JP2013168351A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack which includes a magnesium ion secondary battery capable of charging/discharging regardless the type of an electrolyte and improved in cycle characteristic and charge/discharge efficiency.SOLUTION: A battery pack includes a housing case, a magnesium ion secondary battery including a positive electrode terminal and a negative electrode terminal, and a protection circuit including an over-charge protection function and an over-discharge protection function, and the magnesium ion secondary battery and the protection circuit are stored in the housing case. The magnesium ion secondary battery includes a positive electrode plate, a negative electrode plate and an electrolyte, and the negative electrode plate includes a material for the negative electrode plate of the magnesium ion secondary battery. The material for the negative electrode plate of the magnesium ion secondary battery includes magnesium metal and an allotrope of carbon, and the magnesium metal and the allotrope of carbon are in contact with each other in part.

Description

  The present invention relates to a battery pack, and more particularly to a battery pack including a magnesium ion secondary battery.

  In recent years, environmental problems such as global warming caused by an increase in carbon dioxide have become serious, and countermeasures are being promoted worldwide. In particular, active research and development on secondary batteries represented by lithium ion secondary batteries and the like as a clean energy source with a low environmental load are being promoted.

  Furthermore, recently, secondary batteries having higher energy density than lithium metal have been sought, and magnesium metal having higher energy density than lithium metal, resource-rich and superior safety is used. Various proposals for magnesium ion secondary batteries have been made.

  In a magnesium ion secondary battery, it is simple and preferable to use a negative electrode plate material containing magnesium metal in the negative electrode plate, but the magnesium metal is derived from moisture contained in an electrolyte or the like using air or an aqueous solvent. It is known to produce a magnesium oxide film on its surface. Since this magnesium oxide film is a passive film, the presence of the magnesium oxide film formed on the surface of the magnesium metal causes the migration of magnesium ions from the magnesium metal to the electrolyte and the magnesium ions from the electrolyte to the magnesium metal. Is hindered, and the charge / discharge efficiency and cycle characteristics are significantly reduced. In some cases, charging and discharging cannot be performed.

  At present, measures against the above problems have been taken with electrolytes. For example, Grignard reagent (RMgX: R is an alkyl group or aryl group, Mg is magnesium, and X is any of iodine, bromine, and chlorine). It is known that the formation of a magnesium oxide film on the surface of magnesium metal can be suppressed by using an ether solution of

  In addition to this, for example, in Patent Document 1, magnesium electrolyte, alkyl trifluoromethanesulfonate, quaternary ammonium salt and / or 1, as an electrolyte capable of sufficiently extracting the excellent characteristics of magnesium metal. An electrolyte in which a 3-alkylmethylimidazolium salt is added to an ether organic solvent and magnesium ions are dissolved in the ether organic solvent has been proposed.

International Publication No. 2009/148112

  However, even when the electrolyte proposed above is used, the negative electrode plate containing magnesium metal known to date does not have sufficient cycle characteristics and charging / discharging efficiency, and is still unsatisfactory. There is room for improvement. In addition, there is a high market demand for magnesium ion secondary batteries that can be charged and discharged without being limited to the type of electrolyte, and improvements in this respect are also desired.

  The present invention has been made in view of such circumstances, and is capable of charging / discharging without being limited to the type of electrolyte, and for a negative electrode plate of a magnesium ion secondary battery that improves cycle characteristics and charging / discharging efficiency. The main object is to provide a material, a negative electrode plate for a magnesium ion secondary battery, a magnesium ion secondary battery, and a battery pack.

  The present invention for solving the above problems is a material for a negative electrode plate of a magnesium ion secondary battery, comprising magnesium metal and an allotrope of carbon, and the magnesium metal and the allotrope of carbon partially in contact with each other It is characterized by that.

  Further, the present invention for solving the above problems is a negative electrode plate for a magnesium ion secondary battery, wherein the negative electrode plate for a magnesium ion secondary battery includes a material for a negative electrode plate of a magnesium ion secondary battery, The negative electrode plate material of a magnesium ion secondary battery includes a magnesium metal and an allotrope of carbon, and the magnesium metal and the allotrope of carbon are in contact with each other. It is characterized by being.

  Moreover, this invention for solving the said subject is a magnesium ion secondary battery containing a positive electrode plate, a negative electrode plate, and electrolyte, Comprising: The said negative electrode plate uses the material for negative electrode plates of a magnesium ion secondary battery. A negative electrode of a magnesium ion secondary battery, wherein the negative electrode plate material of the magnesium ion secondary battery includes an allotrope of magnesium metal and carbon, and the magnesium metal and the allotrope of carbon are in contact with each other It is a board material.

  Further, the present invention for solving the above problems includes a storage case, a magnesium ion secondary battery including a positive electrode terminal and a negative electrode terminal, and a protection circuit including an overcharge protection function and an overdischarge protection function. A battery pack configured by housing a magnesium ion secondary battery and the protection circuit in a case, wherein the magnesium ion secondary battery includes a positive electrode plate, a negative electrode plate, and an electrolyte. A negative electrode plate material for a magnesium ion secondary battery, the negative electrode plate material for the magnesium ion secondary battery includes an allotrope of magnesium metal and carbon, and the magnesium metal and the allotrope of carbon are in part. It is a material for a negative electrode plate of a magnesium ion secondary battery that is in contact.

  According to the negative electrode plate material of the magnesium ion secondary battery of the present invention, it is possible to charge and discharge without being limited to the type of electrolyte, and to provide a magnesium ion secondary battery that improves cycle characteristics and charge and discharge efficiency. be able to. Moreover, according to the negative electrode plate for magnesium ion secondary batteries, the magnesium ion secondary battery, and the battery pack using this negative electrode plate material, there exists an effect of said negative electrode plate material.

It is a figure which shows an example of the material for negative electrode plates of this invention. It is a figure which shows an example of the material for negative electrode plates of this invention. It is a figure which shows an example of the material for negative electrode plates of this invention. It is a figure which shows an example of the material for negative electrode plates of this invention. It is sectional drawing which shows an example of the negative electrode plate for magnesium ion secondary batteries of this invention. It is sectional drawing which shows an example of the negative electrode plate for magnesium ion secondary batteries of this invention. It is the schematic which shows an example of the magnesium ion secondary battery of this invention. It is a sectional exploded view showing an example of a battery pack of the present invention.

