JP2009181931A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve battery characteristics in a battery wherein a plurality of positive electrode plates and negative electrode plates are alternately stacked by interposing separators. <P>SOLUTION: In the battery 100 wherein a plurality of positive electrode members 11 made of a positive electrode active material and a collector and a plurality of negative electrode members 12 made of a negative electrode active material and a collector are alternately stacked by interposing separator members 13, the plurality of positive electrode members 11 are stacked so as to make respective mass of the positive electrode members 11 large along a predetermined laminating direction, and the plurality of negative electrode members 12 are stacked so as to make respective mass of the negative electrode members 12 large along the predetermined laminating direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention generally relates to a battery, and more particularly to a battery having a plurality of positive electrode members and negative electrode members stacked alternately between separators.

  In recent years, batteries, particularly secondary batteries, have been used as power sources for portable electronic devices such as mobile phones and portable personal computers. As an example of a secondary battery, a lithium ion secondary battery is known to have a relatively large energy density.

For example, Japanese Patent Laying-Open No. 2005-116482 (Patent Document 1) describes a configuration of a thin battery as a lithium ion secondary battery. In this thin battery, a positive electrode terminal in which a power generation element having a positive electrode plate and a negative electrode plate alternately stacked between separators is accommodated in an exterior member and sealed and connected to the power generation element via a plurality of current collectors And the negative electrode terminal is led out from the outer peripheral edge of the exterior member. In such a stacked secondary battery, a plurality of positive plates and negative plates are alternately stacked in the exterior member with separators interposed therebetween.
JP-A-2005-116482

  By the way, there are variations in the mass of each of the stacked positive and negative electrode plates due to manufacturing tolerances. For example, when an electrode plate is manufactured by a coating method, the positive electrode plate is configured by forming the positive electrode active material on the surface of the current collector, and the negative electrode plate is formed by forming the negative electrode active material on the surface of the current collector. It is composed by doing. The variation in the mass of the current collector is sufficiently small compared to the variation in the mass of the positive electrode active material layer or the negative electrode active material layer formed on the surface of the current collector. , Depending on variations in mass of the positive electrode active material layer or the negative electrode active material layer formed on the surface of the current collector.

  If there are variations in the mass of each of the stacked positive electrode plates and negative electrode plates, for example, as the combination of the opposing positive electrode plate and negative electrode plate, the heaviest positive electrode plate and heaviest material within the manufacturing tolerance of mass Combinations such as a negative electrode plate, the lightest positive electrode plate and the lightest negative electrode plate, the heaviest positive electrode plate and the lightest negative electrode plate, the lightest positive electrode plate and the heaviest negative electrode plate, etc. are conceivable. At this time, since the variation in the mass of the current collector is sufficiently small, the mass ratio of the negative electrode active material layer to the positive electrode active material layer formed on each opposed surface varies between each pair of the positive electrode plate and the negative electrode plate facing each other. become.

  The charge / discharge reaction is performed on the opposing surfaces of the plurality of stacked positive and negative electrode plates. According to the inventor's knowledge, in a battery in which the mass ratio of the negative electrode active material layer to the positive electrode active material layer formed on each facing surface varies, battery characteristics such as capacity retention rate (cycle life) are deteriorated. There is.

  Accordingly, an object of the present invention is to improve battery characteristics in a battery in which a plurality of positive plates and negative plates are alternately stacked with separators interposed therebetween.

  In the battery according to the present invention, a plurality of positive electrode members made of a positive electrode active material and a current collector and a plurality of negative electrode members made of a negative electrode active material and a current collector are alternately stacked with a separator member interposed therebetween. In the battery, the plurality of positive electrode members are stacked so that the mass of each of the positive electrode members is increased along a predetermined stacking direction, and the plurality of negative electrode members are each of the negative electrode members along the predetermined stacking direction. It is laminated so that the mass of

  In the battery of the present invention, the plurality of positive electrode members are stacked so that the mass of each of the positive electrode members is increased along a predetermined stacking direction, and the plurality of negative electrode members are formed of the negative electrode member along the predetermined stacking direction. Since the respective layers are stacked so that their masses are increased, the variation in the mass ratio of the negative electrode active material to the positive electrode active material on each facing surface can be reduced in each pair of the positive electrode member and the negative electrode member facing each other. Thereby, since the charging / discharging reaction performed by each opposing surface of the some positive electrode member and negative electrode member to laminate | stack progresses substantially uniformly, a capacity | capacitance maintenance factor (cycle life) can be improved. Moreover, the safety | security in the case of assuming misuse, such as an overcharge state, can be improved.

