Battery

Abstract

A battery according to the present disclosure comprises: a first battery element; a second battery element that is stacked on the first battery element and is electrically connected in parallel with the first battery element; and a first lead terminal that is arranged between the first battery element and the second battery element and is electrically connected to the first battery element and the second battery element, the first lead terminal having a contact part that contacts at least one element selected from the group consisting of the first battery element and the second battery element, and a non-contact part that does not contact one of the first battery element or the second battery element, the non-contact part having a first embossed form on at least a part of the surface thereof.

Description

[Technical Field]

[0001] This disclosure relates to batteries. [Background technology]

[0002] Patent Document 1 discloses a battery in which a voltage detection terminal is connected to a current collector.

[0003] Patent document 2 discloses an energy storage device comprising a current collector having a plurality of grooves formed therein. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-70989 [Patent Document 2] International Publication No. 2010 / 116872 [Overview of the project] [Problems that the invention aims to solve]

[0005] The purpose of this disclosure is to provide a battery with improved reliability. [Means for solving the problem]

[0006] The battery disclosed herein is First battery element, A second battery element is stacked on the first battery element and electrically connected in parallel with the first battery element, A first lead terminal is positioned between the first battery element and the second battery element and is electrically connected to the first battery element and the second battery element, Equipped with, The first lead terminal has a contact portion that contacts at least one selected from the group consisting of the first battery element and the second battery element, and a non-contact portion that does not contact either the first battery element or the second battery element. The non-contact portion has a first embossed shape on at least a part of its surface.

Advantages of the Invention

[0007] The present disclosure provides a battery with improved reliability.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1000 according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view and a plan view showing a schematic configuration of an embossed pattern of the battery 1000 according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1100 according to the second embodiment. [Figure 4] FIG. 4 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1200 according to the third embodiment. [Figure 5] FIG. 5 is a plan view showing a schematic configuration of an outer edge and an embossed pattern of the battery 1200 according to the third embodiment. [Figure 6] FIG. 6 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1300 according to the fourth embodiment. [Figure 7] FIG. 7 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1400 according to the fifth embodiment. [Figure 8] FIG. 8 is a cross-sectional view and a plan view showing a schematic configuration of a battery 1500 according to the sixth embodiment.

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be specifically described while referring to the drawings.

[0010] The embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, arrangement positions and connection forms of components, manufacturing processes, the order of manufacturing processes, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] In this specification, terms indicating the relationship between elements such as parallel, terms indicating the shape of elements such as rectangular parallelepipeds, and numerical ranges are not expressions representing only strict meanings, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0012] Each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, the scales etc. in each figure do not necessarily match. Also, in each figure, the same reference numerals are assigned to substantially the same configurations, and overlapping descriptions are omitted or simplified.

[0013] In this specification and the drawings, the x-axis, y-axis, and z-axis indicate the three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the z-axis direction is taken as the thickness direction of the battery. Also, in this specification, unless otherwise specified, the "thickness direction" means the direction perpendicular to the plane on which each layer in the battery and battery element is laminated.

[0014] In this specification, unless otherwise specified, "plan view" means the case of viewing the battery along the lamination direction of the battery element. In this specification, unless otherwise specified, "thickness" means the length in the lamination direction of the battery, battery element, and each layer.

[0015] In this specification, unless otherwise specified, in the battery and battery element, "side surface" means the surface along the lamination direction of the battery element, and "main surface" means the surface other than the side surface.

[0016] In this specification, "inner" and "outer" in "inner side" and "outer side", etc. mean that when viewing the battery along the lamination direction of the battery element, the center side of the battery is "inner" and the peripheral side of the battery is "outer".

[0017] In this specification, the terms "upper" and "lower" in the battery configuration do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial perception, but rather to terms defined by the relative positional relationship based on the stacking order in the stacked configuration. Furthermore, the terms "upper" and "lower" apply not only when two components are spaced apart and another component exists between them, but also when two components are placed in close proximity and touching each other.

[0018] (First Embodiment) The following describes a battery according to the first embodiment.

[0019] The battery according to the first embodiment comprises a first battery element, a second battery element, and a first lead terminal. The second battery element is stacked on the first battery element and electrically connected in parallel with the first battery element. The first lead terminal is positioned between the first battery element and the second battery element and is electrically connected to both the first and second battery elements. The first lead terminal has a contact portion that contacts at least one selected from the group consisting of the first and second battery elements, and a non-contact portion that does not contact either the first or second battery element. The non-contact portion of the first lead terminal has a first embossed shape on at least a part of its surface. In other words, the non-contact portion of the first lead terminal can also be described as an exposed portion that protrudes outward from the side surface of the stack of the first and second battery elements. Hereinafter, the side surface of the stack of the first and second battery elements may be referred to as the "battery element side surface."

[0020] In this specification, the first embossed shape provided on at least a portion of the surface of the first lead terminal means a shape formed by at least one of a convex shape and a concave shape from the surface of the first lead terminal. That is, the first embossed shape may be formed by a convex shape formed on the surface of the first lead terminal, or by a concave shape, or by both a convex shape and a concave shape (i.e., a concave-convex shape). Note that both single-sided embossing and double-sided embossing exist, and the embossed shape in this disclosure may be either.

[0021] With the above configuration, even if stress such as shock or vibration is applied to the battery, the effect of the stress on the routing portion of the first lead terminal (i.e., the non-contact portion) can be absorbed and dispersed by the first embossed shape. As a result, for example, the fracture of the first lead terminal due to the formation of a point of origin of damage on the outer edge of the routing portion of the first lead terminal can be suppressed. Therefore, the occurrence of circuit breaks (i.e., open faults) caused by damage to the lead terminal can be reduced. Accordingly, with the battery configuration of the first embodiment, even a multilayer battery in which multiple thin and large battery cells are stacked can have high reliability and a large capacity.

[0022] As described in the [Background Technology] section, Patent Document 1 discloses a battery in which a voltage detection terminal is connected to a current collector. However, this battery has a recess that communicates with the current collector, and the voltage detection terminal is connected by contacting this recess. For this reason, in the battery disclosed in Patent Document 1, the recess is located at the connection point between the voltage detection terminal and the current collector, that is, at the contact point between the voltage detection terminal and the current collector. Therefore, the battery disclosed in Patent Document 1 is not a battery in which, like the battery according to the first embodiment, the non-contact portion (i.e., exposed portion) of the first lead terminal that does not contact either the first battery element or the second battery element has irregularities, i.e., an embossed shape.

[0023] Patent Document 2 discloses an energy storage device comprising a current collector having multiple grooves formed therein. This configuration aims to reduce the resistance at the contact point between the electrode layer containing the active material and the current collector. Therefore, the grooves are not provided in the non-contact portion (i.e., the exposed portion) of the lead terminal. Consequently, in the energy storage device of Patent Document 2, the grooves provided at the connection point between the electrode layer and the current collector do not have the effect of suppressing damage to the lead terminal, as in the battery according to the first embodiment.

