the power terminal 5a and the signal terminal 5b in a rectangular shape, and the positive and negative power terminals 5a are wider than the signal terminals 5b to allow a large current to flow. The positive and negative power terminals 5a are arranged apart, and the signal terminal 5b is arranged between them. The power terminals 5a and the signal terminals 5b are arranged in a straight line in the terminal area 31 of the circuit board 3, and are fixed in an insulated state with a predetermined gap between them. The circuit board 3 in Figures 2 to 5 has the terminal area 31 on the outer periphery (the upper edge in the figures). On both sides of the terminal area 31, mating recesses 34 are provided to guide the mating protrusions 24 of the cell holder 2 and prevent misalignment.

[0047] The connection terminals 5 are fixed in place by being soldered to the conductive parts of the circuit board 3 and electrically connected thereto. The connection terminals 5 are provided with connection leads (not shown) protruding from the outer periphery in order to be soldered to the conductive parts of the circuit board 3. The connection leads are inserted into through holes (not shown) in the circuit board 3 and are connected by soldering to the conductive parts provided on the back surface. The connection terminals 5 are fixed in place on the circuit board 3 via the connection leads that penetrate the circuit board 3 and are soldered to the conductive parts. The connection terminals 5 are arranged in place on the case 4 via the circuit board 3 that is sandwiched between the front plate 41 of the case 4 and the cell holder 2 and arranged in place.

[0048] The circuit board 3 has mating recesses 34 on its outer periphery to connect to the cell holder 2 at a fixed position. The mating protrusions 24 of the cell holder 2 are guided into the mating recesses 34 to connect to the cell holder 2 at a fixed position. The circuit board 3 in Figs. 2, 3, and 5 has mating recesses 34 on its upper and lower edges to prevent vertical misalignment, and mating recesses 34 on both left and right side edges to prevent horizontal misalignment. The mating recesses 34 on the upper edge are located on both sides of the terminal area 31, and two mating recesses 34 are provided on the lower edge and both side edges. The mating protrusions 24 on the cell holder 2 are guided into each mating recess 34 to place the circuit board 3 at a fixed position. The mating convex portions 24 guided by the upper and lower edges of the circuit board 3 can elastically pinch the circuit board 3 from above and below, connecting it in a state in which it is difficult to come off, and the mating convex portions 24 guided by the left and right mating recesses 34 can also elastically pinch the circuit board 3 from the left and right, connecting it in a state in which it is difficult to come off.

[0049] (Case 4) The battery pack 100 in Figs. 1 to 4 is composed of a box-shaped case 4A and a lid case 4B which are molded separately. The box-shaped case 4A is molded from plastic into a rectangular box shape with a peripheral wall consisting of a side wall 42 and an end wall 43 around the periphery of a surface plate 41. The lid case 4B is molded into a box shape with a peripheral wall lower than that of the box-shaped case 4A, and the box-shaped case 4A and the lid case 4B are connected by the peripheral wall, and the opening of the box-shaped case 4A is closed by the lid case 4B. The case 4 is assembled by inserting the battery unit 10 into the box-shaped case 4A and connecting the lid case 4B to the box-shaped case 4A. The box-shaped case 4A has a pair of side walls 42 composed of a vertical side wall 42A connected at a right angle to the surface plate 41 and an inclined side wall 42B connected to the surface plate 41 at an angle. In the case 4 shown in the figures, the peripheral walls of the box-shaped case 4A and the lid case 4B are connected. The box-shaped case 4A and the lid case 4B can be connected with a locking structure, a fitting structure, ultrasonic welding, or adhesive bonding. The case 4 shown in the figures has connecting hooks 48 on the peripheral wall of the box-shaped case 4A, and the lid case 4B has hooks 49 for hooking the connecting hooks 48, and they are connected with a locking structure.

[0050] The box-shaped case 4A has a terminal window 44 opened in the surface plate 41 at a position where the connection terminals 5 are exposed. The inner shape of the terminal window 44 is smaller than the outer shape of the connection terminals 5, in other words, the outer shape of the connection terminals 5 is larger than the inner shape of the terminal window 44, and the connection terminals 5 are exposed throughout the entire inside of the terminal window 44. The battery pack 100 has the circuit board 3 sandwiched between the surface plate 41 of the box-shaped case 4A and the cell holder 2, and the circuit board 3 is positioned in a fixed position so as not to shift, and each connection terminal 5 is exposed in the terminal window 44. The box-shaped case 4A and the cell holder 2 are connected via a locking portion 6 so that the surface plate 41 and the cell holder 2 of the case 4 hold the circuit board 3 in a sandwiched state and position the connection terminals 5 in a fixed position.

