JP6634676B2 - Battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a battery having a function of protecting a battery, particularly, from overcharging, and a method for manufacturing the battery.

  Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries have already been put into practical use as batteries for notebook computers and mobile phones due to their advantages such as high energy density, low self-discharge, and excellent long-term reliability. I have. However, in recent years, electronic devices have been improved in functionality and used for electric vehicles, and the development of lithium ion secondary batteries with higher energy density has been demanded.

  On the other hand, as the energy capacity or energy density of the battery increases, the temperature of the battery increases when a short circuit occurs due to an external impact or a circuit failure, or when the battery is overcharged. When the battery is overcharged, the battery generates excessive heat, causing an oxygen release reaction of the active material and a thermal decomposition reaction of the electrolytic solution, and the battery further generates heat. It can also lead.

  Therefore, various proposals have conventionally been made to suppress excessive temperature rise of the battery due to overcharging or the like. For example, Patent Literature 1 (WO 2012/172592) describes a battery including a redox shuttle agent in an electrolyte. When the positive electrode potential exceeds the reaction potential of the redox shuttle agent during charging, the redox shuttle agent repeats an oxidation-reduction reaction between the positive electrode and the negative electrode, and consumes an overcharge current. As a result, the battery voltage is prevented from reaching a certain value or more depending on the reaction potential of the redox shuttle agent, and as a result, overcharging is prevented.

International Publication No. 2012/172592

  The structure described in Patent Literature 1 uses a redox shuttle agent that causes an oxidation-reduction reaction when the potential difference between the positive electrode and the negative electrode exceeds a predetermined value, and can effectively suppress overcharge. However, since the redox shuttle agent is sealed in the battery case together with the electrode element, there is a possibility that the performance of the battery may be affected such as deterioration of battery characteristics and increase in internal leak current. Further, redox shuttle agents having an appropriate oxidation-reduction potential are limited. That is, it is difficult to use a redox shuttle agent that operates at a potential lower than the battery potential, and a redox shuttle agent that operates at a potential higher than the battery potential is exposed to a high potential. However, there is a problem that the battery performance may be deteriorated due to this.

  Accordingly, an object of the present invention is to provide a battery that can more reliably suppress overcharge without affecting the performance of the battery.

According to one embodiment of the present invention, a battery element to which a positive electrode terminal and a negative electrode terminal are connected,
An inter-terminal cell connected in parallel between the positive terminal and the negative terminal,
Has,
The inter-terminal cell is a container in which a redox shuttle agent that causes an oxidation-reduction reaction at a specific potential or higher is enclosed,
At least a portion disposed inside the container, at least one first electrode connected to the positive electrode terminal and at least one second electrode connected to the negative electrode terminal;
A battery having:

  It is preferable that the battery further includes an element having a non-linear current-voltage characteristic, which is connected in series to the inter-terminal cell.

According to another aspect of the present invention, a step of connecting the positive electrode terminal and the negative electrode terminal to the battery element,
A container enclosing a redox shuttle agent that causes an oxidation-reduction reaction at a specific potential or higher, and at least one first electrode connected to the positive electrode terminal and the negative electrode terminal at least partially disposed inside the container; Producing an inter-terminal cell having at least one second electrode connected to:
Connecting the inter-terminal cell in parallel between the positive terminal and the negative terminal,
A method for manufacturing a battery having the following is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the overcharge of a battery can be prevented using the reaction of a redox shuttle agent, without affecting the characteristics of a battery.

FIG. 1 is a diagram schematically illustrating a configuration of a battery according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating an example of an internal structure of the redox shuttle cell illustrated in FIG. 1. FIG. 2 is an equivalent circuit diagram when the redox shuttle cell has a resistance component in the battery shown in FIG. 1. FIG. 11 is an equivalent circuit diagram of a redox shuttle cell according to another embodiment of the present invention, further including an element having a non-linear current-voltage characteristic. 5 is a graph showing current-voltage characteristics of a redox shuttle cell used in an operation simulation of the circuit shown in FIG. 5 is a graph showing current-voltage characteristics of a diode used in an operation simulation of the circuit shown in FIG. 5 is a current-voltage characteristic graph showing an operation simulation result of the circuit shown in FIG. FIG. 4 is a schematic cross-sectional view illustrating a structure of a battery element included in a stacked secondary battery. FIG. 1 is a schematic diagram illustrating an example of an electric vehicle including a battery of the present invention. It is a schematic diagram which shows an example of the electrical storage equipment provided with the battery of this invention.

  Referring to FIG. 1, a battery 1 according to one embodiment of the present invention is schematically shown. The battery 1 includes a battery element 10, an exterior body 13 that seals the battery element 10, and a positive electrode terminal 11 and a negative electrode terminal 12 that are electrically connected to the battery element 10 and extend outside the exterior body 13. ing. The exterior body 13 is made of a flexible exterior material, for example, a laminate film, and seals the battery element 10 by heat-welding the outer periphery while surrounding the battery element 10. The battery element 10 includes a positive electrode, a negative electrode, a separator, and an electrolytic solution. The battery element 10, the positive electrode terminal 11, the negative electrode terminal 12, and the package 13 can be configured in the same manner as a conventional battery.

  The battery 1 further includes a redox shuttle cell 15 which is an inter-terminal cell in the present invention outside the exterior body 13. The redox shuttle cell 15 has a function of suppressing a voltage rise so as not to be in an overcharged state. Here, “overcharge” means that the battery is excessively heated by being charged more than usual, and in some cases, a thermal runaway occurs in which temperature control becomes impossible.