[0024] Figure 1 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1000 according to the first embodiment.

[0025] Figure 1(a) shows a cross-sectional view of the battery 1000 according to the first embodiment. Figure 1(b) is a plan view of the battery 1000 according to the first embodiment, viewed from the positive side in the z-axis direction. Figure 1(a) shows a cross-section at the position indicated by line II in Figure 1(b).

[0026] As shown in Figure 1, the battery 1000 comprises a first battery element 400, a second battery element 500, and a first lead terminal 600. The first battery element 400 and the second battery element 500 are stacked on top of each other and electrically connected in parallel. The first lead terminal 600 is positioned between the first battery element 400 and the second battery element 500 and is electrically connected to both the first battery element 400 and the second battery element 500. The battery 1000 according to the first embodiment further comprises, for example, a second lead terminal 700 electrically connected to the first battery element 400 and a third lead terminal 800 electrically connected to the second battery element 500. In other words, the battery 1000 has, for example, a second lead terminal 700, a first battery element 400, a first lead terminal 600, a second battery element 500, and a third lead terminal 800, arranged in this order in the stacking direction between the first battery element 400 and the second battery element 500.

[0027] As shown in Figure 1(b), the first lead terminal 600 has a first embossed shape on at least a portion of the non-contact area that does not come into contact with either the first battery element 400 or the second battery element 500. In Figure 1(b), the first embossed shape is represented by hatching on the first lead terminal 600. In the battery 1000 according to the first embodiment, the first embossed shape is provided, for example, on almost the entire non-contact area of ​​the first lead terminal 600.

[0028] With the above configuration, even if stress such as shock or vibration is applied to the battery 1000, the effect of the stress on the non-contact portion, which is the routing portion of the first lead terminal 600, can be absorbed and dispersed by the first embossed shape. As a result, for example, the fracture of the first lead terminal 600 due to the formation of a point of origin of damage on the outer edge of the routing portion of the first lead terminal 600 can be suppressed. Therefore, the occurrence of circuit breakage caused by damage to the lead terminal can be reduced. Consequently, the battery 1000 can have high reliability and a large capacity.

[0029] As described above, battery 1000 is a stacked battery in which two battery elements are connected in parallel.

[0030] The first battery element 400 and the second battery element 500 are, for example, solid-state batteries. That is, the battery 1000 may be an all-solid-state battery. When the first battery element 400 and the second battery element 500 are solid-state batteries, the first lead terminal 600 is fixed between the first battery element 400 and the second battery element 500, making it more susceptible to damage from stress such as shock or vibration. However, in the battery 1000 according to the first embodiment, the non-contact portion of the first lead terminal 600 has a first embossed shape on at least a part of its surface, so even if the battery 1000 is an all-solid-state battery, damage to the first lead terminal 600 is less likely to occur.

[0031] As shown in Figure 1(b), the second lead terminal 700, like the first lead terminal 600, may have a first embossed shape on at least a portion of the non-contact portion that is not in contact with the battery element, i.e., in the case of the battery 1000, not in contact with the first battery element 400. In particular, the first embossed shape may be provided on the portion of the non-contact portion of the second lead terminal 700 that protrudes outward from the side surface of the battery element. By having the first embossed shape configured as described above, the second lead terminal 700 can be prevented from breaking even when stress such as shock or vibration is applied to the battery 1000, similar to the first lead terminal 600. Note that in Figure 1(b), the first embossed shape provided on the second lead terminal 700 is represented by hatching on the second lead terminal 700.

[0032] As shown in Figure 1(b), the third lead terminal 800, like the first lead terminal 600, may have a first embossed shape on at least a portion of the non-contact portion that is not in contact with the battery element, i.e., in the case of the battery 1000, not in contact with the second battery element 500. The first embossed shape may be provided on the non-contact portion of the second lead terminal 700, in particular, on the portion that protrudes outward from the side surface of the battery element. By having the third lead terminal 800 have the first embossed shape configured as described above, the fracture of the third lead terminal 800 can be suppressed even when stress such as shock or vibration is applied to the battery 1000, similar to the first lead terminal 600.

[0033] The first battery element 400 comprises a first electrode 100, a solid electrolyte layer 300, and a second electrode 200 in this order. The first electrode 100 includes a first current collector 110 and a first active material layer 120. The second electrode 200 includes a second current collector 210 and a second active material layer 220.

[0034] The second battery element 500, like the first battery element 400, comprises a first electrode 100, a solid electrolyte layer 300, and a second electrode 200 in that order. Similar to the first battery element 400, in the second battery element 500, the first electrode 100 includes a first current collector 110 and a first active material layer 120, and the second electrode 200 includes a second current collector 210 and a second active material layer 220. The first electrode 100 of the second battery element 500 has the same polarity as the first electrode 100 of the first battery element 400. The second electrode 200 of the second battery element 500 has the same polarity as the second electrode 200 of the first battery element 400.

[0035] As shown in Figure 1(a), the first battery element 400 is stacked on the second battery element 500 such that the second current collector 210 of the first battery element 400 faces the second current collector 210 of the second battery element 500. Alternatively, the first battery element 400 may be stacked on the second battery element 500 such that the first current collector 110 of the first battery element 400 faces the first current collector 110 of the second battery element 500. In other words, the first battery element 400 and the second battery element 500 only need to be stacked in an electrically parallel connection, and their orientation is not limited to the orientation shown in Figure 1(a).

[0036] Between the first battery element 400 and the second battery element 500, in addition to the first lead terminal 600, another conductive layer 900 may be placed, for example.

[0037] Only the first lead terminal 600 may be placed between the first battery element 400 and the second battery element 500.

[0038] The first electrode 100 may be the positive electrode and the second electrode 200 may be the negative electrode. In this case, the first current collector 110 and the first active material layer 120 are the positive electrode current collector and the positive electrode active material layer, respectively. The second current collector 210 and the second active material layer 220 are the negative electrode current collector and the negative electrode active material layer, respectively.

[0039] Hereinafter, the first current collector 110 and the second current collector 210 may be collectively referred to simply as "current collectors." The first active material layer 120 and the second active material layer 220 may be collectively referred to simply as "active material layers." The first lead terminal 600, the second lead terminal 700, and the third lead terminal 800 may be collectively referred to simply as "lead terminals."

[0040] In Figure 1, the first battery element 400 and the second battery element 500 are flattened rectangular parallelepipeds.

[0041] In Figure 1, the first lead terminal 600 is positioned between the first battery element 400 and the second battery element 500. If a conductive layer 900 is provided, the conductive layer 900 is also positioned between the first battery element 400 and the second battery element 500, similar to the first lead terminal 600.

[0042] The conductive layer 900 is formed of a conductive material. This conductive material includes a conductor. The conductive material may also be a conductive resin material. The conductive resin material may, for example, include conductive particles. The conductive particles are, for example, powders such as Ag or Cu.

