Method for manufacturing a power storage module

Abstract

To provide a power storage module with a novel configuration, capable of leveling high rate resistances of a plurality of power storage devices.SOLUTION: A manufacturing method of a power storage module includes: a preparation step of preparing a first power storage device 110 having a first electrode body molded at a relatively low press pressure and a second power storage device 120 having a second electrode body molded at a relatively high press pressure; a temperature distribution prediction step of predicting a temperature distribution in a power storage module 500 when a plurality of a power storage devices 100 are charged and discharged; and a construction step of constructing a power storage module by disposing the first power storage device 110 in a low-temperature region A1 with relatively low temperature and disposing the second power storage device 120 in a high-temperature region A2 with relatively high temperature, based on the temperature distribution.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a power storage module including a plurality of power storage devices.

Background Art

[0002] Conventionally, in vehicle drive power sources and the like, a power storage module formed by electrically connecting a plurality of power storage devices (single cells) has been widely used. As related prior art documents, Patent Documents 1 and 2 can be cited.

[0003] For example, Patent Document 1 discloses a power storage module having a plurality of sub-modules and a housing that houses the plurality of sub-modules at predetermined positions. In Patent Document 1, each of the plurality of sub-modules includes a cell group in which a plurality of power storage devices (single cells) are arranged, and a restraining member that applies a restraining pressure in the arrangement direction to restrain the cell group. And, there is a region in the housing that tends to become relatively low in temperature, and the sub-module arranged in the region that tends to become low in temperature is configured such that the restraining pressure of the restraining member is relatively lower than that of other sub-modules. Patent Document 1 describes that by reducing the restraining pressure on the power storage device in a region (a region that tends to become low in temperature) where the high-rate resistance is likely to decrease in this way, the high-rate resistance (increase in resistance when high-rate charge and discharge are repeated) of the plurality of power storage devices can be equalized.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology described in the above Patent Document 1, it is not possible to make the mutual restraint pressures different for a plurality of power storage devices included in one cell group. Therefore, according to the study by the present inventors, when a temperature distribution occurs within the cell group, it may be difficult to equalize the high-rate resistance of the plurality of power storage devices. Further, since a restraint member is essential for each cell group, the restraint member takes up space and the volume energy density of the entire power storage module decreases. For example, when the power storage module is mounted on a moving body such as a vehicle, there is a risk that the weight increases and the fuel consumption deteriorates.

[0006] The present invention has been made in view of the above circumstances, and its main object is to provide a power storage module having a novel configuration capable of equalizing the high-rate resistance of a plurality of power storage devices and a method for manufacturing the same.

Means for Solving the Problems

[0007] The present invention provides a method for manufacturing a power storage module including a plurality of power storage devices. Each of the plurality of power storage devices included in this power storage module has a flat rectangular battery case and an electrode body accommodated in the battery case and having a flat portion facing the flat surface of the battery case. And this manufacturing method includes a preparation step of preparing, as a plurality of power storage devices, a first power storage device having a first electrode body formed with a relatively low pressing pressure and a second power storage device having a second electrode body formed with a relatively high pressing pressure, a temperature distribution prediction step of predicting the temperature distribution in the power storage module when the plurality of power storage devices are charged and discharged, and a construction step of constructing the power storage module by arranging the first power storage device in a relatively low-temperature region and the second power storage device in a relatively high-temperature region based on the temperature distribution.

[0008] As a result of various studies by the present inventors, it has been found that a power storage device having an electrode body with a low pressing pressure during manufacturing is relatively superior in high-rate tolerance compared to a power storage device having an electrode body with a high pressing pressure. Therefore, in the present invention, a first power storage device having an electrode body with a relatively low pressing pressure (high high-rate tolerance) is arranged in a low-temperature region where the high-rate tolerance is likely to decrease. Thereby, the high-rate tolerance of a plurality of power storage devices can be equalized. As a result, the high-rate tolerance of the entire power storage module can be improved. Further, unlike the technique of Patent Document 1, since there is no need to be confined to the framework of a "cell group", the high-rate tolerance of individual power storage devices can be adjusted flexibly. Furthermore, since the number of restraining members can be reduced compared to the technique of Patent Document 1, the volume energy density and fuel efficiency can also be improved.

Brief Description of the Drawings

[0009]

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Best Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the technology disclosed herein will be described with reference to the drawings as appropriate. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present invention (for example, general configurations and manufacturing processes of power storage modules and power storage devices that do not characterize the present invention) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The manufacturing method of the power storage module disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field.

[0011] In the following drawings, members and parts having the same function are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified. Also, the notation "A to B" indicating a range in this specification includes the meaning of "not less than A and not more than B", as well as the meaning of "preferably greater than A" and "preferably less than B".

[0012] Hereinafter, an embodiment of the manufacturing method of the power storage module disclosed herein will be described. In the following, after explaining the structure of the power storage module to be manufactured, the specific manufacturing method will be described.

[0013] [Power Storage Module] FIG. 1 is a perspective view schematically showing a power storage module 500. The power storage module 500 here includes a plurality of power storage devices 100, a plurality of spacers 200, and a restraint mechanism 300. However, the plurality of spacers 200 and the restraint mechanism 300 are not essential and can be omitted in other embodiments.

[0014] In the following description, the reference signs L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, up, and down, respectively, and the reference signs X, Y, and Z in the drawings represent the short side direction, the long side direction orthogonal to the short side direction, and the up-down direction of the power storage device 100, respectively. The short side direction X is also the arrangement direction of the power storage devices 100. However, these are merely directions for convenience of explanation and do not limit the installation form of the power storage module 500 in any way.

[0015] The restraint mechanism 300 is a member that restrains a plurality of power storage devices 100. Here, there is one restraint mechanism 300. The restraint mechanism 300 is configured to apply an equal restraint pressure to all the power storage devices 100 and the spacers 200 from the arrangement direction X. The restraint mechanism 300 includes a pair of end plates 310, a pair of side plates 320, and a plurality of screws 330. The pair of end plates 310 and the pair of side plates 320 can also be regarded as a housing that houses a plurality of power storage devices 100. The pair of end plates 310 and the pair of side plates 320 are preferably made of metal.

