Battery using separator having conductive layer

Abstract

Provided is a storage battery comprising a positive electrode (1) having a positive electrode tab (2), a negative electrode (3) having a negative electrode tab (4), and a separator (5), the storage battery being characterized in that the separator (5) is disposed between the positive electrode (1) and the negative electrode (3), the separator (5) having an exposed portion exposed from both the electrodes, and the separator (5) comprising a base material and a conductive layer covering a part of the base material, the coating range reaches the end part of the base material adjacent to the tabs (2) or (4), (I) the conductive layer is electrically connected with the positive electrode (1), and the shortest distance between the conductive layer at the end part of the base material adjacent to the negative electrode tab (4) and the negative electrode tab (4) is more than 500 [mu] m; and / or (II) the conductive layer is electrically connected with the negative electrode (3), and the shortest distance between the conductive layer at the end part of the base material adjacent to the positive electrode tab (2) and the positive electrode tab (2) is more than 500 microns.

Description

Technical Field

[0001] This disclosure relates to a battery using a spacer with a conductive layer. Background Technology

[0002] In recent years, techniques for improving battery performance have been reported by using spacers whose surfaces are made conductive. For example, Patent Document 1 reports a technique for improving the charge acceptance and cycle life of a battery by using spacers coated with a conductive carbon material.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: International Publication No. 2015 / 171595. Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, when a conductive material is used to make the spacer, which is supposed to ensure insulation between electrodes, there are concerns about the reduction in insulation between electrodes, such as voltage resistance. Therefore, there is room for improvement in the battery design of systems that improve voltage resistance.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a high voltage-resistant battery by using a spacer having a conductive layer on a substrate.

[0009] Methods for solving problems

[0010] The aforementioned problems can be solved by the following technical means. Examples of embodiments of this disclosure are given below.

[0011] (1) A storage battery comprising a positive electrode having a positive tab, a negative electrode having a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, The conductive layer covers at least to the substrate end of the substrate adjacent to the positive or negative electrode tab, and... (I) The conductive layer is electrically connected to the positive electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the negative electrode tab and the negative electrode tab is 500 μm or more; and / or, (II) The conductive layer is electrically connected to the negative electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the positive electrode tab and the positive electrode tab is more than 500 μm.

[0012] (2) A storage battery comprising a positive electrode having a positive tab, a negative electrode having a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, (III) The conductive layer is electrically connected to the positive electrode, and the substrate end of the substrate adjacent to the negative electrode tab does not have the conductive layer; and / or, (IV) The conductive layer is electrically connected to the negative electrode, and the substrate end of the substrate adjacent to the positive electrode tab does not have the conductive layer.

[0013] (3) A storage battery comprising a positive electrode having a positive tab, a negative electrode having a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, The conductive layer covers at least to the substrate end of the substrate adjacent to the positive or negative electrode tab, and... (V) The conductive layer is electrically connected to the positive electrode, and the surface of the negative electrode tab is covered with an insulating material; and / or, (VI) The conductive layer is electrically connected to the negative electrode, and the surface of the positive electrode tab is covered with an insulating material.

[0014] (4) The storage battery according to item (1), wherein the shortest distance is less than 1500 μm.

[0015] (5) The battery according to item (1), wherein the shortest distance is 655 μm or more.

[0016] (6) The battery according to item (1), wherein the shortest distance is 950 μm or more.

[0017] (7) The storage battery according to any one of items (1) to (6), wherein the substrate is a rectangular sheet.

[0018] (8) The battery according to any one of items (1) to (7), wherein the surface resistance of the conductive layer is less than 5000Ω.

[0019] (9) The battery according to any one of items (1) to (8), wherein the conductive layer comprises a carbon material.

[0020] (10) The storage battery according to any one of items (1) to (9), wherein the substrate comprises a polyolefin.

[0021] (11) The storage battery according to any one of items (1) to (10), wherein the positive electrode tab and the negative electrode tab contain lead.

[0022] (12) The battery according to any one of items (1) to (11), wherein the positive electrode tab comprises aluminum and the negative electrode tab comprises nickel.

[0023] (13) The storage battery according to any one of items (1) to (12), wherein the storage battery is a lead-acid battery.

