JP3507397B2 - Battery pack - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery in which a power generating element is housed in an outer case made of a laminate sheet.
The present invention relates to a battery pack containing a plurality of batteries in a pack case.

[0002]

2. Description of the Related Art For portable information devices such as mobile phones and mobile computers, portable audio devices, etc., there is an increasing demand for reduction in size, weight and thickness in order to improve portability. It is no exaggeration to say that the key is the battery power supply device, and in particular, there is a strong demand for reducing the weight and thickness of the battery power supply device using a secondary battery.

To reduce the weight and thickness of a battery power supply device (battery pack) using a secondary battery is to achieve a weight reduction and a thickness reduction of the secondary battery without repairing the metal layer. A secondary battery in which a power generating element is enclosed in a laminated sheet having both surfaces coated with a plurality of resin layers as an outer case has been put into practical use. By using a secondary battery having this laminated sheet as an outer case, a lightweight and thin battery pack can be constructed.

However, the secondary battery 1 having a laminated sheet as an outer case has a soft outer case, and therefore when the battery pack is subjected to shock or vibration, the secondary battery moves due to the weight of the power generating element, and the outer case There is a risk that the foil-shaped lead portion drawn out of the case may be bent or bent, or the outer case may be damaged. Therefore, Japanese Patent Laid-Open No. 11-1
In the configuration disclosed in Japanese Patent No. 11250, a secondary battery having a laminate sheet as an outer case is fixed to the inner surface of the pack case with a double-sided adhesive tape or the like to prevent the secondary battery from moving due to shock or vibration.

[0005]

However, in a secondary battery using a soft outer case such as a laminate sheet, the force of pressing the power generating element by the outer case is a secondary battery in which the power generating element is housed in a metal can. Since the outer case is fixed because it is fixed to the pack case and does not move when shock or vibration is applied, the power generation element housed inside moves and the positive and negative poles move. The lead drawn out from the plate may be broken or bent in the outer case.

Further, the secondary battery having an outer case made of a laminated sheet allows the electrode case to be deformed when the electrode plate expands due to repeated charging / discharging or aging, and therefore the outer case is soft, This increases the thickness of the secondary battery. The pack case containing such a secondary battery may be deformed due to an increase in thickness,
There is a risk that the device with the battery pack may be adversely affected.

The object of the present invention is to regulate the accommodation position of the secondary battery in the pack case to prevent the positional displacement and to cope with the thickness change of the secondary battery, and to use the laminate sheet as the outer case. It is an object of the present invention to provide a battery pack that solves the problems in forming a thin battery pack using a secondary battery.

[0008]

The first invention of the present application for achieving the above object provides a secondary battery formed in a flat rectangular parallelepiped shape by accommodating a power generating element in an outer case formed of a laminate sheet. A plurality of battery packs are housed in a pack case, each of the pack cases comprises an upper case and a lower case formed in a half-shell formed of a flat plate portion and a side peripheral wall. case and the position restricting wall for restricting the accommodation position of the secondary battery surrounds the four sides of each of the plurality of secondary batteries in the lower case, each flat
The upper case is formed so as to project from the plate portion , and the upper case is joined to the lower case accommodating the plurality of secondary batteries between the position regulating wall and the side peripheral wall so that both cases are integrated. It is characterized by

[0009] According to this arrangement, the four sides of the secondary battery formed in flat rectangular parallelepiped shape is surrounded by a position restricting wall, not even move the secondary battery when joined by shock or vibration, the laminate It is possible to prevent the occurrence of defects due to the movement of the secondary battery having the sheet as the outer case in the pack case. In addition, the position control wall and side wall that partition the inside of the pack case
Since the upper case and the lower case are joined to the wall,
The rigidity of the pond pack can be increased.

Further, a second invention of the present application is the structure of the first invention.
In addition to the above , place it on the flat part of the upper case and / or the lower case.
Those that have a plurality of secondary batteries surface in contact with the respective flat surface, characterized in that it is formed on the elastic deformation surface that elastically deforms in response to the thickness change of the secondary battery are thinner form than its surroundings is there.