  Hereinafter, the negative electrode plate material of the magnesium ion secondary battery of the present invention will be specifically described with reference to the drawings.

<Material for negative electrode plate of magnesium ion secondary battery>
As shown in FIGS. 1 to 4, the material for a negative electrode plate of a magnesium ion secondary battery of the present invention includes magnesium metal and an allotrope of carbon, and the magnesium metal and the allotrope of carbon partially contact each other. ing. Hereinafter, the negative electrode plate material of the magnesium ion secondary battery of the present invention may be referred to as a negative electrode plate material.

  In the present invention, as a material for the negative electrode plate, charging / discharging has been conventionally performed by using a material that includes magnesium metal and an allotrope of carbon and has a form in which the magnesium metal and the allotrope of carbon are in contact with each other. Even a liquid electrolyte using an aqueous solvent, which has been impossible, can be charged and discharged. In addition, when an electrolyte capable of charging and discharging a magnesium ion secondary battery, for example, an ether solution of a Grignard reagent or the like is used as the electrolyte, dramatic improvement in cycle characteristics and charging / discharging efficiency is expected. By using the negative electrode plate material of the present invention, the mechanism that exerts these effects is not clear at present, but because the magnesium metal is in contact with the carbon allotrope, an oxide film is not formed on the surface, Or it becomes difficult to form, and it can be considered that the above-mentioned excellent effect is exhibited. Further, in this case, it is considered that the magnesium ions move along the electrolyte, the inside of the carbon allotrope, the contact interface, the route that passes through the magnesium metal in this order, or the route that passes in the reverse order. . In any case, the superiority of the negative electrode plate material of the present invention is apparent from the results of Examples and Comparative Examples described later.

  The negative electrode plate material of the present invention only needs to satisfy the condition that it contains magnesium metal and an allotrope of carbon, and the magnesium metal and the allotrope of carbon are in contact with each other. For example, the negative electrode plate material of the present invention can include the following four forms.

(First form)
The negative electrode plate material according to the first embodiment has a configuration in which both magnesium metal and carbon allotrope are in particulate form, and the particulate magnesium metal 1 and carbon allotrope 2 are in contact with each other ( (See FIG. 1).

  In the negative electrode plate material of the present invention, when the magnesium metal and the carbon allotrope are in contact with each other, the following modes can be cited. One embodiment includes an embodiment in which the magnesium metal and the carbon allotrope are directly fixed, whereby the magnesium metal and the carbon allotrope are partially in contact. This aspect can be realized, for example, by fusing magnesium metal and carbon allotrope. As another embodiment, an embodiment in which the magnesium metal and the carbon allotrope are fixed with a binder or the like so that the magnesium metal and the carbon allotrope partially contact each other can be exemplified. Examples of the binder include organic polymer compounds such as polyvinylidene fluoride, cellulose polymer compounds such as methyl cellulose and ethyl cellulose, and polyimide polymer compounds.

  The magnesium metal constituting the negative electrode plate material may be a magnesium metal alone or a magnesium alloy. Magnesium metal alone is not limited to a purity of 100%, but also includes those containing inevitable impurities. The magnesium alloy may be any material that contains magnesium metal as a main component. For example, an alloy of magnesium and aluminum, an alloy of magnesium and zinc, an alloy of magnesium, aluminum, and zinc, or another metal and magnesium metal. Can be mentioned. In the specification of the present application, the term “magnesium alloy” means that the magnesium metal is the main component and the magnesium metal and other elements are present in the same phase. There is no particular limitation on the content of magnesium metal as a main component contained in the magnesium alloy, but when the content of magnesium metal is less than 80% by mass, phases of other elements added exist independently. It becomes a trend. Therefore, considering this point, it is preferable that magnesium metal is contained in an amount of 80% by mass or more based on the total mass of the magnesium alloy. The same applies to the magnesium metal used in the negative electrode plate materials of the second to fourth embodiments described below.

  The shape of the magnesium metal in the first form is also not particularly limited, and for example, a scale shape, a flat shape, a spindle shape, or a spherical shape can be used. Further, there is no particular limitation on the particle diameter of the magnesium metal, and an arbitrary size can be appropriately selected in consideration of the thickness of the negative electrode plate formed using the negative electrode plate material. . In the present embodiment, an allotrope of carbon having an average particle diameter of about 0.1 μm to 100 μm can be preferably used.

  Although there is no particular limitation on the carbon allotrope that partially contacts with the magnesium metal, in the present invention, carbon having a graphene structure, for example, graphite such as natural graphite or artificial graphite, carbon nanotube, fullerene, or diamond having a graphene bond Like carbon can be preferably used. By using carbon having such a graphene structure, it is considered that magnesium ions and an electrolyte can smoothly pass through the carbon allotrope. More specifically, for example, when a liquid electrolyte using an aqueous solvent is used, the magnesium ion is considered to form a complex with the electrolyte and the aqueous solvent. It is considered that it can pass through the carbon allotrope and reach the electrode to exchange electrons.

In addition, carbon such as amorphous carbon, carbon black, carbon fiber, carbon nanofiber, etc. can be used as the carbon allotrope. Furthermore, carbon obtained by heating at a temperature higher than the temperature at which the organic polymer compound is thermally decomposed can also be used. The same applies to the carbon allotrope used in the negative electrode plate materials of the second to fourth embodiments described below. Hereinafter, allotropes of carbon are sometimes collectively referred to as carbon.

  The shape of carbon in the first form is also not particularly limited, and the same shape as that of the magnesium metal can be used. Also, the particle diameter of carbon is not particularly limited, and a carbon particle having an arbitrary size can be appropriately selected and used in consideration of the thickness of the negative electrode plate formed using the negative electrode plate material. In the present embodiment, carbon having an average particle diameter of about 0.1 to 50 μm can be preferably used.

  The negative electrode material of the first form is composed of at least one particulate magnesium metal and one particulate carbon. In the form shown in FIG. 1, the negative electrode plate material is composed of a plurality of particulate magnesium metals and a plurality of particulate carbon, and all the magnesium particles constituting the negative electrode plate material are: Although it is partly in contact with carbon, it is not limited to this configuration, and if at least part of magnesium metal in a plurality of particulate magnesium metals constituting the negative electrode plate material is in contact with carbon Good.

