JP2019021537A - Electrode, battery using the electrode, and method of manufacturing the battery - Google Patents

Abstract

To provide a battery improved in energy density and output density.SOLUTION: A battery includes a foundation part 122 and a plurality of projecting portions 128 arranged to be spaced apart from each other and projecting from the foundation part 122. Each of the projecting portions 128 comprises: a projecting post part 124 projecting from the foundation part 122; and a projecting tip part 126 projecting from the projecting post part 124. The maximum width Wh of the projecting tip part 126 is larger than the minimum width Wp of the projecting post part 124, in a direction where the projecting portions 128 are arranged.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrode, a battery using the electrode, and a method for manufacturing the battery.

  In recent years, electric vehicles, which are rapidly spreading, are required to have a travel characteristic such as a long travel distance per charge and a quick travel. For this reason, the battery mounted in the electric vehicle is required to have a large energy density (Wh / Kg) and output density (W / Kg). In addition, since an electric vehicle has a limited battery installation space, it is required to reduce the size of the battery.

  However, since the energy density of the battery and the output density of the battery are in a trade-off relationship, it is difficult to create a battery with a high energy density and a high output. In order to produce a battery having both a high energy density and a high output density of the battery, an electrode active material and an electrolytic solution have been developed. On the other hand, as shown in Patent Document 1 below, a battery structure in which the electrode structure is made three-dimensional has been developed.

International Publication No. 2014/038455

  Certainly, according to the battery having the electrode structure disclosed in Patent Document 1, the energy density can be improved without lowering the output density of the battery.

  However, since the electrode structure shown in Patent Document 1 has a comb shape in which both positive and negative electrodes repeat rectangular irregularities, current tends to concentrate on the corners of the irregularities. For this reason, the current distribution between the positive and negative electrodes becomes non-uniform, and it is difficult to improve the energy density and the output density.

  In order to further improve the energy density and the output density, theoretically, a high-resolution comb shape in which rectangular irregularities are repeated at a higher resolution (fine pitch) may be used. However, it is not practical to use a high-resolution comb-shaped electrode because of problems in productivity, reliability, and manufacturing.

  The present invention has been made to solve the above-described problems of the prior art, and can improve the energy density of the battery and the output density of the battery, and a battery using the electrode. Another object is to provide a method for manufacturing the battery.

  In order to achieve the above object, an electrode according to the present invention includes a base portion and a plurality of protrusion portions that are arranged at intervals from each other and protrude from the base portion. Each of the protrusions is composed of a protrusion column part protruding from the base part and a protrusion tip part protruding from the protrusion column part, and the maximum width of the protrusion tip part in the direction in which the protrusions are aligned is the maximum width of the protrusion column part. Bigger than narrow.

  In order to achieve the above object, a battery according to the present invention uses the above electrode as a positive electrode and a negative electrode, and a negative electrode protrusion is positioned between adjacent protrusions of the positive electrode, and the positive electrode protrusion and the negative electrode protrusion A separator is interposed between the parts.

  In order to achieve the above object, a battery manufacturing method according to the present invention includes a step of forming a positive electrode or negative electrode base portion with a 3D printer, and a positive electrode or negative electrode protrusion strut portion and a separator alternately. A step of forming a positive electrode or negative electrode protrusion strut, a separator, a negative electrode or positive electrode protrusion tip, and a separator repeatedly, and a positive electrode or negative electrode protrusion tip, a separator, a negative electrode or positive electrode protrusion strut, a separator The step of repeatedly forming the step, the step of alternately forming the negative electrode or positive electrode protrusion struts and the separator, and the step of forming the base portion of the negative electrode or positive electrode are performed.

  According to the electrode according to the present invention and the battery using the electrode, the energy density of the battery and the output density of the battery can be improved.

  According to the battery manufacturing method of the present invention, a battery capable of improving energy density and output density can be manufactured by a 3D printer.

1 is a cross-sectional view of a battery according to Embodiment 1. FIG. It is a perspective view of the positive electrode of the battery described in FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a method for manufacturing the battery according to Embodiment 1. FIG. 6 is a diagram showing a modification of the battery according to Embodiment 1. FIG. 6 is a cross-sectional view of a battery according to Embodiment 2. FIG. 6 is a diagram showing a modification of the battery according to Embodiment 2. FIG. 6 is a cross-sectional view of a battery according to Embodiment 3. FIG. FIG. 10 is a diagram showing a modification of the battery according to Embodiment 3. 6 is a cross-sectional view of a battery according to Embodiment 4. FIG. FIG. 10 is a view showing a modification of the battery according to Embodiment 4. 6 is a cross-sectional view of a battery according to Embodiment 5. FIG. FIG. 10 is a view showing a modification of the battery according to Embodiment 5. It is a figure where it uses for description of the current density distribution between the positive electrode and negative electrode of the conventional battery. It is a figure which shows the simulation result of the conventional battery and the battery which concerns on Embodiment 1. FIG. It is a graph which shows the SOC-voltage characteristic (1C) of the conventional battery and the battery which concerns on Embodiment 1. FIG. It is a graph which shows the SOC-voltage characteristic (5C) of the conventional battery and the battery which concerns on Embodiment 1. FIG. It is a graph which shows the DOD-discharge rate characteristic of the conventional battery and the battery which concerns on Embodiment 1. FIG.

