Patent Application
20130273404
1. Technical Field
The present invention relates to a battery pack including a battery assembly constructed of a plurality of rectangular battery cells and separators that are alternately arranged on each other, and a vehicle using this battery pack. The present invention more particularly relates to a battery pack to be installed on an electric vehicle such as hybrid car and electric car and suitable as a power supply for supplying electric power to an electric motor for driving the vehicle, and a vehicle using this battery pack.
2. Description of the Related Art
Large-capacity power supply devices to be used in vehicles include a number of battery cells that are serially connected to each other to increase the output voltage whereby increasing the output electric power. A power supply device has been developed which includes a battery assembly constructed of a number of battery cells that have not a cylindrical shape but a rectangular thin box shape and are arranged side by side in the thickness direction whereby increasing the volumetric charge density of the power supply device (see Japanese Patent Laid-Open Publication No. JP 2010-8688 A).
In this type of power supply device, in the case where the rectangular battery cell includes an exterior container formed metal, the potential of the exterior container is not always zero. For this reason, electrically insulating separators are interposed between the adjacent rectangular battery cells in order to prevent short circuit between the battery cells when the battery cells are arranged side by side in the thickness direction. The separators are formed of resin such as plastic, and have a size substantially equal to the rectangular battery cell.
In the known power supply device, the separators and the rectangular battery cells are alternately arranged on each other one by one. Accordingly, there is a problem that this assembly work is a burden.
In addition, each of the rectangular battery cells includes terminals on its upper surface. After the separators and the rectangular battery cells are alternately arranged on each other so that the battery assembly is constructed, it is necessary to connect the terminals to each other through bus bars. To achieve this, the terminals are formed in a threaded cylindrical shape, while the bus bars have through holes through which the threaded cylindrical-shaped terminals can pass. However, if the rectangular battery cells are deviated from their predetermined positions that will agree with the through holes of the bus bars, the terminals cannot be inserted into the through holes of the bus bars. The positional deviation may prevent the connection between the terminals and the bus bars.
On the other hand, a battery pack has been developed which includes a separator that is integrally formed corresponding to two separators so as to cover two rectangular battery cells on one surface of the separator with the two rectangular battery cells being arranged adjacent to each other in the width direction of the rectangular battery cell (Japanese Patent Laid-Open Publication Nos. JP 2009-272234 A and JP 2010-55908 A). This separator can simplify the assembly work to a certain degree. However, it is still necessary to arrange the separators on the rectangular battery cell in the alternate arrangement direction. As for the alternate arrangement, the burden of the assembly work cannot be reduced. In addition to this, the alternate arrangement of a number of the battery cells and separators may cause the positional deviation.
The present invention is aimed at solving the above problem, and its main object is to provide a power supply device for easy separator assembly and arrangement.
To achieve the above object, a battery pack according to a first aspect of the present invention includes a plurality of rectangular battery cells and a separator unit. The rectangular battery cells have a rectangular box exterior shape the thickness of which is smaller than the width. The separator unit prevents the main surfaces of the plurality of rectangular battery cells from contact with each other, and electrically insulates the rectangular battery cells from each other. The rectangular battery cells are arranged side by side in the thickness direction of the battery cells as a battery assembly with the main surfaces facing to each other. The separator unit includes a first subseparator. The first subseparator includes a plurality of spacer plates and a support portion. The spacer plates have a size substantially equal to the main surface of the rectangular battery cell. The support portion supports the plurality of spacer plates with gaps being formed between the spacer plates in the width direction of the rectangular battery cells. The gap between the spacer plates is dimensioned so that the rectangular battery cell can be inserted into the gap. According to this construction, since a plurality of spacer plates of the first subseparator are previously supported, the battery assembly can be easily assembled by inserting the rectangular battery cells into the gaps between the spacer plates. In addition to this, since the first subseparator is previously accurately shaped, the spacer plates can be accurately positioned irrespective of the alternate arrangement of the rectangular battery cells. Therefore, there is an advantage that bus bars, and the like can be easily coupled to the battery cells.
In a battery pack according to a second aspect of the present invention, the support portion can cover the bottom surface of the battery assembly. According to this construction, there is an advantage that the rectangular battery cells can be easily inserted into the support portion.
In a battery pack according to a third aspect of the present invention, the support portion can at least partially cover the upper surface of the battery assembly. According to this construction, there is an advantage that the spacer plates can be easily inserted into gaps between the rectangular battery cells that are arranged in place.
