Patent Application
20120308848
The present invention relates to a battery pack that includes a battery block including a plurality of rechargeable base batteries accommodated in a battery holder, a heat-generating component connected to the batteries of this battery block, and an exterior case accommodating the battery block and the heat-generating component, and in particular to a battery pack that can efficiently dissipate heat from the heat-generating component.
A battery pack that includes a number of base batteries are connected to each other in series can increase the output voltage. Also, a battery pack that includes a number of base batteries are connected to each other in parallel can increase the output current. These battery packs have heat-generating components including transistors such as FET, and diodes. For this reason, it is important for these battery packs to efficiently dissipate the heat from the heat-generating components. That is because an abnormal temperature rise of heat-generating component may cause a failure of an element in the battery pack. Also, an abnormal temperature rise of heat-generating component may compromise proper operation of an element in the battery pack.
A battery pack has been developed which includes a metal chassis arranged in an exterior case, and heat-generating components attached onto this metal chassis in order to cool the heat-generating components (see Patent Literature 1).
As shown in
In the thus-constructed battery pack, since the heat-generating components are directly attached onto the metal chassis, there is a disadvantage that time and effort are required to assemble the inner case. The reason is that, after the rechargeable batteries are accommodated in the inner pack, the heat-generating components such as diode and FET connected to leads are attached to the metal chassis portions, which cover the inner pack portion. That is, since the heat-generating components cannot be coupled to the inner pack portion into an integral structure, the inner pack portion is necessarily connected through the leads to the heat-generating components, which are attached to the metal chassis portions. As a result, there is a disadvantage that time and effort are required for this connecting process.
The inventors have developed a battery pack circuit shown in
In the aforementioned battery pack, in order to dissipate the heat from the heat-dissipating plate to the outside, it is necessary to arrange the metal plate with a large area on an interior surface of the exterior case. Accordingly, there is a disadvantage that this battery pack will be complicated and require time and effort when assembled. In addition, since the metal plate is heated by the heat-generating components, there is another disadvantage that it may be difficult to efficiently cool the base batteries, which are arranged to inside the metal plate. In the case where a lead plate is opposed to an interior surface of the exterior case, the lead plate is surely electrically insulated from the metal plate. As a result, a disadvantage will arise that the construction of this battery pack is further complicated. In addition, since the main circuit board 86 overlaps the sub circuit board 87, the heat-generating components mounted on these boards are arranged in proximity to each other. Accordingly, heat is likely to locally generate from this overlapping part. As a result, there is a problem that the heat may not be sufficiently dissipated if heat conducting efficiency is sufficiently high.
The present invention has been developed for solving the disadvantages. It is an object of the present invention to provide a battery pack that can efficiently cool heat-generating components, and can be simply, easily and efficiently assembled.
To achieve the above object, a battery pack according to a first aspect of the present invention includes a battery block 10, a main circuit board 40, a heat-generating component 41, a plate-shaped heat-dissipating block 42, and an exterior case 30. The battery block 10 includes a plurality of base batteries 11, and a battery holder 12 having battery accommodation portions 13. Each of the battery accommodation portions 13 accommodates corresponding one of the plurality of base batteries 11. The main circuit board 40 is connected to the base batteries 11 of the battery block 10. The heat-generating component 41 is connected to the main circuit board 40. The plate-shaped heat-dissipating block 42 is thermally connected to the heat-generating component 41. The exterior case 30 accommodates the heat-dissipating block 42 and the battery block 10. The exterior case 30 includes two opposed surface plates and side walls, and has a box shape. The side walls close peripheral parts of the surface plate 33. The width of the box shape is larger than the thickness of the box shape. The heat-dissipating block 42 is spaced away from the battery block 10 in the exterior case 30 so that the heat-dissipating block 42 does not overlap the battery block 10. The heat-dissipating block 42 is arranged in parallel to the surface plate 33 in the exterior case 30. An opposed surface of the heat-dissipating block 42 opposed to the surface plate 33 is thermally connected to the surface plate 33. Heat generated by the heat-generating component 41 can be conducted to the heat-dissipating block 42 so that the heat can be dissipated from the surface plate 33. According to this construction, the heat-dissipating block can be directly thermally connected to the surface plate of the exterior case. As a result, the exterior case itself can be used for heat dissipation. Therefore, there is an advantage that the heat-dissipating mechanism can be simplified.
