Battery and method for manufacturing a battery

Abstract

This battery (1000) is provided with a battery cell (2000). The battery cell (2000) comprises a positive electrode active material layer (120), a negative electrode active material layer (110), and a solid electrolyte layer (130) that is arranged between the positive electrode active material layer (120) and the negative electrode active material layer (110). A lateral surface of the battery cell (2000) is provided with a streak-like cut mark (800) that is inclined to the thickness direction of the battery cell (2000) when the lateral surface of the battery cell (2000) is viewed in plan.

Description

Technical Field

[0001] The present disclosure relates to a battery and a method for manufacturing the battery.

Background Art

[0002] In the manufacture of a battery, the ends of a battery cell or components of a battery cell may be cut for determining the shape of the battery and removing unnecessary parts.

[0003] Patent Document 1 discloses performing an insulation treatment on a temporary cut surface of a current collector.

[0004] Patent Document 2 discloses providing an external electrode of a current collector on the side surface of a unit laminate of a plurality of electrostrictive effect elements connected by an adhesive and then interconnecting them.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the prior art, further suppression of short circuits in a battery using a solid electrolyte and improvement of reliability such as quality stability are desired.

[0007] Unlike a liquid-based battery, a battery using a solid electrolyte has no separator, so it is important to suppress a decrease in reliability caused by a cut surface.

[0008] Therefore, the present disclosure provides a battery having high reliability and a method for manufacturing the battery.

Means for Solving the Problems

[0009] A battery in one aspect of the present disclosure comprises at least one battery cell, the at least one battery cell having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, wherein the side surface of the at least one battery cell is provided with striated recesses or protrusions that are inclined with respect to the thickness direction of the at least one battery cell when the side surface of the at least one battery cell is viewed from above.

[0010] Furthermore, a method for manufacturing a battery in one aspect of the present disclosure is a method for manufacturing a battery comprising a battery cell having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, the method including a cutting step of cutting the battery cell with a cutting blade, wherein in the cutting step, the battery cell is cut downward with the cutting blade while sliding at least one of the battery cell and the cutting blade in the longitudinal direction of the cutting blade. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a battery with high reliability and a method for manufacturing a battery. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic side view showing the general configuration of the battery in Embodiment 1. [Figure 2] Figure 2 is a schematic side view showing the general configuration of the battery in the comparative example. [Figure 3A] Figure 3A is a schematic front view showing an example of a cutting device used for cutting battery cells in Embodiment 1. [Figure 3B] Figure 3B is a schematic side view showing an example of a cutting device used for cutting battery cells in Embodiment 1. [Figure 3C] Figure 3C is a diagram illustrating an example of the movement of a cutting device. [Figure 4] Figure 4 is a diagram illustrating another example of the movement of the cutting device. [Figure 5]Figure 5 is a schematic side view showing the general configuration of a battery in a modified example of Embodiment 1. [Figure 6] Figure 6 is a schematic side view showing the general configuration of the battery in Embodiment 2. [Figure 7] Figure 7 is a schematic side view showing the general configuration of another battery in Embodiment 2. [Figure 8] Figure 8 is a schematic side view showing the general configuration of yet another battery in Embodiment 2. [Modes for carrying out the invention]

[0013] (Knowledge obtained to obtain one aspect of this disclosure) As mentioned above, in the manufacturing of batteries, the ends of battery cells are sometimes cut to determine the shape of the battery and to remove unnecessary parts. The cut surface formed by cutting a battery cell along its thickness direction becomes the side surface of the battery cell. In this case, for example, if a battery cell having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer between the positive electrode current collector and the negative electrode current collector is cut all at once, multiple roughly parallel striated cut marks will be generated on the cut surface, from the positive electrode current collector to the negative electrode current collector.

[0014] One of the typical causes of short circuits between the positive and negative electrodes in batteries containing solid electrolytes is dielectric breakdown due to edge discharge along the sides of the battery cell. The striated cut marks generated by a single cut are recesses or protrusions on the sides, and therefore electric fields tend to concentrate at these striated cut marks. These areas where electric fields concentrate tend to become the starting and ending points of edge discharge. For this reason, the portion of the striated cut mark located on the positive electrode current collector or positive electrode active material layer and the portion located on the negative electrode current collector or negative electrode active material layer become the starting and ending points of edge discharge, and edge discharge is likely to occur along these striated cut marks. Therefore, the shorter the length of the striated cut mark between the positive electrode current collector or positive electrode active material layer and the negative electrode current collector or negative electrode active material layer, the greater the risk of edge discharge.

[0015] The present disclosure has been made based on such findings, and provides a battery and a method for manufacturing a battery that can enhance reliability by suppressing edge surface discharge caused by linear concave or convex portions such as linear cutting marks provided on the side surface of a battery cell.

[0016] (Summary of the Present Disclosure) The summary of one aspect of the present disclosure is as follows.

[0017] A battery according to one aspect of the present disclosure includes at least one battery cell, and the at least one battery cell has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. On the side surface of the at least one battery cell, when the side surface of the at least one battery cell is viewed in plan view, a linear concave or convex portion inclined with respect to the thickness direction of the at least one battery cell is provided.

[0018] As described above, an electric field tends to concentrate on the linear concave or convex portion provided on the side surface of the battery cell, and the linear concave or convex portion tends to be the start and end points of edge surface discharge on the side surface. In this aspect, since the linear concave or convex portion is inclined with respect to the thickness direction of the battery cell when the side surface of the battery cell is viewed in plan view, the linear concave or convex portion between the negative electrode layer and the positive electrode layer becomes longer than when it is not inclined. That is, the distance between the portion provided on the negative electrode layer and the portion provided on the positive electrode layer of the linear concave or convex portion where the electric field tends to concentrate becomes longer. Therefore, by suppressing the occurrence of edge surface discharge on the side surface of the battery cell, the occurrence of a short circuit due to dielectric breakdown can be suppressed, and a highly reliable battery can be realized.

[0019] Further, for example, when the side surface of the at least one battery cell is viewed in plan view, the angle formed by the linear concave or convex portion and the thickness direction may be 18 degrees or more and 84 degrees or less.

[0020] As a result, when viewing the side of the battery cell from above, the grooves or protrusions between the negative and positive electrode layers become 5% or more longer compared to cases where they are not inclined with respect to the thickness direction of the battery cell, thereby further improving the reliability of the battery. Furthermore, for example, when grooves or protrusions are formed by cutting downwards while sliding the cutting blade or the battery cell in a direction perpendicular to the thickness direction of the battery cell, the sliding stroke of the cutting blade or the battery cell becomes 10 times or less compared to the minimum stroke of the cutting blade required to cut the battery cell. Therefore, the battery cell cutting equipment can be made more compact.

[0021] Furthermore, for example, when viewing the side surface of at least one battery cell from above, the angle between the striated recess or protrusion and the thickness direction may be between 25 degrees and 78 degrees.

