JP2014086342A - Battery pack and manufacturing method therefor - Google Patents

Abstract

Disclosed is a battery pack capable of high-efficiency production and a method of manufacturing the same, while improving the safety and extending the life of the battery by dissipating heat generated in the unit cell.
A battery pack includes a core pack, an outer case, and a heat transfer resin portion. The case member 12 of the outer case 10 has a bowl shape, and the unit cells 21 to 25 of the core pack 20 have a cylindrical axis arranged along the inner surface of the bottom wall of the case member 12. The heat transfer resin portion 30 is filled and formed over a range from the bottom wall inner surface of the case member 12 to the side wall opening edge, and a part of both cylinder ends in each of the unit cells 21 to 25 and a part of the cylinder outer peripheral surface. It is in close contact with. The remaining portions of the unit cells 21 to 25 are not in contact with the heat transfer resin portion 30, and at least a part thereof faces the space 10 a of the outer case 10. Some of the lead plates 27 and 28 connected to the unit cells 21 to 25 are also in contact with the heat transfer resin portion 30.
[Selection] Figure 3

Description

  The present invention relates to a battery pack and a manufacturing method thereof, and more particularly to a heat dissipation structure for a unit cell.

The battery pack is widely used as a power source for electric tools, electric assist bicycles, electric motorcycles, hybrid electric vehicles, electric vehicles and the like, and also for power storage in homes and stores.
The internal unit cell generates heat when the battery pack is mounted on a device for use or when charging. Dissipating this heat to the outside is important from the viewpoint of the charge / discharge characteristics and life characteristics of the battery pack. An example of a configuration for dissipating heat generated in an internal unit cell to the outside is disclosed in Patent Documents 1, 2, 3, and the like.

As shown in FIG. 8, the battery pack disclosed in Patent Document 1 includes a case member 911 and 912 and a core pack 920 housed therein as main elements. Both the case members 911 and 912 have a bottomed cylindrical shape and have internal spaces 911a and 912a.
The core pack 920 includes a plurality of unit cells 921 to 928, lead plates 929 and 930 that connect them, a battery holder 931, and a substrate 932.

In the battery pack shown in FIG. 8, heat generated in the unit cells 921 to 928 is transmitted to the case members 911 and 912 through the battery holder 931 and is radiated to the outside from the outer surfaces of the case members 911 and 912.
As shown in FIG. 9, the battery pack disclosed in Patent Document 3 includes case members 941 and 942, unit cells 951 housed therein, connection terminals 961 and 962 connected to the unit cells 951, and case members. A resin part 930 filled in an internal space 942a constituted by 941 and a case member 942 is configured as a main element.

  In the battery pack shown in FIG. 9, heat generated in the unit cell 951 is transmitted to the case members 941 and 942 through the resin portion 930 and is radiated to the outside from the outer surfaces of the case members 941 and 942.

JP 2006-196277 A JP 2011-86475 A JP 2004-39485 A

  However, it is difficult to provide a battery pack with high productivity while ensuring the heat dissipation of the unit cell with the prior art including the inventions disclosed in Patent Documents 1 to 3. Specifically, in the battery pack disclosed in Patent Document 1, heat is transferred through the contact surface between the outer peripheral surface of the unit cell and the battery holder, but from the viewpoint of productivity and the like, A small gap may be formed between the outer peripheral surface and the battery holder, but this is insufficient from the viewpoint of ensuring heat dissipation.

  Further, in the battery pack disclosed in Patent Document 3, since the resin portion 930 is formed in the entire internal space 942a, the weight increases, and complicated operations are required during production. That is, when the resin material is filled in the internal space 942a, it is necessary to leave no gap between the case member 942 and the unit cell 951 or the like. Therefore, when forming the resin portion 930, the filling speed of the resin material cannot be increased too much, and it takes a long time to fill the entire internal space 942a with the resin portion 930. In particular, when the bottom surface of the unit cell is not flat but curved, it is necessary to fill the resin material over time.

In this way, in a configuration that requires complicated work during production, the manufacturing cost increases.
The present invention has been made in order to solve the above-described problems, and is capable of producing high-efficiency while improving the safety and extending the life by radiating the heat generated in the unit cell. It is an object of the present invention to provide a battery pack that can be used and a manufacturing method thereof.

Therefore, the present invention adopts the following configuration.
The battery pack according to the present invention includes a unit cell and an exterior case.
-The unit cell is cylindrical.
The exterior case is composed of a plurality of case members, and a unit cell storage space is formed inside by combining them.

Among the plurality of case members constituting the outer case, one case member having a bowl shape is included, and the unit cell is arranged along the inner surface of the bottom wall of the one case member. Has been.
In the battery pack according to the present invention, the internal space of the one case member is filled with a heat transfer member that transmits the heat of the unit cell to the one case member over a range from the inner surface of the bottom wall to the side wall opening edge. Is formed. In the unit cell, each part of both cylinder ends and a part of the outer peripheral surface of the cylinder are in close contact with the heat transfer member, and at least a part of the remaining part is in contact with the heat transfer member. Absent.

