JP3592193B2 - Battery pack - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery pack including a secondary battery.
[0002]
[Prior art]
In portable information devices such as mobile phones and mobile computers, portable audio devices, and the like, there is an increasing demand for smaller, lighter, and thinner devices to improve portability. It is no exaggeration to say that the key to this is the battery power supply device. In particular, there is a strong demand for a lighter and thinner battery power supply device using a secondary battery.
[0003]
The reduction in weight and thickness of a battery power supply (battery pack) using a secondary battery is to achieve a reduction in weight and thickness of the secondary battery without any modification. A secondary battery in which a laminate sheet covered with a plurality of resin layers is used as an outer case and in which a power generation element is sealed has been put to practical use. By using a secondary battery having this laminate sheet as an outer case, a lighter and thinner battery pack can be configured. In particular, when a plurality of secondary batteries are connected in parallel to increase the battery capacity, or when a plurality of secondary batteries are connected in series to obtain a relatively high voltage, weight reduction is further promoted. A thin battery pack can be formed, and it is possible to meet the demand for lighter and thinner portable devices.
[0004]
When the battery pack is configured in this manner, it is necessary to take waterproof measures at least to the extent of waterproofing for living so that water does not enter the pack case. The problem in applying this waterproofing measure is the processing of the external input / output terminals of the battery pack, and there is an electrical connection extending from the contact surface exposed to the outside of the pack case to the inside. This is where the water enters.
[0005]
As a countermeasure against this, in the prior art, as shown in FIG. 12, the insertion pieces 55a, 55a of the external input / output terminal 55 inserted from the outside into the slit holes 51, 51 formed in the terminal mounting recess 52 of the pack case 50. A rubber member 53 covering the insertion pieces 55a, 55a is provided on the inner surface side of the pack case 50 so as to fill the terminal mounting recesses 52, and a gap between the insertion pieces 55a, 55a and the slit holes 51, 51 is provided. In the water.
[0006]
[Problems to be solved by the invention]
However, in the conventional configuration, the rubber member 53 is required to prevent water from entering from the external input / output terminal, and as the number of constituent members increases, the mounting work is also required, leading to an increase in the cost of the battery pack. In addition, in a battery pack that is reduced in size, weight, and thickness, the mounting operation of the rubber member 53 is difficult, and the reduction in weight is impaired.
[0007]
An object of the present invention is to provide a battery pack in which a waterproof measure for a mounting portion of an external input / output terminal is easily and inexpensively configured.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a battery pack in which a secondary battery is housed in a pack case, and an external input / output terminal connected to the secondary battery contacts an external position at a predetermined position of the pack case. A battery pack mounted with its surface exposed, wherein at a predetermined position of the pack case, an outer surface side is opened in a slit shape, and an inner surface side is formed with a mounting hole closed with a thin-walled sealing film. The external input / output terminal rises at a right angle from the contact surface, and is formed with an insertion piece provided with a detent projecting more than the length of the mounting hole on both sides in the width direction thereof. By inserting the insertion piece from the outer surface side and press-fitting the external input / output terminal, the sealing film is broken by the tip of the insertion piece, the detent is locked to the inner surface edge of the mounting surface, and the external input / output Terminal is a pack case It is configured to be attached and is characterized in.
[0009]
According to the above configuration, when the external input / output terminal is attached to the pack case, the tip of the insertion piece breaks the sealing film in the mounting hole and enters the pack case. Are tightly closed to close the gap between the insertion piece and the mounting hole, thereby preventing water from entering the pack case from outside through the gap. In addition, when the insert is inserted into the mounting hole to the insertion end, the stopper formed on the insert is locked to the peripheral surface of the mounting hole, so the external input / output terminal is fixed to the pack case only by the insertion operation can do.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings to facilitate understanding of the present invention. The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0011]
The embodiment of the present invention shows a configuration of a battery pack in which three secondary batteries 1 each containing a power generation element are connected in parallel in an outer case formed of a laminate sheet, as shown in FIG. By housing the three secondary batteries 1 and the circuit board 3 in the lower case 2b constituting the pack case 2, and joining the upper case 2a to the lower case 2b, the external view of FIG. As shown, the battery pack is formed in a flat secondary battery pack.
[0012]
The secondary battery 1 is configured as a lithium polymer secondary battery, and is formed by folding a laminate sheet in which both surfaces of a metal layer are covered with a plurality of resin layers into two, as shown in FIG. The power generation element is accommodated in a concave portion 29 formed on one side of the laminate sheet to be folded, and the three sealing sides P1, P2, and P3 are heat-sealed as shown in FIG. And the positive electrode lead 11 connected to the positive electrode plate of the laminated electrode plate 30 and the negative electrode lead 12 connected to the negative electrode plate of the power generating element are drawn out from the same sealing side P3 of the outer case 4. Have been. As shown in FIG. 2C, the seal sides P1 and P2 on both sides on which the outer case 4 is formed are bent and fixed on the flat plate surface with an adhesive tape 31 to reduce the width dimension.
