Solid-state battery cell, method for manufacturing solid-state battery cell, inspection method, inspection device, inspection program, and method for manufacturing solid-state battery module

Abstract

This solid-state battery cell comprises: an electrode laminate that has an electrolyte layer containing a solid electrolyte; and a laminate exterior body that accommodates the electrode laminate. Both surfaces of the electrode laminate in the lamination direction are defined as main surfaces, respectively. The laminate exterior body has a contour identification protrusion provided at a position corresponding to the outer peripheral ends of the main surfaces of the electrode laminate.

Description

Solid battery cell, method for manufacturing solid battery cell, inspection method, inspection apparatus, inspection program, and method for manufacturing solid battery module

[0008] ,

[0001] The present invention relates to a solid battery cell, a method for manufacturing a solid battery cell, an inspection method, an inspection apparatus, and a method for manufacturing a solid battery module.

[0002] A secondary battery (hereinafter referred to as a solid battery) having an electrode laminate containing a solid electrolyte is known. The solid battery may be provided as a laminate cell (hereinafter sometimes referred to as a solid battery cell) in which the electrode laminate is housed in a laminate exterior body.

[0003] In the solid battery cell, it is preferable that the inside of the laminate exterior body is sealed. However, defects may occur in the laminate exterior body. Therefore, a technique capable of inspecting for defects is required.

[0004] In relation to the above, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2022-095089) discloses a technique aimed at providing an all-solid-state lithium-ion secondary battery capable of quickly and easily performing a leak inspection. Patent Document 1 describes that a predetermined inspection recess or a predetermined inspection protrusion is formed on the surface of the exterior film along the recess formed on the surface side of the solid battery.

[0005] Japanese Unexamined Patent Application Publication No. 2022-095089

[0006] It is desirable that the inspection of defects be carried out in a short time. Therefore, an object of the present invention is to provide a technique capable of inspecting for the presence or absence of defects in the laminate exterior body of a solid battery cell in a short time.

[0007] In one aspect, a solid battery cell according to the present invention includes an electrode laminate having an electrolyte layer containing a solid electrolyte, and a laminate exterior body that houses the electrode laminate. Both surfaces of the electrode laminate in the stacking direction are defined as main surfaces. The laminate exterior body has a convex portion for contour identification provided at a position corresponding to the outer peripheral end of the main surface of the electrode laminate.

[0008] In one embodiment, the method for manufacturing a solid-state battery cell according to the present invention is a method for manufacturing the solid-state battery cell described above. The laminate casing includes a pair of laminate films. This manufacturing method comprises the steps of arranging an electrode stack between the pair of laminate films, sealing the pair of laminate films together on the side of the electrode stack to form a sealed portion, and, after the step of forming the sealed portion, exhausting the space inside the laminate casing. The step of forming the sealed portion includes sealing the pair of laminate films together such that an excess space is formed on the side of the electrode stack. The excess space is a space of such size that a protrusion for contour identification is formed after the exhaust step.

[0009] In one embodiment, the inspection method according to the present invention comprises the steps of: imaging the above-mentioned solid battery cell and acquiring imaging data; identifying a protrusion for contour identification based on the imaging data; and determining whether the solid battery cell is good or bad based on the identification result of the identification step.

[0010] In one embodiment, the inspection program according to the present invention is an inspection program for implementing the above-described inspection method using a computer.

[0011] In one embodiment, the inspection apparatus according to the present invention comprises an imaging unit that images the solid battery cell and generates imaging data, an identification unit that identifies the position of a protrusion for contour identification based on the imaging data, and an inspection unit that determines whether the solid battery cell is good or bad based on the identification result of the identification unit.

[0012] In one embodiment, the method for manufacturing a solid-state battery module according to the present invention comprises the steps of: imaging the solid-state battery cell and generating imaging data; identifying the position of a protrusion for contour identification based on the imaging data; determining the stacking position when stacking a plurality of solid-state battery cells based on the identification result of the identification step; and stacking the plurality of solid-state battery cells based on the determined stacking position.

[0013] Figure 1 is a schematic cross-sectional view showing a solid battery cell according to an embodiment. Figure 2 is a schematic plan view showing a solid battery cell. Figure 3 is a cross-sectional view showing an enlarged view of the configuration at the corner of a solid battery cell. Figure 4A shows a good solid battery cell. Figure 4B shows a defective solid battery cell. Figure 5 is a schematic diagram showing a method for manufacturing a solid battery cell according to an embodiment. Figure 6 is a schematic cross-sectional view showing the configuration of a solid battery cell before and after the exhaust process according to a reference example. Figure 7 is a schematic cross-sectional view showing the configuration after the sealing process (before the exhaust process) in Modification Example 1. Figure 8 is a schematic cross-sectional view showing the configuration after the sealing process (before the exhaust process) in Modification Example 2. Figure 9 is a schematic cross-sectional view showing the configuration during the exhaust process in Modification Example 3. Figure 10 is a schematic diagram showing the functional configuration of a solid battery cell inspection device. Figure 11 is a flowchart showing a solid battery cell inspection method. Figure 12 is a flowchart showing an example of a specific operation method for the quality determination process. Figure 13 is a plan view showing an example of the shape of a protrusion. Figure 14 is a plan view for explaining the positional relationship between the laminate outer casing and the electrode stack. Figure 15A shows two solid-state battery cells stacked relative to the position of the laminated outer casing. Figure 15B shows two solid-state battery cells stacked relative to the position of the electrode stack. Figure 16 is a flowchart showing a method for manufacturing a solid-state battery module. Figure 17 is a block diagram showing the functional configuration of a control device for realizing a method for manufacturing a solid-state battery module.

