JP5266634B2 - Power supply apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device capable of suppressing dispersion of current density in a bipolar battery; and its control method. <P>SOLUTION: This power supply device 100 includes: at least one bipolar battery 10 where a current flows in a stacking direction of bipolar electrodes; and a pressing part 110 capable of adjusting pressing force for pressing the bipolar battery in the stacking direction according to an environmental situation acting on the bipolar battery. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a power supply device including a bipolar battery and a control method thereof.

  In recent years, reduction of carbon dioxide emissions has been strongly desired for environmental protection. In the automobile industry, there are high expectations for reducing carbon dioxide emissions by introducing electric vehicles (EVs) and hybrid electric vehicles (HEVs), and we are eager to develop secondary batteries for motor drives that hold the key to their practical application. Has been done. As a secondary battery, attention is focused on a stacked bipolar battery that can achieve high energy density and high output density (see Patent Document 1).

A bipolar battery includes battery elements in which bipolar electrodes and electrolyte layers are alternately stacked and connected in series. In the bipolar electrode, a positive electrode is formed by providing a positive electrode active material layer on one surface of a current collector, and a negative electrode is formed by providing a negative electrode active material layer on the other surface. In a bipolar battery, current flows in the direction in which the bipolar electrodes are stacked in the battery element (hereinafter referred to as “stacking direction”), so the current path is short, the current loss is small, and the current collector is made ultrathin. You can also.
JP 2001-236946 A (paragraphs 0019, 0021)

  Variations in the environmental conditions acting on the bipolar battery, such as vibrations acting on the bipolar battery, temperature inside the bipolar battery, or temperature outside the bipolar battery, cause variations in current density in the bipolar battery. Due to the variation in the current density, the deterioration of the bipolar battery is promoted, and as a result, the durability may be reduced.

  The present invention has been made to solve the above-described problems associated with the prior art, and an object of the present invention is to provide a power supply apparatus and a control method thereof that can suppress variations in current density in a bipolar battery.

The power supply device of the present invention that achieves the above object includes at least one bipolar battery in which a current flows in the lamination direction of the bipolar electrodes,
A pressure applied as a reference for pressurizing the bipolar battery in the stacking direction is set, and a pressure adjusted with respect to the pressure applied as the reference is set in accordance with an environmental condition acting on the bipolar battery. A pressurizing part for energizing the battery ;
A case for accommodating the bipolar battery . The said pressurization part has the fluid which exists between the said bipolar battery and the said case.

Further, the control method of the power supply device of the present invention that achieves the above object includes a reference for pressing in the stacking direction when pressing at least one bipolar battery in which current flows in the stacking direction of the bipolar electrode in the stacking direction. In accordance with the environmental conditions acting on the bipolar battery, a pressure adjusted to the reference pressure is applied to the bipolar battery. The applied pressure is adjusted by the pressure of the fluid interposed between the bipolar battery and the case housing the bipolar battery.

According to the present invention, the reference pressing force for pressurizing the bipolar battery in the stacking direction is set , and the pressing force adjusted with respect to the reference pressing force is set according to the environmental conditions acting on the bipolar battery. By energizing the battery, variation in current density in the bipolar battery can be suppressed, and deterioration of the bipolar battery due to variation in current density can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings. For easy understanding, each component is exaggerated in the drawings.

  1 is a cross-sectional view showing a power supply device 100 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a bipolar battery 10, FIG. 3A is a cross-sectional view showing a bipolar electrode 20, and FIG. B) is a cross-sectional view for explaining the single cell layer 32. 4 is a cross-sectional view for explaining the temperature adjustment unit 140 of the power supply device 100, FIG. 5 is a cross-sectional view for explaining the fluid circulation unit 150 of the power supply device 100, and FIG. 6 is a conductive material having elasticity. FIG. 7 is a cross-sectional view for explaining the member 162, and FIG. 7 is a cross-sectional view for explaining the floating member 160.

  Referring to FIG. 1, the power supply apparatus 100 is roughly described in accordance with at least one bipolar battery 10 in which a current flows in the stacking direction of the bipolar electrode 20 and an environmental condition acting on the bipolar battery 10. And a pressurizing unit 110 capable of adjusting the pressurizing force for pressurizing the substrate in the stacking direction.

  Although the environmental situation which acts on the bipolar battery 10 differs depending on the place and equipment where the power supply apparatus 100 is installed, an automobile equipped with an internal combustion engine will be described as an example. When the internal combustion engine is started, a relatively large vibration is generated, and the vibration varies depending on the road surface condition and the traveling speed. Further, the temperature varies depending on the region where the automobile is used, and the heat generation temperature of the bipolar battery 10 itself also varies. Therefore, the environmental conditions include vibrations acting on the bipolar battery 10, the temperature inside the bipolar battery 10, the temperature outside the bipolar battery 10, and the like. The vibration acting on the bipolar battery 10 can be simply measured by providing a vibrometer. However, when the internal combustion engine is started, a starter is activated or not, and when traveling, a sensor or a vehicle speed sensor is used to detect a road surface condition. The degree of vibration can also be determined based on the output from. The temperature inside the bipolar battery 10 is measured by a temperature sensor. The temperature outside the bipolar battery 10 is measured by various temperature sensors such as an outside air temperature sensor provided in the air conditioner for automobiles. In the case where the power supply apparatus 100 is mounted on an automobile, the “environmental situation acting on the bipolar battery” and the “driving situation of the automobile” can be regarded as the same.

