Energy Storage Module

Abstract

To provide a power storage module with which it is possible to suppress a further rise of temperature at an early stage.SOLUTION: A power storage module based on the present disclosure comprises a pair of electrode plates 10a, 10b, a sealing member 20a, a battery element 30a, and an insulating member 40a. The sealing member 20a is provided between the pair of electrode plates 10a, 10b in order to form a space S1 together with the pair of electrode plates 10a, 10b. The battery element 30a includes a cathode active material layer and an anode active material layer. The cathode active material layer is provided on the top face of one electrode plate 10a in the space S1. The anode active material layer is provided on the top face of the other electrode plate 10b in the space S1. The insulating member 40a is located between the pair of electrode plates 10a, 10b on the side opposite the space S1, as seen from the sealing member 20a. The melting point of the insulating member 40a is lower than the melting point of the sealing member 20a.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] JP 2022-081868 A (Patent Document 1) discloses a conventional electricity storage module. In the electricity storage module, a spacer prevents a short circuit caused by contact between a positive electrode current collector and a negative electrode current collector. The spacer is in the shape of a frame surrounding the periphery of the positive electrode active material layer and the negative electrode active material layer. The spacer seals the sealed space together with the positive electrode current collector and the negative electrode current collector, and suppresses leakage of the electrolyte contained in the sealed space to the outside of the sealed space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-081868 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for an electricity storage module that can quickly suppress a further increase in temperature when excessive heat is generated in the electricity storage module.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an energy storage module that can quickly suppress a further increase in temperature. [Means for solving the problem]

[0006] The energy storage module according to the present disclosure includes a pair of electrode plates, a sealing member, a battery element, and an insulating member. The sealing member is provided between the pair of electrode plates to form a space together with the pair of electrode plates. The battery element includes a positive electrode active material layer, a negative electrode active material layer, and an electrolyte. The positive electrode active material layer is provided on a surface of one of the electrode plates in the space. The negative electrode active material layer is provided on a surface of the other electrode plate in the space. The insulating member is located between the pair of electrode plates on the opposite side of the space from the sealing member. The melting point of the insulating member is lower than the melting point of the sealing member.

[0007] According to this configuration, when the temperature of the battery element rises excessively, the insulating member melts before the sealing member melts. As a result, a pair of electrode plates face each other outside the space, and a discharge occurs between the facing electrode plates. This discharge causes an external short circuit in the battery element, and the SOC (State Of Charge) of the battery element is forcibly reduced. This makes it possible to suppress a further increase in the temperature of the battery element whose temperature has risen excessively. As a result, it is possible to provide an electricity storage module that can quickly suppress a further increase in temperature.

[0008] In the energy storage module according to the present disclosure, the battery element may further include a separator located between the positive electrode active material layer and the negative electrode active material layer. The melting point of the insulating member is preferably lower than the melting point of the separator.

[0009] According to this configuration, the insulating member melts before an internal short circuit occurs due to melting of the separator, so that the electrode plates face each other outside the space earlier, and an external short circuit occurs earlier due to discharge, thereby making it possible to more quickly suppress an increase in temperature of the battery element.

[0010] In the energy storage module according to the present disclosure, the melting point of the insulating member is preferably greater than 60°C.

[0011] According to this configuration, when the temperature of the power storage module is equal to or lower than 60° C., which is a temperature at which the power storage module can operate relatively normally, it is possible to prevent the insulating member from melting.

[0012] The energy storage module according to the present disclosure includes a pair of electrode plates and may further include three or more electrode plates arranged in one direction. It is preferable that the sealing member, the battery element, and the insulating member are provided between adjacent electrode plates in the three or more electrode plates.

[0013] According to this configuration, heat generated by an external short circuit of an excessively heated battery element is transferred to the sealing member between the electrode plates corresponding to the other battery elements. This heat also melts the sealing member between the electrode plates corresponding to the other battery elements, causing external short circuits in the other battery elements due to discharge between the electrode plates. As a result, the SOC of the entire energy storage module is forcibly reduced, and the temperature of the energy storage module is further prevented from increasing. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide an energy storage module that can quickly suppress a further increase in temperature. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing an electricity storage module according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic cross-sectional view showing a state in which a power storage module according to an embodiment of the present disclosure is being charged. [Diagram 3] 1 is a schematic cross-sectional view showing a state in which an energy storage module according to an embodiment of the present disclosure is overcharged and a first insulating member melts away. FIG. [Figure 4] 1 is a schematic cross-sectional view showing a state in which an energy storage module according to an embodiment of the present disclosure is overcharged and a plurality of insulating members are melted off. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an energy storage module according to an embodiment of the present disclosure will be described with reference to the drawings. In the following description of the embodiment, the same or corresponding parts in the drawings are denoted by the same reference characters, and description thereof will not be repeated.