  As described above, according to the present invention, in a battery in which a plurality of positive electrode members and negative electrode members are alternately stacked with separator members interposed therebetween, the capacity retention rate (cycle life) can be improved. Safety in an overcharged state can be improved.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic plan view showing an example of a non-aqueous electrolyte battery as one embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view as seen from the direction along the line II-II in FIG. FIG. 3 is a partial cross-sectional view, and FIG. 3 is a partial cross-sectional view showing, in an enlarged manner, a cross section viewed from the direction along line III-III in FIG.

  As shown in FIG. 1, the battery 100 includes a power generation element 10, an exterior member 20 that houses and seals the power generation element 10, and is connected to the power generation element 10 via a plurality of current collectors. It consists of a positive electrode terminal 30 and a negative electrode terminal 40 which are led out from the outer periphery.

  As shown in FIG. 2 and FIG. 3, the power generation element 10 includes a plurality of positive electrode members 11, a plurality of negative electrode members 12, each between a plurality of positive electrode members 11 and a plurality of negative electrode members 12. It includes a plurality of separator members 13 disposed so as to intervene and a non-aqueous electrolyte (not shown). Each of the plurality of positive electrode members 11 and each of the plurality of negative electrode members 12 are alternately stacked with each of the plurality of separator members 13 interposed therebetween. The positive electrode member 11, the negative electrode member 12, and the separator member 13 are formed in a plate shape, a film shape, a foil shape, or the like. For example, a laminate in which a plurality of film-like positive electrode members 11 and negative electrode members 12 are laminated in close contact with each other via a separator member 13 is filled in an exterior member 20 made of an aluminum laminate film. As shown in FIG. 3, the plurality of negative electrode members 12 are connected to the negative electrode terminal 40 via the plurality of current collecting members 41. Although not shown in figure, the some positive electrode member 11 is similarly connected to the positive electrode terminal 30 (FIG. 1).

  As shown in FIGS. 2 and 3, the plurality of positive electrode members 11 are stacked so that the mass of each of the positive electrode members 11 increases along a predetermined stacking direction, in the drawing, from the top to the bottom. Has been. Specifically, in the example shown in FIG. 2 and FIG. It is laminated so as to increase the mass according to 1-17.

  As shown in FIGS. 2 and 3, the plurality of negative electrode members 12 are laminated so that the mass of each of the negative electrode members 12 increases along a predetermined lamination direction, in the drawing, from the top to the bottom. Has been. Specifically, in the example shown in FIG. 2 and FIG. It is laminated so that the mass increases according to 1-18.

  The positive electrode member 11 is configured by forming a positive electrode active material layer on the surface of the current collector. The negative electrode member 12 is configured by forming a negative electrode active material layer on the surface of the current collector.

  In the battery 100 of the present invention, the plurality of positive electrode members 11 are stacked so that the mass of each of the positive electrode members 11 increases along the predetermined stacking direction, and the plurality of negative electrode members 12 extend along the predetermined stacking direction. The negative electrode member 12 is laminated so that the mass of each of the negative electrode members 12 is increased. Therefore, in each pair of the positive electrode member 11 and the negative electrode member 12, the mass ratio of the negative electrode active material to the positive electrode active material on each facing surface varies. Can be small. As a result, the charge / discharge reaction performed on the opposing surfaces of the plurality of stacked positive electrode members 11 and negative electrode members 12 proceeds substantially uniformly, so that the capacity retention rate (cycle life) can be improved. Moreover, the safety | security in the case of assuming misuse, such as an overcharge state, can be improved.

  For example, the positive electrode member 11 is formed by applying a positive electrode mixture containing a positive electrode active material, a binder, and a conductive additive onto the surface of a current collector made of aluminum foil, and drying the positive electrode active material layer. It is produced by forming on the surface of a current collector.

