Power storage module

Abstract

To provide a power storage module capable of suppressing an adverse effect caused by an expansion of a gas generated by a vaporization of a high-temperature electrolytic solution.SOLUTION: A power storage module 1 includes: a first active material layer 120; a second active material layer 130; a separator 400 disposed between the first active material layer 120 and the second active material layer 130; and a gas discharge regulating part 131. The second active material layer 130 includes a main surface 130b located on the first active material layer 120 side. The main surface 130b includes a facing region 130c facing the first active material layer 120. The gas discharge restricting part 131 is provided on the main surface 130b, on the outer side of an opposing region 130c, and at a position adjacent to the opposing region 130c.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] For example, Japanese Patent Application Laid-Open No. 2020-177761 (Patent Document 1) discloses an energy storage module comprising an electrode stack formed from multiple unit batteries and a resin material arranged to surround the side surfaces of the electrode stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-177761 Summary of the Invention [Problem to be solved by the invention]

[0004] The energy storage module includes a resin frame and an electrode stack disposed within the resin frame. The electrode stack includes a plurality of unit cells.

[0005] Each of the multiple unit batteries includes a first current collector, a first active material layer, a separator, a second active material layer, and a second current collector. The separator is disposed between the first active material layer and the second active material layer. In unit batteries adjacent to each other in the stacking direction, the first current collector of one unit battery is in contact with the second current collector of the other unit battery, and the contacting first and second current collectors form a stacked current collector.

[0006] The energy storage module is sealed by a resin frame, a first current collector plate, and a second current collector plate. An electrolyte solution is sealed inside the energy storage module. The first active material layer, the second active material layer, and the separator are impregnated with the electrolyte solution.

[0007] In an energy storage module configured as described above, if the separator loses its insulating function, the first and second active material layers, which face each other across the separator, short-circuit, generating a short-circuit current. The short-circuit current generates Joule heat, which heats the electrolyte. The heated electrolyte gasifies. The gas increases the internal pressure of the energy storage module, causing it to expand. The energy storage module is then unable to contain the gas inside, and the gas may burst the resin frame of the module and escape to the outside.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide an energy storage module that can suppress the adverse effects caused by the expansion of gas generated by the evaporation of heated electrolyte. [Means for solving the problem]

[0009] An energy storage module according to a first aspect of the present disclosure includes a first active material layer, a second active material layer, a separator disposed between the first active material layer and the second active material layer, and a protrusion. The second active material layer includes a main surface facing the first active material layer. The main surface includes an opposing region opposing the first active material layer. The protrusion is provided on the main surface, and is located outside the opposing region and adjacent to the opposing region.

[0010] The protruding portion of the electricity storage module according to the first aspect of the present disclosure is provided so as to extend in an annular shape along the outer circumferential edge of the facing region.

[0011] The protrusions of the energy storage module according to the first aspect of the present disclosure have a height of 50 μm or more from the main surface.

[0012] The energy storage module according to a first aspect of the present disclosure further includes a current collector plate provided with a first active material layer. The current collector plate is located on the opposite side of the first active material layer from the separator. At least one groove is provided in the first active material layer. The current collector plate is exposed from the first active material layer in the at least one groove.

[0013] The first active material layer and the second active material layer of the electricity storage module according to the first aspect of the present disclosure each have a length of at least 1 m in either the length direction or the width direction.

[0014] The width of at least one groove in the energy storage module according to the first aspect of the present disclosure is not less than 0.5 mm and not more than 20 mm.

[0015] The interval between at least one groove portion of the energy storage module according to the first aspect of the present disclosure is not less than 40 mm and not more than 350 mm.

[0016] An energy storage module according to a second aspect of the present disclosure includes a plurality of bipolar electrodes stacked in a stacking direction and a separator disposed between the plurality of bipolar electrodes. Each of the plurality of bipolar electrodes includes a current collector plate, a first active material layer, a second active material layer, and a protrusion. The current collector plate has a first coated surface and a second coated surface in the stacking direction. The first active material layer is applied to the first coated surface of the current collector plate. The second active material layer is applied to the second coated surface of the current collector plate and has a main surface. The main surface is covered by a separator. The main surface has an opposing region that faces the first active material layer of an adjacent bipolar electrode across the separator. The protrusion is provided on the main surface and is located outside the opposing region and adjacent to the opposing region.