[0017] Fig. 1 is a cross-sectional view showing an energy storage module according to an embodiment of the present disclosure. As shown in Fig. 1, an energy storage module 1 according to an embodiment of the present disclosure includes a pair of electrode plates 10a, 10b, a sealing member 20a, a battery element 30a, and an insulating member 40a.

[0018] Both of the electrode plates 10a, 10b are conductive and specifically made of metal. Each of the electrode plates 10a, 10b has a positive electrode current collector and a negative electrode current collector. The positive electrode current collector and the negative electrode current collector are joined to each other by an adhesive layer. In this embodiment, the positive electrode current collector of one electrode plate 10a of the pair of electrode plates 10a, 10b and the negative electrode current collector of the other electrode plate 10b face each other via the battery element 30a.

[0019] When the power storage module 1 includes only a pair of electrode plates 10a, 10b as electrode plates, the electrode plate 10a may be composed only of a positive current collector plate, and the electrode plate 10b may be composed only of a negative current collector plate.

[0020] The positive electrode current collector may include at least one selected from the group consisting of aluminum (Al), stainless steel, nickel (Ni), chromium (Cr), platinum (Pt), niobium (Nb), iron (Fe), titanium (Ti), and zinc (Zn). The positive electrode current collector is formed of a metal member such as an Al foil.

[0021] The negative electrode current collector may contain at least one selected from the group consisting of aluminum (Al), stainless steel, nickel (Ni), chromium (Cr), platinum (Pt), niobium (Nb), iron (Fe), titanium (Ti), and zinc (Zn). The negative electrode current collector is formed of a metal member such as an Al foil.

[0022] The sealing member 20a is provided between the pair of electrode plates 10a, 10b to form a (first) space S1 together with the pair of electrode plates 10a, 10b. The space S1 is an enclosed space.

[0023] The sealing member 20a has, for example, a rectangular cylindrical shape. The sealing member 20a is formed by hardening a resin material such as a hot melt material, a thermoplastic resin, a thermosetting resin, or a photocurable resin. Examples of materials constituting the sealing member 20a include polyolefin resins such as polyethylene (PE) or polypropylene (PP), or polyester resins such as polyethylene terephthalate (PET).

[0024] The battery element 30a includes a positive electrode active material layer 31, a negative electrode active material layer 32, a separator 33, and an electrolyte .

[0025] The positive electrode active material layer 31 is provided on one surface of the electrode plate 10a in the space S1. Specifically, the positive electrode active material layer 31 is provided on the positive electrode current collector plate of the electrode plate 10a.

[0026] The positive electrode active material layer includes a positive electrode active material, a conductive material, and a binder. The positive electrode active material may be, for example, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, or lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 etc.), lithium nickel cobalt aluminate, and lithium iron phosphate.

[0027] The conductive material may include, for example, at least one selected from the group consisting of carbon black (such as acetylene black), vapor grown carbon fiber (VGCF), carbon nanotubes (CNT), and graphene flakes.

[0028] The binder may include, for example, at least one selected from the group consisting of carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyvinylidene fluoride (PVdF), and polytetrafluoroethylene (PTFE).

[0029] The negative electrode active material layer 32 is provided on the surface of the other electrode plate 10b in the space S1. The negative electrode active material layer 32 is specifically provided on the negative electrode current collector plate of the electrode plate 10b.

[0030] The negative electrode active material layer 32 includes a negative electrode active material and a binder. The negative electrode active material may be, for example, a carbon-based negative electrode active material such as natural graphite, graphitizable carbon, or non-graphitizable carbon, or may be an alloy-based negative electrode active material containing silicon (Si), tin (Sn), or the like. The binder may be a material that can be used as a binder contained in a positive electrode active material layer.

[0031] The separator 33 is located between the positive electrode active material layer 31 and the negative electrode active material layer 32. The separator 33 is formed, for example, in a sheet shape. The thickness of the separator 33 is not particularly limited, but may be, for example, about 20 μm. The separator 33 is joined to the sealing member 20. Therefore, the space S1 is further divided into two spaces by the separator 33.