According to this structure, each secondary battery formed in the shape of a flat rectangular parallelepiped is housed in the pack case with its four sides surrounded by the position regulating walls and the flat plate surface surrounded by the elastically deformable surface. The position does not move even when vibration or vibration is applied. Moreover, since the upper case and the lower case are joined between the position regulation wall and the side peripheral wall that partition the inside of the pack case, the rigidity of the battery pack can be increased. In addition, the elastically deforming surface contacts the flat surface of the secondary battery to suppress expansion of the electrode plate, and when expansion occurs in the electrode plate, the thickness changes at the surface, which causes abnormal deformation of the outer shape of the pack case. The device to which the battery pack is attached is not adversely affected.

In the above structure, the position control wall and the side peripheral wall facing each other between the upper case and the lower case are formed with a concave portion on one side and a convex portion fitted into the concave portion on the other side, respectively. The positioning and fitting between the lower case and the lower case becomes reliable, and the rigidity of the battery pack can be further increased.

Further, a V-shaped cross section is formed on the bottom surface of the recess.
By forming a V-shaped groove, a V-shaped rib having a V-shaped cross-section that fits in the V-shaped groove is formed at the tip of the convex portion, and ultrasonic bonding is performed between the V-shaped groove and the V-shaped rib. The ultrasonic bonding portion is formed at the bottom of the recess, the bonding portion is not exposed to the outside, and the ultrasonic bonding can be performed while maintaining the fitted state between the upper case and the lower case. When stress is applied to the joints of the upper and lower cases due to shocks such as dropping, the convex parts are deformed with priority, and this deformation is retained in the concave parts, so the influence on the secondary battery whose position is regulated by the peripheral wall Is reduced. Further, since the resin melted at the time of welding is fixed on the bottom surface of the recess, the molten resin does not drip from the joint portion and adhere to the secondary battery.

By attaching a thin metal plate to the outer surface of the elastically deformable surface, the secondary battery is prevented from being damaged when the thin elastically deformable surface is pierced by a knife or the like. it can.

Further, by forming the height of the battery housing space between the upper case and the lower case to be smaller than the thickness of the secondary battery, the state in which the tension is applied to the secondary battery is strengthened,
The effect of suppressing the expansion of the electrode plate can be improved, and the retention of the secondary battery is further strengthened.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiments described below are examples of embodying the present invention and do not limit the technical scope of the present invention.

The embodiment of the present invention shows a structure of a battery pack in which three secondary batteries 1 containing a power generating element are connected in parallel in an outer case formed of a laminate sheet. As shown in FIG. 1A, the three secondary batteries 1 and the circuit board 3 are housed in the lower case 2b that constitutes the pack case 2, and the upper case 2a is joined to the lower case 2b. As shown in the external view, it is formed into a flat secondary battery pack.

The secondary battery 1 is constructed as a lithium polymer secondary battery, and a laminate sheet in which both surfaces of a metal layer are covered with a plurality of resin layers is folded in two, and the secondary sheet shown in FIG.
As shown in (b), the power generation element is housed in the recess 29 formed on the one surface side of the laminate sheet to be folded in two,
As shown in FIG. 2A, the three seal sides P1, P2,
The P3 is heat-sealed to form the outer case 4, and the positive electrode lead 11 connected to the positive electrode plate and the negative electrode lead 12 connected to the negative electrode plate of the laminated electrode plate 30 constituting the power generation element are connected to the outer case 4. It is drawn out from the same seal side P3. Seal sides P1 on both sides forming the outer case 4,
As shown in FIG. 2C, the P2 is bent and fixed on the flat plate surface with the adhesive tape 31 to reduce the width dimension.

