JP2009104888A - Protection module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection module in which a volume to protect charge and discharge of a secondary battery is small. <P>SOLUTION: In the protection module which has a battery connecting terminal 4B and a connecting terminal 8 to a load in a wiring board surface 2 having wiring in a single layer or multiple layers, at least either one of electronic parts 9, 11, 10 constituting a battery protection circuit is mounted and arranged in recessed parts 12A, 12B formed in the wiring board surface 2, and a flat plate-like semiconductor element constituting the protection circuit is flip-chip mounted on a parts mounting surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a protection module in which a protection circuit device capable of controlling charge and discharge such as overcharge, overdischarge, and overcurrent of a secondary battery is attached to a battery or an object to be attached to the battery.

  The reduction in size and weight of portable battery-powered devices such as mobile phones is advancing further, and the size of secondary batteries used in devices is also required to be reduced. Along with this, protection modules built into secondary batteries or provided on the battery equipment side are also required to be downsized, and bare chips are mounted on an insulating substrate from those using package-type discrete semiconductor elements. A COB (Chip on Board) structure that seals the whole with resin after wire bonding wiring, CSP (Chip Size Package) that has become more compact and no longer requires wire bonding space, and a metal for connection on the circuit surface of the chip Many of these are arranged and mounted by flip chip mounting which is electrically connected by pressing the circuit surface downward against the substrate.

  On the other hand, the conventional secondary battery protection module 1 has a single-layer or multi-layer wiring 3 as shown in a perspective view in FIG. 11A and a cross-sectional view cut in a vertical direction in FIG. A connection terminal 4A to the positive electrode of the secondary battery, a connection terminal 4B to the negative electrode of the secondary battery, a connection terminal 5 to the positive electrode of the battery using device or the charger, a temperature detection signal terminal 6 of the secondary battery, A battery state detection element 9 having a device connection terminal 8 comprising a connection terminal 7 for connecting to a battery-use device or a negative electrode of a charger, and having an overcharge, overdischarge, overcurrent detection function and the like on the upper surface, and a charge / discharge control element 10 and these elements and a passive element 11 such as a capacitor and a resistor constituting a protection circuit are arranged.

  In addition, the battery state detection element 9 having an overcharge, overdischarge, overcurrent detection function and the like is a small and thin element made of CSP (Chip Size Package). In order to turn on and off a large current, a power transistor such as an FET is used.

  These semiconductor elements 9 and 10 use a CSP (Chip Size Package) or the like in which a BGA (Ball Grid Array) structure is flip-chip mounted. However, the passive element 11 having a thickness larger than that of the semiconductor element is used. The components are mounted on the same plane, and between each component, a wiring for connecting them and a space between the components are necessary to insulate them. For this reason, there was a limit to miniaturization.

In addition, a three-dimensional structure has been proposed in which elements that constitute a protection circuit are mounted on both surfaces of the insulating case and the lid of the concave structure, and the protection circuit components are incorporated inside the case by combining the two. (For example, Patent Document 1), a package-type discrete semiconductor element is mounted and two cases are stacked, and although a three-dimensional structure is realized, there is a limit to downsizing. As described above, the conventional secondary battery protection circuit module has a problem that it is difficult to reduce the size.
JP 2006-4783 A

  It is an object of the present invention to provide a small battery protection module having a small thickness and a small volume corresponding to a battery using device which is becoming smaller and lighter.

The present invention has a battery connection terminal and a device connection terminal on a wiring board surface wired in a single layer or multiple layers, and at least one of the electronic components constituting the battery protection circuit is a recess formed on the wiring board surface. The plate-like semiconductor element that is mounted and arranged and constitutes the protection circuit is a protection module that is flip-chip mounted on the component mounting surface.
It is the above-mentioned protection module having electronic parts constituting a battery connection terminal and a battery protection circuit on one main surface of the wiring board surface and having an apparatus connection terminal on the other main surface.
It is the above-mentioned protection module having a device connection terminal and a battery connection terminal on one main surface of the wiring board surface, and a mounting surface for electronic components constituting a battery protection circuit on the other main surface.
In the above-described protection module, an electronic component constituting the protection circuit device mounted in the recess is sealed with an insulating material to form an embedded structure.
This is the protective module in which all the mounted components are sealed with an insulating material.