[0032] Examples of the separator 33 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyamide resins such as nylon and aromatic polyamide (aramid), woven or nonwoven fabrics made of polypropylene, polyethylene terephthalate (PET), methyl cellulose, etc. The separator 33 may be reinforced with a vinylidene fluoride resin compound.

[0033] Separator 33 may have, for example, a multi-layer structure, specifically a three-layer structure. Separator 33 may include, for example, a PP layer, a PE layer, and a PP layer. The PP layer, the PE layer, and the PP layer may be laminated in this order.

[0034] The electrolyte 34 is disposed in the space S1. In this embodiment, the electrolyte 34 is an electrolytic solution injected into the space S1. Specifically, the electrolyte 34 is a non-aqueous electrolytic solution or an aqueous electrolytic solution, for example, a mixed solvent of EC / EMC / DMC. The electrolyte 34 may be a solid electrolyte. When the electrolyte 34 is a solid electrolyte, the electrolyte 34 is provided between the positive electrode active material layer 31 and the negative electrode active material layer 32, and a separator may not be provided in the battery element 30a.

[0035] The insulating member 40a is located between the pair of electrode plates 10a, 10b on the opposite side of the space S1 as viewed from the sealing member 20a. The insulating member 40a is preferably arranged on the opposite side of the space S1 as viewed from the sealing member 20a so that the pair of electrode plates 10a, 10b do not directly face each other. It is also preferable that the insulating member 40a is arranged only in the space between the pair of electrode plates 10a, 10b.

[0036] Examples of materials constituting the insulating member 40a include polyolefin resins such as polyethylene (PE) and polypropylene (PP), and oils and fats such as paraffin.

[0037] The melting point of the insulating member 40a is lower than that of the sealing member 20a. The melting point of the insulating member 40a is preferably lower than that of the separator 33. The difference between the melting point of the sealing member 20a and that of the insulating member 40a is preferably 20° C. or higher, more preferably 30° C. or higher, and even more preferably 40° C. or higher. Considering that the temperature at which the energy storage module 1 can normally operate is, for example, about 50° C. or lower to 60° C. or lower, the melting point of the insulating member 40a is preferably higher than 60° C. The melting point of the separator 33 is preferably higher than that of the sealing member 20a. In addition, when the electrolyte 34 is a solid electrolyte, the operating temperature of the energy storage module 1 may be as high as about 80° C., so that the sealing member 20a and the insulating member 40a may have melting points of 80° C. or higher or 90° C. or higher.

[0038] Considering the melting points of the above-mentioned materials, the following combinations of the sealing member 20a, the separator 33, and the insulating member 40a may be mentioned, for example.

[0039] When the sealing member 20a is PE (melting point is about 120°C) and the separator 33 is a porous film made of PE (melting point is about 120°C) or PP (melting point is about 160°C) or a woven or nonwoven fabric made of aromatic polyamide (aramid) (melting point is about 200°C to 300°C), paraffin (melting point is about 70°C to 100°C) can be used as the material constituting the insulating member 40a. When the sealing member 20a is PP (melting point is about 160°C) and the separator 33 is a porous film made of PP (melting point is about 160°C) or a woven or nonwoven fabric made of aromatic polyamide (aramid) (melting point is about 200°C to 300°C), paraffin (melting point is about 70°C to 100°C) or PE (melting point is about 120°C) can be used as the material constituting the insulating member 40a. When the sealing member 20a is a woven or nonwoven fabric made of PET (melting point of approximately 260°C) and the separator 33 is a woven or nonwoven fabric made of aromatic polyamide (aramid) (melting point of approximately 200°C to 300°C), paraffin (melting point of approximately 70°C to 100°C), PE (melting point of approximately 120°C), or PP (melting point of approximately 160°C) can be used as the material constituting the insulating member 40a.

[0040] The energy storage module 1 according to this embodiment includes three or more electrode plates 10 arranged in one direction. The three or more electrode plates 10 arranged in one direction include the pair of electrode plates 10a, 10b described above. As shown in Fig. 1, the energy storage module 1 according to this embodiment specifically includes four electrode plates 10, but may include five or more electrode plates 10.

[0041] The energy storage module 1 according to this embodiment further includes a third electrode plate 10c located on the opposite side to the other electrode plate 10b (second electrode plate 10b) as viewed from one electrode plate 10a (first electrode plate 10a) of the pair of electrode plates 10. The energy storage module 1 further includes a fourth electrode plate 10d located on the opposite side to the first electrode plate 10a as viewed from the second electrode plate 10b.

