JP7027768B2 - Power storage module and power storage pack - Google Patents

Description

The present invention relates to a power storage module and a power storage pack.

Power storage elements that can be charged and discharged are used in various devices such as mobile phones and automobiles. Among them, vehicles powered by electric energy such as electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) require a large amount of energy, so they are equipped with a large-capacity power storage module equipped with multiple power storage elements. There is.

In such a power storage module, when the temperature of any one of the power storage elements rises excessively for some reason, although it is not in a normal use state, the heat of the power storage element is conducted to the adjacent power storage element to conduct the adjacent power storage. The element is heated. As a result, when the active material of the electrode of the adjacent power storage element is heated to the self-heating temperature or higher, the adjacent power storage element also becomes overheated due to self-heat generation and further heats the adjacent power storage element in a chain reaction. A large number of power storage elements may become overheated.

When using a power storage element in which a metal case is covered with a resin film, if the power storage element becomes overheated, the resin film melts and the metal cases come into contact with each other to promote heat conduction, resulting in an overheated state. Chain is likely to occur. In particular, when a metal case is used as an electrode, or when the metal case has an abnormal potential due to some abnormality, an abnormal current is applied to the adjacent power storage element by electrically contacting the case of the adjacent power storage element. It may cause overheating.

In the conventional power storage module, heat insulation is performed by providing an air layer of about 10 mm and a partition member (for example, a mica integrated material) having a thickness of about several mm between a plurality of power storage elements.

For example, Japanese Patent Application Laid-Open No. 2015-195149 discloses a technique for suppressing heat conduction of a power storage element to an adjacent power storage element. In the power storage module described in the publication, heat conduction between the power storage elements is suppressed by a partition member formed of the mica integrated material.

JP-A-2015-195149

In recent years, it has been desired to further increase the capacity of the power storage element and the power storage module, and further increase the energy density (storage amount per unit volume).

When the capacity and energy density of each power storage element are increased, the energy and heat released from the power storage element when a certain power storage element becomes overheated also become very large. By increasing the thickness of the air layer and the partition member between the power storage elements, the heat insulating property can be improved, but in these methods, the energy density of the power storage module is lowered. Therefore, there is a demand for new measures that can prevent a chain of overheated states between storage elements without lowering the energy density.

Therefore, it is an object of the present invention to provide a power storage module and a power storage pack that have a high energy density and can prevent a chain of overheated states between power storage elements.

The power storage module according to one aspect of the present invention, which has been made to solve the above problems, includes a plurality of power storage elements and a partition member arranged between the power storage elements, and the partition member is mainly composed of inorganic fibers. It has an inorganic paper sheet to be used, a bag body for accommodating the inorganic paper sheet in an internal space, and a liquid containing water as a main component and impregnating the inorganic paper sheet.

The power storage module of the present invention has a high energy density and can prevent a chain of overheated states between power storage elements.

It is a schematic perspective view which shows the power storage module of one Embodiment of this invention. It is a schematic cross-sectional view of the partition member of the power storage module of FIG. It is a schematic plan view of the storage pack provided with the power storage module of FIG.

The power storage module according to one aspect of the present invention includes a plurality of power storage elements and a partition member arranged between the power storage elements, and the partition member includes an inorganic paper sheet mainly composed of inorganic fibers and an internal space. It has a bag body for accommodating the inorganic paper sheet and a liquid containing water as a main component and impregnating the inorganic paper sheet.

In the power storage module, the partition member includes an inorganic paper sheet mainly composed of inorganic fibers, a bag body for accommodating the inorganic paper sheet in an internal space, and a liquid containing water as a main component and impregnating the inorganic paper sheet. Therefore, when any of the power storage elements is in a heated state, the water in the liquid impregnated in the inorganic paper sheet evaporates to take heat of the power storage element as vaporization heat and transfer it to the adjacent power storage element. Reduce heat. Therefore, the power storage module can prevent a chain of superheated states between the power storage elements.