[0024] (14) The storage battery according to any one of items (1) to (13), wherein the storage battery is a lithium-ion battery.

[0025] Invention Effects

[0026] According to this disclosure, a high-voltage-resistant battery can be provided by using a spacer having a conductive layer on a substrate. Attached Figure Description

[0027] Figure 1 (a) shows the arrangement of spacers without conductive layers between the positive electrode and the positive electrode tab and the negative electrode and the negative electrode tab, (b) is a schematic view from the negative electrode side of these stacked bodies, and (c) is a cross-sectional view between the dashed lines ab in the side view (b).

[0028] Figure 2 (a) shows the case where the spacer is positioned between the positive and negative electrodes with the conductive layer of the spacer facing the positive electrode. (b) is a schematic view from the negative electrode side of the stacked body in which the spacer is electrically connected to the positive electrode. (c) is a cross-sectional view between the dashed lines ab.

[0029] Figure 3 (a) shows the case where the spacer is positioned between the positive and negative electrodes with the conductive layer of the spacer facing the negative electrode; (b) is a schematic view from the negative electrode side of the laminate in which the spacer is electrically connected to the negative electrode; and (c) is a cross-sectional view between the dashed lines ab.

[0030] Figure 4A(a) shows a case where the conductive layer coated on the entire surface of the spacer substrate according to an embodiment of the present invention is opposite to the positive electrode and the spacer is disposed between the positive and negative electrodes; (b) is a schematic diagram illustrating the shortest distance between the conductive layer at the end of the spacer substrate and the negative electrode tab; and (c) is a cross-sectional view between the dashed lines ab.

[0031] Figure 4B (a) shows a case where the conductive layer coated on a portion of the spacer substrate surface according to an embodiment of the present invention is opposite to the positive electrode and the spacer is disposed between the positive and negative electrodes; (b) is a schematic diagram illustrating the shortest distance between the conductive layer at the end of the spacer substrate and the negative electrode tab; and (c) is a cross-sectional view between the dashed lines ab.

[0032] Figure 5A (a) shows a case where the conductive layer coated on the entire surface of the spacer substrate in another embodiment of the present invention is opposite to the negative electrode and the spacer is disposed between the positive and negative electrodes; (b) is a schematic diagram illustrating the shortest distance between the conductive layer at the end of the spacer substrate and the positive electrode tab; and (c) is a cross-sectional view between the dashed lines ab.

[0033] Figure 5B (a) shows a case where the conductive layer coated on a portion of the spacer substrate surface in another embodiment of the present invention is opposite to the negative electrode and the spacer is disposed between the positive and negative electrodes; (b) is a schematic diagram illustrating the shortest distance between the conductive layer at the end of the spacer substrate and the positive electrode tab; and (c) is a cross-sectional view between the dashed lines ab.

[0034] Figure 6 (a) is a case in which a spacer with a conductive layer on the other side but no conductive layer at the end opposite to the negative or positive electrode tab is disposed between the positive and negative electrodes in another embodiment of the present invention; (b) is a schematic diagram of the spacer electrically connected to the positive or negative electrode but without a conductive layer in part ab; and (c) is a cross-sectional view between the dashed lines ab.

[0035] Figure 7A (a) is a case in which a spacer having a conductive layer is disposed between the positive and negative electrodes by covering the positive electrode tab with an insulating material in another embodiment of the present invention; (b) is a schematic view viewed from the negative electrode side of the laminate; and (c) is a cross-sectional view between the dashed lines ab.

[0036] Figure 7B (a) is a case in which a spacer having a conductive layer is disposed between the positive and negative electrodes by covering the negative electrode tab with an insulating material in another embodiment of the present invention; (b) is a schematic view viewed from the negative electrode side of the laminate; and (c) is a cross-sectional view between the dashed lines ab.

[0037] Figure 8(a) shows a spacer without a conductive layer arranged in stripes on at least a portion of the substrate surface of the spacer sample for withstand voltage testing between the positive and negative electrodes; (b) is a schematic view viewed from the negative electrode side of the laminate; and (c) is a cross-sectional view between the dashed lines ab.