[0014] Hereinafter, a solid-state battery cell according to an embodiment of the present invention will be described with reference to the drawings.

[0015] In this embodiment, "solid-state battery" refers to a secondary battery having an electrolyte layer containing a solid electrolyte. The electrolyte layer as a whole is solid. However, it is not necessary for all components contained in the electrolyte layer to be solid; liquid components may be used as part of the components of the electrolyte layer. In this embodiment, "solid-state battery" includes so-called "all-solid-state batteries." Furthermore, a cell has a structure in which an electrode stack is housed in a laminated outer casing.

[0016] (1) Solid-state battery cell Figure 1 is a schematic cross-sectional view showing a solid-state battery cell 1 according to the first embodiment. Note that Figure 1 is merely a schematic diagram, and the main parts of this embodiment are not shown. Figure 2 is a schematic plan view showing this solid-state battery cell 1.

[0017] As shown in Figures 1 and 2, the solid-state battery cell 1 has an electrode stack 2, a laminated outer casing 3, and a tab 4.

[0018] The electrode stack 2 is the part that realizes the charge and discharge function. The electrode stack 2 is housed within the laminate outer casing 3. The electrode stack 2 has an electrolyte layer containing a solid electrolyte. Although detailed illustrations are omitted, the electrode stack 2 has a laminated structure including an electrolyte layer and electrode layers (positive electrode layer and negative electrode layer). Also, although not shown in the illustrations, a current collector foil is connected to each electrode layer in the electrode stack 2. The current collector foil extends laterally from the electrode stack 2 and is connected to a tab 4.

[0019] Tab 4 is provided to electrically connect the electrode laminate 2 to an external device. One end of Tab 4 is located inside the laminate casing 3, and the other end is located outside the laminate casing 3.

[0020] As described above, the laminated outer casing 3 houses the electrode laminate 2. The laminated outer casing 3 is formed from a pair of laminated films (3-1 to 3-2). The electrode laminate 2 is sandwiched between the pair of laminated films (3-1 to 3-2). Each laminated film (3-1 to 3-2) has a structure in which, for example, an insulating resin film is laminated onto a metal film.

[0021] The pair of laminate films (3-1 to 3-2) are sealed at their outer periphery. Specifically, the pair of laminate films (3-1 to 3-2) are sealed on the side of the electrode stack 2. That is, the pair of laminate films (3-1 to 3-2) are bonded to each other on the side of the electrode stack 2. This seals the space inside the laminate outer casing 3. In the areas where tabs 4 are present, each laminate film (3-1 to 3-2) is bonded to tabs 4.

[0022] In this embodiment, the configuration of the laminate outer casing 3 in the contour portion of the electrode stack 2 has been improved. This will be explained with reference to Figure 3. Figure 3 is an enlarged cross-sectional view showing the configuration at the corner of the solid battery cell 1.

[0023] As shown in Figure 3, the laminated outer casing 3 is provided with protrusions 5 for contour identification. Specifically, both sides of the electrode laminate 2 in the lamination direction are defined as main surfaces. The main surfaces are flat. The protrusions 5 are provided at positions corresponding to the outer periphery of the main surfaces. That is, the protrusions 5 are provided along the contour of the electrode laminate 2. As shown in Figure 2, the protrusions 5 are provided along the entire circumference of the outer periphery of the main surfaces of the electrode laminate 2. The protrusions 5 may be provided on each of the two main surfaces (i.e., both sides), or on only one of the main surfaces.

[0024] The above is a schematic configuration of the solid-state battery cell 1 according to this embodiment.

[0025] With the configuration described above, it is possible to inspect whether or not there are defects in the laminated outer casing 3 using the contour identification protrusion 5. This point will be explained with reference to Figures 4A and 4B.

[0026] Figure 4A shows a good solid-state battery cell 1. Figure 4A(a) shows a photograph of a solid-state battery cell 1 actually manufactured by the inventors. Figure 4A(b) is a schematic diagram showing the position of the protrusion 5 identified from the photograph. As shown in Figure 4A, in the case of a good product, the protrusion 5 is clearly observed along the contour of the electrode stack 2.