The water content of the inorganic paper sheet is preferably 30% by volume or more and 80% by volume or less. With this configuration, sufficient heat can be taken as heat of vaporization, and sufficient strength can be imparted to the inorganic paper sheet to appropriately form the partition member.

It is preferable that the power storage element is formed in a rectangular parallelepiped shape, and the partition member is pressed and held between the long side surfaces of the power storage element. With this configuration, no dead space is formed between the power storage element and the partition member, so that the energy density of the power storage module can be further increased.

A storage pack according to another aspect of the present invention includes the plurality of power storage modules and a holder for holding the plurality of power storage modules. In the power storage pack, each power storage module has the partition member, so that a chain of overheated states between the power storage elements can be prevented.

The "main component" means the component having the highest mass content.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

FIG. 1 shows a power storage module 1 according to an embodiment of the present invention. The power storage module 1 includes a plurality of power storage elements 2 and a partition member 3 arranged one by one between the power storage elements 2. Further, the power storage module 1 includes a holding member 4 that holds the power storage element 2 and the partition member 3, a bus bar 5 that electrically connects the plurality of power storage elements 2, and a cooling member 6 that cools the plurality of power storage elements 2. Further prepare.

The power storage element 2 may be enclosed in the case 7 in a state where an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator is immersed in an electrolytic solution.

The case 7 may be, for example, a flexible bag formed of a laminated sheet in which a metal foil and a resin film are joined, or may be a rigid container formed of a resin or a metal. As shown in the figure, the case 7 may be a box-shaped (rectangular parallelepiped) metal container having excellent strength and reducing dead space.

The case 7 is provided with a pair of external terminals (positive electrode external terminal 8 and negative electrode external terminal 9). The positive electrode external terminal 8 is electrically connected to the positive electrode plate of the electrode body, and the negative electrode external terminal 9 is electrically connected to the negative electrode plate of the electrode body.

As the electrode body, it is preferable to use a laminated type formed by laminating a plurality of flat plate-shaped positive electrode plates, negative electrode plates and separators because the space efficiency can be improved and the energy density can be increased. Alternatively, as the electrode body, a winding type formed by winding a long positive electrode plate, a negative electrode plate, and a separator in a flat cross-sectional view may be used.

The number of positive electrode plates laminated in the laminated type electrode body can be, for example, 40 to 60 in order to increase the capacity of the power storage element 2. In the laminated type electrode body, it is preferable that the negative electrode plates are arranged outside the positive electrode plate on both sides in the stacking direction in order to suppress an internal short circuit due to electrodeposition. Therefore, the number of negative electrode plates is preferably one more than the number of positive electrode plates.

The positive electrode plate of the electrode body can be configured to have a foil-shaped or sheet-shaped positive electrode base material having conductivity and a positive electrode active material layer laminated on both sides of the positive electrode base material.

As the material of the positive electrode base material of the positive electrode plate, a metal such as aluminum, copper, iron, nickel or an alloy thereof or an alloy thereof is used. Among these, aluminum, aluminum alloys, copper and copper alloys are preferable, and aluminum and aluminum alloys are more preferable, from the viewpoint of the balance between high conductivity and cost. Further, as the shape of the positive electrode base material, a foil, a vapor-deposited film and the like can be mentioned, and the foil is preferable from the viewpoint of cost. That is, aluminum foil is preferable as the positive electrode base material. Examples of aluminum or aluminum alloy include A1085P and A3003P specified in JIS-H4000 (2014).

The positive electrode active material layer of the positive electrode plate is a porous layer formed from a so-called mixture containing the positive electrode active material. Further, the mixture forming the positive electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary.

Examples of the positive electrode active material include composite oxides (Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x ) represented by Li _x MO _y (M represents at least one kind of transition metal). MnO ₃ , Li _x Ni _α Co _(1-α) O ₂ , Li _x Ni _α Mn _β Co _(1-α-β) O ₂ , Li _x Ni _α Mn _(2-α) O ₄ etc.), Li _w Polyanionic compounds (LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ ) represented by Me _x (XO _y ) _z (Me represents at least one kind of transition metal, X represents, for example, P, Si, B, V, etc.). , Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.). The elements or polyanions in these compounds may be partially substituted with other elements or anion species. In the positive electrode active material layer, one kind of these compounds may be used alone, or two or more kinds may be mixed and used. Further, the crystal structure of the positive electrode active material is preferably a layered structure or a spinel structure.