[0013]
As shown in FIG. 3, the secondary battery 1 is disposed in a lower case 2b formed in a half-shell by resin molding. As shown, battery positioning ribs 6a, 6b, 6c for individually positioning the plurality of secondary batteries 1 are formed on the lower case 2b, and surround the respective secondary batteries 1 together with the inner peripheral wall 28 of the lower case 2b. A position regulating wall for regulating the storage position is formed, and the secondary battery 1 is positioned and held at four sides thereof. An external input / output terminal 25 including a positive input / output terminal 25a, a negative input / output terminal 25b, and a temperature detection terminal 25c is attached to the bottom surface of the lower case 2b, and a positive lead plate 22a, a negative lead plate 22b, and a temperature detection lead A lead plate 22 composed of a plate 22c is joined, and one end of each is located below the position where the circuit board 3 is provided. The circuit board 3 is positioned by the board positioning ribs 7a and 7b and the inner peripheral wall 28. When the circuit board 3 is disposed on the lower case 2b, the plus connection terminal 20a, the minus connection terminal 20b formed on the circuit board 3 The lead plates 22 corresponding to the respective holes of the connection terminals 20 formed of the temperature detection connection terminals 20c are respectively inserted. Therefore, the lead plates 22 and the connection terminals 20 are soldered and connected, and the circuit board 3 is connected to the external input / output terminals. 25 is obtained. With this connection configuration, the secondary battery 1 can be charged and discharged from the external input / output terminal 25 through the circuit board 3.
[0014]
As shown in FIG. 4, the external input / output terminals 25 are mounted on terminal mounting recesses 61 which bulge out on the outer surface side of the lower case 2b and have recesses formed on the inner surface side. FIGS. 5, 6, and 7 show the mounting structure of the external input / output terminal 25. FIG. As shown in FIG. 5 (a), a terminal mounting recess 61 formed in the lower case 2b has a positive input / output terminal 25a, a negative input / output terminal 25b, and a temperature detection terminal 25c constituting the external input / output terminal 25. Mounting holes 60, 60 are formed in a slit shape corresponding to the width and thickness of the insertion piece 62 and open toward the outside, and the inside thereof has a sealing film 60a formed into a thin film during resin molding. It is closed by 60a. FIG. 6 shows the shape of the plus input / output terminal 25a. A pair of insertion pieces 62, 62 are formed at right angles from both sides of a contact surface 65 exposed to the outside from the lower case 2b and contacting the device-side probe. A stopper 63 is formed on each side of the tip. Further, a lead piece 64 is formed so as to extend from one insert piece 62, and a lead plate 22 for connection to the circuit board 3 is joined thereto. Note that the minus input / output terminal 25b is also formed in the same shape, and the temperature detection terminal 25c is formed only in a narrow width, and is similar in structure. As will be described, other terminals are similarly attached.
[0015]
When the plus input / output terminal 25a shown in FIG. 6 is pressed into the mounting hole 60 from the lead piece 64, the sealing film 60a is broken and the lead piece 64 is inserted into the inside of the lower case 2b. When the sealing film 60a is pressed into the holes 60, 60, the sealing film 60a is entirely broken, and the stopper 63 is locked at the inner end of the mounting hole 60 at the insertion end as shown in FIG. It is fixed to the case 2b. Further, since the broken sealing film 60a is in close contact with the insertion piece 62, it is possible to prevent water from entering the lower case 2b from the gap between the mounting hole 60 and the insertion piece 62. Although this waterproofing effect is about the level of waterproofing for living, it can be protected from raindrops and waterdrops and functions sufficiently as a battery pack.
[0016]
When the external input / output terminals 25 and the lead plate 22 are attached, and the three secondary batteries 1 are positioned and arranged on the lower case 2b on which the circuit board 3 is provided, as shown in FIG. The tips of the positive electrode lead 11 and the negative electrode lead 12 are located on the soldering lands 21 formed on the circuit board 3. Each of the positive electrode lead 11 and the negative electrode lead 12 is ultrasonically welded to a connecting member 19 formed of a nickel plate at its tip in advance, and the connecting member 19 is connected to a soldering land 21 formed by a conductor pattern on the substrate 10. By soldering, three secondary batteries 1 are connected to the circuit board 3. The connection member 19 is used because the positive electrode lead 11 is made of aluminum and cannot be soldered, so that it can be easily soldered.
