Power storage cell

Abstract

To provide a power storage cell capable of suppressing liquid depletion and suppressing a decrease in output after high-rate charge and discharge.SOLUTION: In a power storage cell using an electrolytic solution, the power storage cell includes: a first electrode mixture layer 32; a separator 50; and a second electrode mixture layer 42 opposed to the first electrode mixture layer 32 with the separator 50 interposed therebetween. A coating area of at least one of the first electrode mixture layer 32 and the second electrode mixture layer 42 is 600 cm2 or more, and the first electrode mixture layer 32 includes: a first general part 33; and a first wall part 34 surrounding the first general part 33. The first wall part 34 is provided so as to protrude toward the second electrode mixture layer 42 side from the first general part 33, and the second electrode mixture layer 42 includes a second general part 43, and a thin part 45 formed to be thinner than the second general part 43.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] In recent years, as a technology for suppressing output reduction due to electrolyte depletion (liquid starvation) and reduction in high-speed charge / discharge performance, JP 2019-71226 A (Patent Document 1) discloses a storage cell that uses uncrystallized polyvinylidene fluoride (PVdF) in the electrode active material layer (electrode mixture layer). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-71226 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the capacity of batteries has increased, and the area of ​​the electrode mixture layer has also increased accordingly. When a large-area battery (storage cell) that uses an electrolyte is charged and discharged at a high rate, the expansion and contraction of the active material in the electrode mixture layer exerts a large extrusion force on the electrolyte. When the electrolyte is discharged to the outside of the electrode mixture layer, the distance from the discharged liquid to the center of the electrode mixture layer is long, making it difficult for the electrolyte to return to the center. This can easily cause the liquid to dry up, resulting in a decrease in output.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a storage cell that can suppress liquid depletion and suppress output reduction after high-rate charging and discharging. [Means for solving the problem]

[0006] The present disclosure provides a storage cell using an electrolytic solution. The storage cell includes a first electrode mixture layer, a separator, and a second electrode mixture layer facing the first electrode mixture layer with the separator interposed therebetween. The coating area of ​​at least one of the first electrode mixture layer and the second electrode mixture layer is 600 cm2 or less. 2 That's all. The first electrode mixture layer includes a first general portion and a first wall portion surrounding the periphery of the first general portion. The first wall portion is provided so as to protrude toward the second electrode mixture layer beyond the first general portion. The second electrode mixture layer includes a second general portion and a thin portion formed thinner than the second general portion.

[0007] In the energy storage cell according to the present disclosure, the second electrode mixture layer may include a second wall portion that partially surrounds the periphery of the second general portion and protrudes toward the first electrode mixture layer beyond the second general portion, and the thin portion may be formed in a region of the periphery of the second electrode mixture layer where the second wall portion is not provided.

[0008] In the energy storage cell according to the present disclosure, the density of the second wall portion may be higher than the density of the second general portion.

[0009] In the energy storage cell according to the present disclosure, the first electrode mixture layer may be a negative electrode mixture layer, the second electrode mixture layer may be a positive electrode mixture layer, and the second electrode mixture layer may be disposed so as to extend into a space surrounded by the first wall portion.

[0010] In the energy storage cell according to the present disclosure, the density of the first wall portion may be higher than the density of the first general portion. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide an energy storage cell that can suppress liquid depletion and suppress a decrease in output after high-rate charging and discharging. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a schematic plan view of a storage cell according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. [Figure 3] 3 is a schematic plan view of a first electrode mixture layer of the energy storage cell according to the embodiment. FIG. [Figure 4] 3 is a schematic plan view of a second electrode mixture layer of the energy storage cell according to the embodiment. FIG. [Figure 5] FIG. 3 is a schematic view showing a first step of producing a second electrode mixture layer according to the embodiment. [Figure 6] FIG. 4 is a schematic view showing a second step of producing a second electrode mixture layer according to the embodiment. [Figure 7] FIG. 10 is a schematic view showing a third step of producing a second electrode mixture layer according to the embodiment. [Figure 8] FIG. 10 is a diagram showing conditions of a verification experiment. [Figure 9] FIG. 10 is a diagram showing the results of a verification experiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0014] Fig. 1 is a schematic plan view of a storage cell according to an embodiment. Fig. 2 is a cross-sectional view taken along line II-II shown in Fig. 1. Fig. 3 is a schematic plan view of a first electrode mixture layer of the storage cell according to the embodiment. Fig. 4 is a schematic plan view of a second electrode mixture layer of the storage cell according to the embodiment. A storage cell 1 according to an embodiment will be described with reference to Figs. 1 to 4.