The negative electrode plate has a conductive foil-like or sheet-like negative electrode base material and a porous negative electrode active material layer laminated on both sides of the negative electrode base material.

Copper or a copper alloy is preferable as the material of the negative electrode base material of the negative electrode plate. Further, as the shape of the negative electrode base material, foil is preferable. That is, copper foil is preferable as the negative electrode base material of the negative electrode plate. Examples of the copper foil used as the negative electrode base material include rolled copper foil and electrolytic copper foil.

The negative electrode active material layer is a porous layer formed from a so-called mixture containing a negative electrode active material. Further, the mixture forming the negative electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary.

As the negative electrode active material, a material capable of occluding and releasing lithium ions is preferably used. Specific negative electrode active materials include metals such as lithium and lithium alloys, metal oxides, polyphosphate compounds, and carbon materials such as graphite and amorphous carbon (easy graphitizing carbon or non-graphitizable carbon). And so on.

Among the negative electrode active materials, it is preferable to use Si, Si oxide, Sn, Sn oxide or a combination thereof from the viewpoint of setting the discharge capacity per unit facing area between the positive electrode plate and the negative electrode plate in a suitable range. , Si oxide is particularly preferable. It should be noted that Si and Sn can have a discharge capacity of about three times that of graphite when made into an oxide.

The separator is formed of a sheet-like or film-like material in which the electrolytic solution is infiltrated. As the material for forming the separator, for example, a woven fabric, a non-woven fabric, or the like can be used, but a sheet-like or film-like resin having porosity is typically used. This separator separates the positive electrode plate and the negative electrode plate, and holds the electrolytic solution between the positive electrode plate and the negative electrode plate.

The main components of this separator include, for example, polyethylene, polypropylene, an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, a polyolefin derivative such as chlorinated polyethylene, and an ethylene-propylene copolymer. Polyolefins such as coalesced, polyethylene such as polyethylene terephthalate and copolymerized polyester and the like can be adopted. Among them, polyethylene and polypropylene, which are excellent in electrolytic solution resistance, durability and weldability, are preferably used as the main component of the separator.

The separator preferably has a heat resistant layer or an oxidation resistant layer on both sides or one side (preferably the surface facing the positive electrode plate). The “heat-resistant layer” means a layer that prevents damage to the separator due to heat and more reliably prevents a short circuit between the positive electrode plate and the negative electrode plate. On the other hand, the "oxidation-resistant layer" means a layer that protects the separator in a high voltage environment but does not give the separator sufficient heat resistance.

The heat-resistant layer or the antioxidative layer of the separator can be configured to include a large number of inorganic particles and a binder connecting the inorganic particles.

The main components of the inorganic particles include, for example, alumina, silica, zirconia, titania, magnesia, ceria, itria, zinc oxide, oxides such as iron oxide, silicon nitride, titanium nitride, nitrides such as boron nitride, silicon carbide, and carbonic acid. Calcium, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin ray, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate And so on. Among them, alumina, silica and titania are particularly preferable as the main components of the inorganic particles of the heat-resistant layer or the oxidation-resistant layer.

The electrode body preferably has a positive electrode tab extending from the positive electrode plate and connecting the positive electrode plate to the positive electrode external terminal 8, and a negative electrode tab extending from the negative electrode plate and connecting the negative electrode plate to the negative electrode external terminal 9.

The positive electrode tab and the negative electrode tab can be formed by extending the positive electrode base material and the negative electrode base material of the positive electrode plate and the negative electrode plate so as to project in a band shape from the rectangular region in which the active material layer is laminated.