  Hereinafter, with reference to the drawings, embodiments of the present invention will be described by dividing them from [Embodiment 1] to [Embodiment 5]. In addition, the same code | symbol was used for the same member in the figure. In addition, the dimensional ratios in the drawings may be exaggerated for convenience of explanation, and may be different from the actual ratios.

[Embodiment 1]
(Battery configuration)
1 is a cross-sectional view of a battery according to Embodiment 1. FIG. Specifically, the battery 100 illustrated in FIG. 1 serves as a power generation element of a lithium ion secondary battery having a flat rectangular shape. Generally, a lithium ion secondary battery is configured by connecting a large number of batteries 100 in parallel and in series.

  The battery 100 includes a positive electrode current collector 110, a positive electrode 120, a separator 150, a negative electrode 170, and a negative electrode current collector 160. The positive electrode current collector 110 and the positive electrode 120 constitute a positive electrode 130, and the negative electrode current collector 160 and the negative electrode 170 constitute a negative electrode 180.

  In the battery 100, the positive electrode 130 and the negative electrode 180 are arranged to face each other. The protrusions 178 of the negative electrode 180 are positioned alternately between the adjacent protrusions 128 of the positive electrode 130. The size and shape of the protrusion 128 of the positive electrode 130 are the same as the size and shape of the protrusion 178 of the negative electrode 180. A separator 150 is interposed between the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

An aluminum foil is used for the positive electrode current collector 110. The positive electrode 120 is formed of a positive electrode active material, and a composite oxide such as LiMn ₂ O ₄ , LiCoO ₂ , and LiNiO ₂ is used as the positive electrode active material. The positive electrode active material is bound by a binder such as polyvinylidene fluoride (PVdF), and a conductive aid such as a carbon material is added as necessary.

  The separator 150 is a sheet-like porous body and holds an electrolytic solution. For example, a polyolefin microporous membrane is used as the separator 150, and an electrolytic solution in which a lithium salt such as LiPF6 is dissolved in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) is used. Electrolytic solution additives such as methylenemethane disulfonate (MMDS), vinylene carbonate (VC), and fluoroethylene carbonate (FEC) are added to the electrolytic solution.

  A copper foil is used for the negative electrode current collector 160. The negative electrode 170 is formed of a negative electrode active material, and a carbon material such as graphite, carbon black, and hard carbon is used for the negative electrode active material. The negative electrode active material is bound by an aqueous binder such as a styrene butadiene rubber (SBR) / carboxymethyl cellulose (CMC) mixed binder, and a conductive aid such as a carbon material is added as necessary.

  In the battery 100 according to Embodiment 1, the shape of the protruding portion 128 of the positive electrode 130 and the shape of the protruding portion 178 of the negative electrode 180 are devised to have a circular shape including only a curved shape. In addition, the size and shape of the protruding portion 128 of the positive electrode 130 are the same as the size and shape of the protruding portion 178 of the negative electrode 180. As a result, the distribution of current flowing between the protrusions 128 and 178 becomes uniform, and local current concentration can be avoided. Therefore, it is possible to provide a high capacity, high output battery 100 with improved energy density and output density.

(Configuration of electrode)
FIG. 2 is a perspective view of the positive electrode 130 of the battery 100 illustrated in FIG. 1. As shown in FIG. 2, the positive electrode 130 is obtained by forming the positive electrode 120 on the positive electrode current collector 110.

  The positive electrode 120 includes a base portion 122 and a plurality of protrusions 128 as shown in the drawing. The base portion 122 is formed on the positive electrode current collector 110. The protruding portions 128 are arranged at intervals from each other and protrude from the base portion 122. Each of the protrusions 128 includes a protrusion support part 124 protruding from the base part 122 and a protrusion tip part 126 protruding from the protrusion support part 124. The maximum width (tip width: Wh) of the protrusion tip 126 in the direction in which the protrusions 128 are arranged (X direction in the drawing) is larger than the minimum width (post width: Wp) of the protrusion support 124. Specifically, Wh ≧ 1.2Wp.

  Thus, by making the maximum width Wh of the protrusion tip portion 126 larger than the minimum width Wp of the protrusion support portion 124, the surface area of the protrusion 128 increases. For this reason, it is possible to avoid concentration of current flowing in and out of the protrusion 128. Therefore, by using the positive electrode 130 for the battery 100, it is possible to provide a high-capacity, high-power battery 100 with improved energy density and power density.

  Here, the base portion 122 includes the surface after the movement when the surface of the positive electrode current collector 110 in the positive electrode 120 is moved in the Z direction until it contacts the outer surface of the positive electrode 120, and the positive electrode A portion having a thickness formed by the surface of the current collector 110. Accordingly, the base portion 122 connects the adjacent protrusions 128. The presence of the base portion 122 is very important in terms of ensuring a sufficient contact area with the positive electrode current collector 110. The definition of the base part 122 is the same in the embodiment 1-5.

  The protrusion tip 126 has a thickness (circular diameter in FIG. 2) in the illustrated Z direction of a shape (circular in FIG. 2) virtually formed by the outer shape of the distal end portion of the positive electrode 120. It is the tip part. The definition of the protrusion tip portion 126 is the same as in Embodiment 1-5.