[0017] The protruding portion of the electricity storage module according to the second aspect of the present disclosure is provided so as to extend in an annular shape along the outer circumferential edge of the facing region.

[0018] In the electricity storage module according to the second aspect of the present disclosure, at least one groove is provided in the first active material layer, and the current collector plate is exposed from the first active material layer in the at least one groove. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide an electricity storage module that can suppress adverse effects caused by expansion of gas generated by evaporation of an electrolyte solution at a high temperature. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram schematically illustrating an energy storage module according to an embodiment of the present disclosure. [Figure 2] 2 is an end view of the energy storage module shown in FIG. 1, viewed in the direction of the arrows along line II-II. [Figure 3] FIG. 3 is a diagram schematically showing the first active material layer shown in FIG. 2. [Figure 4] FIG. 1 is a diagram showing comparative test conditions and evaluation results for each condition. [Figure 5] FIG. 10 is a diagram showing classification of the degree of temperature increase. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0022] <Configuration of energy storage module> Fig. 1 is a schematic diagram of an energy storage module according to an embodiment of the present disclosure. In Fig. 1 and other figures, a stacking direction H indicates the stacking direction of the energy storage module 1. In Fig. 1, a width direction W and a length direction L indicate the width direction and length direction of the energy storage module 1, respectively.

[0023] 1, the energy storage module 1 is formed in a rectangular parallelepiped shape. The energy storage module 1 has a first main surface 1a and a second main surface 1b arranged at an interval in a stacking direction H. The energy storage module 1 includes an electrode stack 10 and a resin part 500.

[0024] Fig. 2 is an end view of the energy storage module shown in Fig. 1, viewed in the direction of the arrows along line II-II. The electrode stack 10 includes a plurality of unit batteries 100. The plurality of unit batteries 100 are stacked in a stacking direction H.

[0025] Each unit battery 100 includes a first current collector plate 112 , a first active material layer 120 , a separator 400 , a second active material layer 130 , and a second current collector plate 113 .

[0026] The first active material layer 120 is, for example, a positive electrode active material layer. The first active material layer 120 is formed on the first application surface 112a of the first current collector 112. The first application surface 112a is the lower surface of the first current collector 112.

[0027] The second active material layer 130 is, for example, a negative electrode active material layer. The second active material layer 130 is formed on the second application surface 113a of the second current collector plate 113. The second application surface 113a is the upper surface of the second current collector plate 113.

[0028] The separator 400 is disposed between the first active material layer 120 and the second active material layer 130 .

[0029] In unit batteries 100 adjacent to each other in the stacking direction H, the first current collector plate 112 of one unit battery 100 is in contact with the second current collector plate 113 of the other unit battery 100. The contacting first current collector plate 112 and second current collector plate 113 form a stacked current collector plate 110.

[0030] Although an example has been shown in which the first current collector plate 112 and the second current collector plate 113 are in contact with each other, the present disclosure is not limited to this. The first current collector plate 112 and the second current collector plate 113 need only be electrically connected. For example, the first current collector plate 112 and the second current collector plate 113 may be electrically connected by being laminated with a conductive adhesive, a conductive material, a conductive resin, or a combination thereof interposed therebetween. The first current collector plate and the second current collector plate may also be electrically connected by a conducting wire or a terminal.

[0031] The laminated current collector 110 is formed in a rectangular shape when viewed from above from a position away from the laminated current collector 110 in the stacking direction H. The laminated current collector 110 has a first current collector 112 and a second current collector 113. The first current collector 112 is made of aluminum, for example. The second current collector 113 is made of copper, for example. The laminated current collector 110 has, in the stacking direction H, a first coated surface 112a which is the surface of the first current collector 112, and a second coated surface 113a which is the surface of the second current collector 113.

[0032] 3 is a diagram schematically showing the first active material layer. For example, when the first active material layer 120 is viewed from a position away from the first active material layer 120 in the stacking direction H, the first active material layer 120 is formed in a rectangular shape. The first active material layer 120 is formed so that the length in either the length direction L or the width direction W is at least 1.0 m or more. At least one groove portion 121 is formed in the first active material layer 120.

[0033] The groove portions 121 are formed to extend in the length direction L. Both ends of the groove portions 121 reach the outer peripheral edge portion 120a of the first active material layer 120, and the first active material layer 120 is divided into a plurality of portions by the plurality of groove portions 121. The groove width t of the groove portions 121 is, for example, 0.5 mm or more and, for example, 20.0 mm or less. The groove portions 121 are arranged with a gap g between adjacent groove portions 121 in the width direction W. The gap g is, for example, 40 mm or more and, for example, 350 mm or less.

