JP2002251986A - Connection structure for flat battery and protection circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure for a flat battery and a protection circuit board with high connection reliability. SOLUTION: In the connection structure, a positive electrode terminal 4 and a negative electrode terminal 5 of the flat battery and a positive electrode side land 23 and a negative electrode side land 24 of the protection circuit board are connected via intermediate tabs 25 and 26 with shapes capable of respectively absorbing tolerances of size in the longitudinal direction of the protection circuit board 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between a flat battery and a protection circuit board, and more particularly, to a connection between a flat battery and a protection circuit board due to a dimensional tolerance in the longitudinal width direction of the protection circuit board. And a connection structure in which the positive electrode terminal and the negative electrode terminal are prevented from being damaged.

[0002]

2. Description of the Related Art In recent years, as various electronic devices such as mobile phones and portable personal computers have been reduced in size and weight, battery characteristics such as higher energy density have been required for these driving power supplies. Demands for further miniaturization and weight reduction are increasing in addition to the improvement in the size. Above all, the demand for thinning is remarkable.

In order to meet such a demand, for example, L
In the case of an i-ion secondary battery, research on a flat battery using a polymer solid electrolyte film as an electrolyte is underway. This flat battery usually has a tongue-shaped positive electrode terminal integrally formed, for example, LiCoO _{2 on} one surface of an Al foil.
A positive electrode coated with a mixture mainly composed of, for example, and a tongue-shaped negative terminal are integrally formed, for example, Ni
Between one side of the foil and a negative electrode formed by applying a mixture containing a carbon material, for example, a polymer solid electrolyte film is arranged to form a power generating element, and both sides of the power generating element are covered with a positive electrode and a negative electrode. An exterior material having a large outer diameter, such as an Al laminated film, is disposed, and the power generating element is sealed by heat-sealing each peripheral portion of the exterior material. The thickness is usually about 3 to 4 mm.

Further, in actual use, measures have been taken to prevent the above-mentioned flat battery from being damaged by an external force by accommodating the flat battery in, for example, a plastic or metal protective casing. In this case, prior to being housed in the protective housing, a protective circuit board on which predetermined protective circuit components are surface-mounted in order to protect the battery by monitoring the battery temperature during actual use and controlling the charge / discharge current. Is connected to this flat battery to assemble the two integrated structures. Then, the integrated structure is housed in a protective housing and shipped as a battery pack.

FIGS. 3 and 4 show a conventional example of a connection structure between a flat battery and a protection circuit board. That is, in the flat battery 1, the power generation element 2 is covered with an exterior material, for example, an Al laminated film 3, and a peripheral sealing portion of the film 3 is heat-sealed. Furthermore, in order to further reduce the size of the flat battery 1, of the peripheral sealing portions, the peripheral sealing portion 3 from which the positive electrode and the negative electrode terminal protrude.
The edge 3a excluding a 'is bent by about 90 degrees as shown. Therefore, the end face 2a of the power generation element 2, the bent edges 3a, 3a on both sides thereof, and the unfolded edge 3
a ′ forms a shelf-shaped space 10.

The positive terminal 4 and the negative terminal 5 extending from the power generating element respectively protrude from one end of the peripheral sealing portion 3a '. The positive electrode terminal 4 is usually made of, for example, Al, and the negative electrode terminal 5 is usually made of, for example, Cu. On the other hand, on the surface of the protection circuit board 6, the protection circuit components 7
Are mounted by, for example, a reflow process using solder, and further, on both sides of the protection circuit component 7, a positive electrode side land 8 and a negative electrode side land 9 connected to the positive electrode terminal 4 and the negative electrode terminal 5 of the flat battery 1, respectively. Are formed.
The lands 8, 9 are generally formed of Cu.

When the flat battery 1 and the protection circuit board 6 are connected, first, the positive terminal 4 of the flat battery 1 and the positive land 8 of the protection circuit board 6 are connected by spot welding, for example. Then, the negative electrode terminal 5 and the negative electrode side land 9 are connected by, for example, spot welding. further,
As shown in FIG. 4, the positive and negative terminals 4, 5 of the flat battery 1 connected to the lands 8, 9 of the protection circuit board 6 are bent toward the power generation element 2, and the protection circuit board 6 is placed in the space 10. Housed in Thereby, it is possible to manufacture a very compact integrated structure 11 of the protection circuit board 6 and the flat battery 1.

[0008]

Conventionally, the connection between the positive and negative terminals 4, 5 of the flat battery 1 and the lands 8, 9 of the protection circuit board 6 has been manually performed. Recently, automation for mass production of the flat battery 1 has been promoted, but the following problems have arisen with the automation.

