Energy storage module and inspection method for energy storage module

Abstract

This disclosure aims to provide an energy storage module that enables rapid sealing inspection. [Solution] An energy storage module 100 having a plurality of bipolar electrode stacks 110, a plurality of frame-shaped sealing portions 140, and an electrolyte injection connector 170, wherein the energy storage module 100 has a plurality of electrolyte chambers 150 formed by two bipolar electrode stacks 110 adjacent in the stacking direction and a frame-shaped sealing portion 140 between them, and each of the plurality of electrolyte chambers 150 has an electrolyte injection hole 151 formed in the frame-shaped sealing portion 140, and the plurality of electrolyte injection holes 151 are arranged in a specific positional relationship of multiple rows in the stacking direction and multiple columns in the planar direction.

Description

[Technical Field]

[0001] This disclosure relates to an energy storage module and a method for inspecting an energy storage module. [Background technology]

[0002] Bipolar batteries are attracting attention because multiple batteries can be connected in series without the need for busbars or current collector terminals. The multiple electrolyte chambers in a bipolar battery's energy storage module, into which the electrolyte is injected, need to be individually sealed to prevent electrolyte junctions between electrodes, and various methods for testing the sealing performance have been proposed.

[0003] Patent Document 1 discloses an inspection method for inspecting an energy storage module comprising an electrode stack in which electrodes are stacked, and a sealing body that surrounds the side surface of the electrode stack, forms a plurality of internal spaces between adjacent electrodes, and seals the internal spaces, the inspection method comprising: a first step of simultaneously changing the internal pressure of a first set of internal spaces that are odd-numbered or even-numbered from one end of the stacking direction among a plurality of internal spaces arranged along the stacking direction of the electrode stack; and a second step of detecting whether or not there has been a change in internal pressure for a second set of internal spaces whose internal pressure was not changed in the first step. Patent Document 1 states that according to the disclosure in Patent Document 1, it is possible to provide an inspection method for an energy storage module that can perform inspection of the sealing performance of internal spaces simply and quickly.

[0004] Patent Document 2 describes an inspection method for an energy storage module comprising: an electrode plate; a laminate in which a plurality of bipolar electrodes, each including a positive electrode provided on one side of the electrode plate and a negative electrode provided on the other side of the electrode plate, are stacked; and a frame that holds the edges of the electrode plate on the side surface of the laminate extending in the stacking direction of the bipolar electrodes, comprising: a preparation step of preparing the energy storage module; and an inspection step of inspecting the airtightness of the energy storage module, wherein the energy storage module prepared in the preparation step is provided with at least a first injection port and a second injection port for injecting electrolyte into the frame, the frame comprises a plurality of first resin parts that hold the edges of the electrode plate, and a second resin part provided around the first resin part when viewed from the stacking direction, and the first injection port is provided on one of the plurality of first resin parts The invention discloses an inspection method for a power storage module, which includes a first opening and a second opening provided in the second resin part, the first opening communicating with the internal space of the power storage module and the second opening, the second liquid injection port having a third opening provided in a first resin part different from the first opening among a plurality of first resin parts, and a fourth opening provided in a location in the second resin part different from the second opening, the third opening communicating with the internal space of the power storage module and the fourth opening, the space between the internal space of the power storage module communicating with the first liquid injection port and the space communicating with the second liquid injection port is sealed, and the inspection step involves inspecting the airtightness of the power storage module based on the change in the thickness of the power storage module due to the inflow of fluid into the first liquid injection port and the second liquid injection port. Patent Document 2 states that according to the disclosure in Patent Document 2, an inspection method for a power storage module that can easily inspect the airtightness of the power storage module can be provided.

[0005] Patent Document 3 describes a method for manufacturing an energy storage module comprising an electrode stack including a plurality of electrodes stacked in a first direction, and a sealing member surrounding the electrode stack when viewed from the first direction, wherein the plurality of electrodes include an electrode plate, a bipolar electrode having a positive electrode provided on one side of the electrode plate and a negative electrode provided on the other side of the electrode plate, and the sealing member comprises a first resin portion having a first communication hole that communicates with an internal space provided between adjacent electrodes, and a second resin portion having a second communication hole that communicates with the first communication hole, and the manufacturing method is as described above A method for manufacturing an energy storage module is disclosed, comprising: a first molding step of attaching a first insert mold having a first through-hole forming section for forming a first through-hole to a mold, and forming the first resin part by resin molding using the mold; and a second molding step of attaching a second insert mold having a second through-hole forming section for forming the second through-hole to the mold, and forming the second resin part by resin molding using the mold, wherein the second molding step involves inserting the second through-hole forming section into the first through-hole to a position where it does not penetrate the first through-hole, and performing resin molding of the second resin part. Patent Document 3 states that according to the disclosure in Patent Document 3, an energy storage module can be manufactured smoothly. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-035664 [Patent Document 2] Japanese Patent Publication No. 2018-170265 [Patent Document 3] Japanese Patent Publication No. 2020-145030 [Overview of the project] [Problems that the invention aims to solve]

[0007] In a power storage module of a bipolar battery, reduction of the man-hours for inspecting the sealing performance of an electrolytic solution chamber is required. As items of the sealing performance inspection, leak inspection between adjacent electrolytic solution chambers (inter-electrolytic solution chamber leak inspection) and leak inspection inside a liquid injection connector (liquid injection connector internal leak inspection) are cited.