  The protruding support column portion 124 is a portion between the base portion 122 and the protruding tip portion 126. The definition of the protrusion support | pillar part 124 is the same in Embodiment 1-5.

  In addition, when the protrusion 128 is cut vertically along the direction in which the protrusions 128 are arranged, the cross-sectional area of the protrusion tip 126 is larger than the cross-sectional area of the protrusion support 124.

  In this way, by making the cross-sectional area of the protrusion tip portion 126 larger than the cross-sectional area of the protrusion support portion 124, the electrode capacity balance between the protrusion tip portion 126 and the base portion 122 can be easily adjusted, and the ion movement distance can be reduced. it can. For this reason, it is possible to avoid the concentration of current flowing in and out of the protrusion tip portion 126. Therefore, by using the positive electrode 130 for the battery 100, it is possible to provide a high-capacity, high-power battery 100 with improved energy density and power density.

  As shown in FIG. 2, the outer shape of the cross section of the protrusion 128 when the protrusion 128 is cut vertically along the direction in which the protrusions 128 are arranged is formed only by a curve.

  In this way, when the outer shape of the cross section of the protrusion 128 is formed by only a curve, it is possible to avoid the concentration of current flowing in and out of the protrusion 128. Therefore, by using the positive electrode 130 for the battery 100, it is possible to provide a high-capacity, high-power battery 100 with improved energy density and power density.

  Further, the protrusion 128 extends in a direction (Y direction in the drawing) intersecting the direction in which the protrusions 128 are arranged.

  As described above, when the protrusion 128 is extended in a direction intersecting with the direction in which the protrusions 128 are arranged, the surface area of the protrusion 128 is increased. For this reason, it is possible to avoid concentration of current flowing in and out of the protrusion 128. Therefore, by using the positive electrode 130 for the battery 100, it is possible to provide a high-capacity, high-power battery 100 with improved energy density and power density.

  The configuration of the positive electrode 130 is as described above. Note that the configuration of the negative electrode 180 illustrated in FIG. 1 is the same as the configuration of the positive electrode 130. Therefore, the size and shape of the protrusion 128 of the positive electrode 130 are the same as the size and shape of the protrusion 178 of the negative electrode 180, and the positive electrode 130 and the negative electrode 180 have a symmetrical shape.

(Battery manufacturing method)
Next, a method for manufacturing the battery shown in FIG. 1 will be described. The battery 100 shown in FIG. 1 is manufactured by the following procedure using a 3D printer.

Forming a base portion 122 of the positive electrode 130 on the positive electrode current collector 110;
Alternately forming protruding post portions 124 and separators 150 of the positive electrode 130;
Repetitively forming the protrusion support 124, the separator 150, the protrusion tip 176 of the negative electrode 180, and the separator 150;
Repeatedly forming the protrusion tip 126 of the positive electrode 130, the separator 150, the protrusion support 174 of the negative electrode 180, and the separator 150;
Alternately forming protruding post portions 174 and separators 150 of the negative electrode 180;
Forming a base portion 172 of the negative electrode 180;
Attaching the negative electrode current collector 160 to the base portion 172;
Is performed to manufacture the battery 100.

  The battery 100 shown in FIG. 1 can be manufactured by sequentially stacking the respective parts in such a procedure. By manufacturing the battery 100 using the above manufacturing method, it is possible to provide a high-capacity, high-power battery 100 with improved energy density and power density.

  3 to 9 are views showing a method for manufacturing the battery 100 according to the first embodiment. It is assumed that the head of the 3D printer moves from the left side to the right side in the figure.

  First, as shown in FIG. 3, the base portion 122 of the positive electrode 130 (see FIG. 2) is formed on the positive electrode current collector 110.

  Next, as shown in FIG. 4, the protruding support portions 124 and the separators 150 are alternately formed so as to protrude on the base portion 122 of the positive electrode 130.

  Next, as shown in FIG. 5, the protrusion support 124, the separator 150, the protrusion tip 176 of the negative electrode 180, and the separator 150 are repeatedly formed.

  Next, as shown in FIG. 6, the protrusion tip 126, the separator 150, the protrusion strut 174 of the negative electrode 180, and the separator 150 are repeatedly formed so as to protrude onto the protrusion strut 124 of the positive electrode 130.

  Next, as shown in FIG. 7, the protruding support portions 174 and the separators 150 of the negative electrode 180 are alternately formed.

  Next, as shown in FIG. 8, the base portion 172 is formed on the protruding support portion 174 of the negative electrode 180.

  Finally, as shown in FIG. 9, the negative electrode current collector 160 is attached to the base portion 172.

  The battery 100 shown in FIG. 1 is formed by the procedure as described above.

[Modification of Embodiment 1]
FIG. 10 is a diagram illustrating a modification of the battery 100 according to the first embodiment. The configuration of battery 100A according to this modification is the same as that of battery 100 shown in FIG. 1 except for the points described below.

  In the comparison between the battery 100A according to the modified example and the battery 100 shown in FIG. 1, the only difference is the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

  That is, the size and shape of the protrusion 128 of the positive electrode 130 are different from the size and shape of the protrusion 178 of the negative electrode 180. Further, the shape of the protrusion tip portion 126 that forms the protrusion portion 128 of the positive electrode 130 is similar to the shape of the protrusion tip portion 176 that forms the protrusion portion 178 of the negative electrode 180.