The battery pack manufacturing method according to the present invention (hereinafter referred to as “the first manufacturing method according to the present invention”) includes the following steps.
A step of preparing a bowl-shaped case member, and a step of filling the internal space of the one case member with a heat transfer member having fluidity over a range from an inner surface of the bottom wall to a side wall opening edge. A step of storing the cylindrical unit cell in the inner space of the one case member filled with the heat transfer member having fluidity so that the cylinder axis is along the inner surface of the bottom wall of the one case member. The step of sealing the opening of the one case member with another case member In the method of manufacturing a battery pack according to the present invention, the filling amount of the heat transfer member having fluidity to the internal space of the one case member is: When the unit cell is stored, the heat transfer member having the fluidity is an amount that does not leak beyond the side wall opening edge of the one case member. Each part of the cylinder end and part of the cylinder outer peripheral surface But heat transfer member closely in contact, at least a portion of the remaining portion, is not in contact with the heat transfer member.

In addition, the battery pack manufacturing method according to the present invention (hereinafter, referred to as “second manufacturing method according to the present invention”) includes the following steps.
-A step of preparing a bowl-shaped case member-A cylindrical unit cell is stored in the internal space of the one case member so that the cylinder axis is along the inner surface of the bottom wall of the one case member. The step of filling the internal space of the one case member in which the unit cell is stored with a heat transfer member having fluidity over a range from the inner surface of the bottom wall to the side wall opening edge. The process of sealing the opening of the member with another case member In the method of manufacturing the battery pack according to the present invention, after executing the sealing process, the unit cell has a part of each cylinder end and one part of the cylinder outer peripheral surface. Are in close contact with the heat transfer member, and at least a portion of the remaining portion is not in contact with the heat transfer member.

In the battery pack according to the present invention, each part of both cylinder ends of the unit cell and a part of the outer peripheral surface of the cylinder are in close contact with the heat transfer member, so that the heat generated in the unit cell passes through the heat transfer member. Is transmitted to a single case member and effectively radiated to the outside. Therefore, it is excellent from the viewpoint of ensuring safety and life characteristics.
Further, in the battery pack according to the present invention, the heat transfer member is not filled and formed in the entire internal space of the outer case, but at least a part of the remaining portion of the unit cell excluding the above portion is not in contact with the heat transfer member. ing. For this reason, compared with the case where the heat transfer member is filled and formed in the entire outer case, the weight can be reduced, and the time required for the filling operation can be shortened.

  Further, in the battery pack according to the present invention, each part of both cylinder ends of the unit cell and a part of the outer peripheral surface of the cylinder are in close contact with the heat transfer member. In the heat transfer to the heat distribution, the heat distribution can be made uniform to some extent, which is excellent from the viewpoint of life characteristics. That is, in the cylindrical unit cell, the current collector from the electrode body is usually arranged on one cylinder end side, but in the present invention, each part of both cylinder ends is a heat transfer unit. Since it is in close contact with the member, it is difficult to cause temperature variation between the ends of both cylinders.

  Further, in the battery pack according to the present invention, at least a part of the remaining portion of the unit cell is not in contact with the heat transfer member, and the filling time can be shortened when filling the material during production. In this case, an air layer hardly remains between the inner surface of the bottom wall of the case member and the unit cell. Therefore, in the battery pack according to the present invention, the manufacturing cost can be reduced due to high work efficiency, and heat dissipation can be ensured.

As described above, the battery pack according to the present invention can be produced with high efficiency while improving the safety and extending the life by radiating the heat generated in the unit cell.
In the battery pack according to the present invention, for example, the following variation configurations can be adopted.
In the battery pack which concerns on this invention, the structure that the heat transfer member is filled and formed only in the internal space of one case member in the said structure is employable. As a result, high-efficiency production is possible, weight can be reduced, and heat generated in the unit cell can be released to the outside with high efficiency as described above.

  In the battery pack according to the present invention, in the above configuration, a pole terminal is provided at one cylindrical end of the unit cell, a lead plate is connected to the pole terminal, and at least a part of the lead plate is a heat transfer member. The structure of being covered with can be employed. When such a configuration is adopted, the heat generated in the unit cell is transmitted from the heat transfer member to the one case member via the lead plate. Therefore, higher heat dissipation can be ensured by increasing the heat transfer path.

