Patent Application
20150129332
The present invention is related to a battery pack and a method for manufacturing the same in which a plurality of flat secondary batteries are stacked, especially, the battery pack and the method for manufacturing the same in which a battery stacked member stacking the flat secondary batteries is fixed in the pressed state by end plates at both ends thereof.
A flat secondary battery in which an electrode assembly and an electrolyte as elements of generation of electricity are sealed in an outer case having a rectangular box shape, is developed (refer to patent literature 1).
In the flat secondary battery, the electrode assembly is swollen by charging and discharging. Concretely, the electrode assembly is swollen by charging the flat secondary battery, and is contracted by discharging the flat secondary battery. Further, active layers of the electrode assembly are swollen also by repeatedly charging and discharging.
As the power source having a high output or a high capacity in which this type of the secondary battery is used, a battery pack in which a plurality of the flat secondary batteries are stacked, is developed (refer to patent literature 2).
In this battery pack, a volume efficiency is high, and an energy density to volume is high. Concretely, by connecting the stacked flat secondary battery in series, the output voltage is increased, and by connecting the stacked flat secondary battery in parallel, the capacity is increased. In this battery pack, a plurality of the flat secondary batteries are stacked through insulating member as the battery staked member, and end plates are disposed at both ends of the battery staked member, and the end plates are coupled by binding bars, and the flat secondary batteries are fixed in the stacked state. As mentioned above, the flat secondary battery is swollen by charging and discharging, or the degradation of the battery, the deformation or swell of the battery stacked member is prevented by the end plates and the binding bars in the battery pack.
Patent Literature 1: Japanese Laid-Open Patent Publication No. 2012-109219
Patent Literature 2: Japanese Laid-Open Patent Publication No. 2011-23301
In a battery pack fixed in a staked state of alternately stacking a plurality of flat secondary batteries and an insulating material, the flat secondary batteries are compressed and fixed in a predetermined binding pressure from both sides, by binding bars being coupled to end plates at both ends of a battery stacked member. In order to fix the flat secondary batteries in a compressed state, the battery pack is assembled in the following steps.
However, when the flat secondary batteries are compressed in the predetermined binding pressure, the binding pressure is also applied to an electrode assembly which is stored in an outer case. Therefore, it happens that distances between electrode plates in a state of the battery stacked member with external pressure is shorter than distances between electrode plates in a state of the flat secondary battery of a single body without external pressure, depending on value of the binding pressure, and it is likely to influence the battery property. As binding of the binding bars and the end plates is carried out in order to made the battery stacked member within a predetermined size, the binding pressure does not necessarily become constant. Therefore, when the battery packs are manufactured, there is a problem that dispersion or differences among the battery packs in the battery property happen. Further, also in a structure to suppress or reduce dispersion or differences among the battery packs in the battery property by the binding pressure being made constant, there is a problem that dispersion or differences among sizes of the battery stacked members become bigger. When design or manufacturing allowance is big, there are problems that it is difficult to fix the battery pack, etc.
The present disclosure is developed for the purpose of providing the battery pack which reduces or suppresses an influence of the battery property, and prevents a deformation, a swell, or an expansion of the battery stacked member. One non-limiting and explanatory embodiment provides a battery pack and a method for manufacturing the battery pack, and a vehicle and a storage battery device equipped with the battery pack which in addition to preventing a deformation, a swell, or an expansion of the battery stacked member, reduces or suppresses dispersion or differences of the battery property among the battery packs, or dispersion or differences of the sizes among the battery stacked member.
A battery pack of the present disclosure comprises a battery staked member stacking a plurality of flat secondary batteries, end plates being disposed at both ends of the battery staked member and binding bars being coupled to the end plates in a pressed state that the flat secondary batteries of the battery staked member are compressed and fixed in a predetermined binding pressure. The flat secondary batteries constituting the battery staked member comprise an electrode assembly of a spiral form in which a positive electrode plate and a negative electrode plate interposing a separator therebetween are wound, and an outer case airtightly storing the spiral electrode assembly and an electrolyte. The spiral electrode assemblies of the flat secondary batteries are pressed and made into a flat shape by a higher pressing pressure than the predetermined binding pressure in which the flat secondary batteries are bound by the binding bars.
