JP2019091581A - Electrode body and power storage element - Google Patents

Abstract

To provide an electrode body in which an electrode plate does not easily protrude from a separator and also to provide a power storage element.SOLUTION: An electrode body according to one aspect of the present invention includes an electrode plate; and a bag-like separator in which the electrode plate is housed. The bag-like separator has a plurality of welded parts with welding separator sheets welded together. The plurality of welded parts are separated from one another, form a plurality of rows along the outer edge of the bag-like separator and are arranged so that at least one welded part exists on the straight line across the rows of the welded parts in a direction perpendicular to the outer edge of the bag-like separator.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrode body and a storage element.

  BACKGROUND ART A chargeable / dischargeable storage element (secondary battery) is used in various devices such as mobile phones and electric vehicles. In recent years, with the increase in output and performance of these devices, storage devices having smaller sizes and larger electric capacities (large energy density) have been required.

  As a storage element, an electrode formed by alternately laminating a positive electrode plate having a positive electrode active material layer formed on the surface and a negative electrode plate having a negative electrode active material layer formed on the surface via a separator having electrical insulation Those equipped with a body are widely used. In order to increase the electrical capacity per unit volume with such a storage element, it is effective to make the separator thinner. Therefore, a storage element in which a separator is formed of a porous resin film has been put to practical use.

  In the electrode body, when the positive electrode plate, the negative electrode plate, and the separator are displaced from one another, the positive electrode plate and the negative electrode plate may protrude from the separator and come into contact with each other to cause a short circuit. In addition, in a storage element using a resin film as a separator, the positive electrode plate and the negative electrode plate may come in contact with each other at a peripheral portion to cause a short circuit by contraction of the separator due to temperature rise.

  Therefore, the positive electrode plate or the negative electrode plate can be formed by bonding two separators along the outer edge to form a bag, and using the bagged electrode plate in which the positive electrode plate or the negative electrode plate is inserted in the separator bag. There is known a technique for preventing the occurrence of a short circuit from protruding from the separator. For example, in Japanese Patent Application Laid-Open No. 2014-211974, a separator shrinks by intermittently joining two separators to form a bag body so that an adhesion part and a non-adhesion part are alternately formed. And a technique for discharging the gas generated on the surface of the electrode from the non-adhered portion to the outside.

JP, 2014-211974, A

  When a separator formed of the resin film is welded, the strength is often reduced and it is likely to break easily. When the resin film shrinks due to heat, the force may be concentrated on the welded portion of the separator to cause breakage of the separator or peeling of the welded portion. For this reason, although it is not a normal use condition, when the storage element is overheated for some reason, in the electrode body using the conventional bagged electrode plate, the contraction of the separator can not be prevented and a short circuit occurs to further generate heat. I can not deny the danger of causing

  In view of the above situation, the present invention has an object to provide an electrode body and a storage element in which the electrode plate is less likely to protrude from the separator.

  An electrode body according to an aspect of the present invention made to solve the above problems includes an electrode plate and a bag-like separator for containing the electrode plate, and the bag-like separators are a plurality of separator sheets welded together. The plurality of welds spaced apart from one another to form a plurality of rows along the outer edge of the bag-like separator, and in a direction perpendicular to the outer edge of the bag-like separator At least one said weld is arranged in a straight line across the row.

  In the electrode body according to one aspect of the present invention, it is difficult for the electrode plate to protrude from the separator.

It is a typical sectional view showing an electricity storage element of one embodiment of the present invention. It is a schematic plan view which shows the bagging electrode plate in the electrode body of the electrical storage element of FIG. It is a schematic plan view which shows the bagged electrode plate in the electrode body of embodiment different from FIG. 2 of this invention. It is a schematic plan view which shows the bagged electrode plate in the electrode body of embodiment different from FIG.2 and FIG.3 of this invention. It is a schematic plan view which shows the bagged electrode plate in the electrode body of embodiment different from FIG. 2 thru | or 4 of this invention.

  One aspect of the bagged electrode plate according to the present invention includes an electrode plate and a bag-like separator for housing the electrode plate, and the bag-like separator has a plurality of welded portions in which separator sheets are welded to each other. The plurality of welds are spaced apart from one another to form a plurality of rows along the outer edge of the bag-like separator, and on a straight line crossing the rows of welds in a direction perpendicular to the outer edge of the bag-like separator. At least one said weld is arranged to be present.

