KR20150089481A - PCM with Novel Structure and Secondary Battery Including the Same - Google Patents

Abstract

The present invention relates to a protection circuit module which protects a secondary battery from charge overcurrent and charge overcurrent, over discharge, and overcharge. The protection circuit module includes a first FET device which is off when overcharge or charge overcurrent is detected, a second FET device which is separated from the first FET device by a space separation part, is installed to the upper side of a PCB, and is off when over discharge or discharge overcurrent is detected, a third terminal fuse which is separated from the space separation part to the PCB or touches it upwards, detects the temperature change of the space separation part, and is broken at a setting temperature or more, at least one via hole which is vertically formed on the PCB to connect the upper and lower sides of the PCB to the space separation part, and a line which is formed on the lower side of the PCB.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a protection circuit module having a novel structure and a secondary battery including the same,

The present invention relates to a protection circuit module having a novel structure and a secondary battery including the same.

Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy or clean energy is increasing. As a part of this, the most active field of research is electric power generation and storage.

At present, a typical example of an electrochemical device utilizing such electrochemical energy is a secondary battery, and the use area thereof is gradually increasing.

2. Description of the Related Art [0002] Recently, as technology development and demand for portable devices such as portable computers, portable phones, and cameras have increased, the demand for secondary batteries as energy sources has increased sharply. Among such secondary batteries, they exhibit high energy density and operating potential, Many researches have been made on a lithium secondary battery having a long self discharge rate, and it has been commercialized and widely used.

However, despite the above advantages, the lithium secondary battery has a fundamental problem that safety is low. For example, when the battery is overcharged, the decomposition reaction of the electrolytic solution at the electrode is promoted to generate a flammable gas, and the overcurrent caused by various causes such as an internal short-circuit increases the temperature of the battery, cause. Such generation of gas due to overcharging, overcurrent, or the like causes the battery to ignite, and in some cases, the battery may explode. In addition, even if it is not an overcurrent, the temperature rise due to other causes causes the above problems. Therefore, various safety elements for solving such problems are incorporated in the lithium secondary battery.

A typical example of such a safety device is a PTC (Positive Temperature Coefficient), a fuse, and a bimetal. In this case, the PTC is a safety device that cuts off the current due to an increase in resistance due to an overcurrent, Is a safety device that cuts off the current when the temperature rises due to heat. The bimetal is a safety element that cuts off the electrical connection due to the difference in thermal expansion coefficient when the temperature rises.

All of these safety devices have the effect of solving the problem caused by the overcurrent as described above, but they can not solve the problems caused by the overvoltage such as overcharge, overdischarge, and the like. The overdischarge of the battery does not cause a safety problem, but it causes collapse of the negative electrode material and causes a significant deterioration of the performance of the battery. Therefore, in order to solve the overvoltage of the battery, a protection circuit module (PCM) is generally mounted on the secondary battery.

However, such a protection circuit module includes a FET (Field Effect Transistor) element for charge control, a FET element for discharge control, and a wiring, and heat generated therefrom can cause a problem in the safety of the secondary battery. Therefore, some technologies use a three-terminal fuse that senses the temperature in the protection circuit module and blocks the current at a set temperature in order to solve the above problem and ensure the high temperature stability of the secondary battery.

However, even in the case of using such a three-terminal fuse, it is difficult to detect an abnormal heat generation that occurs simultaneously in the charge control FET device, the discharge control FET device, and the wiring, and the accurate temperature measurement inside the protection circuit module There is a problem that it is difficult.

Therefore, there is a high need for the development of a protection circuit module capable of solving the above problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have found that a semiconductor device having at least one or more apertures vertically perforated on a printed circuit board so that the upper and lower surfaces of the printed circuit board are communicated at the space- When a secondary battery protection circuit module including a via hole is used, the three-terminal fuse is quickly destroyed by accurately detecting the abnormal heating state and the abnormal temperature state of the protection circuit module, thereby improving the safety of the secondary battery And the present invention has been accomplished.

Therefore, the protection circuit module for protecting the secondary battery from overcharging, over discharging, charging overcurrent and discharging overcurrent according to the present invention is mounted on the upper surface of the printed circuit board, and is turned off when an overcharge or overcharge current is detected, A second FET element which is mounted on the upper surface of the printed circuit board so as to be spaced apart from the first FET element and which is turned off when over discharge or discharge overcurrent is detected, A three-terminal fuse disposed so as to contact or separate upward from the substrate and configured to detect a temperature change of the space-spaced portion and to be broken at a set temperature or higher, a printed circuit board One or more via holes vertically perforated on the substrate, and at least one via hole formed in the lower surface of the printed circuit board It characterized in that it comprises.