[0016] The pair of end plates 310 are arranged at both ends of the power storage module 500 in the arrangement direction X. The pair of end plates 310 sandwich a plurality of power storage devices 100 and a plurality of spacers 200 in the arrangement direction X. The pair of side plates 320 bridge the pair of end plates 310. The pair of side plates 320 are fixed to the end plates 310 by a plurality of screws 330 such that the restraint load is about 10 to 15 kN, for example. As a result, a uniform restraint load is applied to the plurality of power storage devices 100 from the arrangement direction X, and the plurality of power storage devices 100 are integrally held. However, the configuration of the restraint mechanism is not limited to this. The restraint mechanism 300 may include, for example, a plurality of restraint bands or binding bars instead of the side plates 320.

[0017] The spacer 200 is here arranged respectively between a plurality of power storage devices 100 in the array direction X. That is, in the array direction X, the power storage devices 100 and the spacers 200 are arranged alternately. However, when the power storage module 500 does not include the spacer 200, the power storage devices 100 adjacent to each other in the array direction X may be in contact (direct contact). The spacer 200 preferably includes a porous structure portion through which a fluid (typically a gas such as air) can pass.

[0018] The power storage device 100 is a device capable of repeated charge and discharge. In this specification, the "power storage device" is a concept including secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors such as lithium-ion capacitors and electric double-layer capacitors. The plurality of power storage devices 100 are here arranged between a pair of end plates 310 along the array direction X (in other words, the thickness direction X of the power storage device 100). The plurality of power storage devices 100 are preferably constrained by a constraint mechanism 300. Note that the shape, size, number, etc. of the plurality of power storage devices 100 are not limited to the embodiments disclosed in FIG. 1 and can be changed as appropriate.

[0019] Although not shown here, when the power storage module 500 is in use, the plurality of power storage devices 100 are electrically connected to each other by a conductive member such as a bus bar. The connection method is not particularly limited and may be, for example, series, parallel, or multi-series multi-parallel, etc. In a preferred embodiment, the plurality of power storage devices 100 are connected in series. Thereby, for example, the output characteristics can be preferably improved to a level suitable for use in a moving body such as a vehicle. Also, in the case of series connection, deterioration of the performance of some of the power storage devices 100 is likely to lead to deterioration of the performance of the entire power storage module 500. Therefore, it is particularly effective to apply the technology disclosed herein.

[0020] FIG. 2 is a perspective view of the power storage device 100. As can be seen from FIGS. 1 and 2, the plurality of power storage devices 100 are all flat rectangular shapes, and here they have the same shape. The plurality of power storage devices 100 are arranged such that the long side walls 12b described later are parallel to each other. The plurality of power storage devices 100 are arranged in the arrangement direction X such that the long side walls 12b face each other via the spacer 200 here.

[0021] FIG. 3 is a schematic longitudinal sectional view taken along line III-III of FIG. 2. As shown in FIG. 3, the power storage device 100 includes, here, a battery case 10, an electrode body 20, a positive electrode terminal 30, a negative electrode terminal 40, and a non-aqueous electrolyte (not shown). The power storage device 100 is configured by housing the electrode body 20 and the non-aqueous electrolyte in the battery case 10 to which the positive electrode terminal 30 and the negative electrode terminal 40 are attached. The power storage device 100 is typically a non-aqueous electrolyte secondary battery, and here it is a lithium-ion secondary battery. When the power storage device 100 is a lithium-ion secondary battery, it is particularly effective to apply the technology disclosed herein.

[0022] The battery case 10 is a container for housing the electrode body 20 and the non-aqueous electrolyte. As shown in FIG. 2, the battery case 10 has a flat and bottomed rectangular parallelepiped shape (rectangular shape) outer appearance here. The material of the battery case 10 may be the same as that conventionally used, and there is no particular limitation. The battery case 10 is made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, or the like. As shown in FIG. 3, the battery case 10 includes an exterior body 12 having an opening 12h and a sealing plate (lid) 14 for sealing the opening 12h. As shown in FIG. 2, the exterior body 12 includes a substantially rectangular bottom wall 12a having long sides and short sides, a pair of long side walls 12b extending from the long sides of the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the short sides of the bottom wall 12a and facing each other. The long side wall 12b is flat.

[0023] The sealing plate 14 is a plate-shaped member. The sealing plate 14 is substantially rectangular. As shown in FIG. 3, the sealing plate 14 is attached to the exterior body 12 so as to close the opening 12h of the exterior body 12. The battery case 10 is integrated by joining (preferably by welding) the sealing plate 14 to the periphery of the opening 12h of the exterior body 12. The battery case 10 is hermetically sealed. The sealing plate 14 is provided with a liquid injection hole 15 and two terminal lead-out holes 18 and 19. The liquid injection hole 15 is for injecting a non-aqueous electrolyte after assembling the sealing plate 14 to the exterior body 12. The liquid injection hole 15 is sealed by a sealing member 16. The terminal lead-out holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z.

[0024] The positive electrode terminal 30 is disposed at one end in the long side direction Y of the sealing plate 14 (the left end portion in FIGS. 2 and 3), and the negative electrode terminal 40 is disposed at the other end in the long side direction Y of the sealing plate 14 (the right end portion in FIGS. 2 and 3). As shown in FIG. 3, the positive electrode terminal 30 and the negative electrode terminal 40 respectively extend from the inside to the outside of the sealing plate 14 through the terminal lead-out holes 18 and 19. Here, the positive electrode terminal 30 and the negative electrode terminal 40 are caulked to the peripheral portion surrounding the terminal lead-out holes 18 and 19 of the sealing plate 14 by caulking. Caulking portions 30c and 40c are formed at the ends on the side of the exterior body 12 of the positive electrode terminal 30 and the negative electrode terminal 40 (the lower end portion in FIG. 3). Thereby, the positive electrode terminal 30 and the negative electrode terminal 40 are fixed to the sealing plate 14.

[0025] As shown in FIG. 3, the positive electrode terminal 30 is electrically connected to the positive electrode tab group 23 of the electrode body 20 via the positive electrode current collector 50 inside the exterior body 12. The positive electrode terminal 30 is insulated from the sealing plate 14 by the internal insulating member 80 and the gasket 90. The negative electrode terminal 40 is electrically connected to the negative electrode tab group 25 of the electrode body 20 via the negative electrode current collector 60 inside the exterior body 12. The negative electrode terminal 40 is insulated from the sealing plate 14 by the internal insulating member 80 and the gasket 90.