[0015] The energy storage cell 1 is used to drive a vehicle, and is installed in, for example, a hybrid vehicle powered by an internal combustion engine such as a gasoline engine or a diesel engine and a motor powered by a rechargeable battery, a plug-in hybrid vehicle that can be externally charged, an electric vehicle, etc.

[0016] In this embodiment, the storage cell 1 is described as a laminated liquid battery, but the storage cell is not limited to a laminated type and may be a rectangular tubular liquid battery. In other words, the exterior body 20, which will be described later, may be made of a rectangular tubular metal member.

[0017] 1 and 2, the energy storage cell 1 includes an electrode assembly 10, an outer casing 20, a first electrode terminal 25N, and a second electrode terminal 25P. For example, the first electrode terminal 25N is a negative electrode terminal, and the second electrode terminal 25P is a positive electrode terminal.

[0018] The exterior body 20 accommodates the electrode assembly 10 and an electrolyte solution. The exterior body 20 is formed, for example, by a laminate. The electrolyte solution is non-aqueous. The electrolyte solution contains, for example, a non-aqueous solvent and a supporting salt such as a lithium salt that generates charge carriers. Note that instead of the electrolyte solution, a polymer (gel) electrolyte or a solid electrolyte may be used.

[0019] The electrode assembly 10 is a so-called laminated electrode assembly, and includes a plurality of first electrodes 30, a plurality of second electrodes 40, and a plurality of separators 50. For example, the first electrode 30 is a negative electrode, and the second electrode 40 is a positive electrode. The electrode assembly 10 is configured by laminating the first electrodes 30 and the second electrodes 40 with the separator 50 interposed therebetween. Note that there may be one or more first electrodes 30 and one or more second electrodes 40.

[0020] Each first electrode 30 includes a first electrode current collector 31 and a first electrode mixture layer 32. The first electrode current collector 31 is provided in a sheet shape. The first electrode current collector 31 is a negative electrode current collector. The first electrode current collector 31 has a rectangular main body and the above-mentioned first electrode tab 36 protruding from one side of the main body.

[0021] The first electrode tabs 36 are arranged to overlap each other when viewed from the stacking direction of the first electrodes 30 and the second electrodes 40. Each of the first electrode tabs 36 is connected to a first electrode terminal 25N.

[0022] The first electrode current collector 31 is formed of, for example, copper foil. A first electrode mixture layer 32 is provided on the surface of the first electrode current collector 31. More specifically, a first electrode mixture layer 32 is provided on each of both surfaces of the first electrode current collector 31 in the stacking direction. Note that the first electrode tab 35 described above does not have a first electrode mixture layer 32. The first electrode mixture layer 32 is a negative electrode mixture layer.

[0023] 2 and 3, the first electrode mixture layer 32 includes a first general portion 33 and a first wall portion 34 that surrounds the periphery of the first general portion 33. The first wall portion 34 is thicker than the first general portion 33. The first wall portion 34 is provided so as to protrude toward the second electrode mixture layer 42 (described below) that faces the first general portion 33 with the separator 50 interposed therebetween.

[0024] The density of the first wall portion 34 may be higher than the density of the first general portion 33. For example, the density of the first wall portion 34 is higher than that of the first general portion 33 by 10% or more.

[0025] The first electrode mixture layer 32 has a substantially rectangular shape when viewed in the stacking direction. The ratio of the length of the long side to the short side of the first electrode mixture layer 32 can be, for example, 65:35, but is not limited to such a ratio.

[0026] The coating area of ​​the first electrode mixture layer 32 is larger than the coating area of ​​the second electrode mixture layer 42. The coating area of ​​the first electrode mixture layer 32 is, for example, 600 cm 2 More specifically, the coating area of ​​the first electrode mixture layer 32 is, for example, 600 cm 2 More than 9000cm 2 The coating area of ​​the first electrode mixture layer 32 is slightly larger than the coating area of ​​the second electrode mixture layer 42 described below. When viewed from the stacking direction, the outer edge of the first electrode mixture layer 32 is located outside the outer edge of the second electrode mixture layer 42. The basis weight of the first electrode mixture layer 32 is, for example, 20 mg / cm 2 That's all.