In one specific example, when the three-terminal fuse is disposed spaced apart upwardly from the printed circuit board at the spaced apart portion, the separation distance of the three-terminal fuse end is, in one specific example, in the range of 0.01 mm to 0.2 mm . This is because it is difficult to accurately detect the temperature of the space portion in the three-terminal fuse when the distance exceeds 0.2 mm.

In one specific example, the via hole transfers heat generated in the wiring formed on the lower surface of the printed circuit board to the space separating portion, and more specifically, conveys heat by convection and / or radiation.

The inventors of the present application have found that the portion where heat is generated most in the protection circuit module is the first FET device, the second FET device, and the wiring. In order to accurately detect the abnormal heating state and temperature of the protection circuit module, It is most preferable to measure the temperature of the space portion where heat is concentrated in the first FET device, the second FET device, and the wiring.

In order to facilitate the heat transfer between the first FET device and the second FET device to the space separating part, a configuration in which a thermal glue is applied to the space separating part may be considered. In this case, It is difficult to effectively transmit the heat generated by the wiring formed in the wiring, and the additional step of applying the summer glue is required. The space occupied by the summer glue increases in size due to the increase in the size of the entire protection circuit module.

On the other hand, in the protection circuit module according to the present invention, a via hole is formed in the printed circuit board at the space portion formed by the first FET device and the second FET device, so that the temperature of the space- It is possible to effectively sense the abnormal temperature state as a whole and to smoothly transfer the heat generated in the wiring through the via hole to the spaced apart portion so that not only the abnormal heating state of the FET but also the abnormal heating state of the wiring can be detected effectively, The three-terminal fuse can be quickly destroyed when the state is detected, so that the stability of the secondary battery can be improved.

In one specific example, the diameter of the via hole according to the present invention may be from 0.05 mm to 0.2 mm, and more specifically from 0.1 mm to 0.2 mm. When the diameter of the via hole is less than 0.05 mm, it is difficult to transfer the heat generated in the wiring formed on the lower surface of the printed circuit board to the space spacing. When the via hole is larger than 0.2 mm, it is difficult to form the wiring on the lower surface of the printed circuit board. It is not preferable since a failure may occur in the circuit construction.

The viahole may be perforated in a range of 1 to 10, and when the via hole is punched in more than 10 holes, it is difficult to print the wiring on the lower surface of the printed circuit board, Therefore, it is not preferable.

On the other hand, when the secondary battery is exposed to a high temperature, a large amount of gas is generated due to the decomposition of the electrolytic solution and the internal pressure rises, which may cause explosion and fire of the secondary battery. It is necessary to limit the temperature rise of the protection circuit module by designing the three-terminal fuse to be destroyed at a certain temperature or higher. Thus, in one specific example, the set temperature at which the three-terminal fuse is configured to break may range from 100 degrees Celsius to 150 degrees Celsius, and more specifically from 130 degrees Celsius to 140 degrees Celsius.

The three-terminal fuse may include two terminals to be energized at the time of charging or discharging, and one terminal to be energized at a set temperature or higher to induce destruction of the fuse.

The present invention also provides a secondary battery including the above-described protection circuit module, and the secondary battery is not particularly limited as long as it is a charge / discharge battery requiring safety, and can be preferably used for a lithium secondary battery.

The lithium secondary battery may be classified into a lithium ion battery, a lithium ion polymer battery, and a lithium polymer battery according to the type of a battery component. Any battery may be used as long as it is charged / discharged by reversible insertion / Do.

The present invention provides a device including the secondary battery as a power source, and the device includes, but is not limited to, a mobile phone, a portable computer, a smart phone, a smart pad, a tablet PC, and a netbook .

As described above, in the protection circuit module according to the present invention, the via holes are formed so that the upper surface and the lower surface of the printed circuit board are communicated with each other at the space portion formed by the first FET device and the second FET device, The three-terminal fuse is located on the formed space portion. By measuring the temperature of the space portion where the heat is concentrated in the protection circuit module, it is possible to effectively detect the abnormal temperature condition as a whole, It is possible to effectively detect the abnormal heat generation state of the wiring as well as the abnormal heat generation state of the FET. Accordingly, the three-terminal fuse can be quickly destroyed when the abnormal state is detected, thereby improving the stability of the secondary battery .