[0022] As a result, when the side of the battery cell is viewed from above, the grooves or protrusions between the negative and positive electrode layers become 10% or more longer compared to when they are not inclined with respect to the thickness direction of the battery cell, further improving the reliability of the battery. Also, for example, when grooves or protrusions are formed by cutting downwards while sliding the cutting blade or the battery cell in a direction perpendicular to the thickness direction of the battery cell, the sliding stroke of the cutting blade or the battery cell becomes 5 times or less than the minimum stroke of the cutting blade or the battery cell required to cut the battery cell. Therefore, the battery cell cutting equipment can be made even more compact.

[0023] Furthermore, for example, when the side surface of at least one battery cell is viewed from above, the striated recesses or protrusions may be curved.

[0024] This allows for longer groove-like recesses or protrusions between the negative and positive electrode layers, thereby improving the reliability of the battery.

[0025] Furthermore, for example, the depth of the recess or the height of the protrusion in the groove-like recess or protrusion may be 0.1 μm or more.

[0026] Even when such striated recesses or protrusions are larger than a predetermined size, and electric fields tend to concentrate in these areas, the reliability of the battery can be improved if the striated recesses or protrusions are inclined with respect to the thickness direction of the battery cell when the side of the battery cell is viewed from above.

[0027] Furthermore, for example, the at least one battery cell may be a plurality of battery cells, and the plurality of battery cells may be stacked.

[0028] This improves the reliability of batteries, even in stacked batteries where battery cells are stacked on top of each other.

[0029] Furthermore, for example, the groove-like recesses or protrusions in adjacent battery cells among the plurality of battery cells may be continuous.

[0030] Since these striated recesses or protrusions can be formed by cutting multiple battery cells together while they are stacked, the battery manufacturing process can be simplified.

[0031] Furthermore, for example, the groove-like recesses or protrusions in each adjacent battery cell among the plurality of battery cells may be inclined in opposite directions with respect to the thickness direction when the side surfaces of each adjacent battery cell are viewed from above.

[0032] This design makes it less likely for damage to the battery to propagate from the grooved recesses or protrusions, even if the battery is subjected to impact or other shocks, thereby improving the battery's reliability.

[0033] Furthermore, a method for manufacturing a battery in one aspect of the present disclosure is a method for manufacturing a battery comprising a battery cell having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, the method including a cutting step of cutting the battery cell with a cutting blade, wherein in the cutting step, the battery cell is cut downward with the cutting blade while sliding at least one of the battery cell and the cutting blade in the longitudinal direction of the cutting blade.

[0034] Thus, during the cutting process, at least one of the battery cell or the cutting blade slides in the longitudinal direction of the cutting blade, causing the trajectory of the cutting blade on the cut surface to be inclined relative to the thickness direction of the battery cell. As a result, even if striated recesses or protrusions are formed on the cut surface by the cutting blade, the cut marks are inclined relative to the thickness direction of the battery cell when the cut surface of the battery cell is viewed from above. Therefore, when the side view of the battery cell is viewed from above, the cut marks between the negative electrode layer and the positive electrode layer become longer compared to the case where the cut marks are not inclined relative to the thickness direction of the battery cell. Thus, by suppressing the occurrence of edge discharge at the cut surface of the battery cell, the occurrence of short circuits due to dielectric breakdown is suppressed, and highly reliable batteries can be manufactured. Furthermore, since the battery cell is cut not only by pressing down with the cutting blade but also by sliding the tip of the cutting blade, the cutting resistance can be reduced. This reduces the stress applied to the battery cell during cutting, thus reducing the risk of damage such as microcracks occurring inside the battery cell near the cut surface due to stress, and thus highly reliable batteries can be manufactured.

[0035] Embodiments of the present disclosure will be described below with reference to the drawings.

[0036] The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, processes, and order of processes shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0037] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0038] Furthermore, in this specification, terms indicating relationships between elements such as parallelism, terms indicating the shape of elements such as rectangles, and numerical ranges do not represent only strict meanings, but also include substantially equivalent ranges, such as differences of a few percent.

[0039] (Embodiment 1) [composition] First, the configuration of the battery in Embodiment 1 will be described. Figure 1 is a schematic side view showing the general configuration of the battery 1000 in Embodiment 1. Figure 1 is a plan view of the side surface connecting the two main surfaces of the battery 1000. Figure 1 is also a plan view of the side surface of the battery cell 2000 provided in the battery 1000. Viewing the side surface from a plan view can also be described as viewing the battery 1000 or the battery cell 2000 along the direction normal to the side surface of the battery 1000 or the battery cell 2000.

[0040] As shown in Figure 1, the battery 1000 in Embodiment 1 comprises at least one battery cell 2000. The battery cell 2000 is, for example, rectangular, but may have other shapes. In the battery 1000, there is one battery cell 2000, but the battery 1000 may comprise multiple battery cells. Batteries comprising multiple battery cells will be described later. The battery cell 2000 comprises a negative electrode current collector 210, a negative electrode active material layer 110, a solid electrolyte layer 130, a positive electrode active material layer 120, and a positive electrode current collector 220. In this disclosure, the negative electrode active material layer 110 is an example of a negative electrode layer, and the positive electrode active material layer 120 is an example of a positive electrode layer.

[0041] The negative electrode current collector 210, the negative electrode active material layer 110, the solid electrolyte layer 130, the positive electrode active material layer 120, and the positive electrode current collector 220 are stacked in this order. Note that the battery cell 2000 only needs to include at least the negative electrode active material layer 110, the solid electrolyte layer 130, and the positive electrode active material layer 120. For example, the battery cell 2000 does not need to include at least one of the negative electrode current collector 210 and the positive electrode current collector 220.

[0042] The negative electrode active material layer 110 and the positive electrode active material layer 120 face each other via a solid electrolyte layer 130. The negative electrode active material layer 110 is located between the negative electrode current collector 210 and the solid electrolyte layer 130. The positive electrode active material layer 120 is located between the positive electrode current collector 220 and the solid electrolyte layer 130.

[0043] The negative electrode active material layer 110 is a layer containing a negative electrode material. The negative electrode material used in the negative electrode active material layer 110 includes, for example, a negative electrode active material. The negative electrode active material layer 110 is positioned opposite the positive electrode active material layer 120.

[0044] Various materials capable of releasing and inserting ions such as lithium (Li) or magnesium (Mg) can be used as the negative electrode active material contained in the negative electrode active material layer 110. Examples of negative electrode active materials that can be used include graphite and metallic lithium.

[0045] Furthermore, the negative electrode material used in the negative electrode active material layer 110 may further contain a solid electrolyte, such as an inorganic solid electrolyte. As an inorganic solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte may be used. As a sulfide solid electrolyte, for example, a mixture of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) may be used. Furthermore, the negative electrode material used in the negative electrode active material layer 110 may further contain a conductive material, such as acetylene black. Furthermore, the negative electrode material used in the negative electrode active material layer 110 may further contain a binding binder, such as polyvinylidene fluoride.