[0027] On the other hand, Figure 4B shows a defective solid-state battery cell 1. Figure 4B(a) shows a photograph of a solid-state battery cell 1 actually created by the inventors. Figure 4B(a) is a schematic diagram showing the position of the protrusion 5 identified from the photograph. As shown in Figure 4B, if there is a defect in the laminate casing 3, air or the like will enter the laminate casing 3. In this case, the laminate casing 3 will also deform at the protrusion 5, and the protrusion 5 will become unclear.

[0028] In other words, as shown in Figures 4A and 4B, there is a difference in the clarity of the protrusions 5 depending on whether or not there is a defect in the laminated outer casing 3. Therefore, after the solid battery cell 1 is manufactured, the presence or absence of defects can be checked by imaging the solid battery cell 1 and recognizing the protrusions 5 through image analysis or the like. Since it only requires imaging the appearance of the solid battery cell 1 and performing computer processing, the inspection can be performed in a short time. For example, according to the inventors' findings, conventional methods for checking for leaks by performing vacuuming require at least two minutes, whereas with this embodiment, the inspection can be performed in less than 10 seconds.

[0029] Furthermore, according to this embodiment, even if it is uncertain which part of the laminated outer casing 3 has a defect, it is possible to determine whether or not there is a defect (leakage area).

[0030] The size of the protrusion 5 should be such that it can be distinguished from other parts by image analysis or the like.

[0031] (2) Method for Manufacturing a Solid Battery Cell Next, the method for manufacturing the solid battery cell 1 according to this embodiment will be described. Figure 5 is a schematic diagram showing the method for manufacturing a solid battery cell according to this embodiment. The manufacturing method according to this embodiment includes a sealing step and an exhaust step. Each step will be described below.

[0032] (Sealing Process) In manufacturing a solid-state battery cell, first, an electrode stack 2 is placed between a pair of laminate films (3-1 and 3-2). Then, the pair of laminate films (3-1 and 3-2) are bonded together on the side of the electrode stack 2. At the portion where the tab 4 is sandwiched, each laminate film (3-1 and 3-2) is bonded to the tab 4. This seals the pair of laminate films (3-1 and 3-2).

[0033] Figure 5(a) shows the shape of the end of the solid battery cell 1 after sealing. As shown in Figure 5(a), the sealing portion of the pair of laminate films (3-1 and 3-2) is called the "sealing portion 7". The sealing portion 7 is formed around the entire circumference of the outer periphery of the pair of laminate films (3-1 and 3-2), except for the portion that serves as a passage for removing air in the next exhaust process.

[0034] Here, the pair of laminate films (3-1 and 3-2) are sealed such that an excess space 6 is formed on the side of the electrode laminate 2. This excess space 6 is a space for forming the protrusion 5 after the next exhaust step.

[0035] (Exhaust Process) Next, the exhaust process is carried out. Specifically, as shown in Figure 5(b), the space inside the laminate outer casing 3 is exhausted. As the space is exhausted, the excess space 6 becomes smaller. At this time, if the size of the excess space 6 before exhaust is of a certain size, each laminate film (3-1 and 3-2) will be left over, and the protrusions 5 will be formed.

[0036] The above describes the manufacturing method of the solid battery cell 1 according to this embodiment. According to the method described above, since the exhaust process is carried out with the excess space 6 formed, the protrusion 5 can be formed after the exhaust process.

[0037] The size of the excess space 6 should be such that the protrusion 5 is formed. Figure 6 is a schematic cross-sectional view showing the configuration of the solid battery cell 1 before and after the exhaust process according to a reference example. In the reference example shown in Figure 6, the size of the excess space 6 is not large enough to form the protrusion 5. If the excess space 6 is too small, as shown in Figure 6(b), there will be no excess in each laminate film (3-1 and 3-2) after the exhaust process. Therefore, the protrusion 5 for contour recognition will not be formed. In contrast, according to this embodiment shown in Figure 5, an excess space 6 of sufficient size is formed, so the protrusion 5 can be formed in conjunction with the exhaust.

[0038] Next, a more specific method for forming the protrusion 5 will be explained, with reference to a modified example.

[0039] (Modification 1) Figure 7 is a schematic cross-sectional view showing the configuration after the sealing process (before the exhaust process) in Modification 1 of this embodiment. As shown in Figure 7, the distance of the laminate film 3-1 from the outer peripheral edge of the main surface of the electrode laminate 2 (see position A in the figure) to the sealing portion 7 is defined as the first distance B. Here, the first distance B is set within the range expressed by the following formula: (Formula 1) Thickness of electrode laminate / 2 + (Thickness of laminate film × 2) < First distance B < Thickness of electrode laminate / 2 + (Thickness of laminate film × 3)

[0040] By the first distance B being within the range of the above formula 1, it is possible to secure a surplus space 6 of sufficient size for the formation of the protrusion 5 after exhaust. As a result, the protrusion 5 can be formed more reliably. Specifically, by the first distance B being greater than the lower limit of the above formula 1, a protrusion 5 of sufficient size can be formed. On the other hand, by the first distance B being smaller than the upper limit of the above formula 1, it is possible to prevent the protrusion 5 from becoming creased. If a crease is formed in the protrusion 5, the protrusion 5 hardens, and even if a leak is present, the shape of the protrusion 5 is less likely to change. As a result, it may become difficult to detect the leak. If the first distance B is smaller than the above upper limit, the protrusion 5 is less likely to become creased, and it becomes possible to inspect the leak more reliably.