Accordingly, in addition to preventing a deformation, a swell, or an expansion of the battery stacked member, the battery pack reduces or suppresses dispersion or differences of the battery property among the battery packs, or dispersion or differences of the sizes among the battery stacked member. It is a reason why the spiral electrode assemblies pressed and made into a flat shape by a higher pressing pressure than the predetermined binding pressure in which the flat secondary batteries are bound by the binding bars, are stored into the outer case. As the electrode assembly of the flat secondary battery, the electrode assemblies pressed and made by the high pressing pressure are used, and the binding pressure of the flat secondary battery fixed by the end plates in a stacked state, is set at low value. The binding pressure of the end plated coupled to the binding bars is applied to the outer case of the flat secondary battery, but this binding pressure is lower than the press pressure of the electrode assembly, and then the electrode assembly is not deformed by the binding pressure. Therefore, as the electrode assembly of the flat shape pressed by the press pressure which is higher than the binding pressure, is inserted into the outer case, when the battery stacked member is bound by the end plates and the binding bars, the deformation of the electrode assembly by the binding pressure can be prevented. Further, the decrease of the battery property can be reduced or suppressed in a state of repeatedly charging and discharging, because the pressed electrode assembly stored into the outer case, is pressed in the flat shape by the press pressure higher than the binding pressure. Especially, as the electrode assembly in which the positive electrode plate and the negative electrode are wound in the spiral form interposing the separator therebetween, is pressed and made in the flat shape by the strong press pressure, the positive electrode plate and the negative electrode plate become in a tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is reduced or suppressed. Further, as the electrode assembly is pressed and made in the flat shape by the strong press pressure, the positive electrode plate, the negative electrode plate, and the separator, are made such that the flat plane portions are coupled to the curved portions, and the positive electrode plate and the negative electrode plate are fixed in the tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is effectively prevented. As the swell of the electrode assembly by charging and discharging is reduced or suppressed in the above battery pack, the outer case is not damaged even though the flat secondary batteries are strongly bound. Therefore, the degradation of the battery property is effectively prevented in a long time period, and the life can be made longer.
In the battery pack in the present disclosure, the flat secondary batteries are non-aqueous electrolyte secondary batteries.
Accordingly, as the flat secondary batteries are non-aqueous electrolyte secondary batteries, the decrease of the battery property can be reduced or suppressed even in a state of repeatedly charging and discharging. Especially, as the electrode assembly in which the positive electrode plate and the negative electrode are wound in the spiral form interposing the separator therebetween, is pressed and made in the flat shape by the strong press pressure, the positive electrode plate and the negative electrode plate become in a tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is reduced or suppressed.
In the battery pack in the present disclosure, the non-aqueous electrolyte secondary batteries are lithium ion secondary batteries.
Accordingly, as the non-aqueous electrolyte secondary batteries are lithium ion secondary batteries, while a charging capacity with respect to volume and weight is increased, the swell of the electrode assembly is effectively reduced or suppressed.
In the battery pack in the present disclosure, the pressing pressure of the spiral electrode assemblies is equal to or more than twice the binding pressure of the flat secondary batteries.
Accordingly, as the pressing pressure of the spiral electrode assemblies is equal to or more than twice the binding pressure of the flat secondary batteries, while the electrode assembly is surely pressed into the flat shape, and the battery staked member is bound without the damage of the outer case, the degradation of the battery property by the swell of the electrode assembly is effectively prevented in a state that the electrode assembly is stored into the outer case.
In the battery pack in the present disclosure, the separator of the electrode assembly is a thermoplasticity resin film of porous membrane.
Accordingly, as the electrode assembly in the spiral form is pressed into the flat shape by the strong press pressure, the positive electrode plate and the negative electrode plate become in a tightly contacted or consolidated state of high density. Therefore, the decrease of the battery property by the swell of the electrode assembly can be reduced or suppressed.
In the battery pack in the present disclosure, the outer case comprises an outer can having an opening portion and a sealing plate, and the opening portion of the outer can is airtightly sealed and closed by the sealing plate by laser welding, and the pressed electrode assembly is stored in the outer can in a posture that an winding axis of the spiral form is disposed in parallel with the sealing plate.