In a battery pack according to a fourth aspect of the present invention, bus bars can be further provided which connect terminals on the upper surfaces of the rectangular battery cells to each other. The separator unit can further include an electrically insulating second subseparator that holds the bus bars at predetermined positions, and is arranged on the upper surface of the battery assembly. The terminals can be connected to each other through the bus bars by coupling the second subseparator to the first subseparator. According to this construction, the bus bar can be positioned by the second subseparator. When the second subseparator is coupled to the separator, the bus bars can connect the terminals to each other. Therefore, there is an advantage that the bus bars and the terminals can be very easily connected to each other.
In a battery pack according to a fifth aspect of the present invention, the second subseparator can include a second subseparator main portion, and a bus bar portion. The bus bar portion is arranged on the upper surface of the second subseparator main portion, and provided separately from the second subseparator main portion. The bus bars are held by the bus bar portion. According to this construction, since the second subseparator is constructed of the separated parts including the bus bar portion, there is an advantage that the bus bars can be easily and safely coupled to the rectangular battery cells. The second subseparator may include a second subseparator main portion that extends in the central part on the upper surface of the battery assembly in the width direction, and first and second bus bar portions that are arranged on the right and left side of the second subseparator main portion and hold the bus bars.
In a battery pack according to a sixth aspect of the present invention, the bus bar portion can be constructed of a plurality of separated bus bar block parts. According to this construction, even in the case where a number of rectangular battery cells are arranged in the width direction, the bus bar portion can be constructed of an easy-to-handle number of separated parts. Therefore, there is an advantage that the bus bar can be more easily coupled to the battery cells.
In a battery pack according to a seventh aspect of the present invention, the second subseparator main portion can be constructed of a plurality of separated subseparator block parts. According to this construction, even in the case where a number of rectangular battery cells are arranged in the width direction, an easy-to-handle number of spacer plates can be supported by the separated subseparator block parts. Therefore, there is an advantage that the rectangular battery cells can be more easily inserted into the gaps between the spacer plates.
In a battery pack according to an eighth aspect of the present invention, the bus bars can be integrally formed with the second subseparator by insert molding. According to this construction, there is an advantage that the bus bars can be firmly held in the second subseparator.
In a battery pack according to a ninth aspect of the present invention, the bus bars can be integrally formed with the second subseparator by outsert molding. According to this construction, there is an advantage that the bus bars can be held in the second subseparator at low cost.
In a battery pack according to a tenth aspect of the present invention, a pair of end plates and bind bars can be further provided. The end plates are arranged on the end surfaces of the width direction of the rectangular battery cells and the spacer plates, which are alternately arranged so that the spacer plates are sandwiched between the battery cells, of the battery assembly. The metal bind bars securely couple the end plates, which are arranged on the end surfaces of the battery assembly, to each other. According to this construction, when the end plates are coupled to each other through the bind bars, the battery assembly can be securely held.
A vehicle according to an eleventh aspect of the present invention includes the aforementioned power supply device.
The above and further objects of the present invention as well as the features thereof will become more apparent from the following detailed description to be made in conjunction with the accompanying drawings.
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 and a vehicle including this battery pack to give a concrete form to technical ideas of the invention, and a battery pack and a vehicle including this battery pack of the invention are not specifically limited to description below. Furthermore, 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.
As shown in
A safety valve 1E is arranged in the central part of the sealing plate 1B.
When an internal pressure in the exterior container 1A rises, the safety valve will open so that gas can be discharged. In order that gas can safely be exhausted, a duct (not shown) is connected to the safety valve 1E. In addition, the surfaces except the top surface of the rectangular battery cell 1 are subjected to an electrically insulating process. Specifically, the surfaces other than the top and bottom surfaces of the rectangular battery cell 1 are covered with a covering film. The rectangular battery cells 1 are lithium-ion rechargeable batteries. However, the battery cells may be nickel metal hydride battery batteries or nickel-cadmium batteries.
The pair of end plates 3 are arranged on the both end surfaces of the battery assembly 10 of the rectangular battery cells 1 with the separator plates 2 being sandwiched between the battery cells. When the pair of end plates 3 are firmly coupled to each other, the battery assembly 10 is securely held between the pair of end plates. The end plate 3 shown in
The bind bars 4 serves as fasteners for fastening the rectangular battery cells 1. In this embodiment, the both end parts of the elongated metal plate are bent so that metal plate has a rectangular U shape as viewed from the top side.