[0051] (Lock structure between case 4 and cell holder 2) The box-shaped case 4A and the cell holder 2 are connected by a locking structure, the battery unit 10 is placed in a fixed position in the box-shaped case 4A, and the circuit board 3 is sandwiched between the surface plate 41 of the box-shaped case 4A and the cell holder 2, so that the circuit board 3 is in close contact with the inner surface of the surface plate 41. The locking structure shown in Figures 2 to 4 includes a case locking portion 7 that protrudes from the inside of a pair of side walls 42 of the box-shaped case 4A, and a holder locking portion 8 that is provided on the cell holder 2, and the battery unit 10 is connected to the case 4 by locking the holder locking portion 8 to the case locking portion 7. As shown in the cross-sectional view of Figure 4, the case locking portion 7 has an inclined surface 7c that slopes upward toward the insertion direction of the holder locking portion 8. When the battery unit 10 is inserted into the box-shaped case 4A, this case locking portion 7 allows the holder locking portion 8 of the cell holder 2 to slide along the inclined surface 7c, smoothly guiding it to the locking position of the case locking portion 7.

[0052] (Case locking part 7) 2 and 3 has a U-shape in plan view, with upwardly sloping ribs 7a connected to both sides of a main body wall 7b. The sloping ribs 7a are provided in an orientation that extends in the insertion direction of the battery unit 10, and are molded as an integral structure with the side wall 42. The sloping ribs 7a of this case locking portion 7 also act as ribs that reinforce the main body wall 7b, connecting the main body wall 7b to the side wall 42 with sufficient strength.

[0053] The box-shaped case 4A has a vertical side wall 42A connected to the surface plate 41 at a right angle, and an inclined side wall 42B connected to the surface plate 41 at an obtuse angle, and the inclined side wall 42B has a curved shape that protrudes outward at the center. As shown in the exploded cross-sectional view of FIG. 6, the curved shape of the inclined side wall 42B is shaped to follow the path of movement of the bottom surface of the battery unit 10 when the battery unit 10 is rotated in the direction indicated by arrow A with the upper part of the battery unit 10 inserted into the corner between the surface plate 41 and the vertical side wall 42A of the box-shaped case 4A. As shown in FIG. 6, the box-shaped case 4A of this shape allows the battery unit 10 to be smoothly inserted and the holder locking portion 8 of the cell holder 2 to move to the locking position of the case locking portion 7. The vertical side wall 42A has a first case locking portion 7A that protrudes on the inner surface, and the inclined side wall 42B has a second case locking portion 7B that protrudes on the inner surface. The first case locking portion 7A is higher than the second case locking portion 7B, in other words, the second case locking portion 7B is lower than the first case locking portion 7A.

[0054] The box-shaped case 4A shown in the figures has a vertical side wall 42A connected to one side edge of a surface plate 41 on the side where a terminal window 44 is opened, and an inclined side wall 42B connected to the opposite side edge. In other words, the vertical side wall 42A of the box-shaped case 4A is connected to the side edge on the side where the end of the battery unit 10 is inserted, where the terminal area 31 of the connection terminal 5 arranged opposite the terminal window 44 is arranged. This structure has the feature that the holder locking portion 8 on the upper end of the cell holder 2 on the side where the connection terminal 5 is arranged can be locked with the first case locking portion 7A provided on the vertical side wall 42A to reliably support the cell holder 2.

[0055] Furthermore, the side walls 42 of the box-shaped case 4A are molded from plastic to a thickness that allows elastic deformation. When the battery unit 10 is set in a fixed position inside the box-shaped case 4A, the box-shaped case 4A elastically deforms in a state in which the holder locking parts 8 of the cell holders 2 move past the case locking parts 7 into the locking position as shown in Figure 7. This means that the battery unit 10 can be smoothly inserted into the box-shaped case 4A while still providing a more secure locking structure, i.e., the holder locking parts 8 penetrate deeply into the case locking parts 7 for a deep locking effect, preventing the battery unit 10 from coming loose.