[0038] Figure 9 (a) is a configuration diagram showing the components and their dimensions of the shortest distance between the conductive layer at the end of the spacer substrate and the negative or positive electrode tab. (b) is a schematic diagram viewed from the negative electrode side of the sample for testing. (c) is a cross-sectional view of the voltage withstand test sample in the same plane as the dashed line ab, at a right angle.

[0039] Figure 10 This is used to illustrate the differences between the various embodiments and comparative examples. Figure 9 A rough cross-sectional view of the section corresponding to the dashed line ab.

[0040] Figure 11 This is a schematic perspective view illustrating an application example of using a circular-shaped substrate in one embodiment of the present invention.

[0041] Figure 12 This is a schematic perspective view showing an application example of double-sided coating of a conductive layer on a substrate in one embodiment of the present invention. (a) shows the case where tabs are connected to the conductive layer connected to the end of the substrate, and (b) shows the case where tabs are connected to the conductive layer not connected to the end of the substrate. Detailed Implementation

[0042] Hereinafter, embodiments of the present disclosure (hereinafter referred to as "this embodiment") will be described in detail. In addition, the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of its main ideas.

[0043] Storage Batteries

[0044] The battery of this embodiment is a battery comprising a positive electrode with a positive electrode tab, a negative electrode with a negative electrode tab, and a spacer, characterized in that... The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer body comprises at least a substrate, at least a portion of which is covered by a conductive layer, and, The conductive layer covers at least to the end of the substrate adjacent to the tab, and... (I) The conductive layer is electrically connected to the positive electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the negative electrode tab and the negative electrode tab is 500 μm or more; and / or, (II) The conductive layer is electrically connected to the negative electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the positive electrode tab and the positive electrode tab is more than 500 μm.

[0045] The shortest distance mentioned in this specification refers to the shortest distance between the conductive layer and the electrode tabs whose surfaces are not insulated. In one embodiment, by satisfying (I) and / or (II) above, a high-voltage-resistant battery can be provided.

[0046] Furthermore, the substrate referred to in this specification is an insulating film with microporous structure, preferably an insulating film containing polyolefin and / or inorganic particles. The substrate of the insulating film can be a single layer or multiple layers, and can be exemplified by a substrate to which an inorganic layer composed of inorganic particles and resin binder is imparted on one or both sides of a microporous membrane containing polyolefin.

[0047] In this embodiment, even if the spacer is a layer structure of three or more layers such as substrate / conductive layer / substrate, a high voltage withstand capability can be obtained if (I) and / or (II) above are satisfied. Therefore, the spacer of this embodiment not only has a two-layer structure of substrate and conductive layer, but can also have a multi-layer structure such as substrate / conductive layer / substrate, conductive layer / substrate / conductive layer, etc., within the range of satisfying (I) and / or (II) above.

[0048] From the viewpoint of improving the withstand voltage at the electrode tip, the spacer is preferably larger than the size of the positive and negative electrodes and has an exposed portion. More preferably, the spacer is 0.5 mm or more larger than the positive and negative electrode tip portions. More preferably, the spacer is 1.0 mm or more larger than the spacer. Even more preferably, the spacer is 2.0 mm or more larger than the spacer. Particularly preferably, the spacer is 3.0 mm or more larger than the spacer.

[0049] Furthermore, the battery preferably contains an electrolyte or electrolyte solution (in the case of an all-solid-state battery). For example... Figure 1 As illustrated, when a spacer 5 without a conductive layer is disposed between the positive electrode 1 and the positive electrode tab 2 and the negative electrode 3 and the negative electrode tab 4, a high withstand voltage is observed. On the other hand, when the spacer 5 has a conductive layer 7 on its surface, and this conductive layer 7 is electrically connected to the positive electrode 1, it is considered part of the positive electrode 1, and therefore... Figure 2 As shown, the shortest distance between the conductive layer 7 and the negative electrode tab 4 becomes shorter ( Figure 2 (c)), thus reducing the withstand voltage. Therefore, by designing the battery to be spaced at a distance of more than a certain value from the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab as described in (I) above, the withstand voltage can be improved. Similarly, when the spacer 5 has a conductive layer 7 that is electrically connected to the negative electrode 3, the conductive layer 7 is considered as part of the negative electrode 3, therefore, as Figure 3 As shown, the shortest distance between the conductive layer 7 and the positive electrode tab 2 becomes shorter ( Figure 3 (c) This results in a decrease in withstand voltage. Therefore, by designing the battery such that the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab is separated by a certain value or more as described in (II) above, the withstand voltage can be improved. As mentioned above, for the specific problem that arises when a spacer with a conductive layer is used in a battery, namely the decrease in withstand voltage, the effect of improving the withstand voltage can be obtained by controlling the distance between the electrode tab and the conductive layer. Therefore, in principle, this is not limited to a specific battery; as long as a battery uses a spacer with a conductive layer, the effect of the present invention can be achieved regardless of the type of battery. Specifically, examples of batteries that can be used in this embodiment include lead-acid batteries, lithium-ion batteries, and redox flow batteries.