  The redox shuttle cell 15 has at least one first electrode 17a and at least one second electrode 17a extending from the container 16 and electrically connected to the positive electrode terminal 11 and the negative electrode terminal 12, respectively. It has an electrode 17b. The first electrode 17a and the second electrode 17b are partially apart from each other in the container 16, and are usually insulated from each other. Here, the insulated state refers to a state in which electrons do not come and go, that is, a so-called “short circuit” occurs due to direct contact between the two electrodes, for example, a redox shuttle agent, an electrolyte solution molecule, lithium ion And the like may be able to move relatively freely according to the potential between the electrodes, the concentration difference, and the like. In the redox shuttle agent, when the potential of the first electrode 17a connected to the positive electrode terminal 11 becomes higher than the oxidation potential in the oxidation reaction according to the type of the redox shuttle agent, the oxidation reaction at the first electrode 17a becomes remarkable. Since the reaction product generated from the redox shuttle agent returns to the original compound by the reduction reaction at the second electrode 17b, the oxidation-reduction reaction is repeated between the positive electrode and the negative electrode. The container 16 may be any as long as it can encapsulate the redox shuttle agent. For example, the container 16 is formed of a flexible laminated film or the like, like the exterior body 13 that seals the battery element 10. It can be a can or a can.

  Examples of the redox shuttle agent include an aromatic compound, a heterocyclic complex, a metallocene complex such as ferrocene, a Ce compound, and a radical compound. In addition, as the redox shuttle agent, only one kind can be used alone, or two or more kinds can be used in combination.

  Specific compounds include, for example, 3,4-difluoroanisole, 2,4-difluoroanisole, 1-methoxy-2,3,4,5,6-pentafluorobenzene, 2,3,5,6-tetra Fluoroanisole, 4- (trifluoromethoxy) anisole, 3,4-dimethoxybenzonitrile, 1,2,3,4-tetrachloro-5,6-dimethoxybenzene, 1,2,4,5-tetrachloro-3 , 6-Dimethoxybenzene 4-fluoro-1,2-dimethoxybenzene, 4-bromo-1,2-dimethoxybenzene, 2-bromo-1,4-dimethylbenzene, 1-bromo-3-fluoro-4-methoxybenzene , 2-bromo-1,3-difluoro-5-methoxybenzene, 4,5-difluoro-1,2-dimethoxybenzene, 2,5-difluoro -1,4-dimethoxybenzene, 1,2,3,4-tetrachloro-5,5-dimethoxycyclopentadiene, 1,2,4-trimethoxybenzene, 1,2,3-trimethoxybenzene, 2,5 -Di-tert-butyl-1,4-dimethoxybenzene, 4-tert-butyl-1,2-dimethoxybenzene, 1,4-ditetrabutyl-2,5-trifluoromethoxybenzene, 1,2-ditetrabutyl-4, Homocyclic compounds having one or more electron-withdrawing or electron-donating substituents such as 5-trifluoromethoxybenzene; 4-chloro-1,2-methylenedioxybenzene, 4-bromo-1, 2-methylenedioxybenzene, 3,4-methylenedioxybenzonitrile, 4-nitro-1,2-methylenedioxybenzene, 2-chloro-5 A heterocyclic compound such as methoxypyrazine; a radical compound such as a nitroxyl radical compound; a cerium compound such as cerium nitrate; a metallocene complex such as a ferrocene complex; .

  The redox shuttle agent is a compound that can be uniformly dissolved or dispersed in the non-aqueous electrolyte, and can be appropriately selected according to the maximum potential of the positive electrode required in the redox shuttle cell 15. Each of these compounds has a reaction potential corresponding to the compound. When the potential is higher than the potential, the oxidation reaction rate is significantly increased. For example, 2,5-di-tert-butyl-1,4-dimethoxybenzene has a reaction potential of about 3.9 V, and 4-bromo-1,2-dimethoxybenzene has a reaction potential of about 4.3 V.

  At the time of charging with a constant current, when the voltage between the positive and negative electrodes of the battery 1 becomes high and the redox shuttle agent in the redox shuttle cell 15 is exposed to a potential higher than the reaction potential, the redox shuttle agent reacts. Then, the oxidation-reduction reaction is repeated with the negative electrode. The current flowing through the battery 1 is suppressed according to the reaction amount.

  Aromatic compounds having one or more alkoxy groups (methoxybenzenes and dimethoxybenzenes) have excellent chemical stability of an oxidant generated by an oxidation reaction, and thus have a reduced battery performance due to a side reaction or the like. Can be suppressed. Further, a compound having a halogen atom has a high redox reaction potential and can be applied to a positive electrode having a higher oxidation-reduction potential, that is, a secondary battery having a higher energy density.

  In the battery 1 configured as described above, when the battery voltage increases during charging of the battery 1 and the potential of the first electrode 17a becomes equal to or higher than the reaction potential of the redox shuttle agent, the first electrode 17a in the container 16 and the second electrode 17a The oxidation-reduction reaction is repeated with the electrode 17b. Thereby, as long as the maximum allowable current of the redox shuttle cell 15 is not exceeded, the voltage between the electrodes at both ends of the container 16 (between the first electrode 17a and the second electrode 17b) can be kept substantially constant. At that time, a current flows through the redox shuttle cell 15 and is consumed, so that the voltage between the positive electrode terminal 11 and the negative electrode terminal 12 is suppressed from becoming a certain value or more depending on the reaction potential of the redox shuttle agent, As a result, overcharging of the battery 1 is prevented. Note that the maximum allowable current is that when a current flows through the redox shuttle cell 15, the voltage between the first electrode 17a and the second electrode 17b converges to a substantially constant value on the time axis and maintains that voltage. This is the maximum value of the current that can be generated.