  In general, as the positive electrode active material, a metal oxide, a metal sulfide, or a specific polymer can be used depending on the type of the target battery.

When constituting a lithium ion secondary battery, metal sulfides or oxides such as TiS ₂ , MoS ₂ , NbSe ₂ , V ₂ O ₅ can be used as the positive electrode active material. In addition, LiM _x O ₂ (in the chemical formula, M represents one or more transition metals, x varies depending on the charge / discharge state of the battery, and is usually 0.05 or more and 1.10 or less as a positive electrode active material of the lithium ion secondary battery. Lithium composite oxide mainly composed of As the transition metal M constituting this lithium composite oxide, Co, Ni, Mn and the like are preferable. Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiNi _y Co _1-y O ₂ (where 0 <y <1), and Li _{1 + a} (Ni _x Co _y Mn _z ) O. _2-b (in the chemical formula, −0.1 <a <0.2, x + y + z = 1, −0.1 <b <0.1), LiMn ₂ O _{4 and the} like. These lithium composite oxides can generate a high voltage and become a positive electrode active material having an excellent energy density. In order to produce the positive electrode member 11, a plurality of these positive electrode active materials may be used in combination.

  Moreover, as a binder contained in said positive electrode mixture, the well-known binder normally used for the positive electrode mixture of a battery can be used, A conductive agent is used for said positive electrode mixture. For example, known additives can be added.

  For example, in the negative electrode member 12, a negative electrode mixture containing a negative electrode active material and a binder is uniformly applied on the surface of a current collector made of copper foil and dried to collect the negative electrode active material layer. It is made by forming on the surface of the body.

When constituting a lithium secondary battery, it is preferable to use a material capable of doping and dedoping lithium as the negative electrode active material. As a material that can be doped or dedoped with lithium, for example, a carbon material such as a non-graphitizable carbon material or a graphite material can be used. Specifically, carbon materials such as pyrolytic carbons, cokes, graphites, glassy carbon fibers, organic polymer compound fired bodies, carbon fibers, and activated carbon can be used. Examples of the cokes include pitch coke, needle coke, and petroleum coke. Moreover, said organic polymer compound fired body means what carbonized by baking a phenol resin, furan resin, etc. at a suitable temperature. In addition to the carbon material described above, as a material that can be doped or dedoped with lithium, a polymer such as polyacetylene or polypyrrole, or an oxide such as SnO ₂ or Li ₄ Ti ₅ O ₁₂ (lithium titanate) can also be used. .

  Moreover, as a binder contained in said negative electrode mixture, the well-known binder normally used for the negative electrode mixture of a lithium ion battery can be used, In said negative electrode mixture, Known additives and the like can be added.

The nonaqueous electrolytic solution is prepared by dissolving an electrolyte in a nonaqueous solvent. As the electrolyte, for example, a solution obtained by dissolving LiPF ₆ at a concentration of 1.0 mol / L in a non-aqueous solvent is used. As an electrolyte other than LiPF ₆ , lithium salts such as LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiAlCl ₄ , LiSiF ₆ are used. Can be mentioned. Among these, it is desirable from the viewpoint of oxidation stability that LiPF ₆ or LiBF ₄ is particularly used as the electrolyte. Such an electrolyte is preferably used by being dissolved in a nonaqueous solvent at a concentration of 0.1 mol / L to 3.0 mol / L, and dissolved at a concentration of 0.5 mol / L to 2.0 mol / L. More preferably, it is used. As the non-aqueous solvent, for example, a mixture of propylene carbonate, ethylene carbonate, and diethyl carbonate at a volume ratio of 5-20: 20-30: 60-70 is used. Other non-aqueous solvents include: cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as diethyl carbonate and dimethyl carbonate; carboxylic acid esters such as methyl propionate and methyl butyrate; γ-butyllactone, sulfolane, Ethers such as 2-methyltetrahydrofuran and dimethoxyethane can be used. These non-aqueous solvents may be used alone or in combination of two or more. Among these, it is preferable from the point of oxidation stability to use carbonate ester as the non-aqueous solvent.

  In the above-described embodiment, one separator member is interposed between the positive electrode member and the negative electrode member, but a plurality of separator members may be interposed. The material of the plurality of separator members may be the same or different.

