KR101297932B1 - Laptop-computer battery pack having a heat-spreader - Google Patents

Abstract

The present invention relates to a battery pack. The present invention, two or more battery cells electrically connected to charge and discharge; A BMU electrically connected to the battery cell to control charging and discharging of the battery cell; A battery pack for a notebook computer including the battery cell and a pack case for accommodating the BMU, wherein the pack case is characterized in that the inner surface has a heat spreader. The battery pack for a notebook computer according to the present invention prevents the temperature of the battery cells from being excessively increased by dispersing heat accumulated therein without causing an increase in the size of the battery pack, resulting in battery pack malfunction. It is possible to protect the safety of the user from an accident, and to prevent the life of the battery pack is shortened, thereby greatly improving the safety and reliability of the battery pack.

Battery Pack, Refrigerant, Heat Spreader, Heat Sink, Heat Sink

Description

BATTERY-PACK BATTERY PACK HAVING A HEAT-SPREADER

The present invention relates to a battery pack, and more particularly, to a battery pack for a notebook computer provided with a heat spreader to improve the heat generation performance of the battery pack.

A notebook computer has the greatest advantage of being convenient to carry compared to a conventional desktop computer, and one of the biggest roles in enabling such a portable battery is a battery pack which is a power source of the notebook computer.

In general, a battery pack for a notebook computer has a structure in which a plurality of unit cells, such as a cylindrical secondary battery, are electrically connected to each other and mounted in a pack case while a protective circuit element is mounted. As a pack case of a battery pack for a notebook computer, a polycarbonate material having excellent mechanical strength but low thermal conductivity is mainly used.

Therefore, when charging / discharging while the battery pack is mounted on the device, heat generated from the unit cells included in the battery pack is not discharged to the outside through the case, but is accumulated inside the battery pack and deteriorates the unit battery. In addition to this, there is a problem in that it is delivered to the device as it is and degrades the performance of the device.

On the other hand, in the battery pack, as a method for solving the safety problems associated with the temperature rise, a method for blocking the charge-discharge FET device or the fuse is used. In other words, the battery pack for the notebook computer is equipped with a temperature sensing element called a thermistor. When the temperature rises above the set value, the charge / discharge FET element is cut off, and the fuse is blown at an extreme temperature rise. By doing so, the risk of ignition and explosion of the battery cell due to the abnormal temperature rise is prevented. However, if the fuse is blown, it means that the battery pack cannot be used again until the battery pack is repaired, so the user must bear the loss of having to purchase a new battery pack. Moreover, since the safety devices themselves do not provide a means for removing heat accumulated in the battery, the user is still exposed to the risk of fire and explosion of the battery.

Regarding the safety of a battery pack based on a secondary battery, Japanese Patent Application Laid-Open No. 1997-266016 discloses a medium and large battery pack by circulating a cooling liquid between a pack case and a plurality of cylindrical cells housed inside the pack case. A technique for cooling is disclosed. However, this technology has a high cooling efficiency because the liquid refrigerant and the unit cells are in direct contact with each other, which has relatively high cooling reliability, but there is a risk of corrosion and oxidation of the battery due to the direct contact between the liquid refrigerant and the unit cells. There is a problem that the likelihood of occurrence of an internal short circuit or explosion accordingly. In addition, the above technology may be applicable to medium and large battery packs of large devices such as electric vehicles and hybrid vehicles in terms of structure, but there are limitations in applying them to battery packs for notebook computers, which are relatively small.

In addition, Japanese Patent No. 3312852 discloses a technology for a medium-large battery pack in which a refrigerant flow path is formed in a pack case. That is, the patent discloses a technique for forming a predetermined flow path in the pack case and for cooling by flowing a refrigerant through the path. However, the above technique is also applicable to medium and large battery packs of large devices and difficult to apply to battery packs for notebook computers. In order to form the coolant flow path in the pack case, the thickness of the pack case must be at least a predetermined size, which causes a problem that the size of the pack case increases. In addition, due to the characteristics of the battery pack for the notebook computer, a lot of external force is applied during use, the formation of the refrigerant flow path can reduce the mechanical strength of the pack case may cause a safety problem rather.

Therefore, the development of a cooling technology that can be effectively applied to the battery pack for notebook computers is urgently required.

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

In particular, in the related art, a heat sink is mainly used for heat dissipation of an electronic device such as a battery cell, but a battery pack has a problem in that there is no space for providing a heat sink therein.

