JP2012079536A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack excellent in impact resistance and capable of being expected to exert favorable battery characteristics, even if an impact due to fall of the battery pack is applied on around an external connector.SOLUTION: In an inside of a battery pack 1, a substrate holder 5 is disposed on the top face of a unit cell 4, and a protection circuit board 6 is positioned on the substrate holder to be disposed. A projection 51 is provided to the substrate holder 5 to be brought into contact with the rear face (a second main surface 60B) of a substrate body 60, which corresponds to a position of an external connector 61 standing on a first main surface 60A of the protection circuit board 6. The projection 51 has a form where a plurality of ribs 510, 511,...are crossed in a parallel-cross shape.

Description

  The present invention relates to a battery pack, and more particularly to a drop-resistant structure of a battery pack in which an external connector protrudes outward from an exterior case.

In recent years, a battery pack using a secondary battery that can be repeatedly charged and used as a unit cell has been widely used. The battery pack has a relatively high energy density and is widely used as a main power source or a backup power source for a notebook personal computer (notebook PC), a mobile phone, a PDA, and other various electronic devices.
A typical battery pack has a configuration in which a rectangular parallelepiped flat secondary battery (lithium ion battery) is a unit cell, and a protection circuit board is electrically connected to the unit cell. The protection circuit board is disposed on one side surface of the unit cell and exposes the external connection terminals on the board. And a unit cell and a protection circuit board are stored in the exterior case which consists of a pair of cases, and the joint of a pair of cases is welded by the ultrasonic welding method etc. The protection circuit board is positioned by positioning ribs formed on the inner surfaces of the pair of cases (see, for example, Patent Document 1).

JP 2006-179212 A JP 2010-27485 A

  However, in the conventional battery pack having the above configuration, when external force is applied to the external connector due to an impact such as dropping, the external connector suddenly presses the protective circuit board and the board is bent and damaged (folding, cracking, etc.) May occur). In addition, due to the deformation of the substrate accompanying such a sudden pressing of the external connector, an electrical element such as a ceramic capacitor mounted on the protection circuit substrate can be destroyed.

Particularly in recent years, in order to meet demands for reducing the size and weight of battery packs, the outer case member and the substrate member may be made thinner. In this case, the above-described problem becomes more prominent.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery pack that is excellent in impact resistance and can be expected to exhibit good battery characteristics even when the vicinity of an external connector is dropped.

  In order to solve the above problems, the present invention provides a rectangular parallelepiped unit cell and a circuit board connected to the unit cell and having an external connector erected on the first main surface, wherein a part of the external connector is externally provided. A battery pack housed in an outer case in a projecting manner, wherein a substrate holder made of an insulating member is disposed between one side surface of the unit cell and the circuit board, and at least a first main surface In the predetermined region of the second main surface corresponding to the standing position of the external connector, the circuit board comes into contact with the board holder so that the circuit board is supported by the unit cell via the board holder. It was set as the composition.

Here, a protrusion may be formed on the substrate holder, and the protrusion may be in contact with a predetermined region of the second main surface of the circuit board.
In this case, the protrusion may be configured by ribs arranged in an intersecting manner, and the top of the rib may be in contact with a predetermined region of the second main surface.
Further, the outer case may be configured such that the first case and the second case are ultrasonically welded to each other.

  In addition, positioning ribs for positioning the circuit board can be formed on the inner surface of the exterior case by contacting the first main surface of the circuit board.

  In the battery pack according to the present invention, a predetermined region of the second main surface corresponding to at least the standing position of the external connector on the first main surface of the circuit board (that is, the back surface of the standing position is the upper surface of the unit cell). In this way, the vicinity of the standing position of the external connector of the circuit board is reliably supported on the upper surface of the unit cell via the board holder.

  Therefore, if the user accidentally drops the battery pack, even if a sudden impact (pressing force) is applied to the external connector, the projecting portion receives the impact via the circuit board, and the external connector is affected by the reaction force. Press back. Thereby, the depression of the external connector is effectively suppressed, and damage to the circuit board and the mounted electrical element in the region corresponding to the standing position of the external connector is prevented. As a result, the reliability of the battery pack can be significantly improved.