In the present invention, by embedding at least a part of the component mounted on the protection module in the recess of the wiring board, wiring of the embedded component and the component mounted on the surface can be routed from the recess through the inner layer of the substrate, and all the components are the same. By removing the wiring space provided between the components when mounted on a flat surface, the space for wiring can be reduced. Further, the module thickness can be reduced by embedding the component in the concave portion of the substrate.
Furthermore, since it has a three-dimensional mounting structure, it is possible to secure a large distance for insulation between the embedded part and the non-embedded part, which is a two-dimensional plane compared to the case where the conventional insulation distance is ensured. The distance can be reduced. Further, by sealing the parts mounted in the recesses with an insulator, the insulation is further improved, and when the same insulation is required, the distance between the parts can be further reduced as compared with the structure without sealing.
By arranging the components to be mounted three-dimensionally as described above, high-density mounting is possible, and the protection module can be downsized.

  According to the present invention, in a battery protection module, at least one of the components mounted on the surface of the wiring board is disposed in a recess provided on the wiring board, thereby increasing the mounting density and reducing the size of the protection module. It has been found that it is possible to do.

The present invention will be described below with reference to the drawings.
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1A is a perspective view illustrating a protection module according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along a vertical plane.
The protection module 1 has battery connection terminals 4A and 4B on one main surface of a wiring board 2 on which a single-layer or multi-layer wiring 3 is formed, and the other main surface has a battery using device or a charger. It has a device connection terminal 8 comprising a connection terminal 5 with a positive electrode, a temperature detection signal terminal 6 of a secondary battery, and a connection terminal 7 with a battery-using device or a negative electrode of a charger.

In addition, a battery state detection element 9 having overcharge, overdischarge, overcurrent detection functions and the like and a charge / discharge control element 10 for connecting and disconnecting current are provided on the upper surface, depending on the state of the battery or the battery using device. To control the battery input / output current.
On the other hand, the passive elements 11 such as resistors and capacitors constituting the protection circuit are provided on the wiring board 2 and disposed in the recesses 12A and 12B.

  The battery state detection element 9 and the charge / discharge control element 10 are CSP (Chip Size Package) structure semiconductor elements. These elements are connected by flip-chip mounting by conductive connection between a connection metal portion coupled to the mounting surface of the wiring board 2 and the wiring 3 formed inside and the bumps on the element side.

  As these semiconductor elements, elements having a BGA (Ball Grid Array) structure connected by solder balls can be used. The solder ball has a diameter of about 0.1 to 0.3 mm, and the mounted element can have a total thickness of about 0.3 to 0.5 mm including the solder ball.

Therefore, when these passive elements are housed in the recesses, the thickness of the protection module can be reduced by housing the passive components in the recesses.
As the passive elements, those having a size of 1608, that is, 1.6 mm in length, 0.8 mm in width, 1005, that is, 1.0 mm in length, 0.5 mm in width, 0603, that is, 0.4 mm in length, and 0.2 mm in width. Although used, they generally have a thickness of 0.6 to 0.7 mm.

  Therefore, if a glass epoxy substrate having a thickness of about 1.0 to 1.5 mm is used as the wiring substrate and a depth of the recess is about 0.5 to 0.8 mm, the passive element disposed in the recess is a recess. Or slightly protrude from the recess.

In addition, since the elements of the CSP structure and the BGA structure are becoming thinner, these elements are mounted on the surface of the protection module by flip chip mounting, and only passive elements having a relatively large thickness are disposed in the recesses. It is possible to reduce the thickness of the module.
In FIG. 1B, the device connection terminal 8 and the battery connection terminals 4A and 4B are formed on different surfaces, but as shown in FIG. 1C, they may be formed on the same surface. good.

FIG. 2 is an exploded perspective view illustrating one embodiment for connecting the protection module of the present invention to a battery.
An example in which battery connection members 22A and 22B made of a connection TAB or the like having one end joined to a battery connection terminal (not shown) of the component mounting surface 21 of the protection module 1 are combined with the battery 20 to form a conductive connection with the battery 20. Is shown.
The connection to the battery is not limited to the connection using the connection TAB as described above, and a general lead wire having a circular cross-section can be joined. In this case, since the joining with the connection terminal can be realized with a small area, the size of the connection terminal provided in the protection module can be reduced.