[0027] The first electrode mixture layer 32 includes a first electrode active material. The first electrode active material is, for example, a material capable of absorbing and releasing lithium ions. For example, a carbon material such as graphite can be used as the first electrode active material.

[0028] 1 and 2, each second electrode 40 includes a second electrode current collector 41 and a second electrode mixture layer 42. The second electrode current collector 41 is provided in a sheet shape. The second electrode current collector 41 is a positive electrode current collector. The second electrode current collector 41 has a rectangular main body and the above-mentioned second electrode tab 46 protruding from one side of the main body.

[0029] The second electrode tabs 46 are arranged to overlap each other when viewed from the stacking direction of the first electrodes 30 and the second electrodes 40. The second electrode tabs 46 are connected to second electrode terminals 25P.

[0030] The second electrode current collector 41 is formed of, for example, aluminum foil or aluminum alloy foil. A second electrode mixture layer 42 is provided on the surface of the second electrode current collector 41. More specifically, a second electrode mixture layer 42 is provided on each of both surfaces of the second electrode current collector 41 in the stacking direction. Note that the second electrode mixture layer 42 is not provided on the second electrode tab 46. The second electrode mixture layer 42 faces the first electrode mixture layer 32 with the separator 50 sandwiched therebetween.

[0031] 2 and 4, the second electrode mixture layer 42 includes a second general portion 43, a second wall portion 44, and a thin-walled portion 45. The second wall portion 44 partially surrounds the periphery of the second general portion 43. The thickness of the second wall portion 44 is greater than the thickness of the second general portion 43. The second wall portion 44 is provided so as to protrude toward the first electrode mixture layer 32, which faces the second wall portion 44 across the separator 50.

[0032] The density of the second wall portion 44 may be higher than the density of the second general portion 43. For example, the density of the second wall portion 44 is higher than that of the second general portion 43 by 10% or more.

[0033] The thin-walled portion 45 is formed thinner than the second general portion 43. The thin-walled portion 45 is formed in a region not surrounded by the second wall portion 44. More specifically, the thin-walled portion 45 is formed in a region of the periphery of the second electrode mixture layer 42 where the second wall portion 44 is not provided. The second general portion 43 is surrounded by the thin-walled portion 45 and the second wall portion 44. In the stacking direction, a gap S is provided between the thin-walled portion 45 and the first electrode mixture layer 32, and excess electrolyte can be discharged into the gap S. The second electrode mixture layer 42 is arranged to enter the space surrounded by the first wall portion 34.

[0034] The second electrode mixture layer 42 has a substantially rectangular shape when viewed in the stacking direction. The ratio of the long side to the short side of the second electrode mixture layer 42 can be, for example, 65:35, but is not limited to such a ratio.

[0035] The coating area of ​​the second electrode mixture layer 42 is, for example, 600 cm 2 More specifically, the coating area of ​​the second electrode mixture layer 42 is, for example, 600 cm 2 More than 9000cm 2 The basis weight of the second electrode mixture layer 42 may be, for example, 30 mg / cm 2 That's all.

[0036] The second electrode mixture layer 42 includes a second electrode active material. The second electrode active material is, for example, a material capable of absorbing and releasing lithium. Examples of the second electrode active material that can be used include lithium cobalt oxide (LiCoO), lithium manganese oxide (LiMnO), and lithium nickel oxide (LiNiO). Alternatively, a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide may be used as the second electrode active material.

[0037] 2 again, separator 50 is interposed between first electrode 30 and second electrode 40. Separator 50 insulates first electrode mixture layer 32 from second electrode mixture layer 42. Separator 50 may be a resin sheet such as polyethylene (PE) or polypropylene (PP).

[0038] 1 again, first electrode terminal 25N has one end and the other end in a direction perpendicular to the stacking direction. One end of first electrode terminal 25N is exposed from exterior body 20. The other end of first electrode terminal 25N is located inside exterior body 20.

[0039] The other end of the first electrode terminal 25N is joined to the first electrode tab 36. This joining may be performed by resistance welding, laser welding, ultrasonic welding, or the like. The first electrode terminal 25N is made of a plate-shaped metal member. Specifically, the first electrode terminal 25N is made of a copper plate.

[0040] The second electrode terminal 25P has one end and the other end in a direction perpendicular to the stacking direction. One end of the second electrode terminal 25P is exposed from the exterior body 20. The other end of the second electrode terminal 25P is located inside the exterior body 20.