[0034] Referring again to FIG. 2, in the groove portion 121, the first coating surface 112a of the first current collector plate 112 is exposed from the first active material layer 120.

[0035] For example, when the second active material layer 130 is viewed from a position away from the second active material layer 130 in the stacking direction H, the second active material layer 130 is formed in a rectangular shape and is formed to protrude from the first active material layer 120. Specifically, the outer peripheral edge portion 130a of the second active material layer 130 protrudes outward from the outer peripheral edge portion 120a of the first active material layer 120 by a phase difference d. The phase difference d is, for example, 0.5 mm or more. The second active material layer 130 is formed so that the length in either the length direction L or the width direction W is at least 1.0 m or more.

[0036] In the unit battery 100, the second active material layer 130 has a main surface 130b located on the first active material layer 120 side.

[0037] The main surface 130b has a facing region 130c that faces the first active material layer 120. When the second active material layer 130 and the first active material layer 120 are viewed from a position away from the stacking direction H, the outer circumferential edge portion 120a is located inside the outer circumferential edge portion 130a. Therefore, the facing region 130c is part of the main surface 130b.

[0038] The second active material layer 130 includes a gas emission control portion 131. The gas emission control portion 131 is a protrusion formed integrally with the second active material layer 130. The gas emission control portion 131 is provided on the main surface 130b. More specifically, the gas emission control portion 131 is formed outside the facing region 130c, at a position adjacent to the facing region 130c. The gas emission control portion 131 is formed so as to extend in an annular shape along the outer periphery of the facing region 130c. The gas emission control portion 131 is formed so as to protrude by a height h from the main surface 130b. The height h is 50 μm or more. The cross-sectional shape of the gas emission control portion 131 is semicircular, but may also be rectangular, trapezoidal, or elliptical.

[0039] The gas emission restricting portion 131 is an example of a convex portion of the present disclosure. The separator 400 is formed in a rectangular shape when viewed from a position spaced apart from the separator 400 in the stacking direction H. The separator 400 is formed so as to protrude from the outer peripheral edge portion 130a.

[0040] The separator 400 is formed, for example, in a sheet shape. The separator 400 may be a porous sheet or a nonwoven fabric. The separator 400 includes, for example, a polymer that absorbs and retains an electrolyte. Examples of materials that form the separator 400 include polypropylene (PP), polyethylene (PE), polyolefin, and polyester.

[0041] Separator 400 may have a single-layer structure or a multi-layer structure. For example, in order to improve heat resistance and insulation properties, separator 400 may have a multi-layer structure formed of a porous resin layer and a ceramic layer.

[0042] The resin part 500 is formed in an annular shape so as to surround the electrode stack 10. The outer peripheral edge of the laminated current collector plate 110 and the outer peripheral edge of the separator 400 are embedded inside the resin part 500. A sealed space R is formed by the resin part 500 and the laminated current collector plate 110 embedded in the resin part 500. An electrolyte solution is disposed in the sealed space R.

[0043] The first current collector plate 112 and the second current collector plate 113 are exposed at both ends of the energy storage module 1 in the stacking direction H. By arranging a conductive member (such as a current collector plate) in these exposed portions, it becomes possible to electrically connect multiple energy storage modules 1 in series.

[0044] In the above, the configuration of the power storage module 1 has been described with a focus on the unit battery 100. However, the power storage module 1 is a bipolar battery and includes a plurality of bipolar electrodes 101. Details will be described below.

[0045] The energy storage module 1 includes a plurality of bipolar electrodes 101 stacked in a stacking direction H, and separators 400. The separators 400 are disposed between the bipolar electrodes 101.

[0046] The bipolar electrode 101 has a second active material layer 130, a laminated current collector 110, and a first active material layer 120. The laminated current collector 110 has a first current collector 112 and a second current collector 113. The laminated current collector 110 has a first coated surface 112a and a second coated surface 113a. The first coated surface 112a and the second coated surface 113a are arranged with an interval in the stacking direction H. The second active material layer 130 is coated on the second coated surface 113a. The first active material layer 120 is coated on the first coated surface 112a. As a result, the laminated current collector 110 is located on the opposite side of the separator 400 with respect to the first active material layer 120.