  Also, in the example shown in the figure, the recess is formed by a bottom surface made of one plane and a wall surface made of a vertical plane around it, but the bottom surface is provided with a step for each component to be placed, By forming a pleated uneven surface on the vertical wall, and increasing the creepage distance in a limited space, the insulation distance can be increased.

3-5 is a figure explaining an example of the manufacturing process of the protection module of the 1st embodiment of this invention.
3A shows a perspective view, and FIG. 3B is a cross-sectional view cut along a vertical plane.
Concave portions 12A and 12B are formed on one main surface of the wiring board 2, and connection terminal wirings 14A and 14B and electronic components are mounted on the surface of the main surface and the bottom surface of the concave portion to provide battery connection terminals. Therefore, the electrode wirings 15 and 16 are formed, and on the other main surface, the connection terminal 5 to the positive electrode of the secondary battery using device or the charger, the temperature detection signal terminal 6 of the secondary battery, the negative electrode of the battery using device or the charger, A device connection terminal 8 comprising the connection terminals 7 is formed.

  Next, FIG. 4 (A) shows a perspective view, and FIG. 4 (B) shows a cross-sectional view cut along a vertical plane, so that protection is provided on the electrode wiring 16 in the recesses 12A and 13B of the wiring board 2. The passive element 11 constituting the circuit is mounted. Mounting can be performed by applying solder cream to the electrode wiring 16 part, mounting the passive element 11 thereon, and solder mounting by heating such as reflow.

Next, as shown in FIG. 5 which is a cross-sectional view cut along a vertical plane, the battery state detection element 9 having overcharge, overdischarge, overcurrent detection functions, etc. on the electrode wiring 15 of the substrate is a CSP structure semiconductor. The element is flip-chip mounted by applying solder cream to the electrode wiring 15 and heating such as reflow. Similarly, a power transistor such as an FET having a CSP structure as the charge / discharge control element 10 is also mounted by flip chip mounting.
Further, conductive members are arranged on the battery connection terminal wirings 14A and 14B and joined by soldering by heating such as reflow to produce the battery connection terminals 4A and 4B.
The protection module of the present invention can be manufactured through the above steps.
In the above description, an example in which terminals corresponding to both positive and negative electrodes are provided for both battery connection devices, battery connection devices and battery connection terminals, but either terminal is a common terminal. It is also good.

Next, a second embodiment of the present invention will be described with reference to the drawings.
6A and 6B are diagrams illustrating a protection module according to a second embodiment of the present invention. FIG. 6A shows a perspective view, and FIG. 6B shows a cross-sectional view cut along a vertical plane.
The protection module 1 shown in FIG. 6 has battery connection terminals 4A and 4B on the main surface on the upper surface side of the wiring board 2 on which the single-layer or multilayer wiring 3 is formed, and the other main surface has a battery connection terminal 4A. It has a device connection terminal 8 comprising a connection terminal 5 to the positive electrode of the device or charger used, a temperature detection signal terminal 6 of the secondary battery, and a connection terminal 7 to the negative device of the battery device or charger.

In addition, a battery state detection element 9 having overcharge, overdischarge, overcurrent detection functions and the like and a charge / discharge control element 10 for connecting and disconnecting current are provided on the upper surface, depending on the state of the battery or the battery using device. To control the battery input / output current.
On the other hand, the passive element 11 such as a resistor and a capacitor constituting the protection circuit is provided on the wiring board 2 and disposed in the recesses 12A and 12B. In the space between the wall surface of the recess and the passive element, an insulating material 17 is provided. Is filled. As the insulating substance, an insulating resin such as an epoxy resin, or a composition containing a prepreg containing an insulating resin and glass fiber or the like can be used.

As described above, since some of the components are disposed in the recesses provided in the wiring board and filled with the insulating material, it is possible to prevent a decrease in insulation performance due to a change in the surrounding environment. Also, if the same insulation performance is maintained compared to the case where no insulating resin is filled, the distance between components can be reduced, enabling high-density mounting, reducing the mounting area, and Can be downsized.
For example, in the protection module shown in FIG. 1, the battery state detection element 9, the charge / discharge control element 10, and the passive element are provided between the battery connection terminals 4A and 4B arranged on one main surface. Although there are recesses, the distance between these recesses can be reduced, so that the protection module can be reduced in size.