[0041] In the example shown in FIG. 7, the configuration of one laminate film 3-1 has been described. Regarding the other laminate film 3-2, it may be configured to have a specific first distance B, similar to the laminate film 3-1, but it does not have to be so.

[0042] (Modified Example 2) FIG. 8 is a schematic cross-sectional view showing the configuration after the sealing process (before the evacuation process) in Modified Example 2 of the present embodiment. In this modified example, in addition to the sealing portion 7, a flat portion 8, a side surface portion 9, and a bent portion 10 are provided on the laminate film 3-1 in the sealing process.

[0043] The flat portion 8 is a portion disposed on the main surface of the electrode laminate 2. The flat portion 8 is a portion parallel to the main surface of the electrode laminate 2.

[0044] The side surface portion 9 is a portion provided outside the flat portion 8. The side surface portion 9 is also a portion covering the side surface of the electrode laminate 2.

[0045] The bent portion 10 is a portion where the laminate film 3-1 is bent by plastic deformation. The bent portion 10 is provided at the boundary portion between the flat portion 8 and the side surface portion 9. In this bent portion 10, the laminate film 3-1 is bent so that the side surface portion 9 bulges outward.

[0046] If the configuration as shown in FIG. 8 is adopted, due to the provision of the bent portion 10, the convex portion 5 is more likely to be formed after evacuation.

[0047] Further, in the example shown in FIG. 8, the outer peripheral end of the flat portion 8 (in other words, the bent portion 10) is located outside the outer peripheral end of the main surface of the electrode laminate 2. By adopting such a configuration, the laminate exterior 3 is less likely to peel off after evacuation. As a result, it becomes possible to more reliably form the convex portion 5.

[0048] [[ID=

[0049] (Modification Example 3) FIG. 9 is a schematic cross-sectional view showing the configuration during the exhaust process in Modification Example 3. In the example shown in FIG. 9, in the exhaust process, the laminate film 3-1 is pressed against the main surface of the electrode laminate 2. Specifically, in this modification example, the pressing member 11 is used. That is, the laminate film 3-1 is pressed against the main surface of the electrode laminate 2 by the pressing member 11. And in the state where the laminate film 3-1 is pressed against the main surface of the electrode laminate 2, the space inside the laminate exterior 3 is exhausted. According to such a configuration, the convex portion 5 is more likely to be formed. <000^00> (3) Inspection Apparatus and Inspection Method for Solid State Battery Cells Next, the inspection apparatus and inspection method for the solid state battery cell 1 will be described. As described above, the solid state battery cell 1 according to the present embodiment is provided with the convex portion 5 for contour identification. By using this convex portion 5, it is possible to inspect the quality of the solid state battery cell 1.

[0051] FIG. 10 is a schematic diagram showing the functional configuration of the inspection apparatus 20 for the solid state battery cell 1 according to the present embodiment. As shown in FIG. 10, the inspection apparatus 20 includes an imaging unit 21, an identification unit 22, and an inspection unit 23. The inspection apparatus 20 is realized by, for example, a computer. Specifically, the imaging unit 21, the identification unit 22, and the inspection unit 23 are realized by executing an inspection program stored in a storage device such as a ROM by an arithmetic device such as a CPU. <0000J04> FIG. 11 is a flowchart showing the inspection method for the solid state battery cell. This inspection method can be executed by, for example, the above-described inspection apparatus 20. As shown in FIG. 11, the inspection method includes an imaging step (step S1), a convex portion identification step (step S2), and a pass / fail determination step (step S3). The operations of each step will be described in detail below.

[0053] (Step S1) Imaging First, after the solid battery cell 1 is manufactured, the solid battery cell 1 is imaged. Specifically, the imaging unit 21 images the solid battery cell 1 using an imaging device (not shown) (for example, an optical camera). This yields imaging data showing an image like that shown in Figure 4A or Figure 4B. When imaging, an illumination device (not shown) may be used so that the convex portion 5 is emphasized. That is, the solid battery cell 1 may be imaged under illumination light. By performing imaging under illumination light, the illumination light is scattered at the convex portion 5, making the convex portion easier to identify in the next step. The imaging device may be a general-purpose optical imaging device.

[0054] (Step S2) Identification of the protrusions Next, the identification unit 22 identifies the position of the protrusions 5 based on the imaging data. During identification, the identification unit 22 may, if necessary, perform image processing on the imaging data to enhance the protrusions 5.

[0055] (Step S3) Quality Determination Next, the inspection unit 23 makes a quality determination based on the identification result of the protrusion 5 by the identification unit 22. The inspection unit 23 outputs the quality determination result via an output device (not shown).