The positive electrode tab and the negative electrode tab are arranged so as to project in the same direction from the positive electrode plate and the negative electrode plate in order to reduce the dead space in the case 7 so as not to overlap each other in the stacking direction of the electrode bodies. Is preferable. The positive electrode tab and the negative electrode tab extending from each positive electrode plate and the negative electrode plate are laminated and bundled, respectively, and are attached to the positive electrode external terminal 8 and the negative electrode external terminal 9, or the positive electrode external terminal 8 and the negative electrode external terminal 9. It can be connected to a current collecting member and a negative electrode current collecting member.

As the electrolytic solution enclosed in the case 7 together with the electrode body, a known electrolytic solution usually used for a power storage element can be used, for example, a cyclic carbonate such as ethylene carbonate, propylene carbonate or butylene carbonate, or diethyl carbonate, dimethyl carbonate or ethyl. A solution in which lithium hexafluorophosphate (LiPF ₆ ) or the like is dissolved in a solvent containing a chain carbonate such as methyl carbonate can be used.

As shown in detail in FIG. 2, the partition member 3 includes an inorganic paper sheet 10 mainly composed of inorganic fibers, a bag body 11 for accommodating the inorganic paper sheet 10 in an internal space, and an inorganic paper sheet 10 containing water as a main component. Has a liquid 12 to be impregnated with.

The inorganic paper sheet 10 is a sheet formed by making paper from inorganic fibers, and has voids for holding a liquid between the inorganic fibers. That is, the inorganic paper sheet 10 uniformly holds the liquid 12 in the plan view of the partition member 3.

Examples of the inorganic fiber forming the inorganic paper sheet 10 include glass fiber, carbon fiber, rock wool, metal fiber and the like, and among them, glass having a diameter and length suitable for papermaking can be manufactured at a relatively low cost. Fiber is preferred.

The lower limit of the average thickness of the inorganic paper sheet 10 is preferably 0.2 mm, more preferably 0.3 mm. On the other hand, the upper limit of the average thickness of the inorganic paper sheet 10 is preferably 1.0 mm, more preferably 0.8 mm. By setting the average thickness of the inorganic paper sheet 10 to be equal to or greater than the lower limit, the inorganic paper sheet 10 can form sufficient voids in the bag 11 to hold a sufficient amount of liquid 12. Further, by setting the average thickness of the inorganic paper sheet 10 to be equal to or less than the upper limit, the occupied volume of the inorganic paper sheet 10 in the power storage module 1 can be reduced and the energy density can be improved.

The lower limit of the water content of the inorganic paper sheet 10 (the amount of water in the liquid 12 impregnated in the inorganic paper sheet 10) is preferably 30% by volume, more preferably 40% by volume. On the other hand, the upper limit of the water content of the inorganic paper sheet 10 is preferably 80% by volume, more preferably 75% by volume. By setting the water content of the inorganic paper sheet 10 to be equal to or higher than the lower limit, the amount of heat that can be taken as heat of vaporization of water can be sufficiently increased. Further, by setting the water content of the inorganic paper sheet 10 to the upper limit or less, the inorganic paper sheet 10 having sufficient strength can be used, so that the inorganic paper sheet 10 functions as a heat insulating material after evaporation of water. Further, by setting the water content of the inorganic paper sheet 10 to the upper limit or less, it is possible to prevent liquid from interposing between the inorganic paper sheet 10 and the bag body 11, so that the partition member 3 presses and holds between the power storage elements 1. The pressure force at the time of being wiped can be received by the inorganic paper sheet 10, and it is possible to prevent the internal pressure of the bag 11 from rising excessively regardless of the temperature rise.