(Second form)
The negative electrode plate material of the second form is formed by coating at least part of the surface of the particulate magnesium metal with film-like carbon, or covering the surface with particulate carbon so that the magnesium metal and carbon are in contact with each other. It takes the composition which is. That is, the negative electrode plate material of the second embodiment is a negative electrode plate material having a core-shell structure. 2A, 2B, and 2C are cross-sectional views of a negative electrode plate material for explaining a core-shell structure.

  The film-like carbon may be fixed so as to cover the entire surface of the magnesium metal as shown in FIG. 2 (a), and is scattered on the surface of the magnesium metal as shown in FIG. 2 (b). It may be fixed to. Moreover, as shown in FIG.2 (c), it may take the aspect which replaces with film-form carbon, and a some particle form carbon adheres to at least one part of the surface of magnesium metal. In any embodiment, a part of the surface of the magnesium metal is in contact with carbon.

  The case where the magnesium metal and the carbon allotrope are in contact with each other includes the case where the entire surface of the magnesium metal is in contact with the carbon allotrope. For example, as shown in FIG. 2A, when the film-like carbon is fixed so as to cover the entire surface of the magnesium metal, that is, when the entire surface of the magnesium metal is in contact with the carbon allotrope. However, it can be said that magnesium metal and the carbon allotrope are in contact with each other. In addition, when covering the whole surface of magnesium metal with film-like carbon, it is preferable that this film-like carbon has a space | gap so that electrolyte can be passed. Whether or not the film-like carbon has voids can be confirmed by a scanning electron microscope (magnification: 10,000 to 50,000 times).

  In this case, when the film-like carbon covering the magnesium metal has a graphene structure such as graphite, it is considered that the electrolyte can pass between the layers. The carbon does not need to have voids.

  Whether or not carbon is contained in the negative electrode plate material of the second form is determined by elemental mapping indicated by nano-order elemental analysis using a transmission electron microscope, by scanning transmission electron microscopy, and by an EDX detector. Can be confirmed.

  The negative electrode plate material in the form of covering the surface of the magnesium metal with film-like carbon (see FIGS. 2A and 2B) is, for example, an organic material that becomes carbon by heating at a temperature equal to or higher than the thermal decomposition temperature. The polymer compound can be formed by dispersing or dissolving the polymer compound in a solvent, preparing a solution in which the polymer compound is mixed with magnesium metal, and heating the solution at a temperature equal to or higher than the thermal decomposition of the organic polymer compound. In addition to this, a carbon film can be formed on the surface of the magnesium metal by vapor deposition or aerosol deposition. Examples of the vapor deposition method include physical vapor deposition and chemical vapor deposition.

  As the organic polymer compound, it is preferable to select and use a transition metal compound having a heating weight reduction rate of less than 100% by weight at the thermal decomposition start temperature.

  On the other hand, the negative electrode plate material in which the surface of the magnesium metal is covered with particulate carbon (see FIG. 2C) is, for example, particulate particulate metal, particulate carbon, and binder in a solvent. A dispersed or dissolved solution can be prepared and formed by heating. Examples of the binder include organic polymer compounds such as polyvinylidene fluoride.

(Third form)
In the negative electrode plate material of the third embodiment, a carbon film is provided on a magnesium metal substrate 1, whereby the magnesium metal and carbon are in contact (see FIG. 3). According to the negative electrode plate material of the third aspect, the negative electrode plate material can be used as it is as the negative electrode plate.

  As the magnesium metal substrate 1, a magnesium metal foil or the like can be used. Although there is no limitation in particular about the thickness of the board | substrate 1 of a magnesium metal, it is preferable that it is 10-100 micrometers, and it is more preferable that it is 10-50 micrometers.

  The material for the negative electrode plate of the third form is prepared by, for example, preparing a solution in which the organic polymer compound described in the second form and a binder added as necessary are dispersed or dissolved in a solvent. After coating on a magnesium metal substrate, it can be formed by heating at a temperature above the temperature at which the organic polymer compound is thermally decomposed.

  In addition to this, a carbon film can be formed on the surface of the magnesium metal substrate by vapor deposition or aerosol deposition. As an example of the vapor deposition method, the method described in the second embodiment can be applied as it is.

  Although there is no limitation in particular about the thickness of the film | membrane of carbon, it is preferable that the thickness at the time of drying is about 0.1-5 micrometers.

(4th form)
The negative electrode plate material according to the fourth embodiment has a structure in which a plurality of particulate carbons 2 are provided on a magnesium metal substrate 1 so that the magnesium metal substrate 1 and the particulate carbon 2 are in contact with each other. (See FIG. 4). According to the negative electrode plate material of the fourth embodiment, the negative electrode plate material can be used as it is as the negative electrode plate, as in the third embodiment.

  The magnesium metal substrate 1 can be the same as that used in the third embodiment, and a description thereof is omitted here.

  As the particulate carbon, the particulate carbon described in the first embodiment can be used as it is, and the description thereof is omitted here.

  The negative electrode material of the fourth form is a coating liquid in which particulate carbon, for example, graphite particles, and a binder are dissolved or dispersed in a suitable solvent, and this is applied to the surface of a magnesium metal substrate. It can be obtained by drying. Examples of the binder include organic polymer compounds such as polyvinylidene fluoride.

  As described above, when magnesium metal is in contact with the carbon allotrope, an oxide film is not formed on the surface or is difficult to be formed, and thus the above-described excellent effects are exhibited. be able to. Further, in this case, it is considered that the magnesium ions move along the electrolyte, the inside of the carbon allotrope, the contact interface, the route that passes through the magnesium metal in this order, or the route that passes in the reverse order. . Therefore, in all the forms of the first to fourth forms, it is preferable that the area of the portion where the carbon is in contact with the surface area of the magnesium metal is large. Specifically, the area of the portion where the carbon is in contact with the surface area of the magnesium metal is preferably 10% or more, and particularly preferably 40% or more. In addition, the surface area of magnesium metal means the total area of the area of the part which is contacting carbon, and the area of the part which is contacting the electrolyte among all the surfaces of magnesium metal.