  Comparing the shape of the protrusion tip 126 in FIG. 10 with the shape of the protrusion tip 176, the protrusion tip 126 is circular, whereas the protrusion tip 176 is not circular but elliptical. I understand. That is, it can be seen that the positive electrode 130 and the negative electrode 180 have an asymmetric shape.

  Thus, even if the positive electrode 130 and the negative electrode 180 have an asymmetric shape, the outer shape of the cross section of the protrusion 128 and the protrusion 178 is formed only by a curve, so the protrusion 128 and the protrusion Concentration of current flowing in and out of 178 can be avoided. Therefore, it is possible to provide a high capacity, high output battery 100 with improved energy density and output density.

[Embodiment 2]
FIG. 11 is a cross-sectional view of the battery according to the second embodiment. The configuration of the battery 100-2 according to the second embodiment is the same as the configuration of the battery 100 illustrated in FIG. 1 except for the points described below.

  In the battery 100-2, the outer shape of the cross section of the protrusion 128 when the protrusion 128 of the positive electrode 130 is cut vertically along the direction in which the protrusions 128 are arranged is formed with a curve and a straight line. . The outer shape of the cross section of the protruding portion 178 of the negative electrode 180 is also the same as the outer shape of the cross section of the protruding portion 128 of the positive electrode 130.

  In the comparison between the battery 100-2 and the battery 100 shown in FIG. 1, different portions are the shape of the protruding portion 128 of the positive electrode 130 and the shape of the protruding portion 178 of the negative electrode 180. The shape of the protrusion 128 and the protrusion 178 of the battery 100-2 is a mushroom shape, and the shape of the protrusion 128 and the protrusion 178 of the battery 100 shown in FIG. 1 is a circle.

  As described above, even when the shape of the protrusion 128 of the positive electrode 130 and the shape of the protrusion 178 of the negative electrode 180 is a mushroom shape with a curved line and a straight line, the outer shape of the cross section of the protrusions 128 and 178 includes a curved portion. Therefore, it is possible to avoid the concentration of current between the projecting tip portions 126 and 176. Therefore, a high-capacity, high-power battery 100-2 with improved energy density and power density can be provided.

[Modification of Embodiment 2]
FIG. 12 is a diagram illustrating a modification of the battery 100-2 according to the second embodiment. The configuration of battery 100A-2 according to this modification is the same as that of battery 100-2 shown in FIG. 11 except for the points described below.

  In the comparison between the battery 100A-2 according to the modification and the battery 100-2 shown in FIG. 11, the only difference is the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

  That is, the size and shape of the protrusion 128 of the positive electrode 130 are different from the size and shape of the protrusion 178 of the negative electrode 180. Further, the shape of the protrusion tip portion 126 that forms the protrusion portion 128 of the positive electrode 130 is similar to the shape of the protrusion tip portion 176 that forms the protrusion portion 178 of the negative electrode 180.

  Comparing the shape of the protrusion tip portion 126 and the shape of the protrusion tip portion 176 in FIG. 12, it can be seen that the mushroom shape is similar, but the thickness of the mushroom-shaped umbrella portion is different. That is, it can be seen that the positive electrode 130 and the negative electrode 180 have an asymmetric shape.

  As described above, even if the positive electrode 130 and the negative electrode 180 have asymmetric shapes, the outer shape of the cross section of the protrusion 128 and the protrusion 178 includes a curved portion. Concentration of current flowing in and out of the portion 178 can be avoided. Therefore, a high-capacity, high-power battery 100A-2 with improved energy density and power density can be provided.

[Embodiment 3]
FIG. 13 is a cross-sectional view of the battery according to the third embodiment. The configuration of the battery 100-3 according to the third embodiment is the same as the configuration of the battery 100 illustrated in FIG. 1 except for the points described below.

  In the battery 100-3, the outer shape of the cross section of the protrusion 128 when the protrusion 128 of the positive electrode 130 is cut vertically along the direction in which the protrusions 128 are arranged is formed with a curve and a straight line. . Further, the corners of the outer shape of the cross section of the protrusion 128 are chamfered in a curved line at least in the range of 10% or more of the maximum width Wh of the protrusion tip 126 in order to avoid current concentration. The outer shape of the cross section of the protruding portion 178 of the negative electrode 180 is also the same as the outer shape of the cross section of the protruding portion 128 of the positive electrode 130.

  In the comparison between the battery 100-3 and the battery 100 shown in FIG. 1, different portions are the shape of the protruding portion 128 of the positive electrode 130 and the shape of the protruding portion 178 of the negative electrode 180.

  Thus, even if the shape of the protrusion 128 of the positive electrode 130 and the shape of the protrusion 178 of the negative electrode 180 are curved and straight, the corners thereof are chamfered in a curve, so the protrusion tip 126 and the protrusion tip Concentration of current with the portion 176 can be avoided. Therefore, the battery 100-3 having a high capacity and a high output with improved energy density and output density can be provided.

[Modification of Embodiment 3]
FIG. 14 is a diagram illustrating a modification of the battery 100-3 according to the third embodiment. The configuration of battery 100A-3 according to this modification is the same as that of battery 100-3 shown in FIG. 13 except for the points described below.