  Whether the oxidation-reduction reaction by the redox shuttle agent has occurred in the redox shuttle cell 15 during the charging of the battery 1 is determined by the reaction potential of the redox shuttle agent even when the battery 1 is continuously charged at a current equal to or less than the maximum allowable current. Can be confirmed by the fact that the voltage no longer rises above a certain voltage corresponding to. Specifically, when a graph in which the horizontal axis is time and the vertical axis is the voltage of the battery 1 is drawn, the drawn voltage rising curve becomes parallel to the horizontal axis, and if the state continues, it is a redox shuttle cell. It may be considered that an oxidation-reduction reaction by the redox shuttle agent has occurred in 15. When the decomposition of the electrolytic solution starts, the voltage rise may temporarily stop, but in this case, gas is generated by decomposition of the electrolytic solution, or decomposition products of the electrolytic solution adhere to the electrode surface. Therefore, the cell volume and the internal resistance increase rapidly. Therefore, it is possible to distinguish between the oxidation-reduction reaction caused by the redox shuttle agent and the phenomenon caused by decomposition of the electrolytic solution. Therefore, the phenomenon that the voltage of the battery 1 does not increase even if the charging is continued is a peculiar phenomenon caused by the repetition of the oxidation-reduction reaction by the redox shuttle agent during the charging of the battery 1.

  However, when the charging current when charging the battery element 10 is large, the increase in voltage may not be zero even if the redox shuttle agent causes an oxidation-reduction reaction. When the voltage rise is thus observed, the voltage rise curves are compared between a state where the redox shuttle cell 15 is connected to the positive terminal 11 and the negative terminal 12 of the battery 1 and a state where the redox shuttle cell 15 is removed. do it. When a redox shuttle agent causes an oxidation-reduction reaction, a difference is seen in the voltage rise curves between the two. Specifically, when an oxidation-reduction reaction is caused by the redox shuttle agent, the rate of increase in voltage is smaller when the redox shuttle cell 15 is connected.

  As described above, by connecting the redox shuttle cell 15 containing the redox shuttle agent between the positive electrode terminal 11 and the negative electrode terminal 12, the battery 1 can be prevented from being overcharged. In addition, the redox shuttle cell 15 is provided outside the exterior body 13 that seals the battery element 10, and separates the battery element 10 from the redox shuttle agent. Therefore, the positive electrode, the negative electrode, the separator, and the electrolyte constituting the battery element 10 are not affected by the redox shuttle agent, so that the redox shuttle agent does not deteriorate the battery characteristics.

  The redox shuttle cell 15 generates heat when the redox shuttle agent repeats an oxidation-reduction reaction and consumes current. By utilizing this heat generation, when the battery 1 is charged to exceed the current consumption capability of the redox shuttle agent, the heat causes a short circuit between the positive electrode terminal 11 and the negative electrode terminal 12 to release the energy of the battery 1. The redox shuttle cell 15 can also be configured as described above.

  FIG. 2 shows an example of such a redox shuttle cell 15. The redox shuttle cell 15 shown in FIG. 2 further has an insulating member 19 accommodated in a container 16. The first electrode 17a and the second electrode 17b are opposed to each other in the container 16 in a positional relationship where the first electrode 17a and the second electrode 17b partially overlap each other. The insulating member 19 is a sheet-shaped member, and is disposed between the first electrode 17a and the second electrode 17b to insulate the two electrodes. An end 19 a of the insulating member 19 is fixed to the container 16. The insulating member 19 has a heat-shrinking property or a heat-melting property, and shrinks or melts by heat generated when the redox shuttle agent sealed in the container 18 repeats the oxidation-reduction reaction, and the shrinking or melting causes. The first electrode 17a and the second electrode 17b can be short-circuited. In order to favorably cause a redox shuttle agent oxidation-reduction reaction between the first electrode 17a and the second electrode 17b, the insulating member 19 must be capable of being retained by impregnating the redox shuttle agent. Is preferred. As such an insulating member 19, a film having the same configuration as the separator used in the battery element 10, for example, a microporous film can be used.

  As the insulating member 19, in addition to the microporous film similar to the battery separator, a heat-shrinkable film provided with holes or slits so that the redox shuttle agent can move between the redox shuttle cell electrodes 17 can be used. . As the heat-shrinkable film, for example, a film stretched at a glass transition temperature or higher, such as polyethylene, polypropylene, or polyethylene terephthalate, can be used.

  Alternatively, as the insulating member 19, a film of a shape memory polymer whose shape is fixed by being stretched at a predetermined temperature or higher and cooled while maintaining the strain can be used. When the shape memory polymer is heated again, the shape before stretching is restored. Holes and slits are provided in the shape memory polymer film so that the redox shuttle agent can move between the first electrode 17a and the second electrode 17b. Since the shape memory polymer recovers to its original shape regardless of the stretched shape, the positional relationship between the insulating member 19 and the first electrode 17a and the second electrode 17b can be designed with a higher degree of freedom compared to a stretched film. it can. Shape memory polymers based on polyester, polyurethane, polyisoprene, styrene-butadiene copolymer, and the like have been developed.

  When a shape memory polymer is used in the present invention, the temperature at which the shape is restored when heated is higher than the upper limit operating temperature of the battery, and the heat resistant temperature of the battery member, particularly, preferably lower than the heat resistant temperature of the separator. Specifically, the temperature is preferably from 90 ° C to 150 ° C. For example, Japanese Patent No. 5522513 discloses a shape memory polymer material having a shape recovery temperature of 90 ° C. or higher.

  The insulating member 19 is not limited to a film shape. For example, a plurality of particles made of a thermoplastic insulating material disposed between the opposing first electrode 17a and second electrode 17b can be used as the insulating member 19. These particles function as spacers for maintaining the interval between the first electrode 17a and the second electrode 17b so that the first electrode 17a and the second electrode 17b do not contact each other, and insulate the first electrode 17a and the second electrode 17b. The redox shuttle agent can move between the first electrode 17a and the second electrode 17b through the space between the particles. The particles that are the insulating members 19 are heated by the heat generated by the redox shuttle agent repeating the oxidation-reduction reaction, and are deformed to reduce the height, whereby the first electrode 17a and the second electrode 17b can be short-circuited. it can.