The lower limit of the porosity of the inorganic paper sheet 10 under atmospheric pressure is preferably 70%, more preferably 80%. On the other hand, as the upper limit of the porosity of the inorganic paper sheet 10 under atmospheric pressure, 97% is preferable, and 95% is more preferable. By setting the porosity of the inorganic paper sheet 10 under atmospheric pressure to be equal to or higher than the lower limit, the inorganic paper sheet 10 has sufficient heat insulating properties. Further, by setting the void ratio of the inorganic paper sheet 10 under atmospheric pressure to the above upper limit or less, the inorganic paper sheet 10 has sufficient compressive strength, so that the inorganic paper is after the water in the liquid 12 evaporates. Since the sheet 10 retains the voids and functions as a heat insulating material, the thermal conductivity of the partition member 3 can be reduced. The "void ratio" is calculated by calculating the volume per unit area of the inorganic paper sheet using the thickness measured by the sickness gauge, and from the specific gravity of the inorganic fiber and the weight of the inorganic fiber used per unit area of the inorganic paper sheet. It is a value calculated as the volume of the inorganic fiber per unit area of the inorganic paper sheet and the ratio of the difference between these volumes to the volume per unit area of the inorganic paper sheet.

Further, the lower limit of the porosity of the inorganic paper sheet 10 in a state where a pressure of 200 kPa is applied to the power storage element 2 is preferably 45%, more preferably 50%. On the other hand, the upper limit of the porosity of the inorganic paper sheet 10 in a state where a pressure of 200 kPa is applied to the power storage element 2 is preferably 80%, more preferably 75%. The inorganic paper sheet 10 is not only compressed by the decompression of the bag body 11, but can also be sandwiched between the power storage elements 2 in the power storage module 1 and compressed at a pressure of about 200 kPa, as will be described later. Therefore, by setting the porosity of the inorganic paper sheet 10 in the state where the pressure of 200 kPa is applied to the power storage element 2 to the above lower limit or more, the partition member 3 reduces the thickness even after the water in the liquid 12 evaporates. It is held above a certain level and has sufficient voids. As a result, the inorganic paper sheet 10 can function as a heat insulating agent after the water in the liquid 12 evaporates. Further, by setting the porosity of the inorganic paper sheet 10 in a state where a pressure of 200 kPa is applied to the power storage element 2 to the above upper limit or less, the formation of the inorganic paper sheet 10 becomes relatively easy, so that the inorganic paper sheet 10 is relatively inexpensive. The paper sheet 10 can be used.

The lower limit of the average diameter of the inorganic fibers forming the inorganic paper sheet 10 is preferably 0.2 μm, more preferably 0.3 μm. On the other hand, the upper limit of the average diameter of the inorganic fibers forming the inorganic paper sheet 10 is preferably 1.5 μm, more preferably 1.0 μm. By setting the average diameter of the inorganic fibers forming the inorganic paper sheet 10 to be equal to or greater than the lower limit, the inorganic paper sheet 10 can be made to have sufficient strength. Further, by setting the average diameter of the inorganic fibers forming the inorganic paper sheet 10 to be equal to or less than the upper limit, the inorganic paper sheet 10 can be made to have sufficient heat insulating properties.

The inorganic paper sheet 10 can include a binder. As the binder contained in the inorganic paper sheet 10, for example, a polymer binder such as acrylic resin, polyester, polypropylene or fluororesin, for example, an inorganic binder such as sodium silicate can be used.

The bag body 11 is formed of a sheet having a gas barrier property. The bag body 11 may be formed by folding one sheet and adhering the outer edges (three sides) other than the bending line, or by stacking the two sheets and adhering the entire outer edge (four sides). It may be formed by.

It is preferable that the bag 11 has a metal layer 13 in order to secure a high degree of gas barrier property, that is, the sheet forming the bag 11 has the metal layer 13. Since the bag 11 has the metal layer 13, the life of the partition member 3 and thus the power storage module 1 can be sufficiently extended.

Examples of the material of the metal layer 13 of the bag 11 include aluminum, stainless steel, nickel, and copper. Among them, aluminum, which is inexpensive and has excellent gas barrier properties and handleability, is particularly preferable as the material of the metal layer 13 of the bag body 11.