In a battery pack according to a second aspect of the present invention, the heat-dissipating block 42 can be arranged on the longitudinal end side of a plurality of the battery blocks 10.
In a battery pack according to a third aspect of the present invention, the heat-dissipating block 42 can be a metal block having a thickness of not less than 5 mm. A block recessed portion 44 can be formed in the surface of the heat-dissipating block 42. The heat-generating component 41 can be arranged in and thermally connected to this block recessed portion 44. According to this construction, the heat-dissipating block is thick so that thermal capacity can be increased, and the heat-generating component is enclosed by the block recessed portion. As a result, heat can be efficiently dissipated from the heat-generating component through three enclosing surfaces.
In a battery pack according to a fourth aspect of the present invention, the main circuit board 40 can be orientated opposed to the recessed portion surface side of the heat-dissipating block 42 where the block recessed portion 44 is formed. The main circuit board 40 can be orientated so that the heat-generating component 41 mounted surface of the main circuit board 40 is opposed to the recessed portion surface side of the heat-dissipating block 42. The heat-generating component 41 is mounted on this heat-generating component 41 mounted surface. According to this construction, the heat-generating component mounted to the main circuit board is arranged in and can be thermally connected to the block recessed portion of the heat-dissipating block.
In a battery pack according to a fourth aspect of the present invention, the block recessed portion 44 of the heat-dissipating block 42 can be filled with thermally conductive paste 45. According to this construction, since the block recessed portion is filled with the thermally conductive paste so that an air layer can be eliminated between the heat-generating component and the block recessed portion. As a result, a thermally insulating layer can be eliminated. Therefore, the heat-generating component can be thermally connected to the block recessed portion.
In a battery pack according to a fifth aspect of the present invention, the heat-generating component 41 can include a diode that is serially connected to the base battery 11. This diode can be arranged in the block recessed portion 44 of the heat-dissipating block 42. According to this construction, since a high-heat-generating diode is arranged in the block recessed portion of the heat-dissipating block, the heat can be effectively dissipated.
In a battery pack according to a sixth aspect of the present invention, a transistor can be provided as the heat-generating component 41, and be mounted to the main circuit board 40. The main circuit board 40 can be orientated so that the transistor-mounted surface of the main circuit board 40 is opposed to the block recessed portion 44 surface of the heat-dissipating block 42. The transistor can be mounted on the transistor-mounted surface. The transistor can be arranged between the main circuit board 40 and the heat-dissipating block 42. The part between the main circuit board 40 and the heat-dissipating block 42 can be filled with thermally conductive paste 45 so that the transistor can be thermally connected to the heat-dissipating block 42 and the main circuit board 40.
In a battery pack according to a seventh aspect of the present invention, the surface plate 33 of the exterior case 30 can have a heat-dissipating block contact recessed portion 47 that is arranged on the surface side of the surface plate 33 in a thermal connection area. The interior surface of the surface plate 33 in the thermal connection area is thermally connected to the heat-dissipating block 42. A plurality of block heat-dissipating fins 48 can be arranged in the heat-dissipating block contact recessed portion 47. The protruding end surfaces of the block heat-dissipating fins 48 can be arranged coplanar with or inside the non-recessed portion surface that is arranged around the periphery of the heat-dissipating block contact recessed portion 47. According to this construction, the surface area can be increased by the block heat-dissipating fins, which protrude outward of the exterior side of the thermal connection area, so that the heat dissipation can be improved. In addition, since the height of the block heat-dissipating fins is the same as or lower than parts around the periphery of the heat-dissipating block contact recessed portion, it is possible to avoid that the block heat-dissipating fins protrude from the exterior case surface. Therefore, there is an advantage that the exterior case can be small.
In a battery pack according to an eighth aspect of the present invention, the battery block 10 can include lead plates 20 that are arranged at positions opposed to the interior surface of the surface plate 33 of the exterior case 30, and is electrically connected to end terminals of the base batteries 11. The lead plate 20 is thermally connected to the interior surface of the surface plate 33 so that heat is thermally conducted from the base batteries 11 through the lead plates 20 to the surface plate 33. According to this construction, since the lead plate and the surface plate of the exterior case 30 can serve as heat-dissipating member, another heat-dissipating member such as heat sink can be smaller or be eliminated.
