JP2002184369A - Live part protection case - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a protection case having a function of protecting a live part when an electrolyte leaks from a battery. SOLUTION: In a protective case 10 such as a battery pack for storing a lithium ion battery which is a secondary battery for charging and discharging and a printed wiring board 40 on which an electric circuit is mounted, one surface of the printed wiring board 40 is provided. An electric circuit is formed, and a silk print layer 60 is formed on the back of the surface having the electric circuit.
The outer periphery of the printed wiring board 40 on which is formed is covered with a low molecular force resin 70 to form a protective wall substrate, and the silk printed layer 60 faces the battery side to partition the live part of the electric circuit and the battery. Here, the partition is provided inside the protective case 10 with walls 11, 12, 1.
A groove is formed by using the grooves 3 and 14, the protective wall substrate is inserted into the groove, and a resin 80 such as a silyl group-containing special polymer is injected into the gap between the grooves to seal the groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective case for protecting live parts such as electric circuits and electronic circuits. In particular, the present invention relates to a protective case such as a battery case having a function of protecting a live part when an electrolyte leaks from a battery.

[0002]

2. Description of the Related Art In recent years, with the spread of portable cordless devices such as video cameras and notebook personal computers, demands for batteries used for such power sources have been increasing. In particular, small
There is an increasing demand for secondary batteries that are lightweight, have high energy density, and can be repeatedly charged and discharged. It is also often practiced to arrange a printed wiring board or the like close to a battery in a battery case and form an electric circuit such as a digital circuit or a control circuit thereon.

[0003] On the other hand, it is known that an electrolyte solution leaks from these secondary batteries, and the leaked electrolyte solution may cause failure of equipment equipped with the battery. In order to avoid such a failure, the battery case is divided into a battery room for storing the battery and a board room for storing the printed wiring board, and the battery and the printed wiring board are separated.

[0004] In order to protect the electric circuit on the printed wiring board from the leaked electrolytic solution, a partition wall portion is provided, and the partition wall is formed of resin. At this time, it is conceivable to use a silicon resin or the like as the resin and fill the resin between the battery and the printed wiring board.

[0005]

However, in order to separate the printed circuit board on which the electric circuit is mounted from the leaked electrolytic solution into the battery chamber and the board chamber, it is necessary to provide a partition in the battery pack. There is a problem that the battery pack becomes large.

Further, even if a partition wall for separating the battery chamber and the substrate chamber is formed by a resin wall, a gap is generated in an electrode portion,
There is a problem that immersion of the electrolytic solution due to the capillary phenomenon cannot be prevented.

In the structure in which the partition is filled with a resin such as silicone rubber to seal the conductor connecting the battery and the printed wiring board, the silicone resin is dissolved by the electrolyte and the sealing structure is broken. There is.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a protective case having a function of protecting a live part when an electrolyte leaks from a battery. It is.

[0009]

According to a first aspect of the present invention, there is provided a protective case for storing a battery and a substrate on which an electric circuit is formed, wherein the substrate is provided on one surface of the substrate. The formed electric circuit, and a silk print layer formed on the back surface of the substrate having the electric circuit,
It is configured to be a protective wall substrate having the electric circuit and a layer of low molecular force resin covering the outer periphery of the substrate on which the silk print layer is formed.

In a second aspect based on the first aspect, the low molecular weight resin is made of a fluororesin.

In a third aspect based on the first aspect, the protective wall substrate is disposed on an inner surface of the protective case such that a surface having the silk print layer faces the battery to be stored. , Configured to be fixed.

In a fourth aspect based on the third aspect, the protection case is configured to have a groove for inserting a periphery of the protection wall substrate therein.

In a fifth aspect based on the fourth aspect, the protective wall substrate is inserted into a groove inside the protective case and fixed using an adhesive made of a special polymer containing a silyl group. The stored battery is configured to be sealed in the protective case.

In a sixth aspect based on the fifth aspect, the silyl group-containing special polymer is obtained by mixing a silicone resin and an acrylic resin.