1 is a plan view schematically illustrating a secondary battery protection circuit module according to an embodiment of the present invention;
2 is a front view schematically illustrating a secondary battery protection circuit module according to an embodiment of the present invention;
FIG. 3 is an enlarged view showing in detail the portion A in FIG. 2; FIG.
4 is a front view schematically illustrating a protection circuit module according to another embodiment of the present invention.

Hereinafter, the present invention will be described with reference to Examples. However, the following Examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

FIGS. 1 and 2 schematically show a plan view and a front view, respectively, of a secondary battery protection circuit module 100 according to an embodiment of the present invention.

Referring to these drawings, a first FET device 300 is mounted on a top surface of a printed circuit board 200, and a first FET device 300 and a second spacing portion 210 are disposed, 301 are mounted on the upper surface of the printed circuit board 200 and the three-terminal fuses 400 are disposed upward from the printed circuit board 200 at the spaced apart portions.

The first terminal 410, the second terminal 411 and the third terminal 412 are electrically connected to the three-terminal fuse 400. The first terminal 410 and the second terminal 411 are electrically connected to each other. The third terminal 412 is energized at a temperature higher than the set temperature to induce the three-terminal fuse 400 to be destroyed.

Four via holes 220 are vertically formed in the spacing part 210 so as to communicate with the upper and lower surfaces of the printed circuit board 200. Although not shown in the drawing, A wiring is formed.

3 shows an enlarged view of the portion A of FIG. 2 in more detail in order to explain the via hole 220 of the printed circuit board 200 and the space separating portion 210 where heat is concentrated .

3, the diameter D of the via hole 220 facilitates the transfer of heat generated in the wiring formed on the lower surface of the printed circuit board to the space separating portion 210, 0.0 > mm < / RTI >

The distance L between the spacing part 210 and the three-terminal fuse 400 is preferably 0.01 mm to 0.2 mm, which is a range capable of accurately sensing the temperature due to heat concentrated in the spacing part 210.

4 schematically shows a protection circuit module 100 in which a three-terminal fuse 400 is in contact with a printed circuit board 200. Referring to FIG. 4 in comparison with FIG. 2, Terminal fuse 400 has a similar configuration except that the terminal 400 contacts the spacing portion 210 of the printed circuit board 200. In this case, It has the advantage of being able to measure accurately.

The spacing part 210 of the protective circuit module 100 according to the present invention is formed in a space formed on the lower surface of the printed circuit board 200 and the heat generated in the first FET device 300 and the second FET device 301 Heat generated in the wiring is concentrated, and most of the heat generated in the wiring is transmitted through the via hole 220 by convection and radiation. Therefore, it is possible to effectively detect the entire abnormal temperature state by measuring the temperature of the space portion 210 where the heat is concentrated in the protection circuit module 100, and the heat generated in the wiring through the via hole 220 can be detected in the space The three-terminal fuse 400 can be quickly destroyed when the abnormal state is detected, so that the three-terminal fuse 400 can be quickly destroyed when the abnormal state is detected, Thereby improving the stability of the battery.

≪ Example 1 >

A first FET device is mounted on a top surface of a printed circuit board, a second FET device is mounted on a top surface of the printed circuit board with a space between the first FET device and the top surface of the printed circuit board, And a three-terminal fuse was arranged.

In addition, five via holes having a diameter of 0.05 mm are vertically perforated on the printed circuit board so that the top and bottom surfaces of the printed circuit board are communicated with each other at the space spaced apart, and wiring is formed on the bottom surface of the printed circuit board, .

≪ Example 2 >

A protection circuit module was fabricated in the same manner as in Example 1, except that the three-terminal fuse was separated from the printed circuit board by 0.1 mm upward in the first embodiment.

≪ Example 3 >

A protection circuit module was manufactured in the same manner as in Example 1, except that the three-terminal fuse was separated from the printed circuit board by 0.2 mm upward from the space separating portion.

<Example 4>

A protection circuit module was fabricated in the same manner as in Example 1, except that the three-terminal fuse in Example 1 was separated 0.3 mm upward from the printed circuit board at the spacing portion.

&Lt; Example 5 >

A protection circuit module was fabricated in the same manner as in Example 1, except that the three-terminal fuse was separated from the printed circuit board by 0.4 mm upward in the first embodiment.