In a battery pack according to a ninth aspect of the present invention, the surface plate 33 can have a lead protruding portion 24 that is arranged in a lead heat-dissipating area. The interior surface of the surface plate 33 in the lead heat-dissipating area can be thermally connected to the lead plates 20. Heat-dissipating fins 35 can be arranged on the surface side of the surface plate 33 in the exterior side of the lead protruding portion 24. The protruding end surfaces of the heat-dissipating fins 35 can be arranged coplanar with or inside the surface of the exterior part corresponding to the non-protruding portion surface that is arranged around the periphery of the lead protruding portion 24. According to this construction, the surface area can be increased by the lead heat-dissipating fins, which protrude outward of the exterior side of the lead heat-dissipating area, so that the heat dissipation can be improved. In addition, since the height of the lead heat-dissipating fins is the same as or lower than parts around the periphery of the lead protruding portion, it is possible to avoid that the lead heat-dissipating fins protrude from the exterior case surface. Therefore, there is an advantage that the exterior case can be small.
In a battery pack according to a tenth aspect of the present invention, the battery holder 12 can include a peripheral-wall-shaped lead guiding portion 22 for positioning the lead plate 20 in an attachment position. The lead guiding portion 22 partially overlaps an opening plane of at least one of the plurality of the battery accommodation portions 13. According to this construction, since the lead guiding portion for positioning the lead plate can serve as a temporarily holding portion for temporarily holding the base batteries to the battery holder, the battery holder can be simplified.
In a battery pack according to an eleventh aspect of the present invention, the battery holder 12 can further include a temporarily holding portion 14 that partially overlaps an opening plane of another of the plurality of the battery accommodation portions 13 that is located inside the peripheral wall of the lead guiding portion 22 and is not partially overlapped by the lead guiding portion 22, The lead plate 20 can have a temporarily holding opening 23 that is formed at a position corresponding to the temporarily holding portion 14 and in a size capable of receiving the temporarily holding portion 14. According to this construction, when the temporarily holding portion is inserted in the temporarily holding opening, it is possible to avoid that the temporarily holding portion interferes with the lead plate. Accordingly, the lead plate can be brought into tight contact with the base battery. In addition, the lead plate can be positioned by using the temporarily holding portion. Therefore, there is an advantage that it is possible to improve workability in battery pack assembling process and positioning accuracy of lead plate.
In a battery pack according to a twelfth aspect of the present invention, a plurality of lead contact protruding portions 24 can protrude toward the battery block 10 from a surface of the surface plate 33 opposed to the battery block 10. The lead contact protruding portion 24 has a height and shape which can be fitted into the peripheral wall of the lead guiding portion 22, and has a temporarily holding insertion opening 26 that is opened at a position opposed to the temporarily holding portion 14. According to this construction, when fitted into the lead guiding portion, the lead contact protruding portion is positioned in place. In addition, when arranged in the peripheral wall of the lead guiding portion, the lead plate is brought into tight contact with the lead contact protruding portion. As a result, heat can be thermally conducted from the base battery to the surface plate through the lead plate. Therefore, it is possible to efficiently dissipate the heat from the surface plate. Since the lead plate and the exterior case can serve as thermally conductive member, it is possible to improve the heat dissipation performance without heat sink or the like that serves only as thermally conductive member. Therefore, the pack can be small, simple, and low cost.
In a battery pack according to a thirteenth aspect of the present invention, the block heat-dissipating fins 48 can be arranged on one of the two opposed surface plates 33. The lead heat-dissipating fins 35 can be arranged on the other one of the two opposed surface plates 33. According to this construction, the front side and the back side of the exterior case can separately serve as heat-dissipating areas for dissipating heat from the battery block and the heat-dissipating block, respectively. As a result, it is possible to prevent that heat from the battery block and heat from the heat-dissipating block are conducted to the same part. Thus, the both sides of the exterior case can be efficiently used. Therefore, it is possible to effective dissipate the heat.
In a battery pack according to a fourteenth aspect of the present invention, a plurality of battery blocks can be provided as the battery block 10. Each of the battery blocks 10 includes a sub circuit board 17 that is connected to the base batteries 11 in the corresponding one of the battery blocks 10. The sub circuit board 17 can be located between the battery blocks 10. The main circuit board 40 can be arranged on the end surface side of the battery blocks 10 and be orientated intersecting with the sub circuit boards 17. According to this construction, since the main and sub circuit boards with heat-generating components are spaced away from each other and do not overlap each other, it is possible to prevent that heat is locally generated. Therefore, there is an advantage that heat can be efficiently dissipated.