  The pressurizing unit 110 adjusts the pressurizing force that pressurizes the bipolar battery 10 in the stacking direction according to the environmental conditions acting on the bipolar battery 10. When the applied pressure is increased, the contact state between the components of the bipolar battery 10 becomes “dense”, and the battery resistance and the contact resistance are reduced. On the contrary, if the applied pressure is reduced, the contact state becomes “rough”, and the battery resistance and the contact resistance increase. Thereby, the electrical resistance of the current flowing in the stacking direction of the bipolar battery 10 can be controlled. Variation in current density can be suppressed, and deterioration of bipolar battery 10 due to variation in current density is reduced. As a result, the durability of the bipolar battery 10 and thus the power supply device 100 is improved.

  The power supply apparatus 100 further includes a case 120 that houses the bipolar battery 10. The pressurizing unit 110 has a fluid 130 existing between the bipolar battery 10 and the case 120. The fluid 130 may be a gas or a liquid. The case 120 is provided with a seal member (not shown) for the fluid 130.

  A structure in which a fluid 130 is interposed between the bipolar battery 10 and the case 120 so that the bipolar battery 10 can freely move with respect to the case 120 to some extent (space where the fluid exists) in any of the front, rear, left, and right directions. It has become. The layer of fluid 130 pressurizes the surface of bipolar battery 10 evenly according to the Pascal principle. Although it is conceivable to hold the battery with an elastic body such as a spring, the elastic body can absorb vibration, but does not have a function to pressurize the battery surface evenly. By using the fluid 130, it is possible to combine the functions of vibration absorption and uniform pressurization. The fluid 130 need not cover the entire surface of the battery, and one surface of the bipolar battery 10 may be in contact with the case 120.

  According to such a configuration, vibration from the outside is not directly transmitted to the bipolar battery 10, and therefore battery deterioration due to vibration can be prevented. In addition, the uniform pressurization makes the contact pressure (= contact resistance) between the electrode and the current extraction portion uniform, and the current extraction within the electrode surface becomes uniform.

  In the figure, reference numeral 101 denotes a current extraction mechanism arranged inside the case 120, and 102 denotes a current extraction mechanism arranged outside the case 120, each having a terminal plate shape.

  The pressurizing unit 110 includes a pressure adjusting unit 111 that adjusts the pressure of the fluid 130. The pressure adjustment unit 111 is configured by a pump or the like, and communicates with the storage space in the case 120 via the pipe 112. By controlling the pressure, it is possible to prevent the distance between the electrodes from increasing and to prevent the increase in resistance. The pressure adjustment unit 111 may be outside the case 120 and connected by a pipe 112 or the like as in the illustrated example.

  In the present embodiment, the fluid 130 also functions as a refrigerant that cools the bipolar battery 10. For this reason, the power supply apparatus 100 further includes a temperature adjustment unit 140 that adjusts the temperature of the fluid 130 (see FIG. 4). The temperature adjustment unit 140 includes a heat radiating plate 141 and a cooling fan. In some cases, the bipolar battery 10 is heated in order to enhance the startup performance when the power supply apparatus 100 is operated when the temperature or temperature of the bipolar battery 10 itself is low. For this reason, it is also preferable to provide a heater for heating the refrigerant in the temperature adjustment unit 140. By controlling the temperature of the fluid 130, the battery temperature can be indirectly controlled. The temperature adjustment unit 140 may be outside the case 120 and connected by a pipe or the like, as in the illustrated example. By causing the fluid 130 to function as a temperature control medium, the battery surface temperature can be made uniform by the convection / diffusion function, and variations in internal resistance can be reduced. As a result, the life of the bipolar battery 10 can be extended.

  A fluid circulation unit 150 that circulates the fluid 130 between the inside of the case 120 and the outside of the case 120 may be further provided (see FIG. 5). This is because the effect of cooling the bipolar battery 10 is high, and the function as a refrigerant can be sufficiently exhibited. The fluid circulation unit 150 includes a circulation pump 151, a pipe 152, and the like. In the middle of the circulation system, a heat radiating plate 141 is disposed as the temperature adjusting unit 140. By circulating the fluid 130, the spatial variation and temporal variation of the temperature control can be reduced.