  Furthermore, in the present invention, it is not necessary to lock the external connector or the circuit board to the rib on the inner surface of the case inside the battery pack by using the board holder having the above configuration. Therefore, the problem that the case is greatly deformed by the impact received by the external connector can also be prevented.

1 is a perspective view showing an external appearance of a battery pack according to Embodiment 1. FIG. FIG. 3 is a development view (assembly diagram) illustrating an internal configuration of the battery pack according to the first embodiment. It is a partial perspective view of a battery pack showing the composition near the upper surface of a protection circuit board. It is a perspective view which shows the structure of a substrate holder. It is a fragmentary sectional view showing peripheral composition of a substrate holder and a protection circuit board. It is a perspective view which shows the modification of a substrate holder.

Hereinafter, embodiments of the present invention will be described.
Needless to say, the present invention is not limited to the following configurations, and can be modified as appropriate without departing from the technical scope of the present invention.
<Embodiment 1>
(External configuration of battery pack 1)
An external configuration of the battery pack 1 according to the embodiment will be described with reference to FIG. FIG. 1 is an external view of the battery pack 1.

As shown in FIG. 1, the battery pack 1 has an exterior case formed by ultrasonically welding a lower case 2 and an upper case 3, wherein the X direction is the thickness direction, the Y direction is the width direction, and the Z direction is the height direction. It has a flat rectangular parallelepiped appearance. On the upper surface in the Z direction of the battery pack 1, an external connector 61 that includes a metal terminal (not shown) projects outwardly along the Z direction.
Reference numeral 24 denotes a label covering the test point terminal.

(Internal configuration of battery pack 1)
Next, the internal configuration of the battery pack 1 will be described with reference to FIG. FIG. 2 is an exploded perspective view showing the internal configuration of the battery pack 1.
As shown in FIG. 2, the battery pack 1 includes a unit cell 4 as a main component, and includes a substrate holder 5, a protection circuit substrate 6, and the like housed in an exterior case (lower case 2 and upper case 3). ing.

(Unit cell 4)
The unit cell 4 contains an electrode body (not shown) in which positive and negative bipolar plates are laminated via a separator, and an electrolytic solution impregnated therein, inside a rectangular parallelepiped flat rectangular bottomed outer can 42. With the sealing plate 41 fitted to the opening of the outer can 42, the periphery of the sealing plate 41 is laser welded to the opening of the outer can 42 and internally sealed. On the surface of the sealing plate 41 constituting one side surface (upper surface) of the unit cell 4, a positive electrode terminal 43 is formed at the center, a clad plate 47 (negative electrode terminal) in which a Ni / Al material is laminated at one end, and the other end. Safety valves 44 are arranged respectively.

Since the outer can 42 and the sealing plate 41 are made of an alloy material of aluminum (Al), the clad plate 47 is joined so that the Al side surface faces the sealing plate 41 side.
The positive terminal 43 is insulated from the sealing plate 41 side using an insulating gasket (not shown).
The safety valve 44 is formed of a metal thin film, and is broken when the abnormal internal pressure of the unit cell 4 is increased to release the pressure to the outside, thereby suppressing damage to the unit cell 4 and its peripheral components.

Here, as the unit cell 4, a square lithium ion secondary battery having excellent charge capacity is used. The type of the unit cell 4 is not limited to this, and other prismatic secondary batteries such as a nickel metal hydride battery and a nickel cadmium battery can be used.
Double-sided tape 48 is attached to both main surfaces of the outer can 42 (only the double-sided tape 48 on the front main surface is shown in FIG. 2). This is means for adhering to the inner surface of the outer case (upper case 3, lower case 2) and fixing the unit cell 4 inside the case.

(Protection circuit board 6 etc.)
Next, FIG. 3 is a perspective view showing a configuration in the vicinity of the protection circuit board 6 inside the battery pack 1.
As shown in the figure, the protective circuit board 6 is made of a composite material containing glass, epoxy resin, or the like, and is mainly composed of a strip-shaped board body 60 whose longitudinal direction is the Y direction, and both main surfaces (first main surface). 60A and the second main surface 60B) are configured by mounting various electric elements. And it arrange | positions in the sealing plate 41 vicinity so that the main surface of the board | substrate body 60 may become parallel with respect to the upper surface of the sealing plate 41. FIG. On the upper surface (first main surface 60A) of the protection circuit board 6, a predetermined electrical element such as a ceramic capacitor is mounted, and an external connector 61 is erected near the center thereof.