In a battery pack according to a fifteenth aspect of the present invention, the exterior case 30 can include a first case portion 31 and a second case 32. Each of the first and second case portions includes the surface plate 33 with a rectangular shape, and a side wall portion 4b that is arranged along in the periphery of the surface plate 33. The first case portion 31 and the second case portion 32 are coupled to each other so that the exterior case 30 accommodates the battery block 10, the main circuit board 40, and the heat-generating component 41.
In a battery pack according to a sixteenth aspect of the present invention, the exterior case 30 can be formed of electrically-insulating resin. According to this construction, the exterior case can be electrically insulative, lightweight and inexpensive. In addition, although the exterior case is formed of resin, which has low thermal conductivity as compared with metal plates, in the case where the exterior case is directly thermally connected to the heat-dissipating block so that a thermally insulating layer such as air layer is eliminated, it is possible to dissipate the heat.
A battery pack according to another aspect of the present invention includes a plurality of battery blocks 10, a main circuit board 40, and an exterior case 30. Each of the plurality of battery blocks 10 includes a plurality of base batteries 11, and a battery holder 12. The battery holder has battery accommodation portions 13. Each of battery accommodation portions 13 accommodates corresponding one of the plurality of base batteries 11. The main circuit board 40 is connected to the base batteries 11 of the battery block 10. The exterior case 30 accommodates the battery blocks 10. The exterior case 30 includes two opposed surface plates 33 and side walls, and has a box shape. The side walls close peripheral parts of the surface plates 33. Each of the battery blocks 10 includes a sub circuit board 17 that is connected to the base batteries 11 in the corresponding one of the battery blocks 10. The main circuit board 40 is arranged along the side-by-side arrangement direction of the battery blocks 10 on the end surface side of the battery blocks 10, and is orientated intersecting with the sub circuit boards 17. According to this construction, since the main and sub circuit boards do not overlap each other, the heat can be efficiently dissipated.
The following description will describe embodiments according to the present invention with reference to the drawings. It should be appreciated, however, that the embodiments described below are illustrations of a battery pack used therein to give a concrete form to technical ideas of the invention, and a battery pack of the invention is not specifically limited to description below. In this specification, reference signs corresponding to components illustrated in the embodiments are added in “Claims” and “Summary” to aid understanding of claims. However, it should be appreciated that the members shown in claims attached hereto are not specifically limited to members in the embodiments. Unless otherwise specified, any dimensions, materials, shapes and relative arrangements of the members described in the embodiments are given as an example and not as a limitation. Additionally, the sizes and the positional relationships of the members in each of drawings are occasionally shown larger exaggeratingly for ease of explanation. Members same as or similar to those of this invention are attached with the same designation and the same reference signs, and their description is omitted. In addition, a plurality of structural elements of the present invention may be configured as a single part that serves the purpose of a plurality of elements, on the other hand, a single structural element may be configured as a plurality of parts that serve the purpose of a single element. Also, the description of some of examples or embodiments may be applied to other examples, embodiments or the like.
The following description will describe a battery pack 100 according to a first embodiment of the present invention with reference to
The illustrated battery pack 100 includes the battery blocks 10, the main circuit board 40, heat-generating components 41, the heat-dissipating block 42, and an exterior case 30. Each of the battery blocks 10 includes a plurality of base batteries 11, which are arranged in place in battery holders 12. The main circuit board 40 is electrically connected to the battery block 10. The heat-generating components 41 are mounted to the main circuit board 40. The heat-dissipating block 42 is thermally connected to the heat-generating components 41. The exterior case 30 accommodates the heat-dissipating block 42 and the battery block 10.