Accordingly, the damage of the outer case is surely prevented, since the electrode assembly in the spiral form is swollen or expanded at the center between the sealing plate and the bottom portion, and the connecting portion between the outer can and the sealing plate is not pressed from inside.
In the battery pack in the present disclosure, the end plate is a rectangular shape as a whole shape, and the end plates are coupled to the binding bars at the four corners thereof.
Accordingly, by the end plates and the binding bars, the whole flat secondary battery is fixed in a pressed state by the uniform binding pressure, and demerits by the swell or expansion of the flat secondary battery can be reduced or suppressed.
In the battery pack in the present disclosure, the binding bar is a metal board having a L-shape in a lateral sectional view.
Accordingly, as the bending strength of the binding bar becomes strong, the end plates are disposed at the fixed position, and the flat secondary batteries can be stably pressed and fixed in the stacking direction by the predetermined binding pressure.
A method for manufacturing a battery pack of the preset disclosure comprises a winding step of winding into a spiral electrode assembly a positive electrode plate and a negative electrode plate interposing a separator therebetween, a pressed shaping step of pressing the spiral electrode assembly obtained in the winding step into a flat pressed electrode assembly, a sealing step of airtightly sealing an outer case in a state that the flat pressed spiral electrode assembly obtained in the pressed shaping step is inserted in the outer case and an electrolyte is filled into the outer case, as flat secondary batteries, a stacking step of stacking a plurality of the flat secondary batteries obtained in the sealing step as a battery staked member, and a binding step of binding and fixing in a pressed state of the flat secondary batteries of the battery staked member in a predetermined pressure by disposing end plates at both ends of the battery staked member obtained in the stacking step and coupling binding bars to a pair of the end plates. In the method for manufacturing the battery pack, the spiral electrode assemblies of the pressed shaping step are pressed and made by a stronger pressing pressure than the binding pressure by which the flat secondary batteries are compressed in the binding step.
Accordingly, the spiral electrode assemblies of the pressed shaping step are pressed and made by a stronger pressing pressure than the binding pressure by which the flat secondary batteries are compressed in the binding step. The binding pressure of the end plated coupled to the binding bars in the binding step is applied to the outer case of the flat secondary battery, but this binding pressure is lower than the press pressure of the electrode assembly in the pressed shaping step, and then the electrode assembly is not deformed by the binding pressure. Therefore, in the above method for manufacturing, as the electrode assembly of the flat shape pressed by the press pressure which is higher than the binding pressure, is inserted into the outer case, when the battery stacked member is bound by the end plates and the binding bars, the deformation of the electrode assembly by the binding pressure can be prevented. Further, the decrease of the battery property can be reduced or suppressed in a state of repeatedly charging and discharging, because the pressed electrode assembly stored into the outer case, is pressed in the flat shape by the press pressure higher than the binding pressure. Especially, as the electrode assembly in which the positive electrode plate and the negative electrode are wound in the spiral form interposing the separator therebetween, is pressed and made in the flat shape by the strong press pressure, the positive electrode plate and the negative electrode plate become in a tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is reduced or suppressed. Further, as the electrode assembly is pressed and made in the flat shape by the strong press pressure in the pressed shaping step, the positive electrode plate, the negative electrode plate, and the separator, are made such that the flat plane portions are coupled to the curved portions, and the positive electrode plate and the negative electrode plate are fixed in the tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is effectively prevented. As the swell of the electrode assembly by charging and discharging in the battery pack obtained in the above method for manufacturing is reduced or suppressed, the outer case is not damaged even though the flat secondary batteries are strongly bound. Therefore, the degradation of the battery property is effectively prevented in a long time period, and the life can be made longer.
In the method for manufacturing in the present disclosure, the flat secondary batteries are non-aqueous electrolyte secondary batteries.
Accordingly, as the flat secondary batteries are non-aqueous electrolyte secondary batteries, the decrease of the battery property can be reduced or suppressed even in a state of repeatedly charging and discharging. Especially, as the electrode assembly in which the positive electrode plate and the negative electrode are wound in the spiral form interposing the separator therebetween, is pressed and made in the flat shape by the strong press pressure, the positive electrode plate and the negative electrode plate become in a tightly contacted or consolidated state of high density, and then the swell of the electrode assembly is reduced or suppressed.