[0008] According to Patent Document 1, reduction of the man-hours for the inter-electrolytic solution chamber leak inspection can be achieved, but reduction of the man-hours for the sealing performance inspection in which the liquid injection connector internal leak inspection is added to the inter-electrolytic solution chamber leak inspection is required.

[0009] Therefore, an object of the present disclosure is to provide a power storage module capable of quickly inspecting the sealing performance of an electrolytic solution chamber.

Means for Solving the Problem

[0010] The present disclosure achieves the above object by the following means. 〈Aspect 1〉 A power storage module having a plurality of bipolar electrode laminates, a plurality of frame-shaped sealing portions, and a liquid injection connector, the power storage module has a plurality of electrolytic solution chambers formed by two of the bipolar electrode laminates adjacent in the stacking direction and the frame-shaped sealing portion therebetween, the plurality of electrolytic solution chambers each have a liquid injection hole formed in the frame-shaped sealing portion, the plurality of liquid injection holes are integrally arranged in a positional relationship of a plurality of rows in the stacking direction and a plurality of columns in the plane direction, and each of the plurality of liquid injection holes communicates with a plurality of liquid injection channels of the liquid injection connector, Regarding the m-th and n-th electrolytic solution chambers counted from the lower layer side in the stacking direction, there is at least one set of combinations of m and n that satisfy the following relationship: (i) The liquid injection hole of the n-th electrolytic solution chamber is arranged adjacent to the upper side in the stacking direction of the liquid injection hole of the m-th electrolytic solution chamber, and (ii) when m is odd, n is even, and when m is even, n is odd, Power storage module. <Aspect 2> With respect to the p-th and q-th electrolyte chambers, counting from the bottom layer in the stacking direction of the bipolar electrode stack described above, there exists at least one combination of p and q that satisfies the following relationship: (i) The injection hole of the p-th electrolyte chamber is located adjacent to the left side in the plane direction of the injection hole of the q-th electrolyte chamber, and (ii) When p is odd, then q is even, and when p is even, then q is odd. The energy storage module described in Embodiment 1. <Aspect 3> The energy storage module according to embodiment 1 or 2, wherein the number of rows in the planar direction of the multiple liquid injection holes arranged in a cluster is even. <Aspect 4> The odd-numbered electrolyte chambers and even-numbered electrolyte chambers, counting from the bottom layer in the stacking direction of the bipolar electrode stack, are given different internal pressures, and To detect that gas or liquid from the even-numbered electrolyte chamber is flowing into one or more of the odd-numbered electrolyte chambers, and / or to detect that gas or liquid from the odd-numbered electrolyte chamber is flowing into one or more of the even-numbered electrolyte chambers. A method for inspecting an energy storage module according to any one of embodiments 1 to 3, including the method described above. <Aspect 5> The method for inspecting an energy storage module according to embodiment 4, wherein, upon detecting the aforementioned inflow, it is determined that there is an abnormality in the sealing between adjacent electrolyte chambers, the sealing between adjacent electrolyte injection channels of the electrolyte injection connector, and / or the sealing between the electrolyte injection connector and the frame-shaped sealing portion. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide an energy storage module that can quickly perform sealing inspections of the electrolyte chamber. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 is a schematic diagram illustrating the energy storage module of this disclosure. [Figure 2] Figure 2 is a schematic diagram illustrating the energy storage module of this disclosure. [Figure 3] Figure 3 is a schematic diagram illustrating the energy storage module of this disclosure. [Figure 4] Figure 4 is a schematic diagram illustrating the energy storage module of this disclosure. [Modes for carrying out the invention]

[0013] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below, and can be implemented in various ways within the scope of the gist of this disclosure. Furthermore, in the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] Energy storage module The energy storage module disclosed herein is A power storage module having multiple bipolar electrode stacks, multiple frame-shaped sealing portions, and a liquid injection connector, The above energy storage module has a plurality of electrolyte chambers formed by two bipolar electrode stacks adjacent to each other in the stacking direction and the frame-shaped sealing portion between them, Each of the above-mentioned multiple electrolyte chambers has an injection hole formed in the frame-shaped sealing portion, Multiple liquid injection holes are arranged in a configuration with multiple rows in the stacking direction and multiple columns in the planar direction, and each of the multiple liquid injection holes communicates with multiple liquid injection channels of the liquid injection connector. With respect to the m-th and nth electrolyte chambers counting from the bottom layer in the stacking direction, there exists at least one combination of m and n that satisfies the following relationship: (i) The injection hole of the nth electrolyte chamber is located adjacent to the upper side in the stacking direction of the injection hole of the mth electrolyte chamber, and (ii) When m is odd, n is even, and when m is even, n is odd.

