Manufacturing method for energy storage modules

Abstract

To provide a manufacturing method for a battery module with a stack structure comprising energy storage cells and heat insulating material, which suppresses deformation of the energy storage cells. [Solution] A method for manufacturing an energy storage module comprising a plurality of energy storage cells stacked along a first direction and at least one heat insulating member disposed between two adjacent energy storage cells, comprising the steps of pressing a region of the heat insulating member in the thickness direction of the heat insulating member, at least a region of the heat insulating member that includes a non-identical position portion that overlaps in the first direction with a portion of at least one adjacent energy storage cell in which electrodes are not housed, and arranging the heat insulating member so that the portion of the heat insulating member that does not house electrodes and the pressed portion of the heat insulating member overlap in the first direction.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an electricity storage module.

Background Art

[0002] In recent years, with the increase in capacity and output of energy devices, battery modules having a stack structure in which a plurality of electricity storage cells are stacked have been widely used. In the stack structure, a member such as a sheet having heat insulation performance may be used for the purpose of preventing chain heat generation.

[0003] For example, in a battery module in which a plurality of battery cells are stacked with buffer sheets interposed therebetween, a battery module in which performance degradation and failure are suppressed by specifying the aspect ratio of the main surface of the battery cell, the physical properties of the buffer sheet, and the like is known (see Patent Document 1).

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In a battery module in which a plurality of battery cells are stacked with a member such as a sheet interposed therebetween, in a stack structure in which a laminate including battery cells and a heat insulating member is constrained in a state where pressure is applied in the stacking direction, local stress concentration may occur in the battery cells. As a result, deformation of the battery cells progresses, which may cause problems in the manufacturing of the battery module, such as displacement of terminal holes of terminals included in the battery cells.

[0006] An object of an embodiment of the present disclosure to solve is to provide a method for manufacturing an electricity storage module that suppresses deformation of electricity storage cells in a battery module having a stack structure including electricity storage cells and a heat insulating member. [Means for solving the problem]

[0007] The means for solving the problem include the following: <1> A method for manufacturing an energy storage module comprising a plurality of energy storage cells stacked along a first direction and at least one heat insulating member disposed between two adjacent energy storage cells, the method comprising: pressing a region of the heat insulating member in the thickness direction of the heat insulating member, at least a region including a non-identical position portion that overlaps in the first direction with a portion of at least one adjacent energy storage cell in which electrodes are not housed; and arranging the heat insulating member such that the portion of the heat insulating member in which electrodes are not housed and the pressed portion of the heat insulating member overlap in the first direction. <2> The pressing process involves pressing the entire insulation material in the direction of its thickness. <1> A method for manufacturing an energy storage module as described above. <3> The pressing process includes, for the thermal insulation member, not pressing at least a portion of the portion of the thermal insulation member that overlaps in the first direction with the portion of the thermal insulation member in which electrodes are housed in an adjacent energy storage cell, or pressing in the thickness direction of the thermal insulation member with a pressing pressure smaller than that applied to the portion at a different location. <1> A method for manufacturing an energy storage module as described above. <4> The process includes restraining a stack of energy storage cells, which includes multiple energy storage cells and an insulating member placed between two adjacent energy storage cells, while applying pressure in a first direction. <1> ~ <3> A method for manufacturing an energy storage module as described in any one of the following. <5> The pressing process includes pressing the thermal insulation member with a pressing pressure greater than or equal to the pressure in the first direction used to restrain the energy storage cell stack. <4> A method for manufacturing an energy storage module as described above. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, a method for manufacturing an energy storage module is provided that suppresses deformation of the energy storage cells in a stacked battery module comprising energy storage cells and heat insulating members. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic view of the energy storage cell as seen from the stacking direction. [Figure 2] Figure 2 is a schematic view of each of the two energy storage cells forming the energy storage cell group, as seen from the stacking direction. [Figure 3] Figure 3 is an explanatory diagram illustrating the position of electrodes housed in an energy storage cell, and shows an explanatory diagram of an energy storage cell group consisting of two stacked energy storage cells viewed from the side of the energy storage cell. [Figure 4] Figure 4 is a schematic view of the thermal insulation material as seen from the stacking direction. [Figure 5] Figure 5 is an explanatory diagram showing a stack of energy storage cells manufactured by the energy storage module manufacturing method according to this disclosure, viewed from the side of the energy storage module. [Figure 6] Figure 6 is an explanatory diagram showing a stack of energy storage cells manufactured by a conventional energy storage module manufacturing method, viewed from the side of the energy storage module. [Modes for carrying out the invention]