  In the comparison between the battery 100A-3 according to the modification and the battery 100-3 shown in FIG. 13, the only different portions are the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

  That is, the size and shape of the protrusion 128 of the positive electrode 130 are different from the size and shape of the protrusion 178 of the negative electrode 180. Further, the shape of the protrusion tip portion 126 that forms the protrusion portion 128 of the positive electrode 130 is similar to the shape of the protrusion tip portion 176 that forms the protrusion portion 178 of the negative electrode 180.

  Comparing the shape of the protrusion tip portion 126 and the shape of the protrusion tip portion 176 in FIG. 14, it can be seen that the shapes are similar but the thicknesses are different. That is, it can be seen that the positive electrode 130 and the negative electrode 180 have an asymmetric shape.

  As described above, even if the positive electrode 130 and the negative electrode 180 have asymmetric shapes, the outer shape of the cross section of the protrusion 128 and the protrusion 178 includes a curved portion. Concentration of current flowing in and out of the portion 178 can be avoided. Therefore, the high-capacity and high-power battery 100A-3 with improved energy density and power density can be provided.

[Embodiment 4]
FIG. 15 is a cross-sectional view of the battery according to the fourth embodiment. The configuration of the battery 100-4 according to the fourth embodiment is the same as the configuration of the battery 100 illustrated in FIG. 1 except for the points described below.

  In the battery 100-4, the outer shape of the cross section of the protruding portion 128 when the protruding portion 128 of the positive electrode 130 is cut vertically along the direction in which the protruding portions 128 are arranged is only a straight line. Further, the corners of the outer shape of the cross section of the protrusion 128 are linearly chamfered in a range of at least 10% of the maximum width Wh of the protrusion tip 126 in order to avoid current concentration. The outer shape of the cross section of the protruding portion 178 of the negative electrode 180 is also the same as the outer shape of the cross section of the protruding portion 128 of the positive electrode 130.

  In the comparison between the battery 100-4 and the battery 100 shown in FIG. 1, the different portions are the shape of the protruding portion 128 of the positive electrode 130 and the shape of the protruding portion 178 of the negative electrode 180.

  As described above, even if the protrusions 128 of the positive electrode 130 and the protrusions 178 of the negative electrode 180 are only straight, the corners thereof are linearly chamfered, so that the protrusion tip 126 and the protrusion tip 176 Current concentration during the period can be relaxed. Therefore, the battery 100-4 having a high capacity and a high output with improved energy density and output density can be provided.

[Modification of Embodiment 4]
FIG. 16 is a diagram illustrating a modification of the battery 100-4 according to the fourth embodiment. The configuration of battery 100A-4 according to this modification is the same as that of battery 100-4 shown in FIG. 15 except for the points described below.

  In the comparison between the battery 100A-4 according to the modification and the battery 100-4 shown in FIG. 15, the only difference is the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

  That is, the size and shape of the protrusion 128 of the positive electrode 130 are different from the size and shape of the protrusion 178 of the negative electrode 180. Further, the shape of the protrusion tip portion 126 that forms the protrusion portion 128 of the positive electrode 130 is similar to the shape of the protrusion tip portion 176 that forms the protrusion portion 178 of the negative electrode 180.

  Comparing the shape of the protrusion tip portion 126 and the shape of the protrusion tip portion 176 in FIG. 16, it can be seen that the shapes are similar but the thicknesses are different. That is, it can be seen that the positive electrode 130 and the negative electrode 180 have an asymmetric shape.

  Thus, even if the positive electrode 130 and the negative electrode 180 have an asymmetric shape, the outer shape of the cross section of the protrusion 128 and the protrusion 178 includes a portion that is linearly chamfered. Concentration of current flowing in and out of the portion 128 and the protruding portion 178 can be reduced. Therefore, the high-capacity and high-power battery 100A-4 with improved energy density and power density can be provided.

[Embodiment 5]
FIG. 17 is a cross-sectional view of the battery according to the fifth embodiment. The configuration of the battery 100-5 according to the fifth embodiment is the same as the configuration of the battery 100 illustrated in FIG. 1 except for the points described below.

  In the battery 100-5, the outer shape of the cross section of the protrusion 128 when the protrusion 128 of the positive electrode 130 is cut vertically along the direction in which the protrusions 128 are arranged is only a straight line. The outer shape of the cross section of the protrusion 178 of the negative electrode 180 is also the same as the cross section of the protrusion 128 of the positive electrode 130.

  In the comparison between the battery 100-5 and the battery 100 shown in FIG. 1, the different portions are the shape of the protruding portion 128 of the positive electrode 130 and the shape of the protruding portion 178 of the negative electrode 180.

  Thus, even if the shape of the protrusions 128 of the positive electrode 130 and the protrusions 178 of the negative electrode 180 is only a straight line shape, the area of the protrusion 128 is increased, so the protrusion tip 126 and the protrusion tip 176 It is possible to alleviate the concentration of current between them. Therefore, a high-capacity, high-power battery 100-5 with improved energy density and power density can be provided.

[Modification of Embodiment 5]
FIG. 18 is a diagram illustrating a modified example of the battery 100-5 according to the fifth embodiment. The configuration of battery 100A-5 according to this modification is the same as the configuration of battery 100-5 shown in FIG. 17 except for the points described below.