The both end parts serve as bent parts 41. The bent part 41 has the slit 42 into which the protrusion 33 of the end plate 3 can be inserted. In addition, the bind bars have pin openings 43 into which the positioning pins 34 on the end plate 3 can be inserted.
Thus, the bind bars 4 couple the end plates 3 to each other, and securely hold the side surfaces of the battery assembly so that the end plates are in press contact with the both end surfaces of the battery assembly including the battery cells 1 with the separator plates 2 being sandwiched between the battery cells. Specifically, when the protrusions 33 of the end plates 3 engage with the slits 42 of the bent parts 41 of the bind bars 4, the rectangular battery cells 1 are arranged in the width direction, and brought in press contact with the end plates 3 with the separator plates 2 being sandwiched between the rectangular battery cells 1.
The engagement structure between the bind bar 4 and the end plate 3 is not limited to this. Known engagement structures can be suitably used including a threaded-engagement structure that uses a screw so that the bind bar is fastened to the end plate.
In the battery assembly 10, the separator plates 2 are sandwiched between the rectangular battery cells 1, which are arranged in the width direction. The plurality of rectangular battery cells 1 are arranged side by side in the thickness direction of the battery cells with the main surfaces facing to each other. The separator unit is arranged between the main surfaces of the rectangular battery cells 1 and prevents the rectangular battery cells from contact with each other whereby electrically insulating the rectangular battery cells 1 from each other. The spacer plates 2 are not individually inserted into gaps between the rectangular battery cells, but a separator unit 20 is used which includes the spacer plates that are integrally formed. The separator unit 20 is constructed of a plurality of separated subseparators. The separator unit according to the first embodiment shown in
The first subseparator 21 is constructed of a plurality of spacer plates 2, and a support portion 23. The spacer plates are arranged substantially in parallel to each other, and spaced substantially at a fixed interval away from each other. The support portion supports the spacer plates 2. Each of the spacer plates 2 corresponds to the known single separator, and can be inserted into the gap between rectangular battery cells 1 so that the battery cells are electrically and thermally insulated from each other. The spacer plates 2 have a size substantially equal to a main surface of the rectangular battery cell. The spacer plate 2 is not flat but has a shape that is obtained by connecting rectangular U shapes that are alternately orientated frontward and rearward as viewed the side of the spacer plate so that gaps can be formed between the rectangular battery cells 1 and the spacer plate 2 when the battery cells are in contact with the separator plate. Accordingly, cooling gas such as air can pass through the gaps so that the rectangular battery cells 1 can be cooled. In the case where the spacer plate 2 is formed in a shape that is obtained by deforming a plate shape, the cooling gaps for cooling the battery cells can be formed between the spacer plates 2 and the rectangular battery cells 1 when the rectangular battery cells 1 are alternately arranged on the spacer plates. In addition, a blower mechanism (not shown) is provided as a cooling mechanism that forcedly blows cooling gas to cool the rectangular battery cells 1 of the battery assembly 10.
The first subseparator 21 may serve as a cooling plate. In other words, instead of the air cooling system, a system may be used which includes the cooling plate as the first subseparator, which is in contact with the bottom surface of the battery assembly 10 and is cooled by coolant or the like so that the battery assembly 10 directly is cooled. In this case, the cooling plate can be formed as the base portion 21A on which the battery cells are be arranged in the width direction. In the case where this coolant-type cooling system is used, the air-cooling gaps can be omitted. For this reason, the flat spacer plates 2 can be used which are inserted into gaps between the rectangular battery cells 1, and electrically and thermally insulate the rectangular battery cells 1 from each other.