[0056] Figure 12 is a flowchart showing an example of the specific operation method of the quality determination process (step S3). In this example, the quality determination process (step S3) includes a clarity determination process (S3-1), a process for determining the length of the protrusion (S3-2), and a process for determining the linearity of the protrusion (S3-3). Each process will be described below.

[0057] (Step S3-1) The clarity determination inspection unit 23 first determines the clarity of the protrusions 5. As explained with reference to Figures 4A and 4B, if there are no defects in the laminated outer casing 3, the protrusions 5 are clearly identifiable along the contour of the electrode laminate 2. Therefore, by evaluating the clarity, it is possible to determine whether or not there are leaks. This makes it possible to determine whether or not the product is good. If a defect is determined in this step, information indicating that the product is defective from the perspective of leaks may be output.

[0058] (Step S3-2) Determination of the length of the protrusion Next, the inspection unit 23 determines the length of the protrusion 5. Figure 13 is a plan view showing an example of the shape of the protrusion 5. Figure 13(a) shows a good product, and Figure 13(b) shows a defective product. As shown in Figure 13(a), in a good product, the protrusion 5 is formed along the contour of the electrode stack 2. Therefore, the length (around the circumference) of the protrusion 5 corresponds to the length of the contour of the electrode stack 2 and becomes a predetermined value. On the other hand, if the main surface of the electrode stack 2 is not smooth, the protrusion 5 is formed inside the contour of the electrode stack 2, as shown in Figure 13(b). In the exhaust process, the laminate outer casing 3 adheres closely to the main surface of the electrode stack 2. At this time, if there are irregularities on the main surface of the electrode stack 2, the laminate outer casing 3 will adhere closely to these irregularities, and the area of ​​the contact portion will become smaller. Therefore, the protrusion 5 is formed inside the outer edge of the electrode stack 2. As a result, the length of the protrusion 5 will be different from the length of the contour of the electrode stack 2. Therefore, by comparing the length of the protrusion 5 with a preset length, it is possible to determine whether or not the protrusion 5 is formed along the contour of the electrode stack 2, and the smoothness of the main surface of the electrode stack 2 can be determined. This allows for the quality of the solid battery cell 1 to be determined. If a defect is determined in this step, information indicating that it is defective from the standpoint of smoothness may be output.

[0059] Furthermore, the smoothness of the electrode stack 2 is important from the viewpoint of battery characteristics. Specifically, solid-state battery cells 1 are often stacked in multiples and provided as a solid-state battery module. The solid-state battery module is pressurized to be compressed with extremely high pressure in the stacking direction in order to obtain good charge and discharge characteristics. If the surface of each solid-state battery cell 1 is not smooth, in-plane pressure variations will occur, making it difficult to obtain good charge and discharge characteristics. Therefore, it is important to evaluate the smoothness of the main surface of the electrode stack 2. According to this embodiment, the smoothness of the surface of the solid-state battery cell 1 can be indirectly evaluated by the length of the protrusions 5, so the quality of the solid-state battery cell 1 can also be determined from the viewpoint of smoothness.

[0060] (Step S3-3) Determination of the linearity of the protrusion Next, the inspection unit 23 determines the linearity of the protrusion 5. The electrode stack 2 is normally polygonal when viewed along the stacking direction, and each side is straight. Therefore, if the protrusion 5 is formed along the contour of the electrode stack 2, the protrusion 5 will also be straight. On the other hand, as explained in step S3-2, if the surface of the solid battery cell 1 is not smooth, the protrusion 5 will no longer correspond to the contour of the electrode stack 2. As a result, the protrusion 5 will be non-linear. Therefore, the linearity of the protrusion 5 also reflects the smoothness of the surface of the solid battery cell 1. By comparing the linearity of the protrusion 5 with a preset value, it is possible to indirectly determine whether or not the surface of the solid battery cell 1 is smooth. In this way, the smoothness of the solid battery cell 1 can be evaluated from a different viewpoint than in step S3-2, and a pass / fail judgment can be made. If a defect is determined in this step, information indicating that it is defective from the viewpoint of smoothness may be output.

[0061] As described above, according to this embodiment, the quality of the solid battery cell 1 can be determined based on the identification result of the protrusion 5. Note that steps S3-1 to S3-3 described above are merely examples. Therefore, all of steps S3-1 to S3-3 may be performed, or only some of steps S3-1 to S3-3 may be performed. Furthermore, the order of steps S3-1 to S3-3 may be changed.

[0062] (4) Method for manufacturing a solid battery module The solid battery cell 1 according to this embodiment is usually stacked in multiples and provided as a solid battery module. In this embodiment, the above-mentioned protrusions 5 can be used to determine the stacking position when stacking multiple solid battery cells 1.

[0063] Figure 14 is a plan view illustrating the positional relationship between the laminate casing 3 and the electrode stack 2 in the solid-state battery cell 1. As previously described, the electrode stack 2 is housed within the laminate casing 3. In the example shown in Figure 14(a), the electrode stack 2 is positioned such that each side of the electrode stack 2 is parallel to each side of the laminate casing 3. However, the electrode stack 2 is not always housed in the arrangement shown in Figure 14(a). For example, as shown in Figure 14(b), each side of the electrode stack 2 may be offset from each side of the laminate casing 3.