  In the comparison between the battery 100A-5 according to the modification and the battery 100-5 shown in FIG. 17, the only different parts are the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180.

  That is, the size and shape of the protrusion 128 of the positive electrode 130 are different from the size and shape of the protrusion 178 of the negative electrode 180. Further, the shape of the protrusion tip portion 126 that forms the protrusion portion 128 of the positive electrode 130 is similar to the shape of the protrusion tip portion 176 that forms the protrusion portion 178 of the negative electrode 180.

  Comparing the shape of the protrusion tip portion 126 and the shape of the protrusion tip portion 176 in FIG. 18, it can be seen that the shapes are similar but the thicknesses are different. That is, it can be seen that the positive electrode 130 and the negative electrode 180 have an asymmetric shape.

  Thus, even if the positive electrode 130 and the negative electrode 180 have asymmetric shapes, the areas of the protrusions 128 and the protrusions 178 are large, so that the current flowing in and out of the protrusions 128 and the protrusions 178 is concentrated. Can be relaxed. Therefore, the high-capacity and high-power battery 100A-5 with improved energy density and power density can be provided.

  As described above, according to the batteries 100, 100A, 100-2, 100A-2, 100-3, 100A-3, 100-4, 100A-4, 100-5, and 100A-5 according to Embodiment 1-5. For example, the concentration of current flowing in and out between the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180 can be avoided. Therefore, a current flows uniformly between the positive electrode 130 and the negative electrode 180, and a high-capacity, high-power battery with improved energy density and output density can be provided. Further, since these batteries are manufactured by a 3D printer, there are no problems in productivity, reliability, and manufacturing.

(Comparison of Conventional Battery and Battery According to Embodiment 1-5)
Next, the reason why the battery according to Embodiment 1-5 can be a high-capacity and high-power battery although it has the same size as that of the conventional battery will be described in detail with reference to the drawings.

  FIG. 19 is a diagram for explaining a current density distribution between a positive electrode and a negative electrode of a conventional battery.

  The conventional battery shown in FIG. 19 has a comb shape in which both positive and negative electrodes repeat rectangular irregularities. In this battery, as shown in the figure, the current density distribution flowing in and out between both the positive electrode and the negative electrode is not uniform, and a portion with a coarse current density and a portion with a dense current density are mixed. Specifically, current concentrates at the corners and sharp corners of the protruding portions of the positive electrode and the negative electrode, and current does not flow so much in the flat portions of the positive electrode and the negative electrode. Thus, if there is a portion where the current density is not uniform, sufficient input / output characteristics as a battery cannot be obtained, and it is difficult to achieve a battery with high capacity and high output while aiming for miniaturization.

  For this reason, in the battery according to the embodiment, the portion where the current concentrates is eliminated by eliminating the acute angle portion from the shape of the positive and negative electrode protrusions and devising the shape of the protrusion. In the battery 100 according to the first embodiment, as illustrated in FIG. 1, the shapes of the protrusions 128 of the positive electrode 130 and the protrusions 178 of the negative electrode 180 are formed only by curves. Further, the shape is such that the dimension increases from the projecting column portions 124 and 174 toward the projecting tip portions 126 and 176 so that the contact area with the separator 150 increases. With these shapes, the movement distance of lithium ions between the protrusion 128 of the positive electrode 130 and the protrusion 178 of the negative electrode 180 is shortened.

FIG. 20 is a diagram illustrating simulation results of the conventional battery and the battery according to Embodiment 1. The simulation was performed for the electrolyte lithium potential distribution, current density distribution, and active material lithium concentration distribution between the positive electrode and the negative electrode. This simulation technique and simulation conditions are described in Graham M. et al. Goldin et al. Electrochimica Acta, 64, 118-129 (2012) [Literature 1] is used, and it is standardized based on the porous electrode theory. The analysis assumptions at that time are as follows.
・ Discharge analysis of 1C from SOC (charge rate) = 50%.
・ Ignore the effects of solid / solid interface resistance.
・ Ignore the effects of volume expansion and contraction.
・ Ignore the effect of heat loss due to overvoltage in an isothermal state.
• The electrode layer should be a uniform porous body (porosity and active material volume ratio are uniform and constant).
-Assume that the positive and negative electrodes have a symmetrical structure.
・ Ion transport in the electrolyte occurs only by conduction (there is no concentration gradient and the diffusion effect is ignored).
• The diffusion of lithium ions in the active material is sufficiently fast, and there is no concentration distribution between the electrolyte interface and the inside of the particles, and it is assumed to be uniform.

The basic formula used for the simulation is as follows.
(1) Active material potential distribution

(2) Li + concentration distribution in electrolyte

(3) Electrolyte potential distribution

(4) Electrode reaction (Butler-Volmer formula)

(5) Exchange current density

(6) Overvoltage (positive electrode, negative electrode)

[Document 2] K. Karthikeyan et al. , J .; Power Sources 185 1398 (2008),
[Document 3] describes A. M.M. Colglasure et al. Electrochim. Acta 55 8960 (2010).

