JP2002093470A - Battery pack - Google Patents

Abstract

(57) [Problem] To provide a battery pack in which the temperature of a plurality of batteries housed in a pack case is equalized and the heat dissipation of the batteries is improved. SOLUTION: An opening 3 is formed at a position corresponding to a storage position of a battery 1 in a pack case 2, a heat conductive silicon 6 is filled in the opening 3, and an aluminum thin plate 5 is adhered to an outer surface of the pack case 2. Is done. Since the plurality of batteries 1 are each thermally connected to the aluminum thin plate 5 through the heat conductive silicon 6, the battery temperature of each battery 1 can be equalized, and the battery temperature can be lowered by radiating heat from the aluminum thin plate 5. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack used as a battery power source for portable information devices and the like.

[0002]

2. Description of the Related Art In general, a battery pack is constructed by housing a plurality of secondary batteries and a circuit board or the like which constitutes a protection circuit for protecting the secondary batteries from overcharge or overdischarge in a pack case. Is done. Secondary batteries are easily affected by battery temperature.Especially if there is an imbalance in the battery temperature of multiple secondary batteries, charging / discharging efficiency changes for each secondary battery, and multiple secondary batteries with different battery capacities are combined. Thus, the state becomes the same as when the battery pack is configured. The imbalance of the battery temperatures generated in the plurality of secondary batteries is caused by a difference between a heat source and a heat radiation inside the pack case and a heat source outside the pack case.

Japanese Patent Application Laid-Open No. H11-233164 discloses a means for eliminating an imbalance in the battery temperature of each secondary battery in a battery pack containing a plurality of secondary batteries in a pack case.
Is known. This configuration,
As shown in FIG. 6, a plurality of secondary batteries 22a to 22g and a circuit board 23 are accommodated in a pack case 21, and a heat conductive sheet 25 is arranged so as to connect the plurality of secondary batteries 22a to 22g. I have. In the invention of the prior application, the heat source in the pack case 21 is on the circuit board 23, the battery temperature of the secondary battery 22a closest to the circuit board 23 increases, and a temperature difference occurs between the secondary batteries 22b to 22g. The problem is that the heat of the secondary battery 22a is transferred to the other secondary batteries 22b to 22g by the heat conductive sheet 25, thereby dispersing the heat and eliminating the imbalance in the battery temperature.

[0004]

However, even if the unbalance of the battery temperature is eliminated by the heat conductive sheet, the heat amount is accumulated in the pack case. There has been a problem that the temperature rises and the secondary battery is thermally deteriorated, and the cycle life of the secondary battery is shortened.

[0005] Further, since the contact area of the heat conductive sheet with each secondary battery is small, heat conduction between the secondary battery and the heat conductive sheet is not sufficient, and the effect of correcting the battery temperature imbalance is obtained. Had a low problem.

[0006] Further, as the size and thickness of the battery pack have been reduced in response to the demand for smaller and thinner portable devices, an extra space is actually formed in the pack case as shown in FIG. As shown in FIG. 7, a plurality of secondary batteries 22 are fitted to the space of the pack case 27 to reduce the thickness. At this time, if the heat conductive sheet 28 is disposed on the secondary battery 22, the thinning of the battery pack will be hindered. Thermal conductive sheet 28
Has a thickness of about 0.5 mm, but it is necessary to suppress this slight thickness in a device required to be thin.

[0007] An object of the present invention is to provide a battery pack provided with a configuration that eliminates an unbalance in the battery temperature of a plurality of secondary batteries without hindering the thickness reduction.

[0008]

According to a first aspect of the present invention, there is provided a battery pack having a width smaller than the diameter of a battery at a location where each battery is accommodated in a pack case accommodating a plurality of batteries. Is formed, and a heat conductive sheet having good heat conductivity is fixed to the outer surface of the pack case so as to close the plurality of openings, and heat conduction having good heat conductivity is provided in the plurality of openings so as to be in contact with the battery and the heat conductive sheet. Each battery is thermally connected to a heat conductive sheet by a heat conductive material, so that the heat of each battery is conducted through the heat conductive sheet and a plurality of secondary The battery temperature of the battery is equalized. In addition, since the heat conductive sheet is disposed outside the pack case, heat is dissipated to suppress a rise in the temperature inside the pack case, thereby suppressing thermal deterioration of the battery and improving cycle life.