[0050] In the battery of this embodiment, when the conductive layer is electrically connected to the positive electrode, from the viewpoint of increasing the withstand voltage to 0.50 kV or more, the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab is preferably 500 μm or more, more preferably 600 μm or more. From the viewpoint of increasing the withstand voltage to 1.00 kV or more, the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab is preferably 655 μm or more, more preferably 700 μm or more, further preferably 800 μm or more, even more preferably 850 μm or more, and particularly preferably 900 μm or more. Furthermore, from the viewpoint of increasing the withstand voltage to 1.50 kV or more, the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab is preferably 950 μm or more, and most preferably 1000 μm or more. Figure 4A and Figure 4B As illustrated, in this embodiment, the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab refers to the shortest distance d1 between the conductive layer 7 at the end of the connecting spacer and the negative electrode tab 4. Figure 4A (b) or Figure 4B As shown in (b), by increasing the thickness of the substrate 6 or using a substrate 6 with a convex structure such as a conductive layer 7 on its surface, the shortest distance d1 can be adjusted to 500 μm or more, thereby improving the voltage resistance. Figure 4A (c) and Figure 4B In the comparison of (c), the position of the conductive layer 7 is adjusted with reference to the end of the substrate adjacent to the negative electrode tab 4, and the shortest distance d1 between the negative electrode tab 4 and the conductive layer 7 is adjusted to more than 500 μm, thereby improving the voltage resistance.

[0051] Furthermore, from the viewpoint of reducing the inter-electrode ion resistance in the battery by shortening the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab, the shortest distance between the conductive layer at the end of the substrate and the negative electrode tab is preferably 5000 μm or less, more preferably 4000 μm or less, even more preferably 3000 μm or less, even more preferably 2000 μm or less, and particularly preferably 1500 μm or less.

[0052] In the battery of this embodiment, when the conductive layer is electrically connected to the negative electrode, from the viewpoint of increasing the withstand voltage to 0.50 kV or more, the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab is preferably 500 μm or more, more preferably 600 μm or more. From the viewpoint of increasing the withstand voltage to 1.00 kV or more, the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab is preferably 655 μm or more, more preferably 700 μm or more, further preferably 800 μm or more, even more preferably 850 μm or more, and particularly preferably 900 μm or more. Furthermore, from the viewpoint of increasing the withstand voltage to 1.50 kV or more, the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab is preferably 950 μm or more, and most preferably 1000 μm or more. Figure 5A and Figure 5B As illustrated, in the embodiments of the present invention, the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab refers to the shortest distance d2 between the conductive layer 7 at the end of the connecting spacer and the positive electrode tab 2. Figure 5A (b) or Figure 5B As shown in (b), by increasing the thickness of the substrate 6 or using a substrate 6 with a convex structure such as a conductive layer 7 on its surface, the shortest distance d2 can be adjusted to 500 μm or more, thereby improving the voltage resistance. Figure 5A (c) and Figure 5B In comparison (c), the position of the conductive layer 7 is adjusted with reference to the end of the substrate adjacent to the positive electrode tab 2, and the shortest distance d2 between the positive electrode tab 2 and the conductive layer 7 is adjusted to more than 500 μm, thereby improving the voltage resistance.

[0053] Furthermore, from the viewpoint of reducing the inter-electrode ion resistance in the battery by shortening the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab, the shortest distance between the conductive layer at the end of the substrate and the positive electrode tab is preferably 5000 μm or less, more preferably 4000 μm or less, even more preferably 3000 μm or less, even more preferably 2000 μm or less, and particularly preferably 1500 μm or less.