In the method for manufacturing in the present disclosure, the non-aqueous electrolyte secondary batteries are lithium ion secondary batteries.
Accordingly, as the non-aqueous electrolyte secondary batteries are lithium ion secondary batteries, while a charging capacity with respect to volume and weight is increased, the swell of the electrode assembly is effectively reduced or suppressed.
In the method for manufacturing in the present disclosure, the pressing pressure of the spiral electrode assembly 11U in the pressed shaping step is equal to or more than 1 M Pa, and equal to or less than 20 M Pa, and this pressing pressure is equal to or more than twice the binding pressure of the flat secondary batteries 1 in the binding step.
Accordingly, as the pressing pressure of the spiral electrode assemblies in the pressed shaping step is equal to or more than twice the binding pressure of the flat secondary batteries in the binding step, while the electrode assembly is surely pressed into the flat shape in the pressed shaping step, and the battery staked member is bound without the damage of the outer case in the binding step, the degradation of the battery property by the swell of the electrode assembly is effectively prevented in a state that the electrode assembly is stored into the outer case.
A vehicle in the present disclosure, comprises any one of the above battery packs, an electric motor being energized by electric power that is supplied from the battery pack, a vehicle body having the battery pack and the electric motor, and a wheel being driven by the electric motor, and driving the vehicle body.
A storage battery device in the present disclosure, comprises any one of the above battery packs, and a power supply controller controlling charging and discharging of the battery pack. The battery pack is charged with an external power by the power supply controller, and charging of the battery pack is controlled by the power supply controller.
Hereinafter, the embodiment of the present invention will be described referring to drawings. However, the following embodiments illustrate a battery pack and a method for manufacturing the battery pack, and a vehicle and a storage battery device equipped with the battery pack which are aimed at embodying the technological concept of the present invention, and the present invention is not limited to the battery pack and the method for manufacturing the battery pack, and the vehicle and the storage battery device equipped with the battery pack described below. However, the members illustrated in Claims are not limited to the members in the embodiments.
A battery pack 100 of
The end plates 4 are disposed at both ends of the battery staked member 9. As shown in the schematic sectional view of
The binding bars 5 are metal boards each having a L-shape in a lateral sectional view, and at both ends, the binding bars 5 have end edge plates 5A. The end edge plates 5A are coupled to L-shaped end surfaces of the binding bars 5, and contact the outer side surfaces of the end plates 4. The end edge plates 5A are disposed at the outer side surfaces of the end plates 4, and the binding bars 5 are coupled to the end plates 4. The end edge plates 5A of the binding bars 5 are coupled to the end plates 4, and by the end plates 4, the flat secondary batteries 1 are fixed in the compressed state. Further, the binding bars 4 are fixed to the outer surface of the end plates 4 by screw or the like. In the above battery pack 100, both ends of the binding bars 5 are coupled to a pair of the end plates 4, and the battery staked member 9 is sandwiched between the end plates 4, and each of the flat secondary batteries 1 are compressed by the predetermined binding pressure (P2), and are fixed in the pressed state in the stacked direction. The binding pressure (P2) of the flat secondary battery 1 is a pressing force per unit area which is put on both surfaces of the flat secondary battery 1. Therefore, the binding pressure (P2) is calculated by [the pressing force that the end plates 4 press the battery staked member 9 in the stacked direction]/[area of a flat portion of the flat secondary battery 1]. The binding pressure (P2) is set at preferably equal to or more than 10 kPa, equal to or less than 1 MPa. When the binding pressure (P2) is too weak, the swell of the flat secondary battery 1 is not effectively suppressed or reduced. Conversely, when the binding pressure (P2) is too strong, problem that the outer case 12 of the flat secondary battery 1 is damaged, occurs. Therefore, the binding pressure (P2) is set at an optimum value in the above range, considering type or size of the flat secondary battery, further material, shape, wall thickness, size, swell property of the electrode assembly, or the like.
The above flat secondary battery 1 is manufactured in the following steps.