[0041] The other end of the second electrode terminal 25P is joined to the second electrode tab 46 by welding or the like. The joining may be performed by resistance welding, laser welding, ultrasonic welding, or the like. The second electrode terminal 25P is made of a plate-shaped metal member. Specifically, the second electrode terminal 25P is made of an aluminum plate.

[0042] 5 to 7 are schematic diagrams showing first to third steps of manufacturing a second electrode mixture layer according to an embodiment. A method of manufacturing second electrode mixture layer 42 will be described with reference to Fig. 5 to Fig. 7. Note that second electrode current collector 41 is omitted from Fig. 5 to Fig. 7 for convenience.

[0043] When manufacturing the second electrode mixture layer 42, as shown in FIG. 5, first, a frame member 70 is placed on the surface of the second electrode current collector 41, and the second electrode slurry 48 is applied to the inside of the frame member using a coating device. The applied second electrode slurry 48 is spread with a squeegee 71. The portion of the squeegee 71 that comes into contact with the second electrode slurry 48 is flat. By setting the viscosity of the second electrode slurry 48 to a predetermined value, the outer edge portion of the second electrode slurry 48 that comes into contact with the frame member 70 becomes a thicker film than the central portion due to surface tension.

[0044] Next, the second electrode slurry 48 with the adjusted surface shape is pressed. For example, the second electrode current collector 41 and the second electrode slurry 48 are sandwiched together using a pressure device such as a pressure roller. As a result, a second electrode mixture layer 42 is formed, as shown in FIG. 6. More specifically, the thick film portion provided on the outer edge of the second electrode slurry 48 becomes a frame-shaped second wall portion 44, and the other portion of the second electrode slurry 48 becomes a second general portion 43. The thickness of the frame-shaped second wall portion 44 is thicker than that of the second general portion 43.

[0045] Subsequently, a part of the frame-shaped second wall portion 44 is removed to form a thin-walled portion 45 as shown in Fig. 7. In this manner, the second electrode mixture layer 42 is formed.

[0046] The first electrode mixture layer 32 is basically manufactured in accordance with the above manufacturing method, but the step of forming the thin-walled portion 45 is omitted.

[0047] As described above, in the energy storage cell 1 according to this embodiment, the first wall portion 34 surrounding the first general portion 33 protrudes toward the second electrode mixture layer 42, and the second electrode mixture layer 42 is configured to include the second general portion 43 and the thin portion 45. As a result, the coating area of ​​at least one of the first electrode mixture layer 32 and the second electrode mixture layer 42 is 600 cm 2Even in cases where the area is as large as above, excess electrolyte can be pushed out into the gap between the thin-walled portion 45 and the first electrode mixture layer 32 when the electrode mixture layer contracts. Furthermore, by providing a first wall portion that is thicker than the general portion, the pushed-out electrolyte can be stored inside the first wall portion. This allows the electrolyte to be quickly resupplied to the electrode mixture layer when the electrode mixture layer expands. As a result, electrolyte depletion can be suppressed, and output reduction after high-rate charging and discharging can be suppressed.

[0048] Furthermore, the second electrode mixture layer 42 includes a second wall portion 44 that partially surrounds the periphery of the second general portion 43 and protrudes toward the first electrode mixture layer 32 beyond the second general portion 43, and the thin-walled portion 45 is formed in an area where the second wall portion 44 is not provided. This makes it difficult for the electrolyte to be discharged beyond the second wall portion 44, so that the location from which excess electrolyte can be discharged can be limited to the thin-walled portion 45. This prevents the distance between the first electrode mixture layer 32 and the second electrode mixture layer 42 from widening when the electrolyte is discharged, thereby suppressing an increase in electrical resistance. As a result, a decrease in output can be suppressed.

[0049] In addition, by making the density of the second wall portion higher than the density of the second general portion, it becomes even more difficult for the electrolyte to be discharged to the outside from the second wall portion 44 side, and the place where the excess electrolyte can be discharged can be further limited to the thin-walled portion, thereby further suppressing the decrease in output.

[0050] Furthermore, by arranging the second electrode mixture layer 42 so as to penetrate into the space surrounded by the first wall portion 34, the distance between the first general portion of the first electrode mixture layer and the second general portion of the second electrode mixture layer can be reduced, thereby suppressing an increase in electrical resistance and, as a result, suppressing a decrease in output.