  The electrode assembly is arranged such that a plurality of welds of the bag-like separator form a row parallel to the side edge of the electrode plate, whereby the electrolyte is removed from the non-welds between the plurality of welds. Can be supplied to the electrode plate, which facilitates manufacture of the storage element. Further, in the electrode body, when the plurality of welded portions of the bag-like separator form a plurality of rows separated from each other, the welded portion by the edge of the electrode plate when the separator sheet shrinks due to heat. The electrode plate can not protrude from the bag-like separator unless peeling is performed a plurality of times. When peeling the bonded portion between the separator sheets, a large force is required at the start of peeling, while the force necessary for continuously expanding the peel is relatively small, so multiple welds are arranged. In the electrode body, the bag-like separator is difficult to be opened, and the electrode plate does not easily protrude from the separator sheet. In the electrode assembly, the plurality of welds are arranged such that at least one weld is present on a straight line crossing the row of welds in a direction perpendicular to the outer edge of the electrode plate. Since the entry of foreign matter from the non-welded portion can be suppressed, the internal short circuit due to electrodeposition can be prevented.

  In the electrode body, it is preferable that an average interval of the welds in the row is 0.5 times or more and 3 times or less of an average width of the welds in a direction perpendicular to the outer edge of the electrode plate. According to this configuration, by reducing the area occupied by the row of welds, the difference in area between the electrode plate and the separator sheet can be reduced, and the energy density of the electrode body and hence the storage element can be increased. In addition, since the possibility that at least one of the welds also exists on a straight line crossing the row of welds in a direction inclined with respect to the outer edge of the electrode plate is increased, the electrodeposition due to the intrusion of foreign matter is further enhanced. It can be reliably prevented.

  In the electrode body, it is preferable that an average length in a direction along the rows of the welded portion is 0.5 times or more and 3 times or less of a center distance between adjacent rows. This configuration also increases the possibility of the presence of at least one weld on a straight line crossing the row of welds in a direction inclined with respect to the outer edge of the electrode plate. Analysis can be further reliably prevented.

  In the said electrode body, it is preferable that the sum total length of the non-welding part in the row of the said welding part is 30% or more and 50% or less of row length. According to this configuration, the adhesion strength per row length of the welded portion can be increased while reliably suppressing the entry of foreign matter from the non-welded portion.

  One aspect of a storage element according to the present invention includes the electrode body and a case for housing the electrode body. The said electrical storage element can prevent the excessive internal pressure rise in a case by using the said electrode body which can prevent a short circuit with an electrode plate and a negative electrode plate effectively.

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

  FIG. 1 shows a storage element according to an embodiment of the present invention. The storage element includes an electrode body 1 and a case 2 for housing the electrode body 1. In addition, in the storage element, the inside of the case 2 is filled with an electrolytic solution. The electrode assembly 1 is an embodiment of the electrode assembly according to the present invention.

  The electrode body 1 includes a plurality of bagged electrode plates 6 each having a positive electrode plate (positive electrode plate) 3 and a bag-like separator 5 having a pair of separator sheets 4 covering the front and back surfaces of the positive electrode plate 3 (see FIG. 2) And a plurality of negative electrode plates (negative electrode plates) 7 alternately stacked with the plurality of bagged electrode plates 6.

  The bag-like separator 5 of the bagging electrode plate 6 is formed in a bag shape by having a plurality of welded portions 8 in which the pair of separator sheets 4 are welded to each other on the outside of the positive electrode plate 3 in plan view. .

  The bag-like separator 5 may be formed by providing the welding portion 8 at the peripheral edge of the two stacked separator sheets 4, and by folding one sheet in two, the two separator sheets 4 at the folding line are formed. And the welding portion 8 may be provided at the peripheral edge portion other than the folding line. In the range in which the form of the bag-like separator 5 can be maintained, there may be a portion where the welding portion 8 is not formed in a portion other than the folding line in the peripheral portion of the separator sheet 4.

  In the bag-like separator 5, the plurality of welded portions 8 are arranged to be separated from each other to form non-welded portions in which the separator sheets 4 are not welded to each other. Since the electrolytic solution can be supplied to the positive electrode plate 3 from the non-welded part between the welded parts 8 at the time of manufacture of the electric storage element, the manufacture of the electric storage element is easy.