[0056] (Holder locking part 8) The cell holder 2 is provided with a first holder locking portion 8A that is locked to the first case locking portion 7A and a second holder locking portion 8B that is locked to the second case locking portion 7B, at locking positions of the case locking portion 7. In Figures 2 and 3, the cell holder 2 is provided with the first holder locking portion 8A on its upper surface and the second holder locking portion 8B on its lower surface. As shown in Figures 4, 5, and 8, the first holder locking portion 8A is plate-shaped with a locking surface that is locked in surface contact with the main body wall 7b of the first case locking portion 7A, and both side edges are connected to the support ribs 23. 3 and 9, the second holder locking portion 8B is plate-shaped with a locking surface that is locked in surface contact with the main body wall 7b of the second case locking portion 7B, with one side edge connected to the support portion 27 connected to the groove portion 21 and the other side edge connected to the end plate portion 22. The holder locking portion 8 having this shape is connected to the cell holder 2 as an integral structure with sufficient strength via the support rib 23, the support portion 27, or the end plate portion 22, so that the holder locking portion 8 can be connected to the cell holder 2 with sufficient strength. A battery pack 100 in which the case locking portion 7 of the side wall 42 is connected to the side wall 42 with high strength via the inclined rib 7a and the holder locking portion 8 is connected to the cell holder 2 with high strength via the support rib 23, the end plate portion 22, etc. can increase the connection strength between the cell holder 2 and the case 4. This battery pack 100 has the advantage that the circuit board 3 is firmly sandwiched between the surface plate 41 and the cell holder 2, and the connection terminals 5 can be reliably brought into close contact with the inner surface of the surface plate 41.

[0057] As shown in Figures 6 and 7, the box-shaped case 4A and battery unit 10 described above have the advantage that the corner of the battery unit 10 where the first holder locking portion 8A is provided is inserted into the box-shaped case 4A first, and the battery unit 10 is inserted while tilting it into the box-shaped case 4A until the first holder locking portion 8A locks into the locking position of the first case locking portion 7A, allowing the battery unit 10 to be inserted smoothly into the box-shaped case 4A while being securely locked in a state that is unlikely to come loose.

[0058] The above battery pack 100 can be assembled in the following steps. 2 and 3, the circuit board 3 is connected to a fixed position of the cell holder 2 using a fitting structure, and the connection terminals 5 are connected to the circuit board 3. The cell holder 2 connects the battery cells 1 to their grooves 21. (2) The battery unit 10, in which the battery cells 1 and the circuit board 3 are connected in fixed positions, is guided into the peripheral wall of the box-shaped case 4A, and the case 4 and the cell holder 2 are connected by an engagement structure, and the battery unit 10 is connected in a fixed position in the box-shaped case 4A. The cross-sectional views of Fig. 6 and Fig. 7 show the state in which the battery unit 10 is inserted into the box-shaped case 4A. First, as shown in the cross-sectional view of Fig. 6, the battery unit 10 is in an inclined position, and the upper part of the cell holder 2 in the figure is guided first into the box-shaped case 4A, and the first holder locking part 8A is positioned inside the first case locking part 7A. After that, the battery unit 10 in the inclined position is rotated in the direction indicated by the arrow A, and the lower part of the battery unit 10 is inserted into the peripheral wall of the box-shaped case 4A. In this state, as shown in Fig. 7, the side wall 42 of the box-shaped case 4A is elastically deformed, and the second holder locking part 8B is guided beyond the second case locking part 7B to the locking position (see Fig. 4). As shown in Fig. 8, the first holder locking portion 8A is locked to the first case locking portion 7A, and as shown in Fig. 9, the second holder locking portion 8B is locked to the second case locking portion 7B, and the battery unit 10 is placed in a fixed position in the box-shaped case 4A. In this state, the circuit board 3 is sandwiched between the cell holder 2 and the surface plate 41 of the box-shaped case 4A, and the connection terminals 5 are placed in a fixed position. The circuit board 3, which is sandwiched and held in a fixed position, is in close contact with the inner surface of the surface plate 41, and the connection terminals 5 provided on the surface are placed in close contact with the inside of the terminal window 44. (3) After the battery units 10 are placed in their designated positions in the box-shaped case 4A, the cover case 4B is connected to the opening of the box-shaped case 4A to complete the battery pack 100. [Industrial Applicability]

[0059] The battery pack according to the present invention, which has a connection terminal provided in the terminal window 44 of the case, is suitably used as a power source for portable devices such as cameras, music players, and power tools. [Explanation of symbols]