[0046] The negative electrode active material layer 110 can be manufactured by coating the surface of the negative electrode current collector 210 with a paste-like coating made by kneading the negative electrode material used in the negative electrode active material layer 110 together with a solvent, and then drying the coating. To increase the density of the negative electrode active material layer 110, the negative electrode plate containing the negative electrode active material layer 110 and the negative electrode current collector 210 may be pressed after drying. The thickness of the negative electrode active material layer 110 is, for example, 5 μm to 300 μm, but is not limited to this.

[0047] The positive electrode active material layer 120 is a layer containing a positive electrode material. The positive electrode material is the material that constitutes the counter electrode to the negative electrode material. The positive electrode material used in the positive electrode active material layer 120 includes, for example, a positive electrode active material.

[0048] Various materials capable of releasing and inserting ions such as Li or Mg can be used as the positive electrode active material contained in the positive electrode active material layer 120. Examples of positive electrode active materials that can be used include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel oxide composite oxide (LMNO), lithium-manganese-cobalt oxide composite oxide (LMCO), lithium-nickel-cobalt oxide composite oxide (LNCO), and lithium-nickel-manganese-cobalt oxide composite oxide (LNMCO).

[0049] Furthermore, the positive electrode material used in the positive electrode active material layer 120 may further contain a solid electrolyte, such as an inorganic solid electrolyte. The solid electrolyte may be one of the materials exemplified above as the solid electrolyte included in the negative electrode material. The surface of the positive electrode active material may also be coated with a solid electrolyte. Additionally, the positive electrode material used in the positive electrode active material layer 120 may further contain a conductive material, such as acetylene black. Furthermore, the positive electrode material used in the positive electrode active material layer 120 may further contain a binding binder, such as polyvinylidene fluoride.

[0050] The positive electrode active material layer 120 can be manufactured by coating the surface of the positive electrode current collector 220 with a paste-like coating made by kneading the positive electrode material to be used in the positive electrode active material layer 120 together with a solvent, and then drying the coating. In order to increase the density of the positive electrode active material layer 120, the positive electrode plate including the positive electrode active material layer 120 and the positive electrode current collector 220 may be pressed after drying. The thickness of the positive electrode active material layer 120 is, for example, 5 μm to 300 μm, but is not limited to this.

[0051] The solid electrolyte layer 130 is placed between the negative electrode active material layer 110 and the positive electrode active material layer 120. The solid electrolyte layer 130 is in contact with both the negative electrode active material layer 110 and the positive electrode active material layer 120. The solid electrolyte layer 130 is a layer containing an electrolyte material. As the electrolyte material, generally known electrolytes for batteries can be used. The thickness of the solid electrolyte layer 130 may be 5 μm or more and 300 μm or less, or 5 μm or more and 100 μm or less.

[0052] The solid electrolyte layer 130 contains a solid electrolyte as the electrolyte material. The battery 1000 may be, for example, an all-solid-state battery.

[0053] As the solid electrolyte, the materials exemplified as solid electrolytes included in the negative electrode material described above may be used. In addition, the solid electrolyte layer 130 may contain a binding binder such as polyvinylidene fluoride in addition to the electrolyte material.

[0054] In the battery cell 2000, the negative electrode active material layer 110, the positive electrode active material layer 120, and the solid electrolyte layer 130 are maintained in a parallel plate shape. This suppresses the occurrence of cracking or collapse due to bending. Alternatively, the negative electrode active material layer 110, the positive electrode active material layer 120, and the solid electrolyte layer 130 may be smoothly curved together.

[0055] The negative electrode current collector 210 and the positive electrode current collector 220 are both conductive materials. The negative electrode current collector 210 and the positive electrode current collector 220 may each be, for example, a conductive thin film. As materials for constituting the negative electrode current collector 210 and the positive electrode current collector 220, metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni) can be used.

[0056] The negative electrode current collector 210 is positioned in contact with the negative electrode active material layer 110. For example, a metal foil such as SUS foil, Cu foil, or Ni foil may be used as the negative electrode current collector 210. The thickness of the negative electrode current collector 210 is, for example, 5 μm to 100 μm, but is not limited to this. The negative electrode current collector 210 may also include a current collector layer, for example, a layer containing a conductive material, in the portion in contact with the negative electrode active material layer 110.

[0057] The positive electrode current collector 220 is positioned in contact with the positive electrode active material layer 120. For example, a metal foil such as SUS foil, Al foil, Cu foil, or Ni foil may be used as the positive electrode current collector 220. The thickness of the negative electrode current collector 210 is, for example, 5 μm to 100 μm, but is not limited to this. The positive electrode current collector 220 may also include a current collector layer, for example, a layer containing a conductive material, in the portion in contact with the positive electrode active material layer 120.

[0058] The side surface of the battery cell 2000 is a cut surface formed by cutting the negative electrode current collector 210, the negative electrode active material layer 110, the solid electrolyte layer 130, the positive electrode current collector 220, and the positive electrode active material layer 120 all at once with a cutting blade. The side surface of the battery cell 2000 is formed by cutting the battery cell 2000 all at once so that a cut surface along the thickness direction of the battery cell 2000 is formed. On the side surface of the battery cell 2000, for example, the negative electrode current collector 210, the negative electrode active material layer 110, the solid electrolyte layer 130, the positive electrode current collector 220, and the positive electrode active material layer 120 are exposed. Note that not all layers and current collectors constituting the battery cell 2000 are exposed on the side surface of the battery cell 2000.

[0059] The side surface of the battery cell 2000 is provided with striated cut marks 800, which are examples of striated recesses or protrusions. The striated cut marks 800 are the result of the aforementioned single-piece cutting. The striated cut marks 800 are minute striated recesses or protrusions on the side surface that occur due to the cutting properties, stress distribution, and non-uniformity of minute collapse of the materials in each layer when the cutting blade comes into contact with the battery cell 2000. The striated cut marks 800 are, for example, linear. The striated cut marks 800 are provided on the side surface of the battery cell 2000 so as to connect the negative electrode active material layer 110 and the positive electrode active material layer 120. The striated cut marks 800 may also be provided on the side surface of the battery cell 2000 so as to connect the negative electrode current collector 210 and the positive electrode current collector 220. The groove-like cut marks 800 provided on the side surface of the battery cell 2000 are inclined with respect to the thickness direction of the battery cell 2000 when the side surface is viewed from above, and there is a significant angle difference θ between the thickness direction of the battery cell 2000 and the groove-like cut marks 800 that is not zero. The thickness direction of the battery cell 2000 when the side surface is viewed from above is the direction indicated by arrow Z, or in other words, the short-side direction of each layer when the side surface of the battery cell 2000 is viewed from above. Furthermore, the thickness direction of the battery cell 2000 when the side surface is viewed from above is also the direction in which the negative electrode active material layer 110, the solid electrolyte layer 130, and the positive electrode active material layer 120 are aligned when the side surface is viewed from above. The angle difference θ is the angle between the groove-like cut marks 800 and the thickness direction of the battery cell 2000 when the side surface is viewed from above.