  Further, the plurality of welded portions 8 are arranged to form a plurality of rows (two rows in the present embodiment) parallel to the side edge of the positive electrode plate 3. Thus, the bagged electrode plate 6 can suppress the positive electrode plate 3 from protruding from the separator sheet 4 even when the separator sheet 4 is shrunk by heat.

  Describing in more detail, when the separator sheet 4 contracts, a tension that acts so as to peel off between the pair of separator sheets 4 on the end face of the positive electrode plate 3 is generated. Such peeling of the welded portion 8 requires a relatively large force at the start of peeling, whereas only a smaller force is required to continuously expand the peeling. For this reason, a plurality of welded portions 8 are spaced apart in the direction in which peeling progresses, that is, in the direction perpendicular to the side edge of positive electrode plate 3, and after peeling of one welded portion 8 is completed, relatively again. Peeling off of the next weld 8 is not started unless a large tension acts. Therefore, by arranging the plurality of welded portions 8 in multiple rows, it is possible to suppress the bag-like separator 5 from being opened and the positive electrode plate 3 from protruding from the separator sheet 4.

  Furthermore, the plurality of welds 8 are arranged such that at least one weld 8 is present on a straight line that intersects the row of welds 8 in a direction perpendicular to the outer edge of the positive electrode plate 3. Thus, foreign matter can be prevented from entering the inside of the bag-like separator 5 from the non-welded portion between the welded portions 8, and internal short circuit due to electrodeposition can be prevented.

  Hereinafter, in order to deepen the understanding of the storage element, a non-limiting exemplary configuration of each component will be described in detail.

  The positive electrode plate 3 has a conductive foil- or sheet-like positive electrode current collector 9 and a positive electrode active material layer 10 laminated on both surfaces of the positive electrode current collector 9. More specifically, the positive electrode plate 3 has a rectangular electrode portion 11 in plan view (the stacking direction of the bagged electrode plate 6 and the negative electrode plate 7) in which the positive electrode active material layer 10 is stacked on both surfaces of the positive electrode current collector 9 And a tab 12 projecting from the first side of the electrode portion 11.

  As a material of the positive electrode current collector 9, a metal such as aluminum, copper, iron, nickel or an alloy thereof is used. Among these, aluminum, an aluminum alloy, copper and a copper alloy are preferable, and aluminum and an aluminum alloy are more preferable, from the balance of the height of conductivity and the cost.

  The positive electrode active material layer of the positive electrode plate is a porous layer formed of a so-called mixture containing a positive electrode active material. Moreover, the composite material which forms a positive electrode active material layer contains arbitrary components, such as a electrically conductive agent, a binder (binder), a thickener, a filler, as needed.

As the positive electrode active material, for example, _Li x _MO y composite oxide (M is at least representative of a kind of transition metal) represented by _{(Li x CoO 2, Li x} NiO 2, Li x Mn 2 O 4, Li x 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 Me _{x (XO y)} polyanionic compound represented by _{z (LiFePO 4,} LiMnPO 4, etc.). The elements or polyanions in these compounds may be partially substituted by other element or anion species.

  The bag-shaped separator 5 is formed by connecting a pair of separator sheets 4 in a bag shape by the welding portion 8. The separator sheet 4 separates the positive electrode plate 3 and the negative electrode plate 7, holds the electrolytic solution between the positive electrode plate 3 and the negative electrode plate 7, and delivers ions between the positive electrode plate 3 and the negative electrode plate 7. Mediate.

  The welded portion 8 of the bag-like separator 5 is formed by pressing the pair of separator sheets 4 with a heat indenter, an ultrasonic indenter, or the like to melt and bond the separator sheets 4 to each other. Alternatively, an adhesive may be applied to one of the pair of separator sheets 4 so as to have the shape of the welded portion 8, and the other separator sheet 4 may be overlapped and pressed.