[0064] Figure 15A is a plan view showing the stacked state of the two solid-state battery cells 1 shown in Figures 14(a) and 14(b). Normally, the position of the electrode stack 2 is not visible from the outside. Therefore, when stacking multiple solid-state battery cells 1, the stacking position is determined based on the position of the laminate casing 3. Thus, in the example shown in Figure 15A, the two solid-state battery cells 1 are stacked based on the position of the laminate casing 3. In this case, as shown in Figure 15A, although the positions of the laminate casing 3 are aligned among the multiple solid-state battery cells 1, the positions of the electrode stack 2 may be misaligned. As previously described, the solid-state battery module is pressurized to compress it. If the positions of the electrode stack 2 are misaligned among the multiple solid-state battery cells 1, the pressure applied to each solid-state battery cell 1 becomes uneven, which is undesirable.

[0065] On the other hand, Figure 15B shows two solid-state battery cells 1 stacked relative to the position of the electrode stack 2. It is preferable to stack multiple solid-state battery cells 1 so that the outer edges of the electrode stack 2 are aligned, because this will result in uniform pressure being applied to each solid-state battery cell 1.

[0066] In this embodiment, since the protrusions 5 are provided at positions corresponding to the contour of the electrode stack 2, the stacking positions of multiple solid-state battery cells 1 can be determined by utilizing these protrusions 5 so that the positions of the electrode stacks 2 are aligned.

[0067] For details, please refer to Figures 16 and 17. Figure 16 is a flowchart showing a method for manufacturing a solid-state battery module according to this embodiment. This method for manufacturing a solid-state battery module includes an imaging step (S1), a protrusion identification step (S2), a stacking position determination step (S4), and a stacking step (S5).

[0068] Figure 17 is a block diagram showing the functional configuration of a control device 25 for realizing the manufacturing method of this solid-state battery module. The control device 25 includes an imaging unit 21, an identification unit 22, and a stacking position control unit 24. The control device 25 is implemented, for example, by a computer. That is, the imaging unit 21, the identification unit 22, and the stacking position control unit 24 are implemented by executing a control program stored in a storage device such as ROM using a processing unit such as a CPU.

[0069] The operation in the imaging process (S1) and the protrusion identification process (S2), that is, the functional configuration of the imaging unit 21 and the identification unit 22, is the same as described in "(3) Inspection device and inspection method for solid battery cells" above. Specifically, in the imaging process (S1), imaging data of the solid battery cell 1 is generated by the imaging unit 21, and in the identification process (S2), the position of the protrusion 5 is identified by the identification unit 22.

[0070] After identifying the protrusions 5, in the stacking position determination step (S4), the stacking position control unit 24 determines the stacking position of the solid battery cell 1 based on the identification result of the protrusions 5 in the identification unit 22. For example, the stacking position control unit 24 obtains information such as dimensions and angles from the identification result of the protrusions 5, and determines the stacking position based on the obtained information.

[0071] Then, in the stacking process (S5), the stacking position control unit 24 sends information indicating the determined stacking position to the stacking device 26. The stacking device 26 stacks multiple solid battery cells 1 based on the determined stacking position. Specifically, other solid battery cells 1 are stacked on top of one solid battery cell 1 so that the positions of the identified protrusions 5 overlap in the stacking direction. This results in a solid battery module in which multiple solid battery cells are stacked.

[0072] By the method described above, multiple solid-state battery cells 1 are stacked so that the positions of the electrode stacks 2 are aligned, thereby obtaining a solid-state battery module. With this method, the multiple solid-state battery cells 1 are stacked based on the contour of the electrode stack 2 as shown in Figure 15B, rather than the laminate casing 3 as shown in Figure 15A. This makes it possible to make the pressure applied to each solid-state battery cell 1 uniform and prevents deterioration of charge and discharge characteristics due to stacking misalignment.

[0073] (Note) The following is a summary of representative embodiments included in this embodiment and their effects.

[0074] (Note 1) A solid-state battery cell comprising an electrode stack 2 having an electrolyte layer containing a solid electrolyte, and a laminate outer casing 3 housing the electrode stack, wherein both sides of the electrode stack 2 in the stacking direction are defined as main surfaces, and the laminate outer casing 3 has contour-identifying protrusions 5 provided at positions corresponding to the outer peripheral edges of the main surfaces of the electrode stack.

[0075] According to the above configuration, the protrusions 5 can be used to quickly inspect the laminated outer casing 3 for defects. Furthermore, when stacking multiple solid-state battery cells, the position of the protrusions 5 can be used to stack them using the electrode stack 2 as a reference.