  The fluid 130 is preferably an incompressible and hydrophobic fluid. By using an incompressible fluid, pressure control and temperature control become simpler. Moreover, the bipolar battery 10 can be protected from moisture by using a hydrophobic fluid. By preventing moisture from entering from the outside, deterioration of the bipolar battery 10 can be prevented.

  It is necessary for the fluid 130 to exist between at least one of both end faces of the bipolar battery 10 in the stacking direction and the case 120. This is to pressurize the bipolar battery 10 in the stacking direction.

  However, you may provide the floating member 160 which prevents each of the both end surfaces of the lamination direction of the bipolar battery 10 from contacting the inner surface of the case 120 (refer FIG. 7). The floating member 160 is made of an elastic body such as a spring. In the illustrated example, the vertically lower surface of the bipolar battery 10 and the inner surface of the case 120 are connected by a floating member 160. The floating member 160 prevents the bipolar battery 10 from contacting the lower surface of the case 120 due to gravity.

  Between the bipolar battery 10 and the case 120, a conductive member 162 that extracts current and has elasticity is disposed (see FIG. 6). The conductive member 162 having elasticity is formed of a flexible cable, and can extract current from the case 120 while attenuating propagation of vibration from the case 120 to the bipolar battery 10.

  Referring again to FIG. 1, the power supply device 100 includes a detection unit 173 that detects an environmental condition that acts on the bipolar battery 10, a controller 170 (corresponding to a control unit) that controls the operation of the pressurization unit 110, It has further. The detection unit 173 is a vibration meter 171 or a temperature sensor 172. When the power supply device 100 is mounted on a vehicle, various instruments and sensors for detecting the driving state of the vehicle can be used. it can. The controller 170 is mainly composed of a CPU and a memory, and controls the applied pressure based on the environmental situation detected by the detection unit 173. Thereby, in the bipolar battery 10, it becomes possible to control the electrical resistance of the current flowing in the stacking direction.

  In controlling the power supply apparatus 100, the controller 170 adjusts the pressure according to the environmental conditions acting on the bipolar battery 10 when the bipolar battery 10 is pressurized in the stacking direction. The adjustment of the applied pressure is made by the pressure of the fluid 130 interposed between the bipolar battery 10 and the case 120.

  By making the pressure applied to the bipolar battery 10 by the pressurizing unit 110 larger than the reference pressure, the electric resistance of the current flowing in the stacking direction becomes the current resistance flowing in the stacking direction at the reference pressure. It becomes smaller than electric resistance. On the contrary, by making the pressure applied to the bipolar battery 10 by the pressurizing unit 110 smaller than the reference pressure, the electric resistance of the current flowing in the stacking direction is increased in the stacking direction at the reference pressure. It becomes larger than the electric resistance of the flowing current.

  The environmental situation includes vibrations acting on the bipolar battery 10. When the vibration detected by the detection unit 173 is equal to or higher than the reference vibration, for example, when the internal combustion engine is started, the controller 170 generates a pressurizing force larger than the pressurizing force in the reference vibration. Control the operation of Since the applied pressure is increased, there is no possibility that the battery element 30 is peeled off, and the electrical resistance is reduced, which is advantageous at the time of starting. Conversely, when the vibration detected by the detection unit 173 is smaller than the reference vibration, the operation of the pressurization unit 110 is controlled so as to generate a pressurizing force that is smaller than the pressurizing force in the reference vibration.

  The environmental situation includes the temperature inside the bipolar battery 10 or the temperature outside the bipolar battery 10. When the temperature detected by the detecting unit 173 is equal to or lower than the reference temperature, the controller 170 controls the operation of the pressurizing unit 110 so as to generate a pressurizing force larger than the pressurizing force at the reference temperature. When the temperature detected by the detecting unit 173 is higher than the reference temperature, the operation of the pressurizing unit 110 is controlled so as to generate a pressurizing force smaller than the pressurizing force at the reference temperature.

  The effect that the applied pressure increases when the detected temperature is lower than the reference temperature has the following advantages. That is, when the bipolar battery 10 is mounted on a device that generates vibration at the time of starting (for example, an automobile equipped with an internal combustion engine), the battery element 30 generally operates as a reference before starting the device. The temperature is lower than the temperature. At this time, a pressing force larger than the pressing force at the reference temperature is applied to the battery element 30. Therefore, even if the vibration accompanying the start of the device is applied to the bipolar battery 10, the battery element 30 can sufficiently resist the vibration, and it is possible to prevent the battery element 30 from being caused by the vibration.

  By performing the control as described above, the electric resistance of the current flowing in the stacking direction of the bipolar battery 10 can be controlled, the variation in the current density can be suppressed, and the deterioration of the bipolar battery 10 due to the variation in the current density is reduced. To do. As a result, the durability of the bipolar battery 10 and thus the power supply device 100 is improved.