[0026] As shown in FIGS. 2 and 3, a plate-shaped positive electrode external conductive member 32 and a negative electrode external conductive member 42 are attached to the outer surface of the sealing plate 14. The positive electrode external conductive member 32 is electrically connected to the positive electrode terminal 30. The negative electrode external conductive member 42 is electrically connected to the negative electrode terminal 40. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are members to which conductive members such as bus bars for electrically connecting a plurality of power storage devices 100 to each other are attached. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are insulated from the sealing plate 14 by an external insulating member 92. The power storage module 500 is connected in series, for example, by electrically connecting the positive electrode external conductive member 32 of one power storage device 100 and the negative electrode external conductive member 42 of the other power storage device 100 among adjacent power storage devices 100 in the array direction X with a bus bar or the like.

[0027] FIG. 4 is a schematic diagram showing the configuration of the electrode body 20. Further, FIG. 5 is a schematic longitudinal sectional view taken along the line V-V of FIG. 3. As shown in FIG. 4, the electrode body 20 includes a positive electrode 22, a negative electrode 24, and a separator 26. Here, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are laminated via a strip-shaped separator 26 and wound around a winding axis WL. The electrode body 20 in the present embodiment is a wound electrode body having a flat shape obtained by crushing the wound cylindrical electrode body by pressing. As shown in FIGS. 3 and 5, the electrode body 20 is housed inside the battery case 10 (outer package 12). At this time, as shown in FIG. 5, the flat portion 20a of the flat-shaped electrode body 20 faces the flat surface 10a of the battery case 10 (the long side wall 12b of the outer package 12). Note that the shape of the electrode body 20 is not limited to the wound electrode body described above. For example, the electrode body 20 may be a laminated electrode body in which a plurality of sheet-shaped positive electrodes 22, sheet-shaped negative electrodes 24, and sheet-shaped separators 26 are laminated.

[0028] The configuration of the positive electrode 22 may be the same as that of the prior art. Here, the positive electrode 22 has a positive electrode current collector 22c, a positive electrode active material layer 22a and a positive electrode protective layer 22p fixed on at least one surface of the positive electrode current collector 22c. However, the positive electrode protective layer 22p is not essential and can be omitted in other embodiments. The positive electrode current collector 22c is strip-shaped. The positive electrode current collector 22c is preferably made of metal, and more preferably made of a metal foil. Here, the positive electrode current collector 22c is an aluminum foil.

[0029] A plurality of positive electrode tabs 22t are provided at one end (the left end in FIG. 4) in the long side direction Y of the positive electrode current collector 22c. The plurality of positive electrode tabs 22t protrude toward one side in the long side direction Y (the left side in FIG. 4). The plurality of positive electrode tabs 22t protrude in the long side direction Y more than the separator 26. Here, the positive electrode tab 22t is a part of the positive electrode current collector 22c and is made of a metal foil (aluminum foil). The plurality of positive electrode tabs 22t are laminated at one end (the left end in FIG. 4) in the long side direction Y to form a positive electrode tab group 23. The positive electrode tab group 23 is electrically connected to the positive electrode terminal 30 via the positive electrode current collecting portion 50.

[0030] The positive electrode active material layer 22a is provided in a strip shape along the longitudinal direction of the positive electrode current collector 22c. The positive electrode active material layer 22a contains a positive electrode active material capable of reversibly occluding and releasing charge carriers. Examples of the positive electrode active material include lithium transition metal composite oxides. The positive electrode active material layer 22a may contain optional components other than the positive electrode active material, such as various additive components such as a binder and a conductive material.

[0031] The positive electrode protective layer 22p is provided at the boundary portion between the positive electrode current collector 22c and the positive electrode active material layer 22a in the long side direction Y. The positive electrode protective layer 22p is provided in a strip shape along the positive electrode active material layer 22a. The positive electrode protective layer 22p contains an inorganic filler (for example, alumina). The positive electrode protective layer 22p may contain optional components other than the inorganic filler, such as a conductive material, a binder, and various additive components.

[0032] The configuration of the negative electrode 24 may be the same as that of the conventional one. Here, the negative electrode 24 has a negative electrode current collector 24c and a negative electrode active material layer 24a fixed on at least one surface of the negative electrode current collector 24c. The negative electrode current collector 24c is strip-shaped. The negative electrode current collector 24c is preferably made of metal, and more preferably made of a metal foil. Here, the negative electrode current collector 24c is a copper foil.

[0033] A plurality of negative electrode tabs 24t are provided at one end (the right end in FIG. 4) in the long side direction Y of the negative electrode current collector 24c. The plurality of negative electrode tabs 24t project toward one side in the long side direction Y (the right side in FIG. 4). The plurality of negative electrode tabs 24t project in the long side direction Y more than the separator 26. Here, the negative electrode tab 24t is a part of the negative electrode current collector 24c and is made of a metal foil (copper foil). The plurality of negative electrode tabs 24t are laminated at one end (the right end in FIG. 4) in the long side direction Y to form a negative electrode tab group 25. The negative electrode tab group 25 is provided at a position symmetric to the positive electrode tab group 23 in the long side direction Y. The negative electrode tab group 25 is electrically connected to the negative electrode terminal 40 via the negative electrode current collecting portion 60.

[0034] The negative electrode active material layer 24a is provided in a strip shape along the longitudinal direction of the negative electrode current collector 24c. The length Ln of the negative electrode active material layer 24a in the long side direction Y is preferably the same as or longer than the length Lp of the positive electrode active material layer 22a in the long side direction Y. The negative electrode active material layer 24a contains a negative electrode active material capable of reversibly occluding and releasing charge carriers. Examples of the negative electrode active material include carbon materials such as graphite. The negative electrode active material layer 24a may contain optional components other than the negative electrode active material, such as various additive components such as a binder, a thickener, and a dispersant.

[0035] The separator 26 is disposed between the positive electrode 22 and the negative electrode 24. The separator 26 is a member that insulates the positive electrode 22 and the negative electrode 24. The configuration of the separator 26 may be the same as that of the prior art. The length Ls of the separator 26 in the long side direction Y is preferably the same as or longer than the length Ln of the negative electrode active material layer 24a in the long side direction Y. As the separator 26, for example, a porous sheet (micro-porous membrane) made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable. The separator 26 may be provided with a functional layer (for example, an adhesive layer or a heat-resistant layer) on the surface of the porous sheet.