  Various methods can be employed as a method for increasing the contact area of carbon. For example, when using particulate carbon, by contacting metal magnesium and carbon, pressing or the like is performed. The contact area can be increased. Moreover, when using film-like carbon, the contact area can be increased by increasing the covering area. The contact area can be confirmed with a scanning electron microscope.

  As described above, the magnesium metal, carbon, which is an essential component, and the binder, which is an optional component, have been described as the negative electrode material. However, the negative electrode material of the present invention includes, for example, a conductive polymer and other metals. The material, a conductive material such as a conductive ceramic, or a modifying material such as a catalyst may be included.

<Negative electrode for magnesium ion secondary battery>
The negative electrode plate for a magnesium ion secondary battery is a negative electrode plate using the negative electrode plate material for a magnesium ion secondary battery described above. In this invention, it takes the following forms according to the negative electrode material of the 1st-4th form demonstrated above. Hereinafter, the negative electrode plate for a magnesium ion secondary battery of the present invention may be simply referred to as the negative electrode plate of the present invention.

  As shown in FIGS. 5 and 6, the first form of the negative electrode plate 30 of the present invention is a form in which the negative plate material of the present invention is provided on the support substrate 20. Specifically, the negative electrode plate material of the first form or the second negative electrode plate material is provided on the support substrate 20. FIG. 5 is a cross-sectional view showing a negative electrode plate in which the negative electrode plate material 10 of the first embodiment is provided on the support substrate 20, and FIG. 6 shows the second embodiment of the second embodiment on the support substrate 20. It is sectional drawing which shows the negative electrode plate in which the negative electrode plate material 10 was provided.

  Examples of the support substrate 20 for supporting the negative electrode plate material of the first and second embodiments include an aluminum substrate, a nickel substrate, a magnesium substrate, a titanium substrate, a copper substrate, and a carbon plate. .

  Although there is no limitation in particular about the thickness of the support substrate 20, it is preferable that it is 10-100 micrometers, and it is more preferable that it is 10-50 micrometers.

  The negative electrode plate of the form shown in FIGS. 5 and 6 is prepared by preparing a coating solution in which the negative electrode plate material 10 of the present invention and a binder added as necessary are dissolved in an appropriate solvent, and this is used as a support substrate. It can be formed by coating and drying on 20.

  In the above, the negative electrode plate material of the first form and the second form is supported using the support substrate 20. For example, the negative plate material of the first form and the negative plate of the second form are supported. By pressing the material, the negative electrode plate material of the first form and the second form can be given a certain support. In this case, the support substrate 20 shown in FIG. 5 and FIG. 6 is not necessary, and the negative plate material pressed in the first and second embodiments can be used as it is as the negative plate.

  As a 2nd form of the negative electrode plate of this invention, on the negative electrode plate material of the 3rd form of this invention demonstrated above, the negative electrode plate material of the 4th form, ie, the magnesium metal board | substrate 1, The negative electrode plate material 10 provided with carbon 2 is used as the negative electrode plate 30 as it is (see FIGS. 3 and 4). In this embodiment, the magnesium metal substrate also has a function as a support.

  In addition, the negative electrode plate for a magnesium ion secondary battery in the present invention can take various modifications other than the configuration exemplified above. As a negative electrode plate of a deformation | transformation aspect, the separator integrated negative electrode plate can be mentioned, for example. As the separator-integrated negative electrode plate, in a configuration in which a carbon allotrope, for example, a carbon film or a plurality of carbon particles is provided on a magnesium metal substrate, a separator is provided on the carbon allotrope. And so on.

  In addition, a carbon allotrope such as a carbon film or a plurality of carbon particles is provided on the magnesium metal substrate and the separator. In the magnesium ion secondary battery, the magnesium metal substrate and the separator are provided on the separator. When the carbon allotrope is partially in contact, for example, when the magnesium metal substrate is in contact with the carbon coating or a plurality of carbon particles provided on the separator. In other words, it can be said that the negative electrode plate of the present invention, that is, the separator-integrated negative electrode plate of the above-described modification exists in the magnesium ion secondary battery.

<Magnesium ion secondary battery>
Next, the magnesium ion secondary battery of the present invention will be described with reference to FIG. FIG. 7 is a schematic view showing an example of the magnesium ion secondary battery 100 of the present invention. As shown in FIG. 7, the magnesium ion secondary battery of the present invention includes a positive electrode plate 40 and a negative electrode plate 30 combined with the positive electrode plate 40, and these are accommodated in a container configured with an exterior 81. In addition, the container is hermetically sealed with the electrolyte 90 filled therein.

  Here, the magnesium ion secondary battery 100 of the present invention is characterized in that the negative electrode plate 30 is the negative electrode plate of the present invention described above. Specifically, the negative electrode plate using the negative electrode plate material 10 of the present invention in which magnesium metal and carbon are partially in contact is an essential component. The magnesium ion secondary battery 100 of the present invention is not particularly limited with respect to other requirements as long as it has this requirement, and a conventionally known positive electrode plate, electrolyte, and container are appropriately selected in the field of magnesium ion secondary batteries. The present invention is not limited to the form shown in FIG. As the negative electrode plate, the negative electrode plate of the present invention described above can be used as it is, and description thereof is omitted here.

  The positive electrode plate 40 is usually composed of a positive electrode substrate and a positive electrode material provided on the positive electrode substrate. Examples of the positive electrode substrate include an aluminum plate, a copper plate, a titanium plate, a nickel plate, and a stainless plate having a thickness of about 10 to 100 μm.

The positive electrode material only needs to be able to reversibly insert and desorb magnesium ions. For example, such a positive electrode material includes graphite fluoride ((CF) _n ), manganese dioxide (MnO ₂ ). And manganese oxide, and vanadium oxide such as divanadium pentoxide (V ₂ O ₅ ).

  The electrolyte 90 is not particularly limited, and an electrolytic solution using an aqueous solvent or an organic solvent, an ionic liquid, a solid electrolyte, a gel electrolyte, or the like can be used.

As an example of the electrolyte, known electrolytes capable of inserting and removing magnesium ions, for example, Grignard reagent (RMgX: R is an alkyl group or an aryl group, Mg is magnesium, X is iodine, bromine, And an ether solution of magnesium bis (trifluoromethanesulfone) imide (Mg (TFSI) ₂ ) in propylene carbonate or a dimethoxyethane solvent. According to the magnesium ion secondary battery 100 of the present invention, when these electrolytes are used, an improvement in charge / discharge efficiency and an improvement in cycle characteristics are expected as compared with the case where a conventionally known negative electrode plate is used. .