[0017]
The circuit board 3 is formed as a double-sided board, and the conductor patterns 9 for connecting the respective soldering lands 21 to the respective rechargeable batteries 1 in parallel are formed on the back surface. The circuit patterns of the overcurrent protection element 8 and the protection circuit 5 which are connected and constitute the battery protection device are formed.
[0018]
By connecting each of the secondary batteries 1 to the circuit board 3, each of the secondary batteries 1 is connected in parallel with the overcurrent protection element 8 connected in series as shown in the circuit diagram of FIG. The obtained three secondary batteries are connected to the connection terminal 20 through the protection circuit 5 to obtain a circuit configuration. The overcurrent protection element 8 is designed to blow out when an excessive charge / discharge current flows through each of the secondary batteries 1 to prevent damage to each of the secondary batteries 1. The protection circuit 5 is formed by intensively mounting a plurality of electronic components including IC components at predetermined positions on the substrate 10 and covering the electronic components with a resin mold 26. When an abnormal state of the secondary battery pack is detected, the input / output circuit is shut off to protect the secondary battery 1 from the abnormal state. The overcurrent protection element 8 and the protection circuit 5 constitute a battery protection device, which prevents a device connected to the secondary battery pack from being damaged, malfunctioning, or being damaged due to improper use. Can be.
[0019]
After all the components are accommodated in the lower case 2b in this manner, as shown in FIG. 1, the upper case 2a is ultrasonically bonded to the lower case 2b, and the plurality of secondary batteries 1 are placed in the pack case 2. The sealed battery pack is completed.
[0020]
As shown in FIG. 10, the upper case 2a has side peripheral ribs 33 that fit into side peripheral grooves 34 formed between the inner peripheral wall 28 and the outer peripheral wall 27 of the lower case 2b, and is formed on the lower case 2b. The battery holding rib 36 fitted in the battery holding groove 35 between the battery positioning ribs 6b, 6b, and the lead side holding rib 37 fitted between the battery positioning rib 6a and the board positioning rib 7a formed in the lower case 2b. And a board holding rib 38 for regulating the position of the circuit board 3 in the thickness direction. Further, positioning ribs 39 are formed at three corners, and are configured to be able to fit into positioning portions 40 formed on the lower case 2b.
[0021]
When the positioning rib 39 is inserted into the positioning portion 40 of the lower case 2b and the upper case 2a is positioned on the lower case 2b, and the upper case 2a is pressed toward the lower case 2b, the side circumferential ribs 33 are inserted into the side circumferential grooves 34. The battery holding rib 36 fits into the battery holding groove 35, and the lead side holding rib 37 fits between the battery positioning rib 6a and the substrate positioning rib 7a. The V-shaped rib formed at the tip of each rib is formed at the bottom of the groove. Fit into the V-shaped groove. In this state, the upper case 2a and the lower case 2b are pressed by the horn of the ultrasonic welding device and the receiving jig, and ultrasonically excited from the horn, the upper case 2a and the lower case 2b become V-shaped ribs 42 and V It is welded between the U-shaped grooves 43. By fitting the upper case 2a and the lower case 2b into a structure in which the convex portion fits into the concave portion in this way, reliable positioning can be performed and the rigidity of the pack case 2 can be increased. Also, by ultrasonically joining the tips of the projections at the bottoms of the recesses, the joints are not exposed to the outside, and are formed not only in the peripheral portion but also in a position surrounding the plurality of secondary batteries 1. Can be improved in strength against twisting and bending.
[0022]
FIGS. 11A and 11B show a state in which the secondary battery 1 is accommodated in the pack case 2, wherein FIG. 11A is a cross-sectional view of the secondary battery 1 in a lateral direction, and FIG. is there. As shown in the figure, a portion of the lower case 2b that is in contact with the flat surface of the secondary battery 1 is formed on a thin-walled elastic deformation surface 44. The elastic deformation surface 44 is thinly formed at a position lower by a step H from the periphery thereof, and elastically deforms while maintaining a flat state when the thickness of the secondary battery 1 changes due to expansion. As shown in FIG. 4, a thin stainless steel plate 45 is attached to the elastic deformation surface 44 in order to prevent the secondary battery 1 from being damaged by piercing with a blade or the like since the elastic deformation surface 44 is formed into a thin wall. The stainless thin plate 45 has a projection 45a formed at a corner thereof to facilitate positioning at the time of sticking, and a portion not covering the elastic deformation surface 44 is provided on four sides to elastically deform the elastic deformation surface 44. It does not hinder the deformation of the part. It should be noted that the secondary battery 1 provided at the position where the external input / output terminal 25 is provided is provided with a thinly formed elastic deformation groove 46, which can similarly cope with a change in the thickness of the secondary battery 1. Like that.