According to a seventh aspect of the present invention, in a protective case having a substrate having an electric circuit formed thereon, the substrate has an electric circuit formed on one surface of the substrate and the electric circuit of the substrate. A protective wall substrate having a silk print layer formed on the back side of a surface, and a layer of low molecular force resin covering the outer periphery of the substrate on which the electric circuit and the silk print layer are formed, wherein the protective wall substrate is One surface of the protection case is formed, and the surface on which the silk print layer is formed faces the outside of the protection case.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing an overall configuration of a battery pack 100 according to Embodiment 1 of the present invention. The battery pack 100 shown in FIG. 1 includes a case 10, a printed wiring board 40 on which an electric circuit including a control circuit is mounted, conductors, and fixing portions 31 and 32 extending from the case 10 for fixing the printed wiring board 40. The battery pack 100 stores, for example, a lithium ion battery 20. As shown in FIG. 1, the conductor includes a plurality of conductive wires 51 to 55, and is configured to electrically connect the lithium-ion battery 20 and the printed wiring board 40.

FIG. 2 is a diagram schematically showing an example of a circuit configuration formed on the printed wiring board 40. As shown in FIG. Case 10
Inside are a lithium ion battery 20, a printed wiring board 40,
And, they are largely divided into conductors 51 to 55 connecting them. A control circuit is mounted on the printed wiring board 40, and the voltage of the lithium-ion battery 20 is detected by using the control circuit to secure a safe charge / discharge operation of the battery pack. The conductors 51 to 55 are connected to the individual lithium-ion batteries 20 constituting the assembled battery by printed wiring to transmit the voltage and current from the battery (hereinafter, referred to as an assembled battery) forming the lithium-ion battery 20 to the printed wiring board 40. It is configured to connect with the plate 40.

FIG. 3 is a diagram schematically showing a cross-sectional configuration of the battery pack 100 according to the first embodiment. Inside the case 10, a lithium ion battery 20, a printed wiring board 40, and a conductor 50 for connecting the lithium ion battery 20 and the printed wiring board 40 are incorporated. Also,
The fixing portions 31 and 32 for fixing the printed wiring board 40 have a structure extending from the case.

FIG. 4 is a diagram schematically showing a cross-sectional structure of printed wiring board 40 according to the first embodiment. The printed wiring board 40 has electric components mounted on one surface thereof and silk-printed on the other surface (hereinafter, this surface is referred to as a silk-printed surface 60). Furthermore, the printed wiring board 40
A resin 70 having a low intermolecular force, such as a fluororesin, is entirely coated.

FIG. 5 is a diagram schematically showing a cross-sectional structure of the printed wiring board holding structure (center portion) according to the first embodiment. FIG. 5 is a diagram showing the detailed structure of the fixing portions 31 and 32 using the following walls 11 to 14. Walls 11 and 12 are formed as pillar structures for holding the printed wiring board 40 from the upper part of the case 10, and similarly, walls 13 and 12 are formed as pillar structures for holding the printed wiring board 40 from the lower part of the case 10. , 14 are formed. Wall 1
1, 12 and the upper part of the case 10 form a groove, and similarly,
The walls 13, 14 and the lower part of the case 10 also form a groove.

The groove formed between the walls 13 and 14 and the lower part of the case 10 is filled with an adhesive 80, and the printed wiring board 4
0 is inserted and held in the groove filled with the adhesive 80. Similarly, the adhesive 80 is also filled in the groove formed by the walls 11 and 12 and the upper part of the case 10, and the printed wiring board 4
0 is inserted and held in the groove filled with the adhesive 80. Here, an adhesive such as a silyl group-containing special polymer obtained by mixing a silicone resin and an acrylic resin is used. The characteristic of this adhesive is that when the adhesive comes into contact with the electrolytic solution, the acrylic resin contained in the adhesive dissolves in the electrolytic solution and can swell the electrolytic solution.