[0043] The second lead terminal 700 and the third lead terminal 800 are connected to the upper and lower main surfaces of the battery 1000 by, for example, a conductive material. In the battery 1000 shown in Figure 1, the second lead terminal 700 is electrically connected to an electrode of a different pole than the electrode to which the first lead terminal 600 is electrically connected in the first battery element 400. The third lead terminal 800 is electrically connected to an electrode of a different pole than the electrode to which the first lead terminal 600 is electrically connected in the second battery element 500.

[0044] The shape of the lead terminals may be, for example, foil-like, plate-like, or mesh-like. The first lead terminal 600 has an embossed shape on the portion exposed from the first battery element 400 and the second battery element 500. That is, the first lead terminal 600 has an embossed shape in the non-contact portion that is not in contact with the first battery element 400 and the second battery element 500.

[0045] The second lead terminal 700 may have the same shape as the third lead terminal 800. This allows for stress distribution when an impact or other force is applied, as a similar load is applied to both lead terminals. As a result, damage to the lead terminals is suppressed. Furthermore, since the electrical resistance of the lead ends of the same poles is the same, the heat generated at high currents will also be similar. Therefore, local differences in battery operation due to temperature differences are reduced, suppressing performance degradation and resulting in high reliability.

[0046] The lead terminal material only needs to be conductive. Examples of such materials include stainless steel, nickel (Ni), aluminum (Al), iron (Fe), titanium (Ti), copper (Cu), palladium (Pd), gold (Au), platinum (Pt), or alloys of two or more of these. The lead terminal material should be appropriately selected considering the operating potential and conductivity of the battery 1000. It may also be selected according to the required tensile strength or heat resistance. The lead terminal may be made of high-strength electrolytic copper foil or a clad material formed by laminating dissimilar metal foils. The surface of the lead terminal may be plated with a conductor such as Ni, Cu, or Sn.

[0047] The first embossed shape of the lead terminal may be, for example, a surface with a maximum height roughness Rz (JIS B 0601:2013) approximately equal to the thickness of the lead terminal. For example, if the first lead terminal 600 is a Cu foil with a thickness of 10 μm to 15 μm, the first embossed shape provided on the first lead terminal 600 may consist of a surface with a maximum height roughness Rz of, for example, 10 μm to 15 μm.

[0048] The first embossed shape provided on the lead terminal may have a periodic structure in which embossed unit shapes are repeatedly arranged at predetermined intervals. Hereinafter, an embossed shape having a periodic structure in which embossed unit shapes are repeatedly arranged at predetermined intervals may be referred to as an "embossed pattern." The embossed pattern allows localized stress concentration on the lead terminal to be dispersed and absorbed over a wide area where the periodic structure is provided. For example, the linear fracture that is a common fracture mode of lead terminals can be divided by the periodic structure of the emboss, which is made up of multiple embossed unit shapes (e.g., unit concave shapes or unit convex shapes), thereby suppressing the progression of damage. As a result, the battery 1000 can suppress the fracture of the first lead terminal 600, and as a result, the occurrence of circuit disconnection can be suppressed. Furthermore, the shape retention of the lead terminal due to stress is improved by the provision of the embossed pattern, making it more resistant to deformation than in a smooth foil-like state (i.e., a thin plate-like state without an embossed shape). Therefore, deformation of the lead terminals is suppressed, and for example, metal fatigue of the metal materials constituting the lead terminals is reduced. As a result, the lead terminals become less prone to damage.

[0049] The first embossed shape may be, for example, an embossed pattern in which the embossed unit shape is a unit concave shape. The embossed pattern may have a periodic structure in which, for example, a unit concave shape that is a 100 μm × 100 μm square and has a thickness (i.e., a concave depth) of 10 μm is arranged at intervals of 50 μm (i.e., at a pitch of 50 μm). A schematic diagram of an example of such a shape is shown in Figure 2. Figure 2 is a cross-sectional view and a plan view showing the schematic configuration of the embossed pattern of the battery 1000 according to the first embodiment.

[0050] Figure 2(a) is a plan view showing a schematic configuration of an example of the embossed pattern of battery 1000 according to the first embodiment. Figure 2(b) is a cross-sectional view showing a schematic configuration of an example of the embossed pattern of battery 1000 according to the first embodiment.

[0051] The corners 1a of the unit concave shape 1 may be smoothly curved. In other words, the corners of the unit concave shape 1 do not have to be sharp.

[0052] The depth of the unit concave shape 1 may be set to an embossed thickness greater than or equal to the average thickness of the lead terminal (i.e., about 1.5 times or more the thickness variation), taking into account, for example, when the thickness variation of the lead terminal is typically around ±30% (i.e., the difference between the maximum thickness (i.e., +30% thickness) and the minimum thickness (i.e., -30% thickness) = about 60% of the thickness). This ensures that a significant effect of the embossed shape is obtained without being absorbed by the thickness variation. Furthermore, the smaller the pitch (spacing) of the arrangement of the unit concave shape 1 in the embossed pattern, the greater the elasticity of the lead terminal. Therefore, the smaller the pitch of the arrangement of the unit concave shape 1, the better the stress resistance and heat dissipation of the lead terminal. Depending on the processability of the conductive material constituting the lead terminal, the thickness level of the conductive material may be set as the upper limit of the arrangement pitch. For example, in the case of a general thin layer of Cu current collector foil, the pitch may be about 10 μm or less.

[0053] As described above, by providing the first embossed shape to the lead terminal, fracture of the lead terminal due to stress and impact can be suppressed. In addition to making the lead terminal less susceptible to damage due to the first embossed shape, the uneven surface also provides elasticity against stress, so the stress can be absorbed by the overall elasticity of the lead terminal. Therefore, it is preferable to have a pattern, arrangement, and pitch of the uneven surface that maximizes elasticity. The elasticity characteristics of the lead terminal can be evaluated by a general tensile test that measures displacement under tensile stress.

[0054] The embossing unit shapes that make up the embossed pattern are not limited to the shapes shown in Figure 2, and grid patterns, hexagonal shapes, or circular shapes may be used. The embossing unit shapes may be single-sided embossing or double-sided embossing.

[0055] If the first embossed shape has a periodic structure, the periodic structure may have a configuration in which multiple embossed unit shapes are arranged at intervals greater than or equal to the thickness of the first lead terminal 600. This forms a periodic structure on the surface of the lead terminal in which embossed unit shapes are repeatedly arranged at intervals greater than or equal to the variation in the thickness of a commonly used lead terminal (for example, the thickness of a Cu current collector foil). As a result, stress concentrated in the thin parts of the lead terminal can be dispersed and absorbed by the periodic structure of the first embossed shape. Therefore, damage due to stress such as shock and vibration can be suppressed. The periodic structure may have intervals of 10 μm or more.

