Patent Application
20120301769
1. Field of the Invention
The present invention relates to a power source apparatus to supply electric power that is used as a power source for an electric motor that drives a vehicle such as a hybrid vehicle (HV, hybrid electric vehicle, HEV, hybrid car), a fuel cell vehicle (FCV, fuel cell electric vehicle, FCEV, fuel cell car), or an electric vehicle (EV, electric automobile, electric car), or is used to store solar cell (solar battery) electric power, and to a vehicle equipped with that power source apparatus.
2. Description of the Related Art
High power output is required from a power source apparatus that powers a motor to drive a vehicle, is charged by solar cells to supply power at night, or supplies power during daytime periods of high power demand. The power source apparatus has a plurality of batteries connected in series to increase output voltage. For these types of applications, a power source apparatus has been developed that has a plurality of rectangular batteries stacked together and configured with adjacent batteries connected in series to increase the output voltage.
Refer to Japanese Laid-Open Patent Publication 2010-153141.
The power source apparatus cited in JP 2010-153141 has a plurality of rectangular batteries with insulating separators disposed between the batteries. The insulating separators insulate adjacent rectangular batteries that are stacked together. A configuration that stacks a plurality of (series-connected) rectangular batteries in a battery block generates potential difference between the external cases of adjacent rectangular batteries. Accordingly, it is necessary to insulate adjacent rectangular batteries when they are stacked together. To insulate adjacent rectangular batteries, insulating separators formed from insulating material such as plastic are disposed between the batteries. Specifically, a battery block is made by alternately stacking rectangular batteries and insulating separators. This battery block structure requires the rectangular batteries and insulating separators to be disposed in fixed positions and held together in a stacked assembly. If the relative position between rectangular batteries and insulating separators shifts and the external cases of adjacent batteries touch, high short circuit current will flow that damages the batteries and prevents safe operation. Consequently, it is necessary to accurately dispose the insulating separators between rectangular batteries in a manner that will not shift position. As a result, this system has the drawbacks that stacking many rectangular batteries together to assemble a battery block is troublesome, the number of component parts is large, and assembly cost is high. Furthermore, when used over a long period, effects such as vibration can shift the relative position of rectangular batteries and insulating separators to generate high short circuit current flow through the batteries.
The present invention was developed with the object of correcting the drawbacks described above. Thus, it is a primary object of the present invention to provide a power source apparatus to supply electric power and vehicle equipped with the power source apparatus that can attain a high margin of safety while reducing assembly cost.
The power source apparatus to supply electric power of the present invention is provided with a battery block 3 having a plurality of rectangular batteries 1 disposed in a stacked configuration with conducting external cases 11 insulated by insulating layers 2, 42, 52, 62, a cooling plate 4 disposed at the bottom of the battery block 3 in a manner that thermally couples with each rectangular battery 1 and forcibly cools each battery 1 from its bottom surface, and a cooling mechanism 5 that cools the cooling plate 4. The insulating layers 2, 42, 52, 62 are formed as a unit with each external case 11 and have a fit-together structure that enables the batteries 1 to be stacked in fixed positions. Each rectangular battery 1 is configured with insulating layers 2, 42, 52, 62 as a single-piece battery module 10, and a plurality of battery modules 10 are stacked to make a battery block 3.
The power source apparatus described above attains a high safety margin while reducing assembly cost. This is because each rectangular battery is formed in single-piece construction with insulating layers to establish a battery module, and the insulating layers that have a fit-together structure. Therefore, even though prior-art insulating separators are not used, adjacent rectangular batteries can be reliably insulated, and shift in the relative position between batteries can be prevented.
In the power source apparatus to supply electric power of the present invention, the insulating layers 2, 42, 52, 62 can be formed to cover at least the primary surfaces 1B of each external case 11. In this patent application, the primary surfaces 1B of the external case 11 indicate the surfaces that face each other when the rectangular batteries are stacked together. Since the power source apparatus described above has the primary surfaces of the external cases covered by insulating layers, stacked rectangular batteries can be reliably insulated from one another. Further, since the primary surfaces of each rectangular battery are covered by insulating layers, even if condensation forms on the battery, that condensation can be restrained from propagating to the electrode terminals established on the upper surface of the battery.