[0076] (Note 2) A method for manufacturing a solid battery cell as described in Note 1, wherein the laminated outer casing 3 includes a pair of laminated films (3-1 to 3-2), and the manufacturing method comprises the steps of: arranging an electrode stack 2 between the pair of laminated films; sealing the pair of laminated films together on the side of the electrode stack to form a sealing portion 7; and, after the step of forming the sealing portion, exhausting the space inside the laminated outer casing 3, wherein the step of forming the sealing portion includes sealing the pair of laminated films together such that an excess space 6 is formed on the side of the electrode stack, and the excess space 6 is a space of such size that a protrusion 5 for contour identification is formed after the exhaust step, the method for manufacturing a solid battery cell.

[0077] According to the method described above, since excess space is formed before the exhaust process, the protrusions 5 can be formed along the contour of the electrode stack 2.

[0078] (Note 3) A method for manufacturing a solid-state battery cell as described in Note 2, wherein the distance of the laminate film 3-1 from the outer peripheral edge of the main surface of the electrode stack 2 to the sealing portion 7 is defined as the first distance B, and the step of forming the sealing portion includes forming the sealing portion 7 such that the first distance B is within the range represented by the following formula 1. (Formula 1) Thickness of electrode stack / 2 + (Thickness of laminate film × 2) < First distance < Thickness of electrode stack / 2 + (Thickness of laminate film × 3)

[0079] According to the method described above, a sufficiently large surplus space 6 is secured when forming the protrusion 5. In addition, the formation of folds in the protrusion 5 is prevented, making it easier to detect defects (leakage areas) in the laminated outer casing 3.

[0080] (Note 4) A method for manufacturing a solid battery cell as described in Note 2 or 3, wherein in the step of forming a sealing portion, the laminate film 3-1 has a flat portion 8 that is placed on the main surface of the electrode stack and a side portion 9 that is provided outside the flat portion and covers the side surface of the electrode stack, and the laminate film 3-1 is folded between the flat portion 8 and the side portion 9 such that the side portion 9 bulges outward between the flat portion 8 and the sealing portion 7.

[0081] According to the method described above, the convex portion 5 is more easily formed.

[0082] (Note 5) A method for manufacturing a solid battery cell as described in Note 4, wherein in the step of forming the sealing portion, the outer peripheral edge of the flat portion 8 is located outside the outer peripheral edge of the main surface of the electrode stack 2.

[0083] According to the method described above, the convex portion 5 is more easily formed.

[0084] (Note 6) A method for manufacturing a solid battery cell as described in any of Notes 2 to 5, wherein the exhaust step includes pressing a laminate film 3-1 against the main surface of the electrode stack 2, and exhausting the space inside the laminate outer casing 3 while the laminate film is pressed against the main surface of the electrode stack.

[0085] According to the method described above, the protrusions 5 are more easily formed. In addition, it is possible to prevent air from remaining between the main surface of the electrode laminate 2 and the laminate outer casing 3.

[0086] (Note 7) An inspection method comprising: a step of imaging the solid battery cell described in Note 1 and acquiring imaging data (S1); a step of identifying a protrusion for contour identification based on the imaging data (S2); and a step of determining whether the solid battery cell is good or bad based on the identification result of the identification step (S3).

[0087] According to the method described above, it is possible to inspect the laminate exterior 3 for defects in a short amount of time.

[0088] (Note 8) An inspection method for a solid battery cell as described in Note 7, wherein the step of determining whether the cell is good or bad (S3) includes a step of determining whether the solid battery cell is good or bad based on the clarity of the protrusions for contour identification (S3-1).

[0089] According to the method described above, by determining the clarity of the protrusions, it is possible to inspect whether or not there are leaks in the laminated outer casing 3.

[0090] (Note 9) An inspection method for a solid battery cell as described in Note 7 or 8, wherein the step of determining whether the solid battery cell is good or bad (S3) includes a step of determining whether the solid battery cell is good or bad based on the length of the identified contour identification protrusion (S3-2).

[0091] According to the method described above, by checking the length of the protrusions, it is possible to confirm whether or not the main surface (both sides in the stacking direction) of the solid battery cell is smooth.

[0092] (Note 10) A method for inspecting a solid battery cell as described in any of Notes 7 to 9, wherein the step of determining whether the solid battery cell is good or bad (S3) includes a step of determining whether the solid battery cell is good or bad based on the linearity of the identified contour identification protrusions.

[0093] According to the method described above, by utilizing the linearity of the convex portion, it is possible to confirm whether or not the main surface (both sides in the stacking direction) of the solid battery cell is smooth.

[0094] (Note 11) An inspection program for implementing any of the inspection methods described in Notes 7 to 10 using a computer.

[0095] The above-described inspection method can be achieved by having a computer execute the aforementioned inspection program.

[0096] (Note 12) An inspection device comprising: an imaging unit 21 that images the solid battery cell described in Note 1 and generates imaging data; an identification unit 22 that identifies the position of the protrusion for contour identification based on the imaging data; and an inspection unit 23 that determines whether the solid battery cell is good or bad based on the identification result of the identification unit.

