Energy storage module

Abstract

To provide a power storage module including a plurality of power storage devices which enable reduction of the number of components compared to a power storage device in which a positive electrode external terminal and a negative electrode external terminal are insulated from a case.SOLUTION: A power storage module 1 includes power storage device pairs 10 each having a first power storage device 100 having a first case 110 electrically connected to a negative electrode collector part 150d of an electrode body 150, and a positive electrode external terminal 160 connected to a positive electrode collector part 150c of the electrode body 150, and a second power storage device 200 having a second case 210 electrically connected to a positive electrode collector part 250c of an electrode body 250, and a negative electrode external terminal 270 connected to a negative electrode collector part 250d of the electrode body 250. In the power storage device pair 10, the first case 110 and the second case 210 are electrically connected to each other, and the first power storage device 100 and the second power storage device 200 are connected in series.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electricity storage module including a plurality of electricity storage devices, each having an electrode body housed in a conductive case. [Background technology]

[0002] Battery modules including a plurality of batteries, each having an electrode assembly housed in a conductive case, are known. Conventional battery modules use batteries in which the positive and negative external terminals are fixed to the case while being insulated from the case. For example, the positive external terminal of one battery is electrically connected to the negative external terminal of another adjacent battery via a separately prepared conductive connecting member such as a bus bar. Patent Document 1, for example, is cited as an example of related prior art (see Figures 1 and 2 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-10714 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned battery, the positive electrode external terminal and the negative electrode external terminal are each insulated from the case, and therefore an insulating member is required for each of the positive electrode external terminal and the negative electrode external terminal, resulting in a large number of parts.

[0005] The present invention has been made in consideration of the current situation, and provides an energy storage module including a plurality of energy storage devices that can reduce the number of parts compared to an energy storage device in which the positive and negative external terminals are each insulated from the case. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an electricity storage module including a plurality of electricity storage devices, each of which has a rectangular box-shaped conductive case and an electrode body housed in the case and including a positive electrode current collector and a negative electrode current collector, wherein the case is a first case that is conductive to the negative electrode current collector of the electrode body and has a negative electrode potential, the first electricity storage device being insulated from the first case and fixed to the first case, and having a positive electrode external terminal that connects to the positive electrode current collector of the electrode body within the first case; a second case in which a negative electrode terminal is electrically connected to the positive current collecting portion of the electrode body and set to a positive potential; a second power storage device insulated from the second case and fixed to the second case, the second power storage device having a negative external terminal connected to the negative current collecting portion of the electrode body within the second case; the first case and the second case are electrically connected to each other, and the first power storage device and the second power storage device of each power storage device pair are provided. ,product The power storage device pairs are stacked in the layer direction with an insulating member interposed therebetween to form a power storage module.

[0007] The above-mentioned power storage module is a power storage device pair having a first power storage device and a second power storage device. Duplicate Prepare a number. In the first electricity storage device, the first case is electrically connected to the negative electrode current collecting portion of the electrode body and also serves as the negative electrode external terminal, so no insulating member is required for the negative electrode, and therefore the number of parts can be reduced compared to electricity storage devices in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. In addition, in the second electricity storage device, the second case is electrically connected to the positive electrode current collecting portion of the electrode body and also serves as the positive electrode external terminal, so no insulating member is required for the positive electrode, which allows for a reduction in the number of parts compared to electricity storage devices in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. Furthermore, since the first case of the first electricity storage device and the second case of the second electricity storage device that make up the electricity storage device pair are electrically conductive, the first electricity storage device and the second electricity storage device can be connected with low resistance compared to connecting electrode external terminals fixed to the case while being insulated from the case. Furthermore, in the above-mentioned energy storage module, the first energy storage device and the second energy storage device that form each energy storage device pair are stacked in the stacking direction, and each energy storage device pair is stacked in the stacking direction via an insulating member, so that the energy storage device pairs can be insulated from each other while forming an energy storage module in which the first energy storage device and the second energy storage device that form each energy storage device pair are stacked.

[0008] Examples of the "electricity storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors. The first case of the first electricity storage device and the second case of the second electricity storage device that make up the electricity storage device pair may be connected, for example, by welding, brazing, soldering, etc., or by simply touching the cases together, or may be connected via a conductive connecting member such as a bus bar.