[0042] The sealing members 20, battery elements 30, and insulating members 40 are provided between adjacent electrode plates 10 in three or more electrode plates 10 (four electrode plates 10c, 10a, 10b, and 10d in this embodiment). That is, in this embodiment, the energy storage module 1 includes a plurality of sealing members 20, a plurality of battery elements 30, and a plurality of insulating members 40. The energy storage module 1 according to this embodiment is a so-called bipolar battery.

[0043] The multiple sealing members 20 include a (first) sealing member 20a, and further include a second sealing member 20b and a third sealing member 20c.

[0044] The second sealing member 20b is provided between the first electrode plate 10a and the third electrode plate 10c to form a second space S2 together with the first electrode plate 10a and the third electrode plate 10c. The second space S2 is a sealed space. The third sealing member 20c is provided between the second electrode plate 10b and the fourth electrode plate 10d to form a third space S3 together with the second electrode plate 10b and the fourth electrode plate 10d. The third space S3 is a sealed space.

[0045] The plurality of battery elements 30 includes a (first) battery element 30a, and further includes a second battery element 30b and a third battery element 30c.

[0046] The positive electrode active material layer 31 of the second battery element 30b is provided on the surface of the third electrode plate 10c in the second space S2. The negative electrode active material layer 32 of the second battery element 30b is provided on the surface of the first electrode plate 10a in the second space S2. A separator 33 is also located between the positive electrode active material layer 31 and the negative electrode active material layer 32. An electrolyte 34 is also provided in the space S2.

[0047] The positive electrode active material layer 31 of the third battery element 30c is provided on the surface of the second electrode plate 10b in the third space S3. The negative electrode active material layer 32 of the third battery element 30c is provided on the surface of the fourth electrode plate 10d in the third space S3. A separator 33 is also located between the positive electrode active material layer 31 and the negative electrode active material layer 32. An electrolyte 34 is also provided in the space S3.

[0048] The multiple insulating members 40 include a (first) insulating member 40a, and further include a second insulating member 40b and a third insulating member 40c.

[0049] The second insulating member 40b is located between the first electrode plate 10a and the third electrode plate 10c on the opposite side of the second space S2 from the second sealing member 20b. The third insulating member 40c is located between the second electrode plate 10b and the fourth electrode plate 10d on the opposite side of the third space S3 from the third sealing member 20c.

[0050] The multiple insulating members 40 may be connected to each other on the side of the electrode plate 10. The multiple insulating members 40 may be integrally configured by being connected to each other.

[0051] The energy storage module 1 may further include a restraining member. The restraining member may restrain the plurality of electrode plates 10 and the plurality of battery elements 30 from both sides of the electrode plates 10 (the third electrode plate 10c and the fourth electrode plate 10d in this embodiment) located at both ends in the direction in which the plurality of electrode plates 10 are arranged (the stacking direction in the energy storage module 1).

[0052] Next, a state in which the temperature of the power storage module 1 according to this embodiment has excessively increased will be described.

[0053] Fig. 2 is a schematic cross-sectional view showing a state in which a power storage module according to an embodiment of the present disclosure is being charged. As shown in Fig. 2, a voltage is applied to the power storage module 1 from an external DC power source, causing a charging current to flow through the power storage module 1. In Fig. 2 and subsequent figures, the charging current is indicated by a thick black arrow.

[0054] In the power storage module 1, the charging current flows in the order of the third electrode plate 10c, the second battery element 30b, the first electrode plate 10a, the first battery element 30a, the second electrode plate 10b, the third battery element 30c, and the fourth electrode plate 10d.

[0055] When the energy storage module 1 is charged, the temperature of each battery element 30 rises. If a voltage is applied and a charging current continues to flow even though the energy storage module 1 is sufficiently charged, each battery element 30 generates excessive heat. In particular, in this embodiment, the first battery element 30a located between the second battery element 30b and the third battery element 30c generates the most excessive heat. This heat generation occurs more significantly when the battery element 30a is restrained by the above-mentioned restraining member, thereby suppressing the expansion of the battery element 30a.

[0056] When the temperature of the battery element 30a rises excessively, the heat generated in the battery element 30a is transferred to the insulating member 40a via the sealing member 20a, etc. This causes the temperature of the insulating member 40a to rise. When the temperature of the insulating member 40a reaches its melting point, the insulating member 40a melts, and eventually the insulating member 40a melts down from between the pair of electrode plates 10a, 10b.

[0057] 3 is a schematic cross-sectional view showing a state in which the energy storage module according to the embodiment of the present disclosure is overcharged and the first insulating member melts down. As shown in FIG. 3, when the insulating member 40a (see FIG. 2) melts down, the pair of electrode plates 10a, 10b face each other outside the space S1. Discharge occurs between the pair of electrode plates 10a, 10b facing each other.