Note that conductive lands (not shown) are formed in the lower surface (second main surface 60B (not shown)) of the protection circuit board 6 in the vicinity of both ends in the longitudinal (Y) direction of the board body 60, and each conductive material is formed as shown in FIG. Lead plates 65 and 66 are electrically connected to the lands by series spot welding.
The lead plates 65 and 66 are made of a plate-like metal material (NiP or Ni—Fe—Ni clad material) having excellent electrical conductivity and welding characteristics, and are configured by bending a long metal member when deployed. The lead terminals 463 and the clad material 47 are electrically connected to each other by series spot welding.

A safety element (PTC main body 462) is electrically connected to the positive electrode terminal 43 and the lead plate 66 by direct spot welding via lead terminals 461 and 463, thereby forming the PTC element 46.
The PTC element 46 interrupts energization when the temperature of the unit cell 4 rises excessively during charging / discharging of the battery pack 1. When attaching the PTC element 46 to the unit cell 4, the lead terminals 461, 463, etc. are in contact with the sealing plate 41 side to cause a short circuit, and the safety valve 44 is closed to the substrate 6 side so as not to cause malfunction. The insulating plate 45 is disposed between the sealing plate 41 and a predetermined interval, and the PTC element 46 is placed thereon.

The insulating plate 45 can be made of various resin materials, but is preferably heat resistant and has a strength that does not cause deformation when the resin molding 10 is molded. A suitable material is polycarbonate (PC) resin.
The insulating plate 45 can also be fixed to the unit cell 4 side using an insulating tape (not shown).

(Substrate holder 5)
FIG. 4 is a perspective view showing a specific configuration of the substrate holder 5, which is a main characteristic part of the present invention.
The substrate holder 5 shown in the figure is mainly composed of a strip-shaped substrate holder main body 55 having a longitudinal direction in the Y direction, and a protruding portion 51 is formed at the center of one main surface (upper surface), and one end in the longitudinal direction (Y). An opening 52 is formed on the side and a flat plate 54 is formed on the other end in the same direction. It is formed by injection molding an insulating member such as polycarbonate (PC) resin. The protruding portion 51 is a predetermined region of the second main surface 60B that overlaps with the standing position of the first main surface 60A of the substrate body 61 on which the external connector 61 is disposed (in the battery pack 1, almost the same in the battery pack 1). It is formed in conformity with the position in contact with the central region).

The protrusion 51 includes a plurality of ribs 510, 511, 512, 513, 514 and 515 that extend in the crossing direction so as to form a substantially cross-beam shape and have the same height (height in the Z direction). . The protrusion 51 is disposed for the purpose of supporting the protection circuit board 6 from the second main surface 60B side.
The tops of the ribs 510 and 511 are fitted with fitting grooves 63A, 63B, and 63C (see FIG. 3) formed on the side surface of the substrate body 60 of the protection circuit board 6 to position the board 6. Three fitting claws 53A, 53B, and 53C are disposed.

The opening 52 is a hole formed to avoid interference between the substrate holder 5 and the PTC main body 462. The flat plate portion 54 is formed as a flat region that matches the shape of the electric element and the lead plate 66 mounted on the protection circuit board 6.
In the battery pack 1, the protection circuit board 6 is connected to the unit cell 4 side by lead plates 65 and 66, and the board holder 5 is sandwiched between the protection circuit board 6 and the unit cell 4. . Therefore, the protection circuit board 6 is satisfactorily held with respect to the board holder 5, and once assembled, it is easily fixed without coming off.

(Appearance case)
Returning to FIG. 2, the upper case 3 and the lower case 3 are dish-shaped bodies each having a rectangular bottom surface made of an insulating member (made of polycarbonate as an example). The lower case 3 is formed deep in the X direction so that the unit cell 4, the substrate holder 5, and the protection circuit substrate 6 can be accommodated, and the upper side surface of the external connector 61 is partially exposed to the outside. A surrounding portion 22 that covers the connector 61 from the periphery is formed. In addition, an opening 23 is provided for energizing the test point 62 on the protection circuit board 6 from the outside. The opening 23 is covered with a label 24 after the test (see FIG. 1).