The gap between the spacer plates 2 of the support portion 23 for supporting the spacer plates 2 is dimensioned so that the rectangular battery cell 1 can be inserted into the gap. In this embodiment, the support portion 23 is dimensioned to cover the bottom surface of the battery assembly 10. The spacer plates 2 of the first subseparator 21 are inserted into the gaps between the rectangular battery cells 1 from top side, right side or left side. Thus, the battery assembly 10 is constructed. It is preferable that the first subseparator 21 be integrally formed of an electrically insulating material such as resin. Accordingly, the rectangular battery cells 1 can be accurately positioned and arranged in the width direction. In particular, in the case where the support portion 23 is arranged on the bottom surface of the rectangular battery cell 1, the rectangular battery cells 1 can be aligned at the same vertical position so that the sealing plates 1B as the top surfaces of the battery cells can be arranged coplanar. As a result, the bus bars BB can be stably coupled to the battery cells. The known battery assembly does not include a member that supports the rectangular battery cells and restricts vertical positional deviation of the battery cells. For this reason, the top and bottom surfaces of the battery cells may not be arranged coplanar. As a result, it is not easy to stably couple the bus bars to the battery cells and to bring the bottom surfaces of the battery cells in the same contact condition when the battery cells are in contact with the cooling plate. In particular, in the case where the known battery pack is used for vehicles, although the battery cells are held by the bind bars, the battery cells may be deviated in the vertical direction. If the battery pack is used for a long time, the reliability of the battery pack may decrease. Contrary to this, since the rectangular battery cells 1 according to the first embodiment are arranged on the upper surface of the support portion 23, the possibility of such positional deviation is almost zero. Therefore, there is an advantage that the rectangular battery cells 1 can be stably held at the same vertical position for a long time.
In addition, since the main surface of the rectangular battery cell 1 is sandwiched between the spacer plates 2, the movement of the battery cell is restricted in the width direction. Also, expansion of the rectangular battery cell 1 can be suppressed. Also, it is not necessary to alternately arrange the separators on the rectangular battery cells 1 one by one when the battery pack is assembled. Therefore, the battery pack can be easily and quickly assembled.
The lower-surface of the battery assembly 10 is supported by the first subseparator 21, while the upper surface of the battery assembly 10 is covered by the second subseparator 22. The second subseparator 22 covers the upper surfaces of the rectangular battery cells 1, and holds the bus bars BB, which connect the terminals of the adjacent rectangular battery cells 1 to each other. The second subseparator 22 is fastened to the first subseparator 21. Thus, the top and bottom surfaces and main surfaces of the rectangular battery cells 1 can be protected. The side surface sides of the battery assembly 10 are exposed. Accordingly, cooling gas can pass through the gaps between the rectangular battery cells 1 through the side surface sides so that the battery assembly 10 can be cooled. The first subseparator 21 can be fastened to the second subseparator 22 by screws, fit-in structures, an adhesive, or the like.
It is preferable that the bus bar BB be previously held by the second subseparator 22. Accordingly, when the second subseparator 22 is coupled and fastened to the first subseparator 21, the bus bars BB can be coupled to the battery cells. Since the rectangular battery cells 1 are positioned and held by the first subseparator 21, while the bus bars BB are positioned and held by the second subseparator 22, when the first and second subseparators are fastened to each other, the bus bars BB can be arranged at their predetermined positions of the rectangular battery cells 1. Therefore, there is an advantage that the burden of the coupling work of the bus bars BB can be substantially reduced. The bus bar BB can be securely held to the second subseparator 22 for example by insert molding or outsert molding.
The second subseparator 22 has gas exhaust openings 24 that are arranged along the center line at the positions corresponding to the safety valves 1E of the rectangular battery cells 1 as shown in
In the foregoing embodiment, it has been illustratively described that the first subseparator 21 securely holds the spacer plates 2 to be inserted into the gaps between the rectangular battery cells 1. However, the present invention is not limited to this. The second subseparator can securely hold the spacer plates.
In the second embodiment, it has been described that the second subseparator 22 is integrally formed. However, the second subseparator can be constructed of a plurality of separated members.
Each of the first and second bus bar portions 26 and 27, and the second subseparator main portion 25 is not always required to be integrally formed. Each of the first and second bus bar portions, and the second subseparator main portion can be constructed of separated parts.
Although it has been illustratively described that the bus bars are held in the bus bar block parts 29 by insert molding in the embodiment shown in
As discussed above, since the separator unit is used which includes the spacer plates 2 that are previously positioned in the separator unit, the assembly work efficiency can be improved. In addition, the rectangular battery cell can be reliably and easily positioned. As a result, there is an advantage that the bus bars, and the like can be easily coupled to the battery cells.
With reference to
A battery pack according to the present invention can be suitably used as power supply devices of plug-in hybrid vehicles and hybrid electric vehicles that can switch between the EV drive mode and the HEV drive mode, electric vehicles, and the like. A vehicle including this battery pack according to the present invention can be suitably used as plug-in hybrid vehicles, hybrid electric vehicles, electric vehicles, and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-244858 | Oct 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/074945 | 10/28/2011 | WO | 00 | 6/3/2013 |