In the exemplary battery pack shown in
In the exemplary battery pack shown in
In exemplary typical installation orientation of the battery pack, one of the surface plates 33 that can be seen in
As shown in
As shown in
The recessed portions 29 are arranged in the location corresponding to the battery blocks 10, which are accommodated in the exterior case. In the exemplary battery pack shown in
As shown in
In the illustrated battery block 10, the battery accommodation portions 13 of the battery holder 12 accommodate the base batteries 11, which are lithium ion batteries. In the battery pack that includes lithium ion batteries as the base batteries, its output can be high relative to its volume and weight. However, instead of lithium ion batteries, lithium-polymer batteries or nickel metal hydride batteries can also be used as the base batteries. The base batteries in the present invention are not limited to lithium ion batteries. Any types of rechargeable batteries may be used as the base batteries in the present invention. In the illustrated battery pack, although cylindrical batteries are used the base batteries, the base batteries can be rectangular batteries. Temperature sensors for detecting temperature are arranged on the base batteries 11. The temperature sensors can be arranged on all of the base batteries. Alternatively, the temperature sensors may detect temperatures of only representative base batteries that are arranged in particular locations. The output sides of the temperature sensors are connected to and monitored by a sub circuit board 17.
The battery holder 12 is formed of an electrically insulating material, preferably of resin. In this embodiment, the base batteries 11 are cylindrical rechargeable batteries. Correspondingly, a plurality of battery accommodation portions 13 are formed in the battery holder 12 and have cylindrical hollow interior space so that the cylindrical base battery 11 can be accommodated in the cylindrical battery accommodation portions 13. The battery accommodation portion 13 entirely surrounds the cylindrical peripheral surface of the cylindrical base batteries 11. In this embodiment, the battery accommodation portions 13 are formed so that the center axes of the cylindrical base batteries in upper and lower rows are deviated (offset) from each other when the cylindrical base batteries 1 are arranged side by side.
Temporarily holding portions 14 are provided for the battery accommodation portions 13. The temporarily holding portions 14 temporarily hold the cylindrical base batteries 11 accommodated in the battery accommodation portions 13, and prevent the base batteries 11 from dropping off. The temporarily holding portions 14 are protrusions that partially overlap from the end surfaces of the hollow battery accommodation portions 13. The end surfaces of the cylindrical base batteries 11 accommodated in the battery accommodation portions 13 come in contact with the protrusions. According to this construction, when accommodated in the battery accommodation portions 13, the cylindrical base batteries 11 can be temporarily held. As a result, it is possible to fasten the lead plates 20 to the temporarily held base batteries 11 by welding, or the like. It is preferable that the temporarily holding portions 14 be arranged on the both sides of the battery accommodation portion 13, which is opened on the right and left sides of the battery holder 12. According to this construction, when the base battery 11 is inserted into the battery accommodation portion 13, this base battery 11 can be held and be prevented from easily dropping off even if the battery block 10 is tilted either rightward or leftward.
The battery holder 12 shown in
In the battery block 10, the battery holder 12 holds the base batteries 11 in a parallel orientation, specifically, in a horizontal orientation in
In the battery block 10, the battery holder 12 holds the base batteries 11 in a parallel orientation, specifically, in a horizontal orientation in
The sub circuit board 17 is fastened to the side surface of each of the battery holders 12, and detects and monitors the battery temperature in corresponding one of the battery blocks 10. The sub circuit board 17 includes a temperature detector circuit that receives the output of the temperature sensors fastened to the base batteries 11. In addition, the sub circuit board 17 can include a current sensor that detects charging/discharging current in corresponding one of the battery blocks 10, a voltage sensor, or a charge/discharge control circuit, if necessary. In this embodiment, the sub circuit board 17 is located between the battery blocks 10. For this reason, relatively low-heat-generating elements are mounted on the sub circuit board 17, while relatively high-heat-generating elements are mounted on the main circuit board 40 discussed later. In this embodiment, the sub circuit board 17 is provided with electronic components that realize a protection circuit for controlling the charging/discharging operation on the base batteries 11.
The sub circuit board 17 is arranged on the left side of the battery holder 12 in
As shown in
In this embodiment, the power supply outputs of the battery blocks 10 are provided through the diodes as discussed above, and are then connected in parallel to each other. Thus, the power supply output of the battery pack is supplied through the output terminals A. Needless to say, however, the outputs of the battery blocks 10 can be serially connected to each other for supplying the output of the battery pack.
In addition, guide ribs 19 are formed of plastic integrally with the first and second holder cases 15 and 16, and hold the sub circuit board 17. The guide ribs 19 protrude alternately from the right and left side surfaces of the battery holder 12. A screw hole for fastening the sub circuit board 17 is opened on the end surface of the guide rib 19. The sub circuit board 17 can be fastened by screwing a fastening screw into the screw hole.