The upper case 3 and the lower case 2 are respectively formed with a welding rib 31 and a welding groove 21 along the periphery of each opening.
In addition, the upper inner surface along the Z direction (that is, the protruding direction of the external connector 61) of each case 2, 3 is in contact with the protective circuit substrate 6 on the upper surface (first main surface 60 </ b> A). A plurality of ribs 25 and 32 are positioned upright (see FIG. 5). Although the ribs 25 and 32 are not essential in the battery pack 1, the protection circuit board 6 can be positioned more reliably by using the ribs 25 and 32.

In the manufacturing process, the upper case 2 and the lower case 3 accommodate the protection circuit board 6, the substrate holder 5, and the unit cell 4 and the like, and then fit the welding ribs 31 into the welding grooves 21 with the main surface portions 20 and 30 facing each other. Internal sealing is achieved by ultrasonic welding the welding rib 31 and the welding groove 21 to each other.
(About the effect of the substrate holder 5 in the battery pack 1)
FIG. 5 shows a cross-sectional view of the battery pack 1 in FIG. In the figure, the internal configuration of the unit cell 4 is omitted.

  As shown in FIGS. 3 and 4, the protection circuit board 6 having the above configuration is fitted with the fitting grooves 63 </ b> A, 63 </ b> B, 63 </ b> C of the board body 60 with the fitting claws 53 </ b> A, 53 </ b> B, 53 </ b> C of the board holder 5. . And as shown in FIG. 5, the board | substrate body 60 is supported by the top part of each rib 510-513 of the protrusion part 51 in the back surface. The substrate holder 5 is disposed in contact with one side surface (the upper surface of the sealing plate 41) of the unit cell 4 at the back rib 57. In this state, the protection circuit substrate 6, the substrate holder 5, and the unit cell 4 are a pair of cases. It is housed in 2, 3 and sealed inside.

Inside the battery pack 1, at least a region of the lower surface (second main surface 60 </ b> B) of the substrate body 60 corresponding to the standing position of the external connector 61 in the protection circuit substrate 6 is arranged on the upper surface of the unit cell 4. It is supported by the protrusion 51 of the substrate holder 5. The bottom surface of the unit cell 4 is in contact with the bottom of the outer case, and both main surfaces of the unit cell 4 are fixed to the inner surface of the outer case with a tape 48.
Therefore, even if the user drops the battery pack 1 and a sudden impact (pressing force) is applied to the external connector 61 from the reverse Z direction as shown in FIG. Then, the external connector 61 is pushed back in the Z direction by the reaction force. As a result, the problem that the external connector 61 sinks into the battery pack is prevented, so that the protective circuit board 6 is mounted on the board body 60 or the board body 60 without causing excessive deformation (bending) of the protection circuit board 6. Damage to electrical elements such as ceramic capacitors can be effectively prevented. Therefore, the reliability of the battery pack 1 can be dramatically improved.

  Further, in the battery pack 1, the ribs 25 and 32 on the inner surfaces of the cases 2 and 3 are in contact with the upper surface (first main surface 60A) of the protective circuit board 6 and regulate the floating of the board 6 in the Z direction. It does not support or lock the substrate 6 from the second main surface 60B side. Therefore, even when the external connector 61 receives an impact as described above, the impact force does not directly reach the ribs 25 and 32, so that the problem that the case is greatly deformed through the ribs 25 and 32 can be prevented.

Furthermore, such a battery pack 1 can be implemented at a relatively low cost by using an injection molded substrate holder 5. Therefore, the present invention is very excellent in terms of feasibility.
(About the shape of the protrusion provided on the board holder)
In the battery pack of the present invention, in order to efficiently obtain the above-described effects, at least a predetermined region of the second main surface 60B corresponding to (overlapping) the standing position of the external connector 61 on the first main surface 60A protrudes. Care is taken to ensure that the portion 51 abuts against the second major surface 60B.