[0023]
When the electrode plate expands due to repeated charge / discharge or aging, when the outer case 4 is formed of a soft material such as a laminate sheet as in the secondary battery 1, the thickness of the secondary battery 1 is reduced. Increases on average and pushes up the elastic deformation surface 44. Since the elastically deformable surface 44 is deformed at its peripheral portion, the central portion of the elastically deformable surface 44 rises in the step H while maintaining a flat state. Therefore, by setting the step H corresponding to the amount of change in the thickness of the secondary battery 1, the thickness of the battery pack does not change due to the change in the thickness of the secondary battery 1, and the battery pack is mounted. It does not affect the devices that do.
[0024]
Further, as shown in FIGS. 10 and 11A, when the swelling portion 47 is formed on the inner surface of the upper case 2a in the longitudinal direction of the secondary battery 1 and the secondary battery 1 is accommodated in the pack case 2. Then, the secondary battery 1 is sandwiched between the elastically deformable surface 44. The elastic deformation surface 44 applies a force in the compression direction to the secondary battery 1 by its elasticity, so that a tension force is constantly applied to the secondary battery 1 and expansion of the electrode plate is suppressed. In addition, the secondary battery 1 in which the outer case 4 is formed of a soft material such as a laminate sheet has a weak force for restraining the stacked electrode plates, and is positioned on the stacked electrode plates when an impact or vibration is applied. Although displacement is likely to occur, the side plate is surrounded by four sides, and a tension force is applied in the thickness direction, thereby restricting the movement of the electrode plate.
[0025]
The configuration of the embodiment described above is a case where three rechargeable batteries 1 are housed in the pack case 2, but the same configuration can be applied to a case where three or less or three or more are used.
[0026]
【The invention's effect】
As described above, according to the present invention, the sealing film broken by press-fitting the insertion piece of the external input / output terminal into the mounting hole is in close contact with the insertion piece, so that the gap between the insertion piece and the mounting hole is reduced. It is buried and can prevent water from entering the pack case. There is no need to prepare a member for this waterproofing, so that the cost of the battery pack can be reduced and the number of man-hours can be reduced.
[Brief description of the drawings]
FIG. 1A is an external view of a secondary battery pack according to an embodiment, and FIG. 1B is a perspective view of the secondary battery pack with a pack case opened.
FIGS. 2A and 2B show a configuration of a secondary battery, in which FIG. 2A is a plan view showing a sealed state of an outer case, FIG. 2B is a side view, and FIG.
FIG. 3 is a plan view showing a configuration of an inner surface side of a lower case.
FIG. 4 is a plan view showing a configuration of an outer surface side of a lower case.
FIGS. 5A and 5B are cross-sectional views of the external input / output terminal mounting structure taken along line BB of FIG.
FIG. 6 is a perspective view showing a configuration of a positive input / output terminal.
FIG. 7 is a cross-sectional view taken along line CC, showing a state where external input / output terminals are attached.
FIG. 8 is a plan view showing a state where a circuit board and a secondary battery are housed on a lower case.
FIG. 9 is a circuit diagram showing an electrical connection of the secondary battery pack.
FIG. 10 is a plan view showing the configuration on the inner surface side of the upper case.
FIGS. 11A and 11B are cross-sectional views of a state in which a secondary battery is housed in a pack case, in which FIG. 11A is a transverse direction of the secondary battery and FIG.
FIG. 12 is a cross-sectional view showing a waterproof structure according to the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Pack case 2a Upper case 2b Lower case 25 External input / output terminal 60 Mounting hole 60a Sealing film 62 Insertion piece 63 Retainer 64 Lead piece 65 Contact surface

Claims (1)

A secondary battery is housed in a pack case formed by resin molding, and an external input / output terminal connected to this secondary battery is a battery pack attached with a contact surface exposed to the outside at a predetermined position of the pack case. So,
At a predetermined position of the pack case, an outer surface side is opened in a slit shape, and an inner surface side is formed with a mounting hole whose opening is closed by a thin-walled sealing film,
The external input / output terminal rises at a right angle from the contact surface, and an insertion piece provided with a detent projecting beyond the length of the mounting hole is formed on both sides in the width direction thereof,
By inserting the insertion piece from the outer surface side of the mounting hole and press-fitting the external input / output terminal, the sealing film is broken by the tip of the insertion piece, and the detent is locked to the inner surface edge of the mounting hole. A battery pack characterized in that external input / output terminals are configured to be attached to a pack case.

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