As shown in FIG. 3, the secondary battery 1 is arranged in a lower case 2b formed into a half shell by resin molding. As shown in the figure, the lower case 2b is provided with battery positioning ribs 6a, 6b, 6c for individually positioning the plurality of secondary batteries 1, and surrounds each secondary battery 1 together with the inner peripheral wall 28 of the lower case 2b. The secondary battery 1 is positioned and held by its four sides, which constitutes a position restriction wall for restricting the accommodation position. The positive input / output terminal 25a, the negative input / output terminal 25b, the temperature detection terminal 2 are provided on the bottom surface of the lower case 2b.
An external input / output terminal 25 composed of 5c is attached to each of the positive lead plate 22a and the negative lead plate 22.
b, the lead plate 22 including the temperature detecting lead plate 22c is joined, and one end of each is located below the position where the circuit board 3 is disposed. The circuit board 3 includes board positioning ribs 7a, 7
b and the inner peripheral wall 28, the lower case 2b is positioned.
When the circuit board 3 is placed on the upper side, the positive connection terminals 20a, the negative connection terminals 20b formed on the circuit board 3,
Since the lead plates 22 corresponding to the respective holes of the connection terminals 20 composed of the temperature detection connection terminals 20c are respectively inserted, the lead plates 22 and the connection terminals 20 are soldered to be connected to each other, and the circuit board 3 is connected to the external input / output terminal. The state of being connected to 25 is obtained. With this connection configuration, the external input / output terminal 25
The secondary battery 1 can be charged and discharged through the circuit board 3.

As shown in FIG. 4, when the three secondary batteries 1 are positioned and arranged on the lower case 2b on which the circuit board 3 is arranged, the positive electrode lead 11 and the negative electrode lead 12 of each secondary battery 1 become , Its tip is located on the soldering land 21 formed on the circuit board 3. A connection member 19 formed of a nickel plate in advance is ultrasonically welded to the positive electrode lead 11 and the negative electrode lead 12, respectively, and the connection member 19 is connected to a soldering land 21 formed on the substrate 10 by a conductor pattern. By soldering, the three secondary batteries 1 are connected to the circuit board 3. The use of the connecting member 19 in this manner enables easy soldering because the positive electrode lead 11 is made of aluminum and cannot be soldered.

The circuit board 3 is formed as a double-sided board, and a conductor pattern 9 for connecting the soldering lands 21 and connecting the secondary batteries 1 in parallel is formed on the back surface. Connected by hole 13,
The circuit patterns of the overcurrent protection element 8 and the protection circuit 5 which constitute the battery protection device are formed.

By connecting each secondary battery 1 to the circuit board 3, as shown in the circuit diagram of FIG. 5, each secondary battery 1 is connected in parallel with the overcurrent protection element 8 connected in series. A circuit configuration is obtained in which three secondary batteries connected in parallel are connected to the connection terminal 20 through the protection circuit 5. The overcurrent protection element 8 prevents the secondary batteries 1 from being damaged by being blown out when an excessive charging / discharging current flows in each secondary battery 1. In addition, the protection circuit 5 is an IC
A plurality of electronic components including components are intensively mounted at a predetermined position on the substrate 10 and covered with a resin mold 26, and an abnormal state as a secondary battery pack such as overcharge or overdischarge is detected. When detected, the input / output circuit is shut off to protect the secondary battery 1 from an abnormal state. A battery protection device is configured by the overcurrent protection element 8 and the protection circuit 5, and prevents damage to the secondary battery due to failure or malfunction of the device connected to the secondary battery pack, or incorrect use. You can

After all the components are housed in the lower case 2b in this way, the upper case 2a is ultrasonically bonded to the lower case 2b as shown in FIG. 1 to pack a plurality of secondary batteries 1 in a pack case. The secondary battery pack enclosed in 2 is completed.
Below, the joint structure of the upper case 2a and the lower case 2b will be described.

As shown in FIG. 6, the upper casing 2a has side ribs 33 fitted into the side grooves 34 formed between the inner peripheral wall 28 and the outer peripheral wall 27 of the lower case 2b, and the lower case 2b.
A battery holding rib 36 that is fitted into the battery holding groove 35 between the battery positioning ribs 6b and 6b formed on the lower case 2b.
A lead side holding rib 37 fitted between the battery positioning rib 6a and the board positioning rib 7a formed in the above, and a board holding rib 38 for restricting the position of the circuit board 3 in the thickness direction are formed. In addition, positioning ribs 39 are formed at three corners, and the positioning portion 4 is formed on the lower case 2b.
It is configured so that it can be fitted to zero.