The positive electrode plate 11A and the negative electrode plate 11B interposing separators 11C therebetween are wound into the spiral form, and then the spiral electrode assembly 11U shown in
As shown in
The electrode assembly 11 of the flat shape obtained in the pressed shaping step is inserted into the outer can 12a of the flat shape as shown in
In the flat secondary battery 1 manufactured in the above steps, as shown in FIG. 4, the mixture of an active material 32, a conductive agent, and a binder is formed on the surfaces of a core 31, and the positive plate 11A and the negative plate 11B are made. The positive plate 11A and the negative plate 11B are stacked interposing separators 11C therebetween, and this is wound as shown in
The non-aqueous electrolyte battery is suitable for the flat secondary battery 1. A lithium ion secondary battery is suitable for the non-aqueous electrolyte battery. The battery pack in which the flat secondary battery 1 is the lithium ion secondary battery of the non-aqueous electrolyte battery can increase a charging capacity with respect to volume and weight of the battery staked member 9. In the present invention, the flat secondary battery is not specified by the lithium ion battery of the non-aqueous electrolyte battery, and all rechargeable batteries, for example, such as, the non-aqueous electrolyte battery other than the lithium ion battery, a nickel hydride battery, a nickel cadmium battery, or the like can be applied to the present invention.
A positive or negative electrode terminal 15 is insulated from the sealing plate 12b, and is fixed at both end portions of the sealing plate 12a. The positive or negative electrode terminal 15 is connected to the positive or negative core 31 of the electrode assembly 11 which is disposed inside the outer can 12a through current collector 14. Further, the sealing plate 12b has a safety valve 34 which opens its valve when the internal pressure is increased up to a predetermined pressure. As the outer shape of the sealing plate 12b is approximately the same as the inner shape of the opening portion of the outer can 12a, the sealing plate 12b is inserted into the opening portion of the outer can 12a, and a laser beam is irradiated to a boundary between the sealing plate 12b and the outer can 12a, and the opening portion of the outer can 12a is airtightly sealed.
In the electrode assembly 11 of
As shown in
The positive electrode plate 11A is preferably prepared in the following. Li2CO3 and (Ni0.35Co0.35Mn0.3)3O4 were mixed such that Li and (Ni0.35Co0.35Mn0.3) were in the ratio of 1:1 by mol. Thereafter, this mixture was calcined at 900° C. for 20 hours in the atmosphere of the air, and a lithium transition-metal composite oxide expressed by LiNi0.35Co0.35Mn0.3O2 was obtained as the positive electrode active material 32A. The above positive electrode active material 32A, a flaky graphite and a carbon black as a conductive agent, and a powder of polyvinylidene fluoride (PVdF) as a binder were mixed in the ratio of 88:7:2:3(=lithium transition-metal composite oxide:flaky graphite:carbon black:PVdF) by mass. The resultant mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to make a positive electrode mixture slurry. This positive electrode mixture slurry was coated on one surface of a 15 μm(=micrometer) thick positive electrode core 31A made of aluminum alloy foil, and by drying and eliminating NMP used as a solvent at the time of making the slurry, a positive electrode mixture layer containing the positive electrode active material was formed. In the same way, the positive electrode mixture layer containing the positive electrode active material was formed on the other surface of the aluminum alloy foil. After that, it was pressed with a roll press, and by cutting it into the predetermined size the positive electrode plate 11A was made.
As the negative electrode active material 32B of the lithium ion secondary battery, carbon material that can reversibly adsorb and desorb lithium ions can be used. As the carbon material that can reversibly adsorb and desorb lithium ions, graphite, non-graphitized carbon, easily graphitizable carbon, glassy carbon, coke, carbon black or the like can be used.
The negative electrode plate 11B is preferably prepared in the following.
The artificial graphite as the negative electrode active material 32B, carboxymethylcellulose (CMC) as a thickener, and styrene-butadiene rubber (SBR) as a binder were mixed in the ratio of 98:1:1 by mass, and the mixture was dispersed in water to make a negative electrode mixture slurry. This negative electrode mixture slurry was coated on one surface of a 10 μm(=micrometer) thick negative electrode core 31B made of copper foil, and by drying and eliminating water used as a solvent at the time of making the slurry, a negative electrode mixture layer containing the negative electrode active material was formed. In the same way, the negative electrode mixture layer containing the negative electrode active material was formed on the other surface of the copper foil. After that, it was pressed with a roll press.