[0036] The configuration of the non-aqueous electrolyte may be the same as that of the prior art. The non-aqueous electrolyte typically contains a non-aqueous solvent and a supporting salt (electrolyte salt). The non-aqueous solvent is, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The supporting salt is, for example, a fluorine-containing lithium salt such as lithium hexafluorophosphate (LiPF6) or lithium bis(fluorosulfonyl)imide (LiFSI). The non-aqueous electrolyte may further contain additives as necessary. The non-aqueous electrolyte is typically liquid, but may be gel-like. Further, in other embodiments, the power storage device 100 may be provided with a solid electrolyte instead of the non-aqueous electrolyte. In that case, the separator 26 can be omitted.

[0037] FIG. 6 is a plan view schematically showing the power storage module 500 and the cooling device 400. In FIG. 6, a detailed illustration of the upper surface of the power storage device 100 is omitted. As shown in FIG. 6, the cooling device 400 includes, here, an air inlet IP, an air outlet OP, an air-cooling fan 410, a temperature sensor 420, and a control device 430. The cooling device 400 is an air-cooled type cooling device that uses air as a refrigerant here. However, in other embodiments, the cooling device 400 may be a liquid-cooled type cooling device that uses a liquid refrigerant.

[0038] In this embodiment, the intake port IP is provided on one side (front F side) in the arrangement direction X of the power storage module 500. The exhaust port OP is provided on the other side (rear Rr side) in the arrangement direction X. The air-cooling fan 410 is attached to the intake port IP. The air-cooling fan 410 is configured to send wind (air) to the intake port IP. The configuration of the air-cooling fan 410 is not limited, but for example, it includes an electric motor (not shown). The temperature sensor 420 is arranged here at the central portion in the XY plane of the power storage module 500. The temperature sensor 420 is, for example, a thermocouple, a thermistor, or the like.

[0039] The control device 430 is electrically connected to the temperature sensor 420 and the electric motor of the air-cooling fan 410. When the control device 430 detects, for example, that the temperature inside the power storage module 500 has reached a predetermined first temperature or higher by the temperature sensor 420, it operates the air-cooling fan 410. As a result, low-temperature air outside the power storage module 500 is supplied into the power storage module 500 from the intake port IP, and an air flow AF is generated inside the power storage module 500. The supplied air passes through the inside of the power storage module 500 while cooling the power storage device 100, and is discharged from the exhaust port OP. When the control device 430 detects, for example, that the temperature inside the power storage module 500 has reached a predetermined second temperature or lower by the temperature sensor 420, it stops the air-cooling fan 460. According to such an air-cooled cooling device 400, the power storage device 100 can be cooled at low cost.

[0040] Incidentally, according to the study by the present inventors, inside a power storage module 500 equipped with a cooling mechanism such as a cooling device 400, for example, a temperature distribution occurs during charging and discharging of a plurality of power storage devices 100, and a low-temperature region A1 where the temperature becomes relatively low and a high-temperature region A2 where the temperature becomes relatively high may occur. Specifically, when the power storage device 100 generates heat due to charging and discharging, adjacent power storage devices 100 heat each other. As a result, in the central portion in the arrangement direction X, a chain reaction of heat generation occurs between the power storage devices 100, and the temperature tends to become relatively high. On the other hand, both ends in the arrangement direction X (the front F portion and the rear Rr portion in FIG. 6) have higher heat dissipation properties than the central portion, so chain reaction heat generation is less likely to occur. Therefore, at both ends in the arrangement direction X, the temperature tends to become relatively low.

[0041] Particularly in the present embodiment, an intake port IP through which a refrigerant (air) is supplied and an air-cooling fan 410 are arranged on the front F side in the arrangement direction X, and an exhaust port OP is arranged on the rear Rr side in the arrangement direction X. For this reason, both ends in the arrangement direction X tend to have a low temperature. Therefore, the central portion in the arrangement direction X becomes a high-temperature region A2 with a relatively high temperature, and both ends in the arrangement direction X (the front F portion and the rear Rr portion in FIG. 6) tend to become a low-temperature region A1 with a relatively low temperature. In particular, the front F portion in the arrangement direction X where the intake port IP and the air-cooling fan 410 are arranged is most likely to have the lowest temperature. That is, in the present embodiment, at least the front F side in the arrangement direction X tends to become a low-temperature region A1 with a relatively low temperature.

[0042] As described in Patent Document 1 and the like, if such a temperature distribution occurs in the power storage module 500, variations may occur in the high-rate tolerance of the power storage device 100. Specifically, the high-rate tolerance of the power storage device 100 may decrease in the low-temperature region A1. In this case, if the charge and discharge of the entire power storage module 500 are controlled based on the high-rate tolerance of the power storage device 100 in the low-temperature region A1, the high high-rate tolerance of the power storage device 100 in the high-temperature region A2 cannot be fully utilized. On the other hand, if the high-rate tolerance of the power storage device 100 in the high-temperature region A2 is used as a reference, a high voltage is applied to the power storage device 100 in the low-temperature region A1, and high-rate degradation is likely to accelerate. Thus, if a temperature distribution occurs in the power storage module 500, the high-rate tolerance of the entire power storage module 500 may decrease due to being pulled by the high-rate tolerance of the power storage device 100 in the low-temperature region A1. Furthermore, when the power storage module is mounted on a moving body such as a vehicle, there is also a possibility that the fuel efficiency will deteriorate.

[0043] Therefore, in the manufacturing method disclosed herein, the first power storage device 110 with high high-rate tolerance is arranged in the low-temperature region A1, and the second power storage device 120 with low high-rate tolerance is arranged in the high-temperature region A2. As a result, in the power storage module 500 after manufacturing, the high-rate tolerances of the plurality of power storage devices 100 can be leveled at a high level. Consequently, the acceleration of degradation can be suppressed, and the high-rate tolerance of the entire power storage module 500 can be improved. Hereinafter, a method for manufacturing such a power storage module with the high-rate tolerance leveled will be described.