When the positioning rib 39 is inserted into the positioning portion 40 of the lower case 2b to position the upper case 2a on the lower case 2b and the upper case 2a is pressed to the lower case 2b side, as shown in FIG. The circumferential rib 33 is in the side circumferential groove 34, the battery holding rib 36 is in the battery holding groove 35 as shown in FIG.
The lead side holding ribs 37 are fitted between the battery positioning ribs 6a and the substrate positioning ribs 7a, and the V-shaped ribs 42 formed at the respective rib tips are V-shaped grooves 43 formed at the bottoms of the grooves.
Fit in. In this state, the upper case 2a and the lower case 2b
And are clamped by a horn and a receiving jig of the ultrasonic welding device, and ultrasonically excited from the horn, the upper case 2a and the lower case 2b are welded between the V-shaped rib 42 and the V-shaped groove 43. . In this way, by fitting the upper case 2a and the lower case 2b in a structure in which the convex portions fit in the concave portions, reliable positioning can be performed and at the same time the rigidity of the pack case 2 can be increased. Further, by ultrasonically bonding the tip of the convex portion at the bottom of the concave portion, the joint portion is not exposed to the outside,
Since this is performed not only in the peripheral portion but also in the position surrounding the plurality of secondary batteries 1, the strength of the pack case 2 against twisting and bending can be improved. Further, when stress is applied to the joint between the upper and lower cases 2a and 2b due to an impact such as a drop, the concave portion is preferentially deformed, and this deformation is held in the concave portion, so that the secondary battery 1 is not affected. Will be reduced.
Further, since the melted resin is fixed at the bottom of the recess during welding, the melted resin does not drip from the joint surface and adhere to the secondary battery 1.

FIG. 9 shows a state in which the secondary battery 1 is accommodated in the pack case 2. FIG. 9A is a lateral direction of the secondary battery 1, and FIG. 9B is a longitudinal direction of the secondary battery 1. FIG. As shown in the figure, the portion of the lower case 2b that comes into contact with the flat plate surface of the secondary battery 1 is formed as a thin-walled elastically deforming surface 44. FIG. 10 is a plan view of the outer surface side of the lower case 2b, showing a state where the elastically deformable surface 44 is formed. The elastic deformation surface 44 is thinly formed at a position lower by the 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. Since the elastically deformable surface 44 is thin-walled, a stainless thin plate 45 is attached to prevent the secondary battery 1 from being damaged by being pierced by a blade or the like. This stainless steel thin plate 45 has protrusions 45a formed at its corners to facilitate positioning at the time of sticking, and is provided with a portion not covering the elastic deformation surface 44 on four sides to elastically deform the elastic deformation surface 44. The deformation of the part is not hindered. Incidentally, the secondary battery 1 arranged at the position where the external input / output terminal 25 is provided is provided with a thin-walled elastically deforming groove 46, and similarly, it is possible to cope with the thickness change of the secondary battery 1. I am trying.

When the electrode plate expands due to repeated charging / discharging or aging, when the outer case 4 is made of a soft material such as a laminate sheet like the secondary battery 1, the secondary battery 1 The average thickness increases, pushing up the elastically deforming surface 44. Since the elastically deformable surface 44 is deformed at the peripheral portion thereof, the central portion of the elastically deformable surface 44 is kept flat and rises in the step H. Therefore, by setting the step H corresponding to the amount of change in the thickness of the secondary battery 1, the thickness of the secondary battery 1 does not change and the thickness of the battery pack does not change. It does not affect the equipment to be used.

Further, as shown in FIG. 9A, when the secondary battery 1 is housed in the pack case 2, a bulging portion 47 is formed in the longitudinal direction of the secondary battery 1 on the inner surface of the upper case 2a. ,
The secondary battery 1 is sandwiched between the elastic deformation surface 44. Since the elastic deformation surface 44 applies a force in the compression direction to the secondary battery 1 due to its elasticity, the secondary battery 1 is always subjected to a tensioning force to suppress the expansion of the electrode plate. Further, the secondary battery 1 in which the outer case 4 is formed of a soft material such as a laminated sheet
Is weak in the force of restraining the laminated electrode plates, and the laminated electrode plates are likely to be displaced when shock or vibration is applied, but the side faces are surrounded by four sides and the thickness direction is reduced. The movement of the electrode plate is restricted by the application of the tense force.