[0047] The second active material layer 130 has a main surface 130b. In the bipolar electrode 101, the main surface 130b is the surface of the second active material layer 130 and is covered with the separator 400. The main surface 130b also has a facing region 130c.

[0048] In the bipolar electrode 101, the facing region 130c is a region facing the first active material layer 120 of the bipolar electrode 101 adjacent in the stacking direction H with the separator 400 sandwiched therebetween.

[0049] <Comparative test> Fig. 4 shows the conditions of each energy storage module subject to the comparative test and the evaluation results of the degree of temperature rise for each energy storage module. Fig. 5 shows the classification of the degree of temperature rise. The comparative test will be described with reference to Figs. 4 and 5.

[0050] In the comparative test, energy storage modules shown in Example 1 group and Example 2 group in Fig. 4 were prepared. The evaluation of the degree of temperature rise of each of the energy storage modules shown in Example 1 group and Example 2 group was compared with the evaluation of the degree of temperature rise of an energy storage module according to a comparison standard (not shown in Fig. 4), to confirm whether or not the gas emission control portion 131 and the groove portion 121 have an effect of suppressing temperature rise. Unless otherwise specified, the energy storage module according to the comparison standard, the energy storage module shown in Example 1 group, and the energy storage module shown in Example 2 group have a common configuration and are the same configuration as the energy storage module 1 according to an embodiment of the present disclosure.

[0051] The common configuration of each energy storage module will be described in detail below. Each energy storage module has 30 unit batteries 100, and has an outer shape of 1535 mm in the length direction L and 1210 mm in the width direction W.

[0052] The specific configuration of each power storage module will be described. The first active material layer 120 and the second active material layer 130 of the power storage module serving as a comparison reference do not have grooves 121 and gas emission restriction portions 131 formed therein.

[0053] The first active material layer 120 of the energy storage module according to Example 1 does not have a groove 121. On the other hand, the energy storage module according to Example 1 has nine types of second active material layers 130. Specifically, the second active material layers 130 have a phase difference d of 0.5 mm, 1.0 mm, or 2.0 mm, and a height h of the gas emission restriction portion 131 of 50 μm, 100 μm, or 200 μm.

[0054] The energy storage module according to Example 2 has a second active material layer 130 in which the phase difference d is 2.0 mm and the height h of the gas emission restriction portion 131 is 50 μm. The energy storage module according to Example 2 has ten types of first active material layers 120. Specifically, the first type is a first active material layer 120 in which two grooves 121 are formed, each having a groove width t of 0.5 mm, 0.8 mm, 1.2 mm, 2.5 mm, or 10.0 mm. The second type is a first active material layer 120 in which four, six, or eight grooves 121 are formed, each having a groove width t of 0.5 mm. The third type is a first active material layer 120 in which ten grooves 121 are formed, each having a groove width t of 2.5 mm or 20.0 mm.

[0055] A comparative test was conducted to evaluate the degree of temperature rise of each energy storage module according to the comparison standard, each energy storage module according to Example 1, and each energy storage module according to Example 2. The specific method of the comparative test will be described below. First, the first main surface 1a of the energy storage module is heated with a heater, and the heating is stopped when the second main surface 1b reaches 300°C. After heating is completed, the state of the energy storage module until self-heating due to the rise in temperature stops, and the interior of the energy storage module after self-heating stops are observed. Based on the observation results, the degree of temperature rise of each energy storage module is evaluated on a 5-point scale.

[0056] Figure 5 shows the classification of the degree of temperature rise. As shown in Figure 5, the degree of temperature rise is classified into five categories: Classification 1: Overall temperature rise, large amount of gas ejected outside the battery; Classification 2: Overall temperature rise, gas ejected outside the battery; Classification 3: Localized temperature rise and stop, gas ejected outside the battery; Classification 4: Localized temperature rise and stop, small amount of gas ejected outside the battery; Classification 5: Localized temperature rise and stop, no gas ejected outside the battery. Note that overall temperature rise means that all cells in the energy storage module become hot. Localized temperature rise means that only some of the cells in the energy storage module become hot.

[0057] In addition, each classification was rated on a 5-point scale, with classification 1 being the most severe and lowest rating, and classification 5 being the least severe and highest rating. Classification 1 was rated 1, and classification 5 was rated 5.