[0058] The above discharge causes an external short circuit in the battery element 30a. In Fig. 3 and subsequent figures, the external short circuit is indicated by a hollow arrow. This external short circuit forcibly reduces the SOC of the battery element 30a. This makes it possible to prevent the temperature of the battery element 30a, whose temperature has already risen excessively, from increasing further. As a result, it is possible to provide a power storage module 1 that can prevent a further increase in temperature at an early stage.

[0059] Note that discharging between the first electrode plate 10a and the second electrode plate 10b continues to overcharge the other battery elements 30 (the second battery element 30b and the third battery element 30c in this embodiment) in the power storage module 1. A charging current flows in the order of the third electrode plate 10c, the second battery element 30b, the first electrode plate 10a, the second electrode plate 10b, the third battery element 30c, and the fourth electrode plate 10d.

[0060] When an external short circuit occurs in the first battery element 30a, heat locally generated by the external short circuit is transferred to the second insulating member 40b and the third insulating member 40c via the first electrode plate 10a and the second electrode plate 10b, respectively. This causes the temperatures of the second insulating member 40b and the third insulating member 40c to temporarily rise further. When the second insulating member 40b and the third insulating member 40c reach their respective melting points, the second insulating member 40b and the third insulating member 40c melt, and eventually the second insulating member 40b and the third insulating member 40c also melt down from between the electrode plates 10.

[0061] 4 is a schematic cross-sectional view showing a state in which the power storage module according to an embodiment of the present disclosure is overcharged and a plurality of insulating members are melted down. As shown in FIG. 4, when the second insulating member 40b (see FIG. 3) is melted down, the first electrode plate 10a and the third electrode plate 10c face each other outside the second space S2. Discharge occurs between the first electrode plate 10a and the third electrode plate 10c facing each other. The discharge causes an external short circuit in the second battery element 30b. This external short circuit forcibly reduces the SOC of the second battery element 30b.

[0062] Furthermore, when the third insulating member 40c (see FIG. 3) melts down, the second electrode plate 10b and the fourth electrode plate 10d face each other outside the third space S3. Discharge occurs between the facing second electrode plate 10b and fourth electrode plate 10d. This discharge causes an external short circuit in the third battery element 30c. This external short circuit forcibly reduces the SOC of the third battery element 30c.

[0063] In this manner, the SOC of at least one of the second battery element 30b and the third battery element 30c is forcibly decreased, thereby suppressing a further increase in the temperature of at least one of the second battery element 30b and the third battery element 30c. As a result, the SOC of the entire power storage module 1 is forcibly decreased, and a further increase in the temperature of the power storage module 1 can be further suppressed.

[0064] In the above description of the embodiments, configurations that can be combined may be combined with each other.

[0065] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] 1 Energy storage module, 10 Electrode plate, 10a First electrode plate, 10b Second electrode plate, 10c Third electrode plate, 10d Fourth electrode plate, 20 Sealing member, 20a First sealing member, 20b Second sealing member, 20c Third sealing member, 30 Battery element, 30a First battery element, 30b Second battery element, 30c Third battery element, 31 Positive electrode active material layer, 32 Negative electrode active material layer, 33 Separator, 34 Electrolyte, 40 Insulating member, 40a First insulating member, 40b Second insulating member, 40c Third insulating member, S1 (First) space, S2 Second space, S3 Third space.

Claims

1. A pair of electrode plates; a sealing member provided between the pair of electrode plates to form a space together with the pair of electrode plates; a battery element including a positive electrode active material layer provided on a surface of one of the electrode plates in the space, a negative electrode active material layer provided on a surface of the other electrode plate in the space, and an electrolyte; an insulating member located between the pair of electrode plates on the opposite side of the space as viewed from the sealing member, The insulating member has a melting point lower than a melting point of the sealing member.

2. the battery element further includes a separator located between the positive electrode active material layer and the negative electrode active material layer, The energy storage module according to claim 1 , wherein the insulating member has a melting point lower than a melting point of the separator.

3. The energy storage module according to claim 1 , wherein the insulating member has a melting point of more than 60° C.

4. The electrode plate further includes a pair of the electrode plates and three or more electrode plates arranged in one direction, The energy storage module according to claim 1 , wherein the sealing member, the battery element, and the insulating member are provided between adjacent electrode plates in three or more of the electrode plates.

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