[0051] Furthermore, by making the density of the first wall portion 34 higher than the density of the first general portion 33, it becomes even more difficult for the electrolyte to be discharged from the first wall portion 34 side to the outside, making it easier to store the electrolyte inside the first wall portion 34.

[0052] (Verification experiment) Fig. 8 is a diagram showing the conditions of the verification experiment. Fig. 9 is a diagram showing the results of the verification experiment. The verification experiment will be described with reference to Figs. 8 and 9.

[0053] In the verification experiment, energy storage cells according to Comparative Example 1 and Examples 1 to 5 were prepared, and the performance of each energy storage cell was evaluated, as shown in Fig. 8. Specifically, 100 cycles of SOC from 0% to 100% were performed at a current value of 2C at an ambient temperature of 25°C, and the output value calculated from the voltage drop when the cell was set to SOC 50% and discharged at 4C for 10 seconds was evaluated.

[0054] The capacity of each storage cell was 6000 mAh. In Comparative Example 1 and each Example, the coating area of ​​the second electrode mixture layer (positive electrode mixture layer) was 600 cm 2 , 3000cm 2 Two types of storage cells were prepared. The coating area of ​​the first electrode mixture layer (negative electrode mixture layer) was approximately the same as that of the second electrode mixture layer. The coating weight of the first electrode (negative electrode) was 20 mg / cm. 2 The second electrode (positive electrode) weight is 30 mg / cm 2 It was decided.

[0055] The prepared energy storage cells according to Comparative Example 1 and Examples 1 to 5 differ in the proportion of the second wall portion 44 of the second electrode mixture layer 42 surrounding the periphery of the second general portion 43.

[0056] 8 and 9, in Comparative Example 1, the second electrode mixture layer was formed only from the second general portion 43 without the second wall portion 44. That is, the proportion of the second wall portion 44 covering the periphery of the second general portion 43 was set to 0%. Similarly, the first electrode mixture layer was formed only from the second general portion 43 without the first wall portion 44.

[0057] In Comparative Example 1, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.36W / cm 2The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.40W / cm 2 This is what happened.

[0058] In Example 1, the proportion of the second wall portion 44 covering the periphery of the second general portion 43 in the second electrode mixture layer was 32.5%. In the second electrode mixture layer, 65% of the periphery of the second general portion 43 was the thin-walled portion 45. The first electrode mixture layer 32 was prepared in which the first wall portion 34 surrounded the entire periphery of the first general portion 33. The density of the first wall portion 34 was higher than the density of the first general portion 33, and the density of the second wall portion 44 was higher than the density of the second general portion 43.

[0059] In Example 1, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.43W / cm 2 The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.50W / cm 2 This is what happened.

[0060] In Example 2, the second electrode mixture layer had the second wall portions 44 covering 50% of the periphery of the second general portion 43. In the second electrode mixture layer, 50% of the periphery of the second general portion 43 was made into the thin-walled portion 45. The first electrode mixture layer 32 was prepared in which the first wall portions 34 surrounded the entire periphery of the first general portion 33. The density of the first wall portions 34 was made higher than the density of the first general portion 33, and the density of the second wall portions 44 was made higher than the density of the second general portion 43.

[0061] In Example 2, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.94W / cm 2 The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.96W / cm 2 This is what happened.

[0062] In Example 3, the proportion of the second wall portion 44 covering the periphery of the second general portion 43 in the second electrode mixture layer was 67.5%. In the second electrode mixture layer, 50% of the periphery of the second general portion 43 was the thin-walled portion 45. The first electrode mixture layer 32 was prepared in which the first wall portion 34 surrounded the entire periphery of the first general portion 33. The density of the first wall portion 34 was higher than the density of the first general portion 33, and the density of the second wall portion 44 was higher than the density of the second general portion 43.

[0063] In Example 3, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.97W / cm 2 The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.98W / cm 2 This is what happened.

[0064] In Example 4, the second electrode mixture layer had the second wall portions 44 covering 90% of the periphery of the second general portion 43. In the second electrode mixture layer, 90% of the periphery of the second general portion 43 was the thin-walled portion 45. The first electrode mixture layer 32 was prepared in which the first wall portions 34 surrounded the entire periphery of the first general portion 33. The density of the first wall portions 34 was higher than the density of the first general portion 33, and the density of the second wall portions 44 was higher than the density of the second general portion 43.