[0015] According to this disclosure, it is possible to provide an energy storage module that can quickly perform sealing inspections of the electrolyte chamber.

[0016] In this specification, "sealing inspection" means an inspection to confirm that there is no leakage of electrolyte into other electrolyte chambers when the electrolyte chamber is filled with electrolyte. If leakage into other electrolyte chambers occurs, a liquid junction will occur, which can cause failure of the energy storage module. Examples of leakage into other electrolyte chambers include leakage between electrolyte chambers and leakage within the electrolyte injection connector.

[0017] When performing an electrolyte chamber leak test on an energy storage module, the test method described in Patent Document 1 makes it possible to perform the electrolyte chamber leak test in a single step.

[0018] On the other hand, if a leak inspection inside the electrolyte injection connector is performed in addition to the electrolyte chamber leak inspection using the inspection method of Patent Document 1, it may be necessary to add a separate step for the leak inspection inside the electrolyte injection connector.

[0019] In contrast, the present disclosers have found that if an energy storage module is such that the injection hole of the nth electrolyte chamber is located adjacent to the injection hole of the mth electrolyte chamber on the upper side in the stacking direction, and when m is odd, n is even, and when m is even, n is odd, then leakage testing between electrolyte chambers and leakage testing within the injection connector can be performed in a single step.

[0020] In this specification, "x-th electrolyte chamber" refers to the x-th cell, counting from the electrolyte chamber located at the bottom in the stacking direction. "x" is any natural number not exceeding the number of electrolyte chambers in the energy storage module.

[0021] In this specification, "stack direction" means the direction in which the bipolar electrode stacks are stacked. Furthermore, "lower side in the stack direction" means the side of the positive electrode terminal stack in the stack direction, and "upper side in the stack direction" means the side of the negative electrode terminal stack in the stack direction.

[0022] In this specification, “plane direction” means any direction in a plane perpendicular to the stacking direction. “Left side in plane direction” means the left side of the side of the energy storage module when viewed from the front, and “right side in plane direction” means the right side of the side of the energy storage module when viewed from the front.

[0023] The energy storage module of this disclosure comprises a plurality of bipolar electrode stacks, a plurality of frame-shaped sealing portions, and a liquid injection connector. The energy storage module may be applied to a lithium-ion secondary battery.

[0024] Figure 1 is a schematic diagram showing, but is not limited to, one embodiment of the energy storage module of the present disclosure.

[0025] For example, as shown in Figure 1, the energy storage module 100 has multiple bipolar electrode stacks 110 and multiple frame-shaped sealing portions 140, and is short in shape when viewed from the stacking direction.

[0026] The bipolar electrode laminate 110 is composed of a current collector layer 111, a positive electrode active material layer 112, and a negative electrode active material layer 113. The positive electrode active material layer 112 is laminated on one side of the current collector layer 111, and the negative electrode active material layer 113 is laminated on the opposite side of the same side. The positive electrode active material layer 112 of the bipolar electrode laminate 110 is adjacent to the negative electrode active material layer 113 with a separator 160 in between. In addition, the negative electrode active material layer 113 of one bipolar electrode laminate 110 is adjacent to the positive electrode active material layer 112 in the lamination direction with a separator 160 in between.

[0027] The energy storage module 100 has a negative electrode terminal stack 120 at one end in the stacking direction and a positive electrode terminal stack 130 at the opposite end. The negative electrode terminal stack 120 is composed of a current collector layer 111 and a negative electrode active material layer 113. The negative electrode active material layer 113 of the negative electrode terminal stack 120 is adjacent to the positive electrode active material layer 112 in the stacking direction, with a separator 160 in between. The positive electrode terminal stack 130 is composed of a current collector layer 111 and a positive electrode active material layer 112. The positive electrode active material layer 112 of the positive electrode terminal stack 130 is adjacent to the negative electrode active material layer 113 in the stacking direction, with a separator 160 in between.

[0028] The frame-shaped sealing portion 140 is arranged in a frame shape around the periphery of the current collector layer 111 of the bipolar electrode laminate 110, the negative electrode terminal laminate 120, and the positive electrode terminal laminate 130. A liquid injection connector 170 is attached to a part of the frame-shaped sealing portion.

[0029] <Frame-shaped sealing part> The frame-shaped sealing portion may be arranged in a frame shape on the periphery of the current collector layer of the bipolar electrode laminate. The frame-shaped sealing portion may be welded to the bipolar electrode laminate by ultrasonic waves or heat, and hermetically joined.