  FIG. 8 is a cross-sectional view for explaining a state in which a plurality of bipolar batteries 10 are accommodated in the case 120. Even when a plurality of bipolar batteries 10 are accommodated, the pressure from the fluid can be uniformly applied to the electrode surface. Moreover, a capacity | capacitance and a voltage can be made larger than a cell. The bipolar batteries 10 are connected in series via the terminal plate 103.

  FIG. 9 is a cross-sectional view for explaining a state in which a battery pack 11 including a plurality of bipolar batteries is housed in the case 120. By constituting the assembled battery 11 from a bipolar battery, the battery volume can be reduced and the current extraction mechanism can be simplified.

  Referring to FIGS. 2 and 3, bipolar battery 10 is configured by alternately laminating bipolar electrodes 20 and electrolyte layers 31 and housing battery elements 30 in which these are connected in series in an outer case 40. . In the bipolar electrode 20, a positive electrode active material layer 22 is provided on one surface of a current collector 21 to form a positive electrode 23, and a negative electrode active material layer 24 is provided on the other surface to form a negative electrode 25 (FIG. 3). (See (A)). In the battery element 30 in which the bipolar electrode 20 is laminated, a single battery layer 32 is constituted by the positive electrode active material layer 22, the electrolyte layer 31, and the negative electrode active material layer 24 sandwiched between adjacent current collectors 21 and 21. (See FIG. 3B). The positive electrode terminal electrode 33 of the battery element 30 is provided with only the positive electrode active material layer 22 on one surface of the end current collector 21e, and is laminated on the uppermost bipolar electrode 20 in FIG. Is done. The negative electrode end electrode 34 of the battery element 30 is provided with only the negative electrode active material layer 24 on one surface of the end current collector 21e, and is laminated via the electrolyte layer 31 below the lowest bipolar electrode 20 in FIG. Is done.

  Positive and negative terminals 51 and 52 for taking out current flowing in the surface direction are electrically connected to the respective ends in the stacking direction of the battery element 30. Specifically, the positive electrode terminal 51 is electrically connected to the end current collector 21 e of the positive electrode end electrode 33, and the negative electrode terminal 52 is electrically connected to the end current collector 21 e of the negative electrode end electrode 34. ing. The positive electrode terminal 51 has a size larger than at least the projected area of the positive electrode active material layer 22 of the positive electrode terminal electrode 33, and is superimposed on the end current collector 21e so as to cover the projected surface of the positive electrode active material layer 22. Has been placed. Similarly, the negative electrode terminal 52 has a size larger than at least the projected area of the negative electrode active material layer 24 of the negative electrode terminal electrode 34, and is on the end current collector 21e so as to cover the projected surface of the negative electrode active material layer 24. Is placed on top of each other. The terminals 51 and 52 and the end current collector 21e are electrically evenly joined over the entire projection surface of the active material layers 22 and 24. For this reason, the terminals 51 and 52 receive current uniformly from the entire surface of the end current collector 21e where the current substantially flows, and can suppress variations in current density.

  The configuration of the bipolar battery 40 may be a known material used for a general lithium ion secondary battery, and is not particularly limited. Hereinafter, the terminals 51 and 52, the outer case 40, the current collector 21, the positive electrode 23 (positive electrode active material layer 22), the negative electrode 25 (negative electrode active material layer 24), and the electrolyte layer 31 in the bipolar battery 10 will be further described.

[Positive electrode terminal 51, negative electrode terminal 52]
The terminals 51 and 52 arranged on the end current collector 21e have a function as terminals for taking out current. As the material of the terminals 51 and 52, a material used in a lithium ion battery can be used. For example, aluminum, copper, and other highly conductive materials are preferable. However, even if the material has low conductivity, if the thickness direction is increased, the resistance can be reduced to an acceptable level, and a sufficient flow of electricity in the plane direction can be ensured. Therefore, stainless steel (SUS) or the like having lower conductivity than aluminum or the like can be used. Aluminum is preferably used from the viewpoints of corrosion resistance, ease of production, economy, and the like. The material of the positive electrode terminal 51 and the negative electrode terminal 52 may be the same material or different materials.

  By processing the end portions of the terminals 51 and 52 into a lead shape, the positive electrode lead portion 51 a and the negative electrode lead portion 52 a are formed integrally with the terminals 51 and 52. The positive electrode lead portion 51a and the negative electrode lead portion 52a taken out from the outer case 40 are preferably covered with a heat-shrinkable heat-shrinkable tube or the like. This is to prevent the lead parts 51a and 52a from coming into contact with the heat source when the distance between the lead parts 51a and 52a and the heat source is small, and causing adverse effects on components (particularly electronic devices) due to electric leakage.

  In the first embodiment, the case where the ends of the terminals 51 and 52 are formed in a lead shape is illustrated. However, in the bipolar battery of the present invention, the terminals 51 and 52 themselves extend outward from the outer case 40. You don't have to. The bipolar battery includes, for example, a rectangular terminal that is in planar contact with the end current collector 21e and is accommodated in the outer case 40, and leads that are attached to the terminal by welding and extend outward from the outer case 40. May be. As this lead, a known lead used in a lithium ion battery or the like can be used.