In the power source apparatus to supply electric power of the present invention, a rectangular battery 1 can be insertion molded in the insulating layers 2, 42, 52, 62 to form a battery module 10, which is a single-piece structure that includes the rectangular battery 1 and the insulating layers 2, 42, 52, 62. In this power source apparatus, insulating layers can be simply and easily formed on rectangular battery surfaces to reliably insulate adjacent batteries.
In the power source apparatus to supply electric power of the present invention, the plurality of battery modules 10 stacked together in a battery block 3 can be sandwiched in the stacking direction by endplates 7 at each end, and the battery modules 10 can be held in the stack by fastening components 8 that connect the two endplates 7. In this power source apparatus, the battery modules in the battery block, which is held together by fastening components connected to the endplates at both ends, can be placed on the cooling plate and the battery modules can be reliably held in thermal connection with the cooling plate.
In the power source apparatus to supply electric power of the present invention, the battery modules 10 and endplates 7 can have a fit-together structure that allows them to be stacked together in fixed positions. In this power source apparatus, the battery modules and endplates can be reliably held together without shifting position.
In the power source apparatus to supply electric power of the present invention, the insulating layers 2, 42, 52, 62 of the battery modules 10 can be made thicker in center regions than in periphery regions. With the battery modules in a stacked configuration, insulating layer surfaces at the center regions of adjacent battery modules make contact and prevent strong forces from pressing against the perimeter regions of the rectangular batteries. This prevents detrimental effects such as deformation of rectangular battery perimeter regions.
In the power source apparatus to supply electric power of the present invention, thermally conducting sheet 6 that distorts with compression can be disposed between the battery block 3 and the cooling plate 4. In this power source apparatus, each rectangular battery can be stably and reliably joined to the cooling plate in a thermally coupled manner via the thermally conducting sheet. This allows each rectangular battery to be reliably cooled without developing temperature differentials between batteries.
In the power source apparatus to supply electric power of the present invention, the bottom surface of the insulating layers 2, 42, 52, 62 of each battery module 10, which is the surface opposite the cooling plate 4, can have an open region 22 that exposes the external case 11. The thermally conducting sheet 6, which is made of electrically insulating material, can be disposed in the open regions 22 to join each external case 11 with the cooling plate 4 in a thermally coupled manner via the thermally conducting sheet 6. In this power source apparatus, the thermally conducting sheet can be disposed in a fixed location without position shift with respect to the insulating layers to reliably join and thermally couple the bottom surface of each rectangular battery external case with the cooling plate. This allows the cooling plate to cool each rectangular battery in a stable manner without developing temperature differentials between batteries.
In the power source apparatus to supply electric power of the present invention, battery module 10 insulating layers 2, 42, 52, 62 on the bottom surface 1A of each external case 11 can have cover regions 23 that cover both ends of the bottom surface 1A, and the open region 22 can be established between those cover regions 23. Further, the interfaces 24 between the cover regions 23 and the open region 22 can be inclined in a manner that increases the open region 22 area in the direction from the bottom surfaces 1A of the rectangular batteries 1 towards the cooling plate 4. In this power source apparatus, thermally conducting sheet inserted in the open regions of the insulating layers is sandwiched between the cooling plate and the bottom surfaces of the rectangular batteries. Consequently, each rectangular battery spreads the thermally conducting sheet to tightly contact and thermally couple with an even wider area of the cooling plate for efficient battery cooling that reduces temperature differentials between batteries.
The power source apparatus to supply electric power of the present invention can be an apparatus that supplies power to a motor that drives a vehicle. This power source apparatus can be used in a configuration that increases output to deliver high power to a motor while reliably holding many rectangular batteries in fixed positions as battery modules. In particular, many rectangular batteries can be held in fixed positions over a long period, and position shift can be prevented between the rectangular batteries and insulating layers due to vehicle vibration. This achieves the characteristic of enabling safe operation.
The power source apparatus to supply electric power of the present invention can be an apparatus that is charged by solar cells to store solar cell generated power. This power source apparatus can be used in a configuration that increases output and allows charging by high output solar cells while reliably holding many rectangular batteries in fixed positions as battery modules. This achieves the characteristic of allowing operation over a long period with many rectangular batteries held stably in fixed positions.
The vehicle of the present invention can be equipped with any of the power source apparatus described above. 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 describes embodiments of the present invention based on the figures. However, the following embodiments are merely specific examples of a power source apparatus to supply electric power and vehicle equipped with the power source apparatus representative of the technology associated with the present invention, and the power source apparatus and vehicle of the present invention are not limited to the embodiments described below. Further, to promote understanding of the scope of the claims, components shown in the embodiments of this patent application are named and labeled. However, components cited in the claims are in no way limited to the components described in the embodiments.