[0060] Multiple groove-like cuts 800 are provided on the side surface of the battery cell 2000, and these groove-like cuts 800 are parallel to each other. That is, the distance between adjacent groove-like cuts 800 is the same at any position. Furthermore, the groove-like cuts 800 may consist of a mixture of recessed groove-like cuts 800 and convex groove-like cuts 800.

[0061] As will be explained in more detail later, the striated cut marks 800 are formed when the battery cell 2000 is cut with a cutting blade, such that the relative direction of movement of the cutting blade relative to the battery cell 2000 is inclined with respect to the thickness direction of the battery cell 2000.

[0062] Here, the effects of battery 1000 will be explained with reference to battery 1000X in the comparative example. Figure 2 is a schematic side view showing the general configuration of battery 1000X in the comparative example. Figure 2 is a plan view of the side of battery 1000X.

[0063] As shown in Figure 2, the side surface of the battery cell 2000 of the battery 1000X is provided with groove-like cut marks 800X that are not inclined with respect to the thickness direction of the battery cell 2000 when the side surface of the battery cell 2000 is viewed from above.

[0064] As described above, recesses or protrusions on the side surface tend to concentrate electric fields and are likely to become the starting and ending points of edge discharge on the side surface. When the side surface of the battery cell 2000 is viewed from above, the striated cut marks 800X are not inclined with respect to the thickness direction of the battery cell 2000, and are therefore provided to connect the negative electrode current collector 210 or negative electrode active material layer 110 and the positive electrode current collector 220 or positive electrode active material layer 120 by the shortest distance. For this reason, edge discharge is likely to occur along the striated cut marks 800X.

[0065] On the other hand, in the battery 1000 in this embodiment shown in Figure 1, the striated cut marks 800 are inclined with respect to the thickness direction of the battery cell 2000 when the side surface of the battery cell 2000 is viewed from above. Therefore, compared to the striated cut marks 800X in the comparative example, the striated cut marks 800 between the negative electrode current collector 210 or negative electrode active material layer 110 and the positive electrode current collector 220 or positive electrode active material layer 120 are longer. In other words, the distance between the portion of the striated cut marks 800 that is located on the negative electrode current collector 210 or negative electrode active material layer 110 and the portion located on the positive electrode current collector 220 or positive electrode active material layer 120, where electric fields tend to concentrate, is increased. Thus, by suppressing the occurrence of edge discharge on the side surface of the battery cell 2000, the occurrence of short circuits due to dielectric breakdown is suppressed, and a highly reliable battery 1000 can be realized.

[0066] The angle difference θ may be, for example, between 18 degrees and 84 degrees, or between 25 degrees and 78 degrees.

[0067] When the angle difference θ is 18 degrees or more, the distance between the portion of the grooved cut mark 800 located on the negative electrode current collector 210 or negative electrode active material layer 110 and the portion located on the positive electrode current collector 220 or positive electrode active material layer 120 increases by 5% or more compared to the case where there is no angle difference θ. As a result, the risk of dielectric breakdown due to edge discharge along the side surface of the battery cell 2000 can be further reduced. Furthermore, when the angle difference θ is 25 degrees or more, the distance between the portion of the grooved cut mark 800 located on the negative electrode current collector 210 or negative electrode active material layer 110 and the portion located on the positive electrode current collector 220 or positive electrode active material layer 120 increases by 10% or more compared to the case where there is no angle difference θ. As a result, the risk of dielectric breakdown due to edge discharge along the side surface of the battery cell 2000 can be further reduced.

[0068] Furthermore, if the angle difference θ is 84 degrees or less, for example, when a groove-like cut mark 800 is formed by sliding the cutting blade or the battery cell 2000 downwards in a direction perpendicular to the thickness direction of the battery cell 2000, as in the manufacturing method described later, the sliding stroke of the battery cell 2000 or the cutting blade will be 10 times or less than the minimum stroke of the cutting blade required to cut the battery cell 2000 (i.e., the stroke in the downward cutting direction). Therefore, the cutting equipment for the battery cell 2000 can be made more compact. Also, if the angle difference θ is 78 degrees or less, the sliding stroke will be 5 times or less than the minimum stroke. Therefore, the cutting equipment for the battery cell 2000 can be made even more compact.

[0069] The depth of the recess or the height of the protrusion in the groove-shaped cut mark 800 is, for example, 0.1 μm or more. Even in cases where electric field concentration is likely to occur at the groove-shaped cut mark 800, edge discharge can be suppressed due to the effect of the groove-shaped cut mark 800 being inclined with respect to the thickness direction of the battery cell 2000, as in this embodiment. Furthermore, from the viewpoint of suppressing edge discharge and suppressing damage originating from the groove-shaped cut mark 800, the depth of the recess or the height of the protrusion in the groove-shaped cut mark 800 is, for example, 100 μm or less, and may be 10 μm or less. When multiple groove-shaped cut marks 800 are provided, for example, the depth of the deepest recess or the height of the highest protrusion in the multiple groove-shaped cut marks 800 is 0.1 μm or more and 100 μm or less, or 0.1 μm or more and 10 μm or less.

[0070] [Manufacturing method] Next, we will explain the manufacturing method of battery 1000.

[0071] A method for manufacturing the battery 1000 includes, for example, a stacking step and a cutting step.

[0072] In the lamination process, for example, a battery cell 2000 is formed comprising a negative electrode current collector 210, a negative electrode active material layer 110, a solid electrolyte layer 130, a positive electrode active material layer 120, and a positive electrode current collector 220. In the lamination process, for example, the battery cell 2000 is formed by sequentially laminating the negative electrode current collector 210, the negative electrode active material layer 110, the solid electrolyte layer 130, the positive electrode active material layer 120, and the positive electrode current collector 220 in this order. The battery cell 2000 is formed, for example, by coating and drying a paste-like coating, which is made by kneading the materials of the negative electrode active material layer 110, the positive electrode active material layer 120, and the solid electrolyte layer 130 together with a solvent, onto the current collector or the surface of each layer. Alternatively, a negative electrode plate may be prepared by laminating a negative electrode active material layer 110 and a solid electrolyte layer 130 in that order on a negative electrode current collector 210, and a positive electrode plate may be prepared by laminating a positive electrode active material layer 120 and a solid electrolyte layer 130 on a positive electrode current collector 220. The battery cell 2000 may then be formed by joining the negative electrode plate and the positive electrode plate via the solid electrolyte layer 130. In the lamination process, pressing may be performed to increase density and compressive bonding during the formation of each layer and during the joining of the negative electrode plate and the positive electrode plate. It should be noted that the method for forming the battery cell 2000 is not limited to the above example, and it can be formed by known battery manufacturing methods.

[0073] Next, in the cutting process, the battery cells 2000 formed in the lamination process are cut with a cutting blade. At this time, the aforementioned striated cut marks 800 are formed on the cut surface formed when the battery cells 2000 are cut by the cutting blade. The striated cut marks 800 are formed due to the cutting properties, stress distribution, and non-uniformity of minute collapse of the materials in each layer when the cutting blade and the battery cells 2000 come into contact. In this way, a battery 1000 is formed in which the cut surface on which the striated cut marks 800 are formed becomes the side surface of the battery cells 2000.