  The lower limit of the length from the outer edge of the separator sheet 4 to the outer edge of the positive electrode plate 3 is preferably 0.5 mm, more preferably 1.0 mm. On the other hand, the upper limit of the length from the outer edge of the separator sheet 4 to the outer edge of the positive electrode plate 3 is preferably 2.0 mm, more preferably 1.5 mm. By setting the length from the outer edge of the separator sheet 4 to the outer edge of the positive electrode plate 3 as the lower limit or more, a plurality of welded portions can be provided. By setting the length from the outer edge of separator sheet 4 to the outer edge of positive electrode plate 3 or less to the upper limit or less, the margin portion of the separator can be made smaller, and the energy density of the storage element can be increased.

  It is preferable that each welding part 8 is a planar view rectangular shape, as shown in FIG. According to this configuration, the plurality of welded portions 8 can be arranged at a relatively small pitch. Further, each welding portion 8 more preferably has a rectangular shape in which a pair of opposing sides are parallel to the outer edge of the positive electrode plate 3. As a result, the average width of the welded portion 8 in the direction perpendicular to the outer edge of the positive electrode plate 3 can be increased, so that the bonding strength per length of the row of the welded portion 8 can be easily increased.

  The lower limit of the average distance (gap) between adjacent welds 8 in the row is preferably 0.5 times the average width of the welds 8 in the direction perpendicular to the outer edge of the positive electrode plate 3, and more preferably 1 time. On the other hand, the upper limit of the average distance of the welds 8 is preferably three times the average width of the welds 8 in the direction perpendicular to the outer edge of the positive electrode plate 3, and more preferably twice. By setting the average distance between the welds 8 to the above lower limit or more, the welds 8 can be separated reliably to improve the peeling start stress of the welds 8. Therefore, the protrusion of the positive electrode plate 3 from the separator sheet 4 is made more reliable. Can be prevented. Further, by setting the average distance between the welded portions 8 to the upper limit or less, it is possible to more reliably prevent foreign matter from entering the bag from the non-welded portion between the welded portions 8.

  The lower limit of the average length in the direction parallel to the outer edge of the positive electrode plate 3 of the welded portion 8 is preferably 0.5 times the average width in the direction perpendicular to the outer edge of the positive electrode plate 3 of the welded portion 8. Is more preferred. On the other hand, the upper limit of the average length in the direction parallel to the outer edge of the positive electrode plate 3 of the welded portion 8 is preferably 10 times the average width in the direction perpendicular to the outer edge of the positive electrode plate 3 of the welded portion 8 Preferably, 1.2 times is more preferable. By setting the average length in the direction parallel to the outer edge of the positive electrode plate 3 of the welded portion 8 to the above lower limit or more, the peel strength of the welded portion 8 alone can be sufficiently increased. In addition, by setting the average length in a direction parallel to the outer edge of positive electrode plate 3 of welds 8 to be the upper limit or less, the number of welds 8 in the row is increased, whereby separator sheet 4 shrinks unevenly. In the case where tension acts diagonally due to a cause or the like, it is possible to suppress the peeling of the welding portion 8 from proceeding along the outer edge of the positive electrode plate 3.

  The lower limit of the average width in the direction perpendicular to the outer edge of the positive electrode plate 3 of the welded portion 8 is preferably 0.05 mm, and more preferably 0.1 mm. On the other hand, as an upper limit of the average width of the welding part 8 in the direction perpendicular to the outer edge of the positive electrode plate 3, 1.5 mm is preferable, and 1.0 mm is more preferable. By setting the average width in the direction perpendicular to the outer edge of the positive electrode plate 3 of the welded portion 8 to be the lower limit or more, the separator sheets 4 can be reliably joined. Further, by setting the average width in the direction perpendicular to the outer edge of positive electrode plate 3 of welded portion 8 to the upper limit or less, the dimensional difference between separator sheet 4 and positive electrode plate 3 is reduced to reduce electrode assembly 1 and thus the storage element. The energy density can be increased, and the peel strength can be sufficiently increased by increasing the number of rows of welds 8 per width.

  As a minimum of the total length of the non-welding part in the line of welding part 8, 30% of the line length of welding part 8 is preferred, and 35% is more preferred. On the other hand, as an upper limit of the total length of the non-welded portions in the row of the welded portions 8, 50% of the row length of the welded portions 8 is preferable, and 45% is more preferable. By setting the total length of the non-welded portions in the row of the welded portions 8 to the above lower limit or more, separation between the welded portions 8 is ensured, and supply of the electrolytic solution from the non-welded portion to the positive electrode plate 3 is easy Become. Further, by setting the total length of non-welded portions in the row of welded portions 8 equal to or less than the upper limit, foreign matter moves in a direction in which the foreign matter is inclined with respect to the outer edge of positive electrode plate 3 even when the number of rows of welded portions 8 is small. In addition, it is possible to prevent the internal short circuit due to the electrodeposition of the electrode body 1 by suppressing the penetration into the inside of the bag-like separator 5 by meandering so as to sew between the welded portions 8.