[Exterior case 40]
In the bipolar battery 10, the battery element 30 and the terminals 51, 52 are accommodated in the outer case 40 in order to mitigate impact from the outside during use and prevent environmental degradation. The outer case 40 is formed of a flexible sheet-like material, and seals the battery element 30, the positive terminal 51, and the negative terminal 52. Furthermore, the internal pressure of the outer case 40 is a pressure lower than the atmospheric pressure Pa. The terminals 51 and 52 are merely placed on the end current collector 21e, and mechanical fastening is not performed between them. Conductivity between the terminals 51 and 52 and the end current collector 21e is ensured by metal contact due to pressure acting when sealed by the outer case 40. An adhesive or non-adhesive coating agent excellent in conductivity may be interposed between the terminals 51 and 52 and the end current collector 21e. This is because the metal contact between the two becomes dense and the conductivity is more reliable.

  The sheet-like material may be a flexible material that can be easily deformed without being broken by a pressure difference between the inside and the outside of the outer case 40. The battery element 30 is pressurized from above and below in the figure via the terminals 51 and 52 by hydrostatic pressure using the atmospheric pressure Pa.

  If the connection between the terminals 51 and 52 and the end current collector 21e is electrically non-uniform over the entire surface, the current density varies, which may promote deterioration. In the present embodiment, the relationship between the pressure inside the outer case 40 <the pressure outside the outer case 40 (= atmospheric pressure Pa) is satisfied by the hydrostatic pressure using the atmospheric pressure Pa. And the end current collector 21e are electrically uniform over the entire surface. Therefore, the variation in current density distribution is suppressed, and the promotion of deterioration due to the variation in current density is suppressed. In addition, the output of the battery can be reliably increased by reducing the resistance of the terminals 51 and 52.

  Further, the sheet-like material preferably exhibits electrical insulation without allowing electrolyte or gas to permeate and is chemically stable with respect to the material such as the electrolyte, and examples thereof include synthetic resins such as polyethylene, polypropylene, and polycarbonate. The

  As the sheet material, a laminate film 41 including a metal foil and a synthetic resin film can also be suitably applied. This is because it is preferable for reducing the heat sealing property of the outer case 40 and the possibility of air contact of the electrolyte and further reducing the weight. The laminate film 41 has a three-layer structure in which a metal foil 42 made of a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper is covered with insulating synthetic resin films 43 and 44 such as a polypropylene film. In addition to the polymer-metal composite laminate film 41, an aluminum laminate pack can be used similarly.

  The polymer-metal composite laminate film 41, the aluminum laminate pack and the like are preferably excellent in thermal conductivity. This is because when mounted on an automobile, heat can be efficiently transmitted from the automobile heat source to the bipolar battery 10 and the battery element 30 can be quickly heated to the battery operating temperature.

  When the laminate film 41 is used for the exterior case 40, the battery element 30 and the terminals 51 and 52 are housed and sealed by joining part or all of the periphery of the laminate film 41 by heat fusion. To do. The lead parts 51a and 52a are sandwiched between the heat-sealed parts and exposed to the outside of the laminate film 41.

  If the outer case 40 is applied to the laminate film 41 as in the present embodiment, the outer case 40 is easily deformed, and the hydrostatic pressure using the atmospheric pressure Pa can be applied to the battery element 30. Furthermore, since the layer of the metal foil 42 is present, the gas permeability is lowered, and the pressure difference between the inside and the outside can be maintained over a long period of time. As a result, the terminals 51 and 52 and the end current collector 21e Stable electrical contact can be maintained over a long period of time.

  The case where the terminals 51 and 52 are brought into close contact with the end current collector 21e by hydrostatic pressure using the atmospheric pressure Pa is exemplified. However, in the bipolar battery of the present invention, the pressure inside the outer case 40 <the outer case 40 exterior. As long as the pressure relationship is satisfied, the medium generating the hydrostatic pressure is not limited. For example, the terminals 51 and 52 may be brought into close contact with the end current collector 21e by hydrostatic pressure using at least one medium of gas, liquid, or solid powder, or a medium obtained by mixing them.

[Current collector 21]
The current collector 21 of the present embodiment is made of stainless steel (SUS). Since stainless steel is stable with respect to both the positive electrode active material and the negative electrode active material, the active material layers 22 and 24 can be formed on both the front and back surfaces of the stainless steel single layer.

  In the terminal electrodes 33 and 34, the positive electrode active material layer 22 or the negative electrode active material layer 24 is formed only on one surface of the end current collector 21e.

  The thickness of the current collector 21 is not particularly limited, but is about 1 μm to 100 μm.