  The particles of the insulating member 19 preferably have a softening point or a melting point of 90 ° C. or more and 150 ° C. or less so that the first electrode 17a and the second electrode 17b are short-circuited before the battery undergoes thermal runaway. As the particles that are the insulating member 19, for example, polyethylene can be used.

  The particles serving as the insulating member 19 are not limited to the spherical shape, but may be a polyhedron. The particle size is preferably 20 μm or more so that reliable insulation can be maintained. In addition, when large particles are used, the distance between the first electrode 17a and the second electrode 17b increases, and heat generation due to an oxidation-reduction reaction of a redox shuttle agent described later decreases. Therefore, the particle diameter is preferably 0.1 mm or less.

  In order to better short-circuit the first electrode 17a and the second electrode 17b due to the deformation of the particles as the insulating member 19, at least one of the opposing surfaces of the first electrode 17a and the second electrode 17b has at least one convex. It is preferable that the particles have a portion and the grains are arranged in a place other than the convex portion. When at least one of the first electrode 17a and the second electrode 17b has a convex portion, when the height of the grains is deformed to a height equal to or less than the height of the convex portion, the height of the grain is reduced at the position where the convex portion is formed. The first electrode 17a and the second electrode 17b can be short-circuited. The height of the protrusions is determined by the height of the particles of the thermoplastic insulating material so that the first electrode 17a and the second electrode 17b come into contact at a predetermined temperature when the particles of the thermoplastic insulating material are softened and deformed by heat. This is set according to the relationship between the first electrode 17a and the second electrode 17b. When the height of the convex portion increases, the average distance between the opposing first electrode 17a and second electrode 17b increases. , Less than 0.1 mm.

  According to the redox shuttle cell 15 configured as described above, the redox shuttle agent suppresses an increase in voltage when overcharged, and uses the charging energy as heat energy to provide the battery element 10 with The positive electrode terminal 11 and the negative electrode terminal 12 can be short-circuited before the contained active material becomes overcharged. Thereby, the energy stored in the battery element 10 can be released. As a result, it is possible to make it difficult for the battery 1 to be ruptured due to ignition due to excessive heat generation and an increase in the internal pressure of the exterior body 13 due to vaporization of the electrolyte.

  Further, even when the temperature around the battery 1 rises, the positive electrode terminal 11 and the negative electrode terminal 12 can be short-circuited, so that even when the battery 1 is exposed to a high temperature, the energy of the battery element 10 is released. be able to. As a result, thermal runaway of the battery 1 can be suppressed.

  In the redox shuttle cell 15 having a short-circuit function between terminals, it is preferable that an electric resistance component is provided between the positive terminal 11 and the negative terminal 12. When the maximum current flowing through the redox shuttle cell 15 is set to be smaller than the maximum allowable current of the redox shuttle cell 15, the magnitude of the electric resistance component is appropriately set so that the positive electrode terminal 11 and the negative electrode terminal It is possible to set the maximum voltage value between them, that is, the upper limit value of the battery voltage. For example, when the current-voltage characteristic during charging is represented by a graph with the horizontal axis representing voltage and the vertical axis representing current, the smaller the value of the electric resistance component, the greater the slope of the graph. Therefore, when charging with a constant current value, the smaller the value of the electric resistance component, the smaller the maximum voltage value, and the larger the value of the electric resistance component, the larger the maximum voltage value.

  In particular, when the redox shuttle cell 15 includes the insulating member 19, it is preferable that the redox shuttle cell 15 has an electric resistance component in a short-circuit path generated by thermal contraction or thermal melting of the insulating member 19. By having the electric resistance component in the short-circuit path, it is possible to limit the current discharged from the battery element 10 due to the short-circuit so as not to be excessive. The electrical resistance component can be provided by forming a resistor on at least one surface of the first electrode 17a and the second electrode 17b, or a resistor is provided on at least one of the first electrode 17a and the second electrode 17b. It can also be provided by connecting in series.

  FIG. 3 shows an equivalent circuit when the redox shuttle cell 15 shown in FIG. 3, the DC power supply corresponds to the battery element 10, and the switch corresponds to a combination of the first electrode 17a, the second electrode 17b, and the insulating member 19.

  An element having a non-linear current-voltage characteristic (IV characteristic) can be connected in series to the redox shuttle cell 15. FIG. 4 shows an equivalent circuit diagram in that case.

  The redox shuttle cell 15 shown in FIG. 4 includes an element 21 having a non-linear IV characteristic in addition to the above-described first electrode 17a, second electrode 17b (in some cases, an insulating member 19) and a resistance component 20. They are connected in series. As such an element 21, for example, an arbitrary element having a non-linear IV characteristic such as a diode, a zener diode, and a varistor can be used. In addition, the number of the elements 21 may be arbitrary, may be one, or a plurality may be arranged in series or in parallel as needed.

  By connecting the element 21 having the non-linear IV characteristic to the redox shuttle cell 15 in this way, the oxidation-reduction reaction of the redox shuttle agent can be generated at a voltage different from the reaction potential of the redox shuttle agent. Therefore, the element 21 can be said to be an operating voltage adjusting element. This means that, for example, even when a redox shuttle agent having a reaction potential of 3.8 V is used, a circuit that operates at a higher voltage, for example, a relatively high voltage of 4.3 V or more can be configured. Means This makes it possible to support batteries of various driving voltages, and increases the degree of freedom in selecting the material of the redox shuttle agent. Furthermore, since a redox shuttle agent having a high oxidation-reduction potential tends to be easily deteriorated, the fact that a redox shuttle agent having a low oxidation-reduction potential can be used is advantageous in terms of extending the life of the redox shuttle cell 15.