[0030] The material of the frame-shaped sealing portion is not particularly limited and may be, for example, a material having insulating and electrolyte-resistant properties. The material of the frame-shaped sealing portion may be, for example, a porous film such as polyethylene (PE) or polypropylene (PP), or a woven or nonwoven fabric made of polypropylene, methylcellulose, etc.

[0031] The dimensions of the frame-shaped sealing portion are not particularly limited and may be determined as appropriate based on the required strength of the energy storage module, the required sealing performance, etc.

[0032] <Fluid injection connector> The material of the fluid injection connector is not particularly limited and may be, for example, a material having insulating and electrolyte-resistant properties. The material of the fluid injection connector may be a resin, such as polyethylene (PE), polypropylene (PP), etc.

[0033] The dimensions of the fluid injection connector are not particularly limited and may be determined as appropriate based on, for example, the dimensions of the energy storage module, the dimensions of the fluid injection hole, etc. The fluid injection connector may be a single unit or it may be divided into parts.

[0034] The energy storage module of this disclosure has a plurality of electrolyte chambers formed by two bipolar electrode stacks adjacent to each other in the stacking direction and a frame-shaped sealing portion between them.

[0035] For example, as shown in Figure 1, the energy storage module 100 has multiple electrolyte chambers 150 formed by two bipolar electrode stacks 110 adjacent to each other in the stacking direction and a frame-shaped sealing portion 140. In other words, the energy storage module 100 can be said to be composed of multiple stacked electrolyte chambers 150. The electrolyte chambers 150 are partitioned by separators 160. The uppermost electrolyte chamber 150 is formed by a negative electrode terminal stack 120, a bipolar electrode stack 110 adjacent to the negative electrode terminal stack 120 in the stacking direction, and a frame-shaped sealing portion 140. The lowermost electrolyte chamber 150 is formed by a positive electrode terminal stack 130, a bipolar electrode stack 110 adjacent to the positive electrode terminal stack 130 in the stacking direction, and a frame-shaped sealing portion 140.

[0036] <Electrolyte chamber> Each electrolyte chamber has an injection hole formed in the sealing portion. The electrolyte chambers may be filled with electrolyte.

[0037] For example, as shown in Figure 1, each electrolyte chamber 150 has an injection hole 151 formed by the penetration of the sealing portion.

[0038] The shape of the injection hole is not particularly limited and may be, for example, short in shape. Furthermore, the injection hole may be sealed with a sealing material after the electrolyte has been filled.

[0039] Multiple liquid injection holes are arranged in a configuration with multiple rows in the stacking direction and multiple columns in the planar direction, and each of the multiple liquid injection holes communicates with multiple liquid injection channels of the liquid injection connector.

[0040] With respect to the m-th and n-th electrolyte chambers, counting from the bottom layer in the stacking direction, there exists at least one combination of m and n that satisfies the following relationship: (i) The injection hole of the nth electrolyte chamber is located adjacent to the injection hole of the mth electrolyte chamber on the upper side in the stacking direction, and (ii) When m is odd, n is even, and when m is even, n is odd.

[0041] Figure 2 is a schematic diagram of one embodiment of the energy storage module in this disclosure, but is not limited to this embodiment.

[0042] For example, as shown in Figure 2, the first to 30th electrolyte chambers 150 of the energy storage module 100 have injection holes 151 located in 10 different positions, from row A to row J, in the planar direction. For example, the first, twelfth, and 21st electrolyte chambers 150 have injection holes 151 at position A. These three injection holes 151 are connected to injection channels 171 provided in the injection connector 170, allowing electrolyte to be injected into the electrolyte chambers 150 via the injection channels 171. Similarly, the injection holes 151 at positions B to J are also connected to injection channels 171 provided in the injection connector 170.

[0043] In this specification, the positional relationship between each electrolyte chamber 150 and the injection holes 151 of each electrolyte chamber 150 in the energy storage module 100 is shown in a table as shown in Figure 4. Each cell corresponds to one injection hole 151. The number indicated in the cell indicates that it is the injection hole 151 of the electrolyte chamber 150 of the [number indicated in the cell]th cell. Furthermore, the first to third rows show the positional relationship of the injection holes 151 in the stacking direction, and columns A to J show the position of the injection holes 151 in the plane direction. For example, the energy storage module 100 in Figure 2 corresponds to Figure 4(a), where "1" in Figure 4(a) means that the injection hole 151 of the first electrolyte chamber 150 is located in column A, and the injection hole 151 of the first electrolyte chamber 150 located in the first row of column A is adjacent in the stacking direction to the injection hole 151 of the twelfth electrolyte chamber 150 located in the second row of the same column A. Note that there is a possibility of inter-electrolyte chamber leakage between two consecutive numbered electrolyte chambers 150, and there is a possibility of leakage within the injection connector between electrolyte chambers 150 that are adjacent in the stacking direction. For example, there is a possibility of inter-electrolyte chamber leakage between the electrolyte chambers 150 labeled "1" and "2" in Figure 4(a), and there is a possibility of leakage within the injection connector between "1" and "12".