[0056] The first embossed shape may include multiple linear embossed shapes. These multiple linear embossed shapes may or may not be parallel to each other. For example, the first embossed shape may be a shape in which multiple straight lines are arranged in parallel (a line shape). By arranging the linear embossed shapes to divide the line along which fracture progresses, the progression of fracture can be suppressed. In this case, it is desirable that the direction in which the linear embossed shapes extend is not parallel to the direction in which the outer edge of the battery 1000 extends. That is, the embossed shape may include linear embossed shapes that are not parallel to, i.e., intersect with, the direction in which the outer edges of the first battery element 400 and the second battery element 500 extend in a plan view. As a result, the linear embossed shapes divide the direction in which lead terminal damage is likely to occur in a line shape, thereby improving the stress resistance of the lead terminals. In particular, by arranging the linear embossed shape perpendicular to the direction in which the outer edges of the first battery element 400 and the second battery element 500 extend, the lead terminals become resistant to stress in the direction along the outer edges of the first battery element 400 and the second battery element 500. The linear embossed shape may also be arranged obliquely to the direction in which the outer edges of the first battery element 400 and the second battery element 500 extend.

[0057] A linear embossed shape may be formed by linear concave (groove-like) or linear convex shapes, or by embossed unit shapes being arranged in a linear pattern.

[0058] If not only the first lead terminal 600 but also the second lead terminal 700 and the third lead terminal 800 have the first embossed shape, the structure of the first embossed shape may be the same for all lead terminals or may be different from each other. Similar to the first lead terminal 600, the second lead terminal 700 and the third lead terminal 800 can also have their resistance to stresses such as tensile stress improved.

[0059] The first embossed shape may be placed on the outer edge of the lead terminal. The outer edge of the lead terminal is prone to becoming a point of origin for damage. Therefore, by having the above configuration, the progression of damage to the lead terminal can be suppressed. For example, the outer edge of the lead terminal has burrs or scratches formed during processing such as die stamping, making it prone to becoming a point of origin for damage. By providing the first embossed shape on such an outer edge, damage to the lead terminal caused by burrs or scratches can be reduced.

[0060] The first embossed shape may be positioned along the longer side of the outer edge of the lead terminal in a plan view. This protects the portion of the outer edge along the longer side, which is prone to damage.

[0061] As shown in Figure 1(b), the first battery element 400 and the second battery element 500 have a rectangular outer shape consisting of, for example, four sides in a plan view. For example, the approximate outer dimensions of the first battery element 400 and the second battery element 500 may be approximately 120 mm on the long side × 90 mm on the short side × 200 μm in thickness, respectively. The lead terminals may be extended with a width of, for example, 15 mm, and in this case, the thickness of the lead terminals may be, for example, 10 μm.

[0062] As shown in Figure 1(b), the first embossed shape is provided on the non-contact portion of the first lead terminal 600, but is not limited to this. For example, the first embossed shape may be provided only on the outer edge of the non-contact portion, i.e., the part that is prone to starting damage. This can enhance the effect of suppressing damage to the first lead terminal 600. In particular, the lead portion of the first lead terminal 600 that is drawn out from the side of the battery element (i.e., the part immediately after being drawn out from the battery element) is susceptible to damage because of the strong deformation stress from bending caused by the hard side. Therefore, in order to further suppress damage to the first lead terminal 600, the first embossed shape may be provided around the lead portion of the first lead terminal 600 that is drawn out from the side of the battery 1000. Furthermore, an embossed shape may be provided not only on the outer edge around the lead-out portion of the first lead terminal 600 (i.e., the part that is likely to be the starting point of damage), but also on the contact portion of the first lead terminal 600 along the side surface of the battery element (i.e., the part where damage progresses). In other words, with respect to the part of the first lead terminal 600 along the side surface of the battery element, an embossed shape may be provided up to the portion where the first lead terminal 600 is in contact with the first battery element 400 and / or the second battery element 500. This allows for selective protection of the starting point of damage and the area where damage is likely to occur for the first lead terminal 600. Needless to say, if the first embossed shape is provided on the entire surface of the non-contact portion of the first lead terminal 600, the effect of protecting the starting point of damage and the area where damage is likely to occur can be obtained. The same effect of such a first embossed shape applies to the second lead terminal 700 and the third lead terminal 800.

[0063] The embossed shape increases the surface area of ​​the lead terminals, thus providing a heat dissipation effect through the lead terminals. Therefore, it is possible to suppress the degradation of battery characteristics during high-temperature operation. To enhance the heat dissipation effect, the material of the lead terminals may have a high thermal conductivity. The surface area of ​​the lead terminals can also be increased and heat dissipation improved by making the irregularities of the embossed shape larger and the pitch of the embossed pattern smaller.

[0064] The following describes the specific configuration of the battery 1000.

[0065] As shown in Figure 1, the first lead terminal 600 extends from the side surface between the first battery element 400 and the second battery element 500 and is exposed. The first lead terminal 600 is a continuous, integral part of, for example, a plate-shaped conductive material (for example, a conductive foil having a thickness of approximately 10 μm to 16 μm). For example, a Cu foil may be used as the conductive foil. The conductive layer 900 and the first lead terminal 600 may be made of a continuous, integral member. With such an integral configuration, the flatness of the bonding surface can be ensured more effectively than if the first lead terminal 600 were partially inserted into the bonding surface between the first battery element 400 and the second battery element 500. As a result, the bonding performance between the first battery element 400 and the second battery element 500 is improved, and structural defects such as interfacial delamination between the battery elements can be suppressed. Furthermore, the tensile strength of the first lead terminal 600 can also be improved with the above-described integral configuration. Furthermore, the integrated structure suppresses the thermal resistance between the conductive layer 900 and the first lead terminal 600 (i.e., reduces the increase in resistance loss due to discontinuities), thus improving the heat dissipation effect during charging and discharging operations.

[0066] The embossed shape provided on the lead terminal may be formed by pressing a mold onto a predetermined location on a plate-shaped conductive material to create irregularities on the surface of the material. Alternatively, an embossed pattern may be formed on at least a portion of the surface of the lead terminal by periodically arranging embossed unit shapes of unit concave or convex shapes, that is, by repeatedly arranging embossed unit shapes at predetermined intervals. As described above, the embossed pattern may have a periodic structure in which, for example, unit concave shapes that are 100 μm × 100 μm squares and have a thickness (i.e., a recess depth) of 10 μm are arranged at intervals of 50 μm (i.e., at a pitch of 50 μm).

[0067] The lead terminals can be any conductor, and those with high conductivity are particularly preferred. Furthermore, metals with excellent processability and good plastic deformation properties are preferable. The lead terminals may also be made of the same material as the current collector that constitutes the battery element. This results in the lead terminals and the current collector having the same coefficient of thermal expansion, improving thermal shock resistance and potentially suppressing structural defects such as delamination.

[0068] The first battery element 400 and the second battery element 500 may be laminated together by joining the upper and lower main surfaces of a plate-shaped conductive material, such as Cu foil, which constitutes the conductive layer 900 and the first lead terminal 600, to each other using a conductive resin. For example, the conductive resin can be a thermosetting resin containing conductive particles of a highly conductive metal. Alternatively, the elements may be joined by melting solder. The conductive particles may be metal powders such as Ag and Cu. The particle size of the conductive particles may be, for example, 0.5 μm to 5 μm.