  The characteristics of the element 21 to be used can be determined according to the target operating voltage, the magnitude of the current flowing through the circuit, and the like. For example, one of the important characteristics of the element 21 is that it can operate at an assumed charging current. The element 21 preferably has high nonlinearity, that is, the current is sufficiently small below a certain voltage (threshold voltage) at which the IV characteristic changes, and the current is sufficiently high above the threshold voltage. If a single element 21 cannot provide a sufficient current above the threshold voltage at which the IV characteristic changes, a circuit in which a plurality of elements 21 are connected in parallel can be configured to increase the maximum current. Considering that the element 21 is connected in series to the redox shuttle cell, it is preferable to select an element that operates at an appropriate threshold voltage (generally, about 1.5 V or less) depending on the design. Further, if necessary, a plurality of the elements 21 can be connected in series to increase the threshold voltage. In order to reduce the leakage current during normal operation, the element 21 is required to have a small leakage current at a threshold voltage or less.

  An operation simulation result when a diode is connected in series as an operating voltage adjusting element to the redox shuttle cell will be described below.

  In the simulation, a circuit shown in FIG. 4 in which a redox shuttle cell 15, two elements (diodes) 21, and a resistance component 20 were connected in series was assumed. The redox shuttle cell 15 is assumed to be an ideal redox shuttle cell having an operating voltage of 3.8 V as shown in FIG. It is assumed that the element (diode) 21 has the IV characteristics shown in FIG. The resistance value of the resistance component 20 was 50 mΩ.

  In the simulation, a voltage drop at a common current value is calculated from each of the above characteristics, a voltage in the entire circuit is obtained, and this calculation is repeated while changing the current value, whereby the current in the circuit shown in FIG. -Voltage characteristics were calculated. The calculated current-voltage characteristics are shown in the graph of FIG. FIG. 7A shows the entire calculation result, and FIG. 7B shows the calculation result up to a current value of around 1 A, with the vertical axis scale enlarged. Note that the calculation does not take into account the heat generated by each element due to the current flowing through the circuit.

  The simulation results show that a redox shuttle cell having an operating voltage of 3.8 V can provide a circuit that operates at around 5 V. The voltage to which the battery to be protected is charged depends on the charging current for the battery. In the case of the circuit in which the above simulation is performed, the voltage is 10 A at 5.86 V. Therefore, when the battery is charged at 10 A, the voltage does not increase to 5.86 V or more. When the battery is charged at 1 A, the voltage does not rise to 5.2 V or more. Therefore, when the above-described circuit is connected in parallel to a 10 Ah battery cell, the maximum voltage at the time of charging is 5.86 V at 1 C charging and 5.2 V at 0.1 C charging.

  The present invention has been described with reference to the typical embodiments. The present invention is not limited to the above-described embodiment, but can be preferably applied to a lithium ion secondary battery. Further, the redox shuttle cell of the present invention has the same configuration as the battery in that the redox shuttle cell paired with the redox shuttle cell is opposed to each other while being insulated. Therefore, the redox shuttle cell in the present invention can also use the configuration of the secondary battery described below. Specifically, the materials and configurations of the “separator”, “positive electrode current collector / negative electrode current collector”, and “exterior body” described below are the “insulating member”, “first electrode / It can be used for the “second electrode” and the “container”. In this case, the redox shuttle agent can be contained in the “electrolyte solution” described below. As will be apparent from the following description, a redox shuttle cell can have a plurality of first electrodes and a plurality of second electrodes. In this case, as long as the first electrode and the second electrode face each other via the insulating member, the number of the first electrodes and the number of the second electrodes may be different.

  Further, the “first electrode” and the “second electrode” that face each other with the “insulating member” therebetween may be coated with a “positive electrode active material” and a “negative electrode active material”, respectively. If the redox shuttle cell does not have a short-circuit function, any of the separators described below can be used.The separator has heat shrinkability or heat fusibility, and is generated by repeated oxidation-reduction reactions of the redox shuttle agent. By using a material that shrinks or melts due to heat generated, a short-circuit function can be provided.

  There are various types of secondary batteries, such as a cylindrical type, a flat wound square type, a laminated square type, a coin type, a flat wound laminated type, and a laminated laminated type, depending on the structure and shape of the electrode. The present invention is applicable to any of these types. Among these, the shape of the secondary battery to which the present invention is applied is preferably a laminate type from the viewpoint of excellent heat dissipation when the battery element generates heat. Hereinafter, the laminated battery of the laminated type will be described.

A stacked-laminated secondary battery has a battery element and an exterior body that seals the battery element. As shown in FIG. 8, the battery element may have a configuration in which a plurality of negative electrodes a and a plurality of positive electrodes c are alternately stacked with a separator b interposed therebetween. The electrolytic solution is sealed in the package together with the negative electrode a, the positive electrode c, and the separator b. The negative electrode a has an extension (also called a tab) protruding from the separator b. The extension is an end of the negative electrode current collector d of the negative electrode a that is not covered with the positive electrode active material. Similarly, in the positive electrode c, an extension (tab), which is an end of the positive electrode current collector e of the positive electrode c that is not covered with the positive electrode active material, protrudes from the separator b. The extension of the positive electrode c and the extension of the negative electrode a are formed at positions where they do not interfere with each other when the positive electrode c and the negative electrode a are stacked. The extensions of all the negative electrodes a are collected together and connected to the negative electrode terminal g by welding. Similarly, for the positive electrode c, the extensions of all the positive electrodes c are collected together and connected to the positive terminal f by welding.