[0010] This disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical concept of this disclosure. In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In this disclosure, when embodiments are described with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the sizes of the components are not limited thereto. In this disclosure, "energy storage cell" means a secondary battery cell, and "energy storage module" means a secondary battery module.

[0011] <Manufacturing method for energy storage modules> The manufacturing method of the energy storage module according to this disclosure will be explained below with reference to Figures 1 to 5. A method for manufacturing an energy storage module according to this disclosure comprises a plurality of energy storage cells stacked along a first direction and at least one heat insulating member disposed between two adjacent energy storage cells, and comprises a pressing step and an arrangement step. In the pressing step, at least a portion of the heat insulating member that includes a non-identical position portion that overlaps in the first direction with a portion of at least one adjacent energy storage cell in which electrodes are not housed is pressed in the thickness direction of the heat insulating member. In the arrangement step, the heat insulating member is arranged such that the portion of the heat insulating member in which electrodes are not housed is overlapped with the pressed portion of the heat insulating member in the first direction. The first direction is the stacking direction of the energy storage cells and the heat insulating member. The pressing step and the arrangement step are performed in this order.

[0012] (Configuration of the energy storage module) The energy storage module comprises multiple energy storage cells. Each energy storage cell only needs to have an electrode portion that is substantially solid when viewed from the direction in which pressure is applied during restraint, due to the presence of electrodes inside, and an unelectroded portion other than the electrode portion that contains internal space. The configuration, size, and type of the energy storage cell are not particularly limited. The direction in which pressure is applied during restraint is the first direction, i.e., the stacking direction of the energy storage cells. The multiple energy storage cells may include those of the same type or those of different types. From the viewpoint of improving battery performance through restraint, it is preferable that the energy storage cells are secondary solid-state batteries.

[0013] As shown in FIG. 1, an electricity storage cell 10, which is an example of an electricity storage cell, is an electricity storage cell for a solid battery, has a rectangular plate shape, and includes a main surface 11 along a plane YZ formed by a direction Y and a direction Z orthogonal to the stacking direction. When viewed from the stacking direction, the electricity storage cell 10 has an electrode portion 12 in which an electrode is present inside, and a non-electrode portion 13 in which members other than the electrode are present inside. In the electrode portion 12, the electrode is substantially solidly housed inside the exterior body of the electricity storage cell 10, and there is substantially no space in the stacking direction. On the other hand, in the non-electrode portion 13, a gathered portion of electrode foil and the like are housed inside the exterior body of the electricity storage cell 10, and a space exists in the stacking direction.

[0014] The terminal structure of the electricity storage cell is not limited. Either a configuration in which the main surface 11 is used as a terminal, or a configuration in which a terminal is provided for use is applicable. In the electricity storage cell 10, a negative electrode terminal 14 is provided at one end, and a positive electrode terminal 15 is provided at the other end.

[0015] A heat insulating member is disposed between two adjacent electricity storage cells. The arrangement form of the electricity storage cells and the heat insulating member is not limited, as long as the heat insulating member is disposed between two adjacent electricity storage cells. Therefore, the configuration may be, for example, that one electricity storage cell and a heat insulating member are alternately arranged, a heat insulating member is disposed between an electricity storage cell group formed by stacking a predetermined number of two or more electricity storage cells and another same electricity storage cell group, or a heat insulating member is disposed between one electricity storage cell and a plurality of electricity storage cell groups. In the method for stacking electricity storage cells, from the viewpoint of load balance, it is preferable to stack the electricity storage cells such that the positions of the non-electrode portions 13 are not biased.