  In this case, the larger the contact area of the protrusion 51 of the substrate holder 5 that contacts the protection circuit board 6 is, the higher the effect of preventing damage to the protection circuit board 6 is. Therefore, for example, the width of the ribs 510, 511,... Is increased to ensure the area of the top as wide as possible, or the number of the ribs 510, 511,. A device to increase the position is effective. In this way, since the rigidity of the protrusion 51 itself is also improved, a dramatic improvement in the durability of the battery pack 1 can be expected.

The ribs 510, 511,... Are not limited to a continuous belt-like pattern as shown in FIG.
FIG. 6 is a perspective view showing a modified example of the substrate holder. For example, as shown in the holder 5A in FIG. 6A, a flat trapezoidal protrusion 51A can be provided.
Or like the holder 5B of FIG.6 (b), the column-shaped protrusion part 51B can also be provided in multiple numbers intermittently in XY each direction. Also, the ribs shown in FIG. 4 do not need to cross each other. For example, they may be arranged in parallel in the X direction (or Y direction) with the Y direction (or X direction) as the longitudinal direction.

<Other matters>
In the battery pack 1 according to Embodiment 1, the configuration in which one unit cell 4 is built in is illustrated, but the present invention can also be applied to a battery pack in which a plurality of unit cells are built in.
Further, the side surface of the unit cell 4 to which the protection circuit board 6 and the substrate holder 5 are attached is not limited to the side surface on which the sealing plate 41 is disposed (that is, the upper surface of the sealing plate 41), and the other side surface of the unit cell 4 (for example, Any one of two side surfaces along the XZ plane) may be used.

Further, the safety element is not limited to the PTC element 46, and other safety elements may be used. For example, a thermal element such as a NTC (Negative Temperature Coefficient) element or a thermal fuse element, and various electric elements used for other battery control are mentioned.
Although the configuration example using the protection circuit board 6 as the circuit board disposed in the board holder 5 is shown, it is needless to say that a circuit board other than the protection circuit board 6 may be used.

The battery pack according to the present invention can be widely used as a main power source for small electronic devices such as portable DVD players, portable GPS, and transceivers, in addition to notebook computers and PDAs. Alternatively, it can be applied to relatively large devices such as power assist bicycles and electric tools.
The present invention is effective for realizing a battery pack having high appearance quality in any application.

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Lower case 3 Upper case 4 Unit cell 5, 5A, 5B Substrate holder 6 Protection circuit board 20, 30 Main surface part 21 Welding groove 22 Outer part 31 Welding rib 42 Outer can 45 Insulating board 46 PTC element 47 Clad board 51, 51A, 51B Protrusion 52 Opening 53A, 53B, 53C Fitting Claw 56 Bottom 57 Back Rib 60 Substrate Main Body 60A First Main Surface (Substrate Main Body Upper Surface)
60B Second main surface (bottom surface of substrate body)
61 External connector 63A, 63B, 63C Fitting groove 65, 66 Lead plate 510, 511, 512, 513 Rib

Claims (5)

A rectangular parallelepiped unit cell and a circuit board connected to the unit cell and having an external connector erected on the first main surface are housed in an exterior case with a portion of the external connector protruding outward. A battery pack comprising:
A substrate holder made of an insulating member is disposed between one side surface of the unit cell and the circuit board,
At least in a predetermined region of the second main surface corresponding to the standing position of the external connector on the first main surface, the circuit board comes into contact with the substrate holder, so that the circuit board is inserted into the element through the substrate holder. A battery pack characterized by being supported by a battery. 2. The battery pack according to claim 1, wherein a protrusion is formed on the substrate holder, and the protrusion is in contact with a predetermined region of the second main surface of the circuit board. 3. The battery pack according to claim 2, wherein the protruding portion is configured by ribs arranged in an intersecting manner, and a top portion of the rib is in contact with a predetermined region of the second main surface. The battery pack according to any one of claims 1 to 3, wherein the outer case is formed by ultrasonically welding the first case and the second case together. The positioning rib for positioning the said circuit board is formed in the inner surface of the said exterior case by contacting the 1st main surface of a circuit board. The any one of Claims 1-4 characterized by the above-mentioned. The battery pack described in 1.

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