After the cylindrical base batteries 11 are inserted into the battery accommodation portions 13 of the battery holder 12, the lead plates 20 are fastened onto the end terminals, which are exposed on the end surfaces of the base batteries 11. The lead plates 20 serve as members that connect the base batteries 11 in parallel and/or in series to each other with the base batteries 11 being accommodated in the battery holder 12. A thin metal plate is used as the lead plate 20. In the exemplary battery block shown in
The lead guiding portion 22 is arranged along the side surfaces of the battery holder 12, and guides the lead plate 20 to an installation position. The lead guiding portion 22 is formed in a peripheral-wall shape substantially matching with the exterior shape of the lead plate 20. The lead plates 20 can be easily positioned in a process for fastening the lead plates 20 to the base batteries 11 by placing the lead plates 20 inside the peripheral-wall shapes of the lead guiding portions 22. It is preferable that the lead guiding portion 22 also serve as the temporarily holding portion that prevents the base batteries 11 from dropping off. That is, in the case where the lead guiding portions 22 partially protrude toward or overlap the opening surfaces of the battery accommodation portions 13, the partially protruding parts of the lead guiding portions 22 come in contact with the end surfaces of the base batteries 11, which are inserted into the battery accommodation portions 13, so that the base batteries 11 can be prevented from dropping off. In this case, a part that protrudes outward of the battery holder 12 can be small. As a result, the battery holder 12 can be simplified. The lead guiding portion 22 can be an elongated member that has a square shape as viewed in section, for example.
However, all of the temporarily holding portions are not necessarily required to be provided by the lead guiding portions 22. Separately provided temporarily holding portions 14 can be additionally arranged in the battery accommodation portions 13 in which the lead guiding portions are not provided. In this case, one temporarily holding portion 14 can be arranged straddling battery accommodation portions 13 that are located adjacent to each other and are not provided with the lead guiding portions. The one temporarily holding portion 14 overlaps or protrudes toward battery accommodation portions 13 that are located adjacent to each other. Thus, one temporarily holding portion 14 can serve as a temporarily holding member that temporarily holds two battery accommodation portions 13. The one temporarily holding portion 14 can have a disk shape, and be arranged in proximity to the boundary between battery accommodation portions 13 that are located adjacent to each other. Thus, the disk-shaped temporarily holding portion 14 protrudes in the right and left battery accommodation portions 13. Therefore, it is possible to effectively prevent the base batteries 11 from dropping off.
In addition, the height of the temporarily holding portion 14 is larger than the thickness of the lead plate 20, and is preferably the same as or smaller than the height of the lead guiding portion 22. It is preferable that the lead guiding portion 22 and the temporarily holding portion(s) 14 be formed integrally with the battery holder 12 by molding. According to this construction, manufacturing processes can be simplified, and low cost. However, the sectionally rectangular lead guiding portions 22 and the disk-shaped temporarily holding portions 14 may be prepared separately from the battery holders, and be fastened to the side surfaces and the like of the battery holders by an adhesive or the like.
In addition, the temporarily holding portions 14 are arranged in areas that are enclosed by the lead guiding portions 22. That is, since the lead guiding portion 22 serves as temporarily holding portions 14 that temporarily hold base batteries accommodated in battery accommodation portions 13 that are arranged along the lead guiding portion 22, additional temporarily holding portions 14 can be arranged which temporarily hold base batteries accommodated in battery accommodation portions 13 that do not face the lead guiding portion 22, in other words, are not arranged along the lead guiding portion 22 but are arranged inside away from the lead guiding portion 22.
In addition, the lead plates 20 have temporarily holding openings 23 that are formed at the positions corresponding to the temporarily holding portions 14 so that, when the lead plates 20 are fastened, the temporarily holding portions 14 to be located in the lead plates 20 may not interfere with the lead plates 20. According to this construction, since it is avoidable that the lead plate 20 interferes with the temporarily holding portion 14, the lead plate 20 can be brought into tight contact with the end surfaces of the base batteries 11. As a result, it can be ensured that the lead plate 20 can be electrically and thermally conducted to the end surfaces of the base batteries 11. In addition, there is an advantage that, when the temporarily holding portion 14 is inserted into the temporarily holding opening 23, the temporarily holding portion 14 can serve also as a guide for positioning the lead plate 20.