[0016] As shown in FIG. 2, the electricity storage cell group may include two electricity storage cells, namely the electricity storage cell 10 and the electricity storage cell 20. The electricity storage cell 10 and the electricity storage cell 20 are the same type of electricity storage cell. In both the electricity storage cell 10 and the electricity storage cell 20, the non-electrode portion 13 exists on the negative electrode terminal 14 side. The electricity storage cell 10 and the electricity storage cell 20 are the same type of electricity storage cell, and one of them is inverted and stacked.

[0017] As shown in Figure 3, the electricity storage cell 10 and the electricity storage cell 20 house electrodes. The electrodes include an electrode laminate in which a current collector layer, an active material layer, an electrolyte layer, and the like are stacked. The electricity storage cell 10 houses an electrode laminate 31, and the electricity storage cell 20 houses an electrode laminate 32. In the electricity storage cell group, when viewed from the stacking direction, the electrode portions of the electricity storage cell 10 and the electricity storage cell 20 form a co-position portion 33 overlapping in the stacking direction. By forming the co-position portion 33, when an electricity storage cell laminate is formed using the electricity storage cell group, appropriate pressure can be applied to restrain the entire electrode laminate present at least in the co-position portion 33. Note that the electricity storage cell laminate refers to a laminate configured by stacking electricity storage cells and heat insulating members. From the viewpoint of the performance of the electricity storage module, it is preferable to form the electricity storage cell laminate so as to form the co-position portion 33.

[0018] The electricity storage module includes the electricity storage cell laminate. The electricity storage module preferably includes a restraining member for restraining the electricity storage cell laminate in a state where pressure is applied thereto.

[0019] (Method for Manufacturing Electricity Storage Module) As shown in Figure 6, conventional methods for manufacturing energy storage modules typically involve simply stacking and restraining energy storage cells and thermal insulation materials. In this method, the thickness of the thermal insulation material is uneven, the load is not uniformly distributed, and localized stress concentration is likely to occur at specific locations. As a result, deformation of the energy storage cells progresses, and misalignment of the terminal holes in the stacked cells is likely to occur. More specifically, in conventional methods for manufacturing energy storage modules, in energy storage cells adjacent to the thermal insulation material, the unelectrode portion of the energy storage cell may deform, bending with the end of the electrode portion as a fulcrum. Such deformation of the energy storage cell can cause problems such as misalignment of the terminal holes provided at the end of the energy storage cell. Therefore, in the manufacturing process of energy storage modules, it may be necessary to perform steps such as correcting the deformation of the energy storage cells and correcting the misalignment of the terminal holes before connecting the terminal holes, which can make it difficult to manufacture energy storage modules efficiently. The energy storage module shown in Figure 6 includes an energy storage cell stack 100 which comprises an energy storage cell group 101 containing two energy storage cells, a heat insulating member 102, and an energy storage cell group 103 containing two energy storage cells, stacked in this order. This is an example of a stack manufactured without a prior pressing process on the heat insulating member 102. During restraint, pressure is applied to the pressurizing section 55, which includes the electrode section 12, in the stacking direction X.

[0020] The inventor focused on the load applied to each component during restraint in order to suppress deformation of the energy storage cell during restraint. The inventor obtained the following finding: When the heat insulating member is restrained, it deforms due to the load in the part where restraint pressure is applied, and a load is applied in the part where restraint pressure is not applied. In an energy storage cell adjacent to the heat insulating member, a localized load is applied near the end of the electrode portion 12, that is, in the region of the unelectrode portion 13 close to the electrode portion 12, due to the load of the heat insulating member as described above. As a result, a bending moment is generated in the energy storage cell. This causes the unelectrode portion 13 of the energy storage cell adjacent to the heat insulating member to deform by bending with the end of the electrode portion 12 as the fulcrum, and the end of the energy storage cell shifts from its original position. It is presumed that the terminal holes provided at the end of the energy storage cell shift in this way.