[0044] Therefore, by simultaneously pressurizing the odd-numbered electrolyte chambers 150 and simultaneously detecting pressure fluctuations in the even-numbered electrolyte chambers 150, it is possible to perform leak testing between electrolyte chambers and leak testing within the electrolyte injection connector in a single process.

[0045] "Electrolyte chamber leakage," as shown in Figure 1, refers to the leakage of electrolyte between adjacent electrolyte chambers 150 when an abnormality such as a crack occurs in the bipolar electrode stack 110.

[0046] "Intra-electrolyte connector leak" refers to a potential leak that may occur in the intra-electrolyte connector 170 via the inside of the intra-electrolyte connector 170 when an abnormality such as a crack occurs in the intra-electrolyte connector 170, for example, between the 1st and 12th electrolyte chambers 150 where the intra-electrolyte holes 151 are adjacent in the stacking direction.

[0047] The positional relationship between each electrolyte chamber constituting the energy storage module and the injection holes of each electrolyte chamber only needs to be such that at least one combination of m and n exists, for example, the positional relationships shown in Figures 4(b) to (f). In the case of Figure 4(e), leak testing inside the injection connector is possible only between "1" and "12", between "12" and "21", between "2" and "11", and between "11" and "22".

[0048] On the other hand, in the case of a positional relationship like that shown in Figure 4(g), which corresponds to Figure 3, the above combination of m and n does not exist, and therefore it is not possible to perform both the electrolyte chamber leak test and the electrolyte injection connector leak test in a single process.

[0049] With respect to the p-th and q-th electrolyte chambers, counting from the bottom layer in the stacking direction of the bipolar electrode stack described above, there may be at least one combination of p and q that satisfies the following relationship: (i) The injection hole of the p-th electrolyte chamber is located adjacent to the left side in the plane direction of the injection hole of the q-th electrolyte chamber, and (ii) When p is odd, then q is even, and when p is even, then q is odd.

[0050] In addition to the above combinations of m and n, the existence of at least one combination of p and q allows for simultaneous pressurization of odd-numbered electrolyte chambers and simultaneous detection of pressure fluctuations in even-numbered electrolyte chambers. This enables simultaneous detection of leaks between electrolyte chambers and leaks within the injection connectors between adjacent electrolyte chambers in a single process. For example, in the positional relationships shown in Figures 4(a) to (f), at least one combination of p and q exists. In the case of Figure 4(d), leaks within the injection connectors between adjacent electrolyte chambers 150 in the row direction can only be inspected between "2" and "9", between "11" and "20", and between "22" and "29". Also, in the case of Figure 4(e), leaks within the injection connectors between adjacent electrolyte chambers 150 in the row direction can be inspected except between "11" and "13".

[0051] The number of rows in the planar direction of the multiple injection holes arranged in clusters may be even. If the number of rows is even, the positional relationship may be as shown in Figures 4(a) to (e), for example, and if the number of rows is odd, the positional relationship may be as shown in Figure 4(f). Also, as shown in Figure 4(f), the number of injection holes in each row does not have to be the same.

[0052] The number of rows in the stacking direction of the multiple injection holes arranged in a cluster is not particularly limited and may be, for example, three rows. Also, as shown in Figure 4(g), the number of injection holes in each row does not have to be the same.

[0053] The electrolyte chamber may be separated by a separator to prevent contact between the positive and negative electrodes.

[0054] (electrolyte) The electrolyte is not particularly limited and may, for example, contain lithium ions as carrier ions. The electrolyte may be, for example, a non-aqueous electrolyte. For example, a solution of lithium salt dissolved in a carbonate-based solvent at a predetermined concentration can be used as the electrolyte. Examples of carbonate-based solvents include fluoroethylene carbonate (FEC), ethylene carbonate (EC), and dimethyl carbonate (DMC). Examples of lithium salts include hexafluoride phosphate.

[0055] (Separator) The separator is not particularly limited and may be made of resins such as polyethylene (PE), polypropylene (PP), polyester, and polyamide. The separator may have a single-layer structure or a multi-layer structure. Examples of multi-layer separators include a two-layer PE / PP separator, or a three-layer PP / PE / PP or PE / PP / PE separator. The separator may also be made of a nonwoven fabric such as cellulose nonwoven fabric, resin nonwoven fabric, or glass fiber nonwoven fabric.

[0056] <Bipolar electrode stack> The bipolar electrode laminate may have a current collector layer, a positive electrode active material layer, and a negative electrode active material layer.

[0057] (Current collector layer) The material used for the negative electrode current collector layer is not particularly limited, but may be composed of metal foil, metal mesh, etc. Examples of materials used for the current collector layer include, but are not limited to, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, or carbon sheets. The current collector layer may have some kind of coating layer on its surface for purposes such as adjusting resistance.

[0058] The thickness of the current collector layer is not particularly limited, but may be 0.1 μm or more, or 1 μm or more, or 1 mm or less, or 100 μm or less.