Primarily, the power source apparatus to supply electric power of the present invention is carried in an electric powered vehicle such as a hybrid vehicle or electric vehicle, and is used as the driving power source that supplies power to the driving motor of the vehicle. Or, the power source apparatus is used to store solar cell power and output power at night or during daytime peak-power usage times.
The power source apparatus shown in
The rectangular batteries 1 are lithium ion rechargeable batteries. However, the rectangular batteries are not limited to lithium ion rechargeable batteries, and any batteries that can be charged, such as nickel hydride batteries, can also be used. Each rectangular battery has an electrode unit, which is a stack of positive and negative electrode plates (not illustrated), held in an external case 11 that is filled with electrolyte and sealed closed in an air-tight manner. As shown in
Although not illustrated, stacked rectangular batteries 1 have adjacent electrode terminals 13 connected in series or parallel. No potential difference develops between the external cases 11 of rectangular batteries 1 connected in parallel. However, a high output power source apparatus does not have all its rectangular batteries 1 connected in parallel, and series-connection is used to increase the output voltage. Potential difference develops between adjacent rectangular batteries 1 when they are connected in series. Accordingly, the power source apparatus has rectangular batteries 1 stacked in an electrically insulated manner with insulating layers 2 sandwiched between adjacent batteries 1. Further, the insulating layers 2 between the stacked rectangular batteries 1 thermally isolate adjacent batteries 1. Consequently, even if the temperature of a rectangular battery 1 becomes abnormally high in a thermal runaway condition, the insulating layers 2 act to prevent thermal runaway from spreading to adjacent batteries 1. Therefore, even in a battery block with insulating layers disposed between parallel-connected rectangular batteries, thermal runaway can be prevented and safety improved.
Further, lead-wires (not illustrated) are connected to the electrode terminals 13 of each rectangular battery 1. The lead-wires are connected to a circuit board (not illustrated) carrying protection circuitry that detects rectangular battery 1 voltage. Although not illustrated, the circuit board is disposed on top of the power source apparatus shown in
The battery block 3 has insulating layers 2 disposed between adjacent rectangular batteries 1. The insulating layers 2 cover at least the opposing surfaces of adjacent rectangular batteries 1, which are essentially the entire primary surfaces 1B of each external case 11. In addition to electrically insulating the external cases 11 of adjacent rectangular batteries 1, the insulating layers 2 also cut-off heat transfer between adjacent batteries 1. Accordingly, the insulating layers 2 are made by molding plastic. However, the insulating layers can also be made by forming insulating material such as rubber instead of plastic.
The insulating layers 2 are formed by insertion molding the rectangular battery 1 to form a battery module 10, which is the rectangular battery 1 and insulating layers 2 formed as a single-piece structure. A battery module 10 is formed by placing a rectangular battery 1 in the insulating layer 2 mold cavity and injection molding plastic into the mold. As shown in
Although not illustrated, the insulating layers can also be a molded elastic structure formed from flexible material such as soft plastic or rubber in a shape that conforms to the outline of a rectangular battery. This molded elastic structure can be attached to the outer surfaces of the rectangular battery. For example, the molded elastic structure can be stretched open and a rectangular battery can be inserted inside tightly attaching the insulating layers in a flexible manner to cover the surfaces of the external case. In this manner, the insulating layers and external case can form a single-unit, and the rectangular battery and insulating layers can make up a battery module that has a single-piece configuration. These insulating layers can also cover the entire rectangular battery (lateral) periphery and both ends of the bottom surface leaving the upper surface and the bottom surface excluding the end regions exposed.
The insulating layers 2 of
The insulating layers 2 are provided with thick sections 21 that cover the center regions of the battery module 10 stacking surfaces 17 and are formed thicker than insulating layers in the perimeter regions of the stacking surfaces 17. When battery modules 10 with these insulating layers 2 are stacked with their stacking surfaces 17 in tight contact, insulating layer 2 thick sections 21 at center regions of the stacking surfaces 17 make surface contact and prevent strong forces from being applied at regions around the perimeters of the rectangular batteries 1.