The lower limit of the average thickness of the metal layer 13 of the bag 11 is preferably 40 μm, more preferably 80 μm. On the other hand, the upper limit of the average thickness of the metal layer 13 of the bag 11 is preferably 300 μm, more preferably 200 μm. By setting the average thickness of the metal layer 13 of the bag 11 to be equal to or greater than the lower limit, the gas barrier property of the bag 11 is increased, so that the partition member 3 can be provided with a sufficient life. Further, by setting the average thickness of the metal layer 13 of the bag 11 to be equal to or less than the upper limit, it is possible to prevent the partition member 3 from becoming thick and lowering the energy density of the power storage module 1, and to increase the manufacturing cost. Can be prevented.

It is preferable that the bag 11 (that is, the sheet forming the bag 11) further has a resin coating layer 14 that protects the outer surface of the metal layer 13. The coating layer 14 of the bag 11 covers the surface of the metal layer 13 to prevent the metal layer 13 from being damaged by scratches or the like and impairing the gas barrier property, thereby improving the handleability of the partition member 3. Specifically, as the sheet forming the bag 11, it is preferable to use a laminated sheet in which the metal foil constituting the metal layer 13 and the resin film constituting the coating layer 14 are joined.

Examples of the material of the coating layer 14 include polypropylene, polyphenylene sulfide, polyethylene terephthalate and the like.

The lower limit of the average thickness of the coating layer 14 is preferably 10 μm, more preferably 15 μm. On the other hand, the upper limit of the average thickness of the covering layer 14 is preferably 200 μm, more preferably 100 μm. By setting the average thickness of the coating layer 14 to be equal to or higher than the lower limit, the strength of the coating layer 14 becomes sufficient and the protection of the metal layer 13 is ensured. Further, by setting the average thickness of the covering layer 14 to be equal to or less than the upper limit, it is possible to prevent the thickness of the partition member 3 from increasing.

It is preferable that the sheet forming the bag 11 further has a resin adhesive layer 15 on the inner surface side of the metal layer 13 so as to enable adhesion by heat sealing. Therefore, that is, as the sheet forming the bag body 11, it is preferable to use a laminated sheet in which the metal foil constituting the metal layer 13 and the resin film constituting the adhesive layer 15 are bonded to each other, and the metal foil forming the metal layer 13 is preferably used. It is more preferable to use a laminated sheet in which the resin film forming the coating layer 14 and the resin film forming the adhesive layer 15 are bonded to each other.

It is preferable that the bag body 11 is configured so that when the water in the liquid 12 evaporates and the internal pressure rises, the bag body 11 is opened and the water vapor inside is released to the outside. As a configuration in which the bag body 11 is opened by an increase in the internal pressure, a configuration in which the sheet forming the bag body 11 is torn may be used, but a configuration in which the adhesive portion of the sheet is peeled off is convenient. By configuring the bag 11 to open when the internal pressure rises in this way, it is possible to prevent the pressure applied to the power storage element 2 from rising excessively and to keep the evaporation temperature of water in the liquid 12 low. The temperature rise of the partition member 3 is suppressed, and excessive heat can be prevented from being transferred from the overheated power storage element 2 to the adjacent power storage element 2 via the partition member 3.

The bag body 11 is preferably one that does not break due to compression of the module, preferably does not break at 1200 kP as the side compression pressure in the module, and more preferably does not break at 2000 kPa. As a result, it is possible to withstand an increase in the pressing force at the end of the life, and it is possible to obtain a highly reliable partition member. Further, regarding the internal pressure, the temperature of the partition member 3 can be kept low by bursting due to an internal pressure increase of 150 kPa (assuming 1.5 atm), more preferably 100 kPa (assuming 1 atm). Therefore, it is possible to reliably prevent the chain of overheated states of the power storage element 2.

Examples of the material of the adhesive layer 15 include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and the like.

The lower limit of the average thickness of the adhesive layer 15 is preferably 10 μm, more preferably 15 μm. On the other hand, the upper limit of the average thickness of the adhesive layer 15 is preferably 200 μm, more preferably 100 μm. Sufficient heat-sealing properties can be obtained by setting the average thickness of the adhesive layer 15 to be equal to or greater than the lower limit. Further, by setting the average thickness of the adhesive layer 15 to be equal to or less than the upper limit, it is possible to prevent the thickness of the partition member 3 from increasing.