The inventors of the present application pay close attention to the above problems and repeat the in-depth studies and experiments, and when a heat spreader is installed on one side of the pack case to manufacture a battery pack for a notebook computer, a unit constituting the battery pack By utilizing the structural characteristics of the cylindrical battery cell as a battery to maximize the battery pack without removing the size of the battery pack, and to effectively remove the heat generated during the charge and discharge of the battery cell, the safety of the battery can be significantly improved, The present invention has been completed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art,

Two or more battery cells electrically connected and charged / discharged;

A BMU electrically connected to the battery cell to control charging and discharging of the battery cell;

A pack case accommodating the battery cell and the BMU therein

In the battery pack for a notebook computer comprising a,

The pack case provides a battery pack for a notebook computer, characterized in that provided with a heat spreader on its inner surface.

In addition, in the present invention, the heat spreader provides a battery pack for a notebook computer, characterized in that the thickness is within the range of 2 ~ 6 mm.

In the present invention, the heat spreader is provided with a hollow portion, the refrigerant flows in the hollow portion, provides a battery pack for a notebook computer, characterized in that the refrigerant is spontaneously circulated through the hollow portion.

In the present invention, the refrigerant is a battery pack for a notebook computer, characterized in that the one selected from water, freon gas, ammonia gas, acetone, methanol, ethanol.

In another aspect, the present invention provides a battery pack for a notebook computer, characterized in that the heat spreader is connected to the heat spreader, the heat dissipation member exposed to the outside of the pack case is further provided.

In addition, in the present invention, the heat dissipation member provides a battery pack for a notebook computer, characterized in that the heat radiation fin or a heat sink.

The battery pack for a notebook computer according to the present invention prevents the temperature of the battery cells from being excessively increased by dispersing heat accumulated therein without causing an increase in the size of the battery pack, resulting in battery pack malfunction. It is possible to protect the safety of the user from an accident, and to prevent the life of the battery pack is shortened, thereby greatly improving the safety and reliability of the battery pack.

Hereinafter, the present invention will be described in detail.

According to the present invention,

Two or more battery cells electrically connected and charged / discharged;

A BMU electrically connected to the battery cell to control charging and discharging of the battery cell;

A pack case accommodating the battery cell and the BMU therein

In the battery pack for a notebook computer comprising a,

The pack case is characterized in that the inner surface with a heat spreader.

The battery pack according to the present invention is a battery pack for a notebook computer having a structure in which two or more battery cells form an electrical connection and a battery row (row) arranged in series or in parallel in a pack case, the battery cell The heat spreader is provided on the inner surface of the pack case, and is configured to remove heat generated during charging and discharging of the battery cell.

The heat spreader is preferably a thin film heat spreader having a thickness within a range of 2 to 6 mm. It may not be sufficient to remove heat of the battery cells in the range of less than 2 mm, there is a fear that the space for accommodating the battery cells is insufficient in the range exceeding 6 mm.

The heat spreader may be a polymer or plastic material with good conductivity or a metal material with good conductivity. In addition, the heat spreader may include a hollow portion, a refrigerant flowing in the hollow portion, and a refrigerant spontaneously circulating through the hollow portion. The hollow part refers to an empty space in the heat spreader and may be formed of the same material as the heat spreader.

In particular, the hollow part may be formed in a heat pipe shape in the heat spreader as shown in FIG. 2, or may be provided with an empty space in the entire heat spreader as shown in FIG. 3.

The hollow portion should be formed thinner than the thickness of the heat spreader, specifically, it is preferably formed within the range of 0.5 ~ 4 mm. If it is less than 0.5 mm, there is a fear that the refrigerant in the hollow portion does not convectively circulate and the heat transfer performance may deteriorate. In the range exceeding 4 mm, the outer plate of the heat spreader becomes too thin and the heat spreader itself may be structurally weak in strength. There is.

In the present invention, the refrigerant is not forcedly circulated by a pump or the like, but circulated by heat generated by the battery cell. The principle of heat transfer occurs through conduction of the heat spreader itself, but mainly through heat transfer through refrigerant convection.

The refrigerant may be used without limitation, conventional refrigerant used in the manufacture of a cooling device. Examples of such refrigerants include freon gas, ammonia, acetone, methanol, ethanol, and the like, and water may be used.