[0074] In addition, during the cutting process, instead of preparing the battery cells 2000 formed in the lamination process, it is also possible to obtain battery cells 2000 with each layer already laminated and use those pre-prepared battery cells 2000.

[0075] Here, a method for forming groove-like cut marks 800 that are inclined with respect to the thickness direction of the battery cell 2000 when the side surface of the battery cell 2000 is viewed from above will be described. Figure 3A is a schematic front view showing an example of a cutting device 600 used for cutting the battery cell 2000. Figure 3B is a schematic side view showing an example of a cutting device 600 used for cutting the battery cell 2000. Figure 3C is a diagram illustrating an example of the movement of the cutting device 600. Note that in Figures 3A and 3B, the cutting unit 601 is shown with a dot pattern, but this is for ease of viewing and does not mean that the actual cutting unit 601 has a dot pattern. Also, in Figure 3C, for ease of viewing, components of the cutting device 600 other than the movable upper blade 701 and the support unit 753 are omitted from the illustration.

[0076] One method for forming slit-like cut marks 800 that are inclined with respect to the thickness direction of the battery cell 2000 is to use a cutting device 600 schematically shown in Figures 3A and 3B.

[0077] The cutting device 600 comprises a cutting unit 601, a slide unit 602, and a support unit 753.

[0078] The cutting unit 601 is entirely mounted on the slide unit 602. The cutting unit 601 has a dot pattern as shown in Figures 3A and 3B. The cutting unit 601 includes a cutting blade 700 and a cutting blade actuator 751.

[0079] The cutting blade 700 consists of a movable upper blade 701 and a fixed lower blade 702. The lower end of the movable upper blade 701 is the cutting edge of the movable upper blade 701, and the upper end of the fixed lower blade 702 is the cutting edge of the fixed lower blade 702. The movable upper blade 701 is connected to the lower end of the cutting blade actuator 751 and can move up and down by the cutting blade actuator 751. Specifically, the end of the movable upper blade 701 opposite to the cutting edge is connected to the cutting blade actuator 751. The cutting blade actuator 751 is, for example, an air cylinder or an electric cylinder.

[0080] The fixed lower blade 702 is positioned below the movable upper blade 701 and in a position where it does not come into contact with the movable upper blade 701 during its vertical movement, so that it can cut the object to be cut between the movable upper blade 701 and the fixed lower blade 702 as the movable upper blade 701 moves up and down. As a result, the battery cell 2000 placed between the movable upper blade 701 and the fixed lower blade 702 can be cut by being sandwiched between the cutting edge of the movable upper blade 701 and the cutting edge of the fixed lower blade 702.

[0081] The lower end of the movable upper blade 701 is inclined relative to the upper end of the fixed lower blade 702. This reduces the contact area between the battery cell 2000 and the cutting edge of the lower end of the movable upper blade 701, thereby reducing cutting resistance. The lower end of the movable upper blade 701 may also be parallel to the upper end of the fixed lower blade 702. Furthermore, the lower end of the movable upper blade 701 may be curved.

[0082] The slide unit 602 has a slide actuator 752. The slide actuator 752 is an air cylinder or an electric slider, etc. The cutting unit 601 is mounted on the slide drive portion of the slide actuator 752, and the cutting unit 601 is configured to be movable by the slide actuator 752 in a direction parallel to the longitudinal direction of the cutting blade 700. In other words, the slide drive portion of the slide actuator 752 is driven in a direction parallel to the longitudinal direction of the cutting blade 700. The longitudinal direction of the cutting blade 700 is the direction in which the movable upper blade 701 and the fixed lower blade 702 extend, and is, for example, perpendicular to the thickness direction of the movable upper blade 701 and intersects (for example perpendicular to) the vertical movement direction of the movable upper blade 701. Also, if the movable upper blade 701 is a long plate-like shape with the cutting edge positioned at the short end of the movable upper blade 701, as shown in the figure, the longitudinal direction is the longitudinal direction of the movable upper blade 701.

[0083] The support unit 753 is, for example, a base for supporting the battery cell 2000, positioned in front of or behind the cutting unit 601 and the slide unit 602. The battery cell 2000 to be cut is held on the upper surface of the support unit 753. The battery cell 2000 may be fixed and held to the support unit 753 by a jig or the like (not shown). The battery cell 2000 is held such that the movable upper blade 701 is positioned above the main surface of the battery cell 2000. Also, a portion of the battery cell 2000 rests on the fixed lower blade 702. The height of the upper surface of the support unit 753 is the same as the height of the upper end of the fixed lower blade 702, and the battery cell 2000 is held such that the direction of vertical movement of the movable upper blade 701 is parallel to the thickness direction of the battery cell 2000. For example, the battery cell 2000 is held so that the main surface of the battery cell 2000 is horizontal. This makes it less likely for the battery cell 2000 to shift when it is cut, thus improving the accuracy of the cut.

[0084] The support unit 753 is not connected to the slide actuator 752 and its position is fixed. Therefore, the battery cell 2000 held by the support unit 753 does not move even when driven by the slide actuator 752.

[0085] The cutting blade actuator 751 and the slide actuator 752 are linked, for example, based on position sensor signals or drive pulse information, and the cutting blade 700 cuts the battery cells 2000 held by the support unit 753 while sliding in the longitudinal direction of the cutting blade 700. Alternatively, the support unit 753 may be used to hold multiple stacked battery cells 2000, allowing multiple battery cells 2000 to be cut at once.

[0086] Specifically, as shown in Figure 3C, when cutting a battery cell 2000, the movable upper blade 701 is moved by the cutting blade actuator 751 in the direction indicated by arrow M1. The direction indicated by arrow M1 is, for example, parallel to the thickness direction of the battery cell 2000. At the same time, the entire cutting unit 601, including the movable upper blade 701, is moved by the slide actuator 752 in one of the directions indicated by arrow M2. The direction indicated by arrow M2 is the longitudinal direction of the cutting blade 700. As a result, during the cutting process, the cutting blade 700 is slid in the longitudinal direction of the cutting blade 700, and the battery cell 2000 is cut downwards from above the main surface of the battery cell 2000 by the movable upper blade 701 of the cutting blade 700. In this case, the relative direction of movement of the movable upper blade 701 of the cutting blade 700 with respect to the battery cell 2000 during the cutting process is inclined with respect to the thickness direction of the battery cell 2000 when the cut surface formed when the battery cell 2000 is cut by the cutting blade 700 is viewed from above. As a result, a slit-like cut mark 800 inclined with respect to the thickness direction of the battery cell 2000 can be formed on the formed cut surface. Note that cutting downwards means cutting the battery cell 2000 by moving the cutting edge of the movable upper blade 701 toward the battery cell 2000. Therefore, when cutting downwards, for example, the movable upper blade 701 moves vertically downwards, but depending on the relative positional relationship between the movable upper blade 701 and the battery cell 2000, it does not necessarily move vertically downwards.