The battery modules 10, which are rectangular batteries 1 and insulating layers 2 formed in single-piece construction, are shaped to stack in fixed positions via insulating layers 2 that have a fit-together structure. The fit-together structure of the insulating layers 2 has mating projections 25 and cavities 26 established facing each other on opposing stacking surfaces 17 of adjacently stacked battery modules 10. In this fit-together structure, projections 25 on a stacking surface 17 insert into opposing cavities 26 to connect battery modules 10. However, the fit-together structure could also be provided with insertion holes instead of cavities to accept the projections.
Insulating layers 2 of the battery modules 10 shown in
The insulating layers 2 shown in the figures have projections 25 with circular shapes and cavities 26 with circular shaped interiors that conform to the outlines of the projections 25 and accept their insertion. The shape of the inside of the cavities 26 is approximately equal to, or slightly larger than the outside shape of the projections 25. This enables the projections 25 and cavities 26 to fit-together and connect. A fit-together structure that aligns circular projections 25 into cavities 26 allows battery modules 10 to be stacked in fixed positions with given orientation by establishing a plurality of projections 25 and cavities 26 on the stacking surfaces 17. However, the projections and cavities do not necessarily have to have circular shapes, and they could also have polygonal shapes. Specifically, the projections can have polygonal shapes, and the interiors of the cavities can have polygonal shapes that conform to the outside shapes of the projections. In a fit-together structure that aligns polygonal projections into polygonal cavities, battery modules can be stacked in fixed positions with given orientation by establishing one, or a plurality of polygonal projections and cavities in the stacking surfaces. In addition, the insulating layer fit-together structure could also be made up of projections that are projecting rails and cavities that are grooves that accept insertion of the projecting rails. This type of fit-together structure also allows battery modules to be stacked together in fixed positions with given orientation.
As shown in
The insulating layer fit-together structure can also have the configuration shown in
The insulating layer fit-together structure is not limited to configurations with projections and cavities as described above. For example, as shown in
Insulating layer alignment tabs can also be configured as shown in
Note, the insulating layer fit-together structure of the power source apparatus of the present invention is not limited to the structures described above. Accordingly, the insulating layer fit-together structure can be any configuration that fits battery modules together in a stack without position shift between adjacent battery modules.
As shown in
As shown in the enlarged inset of
The thermally conducting sheet 6 is squeezed between battery block 3 rectangular batteries 1 and the cooling plate 4 and distorts to tightly contact the bottom surfaces 1A of the rectangular batteries 1 with the surface of the cooling plate 4. The surfaces of the thermally conducting sheet 6 can also be coated with electrically insulating thermal grease (thermal gel, thermal compound, thermal paste, heat paste, heat sink paste, heat transfer compound, heat transfer paste [HTP], heat sink compound) such as a silicone oil-based compound to tightly attach the bottom surfaces 1A of the rectangular batteries 1 with the surface of the cooling plate 4 in an even more stable and reliable manner. Although not illustrated, the open regions that expose rectangular battery bottom surfaces can also be filled with thermal grease to connect the bottom surfaces of the rectangular batteries in a thermally coupled manner with the cooling plate via the thermal grease. In this configuration, thermally conducting sheet does not necessarily have to be used, and the rectangular batteries can be thermally coupled to the surface of the cooling plate by thermal grease alone.
In the power source apparatus described above, the bottom surface 1A of each rectangular battery 1 can be stably and reliably connected to the cooling plate 4 in a thermally coupled manner via thermally conducting sheet 6 and/or thermal grease. Accordingly, each rectangular battery 1 can be efficiently cooled in a manner that reduces temperature differentials between batteries 1. However, the power source apparatus of the present invention can also be implemented by connecting insulating layer covered rectangular batteries in a thermally coupled manner to the surface of the cooling plate without exposing the bottom surfaces of the batteries.