[0097] According to the inspection device described above, it is possible to inspect for defects in the solid-state battery cell 1 in a short amount of time.

[0098] (Note 13) A method for manufacturing a solid battery module, comprising: a step of imaging the solid battery cell described in Note 1 and generating imaging data (S1); a step of identifying the position of the protrusion for contour identification based on the imaging data (S2); a step of determining the stacking position when stacking a plurality of solid battery cells based on the identification result of the identification step (S4); and a step of stacking the plurality of solid battery cells based on the determined stacking position (S5).

[0099] According to the method described above, multiple solid-state battery cells can be stacked so that the positions of the electrode stacks 2 are aligned. As a result, uniform pressure can be applied to each solid-state battery cell 1, preventing degradation of battery performance.

[0100] 1...Solid-state battery cell, 2...Electrode stack, 3...Laminated outer casing, 3-1 to 3-2...Laminated film, 4...Tab, 5...Protrusion, 6...Excess space, 7...Sealing part, 8...Flat part, 9...Side part, 10...Bent part, 11...Pressing member, 20...Inspection device, 21...Imaging unit, 22...Identification unit, 23...Inspection unit, 24...Stacking position control unit, 25...Control device

Claims

1. A solid-state battery cell comprising: an electrode stack having an electrolyte layer containing a solid electrolyte; and a laminate outer casing housing the electrode stack, wherein both sides of the electrode stack in the stacking direction are defined as main surfaces, and the laminate outer casing has contour-identifying protrusions provided at positions corresponding to the outer peripheral edges of the main surfaces of the electrode stack.

2. A method for manufacturing a solid battery cell according to claim 1, wherein the laminate casing includes a pair of laminate films, the manufacturing method comprising: a step of arranging the electrode stack between the pair of laminate films, sealing the pair of laminate films together on the side of the electrode stack to form a sealing portion, and a step of exhausting the space inside the laminate casing after the step of forming the sealing portion, wherein the step of forming the sealing portion includes sealing the pair of laminate films together such that an excess space is formed on the side of the electrode stack, and the excess space is a space of such size that the contour identification protrusion is formed after the exhaust step.

3. A method for manufacturing a solid-state battery cell according to claim 2, wherein the distance of the laminate film from the outer peripheral edge of the main surface of the electrode stack to the sealing portion is defined as a first distance, and the step of forming the sealing portion includes forming the sealing portion such that the first distance is within the range represented by the following formula 1. (Formula 1) Thickness of electrode stack / 2 + (Thickness of laminate film × 2) < First distance < Thickness of electrode stack / 2 + (Thickness of laminate film × 3) 4. A method for manufacturing a solid battery cell according to claim 2, wherein in the step of forming the sealing portion, the laminate film has a flat portion disposed on the main surface of the electrode stack and a side portion provided outside the flat portion and covering the side surface of the electrode stack, and the laminate film is folded between the flat portion and the side portion such that the side portion bulges outward between the flat portion and the sealing portion.

5. A method for manufacturing a solid battery cell according to claim 4, wherein in the step of forming the sealing portion, the outer peripheral edge of the flat portion is located outside the outer peripheral edge of the main surface of the electrode stack.

6. A method for manufacturing a solid battery cell according to claim 2, wherein the exhaust step includes: pressing the laminate film against the main surface of the electrode stack; and exhausting the space inside the laminate casing while the laminate film is pressed against the main surface of the electrode stack.

7. An inspection method comprising: a step of imaging a solid battery cell as described in claim 1 and acquiring imaging data; a step of identifying the protrusions for contour identification based on the imaging data; and a step of determining whether the solid battery cell is good or bad based on the identification result of the identification step.

8. A method for inspecting a solid battery cell according to claim 7, wherein the step of determining whether the solid battery cell is good or bad includes a step of determining whether the solid battery cell is good or bad based on the clarity of the protrusions for contour identification.

9. A method for inspecting a solid battery cell according to claim 7, wherein the step of determining whether the solid battery cell is good or bad includes a step of determining whether the solid battery cell is good or bad based on the length of the identified contour identification protrusion.

10. A method for inspecting a solid battery cell according to claim 7, wherein the step of determining whether the solid battery cell is good or bad includes a step of determining whether the solid battery cell is good or bad based on the linearity of the identified contour identification protrusions.

11. An inspection program for implementing the inspection method described in claim 7 using a computer.

12. An inspection device comprising: an imaging unit that images a solid battery cell as described in claim 1 and generates imaging data; an identification unit that identifies the position of the contour identification protrusions based on the imaging data; and an inspection unit that determines whether the solid battery cell is good or bad based on the identification result of the identification unit.

13. A method for manufacturing a solid battery module, comprising: a step of imaging a solid battery cell according to claim 1 and generating imaging data; a step of identifying the position of the contour identification protrusion based on the imaging data; a step of determining the stacking position when stacking a plurality of solid battery cells based on the identification result of the identification step; and a step of stacking the plurality of solid battery cells based on the determined stacking position.

Images