In the battery pack according to the second aspect of the present invention, an opening having a width smaller than the diameter of the battery is formed in a cylindrical direction of the battery at a storage position of each battery in a pack case for storing a plurality of cylindrical batteries. The battery is housed in the pack case so that a part of the arc surface enters the opening, and a heat conductive sheet having good heat conductivity is fixed to the outer surface of the pack case to close the plurality of openings, A plurality of openings are filled with a heat conductive material having good heat conductivity so as to be in contact with the battery and the heat conductive sheet. Since a part of the battery pack is accommodated in the pack case, it is effective in reducing the thickness of the battery pack. In addition, since a heat conductive material is filled in the opening for realizing this, and the battery is thermally connected to the heat conductive sheet, a battery pack is realized which realizes thinning and eliminates imbalance in battery temperature.

In the battery pack according to a third aspect of the present invention, an opening having a width smaller than the diameter of the battery is formed in a cylindrical direction of the battery at a storage position of each battery in a pack case for storing a plurality of cylindrical batteries. The battery is housed in the pack case such that a part of the arc surface thereof is exposed to the outside of the pack case from the opening, and is thermally conductive so as to contact the battery exposed from the plurality of openings on the outer surface of the pack case. It is characterized in that a good heat conductive sheet is fixed, and a part of the battery that has entered the opening is exposed to the outside, and the heat conductive sheet is arranged so as to be in contact with the exposed part Thus, a battery pack is realized in which the battery temperature is unbalanced while the thickness is reduced.

In each of the above structures, when the battery pack is mounted on a device using the same,
When it is configured to be in contact with a plate surface having good thermal conductivity provided in the device, heat radiation is further promoted, which is effective in lowering the battery temperature.

[0012] Further, when an uneven shape for increasing the surface area is formed on the outer surface of the heat conductive sheet, the heat radiating area is increased, the heat radiation is promoted, and it is effective to lower the battery temperature.

Further, the heat conductive sheet may be configured as a display panel for displaying a product of the battery pack.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention.

Each of the first and second embodiments described below shows a battery pack configured by housing eight batteries configured as lithium ion secondary batteries in a pack case. (First Embodiment) FIG. 1 is a plan view of a case lid 2a constituting a pack case 2 at positions corresponding to eight batteries 1 housed in a case body 2b (see FIG. 2). Is formed with an opening 3 whose width is smaller than the diameter of the cylindrical battery 1 and whose longitudinal direction is the column direction. Further, as shown in FIG. 3, both sides of the opening 3 in the width direction are formed on the round surface 4 corresponding to the arc of the battery 1, so that the case body 2b containing the battery 1 is held by the case lid 2a. When the battery pack is closed, a part of the cylindrical surface of the battery 1 enters the round surface 4 and the opening 3 as shown in FIG.
The housing height of the battery 1 in the diameter direction is reduced, and the battery pack can be made thinner.

As shown in FIG. 2, the battery 1 is disposed in the case body 2b, closed by the case lid 2a, and the battery 1 is accommodated in the pack case 2, and then, as shown in FIG. Is filled with heat conductive silicon (heat conductive material) 6, and the opening 3
A thin aluminum plate (heat conductive sheet) 5 is stuck so as to close. With this configuration, each battery 1 is thermally connected to the aluminum thin plate 5 by the heat conductive silicon 6 at the opening area of the opening 3, and the eight batteries 1 are thermally connected by the aluminum thin plate 5, and the eight batteries 1 are connected to each other. The battery temperature of the battery 1 is equalized. Since the thermal connection between the battery 1 and the aluminum thin plate 5 is made in the area of the opening 3, heat conduction is efficiently performed.

Also, since the heat of each battery 1 is transferred from the heat conductive silicon 6 to the aluminum thin plate 5 on the outer surface of the pack case 2, the heat is radiated outside without being accumulated in the pack case 2, An increase in the battery temperature of the battery 1 is suppressed, thermal deterioration is prevented, and cycle life can be improved.

When it is desired to further improve the heat radiation from the aluminum thin plate 5, the surface area can be increased by forming an uneven shape on the outer surface. In addition, when a metal portion that comes into surface contact with the aluminum thin plate 5 is provided in a battery pack housing portion of a device using the battery pack, a heat radiation effect can be improved.

Although the opening 3 is formed only in the case lid 2a in the configuration of the present embodiment, the opening 3 is also formed in the case main body 2b, and if the same configuration is adopted, each battery 1 has a diameter. Since the heat is radiated on both sides in the direction, the heat radiation effect and the equalization of the battery temperature can be further improved.

In this embodiment, an example in which a cylindrical battery is used as the battery 1 has been described. However, even in the case of a flat rectangular battery, an opening is formed at a position corresponding to the battery in the pack case. The battery can be thermally connected to the aluminum thin plate adhered to the pack case by the heat conductive silicon filled in the opening. (Second Embodiment) FIG. 4 shows a main part configuration of a battery pack according to a second embodiment. The overall configuration is the same as that of the first embodiment, and the common elements are the same. The reference numerals are attached and the description is omitted.