  As a minimum of the average interval between the lines of welding part 8, 0.1 mm is preferred and 0.2 mm is more preferred. On the other hand, as an upper limit of the average space | interval between the lines of the welding part 8, 1.0 mm is preferable and 0.5 mm is more preferable. By setting the average distance between the rows of welds 8 to the above lower limit or more, the rows of welds 8 can be reliably separated and the peeling start stress of welds 8 in the second row can be improved. Protrusion from the separator sheet 4 can be prevented more reliably. Further, by setting the average distance between the rows of welded portions 8 equal to or less than the upper limit, the difference in size between positive electrode plate 3 and separator sheet 4 is reduced, and the energy density of electrode body 1 and thus the storage element is increased. Can.

  The lower limit of the average distance between the welded portion 8 and the outer edge of the positive electrode plate 3 is preferably 0.1 mm, and more preferably 0.2 mm. On the other hand, as an upper limit of the average space | interval of the welding part 8 and the outer edge of the positive electrode plate 3, 1.0 mm is preferable and 0.8 mm is more preferable. By setting the average distance between the welded portion 8 and the outer edge of the positive electrode plate 3 to the lower limit or more, welding between the pair of separator sheets 4 can be made reliable. Further, by setting the average distance between the welded portion 8 and the outer edge of the positive electrode plate 3 below the upper limit, the dimensional difference between the positive electrode plate 3 and the separator sheet 4 is reduced, and the energy density of the electrode body 1 and thus the storage element Of the positive electrode plate 3 can be prevented.

  As an upper limit of the average space | interval of the outer edge of the separator sheet 4, and the welding part 8, 1.0 mm is preferable. By setting the average distance between the outer edge of separator sheet 4 and welded portion 8 below the upper limit, the difference in size between positive electrode plate 3 and separator sheet 4 is reduced to increase the energy density of electrode assembly 1 and thus the storage element. While being able to be set, the protrusion from the separator sheet 4 of the positive electrode plate 3 can be more reliably prevented. On the other hand, the lower limit of the average distance between the outer edge of the separator sheet 4 and the welded portion 8 is preferably 0 mm. That is, it is preferable that the welded portion 8 be disposed at the outer edge of the separator sheet 4. By arranging the welding portion 8 on the outer edge of the separator 4, the welding width of the separators can be narrowed, and the size of the electrode plate can be increased. When the separator sheet 4 is cut, the welded portion 8 can be provided on the outer edge of the separator sheet 4 by cutting so as to pass through the welded portion.

  The separator sheet 4 for forming the bag-like separator 5 is formed of the porous sheet-like resin layer 13 and an acid resistant layer laminated on the surface of the resin layer 13 on the side facing the positive electrode plate 3 (inner side of the bag-like separator 5). A heat resistant layer 14 and a weldable adhesive layer 15 laminated on the surface of the oxidation resistant or heat resistant layer 14.

  The main component of the resin layer 13 of the separator sheet 4 is, for example, a polyolefin derivative such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, chlorinated polyethylene, etc. A polyolefin such as ethylene-propylene copolymer, or a polyester such as polyethylene terephthalate or copolymer polyester can be employed. Among them, polyethylene and polypropylene, which are excellent in electrolytic solution resistance and durability, are preferably used as the main component of the resin layer 13.

  The oxidation resistant layer or the heat resistant layer 14 of the separator sheet 4 can be configured to include a large number of inorganic particles and a binder for connecting the inorganic particles. In addition, a "heat-resistant layer" means what prevents the failure | damage by the heat of the separator sheet 4, and prevents a short circuit with a positive electrode plate and a negative electrode plate more. On the other hand, “the oxidation resistant layer” means one that protects the separator sheet 4 under a high voltage environment and prevents the oxidation of the separator sheet 4. The oxidation resistant layer or the heat resistant layer 14 may be a combination of both functions.