  In the battery pack according to the present invention, in the above configuration, the unit cell is housed in the outer case while being held by the battery holder, and the battery holder is provided with a window portion. It is possible to employ a configuration in which each part of both cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member through the window portion. When such a configuration is adopted, impact resistance can be ensured by holding the unit cell in the outer case with the battery holder. Since a part of the outer surface of the unit cell and the heat transfer member are in close contact with each other through the window provided in the battery holder, a heat transfer path from the unit cell to the one case member can be secured. Therefore, high safety and long life can be achieved.

  In the battery pack according to the present invention, in the above-described configuration, it is possible to adopt a configuration in which at least a part of the outer surface of the bottom wall of the case member is exposed to the outside when the case is mounted on the device. Thereby, the heat transmitted from the unit cell to the one case member via the heat transfer member is radiated from the outer surface of the bottom wall of the one case member exposed to the outside. Therefore, heat is not generated and is radiated to the outside.

  In addition, when a heat transfer member is filled and formed in the internal space of one case member where the outer surface of the bottom wall is exposed to the outside when the device is mounted, the heat transfer member becomes an impact force absorbing material when an impact force is applied from the outside. Will also work. Therefore, in the battery pack according to the present invention, when the above configuration is adopted, it is possible to suppress the influence of an external impact force on the outer case and the unit cell housed therein.

  In the battery pack according to the present invention, in the above-described configuration, a safety valve is provided at one end of the unit cell, and at least a part of the safety valve is not covered with the heat transfer member. it can. By adopting such a configuration, the operation of the safety valve is not hindered by the heat transfer member with respect to a configuration in which the entire outer surface of the unit cell is covered with the heat transfer member, and high safety is ensured. Can do.

  The battery pack which concerns on this invention can employ | adopt the structure that a heat transfer member consists of a resin material which has electrical insulation in the said structure. By adopting such a configuration, it is not necessary to separately cover the periphery of the unit cell, the lead plate, etc. with an insulator, so that the number of parts can be reduced, and the work efficiency during production is increased. can do. Therefore, the manufacturing cost can be reduced.

  In the 1st manufacturing method which concerns on this invention, a unit cell is accommodated after filling the heat transfer member with respect to the internal space of one case member. Therefore, the heat transfer member can be filled from the opening in one case member, and since the unit cell is not accommodated in this state, a void or the like hardly remains even if the filling rate of the heat transfer member is not lowered. That is, in the prior art shown in FIG. 9, it is necessary to store the unit cell first, and when the heat transfer member (resin material) is filled there, it is placed between the inner surface of the case bottom wall and the unit cell. It is necessary to keep the filling rate of the heat transfer member low so that no voids remain.

  On the other hand, in the first manufacturing method according to the present invention, since the heat transfer member is filled before the unit cell is housed, the problem that the air gap remains hardly occurs even if the filling rate of the heat transfer member is not reduced. In the first manufacturing method according to the present invention, only a part of the outer surface of the unit cell is in close contact with the heat transfer member, and at least a part of the remaining part is not in contact with the heat transfer member. Thus, the amount of the heat transfer member is adjusted. For this reason, the weight can be reduced as compared with the case where the entire interior of the exterior case is filled with the heat transfer member, the amount of the heat transfer member can be reduced, and the working time can be reduced. Reduction can be achieved.

Further, in the first manufacturing method according to the present invention, the unit cell can be fixed to one case member, and the subsequent assembly process can be executed, so that the workability is improved.
The filling amount of the heat transfer member is set so as not to exceed the side wall opening edge of one case member even when the unit cell is accommodated.
In the second manufacturing method according to the present invention, the heat transfer member is filled after the unit cell is accommodated in the internal space of the one case member. The amount of the heat transfer member filled is a part of the outer surface of the unit cell. Is in close contact with the heat transfer member, but at least part of the remaining portion is not in contact with the heat transfer member. In other words, since the heat transfer member is filled in one case member up to the position closer to the bottom surface than the side wall opening edge of the one case member, the weight after completion can be reduced by reducing the amount of heat transfer member filling. Can be reduced.

Moreover, since the filling amount of the heat transfer member is suppressed, it is possible to reduce the time and work for filling, and to reduce the manufacturing cost.
Furthermore, in the second manufacturing method according to the present invention, as in the first manufacturing method, the unit cell can be fixed to one case member and the subsequent assembly process can be executed, so that the workability is improved. .

In the first manufacturing method and the second manufacturing method according to the present invention (hereinafter collectively referred to as “the manufacturing method according to the present invention”), the following variation methods can be employed.
In the manufacturing method according to the present invention, in the above method, a method in which the heat transfer member is filled and formed only in the internal space of the one case member after the sealing step is performed. Thereby, highly efficient production is possible, the battery pack can reduce the weight of the battery pack, and can efficiently release the heat generated in the unit cell to the outside as described above. It can be.