  In the above embodiment, a plurality of strip-shaped separator members are used as the separator member in the same manner as the positive electrode member and the negative electrode member. However, the separator member may be long. In that case, the separator member is folded into ninety nines so that the positive electrode member and the negative electrode member are interposed between the separator members, or the separator member is wound into a square shape having a flat portion and the positive electrode member is interposed between the separator members. And a negative electrode member may be interposed. At this time, a plurality of separator members may be folded or wound.

  A nonaqueous electrolyte battery 100 as shown in FIGS. 1 to 3 was produced as follows.

The plate-like positive electrode member (positive electrode plate) 11 is made of a positive electrode mixture containing LiCoO ₂ as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, and acetylene black as a conductive additive. The positive electrode active material layer was formed on the surface of the current collector by applying it on the surface of the current collector made of aluminum foil and drying it. At this time, an end portion of the aluminum foil as a current collector was provided with a portion where the surface of the aluminum foil was exposed without applying the positive electrode mixture.

  A plate-like negative electrode member (negative electrode plate) 12 is a current collector made of a copper foil containing a negative electrode mixture containing a graphite-based material as a negative electrode active material and polyvinylidene fluoride (PVdF) as a binder. The negative electrode active material layer was formed on the surface of the current collector. Under the present circumstances, the part which the surface of the copper foil exposed was provided in the edge part of the copper foil as an electrical power collector, without apply | coating a negative mix.

  The positive electrode member 11 and the negative electrode member 12 obtained as described above were brought into close contact with each other via a separator member 13 made of, for example, a microporous polyethylene film, and a laminate was formed by laminating a large number of sheets.

  Then, in the laminate obtained above, the exposed portions of the aluminum foil in the plurality of positive electrode members 11 are superposed on the positive terminal 30 and ultrasonically welded to the positive electrode terminal 30, and the exposed portions of the copper foil in the plurality of negative electrode members 12 are overlapped. The terminal 40 was ultrasonically welded.

  Next, an aluminum laminated film in which an outer protective layer made of resin, an intermediate gas barrier layer made of aluminum, and an inner adhesive layer made of resin were laminated and integrated was produced. The above laminate was housed inside the exterior member 20 made of this aluminum laminate film. Thereafter, a part of the outer periphery of the exterior member 20 was left open in order to use it as an electrolyte inlet, and the other outer periphery of the exterior member 20 was thermally welded.

Then, a nozzle was inserted from the electrolyte solution injection port, and a nonaqueous electrolyte solution was injected into the battery 100. The non-aqueous electrolyte was prepared by dissolving the electrolyte in a non-aqueous solvent. As the electrolyte, a solution obtained by dissolving LiPF ₆ at a concentration of 1.0 mol / L in a non-aqueous solvent was used. As the non-aqueous solvent, a mixture of propylene carbonate, ethylene carbonate, and diethyl carbonate at a volume ratio of 5:25:70 was used.

  Next, a part of the outer periphery used as the electrolyte solution inlet is temporarily sealed, and after initial charging under predetermined conditions, the temporary sealing is opened again, and heat sealing is performed while reducing the pressure, and then the main seal is sealed. Stopped.

  In this way, ten non-aqueous electrolyte batteries 100 of the present invention and comparative examples (sample numbers 1 to 10) were produced.

  In the above configuration, in the non-aqueous electrolyte battery 100 of the present invention example, as shown in FIGS. 2 and 3, 17 (No. 1 to No. 17) positive electrode members 11 and 18 (No. 1 to No. 1). No. 18) negative electrode member 12 was laminated to produce a battery with a capacity of 4 Ah. At this time, the masses of all the positive electrode members 11 and the negative electrode members 12 of the example of the present invention were measured with a measuring instrument.

  Table 1 shows the maximum value, the minimum value, the center value, the average value, and the standard deviation of the masses of the positive electrode plate and the negative electrode plate used in all the samples of the battery of the present invention.

  As shown in FIG. 2 and FIG. 1-No. The negative electrode member 12 is laminated in the order of lamination No. 1-No. 18 was laminated so as to increase the mass.