[0069] The battery 1000 may be constructed by stacking three or more battery elements and electrically connecting them in parallel. Each battery element does not have to be a single cell, and may be a battery pack of two or more.

[0070] The first current collector 110, the first active material layer 120, the solid electrolyte layer 300, the second active material layer 220, and the second current collector 210 may all have a rectangular general shape in plan view.

[0071] In Figure 1, the first current collector 110, the first active material layer 120, the solid electrolyte layer 300, the second active material layer 220, and the second current collector 210 are all the same size and their contours coincide in a plan view, but are not limited to this.

[0072] The first active material layer 120 may be smaller than the second active material layer 220.

[0073] The first active material layer 120 and the second active material layer 220 may be smaller than the solid electrolyte layer 300.

[0074] For example, if the solid electrolyte layer 300 covers at least one of the first active material layer 120 and the second active material layer 220, a portion of the solid electrolyte layer 300 may be in contact with at least one of the first current collector 110 and the second current collector 210.

[0075] The current collector only needs to be made of a conductive material.

[0076] The current collector may be a foil-like, plate-like, or mesh-like body made of, for example, stainless steel, nickel (Ni), aluminum (Al), iron (Fe), titanium (Ti), copper (Cu), palladium (Pd), gold (Au), or platinum (Pt), or an alloy of two or more of these materials.

[0077] The material of the current collector may be selected considering the manufacturing process, operating temperature, operating pressure, battery operating potential applied to the current collector, or conductivity. The current collector material may also be selected considering the tensile strength or heat resistance required by the battery. The current collector may be, for example, high-strength electrolytic copper foil or a clad material consisting of laminated dissimilar metal foils.

[0078] The current collector may have a thickness of, for example, 10 μm or more and 100 μm or less.

[0079] The surface of the current collector may be processed to have an uneven, rough surface in order to improve adhesion with the active material layer (i.e., the first active material layer 120 or the second active material layer 220). This improves, for example, the bonding strength of the current collector interface, thereby improving the mechanical and thermal reliability and cycle characteristics of the battery. In addition, the contact area between the current collector and the junction 16 is increased, thus reducing electrical resistance.

[0080] The first active material layer 120 may be in contact with the first current collector 110. The first active material layer 120 may cover the entire main surface of the first current collector 110.

[0081] The positive electrode active material layer contains the positive electrode active material.

[0082] The positive electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from the crystal structure at a potential higher than that of the negative electrode, and oxidation or reduction occurs accordingly.

[0083] The positive electrode active material is, for example, a compound containing lithium and a transition metal element. The compound is, for example, an oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element.

[0084] Examples of oxides containing lithium and a transition metal element are LiNi x M 1-x O2 (where M is at least one selected from the group consisting of Co, Al, Mn, V, Cr, Mg, Ca, Ti, Zr, Nb, Mo, and W, and 0 < x ≦ 1 is satisfied), such as lithium nickel composite oxides, layered oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganate (LiMn2O4), or lithium manganate having a spinel structure (for example, LiMn2O4, Li2MnO3, or LiMO2).

[0085] An example of a phosphate compound containing lithium and a transition metal element is lithium iron phosphate (LiFePO4) having an olivine structure.

[0086] As the positive electrode active material, sulfides such as sulfur (S) and lithium sulfide (Li2S) may be used. In this case, lithium niobate (LiNbO3) or the like may be coated on or added to the positive electrode active material particles.

[0087] Only one of these materials may be used as the positive electrode active material, or two or more of these materials may be combined and used.

[0088] To enhance lithium-ion conductivity or electronic conductivity, the positive electrode active material layer may contain materials other than the positive electrode active material. That is, the positive electrode active material layer may be a composite layer. Examples of such materials include solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive additives such as acetylene black, or binding binders such as polyethylene oxide and polyvinylidene fluoride.

[0089] The first active material layer 120 may have a thickness of 5 μm or more and 300 μm or less.

[0090] The second active material layer 220 may be in contact with the second current collector 210. The second active material layer 220 may cover the entire main surface of the second current collector 210.

[0091] The negative electrode active material layer contains the negative electrode active material.

[0092] The negative electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from its crystal structure at a lower potential than that of the positive electrode, and oxidation or reduction occurs as a result.

[0093] Examples of negative electrode active materials include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-fired carbon, or alloying materials combined with a solid electrolyte. Examples of alloying materials include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, Li 4.4 Pb, Li 4.4 Sn, Li 0.17 C, and lithium alloys such as LiC6, lithium titanate (Li4Ti5O 12 ) Oxides of lithium and transition metal elements, such as zinc oxide (ZnO), or silicon oxide (SiO2). x It is a metal oxide such as ).

[0094] The negative electrode active material may be one of these materials alone, or two or more of these materials may be used in combination.

[0095] In order to enhance the lithium ion conductivity or electron conductivity, the negative electrode active material layer may contain, in addition to the negative electrode active material, materials other than the negative electrode active material. Examples of such materials include solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive aids such as acetylene black, or binders for binding such as polyethylene oxide and polyvinylidene fluoride.

[0096] The second active material layer 220 may have a thickness of 5 μm or more and 300 μm or less.

[0097] The solid electrolyte layer 300 contains a solid electrolyte. The solid electrolyte layer 300 contains, for example, a solid electrolyte as a main component. The solid electrolyte layer 300 may consist only of a solid electrolyte.

[0098] The solid electrolyte may be a known solid electrolyte for a battery having ion conductivity. As the solid electrolyte, for example, a solid electrolyte that conducts metal ions such as lithium ions or magnesium ions can be used.

[0099] As the solid electrolyte, for example, an inorganic solid electrolyte such as a sulfide solid electrolyte or an oxide solid electrolyte can be used.

[0100] The sulfide solid electrolyte is, for example, a Li2S-P2S^5 system, a Li2S-SiS^2 system, a Li^2S-B^2S^3 system, a Li^2S-GeS^2 system, a Li^2S-SiS^2-LiI system, a Li^2S-SiS^2-Li^3PO^4 system, a Li^2S-Ge^2S^2 system, a Li^2S-GeS^2-P^2S^n system, or a Li^2S-GeS^2-ZnS system.

[0101] The oxide solid electrolyte is, for example, a lithium-containing metal oxide, a lithium-containing metal nitride, lithium phosphate (Li^3PO^4), or a lithium-containing transition metal oxide. Examples of the lithium-containing metal oxide are Li^2O-SiO^2 or Li^2O-SiO^2-P^2O^5. Examples of the lithium-containing metal nitride are Li x P y O 1-z Nz An example of a lithium-containing transition metal oxide is lithium titanium oxide.

[0102] As the solid electrolyte, only one of these materials may be used, or two or more of these materials may be used in combination.