  In addition, according to the present invention, when a negative electrode plate of a conventional magnesium ion secondary battery is used, a liquid electrolyte using an aqueous solvent, for example, magnesium nitrate is used as a solvent such as water. Charging / discharging is possible even when a dissolved electrolyte, an electrolyte in which lithium nitrate is dissolved in a solvent such as water, or the like are used.

  As a structure of the magnesium ion battery manufactured using the positive electrode plate, the negative electrode plate 30 of the present invention, and the electrolyte 90, a conventionally known structure can be appropriately selected and used. For example, the structure which winds a positive electrode plate and a negative electrode plate in the shape of a spiral via the separator like the polyethylene-made porous film which is not shown in figure, and accommodates in a battery container is mentioned. As another aspect, a structure in which a positive electrode plate and a negative electrode plate cut into a predetermined shape are stacked and fixed via a separator, and this is housed in a battery container may be employed. In any structure, after the positive electrode plate and the negative electrode plate are stored in the battery container, the lead wire attached to the positive electrode plate is connected to the positive electrode terminal provided in the outer container, while the lead wire attached to the negative electrode plate Is connected to a negative electrode terminal provided in the exterior container, and the battery container is further filled with an electrolyte 90, and then sealed to produce a magnesium ion secondary battery. In addition, when using solid electrolyte, gel electrolyte, etc. as the electrolyte 90, a separator can be made unnecessary.

(Battery pack)
Next, a battery pack 200 configured using the magnesium ion secondary battery 100 of the present invention will be described with reference to FIG. FIG. 8 is a schematic exploded view showing an example of the battery pack 200 of the present invention.

  As shown in FIG. 8, the battery pack 200 includes a magnesium ion secondary battery 100 housed in a resin container 36 a, a resin container 36 b, and an end case 37. Further, a protective circuit board 34 for preventing overcharge and overdischarge between one end face of the magnesium ion secondary battery and a face including the positive electrode terminal 32 and the negative electrode terminal 33 and the end case 37. Is provided.

  The protection circuit board 34 includes an external connection connector 35. The external connection connector 35 is connected to an external connection window 38a provided in the resin container 36a and an external connection window 38b provided in the end case 37. Inserted and connected to external terminals. The protection circuit board 34 includes a charge / discharge safety circuit (not shown) for controlling charge / discharge, a wiring circuit for connecting the external connection terminal and the magnesium ion secondary battery 100, and the like.

  The battery pack 200 can appropriately select a configuration of a conventionally known battery pack except that the magnesium ion secondary battery 100 of the present invention is used. Although not shown, the battery pack 200 includes a positive electrode lead plate connected to the positive electrode terminal 32, a negative electrode lead plate connected to the negative electrode terminal 33, an insulator, and the like between the magnesium ion secondary ground 100 and the end case 37. It may be provided as appropriate.

  In addition, the magnesium ion secondary battery 100 of the present invention has a function of blocking the excessive current, monitoring the battery temperature, etc., in addition to the use mode for the battery pack, and the protection circuit includes the magnesium ion. You may use for the aspect attached to the secondary battery 100 integrally. In such an embodiment, the battery pack can be used as a magnesium ion secondary battery including a protection function and a protection circuit without constituting a battery pack, and is highly versatile. In addition, some aspects demonstrated above are only illustrations, and do not limit use of the negative electrode plate 30 of this invention, or the magnesium ion secondary battery 200 of this invention at all.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. Hereinafter, unless otherwise specified, parts or% is based on mass.

Example 1
Creation of positive electrode plate 1;
Manganese oxide (MnO ₂ ): 10 g, acetylene black: 1 g, polyvinylidene fluoride (PVDF) (manufactured by Kureha Co., Ltd., KF # 1100) 10% dissolved in n-methylpyrrolidone (NMP) solvent (manufactured by Mitsubishi Chemical Corporation) What was done: 10g was mixed, and it stirred for 5 minutes with the rotation speed of 4000 rpm with the Excel auto homogenizer (Nippon Seiki Seisakusho Co., Ltd.), and obtained the ink for positive electrode plates 1. FIG. This ink was applied on an aluminum substrate having a thickness of 15 μm with an applicator having a gap of 200 μm, dried at 150 ° C., and then pressed at 2 ton / cm to obtain positive electrode plate 1.

Creation of negative electrode plate 1;
Graphite particles (CGC50, Nippon Graphite Industries Co., Ltd. average particle size 5 μm): 10 g, PVDF (manufactured by Kureha Corporation, KF # 1100) in n-methylpyrrolidone (NMP) solvent (manufactured by Mitsubishi Chemical Corporation) 10% Dissolved: 10 g was mixed and stirred for 5 minutes at 4000 rpm with an Excel auto homogenizer (Nihon Seiki Seisakusho Co., Ltd.) to obtain ink for negative electrode plate 1. This ink was applied onto a magnesium alloy (containing 3% aluminum and 1% zinc) plate having a thickness of 45 μm with an applicator having a gap of 200 μm, and dried at 100 ° C. to obtain negative electrode plate 1.

Preparation of electrolyte 1;
Electrolyte 1 was prepared by dissolving magnesium nitrate hexahydrate in water to a concentration of 1 mol / l.

Creation of tripolar coin cell 1;
The tripolar coin cell 1 of Example 1 is assembled by using the positive electrode plate 1 prepared above as a working electrode, the negative electrode plate 1 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 1 prepared above as an electrolyte. It was.

(Example 2)
Creation of negative electrode plate 2;
The ink for negative electrode plate 1 is applied to a magnesium alloy (containing 3% aluminum and 1% zinc) plate having a thickness of 45 μm with an applicator having a gap of 200 μm, dried at 100 ° C., and then pressed at 2 ton / cm. Thus, the negative electrode plate 2 was obtained.

Preparation of electrolyte 2;
Electrolyte 2 was prepared by dissolving magnesium bis (trifluoromethanesulfone) imide (Mg (TFSI) ₂ ) in a propylene carbonate solvent so as to have a concentration of 0.5 mol / l.