  As a main component of the inorganic particles, for example, oxides such as alumina, silica, zirconia, titania, magnesia, ceria, yttria, zinc oxide, iron oxide, nitrides such as silicon nitride, titanium nitride, boron nitride, silicon carbide, carbonate Calcium, aluminum sulfate, boehmite, aluminum hydroxide, magnesium hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos, zeolite, silica Examples include calcium acid and magnesium silicate. Among them, as a main component of the inorganic particles of the heat-resistant layer or the oxidation resistant layer, alumina, silica and titania are particularly preferable.

  Examples of the binder of the oxidation resistant layer or the heat resistant layer 14 include acrylic resins, polyvinylidene fluoride (PVDF) resins, and aramid resins.

  When the oxidation resistant layers or heat resistant layers of the separator sheet 4 are welded to form a bag shape, or when the oxidation resistant layer or heat resistant layer of the separator sheet 4 and the resin layer of the separator sheet 4 are welded, It can be adhered by the adhesive layer 15. For example, the adhesive layer 15 can be made of a material which is melted by heating or the like to exhibit adhesiveness. Furthermore, in order not to inhibit lithium ion migration in the separator sheet 4, the adhesive layer 15 is preferably a material or a porous material that is permeable to ions. As a material of the adhesive layer 15, a thermoplastic resin can be used, and among them, polyvinylidene fluoride (PVDF) resin and acrylic polymer are suitably used.

  When the resin layers of the separator sheet 4 are welded together when forming the bag shape, the resin layer can be melted and welded by heating, and the adhesive layer 15 can be omitted.

  The negative electrode plate 7 has a conductive foil- or sheet-like negative electrode current collector 16 and a negative electrode active material layer 17 laminated on the surface of the negative electrode current collector 16. Specifically, as in the case of the positive electrode plate 3, the negative electrode plate 7 extends in a strip shape from the electrode portion in a rectangular shape in plan view, in which the negative electrode active material layer 17 is stacked on the surface of the negative electrode current collector 16. And a tab electrically connected to the electrode terminal of the storage element.

  In the electrode body 1, the electrode portion 11 of the positive electrode plate 3 is included inside the electrode portion 11 of the negative electrode plate 7 in a plan view. As a result, current (delivery of charge via ions with the positive electrode plate 3) is not concentrated on the outer edge portion of the electrode portion of the negative electrode plate 7.

  The material of the negative electrode current collector 16 of the negative electrode plate 7 is preferably copper or a copper alloy. Moreover, as a shape of the negative electrode collector 16, a foil is preferable. That is, copper foil is preferable as the negative electrode current collector 16 of the negative electrode plate 7. As a copper foil used as the negative electrode collector 16, a rolled copper foil, an electrolytic copper foil, etc. are illustrated, for example.

  The negative electrode active material layer 17 is a porous layer formed of a so-called mixture containing a negative electrode active material. Moreover, the composite material which forms the negative electrode active material layer 17 contains arbitrary components, such as a conductive agent, a binder (binder), a thickener, and a filler, as needed.

  As the negative electrode active material, a material capable of inserting and extracting lithium ions is preferably used. Specific negative electrode active materials include, for example, metals such as lithium and lithium alloy, metal oxides, polyphosphate compounds, and carbon materials such as graphite and amorphous carbon (graphitizable carbon or non-graphitizable carbon). Etc. In the negative electrode active material layer 17, one of these compounds may be used alone, or two or more may be mixed and used.

  The case 2 has a sealed structure so as to seal the electrode body 1 and the electrolyte. As such a case 2, for example, a flexible bag-like separator formed of a laminate sheet in which a metal foil and a resin film are joined may be used, and a rigid container made of resin or metal is used. Although it is preferable, it is preferable to use a box-shaped (rectangular parallelepiped) metal container which is excellent in strength and can reduce a dead space.

  The case 2 is provided with a positive electrode external terminal (not shown) to which the tab 12 of the positive electrode plate 3 is connected and a negative electrode external terminal (not shown) to which the tab of the negative electrode plate 7 is connected. That is, the electrode assembly 1 is connected to an external circuit via the positive electrode external terminal and the negative electrode external terminal.