  The masses of the positive electrode member 11 from the first sheet (No. 1) to the 17th sheet (No. 17) measured before lamination are shown in FIGS. In FIG. 4, the stacking order No. for all 10 samples of the present invention example. 1-No. 17 and the respective masses of the positive electrode plate are shown. In FIG. 1-No. The relationship between 17 and each mass of a positive electrode plate is shown.

  Moreover, the mass of the negative electrode member 12 from the 1st sheet | seat (No. 1) measured before lamination | stacking to the 18th sheet | seat (No. 18) is shown in FIG. 6 and FIG. In FIG. 6, the stacking order No. for all 10 samples of the present invention example. 1-No. 18 and the respective masses of the negative electrode plate are shown. In FIG. 1-No. The relationship between 18 and each mass of a negative electrode plate is shown.

  As shown in FIGS. 2 and 3, 17 positive electrode members 11 and 18 negative electrode members 12 are laminated with a separator member 13 interposed therebetween, that is, negative electrode / separator / positive electrode / separator / negative electrode / separator / When stacked in the order of positive electrode... Negative electrode / separator / positive electrode / separator / negative electrode, there are 34 positive and negative electrode facing surfaces corresponding to the number of front and back surfaces of the positive electrode member 11. For each of the 34 positive and negative electrode facing surfaces, the ratio (AC ratio) of the negative electrode active material layer mass to the positive electrode active material layer mass was measured. In addition, the mass of each aluminum foil used as each collector of the positive electrode member 11 of this invention example is equal, and the mass of each copper foil used as each collector of the negative electrode member 12 is equal. Assumed. In addition, since the active material of the front and back of a collector cannot isolate | separate and measure a weight, the positive electrode active material layer mass and the negative electrode active material layer mass were computed on the collector front and back being equivalently applied.

  The positive and negative electrode facing surfaces of the 34th surface are arranged in the order of distance No. 1-No. 34, the inter-electrode order No. 1-No. The relationship between 34 and the AC ratio is shown in FIGS. In FIG. 8, the inter-electrode order No. for all 10 samples of the example of the present invention. 1-No. 34 and the AC ratio. In FIG. 1-No. 34 shows the relationship between AC and AC ratio.

  On the other hand, in the non-aqueous electrolyte battery 100 of the comparative example, 17 (No. 1 to No. 17) positive electrode members 11 and 18 (No. 1 to No. 18) negative electrode members 12 randomly selected are used. A battery having a capacity of 4 Ah was produced by stacking. At this time, the mass of each of the positive electrode member 11 and the negative electrode member 12 of the comparative example was measured.

  Table 2 shows the maximum value, the minimum value, the center value, the average value, and the standard deviation of the masses of the positive electrode plate and the negative electrode plate used in all the samples of the battery of the comparative example.

  The mass of the positive electrode member 11 from the first sheet (No. 1) to the 17th sheet (No. 17) measured before lamination is shown in FIGS. In FIG. 10, the stacking order No. for all 10 samples of the comparative examples. 1-No. 17 and the respective masses of the positive electrode plate are shown. In FIG. 1-No. The relationship between 17 and each mass of a positive electrode plate is shown.

  Moreover, the mass of the negative electrode member 12 from the 1st sheet (No. 1) to the 18th sheet (No. 18) measured before lamination is shown in FIGS. In FIG. 12, the stacking order No. for all 10 samples of the comparative examples. 1-No. 18 and the respective masses of the negative electrode plate are shown. In FIG. 1-No. The relationship between 18 and each mass of a negative electrode plate is shown.

  Also in the comparative example, the ratio (AC ratio) of the negative electrode active material layer mass to the positive electrode active material layer mass was measured for each of the 34 positive and negative electrode facing surfaces in the same manner as in the present invention example. It is assumed that the mass of each aluminum foil used as each current collector of the positive electrode member 11 is equal, and the mass of each copper foil used as each current collector of the negative electrode member 12 is equal. The positive electrode active material layer mass and the negative electrode active material layer mass were calculated.

  The positive and negative electrode facing surfaces of the 34th surface are arranged in the order of distance No. 1-No. 34, the inter-electrode order No. 1-No. FIG. 14 and FIG. 15 show the relationship between 34 and the AC ratio. In FIG. 1-No. 34 and the AC ratio. In FIG. 1-No. 34 shows the relationship between AC and AC ratio.