  As shown in FIG. 6, when the spaces on both sides of the two concave portions filled with the insulating material 17 are shortened by 0.5 mm, the total size can be reduced by 2 mm. Further, if the effect of reducing the thickness of 0.2 mm is obtained by arranging the passive element in the concave portion, in the case of a protection module having an outer shape of 20 mm in length, 3 mm in width, and 1.5 mm in thickness, The outer shape is 18 mm × 3 mm × 1.3 mm, and a reduction in size of 22% can be realized by volume ratio.

Below, the manufacturing method of the protection module of the 2nd embodiment of this invention is demonstrated.
FIG. 7 is a cross-sectional view taken along a vertical plane for explaining the protection module according to the second embodiment of the present invention.
As shown in FIG. 7A, recesses 12A and 12B are formed on one main surface of the wiring board 2, and electrode wirings 15 and 16 are mounted on the surface of the main surface and the bottom surface of the recess to mount electronic components. And connection terminal wirings 14A and 14B are formed to provide battery connection terminals. In addition, on the other main surface, a device connection terminal comprising a connection terminal 5 to the positive electrode of the battery using device or the charger, a temperature detection signal terminal 6 of the secondary battery, and a connection terminal 7 to the negative electrode of the battery using device or the charger. 8 is formed.

  Next, as shown in FIG. 7B, the passive element 11 constituting the protection circuit is mounted on the electrode wiring 16 in the recesses 12 </ b> A and 12 </ b> B of the insulating support substrate 1. Mounting can be performed by applying solder cream to the electrode wiring 16 part, mounting the passive element 11 thereon, and solder mounting by heating such as reflow.

Next, as shown in FIG. 7C, an insulating material 17 made of an insulating resin or the like is filled in the spaces of the recesses 12A and 12B.
Furthermore, as shown in FIG. 7D, as the battery state detection element 9 having overcharge, overdischarge, overcurrent detection functions, etc. on the electrode wiring 15 of the substrate, a CSP structure semiconductor element is formed by flip chip mounting. It is mounted, solder cream is applied to the electrode wiring 15 and mounted by heating such as reflow. Similarly, a power transistor such as an FET having a CSP structure is mounted as the charge / discharge control element 10 by flip chip mounting.
In addition, the protective module according to the second embodiment of the present invention can be obtained by arranging conductive members on the battery connection terminal wirings 14A and 14B and joining them by soldering by heating such as reflow to produce the connection terminals 4A and 4B. Can be produced.

Next, a protection module according to a third embodiment of the present invention will be described with reference to a sectional view taken along a vertical plane in FIG.
In the second embodiment, the example in which the passive element whose height is lower than the depth of the recess is arranged in the recess of the protection module provided on the first main surface, but in the third embodiment, the recess 12A is arranged. Even when the passive element 11 having a height higher than the depth of 12B is mounted, the surface of the passive element 11 and the insulating material are higher than the height H1 of the surface of the component disposed on the surface of the first main surface. The case where the surface of 17 becomes low is shown. By doing so, the size of the protection module can be reduced as in the first or second embodiment.

Next, a fourth embodiment of the present invention will be described.
FIG. 9 is a cross-sectional view taken along a vertical plane, and is a diagram illustrating a protection module according to a fourth embodiment of the present invention.
As shown in the perspective view of FIG. 9 (A), the protection module of the fourth embodiment includes components arranged on the first main surface of the protection module 1 shown in the first or second embodiment. The protective member 18 is covered. Various members can be used as the protective member 18 as long as they are insulating members. However, in the second embodiment, a composition containing an epoxy resin similar to the insulating material filled in the recesses should be used. Can do.

FIG. 9B is a cross-sectional view illustrating an example in which the protection module 1 according to the second embodiment is covered with the protection member 18.
Thus, when the components of the protection module 1 are covered with the protection member 18, the volume corresponding to at least the thickness of the protection member 18 is increased. However, in the protection module of the present invention, the protection member 18 is covered. Since the volume of the previous protection module can be reduced, the volume of the protection module 1 covered with the protection member 18 can be made smaller than that of the conventional protection module. The protection module 1 that is not easily affected can be provided.
For example, when the first main surface of the conventional protection module described in the second embodiment having a length of 20 mm, a width of 3 mm, and a thickness of 1.5 mm is sealed with a resin having a thickness of 0.2 mm Is 20 mm × 3 mm × 1.7 mm, but the outer shape described in the second embodiment is a case where the main surface of the protection module of 18 mm × 3 mm × 1.3 mm is sealed with a resin having a thickness of 0.2 mm The size is 18 mm × 3 mm × 1.5 mm, and the volume ratio can be reduced by 21%.