[0021] In addressing the above problem, the inventors discovered that by pre-pressing specific parts of the thermal insulation member, deformation of the energy storage cell during restraint can be suppressed. Although the mechanism by which this effect is achieved is not clear, it is presumed that by pre-pressing specific parts of the thermal insulation member, the concentration of load applied to the thermal insulation member during restraint can be distributed without impairing the function of the thermal insulation member, thereby appropriately suppressing stress concentration in the energy storage cell.

[0022] (Pressing process) In the pressing process, at least a region of the heat insulating material that includes a non-identical position portion that overlaps with the unelectrode portion in the stacking direction in at least one adjacent energy storage cell is pressed in the thickness direction of the heat insulating material. Each adjacent energy storage cell has an identical position portion and a non-identical position portion other than the identical position portion. The heat insulating material also has identical position portions and non-identical position portions corresponding to the electrode portions and unelectrode portions of the adjacent energy storage cell. Therefore, the pressing position of the heat insulating material differs depending on the adjacent energy storage cell.

[0023] In this disclosure, "pressing" means the process of applying mechanical pressure in the thickness direction of the thermal insulation material. Pressing methods include, but are not limited to, roll pressing, stamping, and compression molding. In the pressing process, a constant pressure is applied to the portion of the thermal insulation material that includes non-contiguous locations, thereby deforming it in the thickness direction. This pressing may be carried out within an appropriate pressure range depending on the characteristics of the thermal insulation material, such as its compression ratio.

[0024] The insulating material should exhibit properties such as thermal insulation performance that suppresses heat transfer between adjacent energy storage cells and prevents localized temperature rises, and elasticity that absorbs pressure changes due to the expansion and contraction of energy storage cells and improves the stability of the energy storage module. The shape, material, size, etc., of the insulating material are not limited. The material of the insulating material preferably has voids so as to reduce thermal conductivity and be appropriately compressed by a load due to pressing or restraint.

[0025] From the viewpoint of performing its function as an insulating material and suppressing deformation of the energy storage cell, the insulating material is preferably in the shape of a rectangular plate that is substantially the same as the shape of the energy storage cell. The shape of the insulating material may be adjusted insofar as it performs its function as an insulating material, from the viewpoint of suppressing deformation of the energy storage cell. The shape of the insulating material may be a rectangular shape that is the same size as the electrode portion of the adjacent energy storage cell, that is, the length in direction Y and direction X of the electrode portion is the same as the length in direction Y and direction Z of the insulating material. By having the insulating material and the electrode portion of the adjacent energy storage cell be of similar size, stress concentration at non-identical locations of the insulating material can be eliminated, thereby suppressing deformation of the energy storage cell due to stress concentration.

[0026] The insulating material may have a smooth surface, or it may have a corrugated surface, etc. The insulating material may be a single porous structure with voids, or a multilayer insulating structure combining different layers. The insulating material may be formed from an inorganic material, an organic material, or a composite material containing different materials. The insulating material may be selected according to the arrangement of the energy storage cells, the type of energy storage cells, the layered structure of the energy storage cell stack, the load applied during restraint, the type of energy storage module, etc.

[0027] The pressing conditions in the pressing process should be such that the shape of the pressed insulating material deforms to be at least thinner compared to before pressing, depending on the type of insulating material. From the viewpoint of suppressing deformation of the energy storage cells, it is preferable that the difference in the overall thickness of the insulating material is small when it is assembled into an energy storage cell laminate. By using pressed insulating material, it is preferable that the difference in thickness between parts at the same position and parts at different positions is small when it is assembled into an energy storage cell laminate. Similarly, from the viewpoint of suppressing deformation of the energy storage cells, it is preferable that the difference in thickness between parts at the same position and parts at different positions of the insulating material is small when the energy storage cell laminate is restrained by applying pressure in the stacking direction. For insulating material arranged in an energy storage module, it is preferable that the difference in overall thickness is small from the viewpoint of suppressing deformation of the energy storage cells.