[0087] The relative direction of movement of the movable upper blade 701 with respect to the battery cell 2000 is a combined direction of either the direction indicated by arrow M1 or the direction indicated by arrow M2. For example, when the movable upper blade 701 moves in the direction of arrow M1, and at the same time the entire cutting unit 601 slides to the left in the direction indicated by arrow M2 in Figure 3C, a slanted cut mark 800 is formed in the direction shown in Figure 1. Also, when the entire cutting unit 601 does not slide, and the battery cell 2000 is cut only by the movable upper blade 701 moving in the direction of arrow M1, a slanted cut mark 800X is formed as shown in Figure 2.

[0088] As shown in Figure 3C, when the lower end of the movable upper blade 701 is inclined, the stroke of the movable upper blade 701 can be reduced by sliding the entire cutting unit 601 from the side of the lower end of the movable upper blade 701 closer to the support unit 753 to the side further away, that is, sliding to the left in the direction indicated by arrow M2 in Figure 3C. In addition, the load on the battery cell 2000 when the movable upper blade 701 is cut can be reduced by sliding the entire cutting unit 601 from the side of the lower end of the movable upper blade 701 further away from the support unit 753 to the side further away, that is, sliding to the right in the direction indicated by arrow M2 in Figure 3C.

[0089] Furthermore, when cutting the battery cell 2000, the angle difference between the thickness direction of the battery cell 2000 and the grooved cut mark 800 can be changed by setting the cutting speed of the cutting blade actuator 751 and the sliding speed of the slide actuator 752. The cutting speed is the speed at which the movable upper blade 701 cuts down on the battery cell 2000, and the sliding speed is the speed at which the cutting blade 700 slides in the length direction of the cutting blade 700. In addition, by changing the relationship between the cutting speed and the sliding speed during the cutting of the battery cell 2000 in the speed settings of the cutting blade actuator 751 and the slide actuator 752, it is also possible to make the grooved cut mark 800 curved. For example, the relationship between the cutting speed and the sliding speed can be changed by accelerating the cutting speed or sliding speed at the start of cutting the battery cell 2000, or by decelerating the cutting speed or sliding speed before the end of cutting the battery cell 2000. Furthermore, during the cutting of the battery cell 2000, the relationship between the cutting speed and the sliding speed may be changed by continuously accelerating or decelerating the cutting speed or the sliding speed.

[0090] Another advantage of manufacturing the battery 1000 by having the cutting blade actuator 751 and the slide actuator 752 cooperate based on their respective positional information to create an angular difference between the groove-shaped cut marks 800 and the thickness direction of the battery cell 2000 is that the cutting load is reduced, thereby improving the reliability of the battery 1000.

[0091] Specifically, in the cutting process, the cutting blade 700 is slid along its length while the movable upper blade 701 of the cutting blade 700 cuts down on the battery cell 2000. Therefore, the cutting resistance can be reduced because the battery cell 2000 is cut not only by being pushed through, but also by the cutting edge of the movable upper blade 701 sliding across it. As a result, the stress applied to the battery cell 2000 during cutting is reduced, which reduces the risk of damage such as microcracks occurring inside the battery cell 2000 near the cut surface due to stress, thereby improving the reliability of the battery 1000.

[0092] In the above method for cutting the battery cell 2000, the cutting blade 700 was slid in the longitudinal direction of the cutting blade 700, but this is not the only method. In the cutting process, the battery cell 2000 may be cut down by the movable upper blade 701 of the cutting blade 700 while the battery cell 2000 is slid in the longitudinal direction of the cutting blade 700. Figure 4 is a diagram illustrating another example of the movement of the cutting device 600. In the cutting device 600 shown in Figures 3A and 3B, the cutting unit 601 slid and the support unit 753 was fixed, but Figure 4 shows a case in the cutting device 600 where the cutting unit 601 is fixed and the support unit 753 slides. In other words, the support unit 753 may be connected to a slide actuator 752 and driven by the slide actuator 752.

[0093] As shown in Figure 4, when cutting the battery cell 2000, the movable upper blade 701 moves in the direction indicated by arrow M1 by the cutting blade actuator 751. At the same time, the support unit 753 moves in one of the directions indicated by arrow M3 by the slide actuator 752. The direction indicated by arrow M3 is the longitudinal direction of the cutting blade 700. As a result, during the cutting process, the battery cell 2000 held by the support unit 753 is slid in the longitudinal direction of the cutting blade 700, and the battery cell 2000 is cut downward from above the main surface of the battery cell 2000 by the movable upper blade 701 of the cutting blade 700. As a result, a slit-like cut mark 800 that is inclined with respect to the thickness direction of the battery cell 2000 can be formed on the cut surface. For example, as the movable upper blade 701 moves in the direction of arrow M1, the battery cell 2000 held by the support unit 753 slides to the right in the direction indicated by arrow M3 in Figure 4, thereby forming a groove-shaped cut mark 800 that is inclined in the direction shown in Figure 1. This method also reduces the cutting resistance when cutting the battery cell 2000. In this case, the sliding speed is the speed at which the battery cell 2000 slides along the length of the cutting blade 700.

[0094] Furthermore, during the cutting process, the battery cell 2000 may be held such that its main surface is inclined with respect to the length direction of the cutting blade 700. In this case, since the thickness direction of the battery cell 2000 is inclined with respect to the direction of movement of the movable upper blade 701, the relative direction of movement of the movable upper blade 701 of the cutting blade 700 with respect to the battery cell 2000 is inclined with respect to the thickness direction of the battery cell 2000 when the cut surface formed when the battery cell 2000 is cut by the cutting blade is viewed from above. Therefore, without using a slide actuator 752, a groove-like cut mark 800 that is inclined with respect to the thickness direction of the battery cell 2000 can be formed simply by cutting down on the battery cell 2000 with the movable upper blade 701 of the cutting blade 700.

[0095] [Differentiation] Next, a modified example of Embodiment 1 will be described. In the following description of the modified example, the differences from Embodiment 1 will be the main focus, and the similarities will be omitted or simplified.

[0096] Figure 5 is a side view showing the schematic configuration of the battery 1010 in a modified example of Embodiment 1. Figure 5 is a plan view of the side of the battery 1010. Also, Figure 5 is a plan view of the side of the battery cell 2000 provided in the battery 1010.

[0097] As shown in Figure 5, the modified battery 1010 of Embodiment 1 differs from the battery 1000 of Embodiment 1 in that the side surface of the battery cell 2000 has a striated cut mark 801 instead of a striated cut mark 800.