In the example shown above, the example in which the passive element is arranged in the recess is shown, but it is shown that it is possible to reduce the thickness of the protection module by arranging the passive element having a large thickness in the recess. Thus, it is not specified that only the passive element is disposed in the recess, and all components may be disposed in the recess.
FIG. 10 is a diagram for explaining the fifth embodiment of the present invention, and is a sectional view for explaining an example in which all of the passive elements and the semiconductor elements are arranged in the recesses.
FIG. 10 shows an example in which the passive element 11 having a large thickness is disposed in the recesses 12A and 12B, and the battery state detection element 9 and the charge / discharge control element 10 are disposed in the recesses 12C and 12D, respectively. Thus, when the semiconductor element is arranged in the recess, it is possible to improve the static electricity resistance of the external electric nozzle, particularly the semiconductor element that is easily affected by static electricity, and to provide a highly reliable protection module. Is possible.

  In the protection module of the present invention, by embedding at least a part of the component in the recess of the mounting substrate, wiring of the embedded component and the component mounted on the surface can be routed from the recess through the inner layer of the substrate. When mounted, the wiring space provided between the components can be removed and the space for wiring can be reduced, so that a protection module having a small volume can be provided.

FIG. 1 is a diagram illustrating a protection module according to the present invention. FIG. 2 is a diagram illustrating one embodiment of a battery equipped with the protection module of the present invention. FIG. 3 is a diagram for explaining a first embodiment of the protection module of the present invention. FIG. 4 is a diagram for explaining a manufacturing process of the protection module according to the first embodiment of the present invention. FIG. 5 is a diagram for explaining a manufacturing process of the protection module according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating the protection module according to the second embodiment of the present invention. FIG. 7 is a diagram for explaining a manufacturing process of the protection module according to the second embodiment of the present invention. FIG. 8 is a diagram for explaining the protection module according to the third embodiment of the present invention. FIG. 9 is a diagram illustrating a protection module according to a fourth embodiment of the present invention. FIG. 10 is a diagram for explaining the protection module according to the fifth embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a conventional protection module for a secondary battery.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Protection module, 3 ... Wiring, 2 ... Wiring board, 4A, 4B ... Battery connection terminal, 5 ... Connection terminal with battery use apparatus or the positive electrode of a charger, 6 ... Secondary battery temperature detection signal terminal, 7 ... Battery connection device or connection terminal with negative electrode of charger, 8 ... device connection terminal, 9 ... battery state detection element, 10 ... charge / discharge control element, 11 ... passive element, 12A, 12B, 12C, 12D ... recess, 14A, 14B ... Connection terminal wiring, 15, 16 ... Electrode wiring, H1 ... Part height, 17 ... Insulating material, 18 ... Protective member, 20 ... Battery, 21 ... Component mounting surface, 22A, 22B ... Battery connection Element

Claims (5)

At least one of the electronic components that have battery connection terminals and device connection terminals on the wiring board surface wired in a single layer or multiple layers and that constitute the battery protection circuit is mounted and disposed in a recess formed on the wiring board surface. The protection module is characterized in that the flat semiconductor element constituting the protection circuit is flip-chip mounted on a component mounting surface. The protection module according to claim 1, further comprising: an electronic component constituting a battery connection terminal and a battery protection circuit on one main surface of the wiring board surface, and an apparatus connection terminal on the other main surface. 2. The circuit board according to claim 1, further comprising: a device connection terminal and a battery connection terminal on one main surface of the wiring board surface, and a mounting surface for electronic components constituting a battery protection circuit on the other main surface. Protection module. The protection module according to any one of claims 1 to 3, wherein an electronic component constituting the protection circuit device mounted in the recess is sealed with an insulating material to form an embedded structure. 5. The protection module according to claim 1, wherein all the mounted components are sealed with an insulating material.

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