[0065] In Example 4, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.97W / cm 2 The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.98W / cm 2 This is what happened.

[0066] In Example 5, the second electrode mixture layer had the second wall portions 44 covering 95% of the periphery of the second general portion 43. In the second electrode mixture layer, 90% of the periphery of the second general portion 43 was the thin-walled portion 45. The first electrode mixture layer 32 was prepared in which the first wall portions 34 surrounded the entire periphery of the first general portion 33. The density of the first wall portions 34 was higher than the density of the first general portion 33, and the density of the second wall portions 44 was higher than the density of the second general portion 43.

[0067] In Example 5, the coating area of ​​the second electrode mixture layer 42 was 600 cm 2 In this case, the output according to the above evaluation is approximately 0.97W / cm 2 The coating area of ​​the second electrode mixture layer 42 was set to 3000 cm 2 In this case, it is approximately 0.98W / cm 2 This is what happened.

[0068] In all of Examples 1 to 5, the coating area of ​​the second electrode mixture layer 42 was increased to 600 cm 2 compared to Comparative Example 1. 2 In this case, the coating area of ​​the second electrode mixture layer 42 is set to 3000 cm 2 In other words, it was confirmed that the output power increased in both cases where the first wall portion 34 protruded toward the second electrode mixture layer 42 side more than the first general portion 33 and the second electrode mixture layer included a thin portion, thereby suppressing the decrease in output power after high-rate charging and discharging.

[0069] Furthermore, from the above results, it was confirmed that the formation of the thin-walled portion 45 makes it possible to form a space between the thin-walled portion 45 and the first electrode mixture layer 32 in the stacking direction, allowing excess electrolyte to be discharged into the space and for the discharged electrolyte to be stored inside the first wall portion 34 of the first electrode mixture layer 32. In this way, it was confirmed that the electrolyte can be held in the vicinity of the electrode, making it possible to quickly discharge and supply the electrolyte in response to the expansion and contraction of the electrode mixture layer.

[0070] The coating area of ​​the second electrode mixture layer 42 is set to 600 cm 2 It was confirmed that by doing so, it is possible to suppress the decrease in output after high-rate charging and discharging.

[0071] Furthermore, Examples 2 to 5 have increased output compared to Example 1, and it was confirmed that by setting the proportion of the second wall portion 44 covering the periphery of the second general portion 43 to be 50% or more and 95% or less, the decrease in output after high-rate charging and discharging can be further suppressed.

[0072] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0073] 1 storage cell, 10 electrode body, 20 outer casing, 25N first electrode terminal, 25P second electrode terminal, 30 first electrode, 31 first electrode current collector, 32 first electrode mixture layer, 33 first general portion, 34 first wall portion, 36 first electrode tab, 40 second electrode, 41 second electrode current collector, 42 second electrode mixture layer, 43 second general portion, 44 second wall portion, 45 thin portion, 46 second electrode tab, 48 second electrode slurry, 50 separator, 70 frame member, 71 squeegee, S gap.

Claims

1. A storage cell using an electrolytic solution, a first electrode mixture layer; A separator; a second electrode mixture layer facing the first electrode mixture layer with the separator interposed therebetween, The coating area of ​​at least one of the first electrode mixture layer and the second electrode mixture layer is 600 cm ２ That's all, the first electrode mixture layer includes a first general portion and a first wall portion surrounding the first general portion, the first wall portion is provided so as to protrude toward the second electrode mixture layer side beyond the first general portion, The second electrode mixture layer includes a second general portion and a thin portion formed thinner than the second general portion.

2. the second electrode mixture layer includes a second wall portion that partially surrounds the periphery of the second general portion and protrudes toward the first electrode mixture layer beyond the second general portion, The energy storage cell according to claim 1 , wherein the thin-walled portion is formed in a region of the periphery of the second electrode mixture layer where the second wall portion is not provided.

3. The energy storage cell according to claim 2 , wherein the density of the second wall portion is higher than the density of the second general portion.

4. the first electrode mixture layer is a negative electrode mixture layer, the second electrode mixture layer is a positive electrode mixture layer, The energy storage cell according to claim 1 , wherein the second electrode mixture layer is disposed so as to extend into a space surrounded by the first wall portion.

5. The energy storage cell according to claim 1 , wherein the density of the first wall portion is higher than the density of the first general portion.

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