Creation of tripolar coin cell 2;
Using the positive electrode plate 1 used in Example 1 as a working electrode, the negative electrode plate 2 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 2 prepared above as an electrolyte, the tripolar coin cell 2 of Example 2 Assembled.

(Example 3)
Preparation of electrolyte 3;
Electrolyte 3 was prepared by dissolving magnesium bis (trifluoromethanesulfone) imide (Mg (TFSI) ₂ ) in a dimethoxyethane solvent so as to have a concentration of 0.5 mol / l.

Creation of tripolar coin cell 3;
Using the positive electrode plate 1 used in Example 1 as a working electrode, the negative electrode plate 2 used in Example 2 as a counter electrode and a reference electrode plate, and the electrolyte 3 prepared above as an electrolyte, the tripolar type of Example 3 A coin cell 3 was assembled.

Example 4
Creation of negative electrode plate 3;
Magnesium metal particles (average particle size 15 μm): 5 g, graphite particles (CGC50, manufactured by Nippon Graphite Industries Co., Ltd. average particle size 5 μm): 5 g, 3% of methylcellulose dissolved in an aqueous solvent: 30 g are mixed, and Excel The mixture was stirred with an autohomogenizer (Nippon Seiki Seisakusho Co., Ltd.) at a rotational speed of 4000 rpm for 5 minutes to obtain an ink for negative electrode plate 3. This ink was applied onto a copper substrate having a thickness of 10 μm with an applicator having a gap of 100 μm, dried at 100 ° C., and then pressed at 2 ton / cm to obtain the negative electrode plate 3.

Preparation of electrolyte 4;
Electrolyte 4 was prepared by dissolving magnesium nitrate hexahydrate in an n-methylpyrrolidone (NMP) solvent so as to have a concentration of 1 mol / l.

Creation of tripolar coin cell 4;
Using the positive electrode plate 1 used in Example 1 as a working electrode, the negative electrode plate 3 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 4 prepared above as an electrolyte, the tripolar coin cell 4 of Example 4 Assembled.

(Example 5)
Creation of positive electrode plate 2;
Divanadium pentoxide (V ₂ O ₅ ): 10 g, acetylene black: 1 g, PVDF (manufactured by Kureha Co., Ltd., KF # 1100) was dissolved 10% in an n-methylpyrrolidone (NMP) solvent (manufactured by Mitsubishi Chemical Corporation). Things: 10 g was mixed and stirred for 5 minutes at 4000 rpm with an Excel Auto Homogenizer (Nippon Seiki Seisakusho Co., Ltd.) to obtain ink for positive electrode plate 2. This ink was applied on an aluminum substrate having a thickness of 15 μm with an applicator having a gap of 200 μm, dried at 150 ° C., and then pressed at 2 ton / cm to obtain a positive electrode plate 2.

Creation of tripolar coin cell 5;
Using the positive electrode plate 2 prepared above as the working electrode, the negative electrode plate 2 used in Example 2 as the counter electrode and reference electrode plate, and the electrolyte 3 prepared in Example 3 as the electrolyte, the tripolar type of Example 5 A coin cell 5 was assembled.

(Example 6)
Creation of negative electrode plate 4;
Graphite particles (CGC50, Nippon Graphite Industries Co., Ltd. average particle size 5 μm): 10 g, PVDF (manufactured by Kureha Co., Ltd., KF # 1100) in n-methylpyrrolidone (NMP) solvent (manufactured by Mitsubishi Chemical Corporation) 10% Dissolved: 10 g was mixed and stirred for 5 minutes at 4000 rpm with an Excel auto homogenizer (Nippon Seiki Seisakusho Co., Ltd.) to obtain ink for negative electrode plate 4. This ink was coated on a magnesium plate having a thickness of 45 μm (magnesium purity 99.9%, manufactured by Nippon Metal Co., Ltd.) with an applicator having a gap of 200 μm and dried at 100 ° C. to obtain a negative electrode plate 4. .

Preparation of electrolyte 5;
Electrolyte 5 was prepared by dissolving magnesium nitrate hexahydrate in a γ-butyrolactone solvent so as to have a concentration of 1 mol / l.

Creation of tripolar coin cell 6;
Using the positive electrode plate 2 used in Example 5 as the working electrode, the negative electrode plate 4 prepared above as the counter electrode and the reference electrode plate, and the electrolyte 5 prepared above as the electrolyte, the tripolar coin cell 6 of Example 6 Assembled.

(Example 7)
Creation of negative electrode plate 5;
Example 6 except that a 45 μm thick magnesium plate (magnesium purity 99.9%, manufactured by Nippon Metal Co., Ltd.) was changed to a 45 μm thick magnesium alloy plate (containing 4% iron, manufactured by Nippon Metal Co., Ltd.). The negative electrode plate 5 was obtained in the same manner as the negative electrode plate 4 used in the above.

Creation of tripolar coin cell 7;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 5 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 5 prepared in Example 6 as an electrolyte, the tripolar type of Example 7 A coin cell 7 was assembled.

(Example 8)
Creation of negative electrode plate 6;
Graphite particles (CPB, manufactured by Nippon Graphite Industries Co., Ltd., average particle size 10 μm): 10 g, PVDF (manufactured by Kureha Co., Ltd., KF # 1100) in n-methylpyrrolidone (NMP) solvent (manufactured by Mitsubishi Chemical Corporation) 10% Dissolved: 10 g was mixed and stirred for 5 minutes at 4000 rpm with an Excel auto homogenizer (Nihon Seiki Seisakusho Co., Ltd.) to obtain ink for negative electrode plate 6. This ink was applied onto a magnesium alloy (containing 3% aluminum and 1% zinc) plate having a thickness of 45 μm with an applicator having a gap of 200 μm, and dried at 100 ° C. to obtain a negative electrode plate 6.

Creation of tripolar coin cell 8;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 6 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 5 prepared in Example 6 as an electrolyte, the tripolar type of Example 8 A coin cell 8 was assembled.

Example 9
Creation of negative electrode plate 7;
Graphite particles (CPB, manufactured by Nippon Graphite Industries Co., Ltd., average particle size 10 μm): 10 g was changed to carbon fiber (VGCF, manufactured by Showa Denko Co., Ltd., fiber diameter 150 nm, fiber length 10-20 μm): 10 g, A negative electrode plate 7 was obtained in the same manner as in the preparation of the negative electrode plate 6 used in Example 8.