[0028] From the viewpoint of suppressing deformation of the energy storage cells, it is preferable that the pressing process presses the heat insulating material with a pressing pressure greater than the pressure in the stacking direction when restraining the energy storage cell stack.

[0029] As shown in Figure 4, the heat insulating member 40 has non-identical position portions 41 that overlap the unelectrode portion 13 in the stacking direction, corresponding to adjacent energy storage cells 10 and 20. Of the two non-identical position portions 41 located at both ends of the heat insulating member 40, one corresponds to the energy storage cell 10, and the other corresponds to the energy storage cell 20. In the pressing process, at least the non-identical position portions 41 of the heat insulating member 40 are pressed in the thickness direction of the heat insulating member 40. Therefore, the regions of the heat insulating member 40 that include each of the two non-identical position portions 41 are pressed in the pressing process.

[0030] In the heat insulating member 40, the position that overlaps with the electrode portion 12 in the stacking direction corresponding to the adjacent energy storage cell 10 is the identical position portion 42. From the viewpoint of suppressing deformation of the energy storage cell, the identical position portion 42 may or may not be pressed. Furthermore, the pressing process for pressing the heat insulating member 40 only needs to include at least the non-identical position portion 41, and the entire heat insulating member 40, including the non-identical position portion 41 and the identical position portion 42, may be pressed in the thickness direction of the heat insulating member 40. Alternatively, the entire non-identical position portion 41 and a part of the identical position portion 42 may be pressed. It is preferable that the thickness of the non-identical position portion 41 and the thickness of the identical position portion 42 are the same after pressing, in other words, the thickness of the heat insulating member 40 is uniform in the in-plane direction.

[0031] During restraint, pressure is applied to the same-position portion 42 of the heat insulating member. From the viewpoint of ensuring that the heat insulating member functions properly, the process of pressing the heat insulating member may include pressing at least the non-same-position portion 41 of the heat insulating member, while leaving at least a portion of the same-position portion 42 unpressed. Similarly, the heat insulating member may be pressed including at least the non-same-position portion 41, and the same-position portion 42 may be pressed with a pressure smaller than the pressure applied to the non-same-position portion 41.

[0032] (Placement process) In the placement process, the insulating material is positioned such that the portion of the energy storage cell adjacent to at least one of the cells where electrodes are not housed, i.e., the unelectrode portion, and the pressed portion of the insulating material, i.e., the non-identical portion, overlap in the stacking direction.

[0033] In the pressing process, by using a heat insulating member that has been pre-pressed at least non-identical locations, and in the placement process, by placing the pressed portion of the heat insulating member in the stacking direction with the unelectrode portion to form a stack of energy storage cells, it is estimated that localized stress concentration in the heat insulating member is suppressed when pressure is applied to restrain the stack of energy storage cells. In the same location, the heat insulating member is stacked adjacent to the energy storage cells, thereby performing its function as a heat insulating member while suppressing localized stress concentration in the heat insulating member, and thus suppressing deformation of the energy storage cells.

[0034] As described above, the configuration of the energy storage cell stack is not limited, and the number of energy storage cells, the number of insulating materials, the configuration of the energy storage cell stack, etc., can be selected as appropriate.

[0035] As shown in Figure 5, the energy storage cell stack 50 included in the energy storage module is constructed by stacking an energy storage cell group 51 containing two energy storage cells, an insulating member 52, and an energy storage cell group 53 containing two energy storage cells in this order. The non-identical positions 41 of the insulating member 52 are pressed before stacking. The insulating member 52 includes a pressed portion and an unpressed portion at the identical position 54. Pressure is applied to the pressurized portion 55 by restraint, including the identical position 54 common to the energy storage cells and the insulating member. In the energy storage cell stack 50 included in the energy storage module, the insulating member 52 is pre-pressed, which suppresses deformation of the energy storage cells. Therefore, misalignment is suppressed at the terminals of each energy storage cell, and misalignment is also suppressed at the terminal holes.