As the liquid 12, water or water to which an additive is added can be used. Examples of the additive include preservatives, antifoaming agents, freezing point depressants (antifreezing agents) and the like.

The liquid 12 does not completely fill the pores of the inorganic paper sheet 10, and air or other gas may be present in the inorganic paper sheet 10. In this case, the liquid 12 evenly impregnates the entire inorganic paper sheet 10 due to the capillary phenomenon. By leaving air or the like in the inorganic paper sheet 10 in this way, it is possible to prevent the liquid 12 from interposing between the inorganic paper sheet 10 and the bag body 11, so that the partition member 3 presses and holds between the power storage elements 1. By receiving the oppressive force at the time of being applied by the inorganic paper sheet 10, it is possible to prevent the internal pressure of the bag body 11 from excessively increasing regardless of the temperature increase.

The holding member 4 holds a plurality of power storage elements 2, a plurality of partition members 3, and a cooling member 6. The holding member 4 may have, for example, a rack shape, a frame shape, a box shape, or the like.

It is preferable that the holding member 4 arranges a plurality of power storage elements 2 so that the long side surfaces face each other, and arranges the partition member 3 between the long side surfaces of the power storage element 2. Further, it is preferable that the holding member 4 holds the cooling member 6 so as to be adjacent to a surface different from the surface (long side surface) facing the partition member of the power storage element 2.

It is preferable that the holding member 4 presses and holds the power storage element 2 and the partition member 3 in the arrangement direction. As a configuration for pressing and holding the power storage element 2 and the partition member 3, for example, as shown in the figure, a structure in which a compression plate 16 for pressing the power storage element 2 is pressed by a pushing bolt 17, a configuration in which an elastic member such as a spring is used, and the like are used. Can be adopted. By pressing and holding the power storage element 2 and the partition member 3 in this way, a dead space is not formed between the power storage element 2 and the partition member 3, and the energy density of the power storage module 1 can be increased and individually. Since it is not necessary to hold the power storage element 2 and the partition member 3, the configuration of the holding member 4 can be simplified.

As the lower limit of the pressing force of the holding member 4 (the value obtained by dividing the pressing force by the area of the case 7 of the power storage element 2), 50 kPa is preferable, and 100 kPa is more preferable. On the contrary, as the upper limit of the pressing force of the holding member 4, 400 kPa is preferable, and 300 kPa is more preferable. By setting the compression force of the holding member 4 to the lower limit or higher, the power storage element 2 and the partition member 3 can be reliably held. Further, by setting the compression force of the holding member 4 to the upper limit or less, it is possible to prevent a decrease in energy density due to an increase in the thickness of the case 7 of the power storage element 2.

The bus bar 5 may connect the positive electrode external terminal 8 of the power storage element 2 and the negative electrode external terminal 9 of the adjacent power storage element 2, and may electrically connect a plurality of power storage elements 2 in series. The bus bar 5 may connect a plurality of power storage elements 2 in parallel.

The cooling member 6 is arranged so as to be adjacent to the plurality of power storage elements 2 so as to extend in the arrangement direction of the plurality of power storage elements 2, and takes heat from each power storage element 2. The cooling member 6 cools the power storage element 2 and suppresses heat accumulation in the power storage element 2 in a normal use state.

The cooling member 6 may be an air-cooled type, but from the viewpoint of enhancing the cooling effect, it is preferable that the cooling member 6 is configured so that a refrigerant such as cooling water can pass through the inside.

A heat transfer sheet formed of, for example, a resin, a gel, or the like may be arranged between the cooling member 6 and each power storage element 2 in order to prevent the formation of gaps and improve the efficiency of heat conduction.