[0009] The first case and the negative electrode current collecting portion of the electrode assembly in the first electricity storage device may be connected by, for example, welding, brazing, soldering, or the like, or may be connected via a conductive connecting member. The second case and the positive electrode current collecting portion of the electrode body in the second electricity storage device may be connected by, for example, welding, brazing, soldering, or the like, or may be connected via a conductive connecting member. When the power storage module includes a plurality of pairs of power storage devices, the pairs of power storage devices may be connected in series or in parallel.

[0010] (2) In the power storage module according to (1), the pair of power storage devices includes the first case of the first power storage device and the second case of the second power storage device. directly It is preferable to use a welded electricity storage module.

[0011] In the above-described energy storage module, the first case of the first energy storage device and the second case of the second energy storage device that form the energy storage device pair are welded together, thereby achieving lower resistance than when the first case and the second case are simply in contact with each other.

[0012] (3) The storage battery according to (1) or (2) Module And, A coating layer made of insulating resin is formed on the entire inner surface of the first case, preventing the first case, which is at a negative electrode potential, from coming into contact with the electrolyte. It would be good to use it as a storage module.

[0014] Examples of the "insulating member" include an insulating spacer made of insulating resin or ceramic, an insulating film made of insulating resin film or heat-shrinkable film. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a partially cutaway cross-sectional view of a battery module according to the embodiment. [Figure 2] FIG. 2 is a top view of the battery module according to the embodiment. [Figure 3] FIG. 2 is a perspective view of a first battery according to the embodiment. [Figure 4] 3 is a partially cutaway cross-sectional view along the case height direction and the case width direction of the first battery according to the embodiment. FIG. [Figure 5] 5 is a cross-sectional view taken along the arrow BB in FIG. 4, along the case width direction and case thickness direction of the first battery according to the embodiment. [Figure 6] FIG. 2 is a perspective view of a second battery according to the embodiment. [Figure 7] 3 is a partially cutaway cross-sectional view along the case height direction and the case width direction of the second battery according to the embodiment. FIG. [Figure 8] 8 is a cross-sectional view taken along the arrow BB in FIG. 7, along the case width direction and case thickness direction of the second battery according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a partially cutaway cross-sectional view of a battery module (power storage module) 1 according to this embodiment, and Fig. 2 shows a top view of the battery module 1. Fig. 3 shows a perspective view of a first battery (first power storage device) 100, and Figs. 4 and 5 show cross-sectional views of the first battery 100. Fig. 6 shows a perspective view of a second battery (second power storage device) 200, and Figs. 7 and 8 show cross-sectional views of the second battery 200. In the following description, the case height direction AH, case width direction BH, and case thickness direction CH of the first battery 100 and the second battery 200 will be defined as the directions shown in Figs. 1 to 8.

[0017] The battery module 1 is mounted on vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. The battery module 1 includes a plurality of battery pairs (power storage device pairs) 10, each consisting of a first battery 100 and a second battery 200. The first battery 100 and the second battery 200 are each a prismatic (rectangular) sealed lithium ion secondary battery.

[0018] First, the first battery 100 will be described (see FIGS. 3 to 5). The first battery 100 is composed of a first case (case) 110 at a negative electrode potential, a rectangular parallelepiped, laminated electrode assembly 150 housed in the first case 110, and a positive electrode external terminal 160 supported in an insulated manner by the first case 110. The electrode assembly 150 is covered in a bag-shaped insulating holder (not shown) made of insulating film within the first case 110. An electrolyte 103 is also housed within the first case 110, a portion of which is impregnated into the electrode assembly 150 and the remainder of which is collected on a second side wall 114, which is the bottom wall of the first case 110.

[0019] The first case 110 is made of metal (aluminum in this embodiment). The first case 110 has a rectangular box shape and includes a first main wall portion 111, a second main wall portion 112, and four side walls 113 to 116 (the first side wall portion 113, the second side wall portion 114, the third side wall portion 115, and the fourth side wall portion 116), each of which has a rectangular shape. A coating layer 119 made of an insulating resin is formed over the entire inner surface of the first case 110. This coating layer 119 prevents the first case 110, which is at a negative electrode potential, from coming into contact with the electrolyte 103, thereby preventing the first case 110 from reacting with Li contained in the electrolyte 103 to form an alloy.