As the separator 110, a thermoplasticity resin film of porous membrane can be used. Polyolefin material of porous membrane, for example, polypropylene (PP), polyethylene (PE), or the like is suitable for the separator 11. Further, three layer structure of polypropylene (PP) and polyethylene (PE) (PP/PE/PP, or PE/PP/PE) can be used as the separator 110.
As non-aqueous solvent of non-aqueous electrolyte, kinds of carbonate, lactone, ether, ketone, ester or the like which are commonly used in a non-aqueous electrolyte secondary battery can be used, and equal to or more than two kinds of those non-aqueous solvent can be used in combination. Among these, kinds of carbonate, lactone, ether, ketone, ester or the like is preferable, and a kind of carbonate is more preferable.
For example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, or the like, and chain carbonates such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, or the like can be used. Especially It is desirable that cyclic carbonates and chain carbonates are mixed. Further, unsaturated cyclic ester of carbonic acid of vinylene carbonate (VC) or the like can be added to the non-aqueous electrolyte.
Lithium salts commonly used as the electrolyte salt in a non-aqueous electrolyte secondary battery can be used as electrolyte salts in the non-aqueous solvent. For example, LiPF6, LiBF4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiN(CF3SO2) (C4F9SO2), LiC(CF3SO2)3, LiC(C2F5SO2),3, LiAsF6, LiClO4, Li2B10Cl10, Li2B12Cl12 , LiB(C2O4)2,, LiB(O2O4) F2,, LiP(C2O4)3, LiP(C2O4)2F2,, LiP(C2O4)F4, or the like and mixtures of them can be used. Among them, especially LiPF6 is desirable. The amount of electrolyte salt dissolved in the non-aqueous solvent is preferably 0.5 to 2.0 mol/L.
The electrode assembly 11 of
As mentioned above, the electrode assembly 11 of the flat shape by pressed shaping has the exposed core areas 11Y at the opposite side portions, and an active material coating area 11X therebetween. In the exposed core areas 11Y at the opposite side portions in the electrode assembly, at one side, the core 31 of the positive electrode plate 11A is exposed, and at the other side, the core 31 of the negative electrode plate 11B is exposed. The exposed core portions 31y of the positive electrode plate 11A is stacked each other without the separator, and is connected to the current collector 14 of the positive electrode plate 11A. The exposed core portions 31y of the negative electrode plate 11B is stacked each other without the separator, and is connected to the current collector 14 of the negative electrode plate 11B. The current collector 14 of the positive electrode plate 11A and the current collector 14 of the negative electrode plate 11B are each connected by welding, etc., to the electrode terminals 15 of the positive electrode plate 11A or the negative electrode plate 11B which is fixed to the sealing plate 12b.
As mentioned above, the electrode assembly 11 of the flat shape by pressed shaping is stored in the outer can 12a in a posture that an winding axis m of the spiral form is disposed in parallel with the sealing plate 12b. The exposed core areas 11Y at the opposite side portions are disposed at both sides of the outer can 12a, namely at both sides of the wide flat surface 12A of the outer can 12a of the flat shape. The electrode assembly 11 of the flat shape by pressed shaping is inserted in the outer can 12a, and the sealing plate 12a is disposed at the opening portion of the outer can 12a. The sealing plate 12b is coupled to the electrode assembly 11 through the current collectors 14. In this state, as the electrode assembly 11 is disposed in spaced relationship with the inner surface of the sealing plate 12b, a predetermined space is provided between the electrode assembly 11 and the sealing plate 12b. The sealing plate 12b which is disposed at the opening portion of the outer can 12a is welded by laser, etc., to the opening portion of the outer can 12a. After that, the electrolyte is injected through the injection hole 33 of the sealing plate 12b into the outer can 12a, and the injection hole 33 is airtightly closed.
In the above flat secondary battery, both sides and upper and lower portions of the wide flat surface 12A of the outer can 12a as an active material non-contact area 12Y do not contact the active material coating area 11X. An area except both sides and upper and lower portions of the wide flat surface 12A as an active material contact area 12X contacts the active material coating area 11X. Both sides of the wide flat surface 12A of the outer can 12a face the exposed core area 11Y, and become the active material non-contact area 12Y which does not contact the active material coating area 11X. In the upper portion of the wide flat surface 12A, there is no electrode assembly 11 at its inner surface, or the upper portion of the wide flat surface 12A does not contact the active material coating area 11X because there is a curved portion of the spiral form in the electrode assembly 11. The lower portion of the wide flat surface 12A does not contact the active material coating area 11X because there is a curved portion of the spiral form in the electrode assembly 11. The upper and lower portions of the wide flat surface 12A become the active material non-contact area 12Y.