[0103] The solid electrolyte layer 300 may contain a solid electrolyte having lithium ion conductivity.

[0104] The solid electrolyte layer 300 may also contain, in addition to the solid electrolyte, a binding binder such as polyethylene oxide or polyvinylidene fluoride.

[0105] The solid electrolyte layer 300 may have a thickness of 5 μm or more and 150 μm or less.

[0106] The material of the solid electrolyte may consist of aggregates of particles. Alternatively, the material of the solid electrolyte may consist of a sintered structure.

[0107] (Second Embodiment) The following describes a battery according to the second embodiment. Matters described in the first embodiment may be omitted as appropriate.

[0108] Figure 3 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1100 according to the second embodiment.

[0109] Figure 3(a) is a cross-sectional view of the battery 1100 according to the second embodiment. Figure 3(b) is a plan view of the battery 1100 according to the second embodiment, viewed from the positive side in the z-axis direction. Figure 3(a) shows a cross-section at the position indicated by line III-III in Figure 2(b).

[0110] As shown in Figure 3, unlike the first lead terminal 600 in the battery 1000 according to the first embodiment, the embossed shape of the first lead terminal 610 is partially arranged in the non-contact portion of the battery 1100. Except for this point, the first lead terminal 610 is the same as the first lead terminal 600 described in the first embodiment. Note that in Figure 3(b), the embossed shape provided on the first lead terminal 610 is represented by hatching applied to the first lead terminal 610.

[0111] With the above configuration, the stress on the first lead terminal 610, which is sandwiched between rigid battery elements and subjected to thermal cycling and confinement pressure, can be reduced. As a result, damage to the first lead terminal 610 can be suppressed. Furthermore, the embossed shape provided on the leading portion of the first lead terminal 610 from the side of the battery 1100 suppresses damage that occurs in areas prone to friction due to contact between the first lead terminal 610 and the side of the battery 1100. These features enhance the mechanical reliability of the first lead terminal 610.

[0112] The embossed shape may also be provided on the contact portion of the first lead terminal 610 that contacts at least one selected from the group consisting of the first battery element 400 and the second battery element 500. That is, the contact portion of the first lead terminal 610 may have the second embossed shape on at least a part of its surface. The description of the configuration of the second embossed shape provided on the contact portion is the same as the description of the configuration of the first embossed shape given in detail in the first embodiment, so a detailed description is omitted here.

[0113] In the battery 1100 according to the second embodiment, the embossed shape may be arranged on both the non-contact portion and the contact portion of the first lead terminal 610. The embossed shape of the first lead terminal 610 may be formed continuously on both the contact portion and the non-contact portion. In the battery 1100 shown in Figure 3, a portion of the surface of the non-contact portion does not have an embossed shape.

[0114] The width of the embossed shape in the non-contact portion of the first lead terminal 610 (i.e., the distance from the outer edge of the battery element to the area without the embossed shape in the non-contact portion) may be, for example, greater than or equal to the thickness of the first lead terminal 610 and less than or equal to the thickness of the battery element. This prevents the first lead terminal 610 from bending at the hard side corners of the battery 1100. As a result, damage near the lead-out portion of the first lead terminal 610 becomes less likely.

[0115] The embossed shape described above may also be provided on the second lead terminal 710 and the third lead terminal 810. In Figure 3(b), the embossed shape provided on the second lead terminal 710 is represented by hatching applied to the second lead terminal 710.

[0116] (Third embodiment) The following describes a battery according to a third embodiment. Matters described in the above embodiments may be omitted as appropriate.

[0117] Figure 4 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1200 according to the third embodiment.

[0118] Figure 4(a) is a cross-sectional view of the battery 1200 according to the third embodiment. Figure 4(b) is a plan view of the battery 1200 according to the third embodiment, viewed from the positive side in the z-axis direction. Figure 4(a) shows a cross-section at the position indicated by line IV-IV in Figure 4(b). Figure 5 is a plan view showing the schematic configuration of the outer edge and embossed pattern of the battery 1200 according to the third embodiment.

[0119] As shown in Figures 4 and 5, in the battery 1200, an embossed pattern is provided as a first embossed shape on the non-contact portion of the first lead terminal 620. As shown in Figure 5, in a plan view, the arrangement direction of the embossed unit shape 1 is not parallel to the direction in which the outer edges of the first battery element 400 and the second battery element 500 extend. That is, the arrangement direction has an inclination angle with respect to the direction in which the outer edges of the first battery element 400 and the second battery element 500 extend, and may have an inclination angle of approximately 45 degrees. As a result, the pattern is arranged symmetrically on both sides with respect to the perpendicular to the side surface of the battery 1200.

[0120] With the above configuration, the first lead terminal 620 has the property of being able to expand and contract due to its embossed shape, i.e., it is able to withstand tensile stress equally on both sides (for example, equally in the ±45 degree direction) with respect to the perpendicular to the side of the battery 1200. Therefore, the first lead terminal 620 can absorb stress over a wide range of stress directions, including the direction perpendicular to the side of the battery 1200 and the direction along the outer edge. Consequently, even with such an embossed pattern, damage to the first lead terminal 620 is reduced.

[0121] The embossed pattern described above may also be provided on the second lead terminal 720 and the third lead terminal 820.

[0122] (Fourth Embodiment) The following describes a battery according to the fourth embodiment. Matters described in the above embodiments may be omitted as appropriate.

[0123] Figure 6 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1300 according to the fourth embodiment.

[0124] Figure 6(a) is a cross-sectional view of the battery 1300 according to the fourth embodiment. Figure 6(b) is a plan view of the battery 1300 according to the fourth embodiment, viewed from the positive side in the z-axis direction. Figure 6(a) shows a cross-section at the position indicated by the line VI-VI in Figure 6(b).

[0125] As shown in Figure 6, in the battery 1300, the first embossed shape includes a plurality of linear embossed shapes. These plurality of linear embossed shapes 631 may be arranged parallel to each other as shown in Figure 6, and in this case, the linear embossed shapes 631 may be arranged to extend parallel to the long side of the first lead terminal 630.

[0126] With the above configuration, the progression of damage from the outer edge of the easily damaged first lead terminal 630 can be suppressed by dividing and absorbing it with the linear embossed shape.

[0127] The linear embossed shape 631 is preferably provided near the two long sides of the first lead terminal 630 that are prone to damage. For example, if two parallel linear embossed shapes 631 are provided, the stress will be distributed similarly between the two parallel linear embossed shapes.

[0128] The multiple linear embossed shapes 631 may be arranged parallel to each other, as shown in Figure 6, but they do not have to be parallel to each other. When the multiple linear embossed shapes 631 are not parallel to each other, it is advantageous for the distribution of stress between the embossments (reduction of concentration).

[0129] As a result of the above effects, it is possible to suppress the first lead terminal 630 from breaking across it. This reduces the occurrence of circuit breaks caused by damage to the first lead terminal 630. Therefore, a highly reliable and high-capacity battery can be realized.