Not an entirely flat surface but a plurality of lead contact protruding portions 24 are formed on an interior surface of the exterior case 30, which accommodates the battery blocks. In other words, the plurality of lead contact protruding portions 24 protrude inward of the back surface of the surface plate 33, and come in contact with the battery blocks 10. The lead contact protruding portion 24 includes a contact flat surface 25 that protrudes toward the battery block 10, as shown in
Also, the exterior case 30 includes first and second case portions 31 and 32. Each of first and second case portions 31 and 32 includes the surface plate 33. When the first and second case portions 31 and 32 are coupled to each other, the surface plates 33 are opposed to each other. The lead contact protruding portions 24 are formed on the interior surface of the surface plate 33 of each of the first and second case portions 31 and 32. According to this construction, for example, the battery blocks 10 are positioned on the first case portion 31 so that the lead contact protruding portions 24 that are formed on the first case portion 31 interior surface can be arranged inside the peripheral-wall shapes of the lead guiding portions 22, and that the lead contact protruding portions 24 that are formed on the interior surface of the second case portion 32 can be arranged inside the peripheral-wall shapes of the lead guiding portions 22 that are arranged on the opposite side of the battery block 10. After that, the first and second case portions 31 and 32 are coupled to each other. As a result, the battery holders 12 can be accurately positioned. In addition, since the battery holders 12 are sandwiched from the both sides between the lead contact protruding portions 24, the battery holders 12 can be securely held. Therefore, it can be ensured that the battery holders 12 can be mechanically stabilized. Additionally, since the lead plates 20 can be brought into tight contact with the lead contact protruding portions 24, it is possible to suppress that a thermally insulating layer such as space (i.e., air layer) is formed between the lead plate 20 and the lead contact protruding portion 24. As a result, heat from the base batteries can be directly thermally conducted to the surface plates 33 through the lead plates 20. Therefore, it is possible to efficiently dissipate the heat from the surface plates 33. According to this construction, since the lead plates 20 and the exterior case 30 can serve as thermally conductive member, it is possible to improve the heat dissipation performance without heat sink or the like that serves only as thermally conductive member. Therefore, the battery pack can be small, simple, and low cost.
In addition, it is preferable that recessed portions be formed in location corresponding to the lead contact protruding portions 24 on the opposite side of the exterior case 30 opposite to the lead contact protruding portions 24, in other words, on the surface side of the exterior case 30 as shown in the cross-sectional view of
As shown in
In addition, it is preferable that the protruding height of the lead heat-dissipating fins 35 be dimensioned so that the lead heat-dissipating fins 35 do not protrude from other parts of the surface plate 33, and extend in the perpendicular direction within the recessed area 34 as shown in the cross-sectional view of
The base batteries 11 in each of the battery blocks 10 accommodated in the exterior case 30 are held with the end surfaces of the base batteries 11 being orientated in parallel to the surface plates 33 of the exterior case 30. According to this arrangement, since the both end surfaces of each of the base batteries 11 face the opposed surface plates 33 of the exterior case 30, it is possible to facilitate heat dissipation through the end surfaces of the base batteries 11 from the both sides of the exterior case 30. In particular, since the both end surfaces of the base batteries 1 are connected to the lead plates 20, which have excellent thermal conductivity, the heat can be conducted from the both end surfaces of the base batteries 1 through the lead plates 20. In addition, the heat from the lead plates 20 can be conducted to the exterior case 30, which faces the surfaces of the lead plates 20. As a result, the heat can be dissipated from the exterior case 30 surfaces.
A plurality of battery blocks 10 are arranged side by aide and are accommodated in the exterior case 30. In the battery pack shown in
The main circuit board 40 includes circuits required for operating the power supply device and their component parts, elements, and the like, such as charging/discharging circuit for controlling charging/discharging current of the battery blocks 10, and the protection circuit. The main circuit board 40 can be formed from a glass epoxy plate or the like. In the main circuit board shown in
The heat-dissipating block 42 is formed of a material having good heat conductivity, and preferably of a plate-shaped metal block. The metal block preferably has a thickness of not less than 5 mm, and is formed of a material having sufficient thermal capacity and thermal conductivity such as aluminum. In the case where the heat-dissipating block 42 is thick as compared with the main circuit board 40, heat can be thermally conducted from the main circuit board 40 and be efficiently dissipated.