In some cases, a heat dissipation member adjacent to and connected to the heat spreader may be further installed to cool the refrigerant having a temperature rise while being circulated along the heat spreader. Such a heat dissipation member is preferably configured to have at least a portion thereof exposed to the outer surface of the pack case to emit heat to the outside of the pack case. In addition, the heat dissipation member may have a structure in which a heat dissipation fin or a heat dissipation plate is formed at a portion exposed to the outer surface of the pack case to increase the cross-sectional area in contact with the outside air to improve cooling efficiency.

The BMU is a control element used in a notebook computer battery pack, which will be apparent to those skilled in the art. The BMU performs functions such as a PCM (protective circuit module) of a small battery pack and a battery management system (BMS) of a large battery pack.

The position at which the BMU is mounted is not particularly limited, but as an example, the BMU may be installed at a position adjacent to the inner surface of the pack case, and may have a structure in which an external connection terminal of the BMU is exposed to the outside through the pack case. have.

The pack case constituting the battery pack of the present invention may be formed in various forms. For example, the pack case may be formed of an upper case and a lower case, and after the heat spreader and the BMU are installed on the lower case, the pack case may be covered by the upper case. It may be a sealing structure.

Since a structure related to the battery pack for other notebook computers and a method of manufacturing the same are well known in the art, further description thereof will be omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, this is for the easier understanding of the present invention, not intended to limit the scope of the invention to the embodiments.

Example

1 is a perspective view showing an interior of a battery pack provided with a heat spreader according to an embodiment of the present invention.

Referring to FIG. 1, in one embodiment, the battery pack 100 has six cylindrical battery cells 300 making electrical connections, and two battery strings in which three battery cells 300 are connected in series are pack cases. It consists of the structure accommodated in 110. In addition, the inner surface of the pack case 110 is provided with a heat spreader 200 through which the refrigerant is circulated, and the heat dissipation fin 220 for dissipating heat of the circulated refrigerant is exposed to the outside from the inside of the pack case. The heat dissipation fin 220 is installed so that a portion thereof is exposed to the outer surface of the pack case 110, thereby dissipating heat to the outside of the pack case 110. In addition, a BMU 250 that controls charging and discharging of the battery cell 300 is provided on one inner surface of the pack case 110.

4 illustrates a schematic diagram of a refrigerant circulation type battery pack having battery cells, a heat spreader, a BMU, a heat dissipation member, and the like installed on the lower case and covering the upper case.

Referring to FIG. 4, although the inside of the battery pack 100 is sealed by the combination of the upper case 114 and the lower case 112, the refrigerant circulated through the heat spreader 200 is formed in the battery pack 100. By circulating the inside, the heat generated during operation of the battery pack 100 is absorbed and released to the outside through the heat dissipation fin 220, so that a specific battery cell is excessively heated, or heat generated from the battery cells 100 ) To prevent accumulation inside.

Although described above with reference to the drawings according to an embodiment of the present invention, those of ordinary skill in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

1 is a perspective view of the inside of a refrigerant circulation battery pack according to an embodiment of the present invention.

2 is a structural diagram of a heat spreader having a heat pipe-shaped refrigerant flow path that may be used in the present invention, and FIG. 3 is a structural diagram of a heat spreader provided with a hollow part in an entire metal plate.

4 is a schematic diagram of a refrigerant circulation type battery pack complete with a battery cell, a heat spreader, a BMU, a heat dissipation member, and the like installed on a lower case and covering the upper case;

Brief description of the reference numbers

100: battery pack 110: pack case

112: lower case 114: upper case

200: heat spreader 220: heat radiation fins

250: BMU 300: battery cell

Claims (6)

Two or more battery cells electrically connected and charged / discharged; A BMU electrically connected to the battery cell to control charging and discharging of the battery cell; A pack case accommodating the battery cell and the BMU therein In the battery pack for a notebook computer comprising a, The pack case has a heat spreader on its inner surface, The heat spreader is provided with a hollow portion, the battery pack for a notebook computer, characterized in that the refrigerant flows in the hollow portion. The battery pack of claim 1, wherein the heat spreader has a thickness within a range of 2 to 6 mm. delete The battery pack of claim 1, wherein the refrigerant is one selected from water, freon gas, ammonia gas, acetone, methanol, and ethanol. The battery pack of claim 1, further comprising a heat dissipation member connected to the heat spreader and exposed to the outside of the pack case. The battery pack of claim 5, wherein the heat dissipation member is a heat dissipation fin or a heat dissipation plate.

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