  Comparing FIGS. 8 to 9 and FIGS. 14 to 15, in each sample of the example of the present invention, the ratio (AC ratio) of the negative electrode active material layer mass to the positive electrode active material layer mass on each positive and negative electrode facing surface is a comparison. It can be seen that the variation is small compared to the AC ratio of the example.

  A charge / discharge cycle test was carried out under the following conditions using 10 batteries of the present invention example and the comparative example produced as described above.

(Test conditions)
Charging: Start at 4A / 4.2V, until the end current reaches 0.04A Pause: 10 minutes Discharge: Start at 4A, until 2.7V Number of cycles: 500 cycles Perform 500 cycles of charge / discharge cycle test After that, the capacity retention rate at 4A was calculated. The capacity retention rate was determined by dividing the ratio of the discharge capacity after 500 cycles to the initial capacity at 100 minutes. The results are shown in Table 3.

  As is apparent from the results of Table 3, the average value of the capacity retention rate of the battery of the comparative example is about 81%, whereas the average value of the capacity maintenance rate of the battery of the present invention example is about 91%. Thus, according to the present invention, it is understood that the capacity retention rate (cycle life) can be improved in a battery in which a plurality of positive electrode members and negative electrode members are alternately stacked with separator members interposed therebetween.

  It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  The battery of the present invention can be used as a power source for portable electronic devices such as a mobile phone and a portable personal computer, a power source for automobiles, and the like.

1 is a schematic plan view showing an example of a non-aqueous electrolyte battery as one embodiment of the present invention. It is a fragmentary sectional view which expands and shows the cross section seen from the direction along the II-II line of FIG. It is a fragmentary sectional view which expands and shows the cross section seen from the direction along the III-III line of FIG. For all 10 samples of the present invention, the stacking order No. 1-No. It is a figure which shows the relationship between 17 and each mass of a positive electrode plate. For each of sample numbers 1 to 10 in the example of the present invention, the stacking order No. 1-No. It is a figure which shows the relationship between 17 and each mass of a positive electrode plate. For all 10 samples of the present invention, the stacking order No. 1-No. It is a figure which shows the relationship between 18 and each mass of a negative electrode plate. For each of sample numbers 1 to 10 in the example of the present invention, the stacking order No. 1-No. It is a figure which shows the relationship between 18 and each mass of a negative electrode plate. For all 10 samples of the example of the present invention, the no. 1-No. It is a figure which shows the relationship between 34 and AC ratio. For each of the sample numbers 1 to 10 of the example of the present invention, the inter-electrode order No. 1-No. It is a figure which shows the relationship between 34 and AC ratio. For all 10 samples of the comparative examples, the stacking order No. 1-No. It is a figure which shows the relationship between 17 and each mass of a positive electrode plate. For each sample number 1 to 10 in the comparative example, the stacking order No. 1-No. It is a figure which shows the relationship between 17 and each mass of a positive electrode plate. For all 10 samples of the comparative examples, the stacking order No. 1-No. It is a figure which shows the relationship between 18 and each mass of a negative electrode plate. For each sample number 1 to 10 in the comparative example, the stacking order No. 1-No. It is a figure which shows the relationship between 18 and each mass of a negative electrode plate. For all 10 samples of the comparative examples, the inter-electrode order No. 1-No. It is a figure which shows the relationship between 34 and AC ratio. For each of sample numbers 1 to 10 of the comparative example, the inter-electrode order No. 1-No. It is a figure which shows the relationship between 34 and AC ratio.

Explanation of symbols

  10: power generation element, 11: positive electrode member, 12: negative electrode member, 13: separator member, 20: exterior member, 30: positive electrode terminal, 40: negative electrode terminal, 100: battery.

Claims (1)

A plurality of positive electrode members comprising a positive electrode active material and a current collector;
In a battery in which a plurality of negative electrode members made of a negative electrode active material and a current collector are alternately stacked with a separator member interposed therebetween,
The plurality of positive electrode members are stacked such that the mass of each of the positive electrode members increases along a predetermined stacking direction, and the plurality of negative electrode members has a mass of each of the negative electrode members along the predetermined stacking direction. Batteries that are stacked to be larger.

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