FIG. 6 is a diagram schematically showing a cross-sectional structure of the printed wiring board holding structure (end portion) according to the first embodiment. The end of the printed wiring board holding structure is the case 10
The walls 17 and 18 provided vertically to the walls 15 and 16 extending from the case 10 and the case 10 surround the electric component mounting surface of the printed wiring board 40 (see FIG. 6A). FIG. 6 (b)
5 is a cross-sectional view of the printed wiring board holding structure as viewed from the silk printed surface 60 of the printed wiring board 40. FIG. The outer peripheral portion of the printed wiring board 40 includes walls 11 and 1 extending from the case 10.
The upper and lower portions are surrounded by 3, the left and right portions are surrounded by walls 17 and 18, and the printed wiring board 40 is entirely surrounded.

Here, as shown in FIG. 5, the printed wiring board 40 is provided with a groove filled with an adhesive 80 (a groove formed by the walls 11, 12 and the upper portion of the case 10, and a groove formed by the walls 13, 1
6 and the lower portion of the case 10), the adhesive 80 fills the entire periphery of the printed wiring board 40 between the walls 11, 13 and the printed wiring board 40 in FIG. Is done. The entire periphery of the printed wiring board 40 and the wall extending from the case 10 are adhered with the adhesive 80, so that the printed wiring board 40 and the wall can serve as one structure.

FIG. 7 is a diagram showing a schematic structure of the printed wiring board holding structure under the case according to the first embodiment when viewed from above. Wall 1 extending from the lower part of case 10
An adhesive 80 is filled in a space surrounded by 6, 13, 14 and a wall 18 extending from the wall 16. The same applies to the upper part of the case, and the description is omitted. Since the printed wiring board 40 is inserted into a space surrounded by these walls and filled with the adhesive 80, the lithium-ion battery 20 (not shown) and the electric component mounting surface of the printed wiring board 40
Partitioned by 0.

The conductors 51 to 55 connecting the lithium-ion battery 20 (not shown) and the printed wiring board 40 extend from the individual batteries. Connection part of conductor 51 and conductor 5
A safety such as avoiding an electrical short circuit can be ensured by separating the gap between the connection portion 2 and the connection portion 2 by 4 mm or more.

FIG. 8 is a view for explaining a reaction when the electrolytic solution comes into contact with the printed wiring board holding structure according to the first embodiment. Electrolyte solution 90 leaking from lithium ion battery 20 (not shown) travels through conductor 50 and contacts printed wiring board 40. However, the printed wiring board 4
The fluororesin 70 coated to zero repels the electrolytic solution 90 due to weak intermolecular force, and prevents the electrolyte solution 90 from contacting the printed wiring board 40. Furthermore, by any chance, the coating of the fluororesin 70 is lost and the electrolyte 90
Contact the printed wiring board 4
The electrolyte 90 acts as a protective film for the printed wiring board 4.
0 is prevented from being adversely affected. Also, the electrolyte 90
Is in contact with the printed wiring board 40 along the surface of the case 10, but the electrolyte 90 enters the electrical component surface of the printed wiring board 40 because the wall 14 and the like extending from the case 10 are sealed with the adhesive 80. Can be prevented.

[0027]

As described above, according to the present invention,
In a battery pack having a built-in chargeable / dischargeable secondary battery or the like, when an electrolyte leaks, damage due to the leak can be prevented.

According to the present invention, even if water is immersed in the battery pack, the surface of the printed wiring board is covered with the resin film having a weak intermolecular force, so that the electric component is protected by the film. Failure of the electric circuit can be prevented.

Further, according to the present invention, since the electric parts are mounted on one side of the printed wiring board and the other side is provided with the electrolytic solution resistance, the printed wiring board itself can be used as a protective wall against the electrolytic solution. Becomes

Further, according to the present invention, since the electric circuit including the control circuit is integrated on one side of the printed wiring board, the structure of the electrolyte protection wall against leakage from the battery can be simplified.