  In the manufacturing method according to the present invention, in the above method, a pole terminal is provided at one cylindrical end of the unit cell, and a lead plate is connected to the pole terminal, to the internal space of one case member. After the storage of the unit cell and the filling of the heat transfer member, a method in which at least a part of the lead plate is covered with the heat transfer member can be employed. Thereby, the heat generated in the unit cell can be transferred to the one case member via the lead plate and the heat transfer member, and a battery pack with higher heat dissipation can be manufactured.

  In the manufacturing method according to the present invention, in the above method, the unit cell is stored in the internal space of the one case member in a state of being held by the battery holder, the battery holder is provided with a window portion, It is also possible to adopt a method in which a part of both cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member through the window portion in the battery holder. In the case of adopting such a method, a battery pack in which the unit cell in the outer case is held by the battery holder, thereby ensuring impact resistance can be manufactured. And, since a part of the outer surface of the unit cell and the heat transfer member are in close contact with each other through the window provided in the battery holder, a heat transfer path from the unit cell to the one case member is also ensured and high. A battery pack with improved safety and longer life can be manufactured.

It is a schematic perspective view which shows the external appearance structure of the battery pack 1 which concerns on embodiment of this invention. 2 is a schematic exploded perspective view showing an internal configuration of the battery pack 1. FIG. 2 is a schematic cross-sectional view showing an internal configuration of battery pack 1. FIG. 3 is a schematic cross-sectional view showing a part of the internal configuration of the battery pack 1. FIG. (A) is a schematic diagram which shows the positional relationship of the unit cell 21 and the heat transfer resin part 30 in the battery pack which concerns on embodiment, (b) is the unit cell 821 in the battery pack which concerns on a comparative example. , 822 and the heat transfer resin portion 830 is a schematic diagram showing the positional relationship. It is a schematic process diagram for explaining a method for manufacturing the battery pack 1, wherein (a) shows a filling process of a resin material, and (b) shows a housing process of the core pack 20. It is a schematic process diagram for demonstrating the manufacturing method of the battery pack 1 which concerns on a modification, Comprising: (a) shows the accommodation process of the core pack 20, (b) shows the filling process of the resin material. It is an expansion | deployment perspective view which shows the structure of the battery pack which concerns on a prior art. It is sectional drawing which shows the structure of the battery pack which concerns on a prior art.

Below, the form for implementing this invention is demonstrated using drawing. In addition, the specific example shown below is an example used for easily explaining the configuration of the present invention and the operations and effects produced from the configuration, and the present invention is not limited to the components essential to the invention. The following specific examples are not limited at all.
[Embodiment]
1. Configuration of Battery Pack 1 The configuration of the battery pack 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the battery pack 1 according to the present embodiment has an exterior formed of an exterior case 10 having a flat rectangular exterior shape. The exterior case 10 is configured by joining two case members 11 and 12. Both the case members 11 and 12 have a bottomed shallow dish shape, and the opening edges are joined to each other with the opening edges abutting each other.
Here, in the battery pack 1 according to the present embodiment, at the time of mounting on the device, the case member 11 side is inserted into the mounting portion of the device, and the bottom wall outer surface of the case member 12 (the outer surface on the lower side in the Z-axis direction) ) Is exposed to the outside from the device mounting portion.

  As shown in FIG. 2, the core pack 20 is accommodated in the internal spaces 11 a and 12 a configured by the case members 11 and 12. The core pack 20 includes five unit cells 21 to 25, a battery holder 26, and lead plates 27 and 28 for connecting the unit cells 21 to 25 as main elements. Each of the unit cells 21 to 25 has a cylindrical appearance, and has positive and negative terminals on both end faces, and a safety valve on one end face (detailed illustration is omitted). The types of the unit cells 21 to 25 are, for example, lithium ion batteries.

The unit cells 21 to 25 are arranged in a state in which the cylinder axis is along the inner surface of the bottom wall of the case member 12. Specifically, they are arranged along the X-axis direction.
The battery holder 26 has a cylindrical holding space corresponding to each of the five unit cells 21 to 25, and a window is provided in each Z-axis direction lower portion of the portion in which each unit cell 21 to 25 is accommodated. A portion 26a is provided. A part of each outer peripheral surface 21a of the unit cells 21 to 25 is exposed to the outside from the window portion 26a. Further, both end faces of the unit cells 21 to 25 are exposed to the outside for joining the lead plates 27 and 28.

  As shown in FIG. 2, a heat transfer resin portion 30 is filled in the internal space 12 a of one case member 12 constituting the exterior case 10. The heat transfer resin portion 30 is made of, for example, a silicone resin material, an epoxy resin material, or a urethane resin material. Further, the heat transfer resin portion 30 is filled with a capacity so as not to exceed the opening edges 12b to 12e of the four side walls when the core pack 20 is stored in the internal space 12a of the case member 12. .