As shown in
The endplates 7 are made of hard plastic that is molded, or are made of a metal such as aluminum or aluminum alloy. The endplates 7 have the same rectangular outline as the battery modules 10 to hold the battery modules 10 over a wide area. The rectangular endplates 7 are made the same size as the battery modules 10 or are made slightly larger than the battery modules 10. In addition, the endplates 7 have a fit-together structure that interconnects with the stacking surfaces 17 of adjacent battery modules 10 to connect with the battery modules in a manner that does not shift position. This fit-together structure can be the same as the battery module 10 fit-together structure described previously. The endplates 7 shown in
The end regions of fastening components 8, which are metal bands 8A, are connected to the endplates 7. The metal bands 8A are connected to the endplates via set-screws 8B. Endplates 7, which connect with metal bands 8A by set-screws 8B, are provided with screw-holes 7a that accept set-screw 8B insertion. The screw-holes 7a are established in the outer surfaces of the endplates 7, and set-screws 8B inserted through bent regions 8a at both ends of the metal bands 8A screw into the screw-holes 7a to connect the metal bands 8A. Although the metal bands 8A of the figures attach to the endplates 7 via set-screws 8B, the metal bands can also connect to the endplates by other attachment methods. For example, end regions of the metal bands can be bent inward for endplate attachment, or the end regions of the metal bands can be crimp-attached to the endplates.
The power source apparatus of
The metal bands 8A are made from sheet-metal of a given thickness formed with a given width. The ends of the metal bands 8A connect to the endplates 7 to retain a plurality of battery modules 10 in a compressed state between the pair of endplates 7. The metal bands 8A fix the dimension between the pair of endplates 7 to hold stacked rectangular batteries 1 and insulating layers 2 between the endplates 7 in a given state of compression. If rectangular battery 1 expansion pressure stretches the metal bands 8A, battery 1 expansion cannot be prevented. Accordingly, the metal bands 8A are formed from sheet-metal strong enough to avoid stretching due to rectangular battery 1 expansion pressure, and are formed with a thickness and width that achieves sufficient strength. For example, the metal bands 8A are made of sheet-metal such as SUS304 stainless-steel sheet-metal or other steel sheet-metal. The metal bands can also be made by forming sheet-metal in a channel-shape (with a u-shaped cross-section). Since metal bands with this shape have good bending strength, they are characterized by the ability to solidly retain a stack of rectangular batteries in a given state of compression while making the metal bands narrower.
The ends of the metal bands 8A are provided with bent regions 8a, and the bent regions 8a connect to the endplates 7. The bent regions 8a are provided with through-holes for the set-screws 8B, and the metal bands 8A are attached to the endplates 7 via set-screws 8B inserted through the through-holes.
As shown in
As shown in
The cooling mechanism 5 controls the state of cooling of the cooling plate 4 via temperature sensors (not illustrated) that detect rectangular battery 1 temperature. Specifically, when rectangular battery 1 temperature exceeds a preset initiate-cooling-temperature, coolant is supplied to cool the cooling plate 4. When rectangular battery 1 temperature drops below a cease-cooling-temperature, the supply of coolant to the cooling plate 4 is stopped. This controls rectangular battery 1 temperature within a preset temperature range.
The power source apparatus described above can be used as a power source on-board a vehicle. An electric powered vehicle such as a hybrid vehicle driven by both an engine and an electric motor, a plug-in hybrid vehicle, or an electric vehicle driven by an electric motor only can be equipped with the power source apparatus and use it as an on-board power source.
Further, application of the power source apparatus of the present invention is not limited to the power source for the driving motor in a vehicle. The power source apparatus of the present invention can also be used as the power source in a power storage apparatus that stores power by charging batteries with power generated by methods such as solar power or wind power generation. Or, the power source apparatus can be used as the power source in a power storage apparatus that stores power by charging batteries with late-night (reduced-rate) power. A power source apparatus charged by late-night power is charged by surplus power generated by the power plant late at night, and outputs power during the daytime when demand is high. This allows daytime peak-power usage to be limited. The power source apparatus can also be used as a power source that is charged by both solar cell output and late-night power. This type of power source apparatus effectively uses both late-night power and power generated by solar cells, and can take weather conditions and power consumption patterns into consideration to efficiently store power.
The power storage apparatus shown in
The type of power storage apparatus described above can be used advantageously in applications such as a back-up power source that can be installed in a server computer rack, a back-up power source in a wireless base station such as mobile phone base station, the power source in a power storage system for use in the home or manufacturing facility, a streetlight power source, and a power source for traffic signals or other roadside indicators etc. It should be apparent to those with an ordinary skill in the art that while various preferred embodiments of the invention have been shown and described, it is contemplated that the invention is not limited to the particular embodiments disclosed, which are deemed to be merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention, and which are suitable for all modifications and changes falling within the spirit and scope of the invention as defined in the appended claims. The present application is based on Application No. 2011-117416 filed in Japan on May 25, 2011, the content of which is incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-117416 | May 2011 | JP | national |