  Hereinafter, each of these elements will be described in detail by taking a lithium ion secondary battery as an example.

<Separator>
Examples of the separator include webs and sheets made of organic materials, for example, woven fabrics of polyamide, polyimide, cellulose, etc., nonwoven fabrics, polyolefins such as polyethylene and polypropylene, polyamides, polyimides, and porous polymer films such as porous polyvinylidene fluoride films. Alternatively, an ion-conductive polymer electrolyte membrane or the like can be used. These can be used alone or in combination.

In addition, a separator made of an inorganic material such as ceramic or glass can be used as the separator. Examples of the inorganic separator include a nonwoven fabric separator made of ceramic short fibers such as alumina, alumina-silica, and potassium titanate, or a base material made of a woven fabric, a nonwoven fabric, or a porous film, and a heat-resistant nitrogen-containing aromatic polymer and ceramic. A separator comprising a layer containing a powder, or a heat-resistant layer is provided on part of the surface, and the heat-resistant layer is a porous thin film layer containing a ceramic powder, a porous thin film layer of a heat-resistant resin, or a ceramic. A porous thin-film layer separator composed of a composite of powder and heat-resistant resin, or a porous membrane formed by binding secondary particles obtained by sintering or dissolving and recrystallizing a part of primary particles of a ceramic substance with a binder Or a base layer composed of a polyolefin porous membrane, and formed on one or both sides of the base layer With a heat-resistant insulating layer, the heat-resistant insulating layer includes a separator containing oxidation-resistant ceramic particles and a heat-resistant resin, or a porous film formed by combining a ceramic material and a binder, as a ceramic material, Silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), nitride of silicon (Si), hydroxide of aluminum (Al), zirconium (Zr ), A separator using a titanium (Ti) ketone compound, or a polymer substrate, and Al ₂ O ₃ , MgO, TiO ₂ , Al (OH) ₃ , Mg ( And a separator including a ceramic-containing coating layer of OH) ₂ and Ti (OH) ₄ .

<Negative electrode>
The negative electrode has a negative electrode current collector formed of a metal foil, and a negative electrode active material applied to both surfaces of the negative electrode current collector. The negative electrode active material is bound by a negative electrode binder so as to cover the negative electrode current collector. The negative electrode current collector is formed to have an extension connected to the negative electrode terminal, and the extension is not coated with the negative electrode active material.

  The negative electrode active material in the present embodiment is not particularly limited, for example, a carbon material capable of occluding and releasing lithium ions, a metal alloyable with lithium, a metal oxide capable of occluding and releasing lithium ions, and the like. Is mentioned.

  Examples of the carbon material include carbon, amorphous carbon, diamond-like carbon, carbon nanotube, and a composite thereof. Here, carbon having high crystallinity has high electric conductivity, and has excellent adhesion to a negative electrode current collector made of a metal such as copper and excellent voltage flatness. On the other hand, amorphous carbon having low crystallinity has a relatively small volume expansion, so that the effect of alleviating the volume expansion of the entire negative electrode is high, and deterioration due to non-uniformity such as crystal grain boundaries and defects hardly occurs.

  Examples of the metal include Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, and alloys of two or more of these. These metals or alloys may be used as a mixture of two or more. Also, these metals or alloys may include one or more non-metallic elements.

  Examples of the metal oxide include silicon oxide, aluminum oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and a composite thereof. The negative electrode active material preferably contains tin oxide or silicon oxide, and more preferably contains silicon oxide. This is because silicon oxide is relatively stable and hardly causes a reaction with another compound. Further, it is preferable that all or a part thereof has an amorphous structure. It is considered that the amorphous structure has relatively few elements caused by non-uniformity such as crystal grain boundaries and defects. Note that the whole or part of the metal oxide has an amorphous structure can be confirmed by X-ray diffraction measurement (general XRD measurement). Specifically, when the metal oxide does not have an amorphous structure, a peak specific to the metal oxide is observed. However, when all or a part of the metal oxide has an amorphous structure, , A broad characteristic peak is observed.

  Note that a carbon material, a metal, and a metal oxide can be used as a mixture without being used alone. For example, the same type of material may be mixed together such as graphite and amorphous carbon, or different types of materials such as graphite and silicon may be mixed.

  As the binder for the negative electrode, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene, polypropylene, polyethylene, Polyimide, polyamide imide, or the like can be used. The amount of the binder for the negative electrode to be used is 0.5 to 25 parts by mass with respect to 100 parts by mass of the negative electrode active material from the viewpoint of “sufficient binding force” and “high energy” in a trade-off relationship. Is preferred.

  As the negative electrode current collector, aluminum, nickel, stainless steel, chromium, copper, silver, and alloys thereof are preferable from the viewpoint of electrochemical stability. Examples of the shape include a foil, a flat plate, and a mesh.

<Positive electrode>
The positive electrode has a positive electrode current collector formed of a metal foil and a positive electrode active material applied to both surfaces of the positive electrode current collector. The positive electrode active material is bound by a positive electrode binder so as to cover the positive electrode current collector. The positive electrode current collector is formed to have an extension connected to the positive electrode terminal, and the extension is not coated with the positive electrode active material.

As the positive electrode active material, a layered structure such as LiMnO ₂ , LixMn ₂ O ₄ (0 <x <2), Li ₂ MnO ₃ , Li _x Mn _1.5 Ni _0.5 O ₄ (0 <x <2) is used. Lithium manganate having a spinel structure, lithium manganate having a spinel structure, LiCoO ₂ , LiNiO _2, or a material obtained by replacing a part of these transition metals with another metal, such as LiNi _1/3 Co _1/3 Mn _1/3 O ₂ Lithium transition metal oxides in which the specific transition metal does not exceed 50%, those having an excess of Li over the stoichiometric composition in these lithium transition metal oxides, those having an olivine structure such as LiFePO ₄ , and the like. Can be Further, these metal oxides were partially substituted with Al, Fe, P, Ti, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, and the like. Materials can also be used. In _{particular, Li α Ni β Co γ Al} δ O 2 (≦ 1 ≦ α 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2) or _{Li α Ni β Co γ Mn δ} O 2 (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.6, γ ≦ 0.2). As the positive electrode active material, one kind can be used alone, or two or more kinds can be used in combination.