Creation of tripolar coin cell 9;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 7 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 5 prepared in Example 6 as an electrolyte, the tripolar type of Example 9 A coin cell 9 was assembled.

(Example 10)
Creation of negative electrode plate 8;
Graphite particles (CPB, Nippon Graphite Industries Co., Ltd. average particle size 10 μm): 10 g was used in Example 8 except that 10 g was changed to acetylene black (AB powder, manufactured by Denki Kagaku Kogyo Co., Ltd.): 10 g. A negative electrode plate 8 was obtained in the same manner as in the preparation of the negative electrode plate 6.

Creation of tripolar coin cell 10;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 8 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 5 prepared in Example 6 as an electrolyte, the tripolar type of Example 10 The coin cell 10 was assembled.

(Example 11)
Creation of negative electrode plate 9;
Graphite particles (CGC50, manufactured by Nippon Graphite Industries Co., Ltd., average particle size 5 μm): 10 g was changed to 10 g of graphite particles (CGB20, manufactured by Nippon Graphite Industries Co., Ltd.), and magnesium having a thickness of 45 μm (magnesium purity) The 99.9%, manufactured by Nippon Metal Co., Ltd. plate was changed to a 45 μm-thick magnesium alloy (containing 4% nickel, manufactured by Nippon Metal Co., Ltd.) plate of the negative electrode plate 4 used in Example 6. A negative electrode plate 9 was obtained in the same manner as in the preparation.

Preparation of electrolyte 6;
Electrolyte 6 was prepared by dissolving magnesium bis (trifluoromethanesulfone) imide (Mg (TFSI) ₂ ) in an ethylene glycol (EG) solvent so as to have a concentration of 0.25 mol / l.

Creation of tripolar coin cell 11;
Using the positive electrode plate 2 used in Example 5 as the working electrode, the negative electrode plate 9 prepared above as the counter electrode and the reference electrode plate, and the electrolyte 6 prepared above as the electrolyte, the tripolar coin cell 11 of Example 11 Assembled.

(Example 12)
Creation of negative electrode plate 10;
Graphite particles (CPB, Nippon Graphite Industries Co., Ltd. average particle diameter 10 μm): Example 8 except that 10 g was changed to graphite particles (CGB20, Nippon Graphite Industry Co., Ltd. average particle diameter 15 μm) 10 g. A negative electrode plate 10 was obtained in the same manner as the negative electrode plate 6 used.

Creation of tripolar coin cell 12;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 10 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 6 prepared in Example 11 as an electrolyte, the tripolar type of Example 12 A coin cell 12 was assembled.

(Example 13)
Creation of negative electrode plate 11;
Used in Example 8 except that the graphite particles (CGC50, manufactured by Nippon Graphite Industries Co., Ltd., average particle size 5 μm: 10 g were changed to 10 g of graphite particles (UTC16, manufactured by Nippon Graphite Industries Co., Ltd., average particle size 20 μm). The negative electrode plate 11 was obtained in the same manner as the preparation of the negative electrode plate 6.

Creation of tripolar coin cell 13;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 11 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 6 prepared in Example 11 as an electrolyte, the tripolar type of Example 13 A coin cell 13 was assembled.

(Example 14)
Creation of negative electrode plate 12;
Graphite particles (CGC50, manufactured by Nippon Graphite Industries Co., Ltd., average particle diameter 5 μm): 10 g was changed to 10 g of carbon fiber (VGCF, Showa Denko Co., Ltd., fiber diameter 150 nm, fiber length 10-20 μm), A negative electrode plate 12 was obtained in the same manner as the negative electrode plate 6 used in Example 8.

Creation of tripolar coin cell 14;
Using the positive electrode plate 2 used in Example 5 as a working electrode, the negative electrode plate 12 prepared above as a counter electrode and a reference electrode plate, and the electrolyte 6 prepared in Example 11 as an electrolyte, the tripolar type of Example 14 A coin cell 14 was assembled.

(Comparative Example 1)
Graphite particles (average particle size 5 μm): A negative electrode plate A was obtained in the same manner as the negative electrode plate 1 obtained in Example 1 except that 10 g was not added.

Creation of tripolar coin cell A;
A tripolar coin cell A of Comparative Example 1 was assembled in the same manner as in Example 1 except that the negative electrode plate A was used instead of the negative electrode plate 1.

(Comparative Example 2)
Graphite particles (average particle size 5 μm): Negative electrode plate B was obtained in the same manner as negative electrode plate 2 obtained in Example 2 except that 10 g was not added.

Creation of tripolar coin cell B;
A tripolar coin cell B of Comparative Example 2 was assembled in the same manner as Example 2 except that the negative electrode plate B was used instead of the negative electrode plate 2.

(Comparative Example 3)
Creation of tripolar coin cell C;
A tripolar coin cell C of Comparative Example 3 was assembled in the same manner as in Example 3 except that the negative electrode plate B was used instead of the negative electrode plate 2.

(Comparative Example 4)
Creation of tripolar coin cell D;
A tripolar coin cell D of Comparative Example 4 was assembled in the same manner as Example 5 except that the negative electrode plate B was used instead of the negative electrode plate 2.

  Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 5 and Comparative Example 4, respectively, have negative electrode plates of Examples having an allotrope of magnesium metal and carbon. Including the negative electrode plate material in which the magnesium metal and the carbon allotrope are partially in contact with each other, except that the negative electrode plate of the comparative example does not contain the carbon allotrope. It is common. In Examples 6 to 14, graphite having different crystallinity and carbon allotropes other than graphite were used.

Charge / discharge test;
A charge / discharge test was conducted using the tripolar coin cell of each example and each comparative example. The charge / discharge test was performed in the following voltage range, and it was confirmed whether charging / discharging was possible using the tripolar coin cell of each example and comparative example. Note that all currents were applied at 30 μA / cm ² . Specifically, as the first discharge test, the battery was discharged to the lower limit voltage of the following voltage range, and as the charge / discharge test of the second cycle, charging to the upper limit value of the following voltage range, Discharge was performed. For example, in the evaluation of Example 1 and Comparative Example 1, discharging was performed up to 0.5 V as the first discharge test, and charging up to 1.5 V and discharging up to 0.5 V were performed as the second cycle charge / discharge test. It was.