The calculation conditions for the simulation are as follows.
・ Positive electrode: lithium cobaltate, negative electrode: graphite, electrolyte: solid electrolyte ・ Battery: 384 μm × 384 μm (48 mesh × 48 mesh)
・ 1 mesh: 8μm
-The ratio of the positive electrode, the negative electrode, and the electrolyte layer in the entire battery is equal to 1/3.
The electrode layer has a volume ratio of 0.5 for the active material, 0.3 for the electrolyte, and 0.2 for the electrolyte layer.
・ Effective ion conductivity and effective electron conductivity shall be 2.4 of the above volume ratio.

  In this simulation, the ion potential and electron potential distributions are obtained by convergence calculation based on the above basic equations, and then the concentration distribution in the active material is calculated at each time step. By repeating this every time step, the time change of the state inside the battery is calculated.

  The results of simulating the conventional battery and the battery according to Embodiment 1 by the above simulation method and simulation conditions are as shown in FIG.

  When the electrolyte lithium potential distribution between the positive electrode and the negative electrode when discharging from SOC = 50% to 1C is simulated, the battery 100 according to the first embodiment has the electrolyte lithium potential between the positive electrode and the negative electrode. It can be seen that the distribution is uniform. On the other hand, in the conventional battery, the electrolyte lithium potential distribution between the positive electrode and the negative electrode is not uniform, and in particular, the electrolyte lithium potential distribution at the corner of the tip of the comb-shaped electrode is clearly non-uniform. I understand.

  Moreover, when the current density distribution between the positive electrode and the negative electrode when discharging from SOC = 50% to 1C is simulated, the battery 100 according to Embodiment 1 has a current density distribution between the positive electrode and the negative electrode. It turns out that it is uniform. On the other hand, it can be seen that in the conventional battery, the potential distribution between the positive electrode and the negative electrode is not uniform, and in particular, the current density distribution at the tip of the comb-shaped electrode is clearly high.

  Furthermore, when the active material lithium concentration distribution between the positive electrode and the negative electrode when discharging from SOC = 50% to 1C is simulated, the battery 100 according to Embodiment 1 has an active material between the positive electrode and the negative electrode. It can be seen that the lithium concentration distribution is uniform. On the other hand, in the conventional battery, the active material lithium concentration distribution between the positive electrode and the negative electrode is not uniform, and in particular, the active material lithium concentration distribution at the tip of the comb-shaped electrode is not uniform.

  As shown in the above simulation results, the battery 100 according to the first embodiment clearly has an electrolyte lithium potential distribution, a current density distribution, an active material between the positive electrode and the negative electrode as compared with the conventional battery. The lithium concentration distribution is uniform.

  The reason is considered as follows. In the conventional battery, since the positive electrode and the negative electrode are comb-shaped, the capacity between the positive and negative electrodes is unbalanced at the tip of the protrusion, the electrical resistance of the tip is high at the tip, and at the tip There are factors that induce non-uniformity, such as a long ion movement distance. On the other hand, in the battery 100 according to the first embodiment, since the positive electrode and the negative electrode are spherical, there is no cause of inhomogeneity as described above. This is the reason for the simulation results.

  Although the simulation is performed for the battery 100 according to the first embodiment, all types of batteries 100A, 100-2, 100A-2, 100-3, 100A-3, 100-4 according to the first to fifth embodiments are performed. , 100A-4, 100-5, and 100A-5 are not significantly different from the simulation results of the battery 100 according to the first embodiment.

  FIG. 21 is a graph showing SOC-voltage characteristics (1C) of the conventional battery and the battery according to Embodiment 1. FIG. 22 is a graph showing SOC-voltage characteristics (5C) of the conventional battery and the battery according to Embodiment 1. Here, the SOC is the ratio of the current remaining battery capacity when the full charge is 1, and means the battery charge rate. For example, if the current remaining battery capacity is half of full charge, the SOC is 0.5.

  FIG. 21 shows how the voltage is changed when the battery 100 according to the first embodiment having a conventional electrode having a comb-shaped electrode and the spherical electrode discharges 1 C from a fully charged state (charge rate: 1.0). It shows whether it falls. FIG. 22 shows how the voltage decreases when 5 C is discharged from a fully charged state (charge rate: 1.0).

  First, when discharging 1 C with a conventional battery, the voltage decreases with a decrease in SOC, and the voltage that was 4.0 V when SOC is 1.0 is decreased to about 3.05 V with SOC 0.2. . Similarly, when the battery 100 according to the first embodiment discharges 1 C, the voltage decreases as the SOC decreases, as in the conventional battery, but the degree of the decrease is slower than that of the conventional battery. . In the battery 100 according to the first embodiment, the voltage which was 4.0 V when the SOC is 1.0 is reduced only to about 3.5 V even when the SOC is 0.2.

  In addition, when 5C is discharged with a conventional battery, the voltage rapidly decreases as the SOC decreases, and the voltage that was 4.0V at SOC 1.0 decreases to about 3.15V at SOC 0.8. ing. Similarly, when the battery 100 according to Embodiment 1 is discharged at 5 C, the voltage rapidly decreases as the SOC decreases, as in the conventional battery, but the degree of the decrease is slower than in the conventional battery. It is. In the battery 100 according to the first embodiment, the voltage which was 4.0 V when the SOC is 1.0 is reduced only to about 3.6 V even when the SOC is 0.2.

  From these graphs, it is clear that the battery 100 according to Embodiment 1 in which the voltage drop is slow is superior to the conventional battery in terms of battery performance.