[Positive electrode 23 (positive electrode active material layer 22)]
The positive electrode 23 includes a positive electrode active material. In addition to this, a conductive aid, a binder, and the like may be included. The gel electrolyte is sufficiently infiltrated into the positive electrode 23 and the negative electrode 25 by chemical crosslinking or physical crosslinking.

As the positive electrode active material, a composite oxide of transition metal and lithium, which is also used in a solution-type lithium ion battery, can be used. Specifically, Li · Co-based composite oxide such as LiCoO _2, Li · Ni-based composite oxide such as LiNiO _2, Li · Mn-based composite oxide such as spinel LiMn ₂ O _4, Li · such LiFeO ₂ Examples thereof include Fe-based composite oxides. In addition, transition metal and lithium phosphate compounds and sulfuric acid compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned.

  The particle diameter of the positive electrode active material is not limited as long as it can be formed into a paste by spraying the positive electrode material and spray coating or the like in order to reduce the electrode resistance of the bipolar battery 10. What is smaller than the generally used particle size used in the type of lithium ion battery may be used. Specifically, the average particle diameter of the positive electrode active material is preferably 0.1 μm to 10 μm.

  The polymer gel electrolyte is a solid polymer electrolyte having ion conductivity containing an electrolyte solution usually used in a lithium ion battery. Further, in the polymer skeleton having no lithium ion conductivity, In addition, those holding the same electrolytic solution are also included.

Here, the electrolyte solution (electrolyte salt and plasticizer) contained in the polymer gel electrolyte may be any electrolyte solution that is normally used in lithium ion batteries. For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF. ₆ , inorganic acid anion salts such as LiAlCl ₄ and Li ₂ B ₁₀ Cl ₁₀ , organic acid anions such as LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, and Li (C ₂ F ₅ SO ₂ ) ₂ N Including at least one lithium salt (electrolyte salt) selected from ionic salts, cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane Ethers such as 1,2-dimethoxyethane and 1,2-dibutoxyethane; Lactones such as γ-butyrolactone; Nitriles such as acetonitrile; Esters such as methyl propionate; Amides such as dimethylformamide; Methyl acetate Further, those using an organic solvent (plasticizer) such as an aprotic solvent in which at least one selected from methyl formate or a mixture of two or more thereof can be used. However, it is not necessarily limited to these.

  Examples of the polymer having ion conductivity include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

  For example, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), etc. are used as the polymer having no lithium ion conductivity used for the polymer gel electrolyte. it can. However, it is not necessarily limited to these. Note that PAN, PMMA, etc. are in a class that has almost no ionic conductivity. Therefore, the PAN, PMMA, and the like can be used as a polymer having the ionic conductivity described above, but are used here as a polymer gel electrolyte. This is exemplified as a polymer having no lithium ion conductivity.

As the lithium salt, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiTaF 6, LiAlCl 4, Li 2 B 10 Cl 10 and the like inorganic acid anion _{salts, Li (CF 3 SO 2)} 2 N, An organic acid anion salt such as Li (C ₂ F ₅ SO ₂ ) ₂ N or a mixture thereof can be used. However, it is not necessarily limited to these.

  Examples of the conductive assistant include acetylene black, carbon black, and graphite. However, it is not necessarily limited to these.

  In the present embodiment, the electrolyte solution, lithium salt, and polymer (polymer) are mixed to prepare a pregel solution, and the positive electrode 23 and the negative electrode 25 are impregnated.

  The blending amount of the positive electrode active material, the conductive assistant and the binder in the positive electrode 23 should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity. For example, if the amount of the electrolyte in the positive electrode 23, particularly the solid polymer electrolyte, is too small, the ionic conduction resistance and the ionic diffusion resistance in the active material layer will increase, and the battery performance will deteriorate. On the other hand, if the amount of the electrolyte in the positive electrode 23, particularly the solid polymer electrolyte, is too large, the energy density of the battery is lowered. Therefore, in consideration of these factors, the solid polymer electrolytic mass meeting the purpose is determined.

  The thickness of the positive electrode 23 is not particularly limited, and should be determined in consideration of the intended use of the battery (emphasis on output, emphasis on energy, etc.) and ion conductivity, as described for the blending amount. The thickness of the general positive electrode active material layer 22 is about 10 to 500 μm.

[Negative Electrode 25 (Negative Electrode Active Material Layer 24)]
The negative electrode 25 includes a negative electrode active material. In addition to this, a conductive aid, a binder, and the like may be included. Except for the type of the negative electrode active material, the contents are basically the same as those described in the section of “Positive electrode 23”, and thus the description thereof is omitted here.

  As the negative electrode active material, a negative electrode active material that is also used in a solution-type lithium ion battery can be used. For example, metal oxide, lithium-metal composite oxide metal, carbon and the like are preferable. More preferred are carbon, transition metal oxide, and lithium-transition metal composite oxide. More preferred are titanium oxide, lithium-titanium composite oxide, and carbon. These may be used alone or in combination of two or more.