2. Unit cells 21 to 25 and heat transfer resin portion 30
The relationship between the unit cells 21 to 25 and the heat transfer resin portion 30 in the battery pack 1 will be described with reference to FIGS. 3 and 4.
As shown in FIG. 3, in the internal space 10 a of the outer case 10 in the battery pack 1, the heat transfer resin portion extends from the bottom wall inner surface of the case member 12 to the side wall opening edge in a state where the core pack 20 is accommodated. 30 is filled and formed. In other words, the entire outer periphery of each of the unit cells 21 to 25 in the core pack 20 is not covered with the heat transfer resin portion 30, but a part of both end surfaces and a part of the outer peripheral surface are the heat transfer resin portion 30. The remaining portion is not in contact with the heat transfer resin portion 30. The part which is not in contact with the heat transfer resin part 30 includes a part where the safety valve in each of the unit cells 21 to 25 is provided. As a result, even when the safety valve is activated when the unit cell is abnormal, the heat transfer resin portion 30 does not impede this, and high safety can be ensured.

Note that at least a portion of the portion that is not in contact with the heat transfer member 30 has a gap with the inner surface of the case member 11.
In the battery pack 1, some of the lead plates 27 and 28 that connect the unit cells 21 to 25 are in close contact with the heat transfer resin portion 30.
As shown in FIG. 4, the unit cells 21 to 25 (only the unit cells 21 and 22 are shown in FIG. 4) held by the battery holder 26 pass through the windows 26 a provided in the battery holder 26. A portion of the surface 21a,... Is exposed and comes into close contact with the heat transfer resin portion 30 (see the arrow A portion). Thereby, increase of the contact area of each outer peripheral surface 21a, ... of the unit cells 21-25 and the heat transfer resin part 30 is aimed at.

3. Heat Dissipation Form in Battery Pack 1 The heat release form in the battery pack 1 will be described with reference to FIG. 5A schematically illustrates the configuration of the battery pack 1 according to the present embodiment, and FIG. 5B schematically illustrates a configuration in which the postures of the unit cells 821 and 822 are changed as a comparative example. Shown in
As shown in FIG. 5A, in the battery pack 1 according to the present embodiment, the unit cells 21 to 25 (in FIG. 5A, the unit cell) with the cylindrical axis along the inner surface of the bottom wall of the case member 12. 21 is shown), and the heat transfer resin portion 30 is provided on each part of both end faces 21b, 21c,... And each part of the outer peripheral surfaces 21a,. It comes to come in close contact with it.

  Here, in the unit cells 21 to 25 having a cylindrical external shape, the positive and negative electrode plates of the electrode body at one end (for example, the end on the side where the sealing plate is joined) are provided inside the outer can. Current is collected. Therefore, in the unit cells 21 to 25 adopting such a form, the portion indicated by the arrow B1 generates more heat at the time of charge / discharge or the like than the portion indicated by the arrow B2.

In the present embodiment, the part pointed by the arrow B1 and the part pointed by the arrow B2 are each in close contact with the heat transfer resin part 30, so that it is difficult to cause uneven temperature in the unit cells 21 to 25. It is desirable from the viewpoint of extending the life and safety.
The lead plates 27 and 29 joined to the electrode terminal 21d and the end surface 21c on the end surface 21b of the unit cell 21 are also in close contact with the heat transfer resin portion 30, so that the lead plates 27 and 29 are interposed via the lead plates 27 and 29. Heat is also radiated along the path, and this also makes it difficult for temperature non-uniformity to occur. Here, in the battery pack 1 according to the present embodiment, at least some of the lead plates 27 to 29,... Connected to the electrode terminals of the unit cells 21 to 25 are in the heat transfer resin portion 30. Close contact.

  As shown in FIG. 3 and the like, in the battery pack 1 according to the present embodiment, the heat transfer resin in the internal space of the case member 12 where at least a part of the outer surface of the bottom wall is externally exposed when the device is mounted. The portion 30 is filled and formed. By adopting such a configuration, the heat generated in the unit cells 21 to 25 is radiated to the outside through the heat transfer resin portion 30 from the case member 12 where at least a part of the outer surface of the bottom wall is exposed to the outside. . Therefore, a high heat dissipation effect can be obtained.

Further, by forming the heat transfer resin portion 30 on the case member 12 on the side exposed to the outside when the device is mounted, the heat generated in the unit cells 21 to 25 is selectively guided to the case member 12 and the device side Heat transfer to a certain case member 11 is suppressed. Thereby, when the battery pack 1 which concerns on this Embodiment is used, the thermal influence on a mounting apparatus can also be suppressed.
On the other hand, in the comparative example shown in FIG. 5B, the unit cells 821 and 822 have a cylindrical axis along the direction (Z-axis direction) perpendicular to the inner surface of the bottom wall of the case member (not shown). Are arranged. And the unit cell 821 and the unit cell 822 have the longitudinal direction opposite to the Z-axis direction. Specifically, in the unit cell 821, the end surface 821b to which the sealing plate is joined is on the upper side in the Z-axis direction, and the end surface 821c that is the bottom surface of the outer can is on the lower side in the Z-axis direction. On the other hand, in the unit cell 822, the end surface 822b to which the sealing plate is joined is on the lower side in the Z-axis direction, and the end surface 822c that is the bottom surface of the outer can is on the upper side in the Z-axis direction.