As an electrolytic solution to be enclosed in the case 2 together with the electrode body, a known electrolytic solution generally used for a storage element can be used. For example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, etc. A solution in which lithium hexafluorophosphate (LiPF ₆ ) or the like is dissolved in a solvent containing a linear carbonate such as methyl carbonate can be used.

  FIG. 3 shows a bagged electrode plate 6a of an electrode assembly according to an embodiment different from FIG. 2 of the present invention. This bagging electrode plate 6a can be used for the electrode body 1 and the storage element of FIG. 1 in place of the bagging electrode plate 6 of FIG.

  The bagged electrode plate 6 a includes a positive electrode plate 3 and a plurality of bag-like separators 5 a having a pair of separator sheets 4 covering the front and back surfaces of the positive electrode plate 3. The bag-like separator 5a of the bagging electrode plate 6a has a plurality of welded portions 8a in which the pair of separator sheets 4 are welded to each other on the outside of the positive electrode plate 3 in a plan view.

  The configuration of the bagged electrode plate 6a of FIG. 3 is the same as the configuration of the bagged electrode plate 6 of FIG. 2 except that the planar patterns of the plurality of welded portions 8a of the bag-like separator 5a are different. Therefore, in the bagging electrode plate 6a of FIG. 3, the same components as those of the bagging electrode plate 6 of FIG.

  In the present embodiment, the plurality of welded portions 8 a of the bag-like separator 5 a are separated from each other to form non-welded portions in which the separator sheets 4 are not welded therebetween, and three welded portions are parallel to the side edge of the positive electrode plate 3. Arranged to form a row.

  Each welding portion 8 a of the bag-like separator 5 a is formed in a rhombus whose diagonal is parallel or perpendicular to the side edge of the positive electrode plate 3. The plurality of welds 8a are shifted by 1⁄2 pitch so that the positions of welds 8a alternate between adjacent rows, and between adjacent rows in a view along the side edge of positive electrode plate 3 Are arranged to overlap.

  In the present embodiment, when peeling of the welds 8a in the second and subsequent rows is started, the welds in the immediately preceding row are not completely peeled off, but the tension of the separator sheet 4 is shared. Peeling is difficult to start. For this reason, it is possible to suppress the bag-shaped separator 5 from being opened and the positive electrode plate 3 from protruding from the separator sheet 4 in the bagged electrode plate 6 a in the present embodiment.

  FIG. 4 shows a bagged electrode plate 6b of an electrode assembly according to an embodiment different from FIG. 2 of the present invention. This bagged electrode plate 6b can also be used for the electrode body 1 and the storage element of FIG. 1 in place of the bagged electrode plate 6 of FIG.

  The bagged electrode plate 6 b has a positive electrode plate 3 and a plurality of bag-like separators 5 b having a pair of separator sheets 4 covering the front and back surfaces of the positive electrode plate 3. The bag-like separator 5b of the bagging electrode plate 6b has a plurality of welded portions 8b in which the pair of separator sheets 4 are welded to each other on the outside of the positive electrode plate 3 in a plan view.

  The configuration of the bagged electrode plate 6b of FIG. 4 is the same as the configuration of the bagged electrode plate 6 of FIG. 2 except that the planar patterns of the plurality of welded portions 8b of the bag-like separator 5b are different. For this reason, in the bagging electrode plate 6b of FIG. 4, the same components as those of the bagging electrode plate 6 of FIG.

  In the present embodiment, the plurality of welded portions 8 b of the bag-like separator 5 b are separated from each other to form non-welded portions in which the separator sheets 4 are not welded therebetween, and two welded portions parallel to the side edge of the positive electrode plate 3. Arranged to form a row.

  Each welding portion 8 b of the bag-like separator 5 b is formed in an isosceles triangle shape having a base parallel to the side edge of the positive electrode plate 3 on the opposite side to the other row. The positions of the plurality of welded portions 8b are shifted by 1⁄2 pitch so that the positions of the welded portions 8b alternate between adjacent rows, and adjacent rows in a direction view along the side edge of the positive electrode plate 3 It is arranged to overlap.

  FIG. 5 shows a bagged electrode plate 6c of an electrode assembly according to an embodiment different from FIG. 2 of the present invention. This bagged electrode plate 6c can also be used for the electrode body 1 and the storage element of FIG. 1 in place of the bagged electrode plate 6 of FIG.