[0020] The first main wall portion 111 and the second main wall portion 112 have a larger area than the side wall portions 113 to 116. The first main wall portion 111 and the second main wall portion 112 face each other, with the first main wall portion 111 located on one side CH1 in the case thickness direction CH (the front right side in FIG. 3, the upper side in FIG. 5), and the second main wall portion 112 located on the other side CH2 in the case thickness direction CH (the rear left side in FIG. 3, the lower side in FIG. 5). Meanwhile, the side walls 113-116 each extend in the case thickness direction CH, connecting the first main wall 111 and the second main wall 112. The first side wall 113 and the second side wall 114 face each other, with the first side wall 113 located on an upper side AH1 in the case height direction AH and the second side wall 114 located on a lower side AH2 in the case height direction AH. The third side wall 115 and the fourth side wall 116 face each other, with the third side wall 115 located on one side BH1 in the case width direction BH and the fourth side wall 116 located on the other side BH2 in the case width direction BH.

[0021] The first case 110 is configured from a case body member 121 in the shape of a bottomed square cylinder having a rectangular opening 121c and accommodating an electrode assembly 150 therein, and a rectangular plate-shaped lid member 131 that closes the opening 121c of the case body member 121. Of these, the case body member 121 forms the second main wall portion 112 and four side wall portions 113 to 116. On the other hand, the lid member 131 forms the first main wall portion 111, and a lid peripheral portion 131f of the lid member 131 and an opening peripheral portion 121f of the opening 121c of the case body member 121 are airtightly joined (welded in this embodiment) around the entire periphery.

[0022] A safety valve 117 that breaks and opens when the internal pressure of the first case 110 exceeds a valve opening pressure is provided on the first side wall 113, which also serves as the upper wall of the first case 110. The first side wall 113 is also provided with a liquid injection hole 113k that penetrates the first side wall 113, and is airtightly sealed with a disk-shaped sealing member 118 made of aluminum. Furthermore, the negative electrode current collecting portion 150d of the electrode body 150 is connected to and electrically connected to the first side wall portion 113 within the first case 110. Therefore, the first case 110 of the first battery 100 is at a negative electrode potential.

[0023] Furthermore, a positive external terminal 160 is fixed to the first side wall portion 113 in a central portion in the case width direction BH of the first side wall portion 113 while being insulated from the first side wall portion 113. Specifically, an insertion hole 113h penetrating the first side wall portion 113 is provided in the central portion in the case width direction BH of the first side wall portion 113, and the positive external terminal 160 is inserted into this insertion hole 113h and extends from the inside of the first case 110 to the outside of the first case 110.

[0024] The positive electrode external terminal 160 is composed of a rectangular plate-shaped external terminal member 161 located on the outside (upper side AH1) of the first side wall portion 113, and an internal terminal member 162 located mainly on the inside (lower side AH2) of the first side wall portion 113 and in the insertion hole 113h. The external terminal member 161 and the internal terminal member 162 are made of aluminum. The internal terminal member 162 is connected to and electrically conductive with a positive electrode current collecting portion 150c of the electrode body 150, which will be described later, and extends from the inside of the first side wall portion 113 to the outside of the first side wall portion 113 through the insertion hole 113h, and further penetrates the external terminal member 161 to be connected to the external terminal member 161 by crimping. The positive external terminal 160 and the first side wall portion 113 are insulated from each other via an insulating portion 165. The insulating portion 165 is made of insulating resin and includes an external resin member 166 located on the outside of the first side wall portion 113 and in the insertion hole 113h, and an internal resin member 167 located on the inside of the first side wall portion 113.

[0025] Next, the electrode assembly 150 will be described. The electrode assembly 150 is formed by alternately stacking multiple positive electrode plates 151 and multiple negative electrode plates 154 in the case thickness direction CH with separators 157 made of porous resin films interposed between them. The positive electrode plates 151, negative electrode plates 154, and separators 157 each have a rectangular shape extending in the case height direction AH and the case width direction BH. Each positive electrode plate 151 has a positive electrode foil exposed portion 151r extending to the upper side AH1 at the center in the case width direction BH, and the positive electrode foil exposed portions 151r overlap each other in the thickness direction to form a positive electrode current collector 150c. This positive electrode current collector 150c is connected to an internal terminal member 162 of a positive electrode external terminal 160 by welding for electrical continuity. Each negative electrode plate 154 has a negative electrode foil exposed portion 154r extending toward the upper side AH1 near an end portion on the other side BH2 in the case width direction BH, and the negative electrode foil exposed portions 154r overlap each other in the thickness direction to form a negative electrode current collector 150d. This negative electrode current collector 150d is connected to the first side wall 113 inside the first case 110 by welding and is electrically connected.