[0054] Another embodiment of the present invention provides a storage battery comprising a positive electrode having a positive electrode tab, a negative electrode having a negative electrode tab, and a spacer, characterized in that... The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer body comprises at least a substrate, at least a portion of which is covered by a conductive layer, and, (III) The conductive layer is electrically connected to the positive electrode, and the end of the substrate adjacent to the negative electrode tab does not have the conductive layer; and / or, (IV) The conductive layer is electrically connected to the negative electrode, and the end of the substrate adjacent to the positive electrode tab does not have the conductive layer.

[0055] In another embodiment, even if the spacer is a layered structure of three or more layers such as substrate / conductive layer / substrate, a high withstand voltage can be obtained if (III) and / or (IV) above are satisfied. Therefore, the spacer in another embodiment not only has a two-layer structure of substrate and conductive layer, but can also have a multi-layer structure such as substrate / conductive layer / substrate, conductive layer / substrate / conductive layer, etc., within the range of satisfying (III) and / or (IV) above.

[0056] From the viewpoint of improving the withstand voltage at the electrode tip, the spacer is preferably larger than the size of the positive and negative electrodes and has an exposed portion. More preferably, the spacer is 0.5 mm or more larger than the positive and negative electrode tip portions. Even more preferably, the spacer is 1.0 mm or more larger than the spacer. Even more preferably, the spacer is 2.0 mm or more larger than the spacer. Particularly preferably, the spacer is 3.0 mm or more larger than the spacer.

[0057] Furthermore, in another embodiment, the battery preferably contains an electrolyte or electrolyte solution (in the case of an all-solid-state battery). For example... Figure 6 As illustrated, by designing the spacer end opposite to the negative electrode tab 4 or the positive electrode tab 2 to not have a conductive layer 7, satisfying the above (III) and / or (IV), it is possible to improve the conductivity between the conductive layer (not shown) electrically connected to the positive electrode and the negative electrode tab, or the conductivity between the conductive layer electrically connected to the negative electrode (…). Figure 6 (b) The withstand voltage between the positive electrode tab and the positive electrode tab. Figure 6In this design, the end of the spacer opposite to the negative electrode tab 4 or the positive electrode tab 2 is referred to as part ab. From the viewpoint of improving withstand voltage, it is preferable that the conductive layer is not provided for at least 500 μm inward from the end of the spacer opposite to the negative electrode tab or the positive electrode tab toward the inner side of the surface, more preferably for at least 600 μm, even more preferably for at least 700 μm, even more preferably for at least 800 μm, particularly preferably for at least 900 μm, and from the viewpoint of improving withstand voltage to 1.50 kV or higher, it is most preferable that the conductive layer is not provided for at least 1.00 mm inward from the end of the spacer opposite to the negative electrode tab or the positive electrode tab toward the inner side of the surface. As described above, regarding the unique problem of reduced voltage withstand when using spacers with conductive layers in a battery, the effect of increasing voltage withstand is achieved by not providing a conductive layer at the end of the spacer adjacent to the electrode tabs. Therefore, in principle, this effect is not limited to specific batteries; it applies to any type of battery that uses spacers with conductive layers. Specifically, examples of batteries that can be implemented as another embodiment include lead-acid batteries, lithium-ion batteries, and redox flow batteries.

[0058] Furthermore, another embodiment of the present invention provides a battery comprising a positive electrode having a positive electrode tab, a negative electrode having a negative electrode tab, and a spacer, characterized in that... The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer body comprises at least a substrate, at least a portion of which is covered by a conductive layer, and, The conductive layer covers at least to the end of the substrate adjacent to the tab, and, (V) The conductive layer is electrically connected to the positive electrode, and the surface of the negative electrode tab is covered with an insulating material; and / or, (VI) The conductive layer is electrically connected to the negative electrode, and the surface of the positive electrode tab is covered with an insulating material.