As described above, in the power storage module 1, the partition member 3 that takes heat as heat of vaporization by accommodating the inorganic paper sheet 10 in the bag 11 and impregnating the inorganic paper sheet 10 with a liquid is a power storage element. It is placed between two. Therefore, even if one of the power storage elements 2 becomes overheated for some reason, although it is not in a normal use state, the partition member 3 conducts heat conduction from the overheated power storage element 2 to the adjacent power storage element 2. Since it can be suppressed, it is possible to prevent a chain of superheated states between the power storage elements 2.

FIG. 3 shows a storage pack including the power storage module 1 of FIG. The power storage pack of FIG. 3 includes a plurality of power storage modules 1, an isolation member 18 arranged between adjacent power storage modules 1, and a holder (pack case) 19 for holding the plurality of power storage modules 1 and the isolation member 18. To be equipped.

The isolation member 18 has an inorganic paper sheet mainly composed of inorganic fibers and a bag body for accommodating the inorganic paper sheet in the internal space, and the internal space of the bag body is depressurized. The inorganic paper sheet and the bag body of the isolation member 18 can be the same as the inorganic paper sheet 10 and the bag body 11 of the partition member 3. That is, the isolation member 18 is configured in the same manner as the partition member 3 except that the plane dimensions are different.

The holder 19 may be a frame body for fixing the plurality of power storage modules 1 and the isolation member 18. For example, it is preferable to use a solid box body for accommodating the power storage module 1 and the isolation member 18. The holder 19 may be configured to have a base member for holding the power storage module 1 and the isolation member 18, and a cover for covering the power storage module 1, the isolation member 18, and the base member. When the holder 19 has a base member and a cover, the cover may be integrally formed with, for example, a vehicle equipped with a storage pack.

[Other embodiments]
The embodiments do not limit the configuration of the present invention. Accordingly, the embodiments may be omitted, replaced or added to components of each of the embodiments based on the description of the present specification and common general knowledge, all of which are construed as belonging to the scope of the present invention. Should be.

In the power storage module, the cooling member is optional. Further, the cooling member may be integrated with the holding member.

In the power storage module, the bag body does not have to have a metal layer as long as sufficient gas barrier properties can be ensured.

The power storage module and the power storage pack according to the present invention can be particularly preferably used as a power source for a vehicle. Further, the power storage module and the power storage pack according to the present invention include a power storage system (large-scale power storage system, small-scale household power storage system), a distributed power supply system combined with natural energy such as solar energy and wind power, and a power supply system for railways. It can also be suitably used for industrial applications such as a power supply system for an unmanned carrier (AGV).

1 Power storage module 2 Power storage element 3 Partition member 4 Holding member 5 Bus bar 6 Cooling member 7 Case 8 Positive electrode external terminal 9 Negative electrode external terminal 10 Inorganic paper sheet 11 Bag body 12 Liquid 13 Metal layer 14 Coating layer 15 Adhesive layer 16 Compression plate 17 Pushing Bolt 18 Isolation member 19 Holder

Claims (3)

It is a power storage module for vehicles.
A plurality of power storage elements, a partition member arranged between the power storage elements, and a bus bar for electrically connecting the plurality of power storage elements above the plurality of power storage elements are provided.
The partition member has an inorganic paper sheet mainly composed of inorganic fibers, a bag body for accommodating the inorganic paper sheet in an internal space, and a liquid containing water as a main component and impregnating the inorganic paper sheet.
The bag body is configured to be released by an increase in internal pressure to release water vapor inside to the outside .
The inorganic paper sheet has a water content of 30% by volume or more and 80% by volume or less and a thickness of 0.2 mm or more and 1.0 mm or less.
The porosity of the inorganic paper sheet under atmospheric pressure is 70% or more and 97% or less.
The porosity of the inorganic paper sheet when a pressure of 200 kPa is applied to the power storage element is 45% or more and 80% or less.
Power storage module. The power storage element is formed in a rectangular parallelepiped shape.
The power storage module according to claim 1, wherein the partition member is pressed and held between the long side surfaces of the power storage element. The plurality of power storage modules according to claim 1 or 2 ,
A holder that holds the plurality of power storage modules,
A storage pack equipped with.

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