[0130] Figure 6(b) shows an example in which one linear embossed shape 631 is provided along each of the long sides of the first lead terminal 630, for a total of two linear embossed shapes 631. However, the configuration is not limited to this, and additional linear embossed shapes or other embossed patterns may be provided. For example, one or more additional linear embossed shapes may be placed in the center of two parallel linear embossed shapes.

[0131] Multiple linear embossed shapes may be the same in shape and size as others, or they may be different in size.

[0132] Multiple linear embossed shapes, such as those provided on the first lead terminal 630, may also be provided on the second lead terminal 730 and the third lead terminal 830. As shown in Figure 6(b), the second lead terminal 730 may be provided with, for example, a linear embossed shape 731 that extends parallel to the long side of the second lead terminal 730.

[0133] (Fifth embodiment) The following describes a battery according to the fifth embodiment. Matters described in the above embodiments may be omitted as appropriate.

[0134] Figure 7 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1400 according to the fifth embodiment.

[0135] Figure 7(a) is a cross-sectional view of the battery 1400 according to the fifth embodiment. Figure 7(b) is a plan view of the battery 1400 according to the fifth embodiment, viewed from the positive side in the z-axis direction. Figure 7(a) shows a cross-section at the position indicated by the line VII-VII in Figure 7(b).

[0136] As shown in Figure 7, the battery 1400 has an embossed shape 641 only on the outer edge of the first lead terminal 640, along the outer edge. In other words, the center of the first lead terminal 640 does not have an embossed shape.

[0137] The outer edges of the lead terminals, which are prone to burrs and scratches during processing, are likely to become the starting point for breakage. Therefore, by providing an embossed shape 641 along the outer edge of the first lead terminal 640, the progression leading to breakage can be reduced. This suppresses the fracture of the first lead terminal 640.

[0138] For example, the width of the embossed shape 641 from the outer edge of the first lead terminal 640 may be approximately the amount of normal burr deformation, i.e., more than half the thickness of the first lead terminal 640, when addressing burrs from press punching. On the other hand, in the case of etching, processing burrs are hardly generated, but scratches (usually scratches of a few microns) may occur during the handling process of the manufacturing process. For this reason, the stress resistance of the first lead terminal 640 is improved by providing the embossed shape 641. When addressing defects caused by etching, the width of the embossed shape 641 from the outer edge may be smaller than the width of the embossed shape 641 for punching countermeasures as described above, and may be less than half the thickness of the first lead terminal 640. Thus, the width of the embossed shape from the outer edge may be set according to the degree of burrs and scratches on the outer edge of the lead terminal, and the width of the embossed shape 641 from the outer edge is not particularly limited. Also, if scratches or burrs occur only in specific locations, the embossed shape may be provided only around the outer edge of those specific locations. Alternatively, the width of the embossed shape may be increased only around the outer edge of that specific area.

[0139] With the above configuration, damage to the lead terminals caused by defects on the outer edge of the lead terminals (e.g., scratches or burrs) can be suppressed. Therefore, a highly reliable battery 1400 with high energy density and large capacity can be obtained.

[0140] The embossed shape provided on the first lead terminal 630 may also be provided on the second lead terminal 740 and the third lead terminal 840. As shown in Figure 7(b), the second lead terminal 740 may have an embossed shape 741 along its outer edge, for example, only on the outer edge of the second lead terminal 740.

[0141] (Sixth Embodiment) The following describes a battery according to the sixth embodiment. Matters described in the above embodiments may be omitted as appropriate.

[0142] Figure 8 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1500 according to the sixth embodiment.

[0143] Figure 8(a) is a cross-sectional view of the battery 1500 according to the sixth embodiment. Figure 8(b) is a plan view of the battery 1500 according to the sixth embodiment, viewed from the positive side in the z-axis direction. Figure 8(a) shows a cross-section at the position indicated by the line VIII-VIII in Figure 8(b).

[0144] As shown in Figure 8(b), in a plan view of the battery 1500, the second lead terminal 750 is positioned so as not to overlap with the third lead terminal 850. The other configurations of the battery 1500 are the same as those of the battery 1000 according to the first embodiment. Note that in Figure 8(b), the embossed shape on the lead terminals is represented by hatching applied to the lead terminals.

[0145] With the above configuration, the lead terminals on the side of the battery element are distributed rather than concentrated in a plan view. Therefore, stress caused by shocks and vibrations applied to the battery 1500 can be distributed over a wide area on the side of the battery element. As a result, cracks that occur at the lead terminals on the side of the battery element are suppressed. These cracks are those that occur when the lead terminals are pulled, causing the battery element to break. Furthermore, the effect of suppressing structural defects such as delamination at the lead terminals is obtained.

[0146] Although not shown in the diagram, in a plan view of the battery 1500, the second lead terminal 750 may be positioned so as to overlap only a portion of the third lead terminal 850.

[0147] Even with the above configuration, the lead terminals on the side of the battery element are distributed rather than concentrated in a plan view. Therefore, stress such as impact exerted from the lead terminals to the lead terminals on the battery element is distributed over a wide area on the side of the battery element. As a result, damage to the lead terminals on the battery element or delamination can be suppressed.

[0148] As described above, even with a thin and large-area stacked battery, reliability can be improved according to the battery of the sixth embodiment.

[0149] [Battery manufacturing method] The manufacturing method of the battery according to this disclosure will be described below. Here, as an example, the manufacturing method of battery 1000 according to the first embodiment will be described.

[0150] A method for manufacturing the first battery element 400 and the second battery element 500 will be described.

[0151] First, pastes are prepared for printing and forming the positive electrode active material layer and the negative electrode active material layer. As the solid electrolyte raw material used in the mixture of the positive electrode active material layer and the negative electrode active material layer, for example, a glass powder of Li2S-P2S5 system sulfide with an average particle size of approximately 10 μm and mainly composed of triclinic crystals is prepared. This glass powder is, for example, 2 × 10 -3 S / cm to 5×10 -3 It has an ionic conductivity of S / cm. As the positive electrode active material, for example, a layered Li·Ni·Co·Al composite oxide (e.g., LiNi) has an average particle size of about 5 μm. 0.8 Co 0.15 Al 0.05 O2 powder is used. A paste for the positive electrode active material layer is prepared by dispersing a mixture containing the above-mentioned positive electrode active material and the above-mentioned glass powder in an organic solvent or the like. As the negative electrode active material, for example, natural graphite powder with an average particle size of about 10 μm is used. A paste for the negative electrode active material layer is prepared by dispersing a mixture containing the above-mentioned negative electrode active material and the above-mentioned glass powder in an organic solvent or the like.

[0152] Next, copper foils, for example, with a thickness of approximately 15 μm, are prepared as the positive electrode current collector and the negative electrode current collector. By screen printing, pastes for the positive electrode active material layer and the negative electrode active material layer are printed on one surface of each copper foil in a predetermined shape and with a thickness of approximately 50 μm to 100 μm. The pastes for the positive electrode active material layer and the negative electrode active material layer are dried in a temperature range of 80°C to 130°C. In this way, the positive electrode active material layer is formed on the positive electrode current collector and the negative electrode active material layer is formed on the negative electrode current collector. This gives rise to the positive electrode layer and the negative electrode layer. The positive electrode layer and the negative electrode layer have a thickness of 30 μm or more and 60 μm or less.