[0059] (Cathode active material layer) The positive electrode active material layer contains at least positive electrode active material and may optionally contain a solid electrolyte, a conductive additive, and a binder. The positive electrode active material layer may also contain various other additives. The respective content of the positive electrode active material, solid electrolyte, conductive additive, binder, etc. in the positive electrode active material layer can be appropriately determined according to the desired battery performance. For example, if the total (total solid content) of the positive electrode active material layer is taken as 100% by mass, the content of the positive electrode active material may be 40% by mass or more, 50% by mass or more, 60% by mass or more, 100% by mass or less, or 90% by mass or less.

[0060] The material of the positive electrode active material is not particularly limited as long as it is capable of intercalating and releasing lithium ions. Examples of positive electrode active materials include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), and nickel-cobalt-manganese oxide (NCM:LiCO2). 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), lithium nickel-cobalt aluminum oxide (LiNi 0.8 (CoAl) 0.2 O2), Li 1+xMn 2-x-y M y It may be, but is not limited to, a heteroatom-substituted Li-Mn spinel or the like having a composition represented by O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn).

[0061] The positive electrode active material is not particularly limited, but may have a coating layer. The coating layer is a layer containing a substance that has lithium ion conduction performance, low reactivity with the positive electrode active material and the solid electrolyte, and can maintain the form of the coating layer that does not flow even when in contact with the active material and the solid electrolyte. Specific examples of the material constituting the coating layer include, in addition to LiNbO3, Li4Ti5O 12 , Li3PO4, etc., but are not limited thereto.

[0062] The shape of the positive electrode active material is not particularly limited as long as it is a general shape as the positive electrode active material of the battery. The positive electrode active material may be, for example, particulate. The positive electrode active material may be primary particles or secondary particles in which a plurality of primary particles are aggregated. The average particle diameter D 50 may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may also be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. The average particle diameter D 50 is the particle diameter (median diameter) at 50% of the integrated value in the volume-based particle size distribution determined by the laser diffraction / scattering method.

[0063] The material of the solid electrolyte is not particularly limited and may be, for example, a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte.

[0064] Examples of the sulfide solid electrolyte include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, or argyrodite-type solid electrolytes. Specific examples of the sulfide solid electrolyte include the Li2S-P2S5 system (Li7P3S 11, Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2 (Li 13 GeP3S 16 Li 10 GeP2S 12 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x Etc.; or combinations thereof, but not limited to these.

[0065] An example of an oxide solid electrolyte is Li7La3Zr2O 12 Li 7-x La3Zr 1-x Nb x O 12 Li 7-3x La3Zr2Al x O 12 Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+x Al x Ge 2-x (PO4)3, Li3PO4, or Li 3+x PO 4-x N x Examples include (LiPON), etc.; or combinations thereof, but are not limited to these.

[0066] The sulfide solid electrolyte and oxide solid electrolyte may be glass or crystallized glass (glass ceramics).

[0067] Examples of polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0068] The conductive additive is not particularly limited. Examples of conductive additives include, but are not limited to, vapor-grown carbon fibers (VGCF), acetylene black (AB), Ketjenblack (KB), carbon nanotubes (CNT), and carbon nanofibers (CNF). The conductive additive may be particulate or fibrous, and its size is not particularly limited. While the conductive additive is not particularly limited, it may be used alone or in combination of two or more types.

[0069] The binder is not particularly limited. The binder may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), etc., but is not limited to these. The binder is not particularly limited, and may be used alone or in combination of two or more types.

[0070] The shape of the positive electrode active material layer is not particularly limited, but may be, for example, a sheet-like positive electrode active material layer having a substantially flat surface. The thickness of the positive electrode active material layer is not particularly limited, but may be, for example, 0.1 μm or more, 1 μm or more, or 10 μm or more, or 2 mm or less, 1 mm or less, or 500 μm or less.

[0071] The positive electrode active material layer can be manufactured by applying known methods. For example, the positive electrode active material layer can be easily formed by dry or wet molding of a positive electrode mixture containing the above-mentioned components. The positive electrode active material layer may be formed together with the current collector layer, or it may be formed separately from the current collector layer.

[0072] (Negative electrode active material layer) As the negative electrode active material, various materials can be used whose potential for intercalating and releasing lithium ions (charge / discharge potential) is lower than that of the positive electrode active material described above. The material of the negative electrode active material is not particularly limited and may be metallic lithium, or any material capable of intercalating and releasing metallic ions such as lithium ions. Examples of materials capable of intercalating and releasing metallic ions such as lithium ions include alloy-based negative electrode active materials, carbon materials, or lithium titanate (Li4Ti5O4). 12 Examples include, but are not limited to, those listed above.