  In the present embodiment, the positive electrode active material layer 22 uses a lithium-transition metal composite oxide as the positive electrode active material, and the negative electrode active material layer 24 uses carbon or a lithium-transition metal composite as the negative electrode active material. An oxide is used. This is because a battery having excellent capacity and output characteristics can be configured.

[Electrolyte layer 31]
The electrolyte layer 31 is a layer composed of a polymer having ion conductivity, and the material is not limited as long as it exhibits ion conductivity.

  The electrolyte of this embodiment is a polymer gel electrolyte. As described above, after impregnating a pregel solution into a separator as a substrate, the electrolyte is used as a polymer gel electrolyte by chemical crosslinking or physical crosslinking.

  Such a polymer gel electrolyte is an all-solid polymer electrolyte having ion conductivity such as polyethylene oxide (PEO) containing an electrolytic solution usually used in a lithium ion battery. A polymer gel electrolyte that contains a similar electrolyte solution in a polymer skeleton having no lithium ion conductivity such as vinylidene (PVDF) is also included. Since these are the same as the polymer gel electrolyte described as a kind of electrolyte contained in the positive electrode 23, description thereof is omitted here. The ratio of the polymer constituting the polymer gel electrolyte to the electrolyte solution is wide. When 100% of the polymer is an all solid polymer electrolyte and 100% of the electrolyte solution is a liquid electrolyte, all of the intermediates correspond to the polymer gel electrolyte. The term “polymer electrolyte” includes both a polymer gel electrolyte and an all solid polymer electrolyte.

  The polymer gel electrolyte can be included in the positive electrode 23 and / or the negative electrode 25 as described above, in addition to the polymer electrolyte constituting the battery. However, the polymer gel electrolyte is different depending on the polymer electrolyte constituting the battery, the positive electrode 23, and the negative electrode 25. Molecular electrolytes may be used, the same polymer electrolyte may be used, or different polymer electrolytes may be used depending on the layer.

  The thickness of the electrolyte constituting the battery is not particularly limited. However, in order to obtain a compact bipolar battery 10, it is preferable to make it as thin as possible within a range that can ensure the function as an electrolyte. The thickness of the general solid polymer electrolyte layer 31 is about 10 to 100 μm. However, the shape of the electrolyte can be easily formed so as to cover the upper surface of the electrode (positive electrode 23 or negative electrode 25) as well as the outer peripheral portion of the side by taking advantage of the manufacturing method. It is not always necessary to have a substantially constant thickness.

  In the bipolar battery 10, when the electrolyte solution contained in the electrolyte layer 31 oozes out, the layers are electrically connected to each other and do not function as a battery. This is called a liquid junction.

  When a liquid or semi-solid gel substance is used for the electrolyte layer 31, it is necessary to seal between the current collectors 21 so that the electrolyte does not leak. Therefore, as shown in FIG. 1, a seal member 36 is provided between the current collectors 21 so as to surround the unit cell layer 32. The seal member 36 is, for example, a double-sided tape in which an adhesive material is applied to both surfaces of a base material. The base material is formed of an insulating resin such as polypropylene (PP), polyethylene (PE), or polyamide synthetic fiber. The pressure-sensitive adhesive is formed of a solvent-resistant material such as synthetic rubber, butyl rubber, synthetic resin, or acrylic. The sealing member 36 prevents liquid leakage from the single cell layer 32 and prevents a short circuit due to contact between the current collectors 21.

  The electrolyte layer 31 can also use a solid electrolyte. This is because by using a solid as the electrolyte, it is possible to prevent liquid leakage, preventing a liquid junction that is a problem peculiar to bipolar batteries, and providing a highly reliable bipolar battery. In addition, since a configuration for preventing leakage is not required, the configuration of the bipolar battery can be simplified.

Examples of the solid electrolyte include known solid polymer electrolytes such as polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. The solid polymer electrolyte layer contains a supporting salt (lithium salt) in order to ensure ionic conductivity. As the supporting salt, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof can be used. However, it is not necessarily limited to these. Polyalkylene oxide polymers such as PEO and PPO can dissolve lithium salts such as LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ well. Moreover, excellent mechanical strength is exhibited by forming a crosslinked structure.

It is sectional drawing which shows the electric power supply apparatus which concerns on embodiment of this invention. It is sectional drawing which shows a bipolar battery. FIG. 3A is a cross-sectional view showing a bipolar electrode, and FIG. 3B is a cross-sectional view for explaining a single cell layer. It is sectional drawing for demonstrating the temperature control part of an electric power supply apparatus. It is sectional drawing for demonstrating the fluid circulation part of an electric power supply apparatus. It is sectional drawing for demonstrating the electrically conductive member which has elasticity. It is sectional drawing for demonstrating a floating member. It is sectional drawing for demonstrating the state which accommodated the several bipolar battery in the case. It is sectional drawing for demonstrating the state which what accommodated the thing which made the some bipolar battery the assembled battery in the case.