  Moreover, about Examples 2-14 and Comparative Examples 2-4, charge and discharge were further repeatedly performed in the following voltage range after that. In this repetition, the first discharge was the first discharge test, and the subsequent charge and discharge tests were the second cycle, and this was repeated up to the 20th cycle. For example, in Example 2 and Comparative Example 2, discharging was performed up to 0.4V as the first discharge test, charging up to 1.8V and discharging up to 0.4V were performed as the second cycle charging / discharging test. The charge / discharge test was repeated up to the 20th cycle.

Example 1 and Comparative Example 1 Voltage range 0.5V to 1.5V
Example 2, Comparative Example 2 ... Voltage range 0.4V to 1.8V
Example 3, Comparative Example 3... Voltage range 0.4V to 1.7V
Example 4 ... Voltage range 0.5V to 1.4V
Example 5, Comparative Example 4 Voltage range 0.4 V to 1.5 V
Example 6 to Example 14 Voltage range 0.3V to 1.8V

  In the tripolar coin cell of Example 1, charge / discharge of the second cycle could be performed, but in the tripolar coin cell of Comparative Example 1, charge / discharge of the second cycle could not be performed. The tripolar coin cell of Example 1 and Comparative Example 1 is a comparative example in which the negative electrode plate of the tripolar coin cell of Example 1 contains graphite particles and the graphite particles are in contact with the magnesium alloy plate. The only difference is that the negative electrode plate of No. 1 tripolar coin cell does not contain graphite particles.

  In the tripolar coin cell of Example 2, improvement in cycle characteristics was confirmed as compared with the tripolar coin cell of Comparative Example 2. Similarly, in the tripolar coin cell of Example 3, improvement in cycle characteristics was confirmed as compared with the tripolar coin cell of Comparative Example 3. The cycle characteristic here means the discharge capacity maintenance when the discharge capacity after the first discharge (mAhr / g) is divided by the discharge capacity after the predetermined cycle discharge (mAhr / g) and multiplied by 100. This is an evaluation based on the rate, and when the charge / discharge capacity retention rate in a predetermined cycle is compared, the higher the charge / discharge capacity retention rate, the better the cycle characteristics. In addition, evaluation of the cycle characteristics of Example 2 and Comparative Example 2 and evaluation of the cycle characteristics of Example 3 and Comparative Example 3 were evaluated based on the discharge capacity maintenance rate after the second cycle discharge. . The discharge capacity is a value calculated from this discharge curve by performing constant current discharge at a discharge rate of 1 C, taking the cell voltage (V) on the vertical axis and the discharge time (h) on the horizontal axis, creating a discharge curve. . Further, “1C” means a current value (current value that reaches a discharge end voltage) at which constant current discharge is performed using the above-described tripolar coin cell and discharge is completed in one hour. The tripolar coin cells of Examples 2 and 3 were able to be charged / discharged up to the 20th cycle, whereas the tripolar coin cells of Comparative Examples 2 and 3 could be charged / discharged after the 2nd cycle. could not.

  Further, the tripolar type of Example 4 using a negative electrode plate provided with a material for a negative electrode plate in which particulate magnesium metal and an allotrope of particulate carbon are in contact with each other on a copper foil as a support substrate. In the coin cell, it was confirmed that charging / discharging after the second cycle was possible. Specifically, charge / discharge was possible up to the 20th cycle.

  Further, in the tripolar coin cell of Example 5, the charge / discharge efficiency in the second cycle is about 80%, whereas in the tripolar coin cell of Comparative Example 4, the charge / discharge efficiency in the second cycle is 27%. The advantages of the negative electrode plate material of the present invention, the negative electrode plate using the negative electrode plate material, and the magnesium ion secondary battery were revealed. The charge / discharge efficiency (%) in the second cycle is a value calculated from {(charge capacity after charge in the second cycle) / (discharge capacity after discharge in the second cycle)] × 100. Higher values mean better battery characteristics. The tripolar coin cell of Example 5 was able to charge and discharge up to the 20th cycle, whereas the tripolar coin cell of Comparative Example 4 could not be charged and discharged after the 3rd cycle.

  In Examples 6 and 7, the same allotrope of carbon as the carbon allotrope used in Examples 1 to 5 is used, and the electrolyte and magnesium metal are different from those in Examples 1 to 5. Examples 8 to 14 are examples in which the carbon allotrope is different from Examples 1 to 5. In each embodiment, the magnesium metal material and the electrolyte are appropriately changed. When a charge / discharge test was performed in the above voltage range, in all of the tripolar coin cells of Examples 6 to 14, charge / discharge after the second cycle was possible.

  As is clear from the results of using the tripolar coin cells of Examples 6 to 14, when the magnesium metal and electrolyte used in Examples 1 to 5 are different, or other than the graphite used in Examples 1 to 5 Even in the case of using the carbon allotrope and graphite having different crystallinity from those used in Examples 1 to 5, good results could be obtained as in Examples 1 to 5. From this, it has become clear that the effect of the present application can be achieved with any carbon allotrope.

DESCRIPTION OF SYMBOLS 10 ... Material for negative electrode plates of a magnesium ion secondary battery 1 ... Magnesium metal 2 ... Carbon allotrope 20 ... Support substrate 30 ... Negative electrode plate 32 ... Positive electrode terminal 33 ... Negative electrode Terminal 34 ... Protection circuit board 35 ... External connection connector 36a, 36b ... Resin container 37 ... End case 38a, 38b ... External connection window 40 ... Positive electrode plate 81 ... Exterior 100 ... Magnesium ion secondary battery 200 ... Battery pack

Claims (1)

A storage case, a magnesium ion secondary battery including a positive electrode terminal and a negative electrode terminal, and a protection circuit including an overcharge protection function and an overdischarge protection function, and the magnesium ion secondary battery and the protection circuit are stored in the storage case A battery pack comprising:
The magnesium ion secondary battery includes a positive electrode plate, a negative electrode plate, and an electrolyte,
The negative electrode plate includes a negative electrode plate material for a magnesium ion secondary battery,
The material for a negative electrode plate of the magnesium ion secondary battery includes an allotrope of magnesium metal and carbon, and the magnesium metal and the allotrope of carbon are in partial contact with each other. A battery pack characterized by being a material.

Images