The insulating members 2 which are sandwiched and fixed between the flat secondary battery 1, are made by molding out of insulating plastic. The insulating members 2 shown in a plan view of
The insulating member 2 of
In the flat secondary battery 1 of
As shown in the enlarged sectional view of the
Further, the insulating members 2 shown in
The above battery pack is assembled in the following steps.
In this state, in the insulating members 2, the active material pressing portion 2X presses the active material contact area 12X more strongly than the active material non-contact area 12Y. Namely, the active material contact area 12X of the outer can is pressed by the predetermined pressure without the active material non-contact area 12Y strongly pressed.
When in the battery pack assembled in the above state, by using, the active material 32 of the electrode assembly 11 is swollen and the active material coating area 11X is swollen, the active material contact area 12X of the outer can 12a which the active material coating area 11X contacts, is pressed or pushed by the active material pressing portion 2X of the insulating member 2, and the swell of the active material coating area 11X can be prevented. Especially, as the active material contact area 12X of the outer can 12a is pressed or pushed more strongly than the active material non-contact area 12Y, while the swell of the active material coating area 11X is effectively prevented, without the upper and lower portions or both side portions apt to be damaged of the outer can 12a damaged, the swell of the active material coating area 11X of the electrode assembly 11 can be surely prevent.
The aforementioned battery packs can be used as a power supply for vehicles. The battery pack can be installed on electric vehicles such as hybrid cars that are driven by both an internal-combustion engine and an electric motor, and electric vehicles that are driven only by an electric motor. The battery pack can be used as a battery pack for these types of vehicles.
The battery pack can be used not only as power supply of mobile unit but also as stationary power storage. For example, examples of stationary power storage devices can be provided by an electric power system for home use or plant use that is charged with sunlight or with midnight electric power and is discharged when necessary, a power supply for street lights that is charged with sunlight during the daytime and is discharged during the nighttime, or a backup power supply for signal lights that drives signal lights in the event of a power failure.
The load LD driven by the battery pack 100 is connected to the battery pack 100 through the discharging switch DS. In the discharging mode of the battery pack 100, the power supply controller 84 turns the discharging switch DS ON so that the battery pack 100 is connected to the load LO. Thus, the load LD is driven with electric power from the battery pack 100. Switching elements such as FET can be used as the discharging switch DS. The discharging switch DS is turned ON/OFF by the power supply controller 84 of the battery pack 100. The power supply controller 84 includes a communication interface for communicating with an external device. In the exemplary battery pack shown in
Each of the battery packs 81 includes signal terminals and power supply terminals. The signal terminals include a pack input/output terminal DI, a pack abnormality output terminal DA, and a pack connection terminal DO. The pack input/output terminal DI serves as a terminal for providing/receiving signals to/from other battery packs and the power supply controller 84. The pack connection terminal DO serves as a terminal for providing/receiving signals to/from other battery packs as slave packs. The pack abnormality output terminal DA serves as a terminal for providing an abnormality signal of the battery pack to the outside. Also, the power supply terminal is a terminal for connecting one of the battery packs 81 to another battery pack in series or in parallel. In addition, the battery units 82 are connected to an output line OL through parallel connection switches 85, and are connected in parallel to each other.
A battery pack according to the present invention can be suitably used as battery packs 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. Also, a battery pack according to the present invention can be suitably used as backup power supply devices that can be installed on a rack of a computer server, backup power supply devices for wireless communication base stations, electric power storages for home use or plant use, electric power storage devices such as electric power storages for street lights connected to solar cells, backup power supplies for signal lights, and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-176713 | Aug 2012 | JP | national |
The present application is a national stage application of international application PCT/JP2013/004632 filed on Jul. 31, 2013, and claims the benefit of foreign priority of Japanese patent application 2012-176713 filed on Aug. 9, 2012, the contents both of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/004632 | 7/31/2013 | WO | 00 |