Explanation of symbols

10 Bipolar battery,
11 assembled battery 20 bipolar electrode,
21 current collector,
23 positive electrode,
25 negative electrode,
30 battery elements,
30a laminate,
31 electrolyte layer,
32 cell layer,
36 sealing member,
40 exterior case,
100 power supply device,
110 Pressurizing part,
111 pressure regulator,
120 cases,
130 fluid,
140 temperature adjustment unit,
141 heat sink,
150 fluid circulation section,
151 pump,
160 floating member,
162 conductive members,
170 controller (control unit),
171 Vibrometer,
172 temperature sensor,
173 detector.

Claims (15)

At least one bipolar battery in which current flows in the direction of lamination of the bipolar electrodes;
A pressure applied as a reference for pressurizing the bipolar battery in the stacking direction is set, and a pressure adjusted with respect to the pressure applied as the reference is set in accordance with an environmental condition acting on the bipolar battery. A pressurizing part for energizing the battery ;
A case for accommodating the bipolar battery,
The said pressurization part is an electric power supply apparatus which has the fluid which exists between the said bipolar battery and the said case . The power supply apparatus according to claim 1, wherein the pressurizing unit includes a pressure adjusting unit that adjusts a pressure of the fluid . The power supply apparatus according to claim 1 , wherein the fluid also functions as a refrigerant for cooling the bipolar battery . The power supply apparatus according to claim 1 , further comprising a temperature adjusting unit that adjusts a temperature of the fluid . The power supply apparatus according to claim 1 , further comprising a fluid circulation unit that circulates the fluid between the inside of the case and the outside of the case . The power supply device according to claim 1 , wherein the fluid is an incompressible and hydrophobic fluid . The power supply device according to claim 1, wherein the fluid exists between at least one of both end surfaces of the bipolar battery in the stacking direction and the case . The power supply device according to claim 1 , further comprising a floating member that prevents each of both end surfaces of the bipolar battery in the stacking direction from coming into contact with an inner surface of the case . The power supply device according to claim 1 , further comprising a conductive member that is disposed between the bipolar battery and the case and extracts an electric current and has elasticity . A detection unit for detecting an environmental condition acting on the bipolar battery;
A control unit for controlling the operation of the pressurizing unit,
The power supply device according to claim 1 , wherein the control unit controls an electric resistance of a current flowing in the stacking direction by controlling the pressurizing force based on the environmental state detected by the detection unit. 2. The power supply device according to claim 1 , wherein the environmental condition includes at least one of vibrations acting on the bipolar battery, a temperature inside the bipolar battery, or a temperature outside the bipolar battery . The environmental condition is a vibration acting on the bipolar battery, or a temperature inside or outside the bipolar battery,
The pressurizing part is
When the vibration acting on the bipolar battery is greater than or equal to the reference vibration, a force greater than the pressure applied in the reference vibration is applied to the bipolar battery, and the vibration acting on the bipolar battery is more than the reference vibration. When the pressure is smaller than the bias voltage in the reference vibration, the bipolar battery is energized, or
When the internal or external temperature of the bipolar battery is equal to or lower than a reference temperature, a pressure larger than the reference pressure is applied to the bipolar battery, and the internal or external temperature of the bipolar battery is the reference temperature. 2. The power supply device according to claim 1 , wherein when the temperature is higher than a temperature at which the pressure is higher, a pressure smaller than a pressure at a reference temperature is applied to the bipolar battery .   When pressurizing at least one bipolar battery in which current flows in the stacking direction of the bipolar electrode in the stacking direction, a pressing force is set as a reference for pressurizing in the stacking direction. In response, the bias pressure adjusted with respect to the reference pressure is urged to the bipolar battery,
  A method of controlling a power supply apparatus, wherein the pressure is adjusted by a fluid pressure interposed between the bipolar battery and a case housing the bipolar battery. The method of controlling a power supply apparatus according to claim 13, wherein the bipolar battery is cooled by the fluid . The environmental condition is a vibration acting on the bipolar battery, or a temperature inside or outside the bipolar battery,
When the vibration acting on the bipolar battery is greater than or equal to the reference vibration, a force greater than the pressure applied in the reference vibration is applied to the bipolar battery, and the vibration acting on the bipolar battery is more than the reference vibration. When the pressure is smaller than the bias voltage in the reference vibration, the bipolar battery is energized, or
When the internal or external temperature of the bipolar battery is equal to or lower than a reference temperature, a pressure larger than the reference pressure is applied to the bipolar battery, and the internal or external temperature of the bipolar battery is the reference temperature. 14. The method of controlling a power supply apparatus according to claim 13 , wherein when the temperature is higher than a temperature at which the pressure is higher, a pressure smaller than a pressure at a reference temperature is urged to the bipolar battery .

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