[0060] 100…Battery pack 1. Battery cell 2…Cell holder 3…Circuit board 4. Case 4A…Box case 4B…Lid case 5. Connection terminal 5a…Power terminal 5b…Signal terminal 6…Latching part 7…Case locking part 7A…First case locking portion 7B...Second case locking portion 7a…Inclined rib 7b…Main body wall 7c…Slanted surface 8…Holder locking part 8A…First holder locking portion 8B...Second holder locking portion 10…Battery unit 11...Lead plate 12…Double-sided adhesive tape 21…Groove 22...End plate part 22a...Through hole 23…Support rib 24…Fitting protrusion 25…Step 26...Facing wall 27...Support part 31...Terminal area 34…Mating recess 41…Surface plate 42…Side wall 42A…Vertical side wall 42B…Slanted side wall 43...End wall 44…Terminal window 48…Connecting hook 49…Hook

Claims

1. a battery unit in which battery cells are arranged in fixed positions using cell holders; a circuit board disposed at a fixed position of the battery unit; a case that houses the circuit board and the battery unit; Equipped with the circuit board has a plurality of connection terminals fixed to a surface thereof for connection to an external device; the case includes a surface plate having a terminal window through which the connection terminal is exposed to the outside, the circuit board is connected to a fixed position of the cell holder, and is sandwiched between the battery unit and the surface plate having the terminal window opened therein, and is disposed at a fixed position within the case, with the connection terminals exposed to the terminal window; the cell holder and the case are connected by a locking structure in which a holder locking portion provided on the cell holder and a case locking portion provided on the case are connected by a locking structure, The case, a box-shaped case formed into a box shape by providing a peripheral wall consisting of a side wall and an end wall around the surface plate; a cover case that closes the opening of the box-shaped case, The box-shaped case has the terminal window opened in the surface plate, The cell holder is connected to the box-shaped case by the locking structure, the circuit board is sandwiched between the cell holder and the box-shaped case, and the connection terminal is disposed in an exposed position of the terminal window.

2. 2. The battery pack according to claim 1, The outer peripheral edge of the circuit board and the cell holder are connected by a fitting structure in which a fitting convex portion is guided into a fitting concave portion, and the circuit board is connected to a fixed position of the cell holder in the battery pack.

3. 3. The battery pack according to claim 2, The circuit board has a fitting recess on an outer periphery thereof, the cell holder has a fitting protrusion that is guided by the fitting recess to place the circuit board in a fixed position, The battery pack has a fitting structure in which the fitting convex portion is guided into the fitting concave portion, and the circuit board is connected to a fixed position of the cell holder.

4. 4. The battery pack according to claim 2 or 3, The circuit board has a terminal area on both sides of which the connecting terminals are provided, and the fitting recesses are provided on the circuit board.

5. 5. The battery pack according to claim 1, the circuit board has the connection terminals on a surface thereof; The cell holder is integrally formed with a plurality of support ribs for supporting the rear surface of the circuit board.

6. 6. The battery pack according to claim 1, the box-shaped case has the case engaging portions protruding from the inner surfaces of the pair of side walls, The cell holder has a holder locking portion that is locked to the case locking portion.

7. 7. The battery pack according to claim 6, The pair of side walls of the box-shaped case are A vertical side wall connected to the surface plate in a vertical position; a slanted side wall connected to the surface plate in an inclined position; The case locking portion is a first case engaging portion provided on an inner surface of the vertical side wall; a second case engaging portion provided on an inner surface of the inclined side wall, The battery pack has the first case engaging portion protruding higher than the second case engaging portion.

8. 8. The battery pack according to claim 7, The battery pack has the terminal window formed in the side edge of the surface plate to which the vertical side wall is connected.

9. 9. The battery pack according to claim 7 or 8, the side wall of the box-shaped case has elasticity that allows the holder locking portion to move beyond the case locking portion to a locking position; The side wall is elastically deformed, and the holder locking portion is disposed at the locking position of the case locking portion.

10. 10. The battery pack according to claim 6, The pair of side walls of the box-shaped case are the vertical side wall perpendicularly connected to the surface plate; the inclined sidewall being connected to the surface plate at an obtuse angle; The battery pack has a curved shape in which the inclined side wall protrudes outward from a central portion.

11. 9. The battery pack according to claim 8, The case locking portion is The holder has an inclined surface with an upward inclination toward the insertion direction of the holder locking portion, The holder locking portion moves along an inclined surface and is guided to a locking position of the case locking portion.

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