  In the comparative example, the heat transfer resin portion 830 is in close contact with a part of the end surface 821c and the outer peripheral surface 821a of the unit cell 821, and a part of the end surface 822b and the outer peripheral surface 822a of the unit cell 822. On the other hand, the end surface 821b of the unit cell 821, the end surface 822c of the unit cell 822, and the outer peripheral surfaces 821a and 822a of the unit cells 821 and 822 are not in contact with the heat transfer resin portion 830. .

  In the comparative example, the lead plate 829 connected to the end surface 821c of the unit cell 821 and the lead plate 831 connected to the electrode terminal 822d of the end surface 822b of the unit cell 822 are in contact with the heat transfer resin portion 830. The lead plate 827 connected to the electrode terminal 821d on the end surface 821b of the unit cell 821 and the end surface 822c of the unit cell 822 is not in contact with the heat transfer resin portion 830.

Therefore, in the comparative example, a temperature distribution is generated between the arrow C1 portion and the arrow C2 portion of the unit cell 821 and between the arrow D1 portion and the arrow D2 portion of the unit cell 822, which is a safety factor. There is a problem from the viewpoint of improving the service life.
As described above, the battery pack 1 according to the present embodiment is excellent in the heat dissipation characteristics of the heat generated in the unit cells 21 to 25, and is excellent from the viewpoint of ensuring safety and extending the life.

  Further, in the present embodiment, the heat transfer resin portion 30 is filled and formed in the internal space of the case member 12 where at least a part of the outer surface of the bottom wall is exposed to the outside from the device mounting portion when the device is mounted. When receiving an impact force, the heat transfer resin portion 30 becomes a buffer portion for the impact force, and the influence of the impact force on the unit cells 21 to 25 can be suppressed. It will continue to be safe.

4). Manufacturing Method A manufacturing method of the battery pack 1 according to the present embodiment will be described with reference to FIG. In the following description, only a part of the manufacturing process of the battery pack 1 will be described. A well-known technique can be applied to a portion that omits the description.
First, as shown in FIG. 6A, a bottomed shallow dish-like case member 12 is prepared and arranged so that the opening faces upward in the Z-axis direction. And the resin material for heat transfer resin parts which has fluidity | liquidity is filled with respect to the internal space 12a of the case member 12 (arrow E). At this time, the filling amount of the resin material is set so that the resin material does not exceed the side wall opening edges 12b to 12e of the case member 12 even when the core pack 20 is accommodated (does not overflow).

Next, as shown in FIG. 6B, the core pack 20 is stored in the internal space 12a of the case member 12 filled with the resin material for the heat transfer resin portion 30 having fluidity. At this time, as described above, the resin material does not leak out.
Here, when the core pack 20 shown in FIG. 6B is housed, the resin material for the heat transfer resin portion 30 is in a state of being fluid before being cured.

Thereafter, although not shown, the case member 11 closes the opening of the case member 12 to complete the manufacture of the battery pack 1.
As described above, in the method of manufacturing the battery pack 1 according to the present embodiment, when the heat transfer resin portion 30 is filled, the resin material can be filled from the wide opening of the case member 12, thereby ensuring high working efficiency. can do. Further, since the core pack 20 is not accommodated when the resin material is filled, there is no problem that a gap (air pocket) remains between the inner surface of the bottom wall of the case member 12 and the bottom surface portion of the core pack 20.

[Modification]
The modification regarding the manufacturing method of the battery pack 1 is demonstrated using FIG. In the following description, only a part of the manufacturing process of the battery pack 1 will be described. A well-known technique can be applied to a portion that omits the description.
First, as shown in FIG. 7A, in the manufacturing method according to this modification, the core pack 20 is accommodated in the prepared internal space 12 a of the case member 12. In this modification, at this time, the internal space 12a is not filled with the resin material for the heat transfer resin portion 30.

  Next, as illustrated in FIG. 7B, the heat transfer resin is formed from the gap between the inner surface of the side wall of the case member 12 and the core pack 20 with respect to the internal space 12 a of the case member 12 in which the core pack 20 is accommodated. The resin material for the portion 30 is filled (arrow F). Also at this time, the filling amount of the resin material is set such that the resin material does not exceed the side wall opening edges 12b to 12e of the case member 12 (does not overflow).