Further, according to the present invention, since the conductor for connecting the battery and the printed wiring board is connected to the surface of the printed wiring board where the electrolyte resistance is improved, the migration is prevented even when the electrolyte leaks. Can be prevented from occurring.

Further, according to the present invention, since the above-described structure is provided in the electric circuit including the control circuit for the battery pack, it is possible to improve the safety of the electric circuit without changing the size of the battery pack. Become.

Further, according to the present invention, by adopting this structure in an electric product incorporating an electric circuit, it is possible to protect electric components from external water, water vapor and the like.

Further, according to the present invention, by adopting the above structure for bonding the printed wiring board and the case to the electric product, the structural strength of the electric product can be increased.

Further, according to the present invention, as the surface treatment of the printed wiring board, a process of forming a protective surface by silk printing and a process of forming a resin film having a weak intermolecular force are performed. Can be improved in safety.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a battery pack according to Embodiment 1 of the present invention.

FIG. 2 is a diagram schematically illustrating an example of a circuit configuration configured on a printed wiring board.

FIG. 3 is a diagram schematically showing a cross-sectional configuration of the battery pack according to the first embodiment.

FIG. 4 is a diagram schematically illustrating a cross-sectional structure of the printed wiring board according to the first embodiment;

FIG. 5 is a diagram schematically illustrating a cross-sectional structure of a printed wiring board holding structure (center portion) according to the first embodiment;

FIG. 6 is a diagram schematically illustrating a cross-sectional structure of a printed wiring board holding structure (end portion) according to the first embodiment;

FIG. 7 is a diagram showing a schematic structure of the printed wiring board holding structure under the case according to the first embodiment when viewed from above;

FIG. 8 is a diagram for explaining a reaction when an electrolytic solution comes into contact with the printed wiring board holding structure according to the first embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Case, 11-18 ... Wall, 20 ... Lithium ion battery, 31-32 ... Fixed part, 40 ... Printed wiring board, 5
0 to 55: conductor, 60: silk-printed surface, 70: fluororesin, 80: adhesive, 90: electrolytic solution, 100: battery pack

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E360 AB54 EA24 ED07 ED22 ED29 EE13 FA12 GA11 GA29 GA30 GA60 GB95 GC08 5H040 AA34 AS14 AS15 AY06 LL06

Claims (7)

[Claims] 1. A protective case for storing a substrate and a battery on which an electric circuit is formed, wherein the substrate is an electric circuit formed on one surface of the substrate, and a back surface of the substrate having the electric circuit. A protective wall substrate having a silk print layer formed on the substrate, and a layer of a low-molecular force resin covering an outer periphery of the substrate on which the electric circuit and the silk print layer are formed. Case. 2. The live part protection case according to claim 1, wherein said low molecular force resin is a fluororesin. 3. The protection wall substrate according to claim 1, wherein the protection wall substrate is disposed and fixed to an inner surface of the protection case such that a surface having the silk print layer faces the stored battery. Live part protection case. 4. The live case protection case according to claim 3, wherein the protection case has a groove into which the periphery of the protection wall substrate is inserted. 5. The protection wall substrate is inserted into a groove inside the protection case and fixed using an adhesive made of a silyl group-containing special polymer to seal the stored battery in the protection case. The live part protection case according to claim 4, characterized in that: 6. The live part protection case according to claim 5, wherein the silyl group-containing special polymer is obtained by mixing a silicone resin and an acrylic resin. 7. A protective case having a substrate on which an electric circuit is formed, wherein the substrate is formed on an electric circuit formed on one surface of the substrate, and on a back surface of the surface of the substrate having the electric circuit. A protective layer substrate having a silk printed layer, and a layer of low molecular force resin covering the outer periphery of the substrate on which the electric circuit and the silk printed layer are formed, wherein the protective wall substrate is one of the protective cases. A live part protection case, comprising a surface, and a surface on which the silk print layer is formed faces the outside of the protection case.