In FIG. 4, the width of the opening 13 formed in the case lid 12a is increased to increase the amount of the cylindrical surface of the battery 1 that enters the opening 13, and the top of the cylindrical surface forms the case lid 12a. The battery 1 is housed in the pack case 12 at the same position as the outer surface of the battery 1. In this state, when the aluminum sheet 15 is adhered to the outer surface of the case lid 12a as shown in FIG.
5, the plurality of batteries 1 are
5, and the battery temperature is equalized. Further, since the heat of the battery 1 is radiated through the aluminum thin plate 15, an increase in the battery temperature is suppressed, and the cycle life can be improved without thermal deterioration of the battery 1.

In the above configuration, since the contact between the battery 1 and the aluminum thin plate 15 is a line contact, when there is difficulty in heat conduction, the width of the opening 18 is made larger as shown in FIG. The top of the cylindrical surface of the battery 1 is formed so as to protrude from the outer surface of the case lid 16a.
The contact area between the battery 7 and the battery 1 can be increased. Since the aluminum thin plate 17 has an arc surface 17a corresponding to the cylindrical surface on the opening portion 18, the arc surface 17a
The inner surface a contacts the battery 1 to increase the contact area.

In the configuration of the present embodiment, since the battery 1 is directly connected to the aluminum thin plates 15 and 17, the inner surfaces of the aluminum thin plates 15 and 17 are coated with an electrically insulating material having good thermal conductivity to electrically connect them. It is desirable to be insulated.

In each of the embodiments described above,
The product display of the battery pack can be printed on the aluminum thin plates 5, 15, and 17, and can be configured to also serve as a name plate for the product display.

[0025]

As described above, according to the present invention, the plurality of rechargeable batteries housed in the pack case are connected to the heat conduction fixed to the outer surface of the pack case through the openings formed in the pack case. Since the battery is thermally connected, heat conduction between the batteries is performed, and the battery temperature is equalized. In addition, since the heat of the battery is transferred to the heat conductive sheet and radiated from the heat conductive sheet, thermal deterioration of the battery is prevented,
The cycle life is improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a battery pack according to an embodiment.

FIG. 2 is a sectional view showing the configuration of the battery pack according to the first embodiment.

FIG. 3 is an enlarged cross-sectional view illustrating a configuration of a main part of the battery pack according to the first embodiment.

FIG. 4 is an enlarged cross-sectional view illustrating a main part configuration of a battery pack according to a second embodiment.

FIG. 5 is an enlarged cross-sectional view showing a configuration of a main part showing a modification of the battery pack according to the second embodiment.

FIG. 6 is a cross-sectional view showing a configuration of a battery pack according to the related art.

FIG. 7 is a cross-sectional view showing a configuration of a battery pack according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Pack case 2a Case lid 3, 13, 18 Opening 5, 15, 17 Aluminum thin plate (heat conductive sheet) 6 Thermal conductive silicon (thermal conductive material)

Claims (6)

[Claims] An opening having a width smaller than the diameter of the battery is formed at a storage position of each battery in a pack case for storing a plurality of batteries, and a heat conductive material is formed on an outer surface of the pack case so as to close the plurality of openings. A battery pack characterized in that a good heat conductive sheet is fixed, and a plurality of openings are filled with a heat conductive material having good heat conductivity so as to be in contact with the battery and the heat conductive sheet. 2. An opening having a width smaller than the diameter of the battery is formed in a cylindrical direction of the battery at a storage position of each battery in a pack case for storing a plurality of cylindrical batteries. A heat conductive sheet having good heat conductivity is accommodated in the pack case so as to enter into the opening, and a heat conductive sheet having good heat conductivity is fixed to an outer surface of the pack case so as to close the plurality of openings. A battery pack filled with a heat conductive material having good heat conductivity so as to be in contact with the battery pack. 3. An opening having a width smaller than the diameter of the battery is formed in the battery case of the pack case for accommodating a plurality of cylindrical batteries in the cylindrical direction of the battery. A heat conductive sheet, which is housed in the pack case so as to be exposed to the outside of the pack case from the opening and is in contact with the battery exposed from the plurality of openings, is fixed to the outer surface of the pack case. A battery pack characterized in that: 4. The heat conductive sheet is configured such that when the battery pack is mounted on a device using the battery pack, the heat conductive sheet is in contact with a plate having good heat conductivity provided on the device. The battery pack according to claim 1. 5. The battery pack according to claim 1, wherein an uneven shape for increasing a surface area is formed on an outer surface of the heat conductive sheet. 6. The battery pack according to claim 1, wherein the heat conductive sheet is configured as a display panel for displaying a product of the battery pack.