That is, when welding connection is performed manually, even when the terminals 4, 5 and the lands 8, 9 are relatively misaligned, respectively, the positions thereof are relatively accurately determined. I was able to make adjustments. However, when the vehicle is put on an automation line, the above-described positional deviation is not automatically corrected, so that the positioning is not performed as accurately as a manual operation, and the connection positions between the terminals 4 and 5 and the lands 8 and 9 are not adjusted. However, the connection operation may be completed in a state where the connection operation is slightly shifted in the longitudinal width direction of the protection circuit board 6.

When the protection circuit board 6 is accommodated in the space 10 shown in FIG. 4 by bending the terminals 4 and 5 as described above, the side end face 6 of the protection circuit board 6
a, 6b and the peripheral edge portion 3a of the Al laminated film cannot maintain an appropriate clearance. In an extreme case, the side end surface 6a or 6b of the protection circuit board 6 is
(1) It comes into contact with the periphery 3a of the laminated film.

Further, the integrated structure of the flat battery 1 and the protection circuit board 6 as described above is housed in a protection housing and is practically used as a battery pack. As a result, there is a possibility that damage occurs to the peripheral portion 3a of the Al laminated film, and damage is transferred from the damaged portion to the power generation element. When the connection position is shifted, a force in the width direction (direction indicated by an arrow in FIG. 4) is constantly applied to the positive and negative terminals 4 and 5. Since the positive electrode and negative electrode terminals 4 and 5 are thin members having a thickness of, for example, about 100 μm, by receiving such force constantly, the terminals 4 and 5 may be damaged at the boundary 4 a or 5 a with the peripheral edge 3 a ′ of the Al laminated film. Get damaged.

In any case, it is inevitable that the connection state as described above adversely affects battery performance and battery life. An object of the present invention is to solve the above-mentioned problems and to provide a connection structure between a flat battery and a protection circuit board with high connection reliability.

[0013]

In order to achieve the above object, according to the present invention, a positive terminal and a negative terminal of a flat battery and a positive land and a negative land of a protection circuit board are connected to the protection circuit. Provided is a connection structure of a flat battery and a protection circuit board, which are connected to each other via an intermediate tab having a shape capable of absorbing a dimensional tolerance in a longitudinal width direction of the board.

In the above configuration, the intermediate tab is preferably formed of Ni or Ni clad steel.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A connection structure between a flat battery and a protection circuit board according to the present invention will be described below with reference to the drawings. In the drawing, the same components as those in FIG. 3 are denoted by the same reference numerals. In the connection structure between the flat battery and the protection circuit board according to the present invention, as shown in FIG.
The protection circuit component 22 is mounted on the surface of the first component. Positive side lands 23 are provided on both sides of the protection circuit component 22, respectively.
A negative land 24 is formed. This land 23,
Reference numeral 24 denotes a portion to which one end of an intermediate tab described later is welded, and is preferably formed of, for example, pure Ni or Ni-clad steel having a thickness of about 200 to 500 μm.

The dimensions of the lands 23 and 24 are determined according to the shape and dimensions of the flat battery and the protection circuit board, but are usually preferably 3 mm or more both vertically and horizontally. The lands 23 and 24 are formed on the protection circuit board 21 by, for example, a reflow process. Intermediate tabs 25 and 26, which are intermediate members for connecting the lands 23 and 24 of the protection circuit board 21 and the positive and negative terminals 4 and 5 of the flat battery, respectively, are attached to the protection circuit board 21 when they are attached. It is necessary that the protective circuit board 21 be a member that can be deformed by a minute movement in the longitudinal width direction.

More specifically, as shown in FIG. 1, for example, a strip-shaped metal piece bent at two locations is used. In other words, of the respective portions of the intermediate tabs 25 and 26, the surfaces of the ends 25a and 26a facing the lands 23 and 24 of the protection circuit board 21 form land connection portions, and face the positive and negative terminals 4 and 5. Ends 25b, 26b
Form a terminal connection part. Further, the intermediate portions 25c and 26c connecting these connection portions are portions that share the deformation of the intermediate tab in the longitudinal width direction of the protection circuit board.

The material for forming the intermediate tabs 25 and 26 is preferably pure Ni or Ni clad steel. The size is preferably determined by the shape and size of the integrated structure with the flat battery and the protection circuit board, and the thickness is preferably, for example, about 100 to 200 μm. When assembling the integrated structure of the flat battery 1 and the protection circuit board 21 using the intermediate tabs 25 and 26 as described above, first, the other end 25 of the intermediate tabs 25 and 26 is used.
b and 26b are connected to the positive and negative terminals 4 and 5, respectively, of the flat battery to form the other land connection. Thereafter, the lands 23, 24 of the protection circuit board 21 and the ends 25a, 26a of the intermediate tabs 25, 26 are connected, for example, by spot welding to form one land connection.