[0026] The positive electrode plate 151 comprises a positive electrode current collector foil made of aluminum foil and positive electrode active material layers formed on both main surfaces of the positive electrode current collector foil. The positive electrode active material layers contain positive electrode active material particles capable of absorbing and releasing lithium ions. As described above, a portion of the positive electrode current collector foil extends to the upper side AH1 at the center in the case width direction BH, and both surfaces of the positive electrode current collector foil are exposed and free of the positive electrode active material layer, forming a positive electrode foil exposed portion 151r. The negative electrode plate 154 comprises a negative electrode current collector foil made of copper foil and negative electrode active material layers formed on both main surfaces of the negative electrode current collector foil. The negative electrode active material layers contain negative electrode active material particles capable of absorbing and releasing lithium ions. As described above, a portion of the negative electrode current collector foil extends to the upper side AH1 near the end of the other side BH2 in the case width direction BH, and both sides of the negative electrode current collector foil are exposed and free of the negative electrode active material layers, forming negative electrode foil exposed portions 154r.

[0027] Next, the second battery 200 will be described (see FIGS. 6 to 8). Descriptions of parts similar to those of the first battery 100 will be omitted or simplified. The second battery 200 is composed of a second case (case) 210 at a positive electrode potential, a rectangular parallelepiped laminated electrode assembly 250 housed in the second case 210, a negative electrode external terminal 270 supported by the second case 210 while being insulated from it, and the like.

[0028] The second case 210 has the same shape as the first case 110 of the first battery 100. That is, the second case 210 is a rectangular parallelepiped box having a first main wall portion 111, a second main wall portion 112, and four side wall portions 113 to 116, and is composed of a case body member 121 in the shape of a bottomed square cylinder and a rectangular plate-like cover member 131. However, no coating layer is formed on the inner surface of this second case 210.

[0029] The positive electrode current collecting portion 250c of the electrode body 250 is connected and electrically connected to the first side wall portion 113 of the second case 210 within the second case 210. Therefore, the second case 210 of the second battery 200 is at a positive electrode potential. In the second battery 200, a negative external terminal 270 is fixed to the first side wall portion 113 in the center of the first side wall portion 113 in the case width direction BH while being insulated from the first side wall portion 113. Specifically, the negative external terminal 270 is inserted into an insertion hole 113h provided in the first side wall portion 113, and extends from the inside of the second case 210 to the outside of the second case 210. The negative electrode external terminal 270 has a similar configuration to the positive electrode external terminal 160 of the first battery 100, and is composed of an external terminal member 271 and an internal terminal member 272. The external terminal member 271 and the internal terminal member 272 of the negative electrode external terminal 270 are made of copper. The negative electrode external terminal 270 and the first side wall portion 113 are insulated from each other via an insulating portion 165 made of an external resin member 166 and an internal resin member 167.

[0030] The electrode body 250 is similar to the electrode body 150 of the first battery 100 except that the shapes of the positive electrode current collector 250c and the negative electrode current collector 250d are different from those of the positive electrode current collector 150c and the negative electrode current collector 150d of the electrode body 150 of the first battery 100. The positive electrode current collecting portion 250c of the electrode body 250 is provided near the end portion on the other side BH2 in the case width direction BH. This positive electrode current collecting portion 250c is formed by overlapping the positive electrode foil exposed portions 251r of the positive electrode plates 251 that extend to the upper side AH1 in the thickness direction, and is connected to the first side wall portion 113 of the second case 210 by welding within the second case 210 for electrical continuity. On the other hand, the negative electrode current collecting portion 250d of the electrode body 250 is provided in the center in the case width direction BH. This negative electrode current collecting portion 250d is formed by overlapping the negative electrode foil exposed portions 254r of the negative electrode plates 254 that extend to the upper side AH1 in the thickness direction, and is connected to and electrically connected to the internal terminal member 272 of the negative electrode external terminal 270 by welding.

[0031] Next, the battery module 1 will be described (see FIGS. 1 and 2). The battery module 1 includes a plurality of battery pairs 10, insulating spacers (insulating members) 20 interposed between adjacent battery pairs 10, and a module case 40 that houses these. Each battery pair 10 is composed of the first battery 100 and the second battery 200 described above, and the first case 110 of the first battery 100 and the second case 210 of the second battery 200 are welded together.