[0058] After evaluating the degree of temperature rise of each of the energy storage modules, the evaluation of the degree of temperature rise of the energy storage module according to the comparison standard was compared with the evaluation of the degree of temperature rise of each of the energy storage modules according to Example 1 and the evaluation of the degree of temperature rise of each of the energy storage modules according to Example 2. The configuration of the energy storage module that obtained a higher evaluation than the evaluation of the degree of temperature rise of the energy storage module according to the comparison standard was determined to be a configuration that provides a temperature rise suppression effect.

[0059] The results of the comparison test will be explained below. First, the evaluation results of the degree of temperature rise of each power storage module will be explained with reference to FIG.

[0060] The inventors found that when the comparative energy storage module was heated using the above-mentioned heating method, a large amount of gas was ejected outside the energy storage module, causing the temperature to rise over the entire module. Therefore, the comparative energy storage module was given a rating of 1 for the degree of temperature rise.

[0061] The evaluation of the degree of temperature rise for each of the power storage modules according to Example 1 group was all 3. The degree of temperature rise of each of the energy storage modules according to Example 2 group was evaluated as 3 to 5. More specifically, the degree of temperature rise of an energy storage module having a first active material layer 120 in which two grooves 121 with a groove width t of 10.0 mm were formed was evaluated as 4. The degree of temperature rise of an energy storage module having a first active material layer 120 in which eight grooves 121 with a groove width t of 0.5 mm were formed was evaluated as 4. The degree of temperature rise of an energy storage module according to Example 2 group having a first active material layer 120 in which ten grooves 121 with a groove width t of 2.5 mm or 20.0 mm were formed was evaluated as 5. The degree of temperature rise of the other energy storage modules according to Example 2 group was evaluated as 3.

[0062] Next, the results of a comparison of the evaluation of the degree of temperature rise of each power storage module will be described. First, the evaluation of the degree of temperature rise of the power storage module according to the comparison standard was compared with the evaluation of the degree of temperature rise of each of the power storage modules according to Example 1 group.

[0063] As a result, the evaluation of the degree of temperature rise of all the energy storage modules according to Example 1 group was higher than the evaluation of the degree of temperature rise of the energy storage module according to the comparison standard. This confirmed that a temperature rise suppression effect can be obtained by forming the gas emission control part 131 formed to extend in an annular shape so as to be adjacent to the opposing region 130c of the second active material layer 130.

[0064] Secondly, the evaluation of the degree of temperature rise of each of the electricity storage modules in the Example 1 group was compared with each other.

[0065] As a result, the evaluation of the degree of temperature rise was the same for all of the energy storage modules according to Example 1. This confirmed that there was no difference in the effect of suppressing temperature rise obtained by forming gas emission control section 131 in second active material layer 130 within the range of combinations of phase difference d and height h of gas emission control section 131 shown in Example 1 in Fig. 4 .

[0066] Thirdly, the evaluation of the degree of temperature rise of the power storage module according to the comparison standard was compared with the evaluation of the degree of temperature rise of each of the power storage modules according to Example 2 group.

[0067] As a result, the evaluation of the degree of temperature rise of all the energy storage modules according to Example 2 group was higher than the evaluation of the degree of temperature rise of the energy storage module according to the comparison standard. This confirmed that the effect of suppressing temperature rise can be obtained by forming groove portion 121 in first active material layer 120 and gas emission control portion 131 in second active material layer 130.

[0068] Fourth, an evaluation of the degree of temperature rise of each of the energy storage modules according to Example 1 was compared with an evaluation of the degree of temperature rise of each of the energy storage modules according to Example 2. More specifically, a comparison was made between an energy storage module according to Example 1 having a second active material layer 130 formed with a gas emission restriction portion 131 having a phase difference d of 2.0 mm and a height h of 50 μm, and an energy storage module according to Example 2 having a second active material layer 130 formed with a gas emission restriction portion 131 having a phase difference d of 2.0 mm and a height h of 50 μm, and a first active material layer 120 formed with grooves 121 having a groove width t of 0.5 mm.

[0069] As a result, the evaluation of the degree of temperature rise of the storage module having the first active material layer 120 in which no groove portion 121 was formed was the same as the evaluation of the degree of temperature rise of the storage module having the first active material layer 120 in which two, four, or six groove portions 121 with a groove width t of 0.5 mm were formed.