  The bagged electrode plate 6 c includes a positive electrode plate 3 and a plurality of bag-like separators 5 c having a pair of separator sheets 4 covering the front and back surfaces of the positive electrode plate 3. The bag-like separator 5c of the bagging electrode plate 6c has a plurality of welded portions 8c in which the pair of separator sheets 4 are welded to each other on the outside of the positive electrode plate 3 in a plan view.

  The configuration of the bagged electrode plate 6c of FIG. 5 is the same as the configuration of the bagged electrode plate 6 of FIG. 2 except that the planar patterns of the plurality of welded portions 8c of the bag-like separator 5c are different. Therefore, in the bagging electrode plate 6c of FIG. 5, the same components as those of the bagging electrode plate 6 of FIG.

  In the present embodiment, the plurality of welded portions 8c of the bag-like separator 5c are separated from each other to form non-welded portions in which the separator sheets 4 are not welded therebetween, and two welded portions parallel to the side edge of the positive electrode plate 3 are formed. Arranged to form a row.

  The welded portion 8c of the bag-like separator 5c is formed in a linear shape of a fixed length inclined at a fixed angle with respect to the side edge of the positive electrode plate 3, and the direction of inclination is opposite in each row. The positions of the plurality of welded portions 8c are shifted by 1⁄2 pitch so that the positions of the welded portions 8c are alternated between adjacent rows, and adjacent rows in a direction view along the side edge of the positive electrode plate 3 It is arranged to overlap.

Other Embodiments
The embodiment does not limit the configuration of the present invention. Therefore, the embodiment can omit, substitute, or add the components of each part of the embodiment based on the description of the present specification and common technical knowledge, and all of them can be construed as belonging to the scope of the present invention. It should.

  In the electrode body plate according to the present invention, the planar shape of each welded portion is not limited to the shape of the above embodiment, and may be any shape such as circular, star, V-shape, T-shape, etc. Can.

  In the electrode body according to the present invention, the oxidation resistant layer or heat resistant layer and the adhesive layer of the separator sheet can be omitted.

  The bagged electrode plate in the electrode body according to the present invention may include a negative electrode plate and a bag-like separator having a pair of separator sheets covering the front and back surfaces of the negative electrode plate. In this case, the electrode body may be one in which a plurality of bagged electrode plates and a plurality of positive electrode plates are alternately stacked. That is, as the electrode plate to be stacked with the bagged electrode plate, one having a polarity different from that of the electrode plate of the bagged electrode plate is used.

  The electrode body and the storage element according to the present invention can be particularly suitably used as a power source for a vehicle. In addition, the electrode body and the storage element according to the present invention are a storage system (large-scale storage system, household small-scale storage system), a distributed power system combined with natural energy such as sunlight or wind power, a railway power system, unmanned It can be suitably used for industrial applications such as a power supply system for a carrier vehicle (AGV).

1 electrode body 2 case 3 positive plate (electrode plate)
4 separator sheets 5, 5a, 5b, 5c bag-shaped separators 6, 6, 6b, 6c bagged electrode plate 7 negative electrode plate (electrode plate)
8, 8a, 8b, 8c Welded part 9 positive electrode current collector 10 positive electrode active material layer 11 electrode part 12 tab 13 resin layer 14 oxidation resistant or heat resistant layer 15 adhesive layer 16 negative electrode current collector 17 negative electrode active material layer

Claims (4)

An electrode plate; and a bag-like separator for housing the electrode plate,
The bag-like separator has a plurality of welded portions in which separator sheets are welded to each other,
The plurality of welds are
Spaced apart from each other,
A plurality of rows are formed along the outer edge of the bag-like separator, and at least one weld is arranged on a straight line crossing the row of welds in a direction perpendicular to the outer edge of the bag-like separator. To be
Electrode body. The electrode assembly according to claim 1, wherein an average interval of the welded portions in the row is 0.5 times or more and 3 times or less of an average width in a direction perpendicular to the outer edge of the electrode plate of the welded portion. The electrode assembly according to claim 1 or 2, wherein a total length of non-welded portions in the row of welded portions is 30% or more and 50% or less of the row length. An electrode body according to claim 1, 2 or 3;
And a case for housing the electrode body.

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