[0044] [Method for manufacturing a power storage module] Next, a method for manufacturing the power storage module 500 including a plurality of power storage devices 100 will be described. The power storage module 500 can be manufactured, for example, by a manufacturing method including: (Process A) a preparation process of preparing a first power storage device 110 and a second power storage device 120; (Process B) a temperature distribution prediction process of predicting the temperature distribution within the power storage module 500; and (Process C) a construction process of constructing the power storage module 500 by combining the first power storage device 110 and the second power storage device 120. The manufacturing method disclosed herein may further include other processes at any stage. Note that the order of (Process A) the preparation process and (Process B) the temperature distribution prediction process is not particularly limited. For example, (Process B) the temperature distribution prediction process may be performed after (Process A) the preparation process, or (Process A) the preparation process may be performed after (Process B) the temperature distribution prediction process.

[0045] (In Process A) the preparation process, as the plurality of power storage devices 100, a first power storage device 110 having a first electrode body formed with a relatively low pressing pressure and a second power storage device having a second electrode body formed with a relatively high pressing pressure are prepared. In the present embodiment, (Process A) the preparation process includes, in this order: (A-1) an electrode body manufacturing process of manufacturing a flat-shaped electrode body; (A-2) a housing process of housing the electrode body 20 in the battery case 10; and (A-3) a conditioning process.

[0046] (A-1) In the electrode body manufacturing process, first, after forming a laminate by laminating a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 with a strip-shaped separator 26 interposed therebetween, the laminate is wound, thereby producing a cylindrical wound electrode body. Then, pressing is performed to crush the cylindrical wound electrode body with a predetermined pressing pressure. Thereby, a flat-shaped electrode body 20 can be formed. Here, in the manufacturing method according to the present embodiment, two types of electrode bodies 20 formed with different pressing pressures are produced. Specifically, in the present embodiment, a first electrode body 20X formed with a relatively low pressing pressure and a second electrode body 20Y formed with a relatively high pressing pressure are produced. In the experiment conducted by the present inventor, it has been confirmed that as the pressing pressure during the formation of the electrode body 20 decreases, the high-rate tolerance of the formed electrode body 20 improves.

[0047] Note that the pressing pressure of each electrode body 20 is appropriately adjusted according to the temperature distribution of the power storage module 500 described later, and is not intended to limit the technology disclosed herein. As an example, when the pressing pressure for the second electrode body 20Y is set to 100%, the pressing pressure for the first electrode body 20X is preferably 80% or less, more preferably 70% or less, and particularly preferably 50% or less. Thereby, the high-rate tolerance of the first electrode body 20X can be relatively improved compared to the second electrode body 20Y. Also, the lower limit value of the pressing pressure for the first electrode body 20X is not particularly limited and may be 1% or more, 5% or more, or 10% or more. However, considering the formability of the first electrode body 20X, etc., it is preferable to set the absolute value of the pressing pressure for the first electrode body 20X to a certain value or more. For example, the absolute value of the pressing pressure for the first electrode body 20X is preferably 0.1 kN / cm 2 or more, more preferably 0.15 kN / cm 2 or more, and particularly preferably 0.2 kN / cm 2 or more.

[0048] Also, the specific pressing pressure for the second electrode body 20Y is preferably 0.6 kN / cm 2 or more, more preferably 0.8 kN / cm 2 or more, and particularly preferably 1.0 kN / cm 2The above is particularly preferable. By this, each electrode body 20 can be appropriately formed. On the other hand, the upper limit value of the pressing pressure on the second electrode body 20Y is 3.0 kN / cm 2 or less is preferable, and 2.6 kN / cm 2 or less is more preferable, and 2.4 kN / cm 2 or less is particularly preferable. By this, the high-rate tolerance of each of the plurality of power storage devices 100 that construct the power storage module 500 can be leveled at a high level.

[0049] (A-2) In the accommodation step, the separately prepared electrode body 20 is accommodated in the battery case 10. In a preferred embodiment, first, the positive electrode tab group 23 of the electrode body 20 is joined to the positive electrode current collector 50, and the negative electrode tab group 25 of the electrode body 20 is joined to the negative electrode current collector 60. Thereby, the sealing plate 14 and the electrode body 20 are integrated. Next, the sealing plate 14 is placed over the opening 12h of the exterior body 12, and the electrode body 20 is disposed inside the exterior body 12. Next, the sealing plate 14 is welded to the periphery of the opening 12h of the exterior body 12 to integrate the exterior body 12 and the sealing plate 14. Next, the electrolytic solution is injected into the battery case 10 from the liquid injection hole 15 of the sealing plate 14. Thereby, a precursor (battery assembly) of the power storage device 100 is produced. Here, when producing the battery assembly of the first power storage device 110, the first electrode body 20X formed with a relatively low pressing pressure is used. On the other hand, when producing the battery assembly of the second power storage device 120, the second electrode body 20Y formed with a relatively high pressing pressure is used.

[0050] (A-3) In the conditioning step, the produced battery assembly is charged at least once. Preferably, the produced battery assembly is charged and discharged at least once. The charge and discharge of the battery assembly can be performed in the same manner as in the prior art. Typically, an external power source is connected between the positive electrode terminal 30 and the negative electrode terminal 40, and charging or discharging is performed until the terminals reach a predetermined state of charge (SOC). Then, the battery case 10 is hermetically sealed. As described above, the first power storage device 110 and the second power storage device 120 with different pressing pressures on the electrode body 20 can be prepared.

[0051] (Engineering B) In the temperature distribution prediction process, the temperature distribution within the power storage module 500 when a plurality of power storage devices 100 are charged and discharged is predicted. That is, for example, in the aspect as shown in FIG. 6, both end portions in the array direction X (particularly the front F portion in the array direction X) are likely to be low temperature regions A1. However, the temperature distribution within the power storage module 500 can also vary depending on the configuration of the cooling device 400 (for example, the intake port IP, the exhaust port OP, the installation position and number of the air cooling fans 410) and the heat dissipation path. Also, for example, the range (length in the array direction X) of the low temperature region A1 can also vary depending on, for example, the number of power storage devices 100 and the charge and discharge conditions. Therefore, it is preferable to predict the temperature distribution within the power storage module 500 during charge and discharge by means of preliminary experiments or simulations using commercially available analysis software. In particular, it is preferable to construct a power storage module for preliminary tests that mimics the power storage module 500, measure the temperature distribution, and predict the temperature distribution within the power storage module 500 based on the actual measurement.