  As the binder for the positive electrode, the same binder as the binder for the negative electrode can be used. The amount of the binder for the positive electrode to be used is preferably 2 to 15 parts by mass with respect to 100 parts by mass of the positive electrode active material from the viewpoint of “sufficient binding force” and “high energy” in a trade-off relationship. .

  As the positive electrode current collector 24, for example, aluminum, nickel, silver, or an alloy thereof can be used. Examples of the shape of the positive electrode current collector include a foil, a flat plate, and a mesh. An aluminum foil can be suitably used as the positive electrode current collector.

  A conductive auxiliary material may be added to the coating layer of the positive electrode active material for the purpose of reducing impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.

<Electrolyte>
As the electrolytic solution used in the present embodiment, a non-aqueous electrolytic solution containing a lithium salt (supporting salt) and a non-aqueous solvent that dissolves the supporting salt can be used.

  As the non-aqueous solvent, an aprotic organic solvent such as a carbonic acid ester (chain or cyclic carbonate), a carboxylic acid ester (chain or cyclic carboxylic acid ester), and a phosphoric acid ester can be used.

  Examples of the carbonate solvent include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC); dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate. (EMC), chain carbonates such as dipropyl carbonate (DPC); and propylene carbonate derivatives.

  Examples of the carboxylic acid ester solvent include aliphatic carboxylic acid esters such as methyl formate, methyl acetate, and ethyl propionate; and lactones such as γ-butyrolactone.

  Among these, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), dipropyl carbonate Carbonates (cyclic or linear carbonates) such as (DPC) are preferred.

  Examples of the phosphate include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, trioctyl phosphate, triphenyl phosphate and the like.

  In addition, examples of the solvent that can be contained in the nonaqueous electrolyte include, for example, ethylene sulfite (ES), propane sultone (PS), butane sultone (BS), dioxathiolane-2,2-dioxide (DD), and sulfolene. , 3-methylsulfolene, sulfolane (SL), succinic anhydride (SUCAH), propionic anhydride, acetic anhydride, maleic anhydride, diallyl carbonate (DAC), dimethyl 2,5-dioxahexanoate, 2,5 -Dimethyl dioxahexanoate, furan, 2,5-dimethylfuran, diphenyl disulfide (DPS), dimethoxyethane (DME), dimethoxymethane (DMM), diethoxyethane (DEE), ethoxymethoxyethane, chloroethylene carbonate , Dimethyl ether, methyl ether Ether, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, diethyl ether, phenyl methyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), tetrahydropyran (THP), 1,4-dioxane (DIOX), 1,3-dioxolane (DOL), methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl difluoroacetate, methyl propionate, ethyl propionate, propyl propionate, methyl formate , Ethyl formate, ethyl butyrate, isopropyl butyrate, methyl isobutyrate, methyl cyanoacetate, vinyl acetate, diphenyl Disulfide, dimethyl sulfide, diethyl sulfide, adiponitrile, valeronitrile, glutaronitrile, malononitrile, succinonitrile, pimeronitrile, suberonitrile, isobutyronitrile, biphenyl, thiophene, methyl ethyl ketone, fluorobenzene, hexafluorobenzene, carbonate electrolyte, glyme , Ether, acetonitrile, propionnitrile, γ-butyrolactone, γ-valerolactone, dimethylsulfoxide (DMSO) ionic liquid, phosphazene, methyl formate, methyl acetate, aliphatic carboxylic acid esters such as ethyl propionate, or compounds thereof In which some of the hydrogen atoms have been replaced by fluorine atoms.

As the supporting salt in the present embodiment, LiPF ₆ , LiAsF ₆ , LiAlCl ₄ , LiClO ₄ , LiBF ₄ , LiSbF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiN ( A lithium salt such as CF ₃ SO ₂ ) ₂ which can be used for a normal lithium ion battery can be used. As the supporting salt, one kind can be used alone, or two or more kinds can be used in combination.

  The non-aqueous solvents can be used alone or in combination of two or more.

<Outer body>
The exterior body can be appropriately selected as long as it is stable in the electrolytic solution and has a sufficient water vapor barrier property. For example, in the case of a laminate type secondary battery, it is preferable to use a laminate film of aluminum and resin as the outer package. The exterior body may be configured by a single member, or may be configured by combining a plurality of members.

  The battery element of the present invention is not limited to the above-described battery element of the lithium ion secondary battery, and the present invention is applicable to any battery. However, the problem of heat radiation often becomes a problem in a battery with a high capacity, and thus the present invention is preferably applied to a battery with a high capacity, particularly a lithium ion secondary battery.

As described above, the battery 1 according to one embodiment of the present invention includes:
A battery element 10 to which a positive terminal 11 and a negative terminal 12 are connected;
A redox shuttle cell (inter-terminal cell) 15 connected in parallel between the positive terminal 11 and the negative terminal 12,
Has,
The redox shuttle cell 15 includes a container 16 in which a redox shuttle agent that causes an oxidation-reduction reaction at a specific potential or higher is enclosed,
At least one first electrode 17a connected to the positive electrode terminal 11 and at least one second electrode 17b connected to the negative electrode terminal 12, at least a part of which is arranged inside the container 16,
Having.