[0098] In the battery 1010, the side surface of the battery cell 2000 is a cut surface formed by cutting in one piece, and the side surface of the battery cell 2000 is provided with a striated cut mark 801, which is an example of a striated recess or protrusion. When the side surface of the battery cell 2000 is viewed from above, the striated cut mark 801 is curved. In the example shown in Figure 5, the striated cut mark 801 is curved overall, but it may have both straight and curved portions. In addition, at least a portion of the striated cut mark 801 is inclined with respect to the thickness direction of the battery cell 2000 when the side surface of the battery cell 2000 is viewed from above. In the example shown in Figure 5, the striated cut mark 801 is inclined with respect to the thickness direction of the battery cell 2000 in all parts.

[0099] In the example shown in Figure 5, the striated cut mark 801 is curved so that the lower side is convex, but it may also be curved so that the upper side is convex. Furthermore, the striated cut mark 801 may have a portion that is curved so that the lower side is convex and a portion that is curved so that the upper side is convex.

[0100] When the side surface of the battery cell 2000 is viewed from above, the angle between the straight line connecting the ends of the groove-like cut marks 801 and the thickness direction of the battery cell 2000 is, for example, 18 degrees or more and 84 degrees or less, and may also be 25 degrees or more and 78 degrees or less.

[0101] In battery 1010, the grooved cut marks 801 are curved, so compared to the case where they are not curved, the grooved cut marks 801 between the negative electrode current collector 210 or negative electrode active material layer 110 and the positive electrode current collector 220 or positive electrode active material layer 120 are longer. In other words, the distance between the portion of the grooved cut marks 801 located on the negative electrode current collector 210 or negative electrode active material layer 110 and the portion located on the positive electrode current collector 220 or positive electrode active material layer 120, where the electric field is likely to concentrate, becomes longer. Therefore, by suppressing the occurrence of edge discharge on the side surface of the battery cell 2000, the occurrence of short circuits is suppressed, and a more reliable battery 1010 can be realized.

[0102] The striated cut marks 801 are formed, for example, in the cutting process described above, by changing the relationship between the cutting speed and the sliding speed during the cutting of the battery cell 2000, in the speed settings of the cutting blade actuator 751 and the slide actuator 752. In other words, the relative direction of movement of the movable upper blade 701 of the cutting blade 700 with respect to the battery cell 2000 during the cutting process changes while the battery cell 2000 is being cut.

[0103] (Embodiment 2) Next, Embodiment 2 will be described. In the following description of Embodiment 2, the differences from Embodiment 1 will be the main focus, and the similarities will be omitted or simplified. The battery in Embodiment 2 is a stacked battery in which multiple battery cells are stacked.

[0104] Figure 6 is a schematic side view showing the general configuration of the battery 1100 in Embodiment 2. Figure 6 is a plan view of the side of the battery 1100. Figure 6 is also a plan view of the same side of the multiple battery cells 2000, 2000a, 2000b, and 2000c provided in the battery 1100.

[0105] As shown in Figure 6, the battery 1100 in Embodiment 2 comprises a plurality of battery cells 2000, 2000a, 2000b, and 2000c, including the battery cell 2000 provided in the battery 1000 in Embodiment 1. The plurality of battery cells 2000, 2000a, 2000b, and 2000c are stacked.

[0106] Battery 1100 has a structure in which multiple battery cells 2000, 2000a, 2000b, and 2000c are electrically connected in parallel and stacked. Battery 1100 is a parallel stacked battery in which multiple battery cells 2000, 2000a, 2000b, and 2000c are integrated by adhesive or bonding. Specifically, adjacent battery cells in the multiple battery cells 2000, 2000a, 2000b, and 2000c are stacked in a reversed stacking order for each layer. The negative electrode current collectors 210 and positive electrode current collectors 220 of the multiple battery cells 2000, 2000a, 2000b, and 2000c are electrically connected by leads (not shown), thereby connecting the multiple battery cells 2000, 2000a, 2000b, and 2000c in parallel. The leads connecting the current collectors are connected to, for example, the extraction electrodes.

[0107] Each of the battery cells 2000, 2000a, 2000b, and 2000c comprises a negative electrode active material layer 110, a solid electrolyte layer 130, and a positive electrode active material layer 120, and may further comprise at least one of a negative electrode current collector 210 and a positive electrode current collector 220. Specifically, battery cell 2000 comprises a negative electrode current collector 210, a negative electrode active material layer 110, a solid electrolyte layer 130, a positive electrode active material layer 120, and a positive electrode current collector 220. Also, battery cells 2000a and 2000c each comprise a negative electrode active material layer 110, a solid electrolyte layer 130, a positive electrode active material layer 120, and a positive electrode current collector 220. Furthermore, battery cell 2000b comprises a negative electrode current collector 210, a negative electrode active material layer 110, a solid electrolyte layer 130, and a positive electrode active material layer 120. Battery cells 2000a, 2000b, and 2000c each share a current collector, with the negative electrode current collector 210 or positive electrode current collector 220 of an adjacent battery cell being in contact with the negative electrode active material layer 110 or positive electrode active material layer 120. However, multiple battery cells 2000, 2000a, 2000b, and 2000c may not share a current collector, and all battery cells may comprise a negative electrode current collector 210, a negative electrode active material layer 110, a solid electrolyte layer 130, a positive electrode active material layer 120, and a positive electrode current collector 220.

[0108] Various methods can be used to extract electrodes from the battery 1100, such as end terminals, upper and lower end terminals, or current collection tabs.

[0109] Each of the battery cells 2000, 2000a, 2000b, and 2000c in the battery 1100 has a striated cut mark 810 on its side surface, which is a striated recess or protrusion resulting from the aforementioned cutting process that cuts the battery cells 2000, 2000a, 2000b, and 2000c. When the side surface of the battery cells 2000, 2000a, 2000b, and 2000c is viewed from above, the striated cut mark 810 is inclined with respect to the thickness direction of the battery cells 2000, 2000a, 2000b, and 2000c. Each of the side surfaces of the battery cells 2000, 2000a, 2000b, and 2000c is a cut surface formed by the aforementioned cutting process. Among the multiple battery cells 2000, 2000a, 2000b, and 2000c, the striated cut marks 810 on adjacent battery cells are continuous and form a single line. The striated cut marks 810 are provided across the sides of each adjacent battery cell among the multiple battery cells 2000, 2000a, 2000b, and 2000c. In the example shown in Figure 6, there are also striated cut marks 810 that are continuous across all sides of the multiple battery cells 2000, 2000a, 2000b, and 2000c. The striated cut marks 810 do not have to extend to the edge of the battery 1100, and may be interrupted midway along the sides of the multiple battery cells 2000, 2000a, 2000b, and 2000c.

[0110] The striated cut marks 810 are formed when multiple battery cells 2000, 2000a, 2000b, and 2000c are cut together in a stacked state during the cutting process. Therefore, the manufacturing process of the battery 1100 can be simplified.