[0032] Specifically, the first battery 100 and the second battery 200 are stacked in the case thickness direction CH (stacking direction SH) so that the first main wall portion 111 of the first case 110 of the first battery 100 faces the second main wall portion 112 of the second case 210 of the second battery 200, and the peripheral edge portion 111s of the first main wall portion 111 of the first battery 100 and the peripheral edge portion 112s of the second main wall portion 112 of the second battery 200 are welded along their entire periphery. This establishes electrical continuity between the first case 110, which is set to the negative electrode potential of the first battery 100, and the second case 210, which is set to the positive electrode potential of the second battery 200, and the first battery 100 and the second battery 200 are connected in series.

[0033] The battery module 1 includes a plurality of battery pairs 10, which are stacked in the stacking direction SH via rectangular plate-shaped insulating spacers 20 made of insulating resin. As a result, in the battery module 1 of this embodiment, all of the first batteries 100 and second batteries 200 are stacked in the stacking direction SH. The positive external terminal 160 of the first battery 100 and the negative external terminal 270 of the second battery 200 of a battery pair 10 adjacent to each other in the stacking direction SH with the insulating spacer 20 interposed therebetween are electrically connected via a rectangular plate-shaped bus bar (conductive connecting member) 30 extending in the stacking direction SH. The bus bar 30 and the positive external terminal 160 or the negative external terminal 270 are connected by welding, respectively. The module case 40 is made of resin and has a rectangular cylindrical shape with a bottom and a rectangular opening 40c.

[0034] The battery module 1 of this embodiment includes a plurality of battery pairs 10 each having a first battery 100 and a second battery 200 as described above. In each first battery 100, the first case 110 is electrically connected to the negative electrode current collecting portion 150d of the electrode body 150 and also serves as the negative electrode external terminal, so no insulating member is required for the negative electrode. This allows for a reduction in the number of parts compared to a battery (not shown) in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. Furthermore, in each second battery 200, the second case 210 is electrically connected to the positive electrode current collecting portion 250c of the electrode body 250 and also serves as the positive electrode external terminal, so no insulating member is required for the positive electrode. This allows for a reduction in the number of parts compared to a battery (not shown) in which the positive electrode external terminal and the negative electrode external terminal are each insulated from the case. Furthermore, since the first case 110 of the first battery 100 and the second case 210 of the second battery 200 that make up the battery pair 10 are electrically conductive, the first battery 100 and the second battery 200 can be connected with low resistance compared to connecting electrode external terminals fixed to the case while being insulated from the case.

[0035] Furthermore, in this embodiment, the first case 110 of the first battery 100 and the second case 210 of the second battery 200 of each battery pair 10 are welded together, which results in lower resistance than when the first case 110 and the second case 210 are simply in contact with each other. In this embodiment, the first battery 100 and the second battery 200 that make up each battery pair 10 are stacked in the stacking direction SH, and each battery pair 10 is stacked in the stacking direction SH via an insulating spacer 20. Therefore, a battery module 1 can be formed in which the first battery 100 and the second battery 200 that make up each battery pair 10 are stacked while insulating the battery pairs 10 from each other.

[0036] Next, a method for manufacturing the first battery 100, the second battery 200, and the battery module 1 including these will be described. For the first battery 100, a case body member 121 is prepared, and a positive external terminal 160 is fixed to a first side wall portion 113 of this case body member 121. The electrode body 150 is also formed, and the electrode body 150 is wrapped in a bag-shaped insulating holder (not shown). Then, the positive current collector 150c of the electrode body 150 is laser-welded to the internal terminal member 162 of the positive external terminal 160 fixed to the case body member 121, and the negative current collector 150d of the electrode body 150 is laser-welded to the first side wall portion 113 of the case body member 121. The electrode body 150 is then housed within the case body member 121.

[0037] Next, lid member 131 is placed on case body member 121, and lid peripheral portion 131f of lid member 131 is brought into contact with opening peripheral portion 121f of case body member 121 over the entire periphery. Then, lid peripheral portion 131f and opening peripheral portion 121f are laser-welded over the entire periphery to form case 110. Next, electrolyte 103 is poured into case 110 through pouring hole 113k, and electrolyte 103 is impregnated into electrode body 150. Thereafter, pouring hole 113k is covered from the outside with sealing member 118, and sealing member 118 is welded to case 110 by laser.