[0052] In a preferred embodiment, first, a plurality of power storage devices for preliminary tests different from the first power storage device 110 and the second power storage device 120 manufactured in the preparation process are prepared, and temperature sensors are attached to each of them. Next, using the plurality of power storage devices for preliminary tests, a power storage module for preliminary tests that mimics the power storage module 500 is assembled. Next, the plurality of power storage devices for preliminary tests are actually charged and discharged (preferably at high rate charge and discharge), and the temperature distribution at this time is acquired. The charge and discharge conditions are preferably conditions assuming the actual usage mode. Then, based on the acquired temperature distribution, the temperature distribution within the power storage module 500 is predicted and divided, for example, into a low temperature region A1 and a high temperature region A2 (for example, divided into two parts).

[0053] (Project C) In the construction process, based on the temperature distribution predicted in the temperature distribution prediction process, the first power storage device 110 and the second power storage device 120 are arranged to construct the power storage module 500. Specifically, the first power storage device 110 having the first electrode body 20X with a relatively low press pressure during molding is arranged in the region separated from the low-temperature region A1, and the second power storage device 120 having the second electrode body 20Y with a relatively high press pressure during molding is arranged in the region separated from the high-temperature region A2. Then, for example, together with a plurality of spacers 200, the first power storage device 110 and the second power storage device 120 are constrained and integrally held by the constraint mechanism 300. In this way, the power storage module 500 can be constructed.

[0054] In the power storage module 500 constructed according to the above procedure, the first power storage device 110 with high high-rate resistance is arranged in the relatively low-temperature region A1 (both ends in the arrangement direction X). Also, the second power storage device 120 with low high-rate resistance is arranged in the relatively high-temperature region A2 (the central part in the arrangement direction X). Thereby, the high-rate resistances of the plurality of power storage devices 100 can be leveled at a high level. Also, different from the technology of Patent Document 1, since there is no need to be restricted by the framework of "cell group", the high-rate resistances of the plurality of power storage devices 100 can be flexibly adjusted according to the temperature distribution in the power storage module 500. Therefore, in some cases, the high-rate resistances of the plurality of power storage devices 100 can be leveled with higher accuracy compared to the technology of Patent Document 1. Furthermore, since the number of the constraint mechanisms 300 can be reduced compared to the technology of Patent Document 1, the volume energy density and fuel consumption can also be improved. In addition, the number of parts can be reduced and the manufacturing cost can be reduced.

[0055] In the power storage module 500 after manufacturing, the thickness of the flat portion 20a of the electrode body 20 is different between the first power storage device 110 and the second power storage device 120. Specifically, since the first electrode body 20X of the first power storage device 110 is molded at a relatively low pressing pressure, the flat portion 20a tends to be thick. On the other hand, since the second electrode body 20Y of the second power storage device 120 is molded at a relatively high pressing pressure, the flat portion 20a tends to be thin. For example, when the average thickness of the flat portion 20a of the second electrode body 20Y is taken as 100%, the average thickness of the first electrode body 20X can be 88% - 99% (preferably 89% - 97%, more preferably 90% - 96%). Here, the "average thickness of the first electrode body" is the average value of the thicknesses of the electrode bodies 20 of all the first power storage devices 110 included in the power storage module 500. Also, the "average thickness of the second electrode body" is the average value of the thicknesses of the electrode bodies 20 of all the second power storage devices 120 included in the power storage module 500.

[0056] In the power storage module 500 after manufacturing, the elasticity of the electrode body 20 may also be different between the first power storage device 110 and the second power storage device 120. Specifically, since the first electrode body 20X of the first power storage device 110 is molded at a relatively low pressing pressure, the elastic modulus tends to be high. On the other hand, since the second electrode body 20Y of the second power storage device 120 is molded at a relatively high pressing pressure, the elastic modulus tends to be low. For example, when the average elastic modulus of the second electrode body 20Y is taken as 100%, the average elastic modulus of the first electrode body 20X can be 3% - 95% (preferably 5% - 90%, more preferably 10% - 80%). Here, the "average elastic modulus of the first electrode body" is the average value of the elastic moduli (N / m 2 ) of the electrode bodies 20 of all the first power storage devices 110 included in the power storage module 500. Also, the "average elastic modulus of the second electrode body" is the average value of the elastic moduli (N / m 2 ) of the electrode bodies 20 of all the second power storage devices 120 included in the power storage module 500.

[0057] [Applications of the Power Storage Module] The power storage module 500 can be used for various applications. Since it has excellent high-rate resistance, it can be suitably used as a power source (driving power source) for motors mounted on applications that require high output, such as vehicles like passenger cars and trucks. The type of vehicle is not particularly limited, and examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), battery electric vehicles (BEVs), etc. By mounting the power storage module 500 on a moving body such as a vehicle, the fuel efficiency (electricity cost) of the moving body can be improved.

[0058] Hereinafter, several test examples related to the present invention will be described, but the present invention is not intended to be limited to such test examples.

[0059] In this test example, a plurality of power storage devices with different pressing pressures during electrode body forming were fabricated, and the high-rate resistance of each power storage device was confirmed. Specifically, as shown in Table 1, five types of wound electrode bodies with different pressing pressures during forming were fabricated. Then, each electrode body was housed in a battery case, and five types of power storage devices (lithium-ion secondary batteries, Examples 1 to 5) were fabricated. Note that the "pressing pressure during forming" in Table 1 is the ratio with the pressing pressure of Example 1 (1.0 kN / cm 2 ) taken as 1 (reference value). Also, the manufacturing conditions except for the pressing pressure during electrode body forming are common to all power storage devices. Next, the manufactured power storage device was adjusted to a state of SOC 50% in a temperature environment of 25°C, and a constant current discharge was performed at 150 A for 10 seconds, and the discharge resistance was measured. Next, the battery voltage drop ΔV that dropped in 10 seconds was read, and based on the battery voltage ΔV and the discharge current value (150 A), the IV resistance (initial resistance) was calculated.