[0036] In the method for manufacturing an energy storage module according to this disclosure, when a stack of energy storage cells having a stack structure is formed by restraining them while applying pressure in the stacking direction, deformation of the unelectrode portion of an energy storage cell adjacent to a heat insulating member, such as bending with the end of the electrode portion as a fulcrum, is suppressed, and displacement of the terminal portion of the energy storage cell is also suppressed.

[0037] (Restriction process) The method for manufacturing an energy storage module according to this disclosure may include a restraining step. The restraining step is a step of restraining an energy storage cell stack, which includes a plurality of energy storage cells and an insulating member placed between two adjacent energy storage cells, while applying pressure in the stacking direction. The method for manufacturing an energy storage module that includes a restraining step can significantly suppress the deformation of the energy storage cells.

[0038] In the restraining process, the energy storage cell stack manufactured through the pressing and placement processes is restrained under pressure in the stacking direction. The pressure conditions may be determined as appropriate from the viewpoint of the performance of the energy storage module. As mentioned above, from the viewpoint of suppressing deformation of the energy storage cells, it is preferable that the pressure due to restraining is less than the pressing pressure of the heat insulating material in the pressing process. For example, if the pressing pressure of the heat insulating material in the pressing process is 4 MPa, it is preferable that the pressure due to restraining be 2 MPa.

[0039] <Energy storage module> The energy storage module according to this disclosure comprises a plurality of energy storage cells stacked along a first direction and at least one heat insulating member disposed between two adjacent energy storage cells, wherein the portion of the heat insulating member that includes a non-identical position portion that overlaps in the first direction with a portion in at least one adjacent energy storage cell where electrodes are not housed is compressed in the thickness direction of the heat insulating member.

[0040] The energy storage module according to this disclosure can suppress deformation of energy storage cells. Even when an energy storage cell stack comprising multiple energy storage cells and an insulating member is restrained by a restraining member under pressure in the stacking direction, deformation of the energy storage cells is suppressed, thereby improving the manufacturing cost and stability of the energy storage cell module.

[0041] <Types and applications of energy storage modules> In the method for manufacturing an energy storage module according to this disclosure, it is preferable that the energy storage cell be a solid-state battery because it exhibits a significant effect in suppressing deformation of the energy storage cell. The type of solid-state battery is not particularly limited, but is typically a lithium-ion battery. It is preferable that the solid-state battery be a secondary battery. The solid-state battery may be a semi-solid-state battery having a gel layer containing an electrolyte and a polymer between the electrode and the solid electrolyte, or it may be an all-solid-state battery having a layer of solid electrolyte. It is preferable that the solid-state battery be an all-solid-state battery because it exhibits a significant effect in suppressing deformation of the energy storage cell.

[0042] In the method for manufacturing an energy storage module according to this disclosure, the application of the energy storage module is not particularly limited. Typical applications are diverse, including vehicles, electronic equipment, and electric storage systems, but it is particularly suitable for use as a power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). It can also be used as a power source for mobile vehicles such as railways, ships, and aircraft, as well as for information processing equipment. [Examples]

[0043] The present disclosure will be described in more detail below with reference to examples, but the invention of the present disclosure is not limited to these examples.

[0044] [Comparative Example 1, Example 1, and Example 2] Three identical thermal insulation members, A-1, A-2, and A-3, of approximately the same size as the energy storage cell, were prepared. In Comparative Example 1 (thermal insulation member A-1), no pressing process was performed, and it was used as is. In Example 1 (thermal insulation member A-2), the entire surface of thermal insulation member A-2 was pressed with a pressure of 2 MPa in the thickness direction. In Example 2 (thermal insulation member A-3), the non-identical locations of thermal insulation member A-3 were pressed with a pressure of 4 MPa in the thickness direction, while the identical locations were not pressed.