[0073] The alloy-based anode active material is not particularly limited and includes, for example, Si alloy-based anode active materials or Sn alloy-based anode active materials. Si alloy-based anode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, or solid solutions thereof. Si alloy-based anode active materials may also contain metallic elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. Sn alloy-based anode active materials include tin, tin oxide, tin nitride, or solid solutions thereof. Sn alloy-based anode active materials may also contain metallic elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc.

[0074] The carbon material is not particularly limited and examples include hard carbon, soft carbon, and graphite.

[0075] The shape of the negative electrode active material is not particularly limited, but any shape common for negative electrode active materials in batteries is acceptable. The negative electrode active material may be in the form of parts or sheets, for example.

[0076] The solid electrolyte, conductive additive, and binder that may be included in the negative electrode active material layer can be found by referring to the description of the positive electrode active material layer above.

[0077] The shape of the negative electrode active material layer is not particularly limited, but may be, for example, a sheet-like negative electrode active material layer having a substantially flat surface. The thickness of the negative electrode active material layer is not particularly limited, but may be, for example, 0.1 μm or more, 1 μm or more, or 10 μm or more, or 2 mm or less, 1 mm or less, or 500 μm or less.

[0078] The negative electrode active material layer can be manufactured by applying known methods. For example, the negative electrode active material layer can be easily formed by dry or wet molding of a negative electrode mixture containing the various components mentioned above. The negative electrode active material layer may be molded together with the negative electrode current collector layer, or it may be molded separately from the negative electrode current collector layer.

[0079] 《Inspection Method for Energy Storage Modules》 The inspection method for energy storage modules in this disclosure is: The odd-numbered electrolyte chambers and even-numbered electrolyte chambers, counting from the bottom layer in the stacking direction of the bipolar electrode stack, are given different internal pressures, and This includes detecting that gas or liquid from the even-numbered electrolyte chamber is flowing into one or more of the odd-numbered electrolyte chambers, and / or detecting that gas or liquid from the odd-numbered electrolyte chamber is flowing into one or more of the even-numbered electrolyte chambers.

[0080] According to this disclosure, it is possible to provide an inspection method that can quickly perform a sealing test on an electrolyte chamber.

[0081] In the following explanation, among the odd-numbered and even-numbered electrolyte chambers, the one with the higher internal pressure will be referred to as the first electrolyte chamber, and the one with the lower internal pressure will be referred to as the second electrolyte chamber. Therefore, the odd-numbered electrolyte chamber may be the first electrolyte chamber and the even-numbered electrolyte chamber may be the second electrolyte chamber, or vice versa.

[0082] The inspection method for the energy storage module of this disclosure includes setting the internal pressure of the odd-numbered electrolyte chambers and the even-numbered electrolyte chambers, counting from the lower layer side in the stacking direction of the bipolar electrode stack, to different levels.

[0083] The difference in internal pressure between the first electrolyte chamber and the second electrolyte chamber is preferably 10kPa or more, 20kPa or more, 30kPa or more, 40kPa or more, or 50kPa or more, from the viewpoint of detecting leakage between electrolyte chambers and / or leakage within the electrolyte injection connector. Alternatively, the difference in internal pressure may be 100kPa or less, 90kPa or less, 80kPa or less, 70kPa or less, or 60kPa or less. Furthermore, the internal pressures of the first and second electrolyte chambers are not particularly limited and may be appropriately determined considering the difference in internal pressure between the first and second electrolyte chambers, the pressure resistance performance of the energy storage module, the ambient pressure, etc.

[0084] The above-mentioned difference in internal pressure may be adjusted by adjusting the internal pressure of either the first electrolyte chamber or the second electrolyte chamber, or by adjusting both.

[0085] The internal pressure of the first and second electrolyte chambers may be adjusted by pressurization or by depressurization. The method of adjusting the internal pressure is not particularly limited. For example, the internal pressure of the electrolyte chambers may be adjusted by connecting a pump, compressor, etc., to the electrolyte injection connector and operating it. Furthermore, the method of adjusting the internal pressure is not limited to injecting or sucking air, but may also be done by injecting or sucking other gases or liquids. It is preferable to adjust the internal pressure of each first and second electrolyte chamber simultaneously from the viewpoint of streamlining the sealing performance test.

[0086] The inspection method for the energy storage module of this disclosure includes detecting that gas or liquid from the even-numbered electrolyte chambers is flowing into the odd-numbered one or more electrolyte chambers, and / or detecting that gas or liquid from the odd-numbered electrolyte chambers is flowing into the even-numbered one or more electrolyte chambers.

[0087] Because the internal pressure of the first electrolyte chamber is higher than that of the second electrolyte chamber, if a flow path exists between the first and second electrolyte chambers, gas or liquid from the first electrolyte chamber will flow into the second electrolyte chamber.

[0088] The liquid and gas are not particularly limited; for example, the liquid may be the electrolyte sealed inside when used as a bipolar battery, and the gas may be air, hydrogen, helium, or argon.