At this time, the connection between the positive electrode terminal 4 and the corresponding end portion 25b of the intermediate tab 25 is preferably performed by, for example, ultrasonic welding, and the connection between the negative electrode terminal 5 and the corresponding intermediate tab 2 is preferably performed.
6 can be connected to the end 26b by, for example, ultrasonic welding or spot welding. After connecting the protection circuit board 21 and the positive and negative terminals 4 and 5 of the flat battery through the intermediate tabs 25 and 26 in this manner, the positive and negative terminals 4 and 5 are connected in the same manner as shown in FIG. Is folded toward the power generation element 2 to house the protection circuit board 21 in the space 10 formed on the front surface 2a of the power generation element 2 to form an integrated structure 30 of the flat battery and the protection circuit board. FIG. 2 schematically shows a state in which the protection circuit board 21 is accommodated in the space 10, and the intermediate tab 25,
The intermediate portions 25c, 26c of 26 can be slightly deformed in the longitudinal width direction of the protection circuit board 21, that is, in the direction indicated by the arrow in the figure.

Therefore, when assembling the integrated structure 30 of the flat battery 1 and the protection circuit board 21 by an automation line, if there is a slight dimensional tolerance deviation in the interval between the positive electrode and the negative electrode terminals 4 and 5, The lands 23, 24 of the protection circuit board 21 and the ends 25a, 2 of the intermediate tabs 25, 26
6a, or when the positions of the ends 25b, 26b of the intermediate tabs 25, 26 and the positive and negative terminals 4, 5 are slightly different, the space 10 After being stored in the middle tab 25,
26 is deformed and moved leftward or rightward in the drawing so as to absorb this shift, and is appropriately positioned between the end surfaces 21a, 21b of the protection circuit board 21 and the peripheral edge 3a of the Al laminated film. A good clearance can be maintained.

As a result, it is effective that excessive force is applied to the positive and negative terminals 4 and 5 of the flat battery 1 at the boundaries 4a and 5a between the outer peripheral portion 3a 'and the aluminum laminate film 3a'. Is prevented. Further, it is possible to prevent the end face 21a or 21b of the protection circuit board 21 from constantly abutting against the peripheral edge portion 3a of the Al laminated film due to the above-described dimensional tolerance or misalignment at the time of alignment, thereby preventing damage to the portion. it can. In addition, the integrated structure 30
When the power supply is incorporated as a driving power source, the above-described intermediate tabs 25 and 26 absorb vibrations and shocks, so that the battery life can be effectively improved.

[0022]

As described above, according to the connection structure of the flat battery and the protection circuit board of the present invention, the dimensional tolerance of the mounting position of the positive electrode and the negative electrode terminal, which has already occurred at the time of assembling the flat battery, and the protection circuit The intermediate tab can absorb the misalignment of the substrate and the positive and negative terminals during welding, so that damage to the peripheral sealing portion of the flat battery is prevented and the reliability of the battery is reduced. Its industrial value is great because its properties are greatly improved.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing an embodiment of a connection structure between a flat battery and a protection circuit board according to the present invention.

FIG. 2 is a conceptual diagram of an integrated structure of a flat battery and a protection circuit board according to the present invention as viewed from the protection circuit board side.

FIG. 3 is a partially exploded perspective view showing a conventional connection structure between a flat battery and a protection circuit board.

FIG. 4 is a partial perspective view of a conventional integrated structure of a flat battery and a protection circuit board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Flat battery 2 Power generation element 3 Insulation sealing part (Al laminated film) 4 Positive electrode terminal 5 Negative terminal 21 Protective circuit board 22 Protective circuit component 23,24 Land 25,26 Intermediate tab 25a, 26a One end of intermediate tab 25b , 26b The other end of the intermediate tab 25c, 26c The intermediate part of the intermediate tab 30 Integrated structure

Claims (2)

[Claims] A positive terminal and a negative terminal of the flat battery;
The positive land and the negative land of the protection circuit board are
A connection structure between a flat battery and a protection circuit board, wherein the flat battery and the protection circuit board are connected to each other via an intermediate tab having a shape capable of absorbing a dimensional tolerance in a longitudinal width direction of the protection circuit board. 2. The connection structure according to claim 1, wherein the intermediate tab is made of Ni or Ni-clad steel.