Thereafter, although not shown in the same manner as described above, the case member 11 closes the opening of the case member 12 to complete the manufacture of the battery pack 1.
[Other matters]
In the above embodiment and modification, the unit cells 21 to 25 are accommodated in the outer case 10 while being held by the battery holder 26, but the battery holder 26 is not necessarily an essential component. The unit cells connected by the lead plate can be stored in the outer case as they are without being held by the battery holder.

Moreover, in the said embodiment and modification, although the window part 26a was provided in the battery holder 26 and this decided to increase the contact area of the unit cells 21-25 and the heat transfer resin part 30, FIG. It may not be the window part 26a of a form as shown. For example, a porous battery holder having a large number of holes may be employed.
Moreover, in the said embodiment and modification, although it decided to employ | adopt the unit cells 21-25 which have a cylindrical external shape, if the external shape of a unit cell is a cylinder shape, it will receive a limitation to this. Absent. For example, a prismatic unit cell can be adopted.

Moreover, in the said embodiment and modification, although the structure provided with the five unit cells 21-25 was employ | adopted, about the sum of a unit cell, it is not limited to this. For example, it can also be set as the structure which comprises 1-4 unit cells, and the structure which comprises 6 or more unit cells can also be employ | adopted.
Moreover, in the said embodiment and modification, although the type of the unit cells 21-25 was made into the lithium ion battery, the battery type is not limited to this. For example, an alkaline battery such as a nickel cadmium battery or a nickel metal hydride battery can be employed.

  Moreover, in the said embodiment and modification, although the five unit cells 21-25 were hold | maintained with the battery holder 26 about the core pack 20 accommodated in the exterior case 10, in addition to this, a circuit board is also used. It can also be set as the structure comprised. In this case, considering the waterproofness of the circuit board, it is desirable from the viewpoint of improving safety that the circuit board is embedded in the heat transfer resin portion 30.

Moreover, in the said embodiment and modification, it was supposed that the exterior case 10 was comprised with the combination of the two case members 11 and 12, but the exterior case was combined with the combination of three or more case members. It may be configured.
Moreover, in the said embodiment and modification, although it was decided that the lead plates 27-29 partly contacted the heat transfer resin part 30 together with a part of the outer surface of the unit cell, It is not always necessary to contact the heat transfer resin portion. However, from the viewpoint of ensuring heat dissipation, it is desirable that at least a part of the lead plate is in close contact with the heat transfer resin portion, and the entire portion of the lead plate excluding the connection portion with the unit cell is the heat transfer resin portion. It is desirable to keep close contact.

  In the above embodiment and modification, the heat transfer resin portion 30 is filled and formed over a certain range in the height direction from the inner surface of the bottom wall of the case member 12. It is also possible to fill and form the heat transfer resin portion 30 over a certain range in the height direction from the wall inner surface. However, when the battery pack is attached to the device, it is desirable to fill and form the heat transfer resin portion in the internal space of the case member where the outer surface of the bottom wall and the like are exposed to the outside in order to ensure heat dissipation.

  Moreover, as shown in FIG. 3 etc., in the said embodiment and modification, suppose that a part of both end surfaces of the unit cells 21-25 do not contact the heat transfer resin part 30, and this heat transfer resin part 30 The part where the safety valve of each unit cell 21-25 was provided in the part which does not contact was also included. Therefore, when the location where the safety valve is provided is different from the above-described embodiment depending on the configuration of the unit cell, etc., the arrangement of the unit cell and the formation mode of the heat transfer resin portion are appropriately determined in consideration of the location. Can be set.

  Moreover, in the said embodiment and modification, although the heat transfer resin part 30 which consists of resin materials was employ | adopted as a heat transfer member, the heat transfer member does not necessarily need to be comprised only from the resin material. For example, the heat transfer member may be composed of a composite material of a high thermal conductivity fiber (Cu, Nb, Ta, Mo, W, etc.) and a resin material, or instead of the high thermal conductivity fiber, Cu-W, Alloys such as Cu—Mo, ceramics such as AlN, ceramics metals such as Al—SC and Si—SiC, and the like can also be used.

  Furthermore, as a material constituting the heat transfer member, a resin material mixed with an electrically insulating filler can be used. In this case, as the electrically insulating filler, metal oxide (for example, aluminum oxide, zinc oxide), metal hydroxide (for example, aluminum hydroxide), metal nitride (for example, aluminum nitride, boron nitride), Metal oxynitride (for example, aluminum oxynitride) or the like can be used.