&Lt; Example 6 >

A protection circuit module was fabricated in the same manner as in Example 1, except that the 3-terminal fuse was separated from the printed circuit board by 0.5 mm upward in the space separator.

&Lt; Example 7 >

A protection circuit module was fabricated in the same manner as in Example 1, except that the three-terminal fuse was separated from the printed circuit board by 0.6 mm upward from the space portion.

&Lt; Example 8 >

A protection circuit module was manufactured in the same manner as in Example 1, except that the three-terminal fuse was separated from the printed circuit board by 0.8 mm upward from the space separating portion in Example 1.

<Experimental Example 1>

When the set temperature of the three-terminal fuse of the first to eighth embodiments is set to 138 DEG C and two charging or discharging terminals electrically connected to the three-terminal fuse are energized, the first FET element, the second FET element, And the actual temperature of the instantaneous space separating portion where the three-terminal fuse disrupted by recognizing the temperature of the space-spaced portion as the set temperature was measured. In addition, the error with respect to the actual temperature of the space-spaced part when the three-terminal fuse breaks was calculated based on the set temperature. The results are shown in Table 1 below.

Printed circuit board
Distance between three-terminal fuses
(mm) When 3-terminal fuse is destroyed
Actual temperature of space
(° C) error
(%) Example 1 0 138.0 0.0 Example 2 0.1 141.2 2.3 Example 3 0.2 144.8 4.9 Example 4 0.3 148.9 7.9 Example 5 0.4 154.5 12.0 Example 6 0.5 162.6 17.8 Example 7 0.6 173.1 25.4 Example 8 0.8 193.1 39.9

Referring to Table 1, the protection circuit module according to each of Embodiments 1 to 3 is destroyed in an error range of 5% of the set temperature, while the protection circuit modules according to Examples 4 to 8 have an error range of 5% Is exceeded. These results indicate that the protection circuit module of the first to third embodiments can further improve the safety of the secondary battery as compared with the protection circuit module of the fourth to eighth embodiments.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (13)

A protection circuit module for protecting a secondary battery from overcharging, overdischarging, charging overcurrent, and discharging overcurrent,
A first FET element mounted on an upper surface of the printed circuit board and turned off when overcharging or charging overcurrent is detected;
A second FET element which is mounted on an upper surface of the printed circuit board with a space between the first FET element and the ground, and is turned off when over discharge or discharge overcurrent is detected;
A three-terminal fuse arranged in contact with or separated from the printed circuit board at the space spaced apart from the printed circuit board, the three-terminal fuse configured to detect a temperature change of the space-spaced portion and break at a set temperature or higher;
At least one via hole vertically perforated in the printed circuit board so that the upper surface and the lower surface of the printed circuit board are communicated with each other at the space portion; And
A wiring formed on a lower surface of the printed circuit board;
The secondary battery protection circuit module comprising: The secondary battery protection circuit module according to claim 1, wherein a distance of the upwardly separated end of the three-terminal fuse in the space separating portion is in a range of 0.01 mm to 0.2 mm. The secondary battery protection circuit module according to claim 1, wherein the via hole transfers heat generated in the wiring formed on a lower surface of the printed circuit board to the space separator. The secondary battery protection circuit module according to claim 3, wherein the via hole transfers heat generated in the wiring formed on the lower surface of the printed circuit board to the space separating part by convection and / or radiation. The secondary battery protection circuit module according to claim 1, wherein the via hole has a diameter of 0.05 mm to 0.2 mm. The secondary battery protection circuit module according to claim 1, wherein one to ten via holes are formed in the printed circuit board. The secondary battery protection circuit module according to claim 1, wherein the set temperature is set in a range of 100 degrees Celsius to 150 degrees Celsius. The secondary battery protection circuit module according to claim 1, wherein the set temperature is set in a range of 130 to 140 degrees Celsius. The secondary battery protection circuit module according to claim 1, wherein the three-terminal fuse includes two terminals to be energized at the time of charging or discharging, and one terminal to energize at a predetermined temperature or higher to induce destruction of the fuse. A secondary battery comprising a protection circuit module according to any one of claims 1 to 9. The secondary battery according to claim 10, wherein the secondary battery is a lithium secondary battery. A device according to claim 10, comprising a secondary battery as a power source. 13. The device of claim 12, wherein the device is selected from a cell phone, a portable computer, a smart phone, a smart pad, a tablet PC, and a netbook.

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