[0070] On the other hand, the evaluation of the degree of temperature rise of the storage module having a first active material layer 120 in which eight groove portions 121 with a groove width t of 0.5 mm were formed was higher than the evaluation of the degree of temperature rise of the storage module having a first active material layer 120 in which six groove portions 121 with a groove width t of 0.5 mm were formed.

[0071] This confirmed that the first active material layer 120 having the predetermined number of grooves 121 formed therein has a higher effect of suppressing high temperatures than the first active material layer 120 having no grooves 121 formed therein. Here, the predetermined number refers to eight or more grooves 121 having a groove width t of 0.5 mm.

[0072] Fifth, the evaluation of the degree of temperature rise of each of the power storage modules according to Example 2 group was compared with each other.

[0073] As a result, the evaluation of the degree of temperature rise of the energy storage module having the first active material layer 120 in which two grooves 121 with a groove width t of 10.0 mm were formed was higher than the evaluation of the degree of temperature rise of the energy storage module having the first active material layer 120 in which two grooves 121 with a groove width t of 2.5 mm were formed. This confirmed that a greater effect of suppressing temperature rise can be obtained by widening the groove width t.

[0074] On the other hand, the evaluation of the degree of temperature rise of the energy storage module in which ten grooves 121 with a groove width t of 20.0 mm were formed was the same as the evaluation of the degree of temperature rise of the energy storage module in which ten grooves 121 with a groove width t of 2.5 mm were formed. This confirmed that the effect of suppressing temperature rise by widening the groove width t is limited.

[0075] Sixth, the evaluation of the degree of temperature rise of the storage module according to the comparison standard, the evaluation of the degree of temperature rise of each storage module according to Example 1 group, and the evaluation of the degree of temperature rise of each storage module according to Example 2 group were compared.

[0076] As a result, the energy storage module according to Example 2, in which ten grooves 121 with a groove width t of 2.5 mm or 20.0 mm were formed in the first active material layer 120, was evaluated as having the highest degree of temperature rise. This confirmed that, within the range of test conditions of this comparative test, an energy storage module having a second active material layer 130 in which a gas emission restriction portion 131 with a phase difference d of 2.0 mm and a height h of 50 μm was formed, and a first active material layer 120 in which ten grooves 121 with a groove width t of 2.5 mm or 20.0 mm were formed, had the highest effect of suppressing temperature rise within the test conditions of this comparative test. From the viewpoint of ensuring the application area of ​​the first active material layer 120, it may be determined that the most preferable conditions for the energy storage module are a second active material layer 130 having a gas emission control portion 131 formed thereon with a phase difference d of 2.0 mm and a height h of 50 μm, and a first active material layer 120 having ten groove portions 121 formed thereon, each having a groove width t of 2.5 mm.

[0077] In this test, the high temperature suppression effect was obtained when the gap g was 40 mm or more and 350 mm or less.

[0078] In the embodiment of the present disclosure, the separator 400 is a porous body formed, for example, from a porous sheet. The gas emission control portion 131 is formed adjacent to the facing region 130c. With this configuration, the separator 400 conforms to the shape of the gas emission control portion 131, and a bent portion is formed in the separator 400.

[0079] The first active material layer and the second active material layer short-circuit, generating a short-circuit current. The Joule heat generated by the short-circuit current heats the electrolyte, turning it into a gas, and its volume expands, creating a small space between the first active material layer and the second active material layer. The gas moves horizontally through this space. The convex portion acts as a physical barrier to the gas moving horizontally, preventing it from being discharged outside the gas emission control section.

[0080] This makes it possible to suppress an increase in the internal pressure of the space R and to suppress the breakage of a portion of the resin part 500. If a portion of the resin part 500 were to break, there is a risk that the laminated current collecting plates 110 adjacent to each other in the stacking direction H will come into contact with each other and cause a short circuit.

[0081] On the other hand, in the energy storage module 1 according to the embodiment of the present disclosure, as described above, the resin part 500 can be prevented from breaking, and therefore the occurrence of the above-described adverse effects can be prevented.

[0082] In the embodiment of the present disclosure, grooves 121 are formed in the first active material layer 120. With this configuration, gas generated by evaporation of the electrolyte between the separators 400 rises through the grooves 121 and reaches the laminated current collector plate 110. The gas that reaches the laminated current collector plate 110 dissipates heat to the laminated current collector plate 110, thereby lowering the gas temperature. By lowering the gas temperature in this manner, melting of the separators 400 can be suppressed, and short-circuiting between the first active material layer 120 and the second active material layer 130 can be suppressed. Furthermore, the lowering of the gas temperature reduces the volume of the gas, thereby reducing the pressure in the space R.