[0089] The method for detecting inflow is not particularly limited. For example, gas or liquid flowing into the second electrolyte chamber may be detected by connecting a detector to the liquid injection connector. If the expected inflowing substances are hydrogen, helium, or argon, they may be detected by a hydrogen leak detector, a helium leak detector, and an argon leak detector, respectively. Alternatively, detection may be performed by measuring the change in internal pressure of the first and / or second electrolyte chambers. The change in internal pressure may be detected by connecting a pressure sensor, pressure gauge, etc., to the liquid injection connector and sealing the electrolyte chamber to measure the internal pressure before and after the change in internal pressure.

[0090] If the above-mentioned inflow is detected, it may be determined that there is an abnormality in the sealing between adjacent electrolyte chambers, the sealing between adjacent electrolyte flow channels of the electrolyte connector, and / or the sealing between the electrolyte connector and the frame-shaped sealing portion.

[0091] If it is detected that gas or liquid from the first electrolyte chamber is flowing into one or more second electrolyte chambers, it may be determined that an electrolyte chamber leak is occurring between the second electrolyte chamber and the first electrolyte chamber adjacent to it in the stacking direction, and / or that an electrolyte connector leak is occurring between the second electrolyte chamber and the first electrolyte chamber whose injection hole is located adjacent to it in the stacking direction.

[0092] When detecting inflow using a detector, the detection threshold for determining an abnormality is not particularly limited and may be determined appropriately considering the internal pressure difference between the first and second electrolyte chambers, the type of gas or liquid flowing in, the detection limit of the detector, etc.

[0093] When detecting inflow by changes in internal pressure, the criteria for determining an abnormality based on the amount of change in internal pressure are not particularly limited and may be determined appropriately considering the internal pressure difference between the first and second electrolyte chambers, the inspection time, etc. For example, the amount of change in internal pressure may be 50 Pa or more, 100 Pa or more, or 200 Pa or more. The inspection time mentioned above refers to the time from adjusting the internal pressure in the first and second electrolyte chambers and sealing them until measuring the amount of change in internal pressure. The inspection time is not particularly limited and may be, for example, 50 seconds or more, 100 seconds or more, or 200 seconds or more. [Explanation of Symbols]

[0094] 100 Energy Storage Modules 110 Bipolar Electrode Stack 111 Current collector layer 112 Cathode active material layer 113 Negative electrode active material layer 120 Negative Electrode Termination Stack 130 Positive Terminal Stack 140 Frame-shaped sealing part 150 Electrolyte chamber 151 Liquid injection hole 160 Separator 170 Injection Connector 171 Injection channel

Claims

1. A power storage module having multiple bipolar electrode stacks, multiple frame-shaped sealing portions, and a liquid injection connector, The energy storage module has a plurality of electrolyte chambers formed by two bipolar electrode stacks adjacent to each other in the stacking direction and the frame-shaped sealing portion between them, Each of the plurality of electrolyte chambers has an injection hole formed in the frame-shaped sealing portion, Multiple liquid injection holes are arranged in a configuration with multiple rows in the stacking direction and multiple columns in the planar direction, and each of the multiple liquid injection holes communicates with multiple liquid injection channels of the liquid injection connector. With respect to the m-th and nth electrolyte chambers, counting from the bottom layer in the stacking direction, there exists at least one combination of m and n that satisfies the following relationship: (i) The injection hole of the nth electrolyte chamber is located adjacent to the injection hole of the mth electrolyte chamber on the upper side in the stacking direction, and (ii) When m is odd, n is even, and when m is even, n is odd. Energy storage module.

2. With respect to the p-th and q-th electrolyte chambers, counting from the bottom layer in the stacking direction of the bipolar electrode stack, there exists at least one pair of p and q that satisfies the following relationship: (i) The injection hole of the p-th electrolyte chamber is located adjacent to the left side in the plane direction of the injection hole of the q-th electrolyte chamber, and (ii) When p is odd, then q is even, and when p is even, then q is odd. The energy storage module according to claim 1.

3. The energy storage module according to claim 1 or 2, wherein the number of rows in the planar direction of the plurality of liquid injection holes arranged in a cluster is even.

4. The odd-numbered electrolyte chambers and even-numbered electrolyte chambers, counting from the lower layer in the stacking direction of the bipolar electrode stack, are given different internal pressures, and Detecting that gas or liquid from the even-numbered electrolyte chamber is flowing into the odd-numbered one or more electrolyte chambers, and / or detecting that gas or liquid from the odd-numbered electrolyte chamber is flowing into the even-numbered one or more electrolyte chambers. A method for inspecting an energy storage module according to claim 1 or 2, including the following:

5. The method for inspecting an energy storage module according to claim 4, wherein, upon detecting the aforementioned inflow, it is determined that there is an abnormality in the sealing between adjacent electrolyte chambers, the sealing between adjacent electrolyte flow paths of the electrolyte connector, and / or the sealing between the electrolyte connector and the frame-shaped sealing portion.

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