The heat-dissipating block 42 is thermally connected to the heat-generating components 41, which are mounted on the main circuit board 40. To achieve this, block recessed portions 44 are formed on the surface of the heat-dissipating block 42 so that the heat-generating components 41 are arranged in the block recessed portions 44. According to this construction, the heat-generating component 44 is enclosed by three enclosing surfaces of the block recessed portion 44. As a result, heat can be efficiently conducted (absorbed) from the heat-generating component 41, and be dissipated from the heat-dissipating block. To achieve this, the main circuit board 40 is orientated so that the heat-generating component 41 mounted surface of the main circuit board 40 is opposed to the recessed portion surface side of the heat-dissipating block 42. The heat-generating component 41 is mounted on this heat-generating component 41 mounted surface. In the heat-dissipating block shown in
In order to thermally connect the heat-dissipating block 42 to the heat-generating components 41, the block recessed portions 44 are filled with thermally conductive paste 45. According to this construction, since the thermally conductive paste 45 is interposed between the heat-generating components 41 and the block recessed portions 44, air layers can be eliminated which have high thermally insulation. As a result, it can be surely maintained that the heat-generating components 41 is thermally coupled to the block recessed portions 44. Silicone resin or the like can be suitably used as the thermally conductive paste 45. The block recessed portion 44 is filled with silicone resin so that the heat-generating component 41 can be completely covered with this silicone resin. Alternatively, the heat-generating component can be thermally connected to the surface of the heat-dissipating block 42 through mica, which has electrical insulation but good thermal conductivity, or an electrically-insulating but thermally conductive sheet formed of plastic. In the heat-dissipating block shown in
As shown in
The heat-dissipating block 42 and the main circuit board 40 are spaced away from the battery blocks 10 in the exterior case 30 so that the heat-dissipating block 42 and the main circuit board 40 do not overlap the battery blocks 10. That is, as shown in
In particular, the heat-dissipating block 42 is arranged in the exterior case 30 in parallel to the surface plate 33 so that a surface of the heat-dissipating block 42 that is opposed to this surface plate 33 is thermally connected to this surface plate 33. According to this arrangement, heat can be absorbed from the heat-generating components 41 to the heat-dissipating block 42, and this heat can be dissipated from the surface plate 33. Since the heat-dissipating block 42 is directly thermally connected to this surface plate 33 of the exterior case 30, the exterior case 30 itself can be used for heat dissipation. Therefore, there is an advantage that a heat sink or the like for heat dissipation can be simplified and small, or omitted.
In addition, the main circuit board 40 is spaced away from, and does not overlap the sub circuit boards 17 each of which is provided for corresponding one of the battery blocks. Specifically, as shown in
The surface plate 33 of the exterior case 30 has the heat-dissipating block contact recessed portion 47 that is arranged on the surface side of the surface plate 33 in a thermal connection area. The interior surface of the surface plate 33 in the thermal connection area is thermally connected to the heat-dissipating block 42. It is more preferable that a plurality of block heat-dissipating fins 48 be arranged in the heat-dissipating block contact recessed portion 47 as shown in
It is preferable that the block heat-dissipating fins 48 be formed on a part of the surface plate 33 that is different from a part of the surface plate 33 where the lead heat-dissipating fins 35 are formed. That is, the block heat-dissipating fins 48 are arranged on one of the two opposed surface plates 33, and the lead heat-dissipating fins 35 are arranged on the other one of the two opposed surface plates 33. According to this construction, heat-dissipating areas can be separately provided for battery blocks and for the heat-dissipating block. As a result, it is possible to prevent that heat is locally generated in a particular area. In addition, since the both sides of the exterior case 30 can be efficiently used as the heat-dissipating areas, it is possible to effectively dissipate heat. In other words, in the battery pack shown in
Since the battery pack includes the aforementioned heat-dissipating construction, it is possible to efficiently dissipate heat without additional high heat-dissipating structure such as large heat sink. Therefore, it is possible to provide a battery pack that can be stably used as high-output power supply device. In particular, even in the case where the exterior case 30 is a case formed of resin, which has low thermal conductivity as compared with metal cases, the heat-dissipating construction according to the present invention can achieve sufficient heat-dissipating performance. In this case, there is a great advantage from viewpoint of cost.
A battery pack according to the present invention can be suitably used as a backup power supply device that can be installed to computer server racks, a backup power supply device for wireless base stations such as mobile phone base stations, an electric power storage device used together with solar batteries, and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-017500 | Jan 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/051475 | 1/26/2011 | WO | 00 | 7/27/2012 |