[0060] Next, in a temperature environment of 25°C, the power storage device was adjusted to a state of SOC 50%, and after constant current charging was performed at a charging rate of 150 A for 10 seconds, it was paused for 5 seconds. Then, after constant current discharging was performed at a discharging rate of 10 A for 150 seconds, it was paused for 5 seconds. One cycle of such charge and discharge was repeated 1000 times to conduct a high-rate durability test. After the high-rate durability test, the IV resistance was measured in the same manner as the initial resistance, and the resistance increase rate was calculated from the ratio of the IV resistance after the durability test to the initial resistance (IV resistance after the durability test / initial resistance). The results are shown in Table 1. Note that Table 1 shows the relative values when the resistance increase rate of Example 1 is taken as 1.00 (reference).

[0061]

Table 1

[0062] As shown in Table 1, it was confirmed that as the press pressure during electrode body forming decreased, the resistance increase rate after the high-rate durability test decreased. From this, it was found that by adjusting the press pressure during electrode body forming, the high-rate tolerance of the power storage device after manufacturing can be controlled.

[0063] As described above, the preferred embodiments of the present invention have been explained, but the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the content disclosed in this specification and the common general knowledge in the art. The technology described in the claims includes various modifications and changes of the above-exemplified embodiments. For example, it is also possible to replace a part of the above-described embodiments with other modification examples, and it is also possible to add other modification examples to the above-described embodiments. Also, if its technical features are not described as essential, it is possible to appropriately delete them.

[0064] (1) For example, in the above-described embodiment, in the (Process A) preparation process, the pressing pressure when forming the electrode body 20 was intentionally made different. However, the embodiments of the present invention are not limited to this. For example, it is also possible to select and prepare the first power storage device 110 and the second power storage device 120 from among a large number of power storage devices in which the pressing pressure applied to the electrode body 20 varies, within a predetermined acceptable range.

[0065] As a specific example, when a used power storage device (which may be in the state of a power storage module) is recovered from the market and reused, that is, when the power storage device 100 is a reused product. In recent years, for example, power storage devices such as lithium-ion secondary batteries may be provided with identification information from the perspective of traceability and the like. In one example, an optical symbol readable by a reading device is attached to the surface of the power storage module (for example, the sealing plate 14). Alternatively, a small substrate containing identification information is mounted inside the power storage device or the like. The identification information may include, in addition to ID information such as model number, manufacturer name, country of manufacture, manufacturing factory name, and manufacturing date, material information such as the conditions (pressing pressure of the electrode body) during manufacturing.

[0066] In this case, the (Process A) preparation process may include: (1-a) an acquisition process of respectively reading the identification information attached to a large number of recovered power storage devices and obtaining information regarding the pressing pressure when forming the electrode body 20; and (1-b) based on the obtained information, extracting a plurality of power storage devices, and selecting, from among the plurality of extracted power storage devices, a first power storage device 110 having a relatively low pressing pressure of the electrode body 20 and a second power storage device 120 having a relatively high (low) pressing pressure of the electrode body 20. Such a method for manufacturing a power storage module can also be understood as a method for reusing a power storage device (reuse method). Note that in this specification, the "optical symbol" is a general term for information media that store information by a combination of portions with high and low optical reflectivities, and includes two-dimensional symbols (also referred to as two-dimensional codes, two-dimensional barcodes, etc.) such as QR codes (registered trademark), data matrices, and data tags.

[0067] (2) For example, in the embodiment of FIG. 6 described above, both end portions in the array direction X (the front F portion and the rear Rr portion in FIG. 6) are relatively low-temperature regions A1 with a low temperature, and the central portion in the array direction X is a relatively high-temperature region A2 with a high temperature. However, it is not limited to this. As described above, the temperature distribution within the power storage module 500 can vary depending on the configuration of the cooling device 400 (for example, the intake port IP, the exhaust port OP, the installation position and number of the air-cooling fans 410), the number of power storage devices 100, the charge / discharge conditions, and the like. Also, in the embodiment of FIG. 6 described above, the inside of the power storage module 500 is divided into two temperature regions, a low-temperature region A1 and a high-temperature region A2, and furthermore, the temperature distribution is symmetric with respect to the array direction X. However, it is not limited to this. For example, the inside of the power storage module 500 can also be divided into three or more temperature regions. In that case, in the embodiment of FIG. 6, the low-temperature region A1 on the rear Rr side in the array direction X may be set as a medium-temperature region A3 that is higher in temperature than the low-temperature region A1 and lower in temperature than the high-temperature region A2. Also, when the cooling path and the heat dissipation path are complex, the temperature distribution may be random, for example, the low-temperature region A1 and the high-temperature region A2 may appear alternately. Hereinafter, several specific modification examples will be described with reference to FIGS. 7 to 10. Note that in FIGS. 7 to 10, the illustration of the cooling device is omitted.

[0068] (First Modification Example) FIG. 7 is a plan view of a power storage module 500a according to the first modification example. As described above, it is known that chain heat generation is likely to occur between the power storage devices 100 at the central portion in the array direction X. Therefore, although not shown in FIG. 7, an intake port IP for supplying a refrigerant (air) and / or an air-cooling fan 410 may be additionally installed at the central portion in the array direction X, and the central portion may be strongly cooled. Then, as shown in FIG. 7, the temperature distribution of the power storage module 500a is, contrary to FIG. 6, such that the central portion in the array direction X becomes a relatively low-temperature region A1, and both end portions in the array direction X (the front F portion and the rear Rr portion in FIG. 7) may become relatively high-temperature regions A2.

[0069] In such a case or the like, as shown in FIG. 7, a first power storage device 110 having a first electrode body 20X with a relatively low pressing pressure (high high-rate resistance) is arranged at the center of the array direction X in the low-temperature region A1, and a second power storage device 120 having a second electrode body 20Y with a relatively high pressing pressure (low high-rate resistance) is arranged at both ends of the array direction X in the high-temperature region A2.

[0070] (Second and third modification examples) FIG. 8 is a plan view of a power storage module 500b according to the second modification example. FIG. 9 is a plan view of a power storage module 500c according to the third modification example. For example, when the air-cooling fan 410 installed on the front F side in the array direction X of FIG. 6 is powerful and has a high cooling capacity, as shown in FIGS. 8 and 9 respectively, the temperature distribution within the power storage modules 500b and 500c may be such that the front F portion in the array direction X becomes a low-temperature region A1 with a relatively low temperature, and the rear Rr portion in the array direction X becomes a high-temperature region A2 with a relatively high temperature.