[0153] Next, the aforementioned glass powder is dispersed in an organic solvent or the like to produce a paste for the solid electrolyte layer. The paste for the solid electrolyte layer is then printed onto the positive electrode layer and the negative electrode layer using a metal mask to a thickness of, for example, about 100 μm. After that, the positive and negative electrodes printed with the paste for the solid electrolyte layer are dried at a temperature in the range of 80°C to 130°C.

[0154] Next, a solid electrolyte printed on the positive electrode active material layer and a solid electrolyte printed on the negative electrode active material layer are stacked so that they are in contact with and facing each other.

[0155] Next, between the pressurized mold plate, specifically between the laminate and the pressurized mold plate, that is, on the upper surface of the current collector of the laminate, the elastic modulus is 5 × 10 6 An elastic sheet with a pressure of approximately Pa is inserted. The thickness of the elastic sheet is, for example, 70 μm. Then, the laminate is pressurized for 90 seconds while the pressurizing mold plate is heated to 50°C at a pressure of, for example, 300 MPa.

[0156] Through the above process, the first battery element 400 and the second battery element 500 are manufactured.

[0157] Next, when stacking the first battery element 400 and the second battery element 500, a thermosetting conductive paste containing silver particles is screen printed to a thickness of approximately 20 μm to 30 μm onto the surface of the current collector to which the first battery element 400 is joined. The second battery element 500 is then positioned in a predetermined location and pressed down, sandwiching a conductive foil (e.g., Cu foil) with lead terminals. The conductive foil is, for example, made of Cu and has a thickness of approximately 12 μm. In the battery 1000 according to the first embodiment, the first battery element 400 and the second battery element 500 are electrically connected in parallel. Therefore, in this case, elements of the same polarity are joined together. The lead terminals are pre-pressurized with a mold, so that at least a portion of the surface that will not come into contact with either the first battery element 400 or the second battery element 500 is embossed. By repeating this process, a multilayer battery can be made. After this, for example, approximately 1 kg / cm³ is applied. 2 The material is left to stand while pressure is applied, and then subjected to a heat-curing treatment at a temperature of approximately 100°C to approximately 300°C for 60 minutes, after which it is gradually cooled to room temperature. This makes it possible to manufacture a battery in which the first battery element 400 and the second battery element 500 are connected in parallel, i.e., a battery 1000.

[0158] Note that the method and sequence of battery formation are not limited to the examples described above.

[0159] For example, an insulating resin material may be applied to the side surface of the battery element by screen printing.

[0160] In the manufacturing method described above, an example was shown in which the paste for the positive electrode active material layer, the paste for the negative electrode active material layer, the paste for the solid electrolyte layer, and the conductive paste are applied by printing, but this is not the only example. Examples of printing methods include the doctor blade method, calendering method, spin coating method, dip coating method, inkjet method, offset method, die coating method, or spray method.

[0161] In the manufacturing method described above, a thermosetting conductive paste containing silver metal particles was given as an example of the conductive paste, but it is not limited to this. Furthermore, the resin used in the thermosetting conductive paste can be any resin that functions as a binding binder, and a suitable resin can be selected depending on the manufacturing process adopted, considering factors such as printability and coatability. Resins used in thermosetting conductive paste include, for example, thermosetting resins. Examples of thermosetting resins include (i) amino resins such as urea resin, melamine resin, and guanamine resin; (ii) epoxy resins such as bisphenol A type, bisphenol F type, phenol novolac type, and alicyclic type; (iii) oxetane resin; (iv) phenol resins such as resol type and novolac type; and (v) silicone-modified organic resins such as silicone epoxy and silicone polyester. Only one of these materials may be used as the resin, or two or more of these materials may be used in combination.

[0162] The batteries and their manufacturing methods described herein have been explained based on embodiments, but this disclosure is not limited to these embodiments. Without departing from the spirit of this disclosure, various modifications to the embodiments that a person skilled in the art could conceive, as well as other forms constructed by combining some components from different embodiments, are also included in the scope of this disclosure. [Industrial applicability]

[0163] The battery relating to this disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles. [Explanation of symbols]

[0164] 100 1st electrode 110 First current collector 120 First active material layer 200 2nd electrode 210 Second current collector 220 Second active material layer 300 solid electrolyte layer 400 First battery element 500 Second battery component 600, 610, 620, 630, 640 First lead terminal 700, 710, 720, 730, 740, 750 Second lead terminal 800, 810, 820, 830, 840, 850 Third lead terminal

Claims

1. First battery element, A second battery element is stacked on the first battery element and electrically connected in parallel with the first battery element, A first lead terminal is positioned between the first battery element and the second battery element and is electrically connected to the first battery element and the second battery element, Equipped with, The first lead terminal has a contact portion that contacts at least one selected from the group consisting of the first battery element and the second battery element, and a non-contact portion that does not contact either the first battery element or the second battery element. The non-contact portion is an exposed portion that protrudes outward from the side surface of the laminate of the first battery element and the second battery element. The non-contact portion has a first embossed shape on at least a part of its surface. The maximum height roughness Rz of the first embossed shape is 10 μm or more and 15 μm or less. The first embossed shape has a periodic structure in which embossed unit shapes are repeatedly arranged at predetermined intervals. If the first embossed shape includes a linear embossed shape, the direction in which the linear embossed shape extends intersects, in a plan view, with the direction in which the outer edges of the first and second battery elements, corresponding to the side surface of the laminate from which the non-contact portion protrudes, extend. battery.

2. The predetermined interval is greater than or equal to the thickness of the first lead terminal. The battery according to claim 1.

3. The first embossed shape includes a plurality of the linear embossed shapes, The battery according to claim 1 or 2.

4. The contact portion of the first lead terminal has a second embossed shape on at least a part of its surface. The battery according to claim 1 or 2.

5. The first embossed shape is located on the outer edge of the first lead terminal. The battery according to claim 1 or 2.

6. The second lead terminal is electrically connected to the first battery element, The third lead terminal is electrically connected to the second battery element, Furthermore, The second lead terminal, the first battery element, the first lead terminal, the second battery element, and the third lead terminal are arranged in this order in the stacking direction of the first battery element and the second battery element. The battery according to claim 1 or 2.

7. In a plan view, the second lead terminal overlaps with the third lead terminal by only a portion. The battery according to claim 6.

8. The second lead terminal does not overlap with the third lead terminal in a plan view. The battery according to claim 6.

9. The battery according to claim 6, wherein the second lead terminal has the same shape as the third lead terminal in a plan view.

10. The first battery element and the second battery element are solid-state batteries. The battery according to claim 1 or 2.

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