When the heat transfer member is conductive, the surface of the unit cell or the lead plate may be electrically insulated.
In the embodiment and the modification described above, the heat transfer resin portion 30 is filled and formed only in the internal space of one case member (case member 12), and the other case member (case member 11) side has no element. Although the configuration in which the batteries 21 to 25 are not in contact with each other is adopted, the present invention only needs to have a configuration in which at least a part of the unit cells 21 to 25 is not in contact with the heat transfer resin portion 30 on the case member 11 side. . For example, the heat transfer member 30 and the unit cells 21 to 25 may be housed in the internal space of the case member 12, and after the case member 11 is assembled, the assembly may be slowly shaken in that state. In this case, not all of the side of the case member 11 in the unit cells 21 to 25 are in contact with the heat transfer resin portion 30, but a part is in contact and the rest is not in contact. Even in such a configuration, the same effect as described above can be obtained.

  In the above-described embodiment and modification, the assembly is not particularly shaken, so that only the internal space of the case member 12 is filled with the heat transfer resin 30.

  The present invention is useful for realizing a battery pack with high productivity while ensuring heat dissipation of the unit cell.

1. Battery pack 10. Exterior case 11,12. Case member 20. Core pack 21-25. Unit cell 26. Battery holder 27-29. Lead plate 30. Heat transfer resin part

Claims (12)

A cylindrical unit cell,
An outer case that is configured by a plurality of case members and that constitutes a storage space for the unit cell therein by combining them;
With
The plurality of case members constituting the exterior case include one case member having a bowl shape,
The unit cell has a cylindrical axis disposed along the inner surface of the bottom wall of the one case member,
The inner space of the one case member is filled with a heat transfer member that transmits heat of the unit cell to the one case member over a range from the inner surface of the bottom wall to the side wall opening edge,
In the unit cell, each part of both cylinder ends and a part of the outer peripheral surface of the cylinder are in close contact with the heat transfer member, and at least a part of the remaining part is in contact with the heat transfer member. Battery pack characterized by not. The battery pack according to claim 1, wherein the heat transfer member is filled only in an internal space of the one case member. One cylindrical end of the unit cell is provided with a pole terminal, and a lead plate is connected to the pole terminal,
The battery pack according to claim 1 or 2, wherein at least a part of the lead plate is covered with the heat transfer member. The unit cell is stored in the outer case in a state of being held by a battery holder,
The battery holder is provided with a window,
The unit cell is characterized in that each part of the cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member through a window portion in the battery holder. The battery pack according to claim 3. The battery pack according to any one of claims 1 to 4, wherein at least a part of an outer surface of the bottom wall of the one case member is exposed to the outside when the case member is mounted. The unit cell is provided with a safety valve at one end of the cylinder,
The battery pack according to any one of claims 1 to 5, wherein at least a part of the safety valve is not covered with the heat transfer member. The battery pack according to any one of claims 1 to 6, wherein the heat transfer member is made of a resin material having electrical insulation. A step of preparing a bowl-shaped case member;
Filling the internal space of the one case member with a heat transfer member having fluidity over a range from the inner surface of the bottom wall to the side wall opening edge;
The step of storing the cylindrical unit cell in the inner space of the one case member filled with the fluid heat transfer member so that the cylinder axis is along the inner surface of the bottom wall of the one case member. When,
Sealing the opening of the one case member with another case member;
With
The filling amount of the heat transfer member having fluidity to the internal space of the one case member is such that when the unit cell is accommodated, the heat transfer member having the fluidity has a side wall opening edge of the one case member. Is an amount that does not leak beyond
After performing the sealing step, the unit cell is configured such that each part of both cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member, and at least a part of the remaining part is The battery pack manufacturing method, wherein the battery pack is not in contact with the heat transfer member. A step of preparing a bowl-shaped case member;
A step of storing a cylindrical unit cell with respect to the internal space of the one case member so that a cylindrical axis thereof is along the inner surface of the bottom wall of the one case member;
Filling the internal space of the one case member containing the unit cell with a heat transfer member having fluidity over a range from the inner surface of the bottom wall to the side wall opening edge;
Sealing the opening of the one case member with another case member;
With
After performing the sealing step, the unit cell is configured such that each part of both cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member, and at least a part of the remaining part is The battery pack manufacturing method, wherein the battery pack is not in contact with the heat transfer member. The battery pack manufacturing method according to claim 8 or 9, wherein the heat transfer member is filled and formed only in an internal space of the one case member after performing the sealing step. Method. One cylindrical end of the unit cell is provided with a pole terminal, and a lead plate is connected to the pole terminal,
The lead plate is at least partially covered with the heat transfer member after the unit cell is stored in the internal space of the one case member and the heat transfer member is filled. The manufacturing method of the battery pack in any one of Claims 8-10. The unit cell is accommodated in an internal space of the one case member in a state of being held by a battery holder,
The battery holder is provided with a window,
9. The unit cell according to claim 8, wherein each part of the cylinder ends and a part of the cylinder outer peripheral surface are in close contact with the heat transfer member through a window portion in the battery holder. Item 12. A method for producing a battery pack according to any one of Items 11 to 10.

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