[0071] In such a case or the like, as shown in FIGS. 8 and 9, a first power storage device 110 having a first electrode body 20X with a relatively low pressing pressure (high high-rate resistance) is arranged at the front F portion in the array direction X in the low-temperature region A1, and a second power storage device 120 having a second electrode body 20Y with a relatively high pressing pressure (low high-rate resistance) is arranged at the rear Rr portion in the array direction X in the high-temperature region A2.

[0072] Also, the distribution between the low-temperature region A1 and the high-temperature region A2 may vary depending on, for example, the number of power storage devices 100, charge-discharge conditions, etc. For this reason, the low-temperature region A1 and the high-temperature region A2 may be provided uniformly in the array direction X as shown in FIG. 8, or may be provided non-uniformly in the array direction X as shown in FIG. 9. In other words, the number of the first power storage devices 110 and the number of the second power storage devices 120 included in the power storage module 500 may be the same or different.

[0073] (Fourth Modification Example) FIG. 10 is a plan view of a power storage module 500d according to the fourth modification example. As shown in FIG. 10, the temperature distribution of the power storage module 500d is here divided in more detail than in FIG. 6. That is, both end portions in the array direction X (front F portion and rear Rr portion in FIG. 7) are low temperature regions A1 where the temperature is relatively low, the central portion in the array direction X is a high temperature region A2 where the temperature is relatively high, and between the low temperature region A1 and the high temperature region A2 is a medium temperature region A3 where the temperature is higher than that of the low temperature region A1 and lower than that of the high temperature region A2.

[0074] In such a case, as shown in FIG. 10, a first power storage device 110 having a first electrode body 20X with a relatively low pressing pressure (high high-rate resistance) is arranged at both end portions in the array direction X, which are the low temperature regions A1, and a second power storage device 120 having a second electrode body 20Y with a relatively high pressing pressure (low high-rate resistance) is arranged at the central portion in the array direction X, which is the high temperature region A2. Then, in the medium temperature region A3, which is intermediate between the low temperature region A1 and the high temperature region A2, a third power storage device 130 having a third electrode body 20Z formed at a pressure higher than that of the first electrode body 20X and lower than that of the second electrode body 20Y may be arranged. In other words, the plurality of power storage devices 100 may be arranged such that the pressing pressure during the formation of the electrode body 20 gradually decreases in the order of the high temperature region A2, the medium temperature region A3, and the low temperature region A1, here from the central portion in the array direction X toward both end portions.

[0075] Note that in FIG. 10, the inside of the power storage module 500 is divided into three temperature regions, but it is of course possible to divide it into four or more temperature regions. By thus finely dividing the inside of the power storage module 500 according to the temperature distribution, the effects of the technology disclosed herein can be exerted at a high level, and the high-rate resistance of the entire power storage module 500 can be improved better.

[0076] As described above, specific aspects of the technology disclosed herein include those described in the following items. Item 1: A method for manufacturing a power storage module including a plurality of power storage devices, wherein each of the plurality of power storage devices has a flat rectangular battery case and an electrode body accommodated in the battery case and having a flat portion facing the flat surface of the battery case. As the plurality of power storage devices, a first power storage device having a first electrode body formed with a relatively low pressing pressure and a second power storage device having a second electrode body formed with a relatively high pressing pressure are prepared. A preparation step, a temperature distribution prediction step of predicting the temperature distribution in the power storage module when the plurality of power storage devices are charged and discharged, and based on the temperature distribution, the first power storage device is arranged in a relatively low-temperature region and the second power storage device is arranged in a relatively high-temperature region to construct the power storage module. A method for manufacturing a power storage module including a construction step. Item 2: The method for manufacturing a power storage module according to Item 1, wherein when the pressing pressure for the second electrode body is 100%, the pressing pressure for the first electrode body is 10% to 80%. Item 3: The method for manufacturing a power storage module according to Item 1 or 2, wherein in the construction step, the first power storage device and the second power storage device are connected in series. Item 4: In the preparation step, a third power storage device having a third electrode body formed with a pressing pressure higher than that of the first electrode body and lower than that of the second electrode body is further prepared. In the construction step, based on the temperature distribution, the third power storage device is arranged in a medium-temperature region where the temperature is higher than that of the low-temperature region and lower than that of the high-temperature region. The method for manufacturing a power storage module according to any one of Items 1 to 3.

Explanation of Signs

[0077] 10 Battery case 20 Electrode body 22 Positive electrode 24 Negative electrode 100 Power storage device 110 First power storage device 120 Second power storage device 130 Third power storage device 300 Constraint mechanism 400 Cooling device 410 Air-cooling fan 500 Energy storage module A1 Low-temperature region A2 High-temperature region A3 Medium-temperature region

Claims

1. A method for manufacturing a power storage module including a plurality of power storage devices, Each of the plurality of power storage devices, A flat rectangular battery case, An electrode body accommodated in the battery case and having a flat portion facing the flat surface of the battery case, And having, As the plurality of power storage devices, a first power storage device having a first electrode body formed with a relatively low pressing pressure and a second power storage device having a second electrode body formed with a relatively high pressing pressure are prepared in a preparation step, A temperature distribution prediction step of predicting a temperature distribution in the power storage module when the plurality of power storage devices are charged and discharged, Based on the temperature distribution, the first power storage device is arranged in a relatively low-temperature region and the second power storage device is arranged in a relatively high-temperature region to construct the power storage module in a construction step, A method for manufacturing a power storage module including.

2. The method for manufacturing a power storage module according to claim 1, wherein when the pressing pressure on the second electrode body is 100%, the pressing pressure on the first electrode body is 10% to 80%.

3. The method for manufacturing a power storage module according to claim 1, wherein in the construction step, the first power storage device and the second power storage device are connected in series.

4. In the preparation step, a third power storage device having a third electrode body formed with a pressing pressure higher than that of the first electrode body and lower than that of the second electrode body is further prepared, The method for manufacturing a power storage module according to any one of claims 1 to 3, wherein in the construction step, based on the temperature distribution, the third power storage device is arranged in a medium-temperature region having a temperature higher than that of the low-temperature region and lower than that of the high-temperature region.

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