[0045] A power storage module was fabricated using the following method with the heat insulating members A-1, A-2, and A-3. The configuration of the power storage module is as follows: Two groups of power storage cells, each consisting of two power storage cells stacked together, were prepared. Each power storage cell group consisted of two power storage cells stacked together such that the terminal holes of each power storage cell approximately overlapped. A power storage cell stack was formed by placing heat insulating member A-1, A-2, or A-3 between the power storage cell groups. Heat insulating members A-2 and A-3 were positioned so that the portion of the power storage cell that does not contain electrodes overlapped with the pressed portion of each heat insulating member in the stacking direction. Subsequently, pressure (2 MPa) was applied to the stacking direction of the power storage cell stack using a restraining member to restrain it and fabricate the power storage module.

[0046] After the constraints were applied, each of the fabricated energy storage modules was visually inspected from the side direction (Z direction, see Figure 5 or Figure 6) to check for any misalignment in the terminal holes that were arranged to overlap. In the case of using thermal insulation member A-2 in Example 1 and thermal insulation member A-3 in Example 2, based on the manufacturing method of the energy storage module according to this disclosure, there was no misalignment of the two terminal holes, and they remained in their original arrangement. However, in the case of using thermal insulation member A-1 in Comparative Example 1, misalignment of the two terminal holes occurred, and more than half of the holes were blocked. These results are shown in Table 1.

[0047] [Table 1]

[0048] [Reference Examples 1 and 2] Two identical thermal insulation members, A-4 and A-5, of approximately the same size as the electrode portion of the energy storage cell, were prepared. In Reference Example 1 (thermal insulation member A-4), thermal insulation member A-4 was used as is without any pressing process. In Reference Example 2 (thermal insulation member A-5), thermal insulation member A-5 was pressed with a pressure of 2 MPa in the thickness direction across its entire surface.

[0049] A power storage module was fabricated in the same manner as in Example 1, using thermal insulation members A-4 and A-5. After restraining, the alignment of the terminal holes, which were positioned to overlap, was checked for any misalignment, in the same manner as in Example 1. In both the case using thermal insulation member A-4 and the case using thermal insulation member A-5, there was no misalignment of the two terminal holes, and they remained in their original position. These results are shown in Table 2.

[0050] [Table 2] [Explanation of symbols]

[0051] 10,20 Energy storage cell, 11 Main surface, 12 Electrode section, 13 Unelectroded section, 14 Negative terminal, 15 Positive terminal, 31,32 Electrode stack, 33,42,54 Same position section, 40,52,102 Heat insulating member, 41 Non-same position section, 50,100 Energy storage cell stack, 51,53,101 Energy storage cell group, 55 Pressurized section, X First direction, Y,Z Directions orthogonal to the first direction

Claims

1. A method for manufacturing an energy storage module comprising a plurality of energy storage cells stacked along a first direction, and at least one heat insulating member disposed between two adjacent energy storage cells, The process of pressing, in the thickness direction of the heat insulating member, at least a region of the heat insulating member that includes a non-identical position portion that overlaps in the first direction with a portion in at least one of the adjacent energy storage cells where electrodes are not housed, The process includes a step of arranging the heat insulating member such that the portion of the heat insulating member in at least one adjacent energy storage cell where electrodes are not housed and the pressed portion of the heat insulating member overlap in a first direction. A method for manufacturing energy storage modules.

2. The method for manufacturing an energy storage module according to claim 1, wherein the pressing step involves pressing the entire heat insulating member in the thickness direction of the heat insulating member.

3. The method for manufacturing an energy storage module according to claim 1, wherein the pressing step includes not pressing at least a portion of the heat insulating member that is in the same position as the portion of the heat insulating member that is adjacent to the energy storage cell in which electrodes are housed, in the first direction, or pressing the heat insulating member in the thickness direction with a pressing pressure smaller than the pressing pressure in the non-same position portion.

4. A method for manufacturing an energy storage module according to claim 1, comprising the step of restraining an energy storage cell laminate, which includes a plurality of energy storage cells and the heat insulating member disposed between two adjacent energy storage cells, while applying pressure in a first direction.

5. The method for manufacturing an energy storage module according to claim 4, wherein the pressing step includes pressing the heat insulating member with a pressing pressure greater than or equal to the pressure in the first direction when restraining the energy storage cell stack.

Images