  The battery 1 preferably further includes an element 21 connected in series to the redox shuttle cell 15 and having a non-linear current-voltage characteristic.

  The redox shuttle cell 15 has a pair of first electrodes 17a and second electrodes 17b at least partially opposed to each other inside the container 16, and has a heat-shrinkable or It is preferable that an insulating member 19 having heat melting property is arranged.

  Hereinafter, one embodiment of the method for producing a battery of the present invention will be described.

One mode of a battery manufacturing method is as follows.
Connecting the positive terminal 11 and the negative terminal 12 to the battery element 10;
A container 16 in which a redox shuttle agent that causes an oxidation-reduction reaction at a specific potential or higher is enclosed, and a redox shuttle cell electrode (at least a part of which is disposed inside the container 16 and connected to the positive electrode terminal 11 and the negative electrode terminal 12, respectively) Producing a redox shuttle cell (cell between terminals) 15 having at least one first electrode and at least one second electrode 17;
Connecting a redox shuttle cell (cell between terminals) 15 between the positive electrode terminal 11 and the negative electrode terminal 12 in parallel;
Having.

  In the above-described manufacturing method, it is preferable that the method further includes a step of connecting an element 20 having a non-linear current-voltage characteristic to the redox shuttle cell 15 in series.

  Further, the step of manufacturing the redox shuttle cell 15 can include a step of enclosing the redox shuttle agent inside the container 16 with at least a part of the pair of redox shuttle cell electrodes 17 arranged inside the container 16. . In this case, the step of fabricating the redox shuttle cell 15 is such that at least a part of the pair of redox shuttle cell electrodes 17 is disposed inside the container 16 so as to face each other, and between the pair of redox shuttle cell electrodes 17, heat shrinkage or thermal contraction occurs. It is preferable to include a step of arranging the insulating member 19 having fusibility.

  The battery according to the invention can be used, for example, in any industrial field that requires a power supply, and in the fields of transport, storage and supply of electrical energy. Specifically, power supplies for mobile devices such as mobile phones and notebook computers; power supplies for moving and transporting media such as trains, satellites, and submarines, including electric vehicles such as electric vehicles, hybrid cars, electric motorcycles, and electric assist bicycles. A backup power source such as a UPS; a power storage facility for storing power generated by solar power generation, wind power generation, or the like;

  FIGS. 9 and 10 are schematic diagrams of an electric vehicle 200 and a power storage facility 300, respectively, as examples of the various devices and the power storage facility described above. Electric vehicle 200 and power storage facility 300 have assembled batteries 210 and 310, respectively. The assembled batteries 210 and 310 are configured such that a plurality of the above-described batteries 1 are connected in series and in parallel to satisfy required capacity and voltage.

DESCRIPTION OF SYMBOLS 1 Battery 10 Battery element 11 Positive electrode terminal 12 Negative electrode terminal 13 Outer body 15 Redox shuttle cell 16 Container 17 Redox shuttle cell electrode 19 Insulating member 20 Resistance component 21 Element (having non-linear current-voltage characteristics) 200 Electric vehicle 210, 310 Battery pack 300 power storage equipment

Claims (10)

A battery element to which the positive terminal and the negative terminal are connected,
An inter-terminal cell connected in parallel between the positive terminal and the negative terminal,
An element having a non-linear current-voltage characteristic, connected in series to the inter-terminal cell,
Has,
The inter-terminal cell, a container in which a redox shuttle agent that causes a redox reaction is enclosed,
At least a part disposed inside the container, having at least one first electrode connected to the positive electrode terminal and at least one second electrode connected to the negative electrode terminal,
Select the operating potential of the operating voltage and the element of the redox shuttle agent is the terminal between cells causing oxidation-reduction reaction, said a potential lower than the maximum potential of the positive electrode terminal, and, depending on the maximum potential of the positive electrode terminal Batteries.   The battery according to claim 1, wherein the element is a diode.   At least a part of the first electrode and the second electrode are opposed to each other inside the container, and an insulating member having a heat-shrinking property or a heat-fusing property is arranged between the first electrode and the second electrode. The battery according to claim 1, wherein the battery is formed. The terminal Mase Le A battery according to claims 1 having an electrical resistance component in any one of 3 between the negative terminal and the positive terminal.   5. The battery pack according to claim 1, further comprising an exterior body for enclosing the battery element in a state where the positive electrode terminal and the negative electrode terminal are pulled out, wherein the inside of the container is isolated from the inside of the exterior body. The battery according to 1.   An electric vehicle having the battery according to claim 1.   Power storage equipment comprising the battery according to claim 1. Connecting a positive terminal and a negative terminal to the battery element;
A container in which a redox shuttle agent that causes an oxidation-reduction reaction is enclosed, and at least a part disposed inside the container, at least one first electrode connected to the positive electrode terminal and at least one connected to the negative electrode terminal Producing an inter-terminal cell having one second electrode;
A step of serially connecting an element having a non-linear current-voltage characteristic to the inter-terminal cell,
A step of connecting the inter-terminal cell and the element connected in series between the positive terminal and the negative terminal in parallel,
Has,
Operating potential of operating potential and said element of said terminal between cells the redox shuttle agent cause oxidation-reduction reaction, such that the potential lower than the maximum potential of the positive electrode terminal, is selected according to the maximum potential of the positive electrode terminal Battery manufacturing method.   9. The step of fabricating the inter-terminal cell includes a step of enclosing the redox shuttle agent in the container with at least a part of the first electrode and the second electrode arranged in the container. 3. The method for producing a battery according to item 1.   The step of fabricating the inter-terminal cell includes disposing at least a part of the first electrode and the second electrode in the container so as to face each other; The method for manufacturing a battery according to claim 8, further comprising a step of arranging an insulating member having heat melting property.

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