[0083] In particular, in bipolar electrode 101 having laminated current collector 110 formed by direct contact between first current collector 112 and second current collector 113, the heat of the gas that passes through groove 121 and reaches the current collector is more easily dissipated through the current collector than in a battery in which first current collector 112 and second current collector 113 are electrically connected via conductors, terminals, etc. As a result, the temperature of the gas drops, the volume of the gas decreases, and the pressure in space R can be further reduced.

[0084] In the above embodiment, the gas emission control portion 131 is formed integrally with the second active material layer 130, but the present disclosure is not limited to this. For example, the gas emission control portion 131 may be formed separately from the second active material layer 130 and disposed outside the facing region 130c included in the main surface 130b and adjacent to the facing region 130c.

[0085] The gas emission control portion 131 may be formed of a material different from that of the second active material layer 130. For example, the gas emission control portion 131 may be formed by forming a resin or the like in a ring shape on the main surface 130b along the outer periphery of the facing region 130c.

[0086] In the above embodiment, the grooves 121 are formed to extend in the length direction L, but the present disclosure is not limited to this. For example, the grooves 121 may be formed in a lattice shape when viewed from the stacking direction H, or may be formed partially. Furthermore, the grooves 121 do not have to be straight.

[0087] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0088] 1 Energy storage module, 1a First main surface, 1b Second main surface, 10 Electrode laminate, 100 Unit battery, 101 Bipolar electrode, 110 Laminated current collector, 112 First current collector, 112a First coated surface, 113 Second current collector, 113a Second coated surface, 120 First active material layer, 120a Outer periphery, 121 Groove, 130 Second active material layer, 130a Outer periphery, 130b Main surface, 130c Facing region, 131 Gas emission control section, 400 Separator, 500 Resin section, d Phase difference, g Spacing, h Height, H Stacking direction, L Length direction, R Space, t Groove width, W Width direction.

Claims

1. a first active material layer and a second active material layer; a separator disposed between the first active material layer and the second active material layer; a protrusion; the second active material layer includes a main surface located on the first active material layer side, the main surface includes a facing region facing the first active material layer, The protrusion is provided on the main surface, and is provided outside the facing region at a position adjacent to the facing region.

2. The energy storage module according to claim 1 , wherein the protrusion is provided so as to extend in an annular shape along an outer periphery of the facing region.

3. The energy storage module according to claim 1 , wherein the protrusions have a height of 50 μm or more from the main surface.

4. further comprising a current collector plate on which the first active material layer is provided, the current collector is located on the opposite side of the first active material layer from the separator, the first active material layer has at least one groove portion; The energy storage module according to claim 1 , wherein the current collector plate is exposed from the first active material layer in the at least one groove.

5. The energy storage module according to claim 4 , wherein the first active material layer and the second active material layer have a length of at least 1 m in either the length direction or the width direction.

6. 6. The energy storage module according to claim 4, wherein the at least one groove has a width of 0.5 mm or more and 20 mm or less.

7. The energy storage module according to claim 4 or 5, wherein the interval between the at least one groove is equal to or greater than 40 mm and equal to or less than 350 mm.

8. a plurality of bipolar electrodes stacked in a stacking direction; a separator disposed between the plurality of bipolar electrodes; each of the plurality of bipolar electrodes includes a current collector plate, a first active material layer, a second active material layer, and a protrusion; the current collector plate has a first coated surface and a second coated surface in the stacking direction, the first active material layer is applied to the first application surface of the current collector plate, the second active material layer is applied to the second application surface of the current collector plate and has a main surface, the main surface is covered by the separator, the main surface has an opposing region opposing the first active material layer of one of the plurality of bipolar electrodes adjacent to each other with the separator interposed therebetween, The protrusion is provided on the main surface, and is provided outside the facing region at a position adjacent to the facing region.

9. The energy storage module according to claim 8 , wherein the protrusion is provided so as to extend in an annular shape along an outer periphery of the facing region.

10. the first active material layer has at least one groove portion; The electricity storage module according to claim 8 or 9 , wherein the current collector plate is exposed from the first active material layer in the at least one groove.

Images