The configuration of the embodiment described above is a case where three secondary batteries 1 are housed in the pack case 2.
The same configuration can be applied to the case of three or less and three or more.

[0030]

As described above, according to the present invention, since a plurality of secondary batteries are individually housed in a space surrounded by a wall, the secondary battery is easily damaged by using a laminate sheet as an outer case. Is reliably held in place, and the elastically deformable surface can cope with the expansion of the electrode plate. In addition, since the upper case and the lower case are joined not only to the side peripheral wall but also to the wall surrounding the secondary battery, it is possible to sufficiently obtain the twisting strength and the bending strength of the thin battery pack.

[Brief description of drawings]

FIG. 1A is an external view of a secondary battery pack according to an embodiment, and FIG. 1B is a perspective view with a pack case opened.

2A is a plan view showing a sealed state of an outer case, FIG. 2B is a side view, and FIG. 2C is a plan view showing a completed state of the secondary battery.

FIG. 3 is a plan view showing a configuration of a lower case.

FIG. 4 is a plan view showing a state in which a circuit board and a secondary battery are housed on a lower case.

FIG. 5 is a circuit diagram showing electrical connection of a secondary battery pack.

FIG. 6 is a plan view showing the configuration of the inner surface side of the upper case.

FIG. 7 is a cross-sectional view showing a fitted state in the peripheral portion of the upper case and the lower case.

FIG. 8 is a cross-sectional view showing a fitted state between batteries in an upper case and a lower case.

9A and 9B are cross-sectional views showing a state in which the secondary battery is accommodated in the pack case, wherein FIG.

FIG. 10 is a plan view showing a configuration of an outer surface side of a lower case.

[Explanation of symbols]

1 secondary battery 2 pack case 2a upper case 2b lower case 4 exterior case 6 Battery positioning rib (position control wall) 27 Outer peripheral wall (side peripheral wall) 28 Inner peripheral wall (side peripheral wall) 33 Side peripheral rib (side peripheral wall) 34 Side groove (recess) 35 Battery holding groove (recess) 36 Battery holding rib (position control wall)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Aoki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 2000-148297 (JP, A) JP 11-45691 (JP, A) JP 2000-48785 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 2/00-2/08 H01M 2/10 H01M 2/20-2 / 34 H01M 10/40

Claims (6)

(57) [Claims] 1. A battery pack comprising a plurality of secondary batteries formed in a flat rectangular parallelepiped shape in which a power generating element is housed in an outer case formed of a laminate sheet, Each of the pack cases includes a flat plate portion and a side peripheral wall.
The upper case and the lower case, which are formed in a configured half-shell, are provided with a position regulating wall that regulates the accommodating position of the secondary battery by enclosing the four sides of each of the plurality of secondary batteries in the upper case and the lower case. , The upper case is formed so as to project from each flat plate portion , and the upper case is joined between the position regulating wall and the side peripheral wall to the lower case accommodating a plurality of secondary batteries so that both cases are integrated. A battery pack that is characterized by being manufactured. The flat plate portion of wherein Ueke over scan and / or lower case
The surface in contact with the flat plate surface of each of the plurality of secondary batteries in the
The battery pack according to claim 1, wherein the battery pack is thinner than its surroundings and is formed on an elastically deformable surface that elastically deforms in response to a change in thickness of the secondary battery. 3. A position facing between the upper case and the lower case.
置規system wall and side wall, a concave portion on one side facing the convex portion that fits into the recess on the other side is formed according to claim 1 or
The battery pack described in 2 . 4. A V-shaped groove having a V-shaped cross-section is formed on the bottom surface of the recess, and a V-shaped rib having a V-shaped cross-section that fits into the V-shaped groove is formed at the tip of the protrusion. claims between the V-shaped grooves and V-shaped ribs formed by configured to be ultrasonically bonded 3
Battery pack described. 5. The battery pack according to claim 2, wherein a thin metal plate is attached to the outer surface of the elastically deformable surface. 6. The battery pack according to claim 1, wherein the height of the battery housing space between the upper case and the lower case is smaller than the thickness of the secondary battery.