  FIG. 23 is a graph showing DOD-discharge rate characteristics of the conventional battery and the battery according to Embodiment 1. Here, DOD (depth of discharge) refers to the ratio of the discharge amount to the discharge capacity of the battery. For example, if a battery having a discharge capacity of 1000 mAh is discharged at 700 mAh, the depth of discharge is 70%. The discharge rate is a relative ratio of current during discharge to battery capacity. For example, a discharge rate of 1C is a current value at which a battery having a nominal capacity is discharged at a constant current and discharge is completed in exactly one hour. A battery having a rated capacity of 10 Ah has a discharge rate of 1C. Sometimes 10A, and 10C, 100A.

  As shown in the graph of FIG. 23, compared to the conventional battery, the battery 100 according to the first embodiment has a large DOD value over the range of all discharge rates. That is, the battery 100 according to the first embodiment can maintain a large charging rate even when a large current is output. For this reason, the battery 100 according to the first embodiment is improved in the energy density of the battery and the output density of the battery, and thus has a high capacity and a high output.

  This is because the current density between the positive and negative electrodes is uniform, and it can be expected to improve the durability of the charge / discharge cycle. This means that all types of batteries 100A, 100-2, 100A-2, 100-3, 100A-3, 100-4, and 100A-4 according to the first to fifth embodiments except the battery 100 according to the first embodiment. , 100-5, 100A-5.

  As described above, the batteries 100, 100A, 100-2, 100A-2, 100-3, 100A-3, 100-4, 100A-4, 100-5, and 100A-5 according to Embodiment 1-5 are used. According to this, since the current flows uniformly between the positive and negative electrodes, it is possible to obtain a high capacity and high output battery in which the energy density of the battery and the output density of the battery are improved.

  The embodiment of the electrode according to the present invention, the battery using the electrode, and the method for manufacturing the battery has been described above, but the technical scope of the present invention is not limited to the above-described embodiment, and the present invention is not limited thereto. Various forms may be adopted within the technical scope of the present invention.

100, 100A, 100-2, 100A-2, 100-3, 100A-3, 100-4, 100A-4, 100-5, 100A-5 batteries,
110 positive electrode current collector,
120 positive electrode,
122, 172 Foundation part,
124, 174 Protruding struts,
126, 176 The tip of the protrusion,
128, 178 protrusion,
130 positive electrode,
150 separator,
160 negative electrode current collector,
170 negative electrode,
180 Negative electrode.

Claims (13)

A base portion, and a plurality of protrusions protruding from the base portion arranged at intervals from each other,
Each of the protrusions is
A protruding support column projecting from the base,
A protrusion tip portion protruding from the protrusion support portion, and
The electrode characterized in that the maximum width of the protrusion tip in the direction in which the protrusions are arranged is larger than the minimum width of the protrusion support.   2. The cross-sectional area of the protrusion tip portion when the protrusion is cut vertically along the direction in which the protrusions are arranged is larger than the cross-sectional area of the protrusion support portion. Electrodes.   The outer shape of the cross section of the protrusion when the protrusion is cut vertically along the direction in which the protrusions are arranged is formed only by a curve. electrode.   The outer shape of the cross section of the protrusion when the protrusion is cut vertically along the direction in which the protrusions are arranged is formed with a curve and a straight line. Electrode.   5. The electrode according to claim 4, wherein corners of the outer shape of the cross-section of the protrusion are chamfered in a curved line within a range of at least 10% of the maximum width of the protrusion tip.   The outer shape of the cross section of the protrusion when the protrusion is cut vertically along the direction in which the protrusions are arranged is formed only by a straight line. electrode.   7. The electrode according to claim 6, wherein a corner of the outer shape of the cross section of the protrusion is linearly chamfered in a range of at least 10% of the maximum width of the protrusion tip.   The electrode according to claim 1, wherein the protrusion extends in a direction intersecting with a direction in which the protrusions are arranged. The electrode according to any one of claims 1 to 8 as a positive electrode and a negative electrode,
The battery is characterized in that the negative electrode protrusion is positioned between the adjacent protrusions of the positive electrode, and a separator is interposed between the positive electrode protrusion and the negative electrode protrusion.   The battery according to claim 9, wherein the size and shape of the positive electrode protrusion are the same as the size and shape of the negative electrode protrusion.   10. The battery according to claim 9, wherein the size and shape of the protrusion of the positive electrode are different from the size and shape of the protrusion of the negative electrode.   The battery according to claim 11, wherein a shape of a protrusion tip portion forming the protrusion portion of the positive electrode is similar to a shape of the protrusion tip portion forming the protrusion portion of the negative electrode. A method for producing a battery according to any one of claims 9 to 12,
With 3D printer
Forming a base part of the positive electrode or the negative electrode;
Alternately forming positive or negative projection protrusions and separators;
A step of repeatedly forming a protruding column part of a positive electrode or a negative electrode, a separator, a protruding tip part of a negative electrode or a positive electrode, and a separator;
A step of repeatedly forming a positive or negative projection tip, a separator, a negative or positive projection post, and a separator;
Alternately forming negative or positive electrode protrusion struts and separators;
Forming a negative electrode or positive electrode base, and
A battery manufacturing method comprising manufacturing a battery by carrying out