[0111] Furthermore, a stacked battery like battery 1100 is not limited to a parallel stacked battery, but may also be a series stacked battery. Figure 7 is a schematic side view showing the general configuration of another battery 1110 in Embodiment 2. Battery 1110 comprises a plurality of battery cells 2000. Battery 1110 has a structure in which a plurality of battery cells 2000 are electrically connected in series and stacked. Battery 1110 is a series stacked battery in which a plurality of battery cells 2000 are integrated by bonding or joining. Specifically, the plurality of battery cells 2000 are stacked so that the stacking order of each layer is the same. As a result, the plurality of battery cells 2000 are electrically connected in series. For example, extraction electrodes are connected to the negative electrode current collector 210 and the positive electrode current collector 220 that constitute the main surface of battery 1110, respectively.

[0112] In battery 1110, as in battery 1100, each of the multiple battery cells 2000 has a groove-like cut mark 810 on its side surface, which is inclined with respect to the thickness direction of the multiple battery cells 2000 when the side surface of the multiple battery cells 2000 is viewed from above.

[0113] Furthermore, the grooved cut marks provided in the stacked battery do not have to be continuous in adjacent battery cells. Grooved cut marks may be formed by cutting one or more of the battery cells together. Figure 8 is a schematic side view showing the schematic configuration of yet another battery 1120 in Embodiment 2. Battery 1120 is a parallel stacked battery in which multiple battery cells 2000, 2000a, 2000b, and 2000c are stacked, similar to battery 1100. Battery 1120 is provided with grooved cut marks 820a and grooved cut marks 820b instead of grooved cut marks 810 in battery 1100.

[0114] Among the multiple battery cells 2000, 2000a, 2000b, and 2000c, a groove-like cut mark 820a is provided on the side surface of one adjacent battery cell, and a groove-like cut mark 820b is provided on the side surface of the other battery cell. The groove-like cut marks 820a and 820b are not continuous. When viewing the sides of the multiple battery cells 2000, 2000a, 2000b, and 2000c from a plan view, the groove-like cut marks 820a and 820b are in opposite directions relative to the thickness direction of the multiple battery cells 2000, 2000a, 2000b, and 2000c. For example, in the plane of Figure 8, the groove-like cut mark 820a provided on battery cell 2000b is inclined downward to the right, and the groove-like cut mark 820b provided on battery cell 2000c is inclined downward to the left, in the opposite direction to the downward slope to the right. Thus, in the battery 1120, multiple battery cells 2000, 2000a, 2000b, and 2000c are stacked such that the striated cut marks 820a and 820b alternate on the sides of each of the multiple battery cells 2000, 2000a, 2000b, and 2000c. In other words, the striated cut marks 820a and 820b are zigzag on the sides of the multiple battery cells 2000, 2000a, 2000b, and 2000c. As a result, even if the battery 1120 is subjected to impact or other forces, damage to the battery 1120 originating from the striated cut marks 820a and 820b is less likely to propagate, thereby improving the reliability of the battery 1120.

[0115] In the battery 1120, a cut surface is formed in the cutting process by individually cutting multiple battery cells 2000, 2000a, 2000b, and 2000c together. The battery 1120 is formed by stacking the multiple battery cells 2000, 2000a, 2000b, and 2000c that have been individually cut together. In this process, for example, battery cells 2000 and 2000b are cut in such a way that striated cut marks 820a are formed, and battery cells 2000a and 2000c are cut in such a way that striated cut marks 820b are formed.

[0116] (Other embodiments) The batteries relating to this disclosure have been described above based on embodiments and modifications, but this disclosure is not limited to these embodiments and modifications. Within the scope of this disclosure, various modifications to the embodiments and modifications that a person skilled in the art could conceive of, as long as they do not depart from the spirit of this disclosure, as well as other forms constructed by combining some of the components of the embodiments and modifications, are also included.

[0117] Furthermore, the above embodiments and variations may be modified, replaced, added, omitted, etc., within the scope of the claims or their equivalents. [Industrial applicability]

[0118] The battery described herein can be used as a battery for electronic devices, electrical appliances, electric vehicles, and the like. [Explanation of Symbols]

[0119] 110 Negative electrode active material layer 120 Cathode active material layer 130 Solid electrolyte layer 210 Negative electrode current collector 220 Positive electrode current collector 600 cutting equipment 601 Cutting Unit 602 Slide Unit 700 cutting blade 701 Movable upper blade 702 Fixed lower blade 751 Cutting blade actuator 752 Slide Actuator 753 Support Unit 800, 801, 810, 820a, 820b striated cuts 1000, 1010, 1100, 1110, 1120 batteries 2000, 2000a, 2000b, 2000c battery cells

Claims

1. Equipped with at least one battery cell, The at least one battery cell comprises a positive electrode active material layer, a negative electrode active material layer, a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, a positive electrode current collector facing the solid electrolyte layer via the positive electrode active material layer, and a negative electrode current collector facing the solid electrolyte layer via the negative electrode active material layer. On the side surface of the at least one battery cell, the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte layer, the positive electrode current collector, and the negative electrode current collector are exposed. On the side surface of the at least one battery cell, when the side surface of the at least one battery cell is viewed from above, a groove-like recess or protrusion is provided that is inclined with respect to the thickness direction of the at least one battery cell, connecting the positive electrode current collector and the negative electrode current collector. battery.

2. When the side surface of at least one of the battery cells is viewed from above, the angle between the striated recess or protrusion and the thickness direction is 18 degrees or more and 84 degrees or less. The battery according to claim 1.

3. When the side surface of at least one of the battery cells is viewed from above, the angle between the striated recess or protrusion and the thickness direction is 25 degrees or more and 78 degrees or less. The battery according to claim 1.

4. When the side surface of the at least one battery cell is viewed from above, the striated recess or protrusion is curved. The battery according to any one of claims 1 to 3.

5. The depth of the recess or the height of the protrusion in the aforementioned groove-like recess or protrusion is 0.1 μm or more. The battery according to any one of claims 1 to 4.

6. The aforementioned at least one battery cell is a plurality of battery cells, The aforementioned multiple battery cells are stacked, The battery according to any one of claims 1 to 5.

7. The groove-like recesses or protrusions in each of the adjacent battery cells among the plurality of battery cells are continuous. The battery according to claim 6.

8. The groove-like recesses or protrusions in each of the adjacent battery cells among the plurality of battery cells are in opposite directions relative to the thickness direction when the side surfaces of the adjacent battery cells are viewed from above. The battery according to claim 6.

9. A method for manufacturing a battery, The process includes a cutting step of cutting a laminate having a positive electrode active material layer, a negative electrode active material layer, a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, a positive electrode current collector facing the solid electrolyte layer via the positive electrode active material layer, and a negative electrode current collector facing the solid electrolyte layer via the negative electrode active material layer, with a cutting blade to form a cut surface in which the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte layer, the positive electrode current collector, and the negative electrode current collector are exposed. In the cutting process, the laminate and at least one of the cutting blade are slid in the longitudinal direction of the cutting blade, and the laminate is cut downward with the cutting blade, thereby forming groove-like recesses or protrusions on the cut surface that are inclined with respect to the thickness direction of the laminate and connect the positive electrode current collector and the negative electrode current collector. Battery manufacturing method.

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