[0038] Next, a charging device (not shown) is connected to this first battery 100, and the first battery 100 is initially charged. After that, the initially charged first battery 100 is left to stand for a predetermined time to age the first battery 100. In this way, the first battery 100 is completed. The second battery 200 is manufactured in the same manner as the first battery 100, except that the relationship between the positive electrode and the negative electrode is different.

[0039] Next, the first battery 100 and the second battery 200 are stacked in the case thickness direction CH (stacking direction SH) so that the first main wall portion 111 of the first case 110 of the first battery 100 faces the second main wall portion 112 of the second case 210 of the second battery 200. Then, a laser beam is irradiated along the entire periphery of the boundary between the peripheral edge portion 111s of the first main wall portion 111 of the first battery 100 and the peripheral edge portion 112s of the second main wall portion 112 of the second battery 200, to laser-weld the first main wall portion 111 of the first battery 100 and the second main wall portion 112 of the second battery 200.

[0040] Next, insulating spacers 20 are prepared, and multiple battery pairs 10 are stacked in the stacking direction SH with the insulating spacers 20 between them, and these are housed in a module case 40. After that, the positive electrode external terminals 160 and negative electrode external terminals 270 of adjacent battery pairs 10 with the insulating spacers 20 interposed therebetween are connected via bus bars 30, respectively. The bus bars 30 are laser welded to the positive electrode external terminals 160 or negative electrode external terminals 270. In this way, the battery module 1 is completed.

[0041] Although the present invention has been described above in accordance with the embodiments, it goes without saying that the present invention is not limited to the embodiments and can be modified and applied as appropriate within the scope of the invention. For example, in the embodiment, the insulating spacer 20 made of insulating resin is used as the "insulating member" that insulates the battery pairs 10 from each other, but the insulating member is not limited to this. An insulating film made of an insulating heat-shrinkable film can also be used as the insulating member. Specifically, after the first battery 100 and the second battery 200 are welded to form the battery pair 10, the battery pair 10 is covered with an insulating film made of heat-shrinkable film, except for the vicinity of the positive electrode external terminal 160 and the negative electrode external terminal 270. Then, multiple battery pairs 10 covered with the insulating film are stacked in the stacking direction SH and housed in a module case. [Explanation of symbols]

[0042] 1 Battery module (energy storage module) 10 Battery pair (power storage device pair) 20 Insulating spacer (insulating member) 30 Bus bar (conductive connecting member) 100 first battery (first power storage device) 200 Second battery (second power storage device) 110 Case 1 (Case) 210 Second Case (Case) 150,250 Electrode body 150c, 250c Positive electrode current collector 150d, 250d Negative electrode current collector 160 Positive external terminal 270 Negative external terminal 165 Insulation section SH stacking direction

Claims

1. An electricity storage module including a plurality of electricity storage devices, each of which has a rectangular box-shaped conductive case and an electrode body housed in the case and including a positive electrode current collector and a negative electrode current collector, a first electricity storage device, the case being a first case that is electrically connected to the negative electrode current collecting portion of the electrode body and has a negative electrode potential, the first electricity storage device being insulated from the first case and fixed to the first case, and having a positive electrode external terminal that is connected to the positive electrode current collecting portion of the electrode body within the first case; the case is a second case that is electrically connected to the positive current collecting portion of the electrode body and has a positive electrode potential, the second electricity storage device is insulated from the second case, is fixed to the second case, and has a negative external terminal that is connected to the negative current collecting portion of the electrode body within the second case, The first case and the second case are electrically connected, and the first power storage device and the second power storage device are connected in series. The power storage device includes a plurality of pairs of power storage devices, the first power storage device and the second power storage device forming each of the power storage device pairs are stacked in a stacking direction, Each of the power storage device pairs is stacked in the stacking direction via an insulating member. Energy storage module.

2. The energy storage module according to claim 1, The power storage device pair includes: The first case of the first power storage device and the second case of the second power storage device are directly welded together. Energy storage module.

3. The energy storage module according to claim 1 or 2, A coating layer made of insulating resin is formed on the entire inner surface of the first case, preventing the first case, which is at a negative electrode potential, from coming into contact with the electrolyte. Energy storage module.

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