[0059] In another embodiment, even if the spacer is a layered structure of three or more layers such as substrate / conductive layer / substrate, a high voltage withstand capability can be obtained if (V) and / or (VI) are satisfied above. Therefore, the spacer in another embodiment not only has a two-layer structure of substrate and conductive layer, but can also have a multi-layer structure such as substrate / conductive layer / substrate, conductive layer / substrate / conductive layer, etc., within the range of (V) and / or (VI) above.

[0060] From the viewpoint of improving the withstand voltage at the electrode tip, the spacer is preferably larger than the size of the positive and negative electrodes and has an exposed portion. More preferably, the spacer is 0.5 mm or more larger than the positive and negative electrode tip portions. Even more preferably, the spacer is 1.0 mm or more larger than the spacer. Even more preferably, the spacer is 2.0 mm or more larger than the spacer. Particularly preferably, the spacer is 3.0 mm or more larger than the spacer.

[0061] Furthermore, in another embodiment, the battery preferably contains an electrolyte or electrolyte solution (in the case of an all-solid-state battery). For example... Figure 7A and Figure 7B As shown in the example, by covering the negative electrode tab 4 or the positive electrode tab 2 with insulating material 8 ( Figure 7A (a) ~ Figure 7A (c) or Figure 7B (a) ~ Figure 7B (c) can suppress short circuits between the conductive layer 7 of the spacer 5 and the positive electrode tab 2, or between the conductive layer 7 of the spacer 5 and the negative electrode tab 4. The entire surface of the negative or positive electrode tab is covered with insulating material, thereby improving voltage withstand capability.

[0062] Furthermore, when a portion of the negative electrode tab is covered with an insulating material, the shortest distance between the conductive layer at the end of the spacer and the negative electrode tab not covered by the insulating material is preferably 500 μm or more, more preferably 600 μm or more, even more preferably 655 μm or more, even more preferably 700 μm or more, even more preferably 800 μm or more, even more preferably 850 μm or more, particularly preferably 900 μm or more, and most preferably 1000 μm or more.

[0063] Furthermore, when a portion of the positive electrode tab is covered with an insulating material, the shortest distance between the conductive layer at the end of the spacer and the portion of the positive electrode tab not covered by the insulating material is preferably 500 μm or more, more preferably 600 μm or more, even more preferably 655 μm or more, even more preferably 700 μm or more, even more preferably 800 μm or more, even more preferably 850 μm or more, particularly preferably 900 μm or more, and most preferably 1000 μm or more.

[0064] As for the insulating material covering the electrode tabs, there are no particular limitations as long as the material can ensure insulation. However, as specific examples, epoxy resin, silicone resin, fluoropolymer, polyolefin (e.g., polyethylene, polypropylene, etc.), polyamide, acrylic resin, polyimide, polyvinyl chloride, etc., can be used to cover the electrode tabs. As for the covering method, a liquid resin can be coated on the electrode tabs and cured (furthermore, it can be dried as needed), or an insulating tape can be wrapped around the electrode tabs. From the viewpoint of improving voltage withstand capability, the thickness of the insulating material covering the electrode tabs is preferably 1.0 μm or more, more preferably 10 μm or more, further preferably 100 μm or more, even more preferably 300 μm or more, particularly preferably 500 μm or more, and most preferably 1000 μm or more.

[0065] As described above, regarding the unique problem of reduced voltage withstand when using spacers with conductive layers in batteries, the effect of improving voltage withstand can be achieved by covering the electrode tabs with insulating material. Therefore, in principle, this is not limited to a specific type of battery; the effect of this invention applies to any type of battery that uses spacers with conductive layers. Specifically, examples of batteries that can be implemented as another embodiment include lead-acid batteries, lithium-ion batteries, and redox flow batteries.

[0066] Furthermore, the battery of this embodiment can arbitrarily combine the features of the above-described battery design or (I) to (VI), and a battery that satisfies at least one of (I) to (VI) is also an embodiment of the present invention. The following describes a common or preferred structure for a battery that satisfies at least one of (I) to (VI) and its manufacturing method.

[0067] Substrate

[0068] In this embodiment, to allow ions to pass through and prevent short circuits, the substrate is preferably a microporous insulating film, more preferably an insulating film containing polyolefins and / or inorganic particles. The substrate of the insulating film can be a single layer or multiple layers, and examples include a substrate on which an inorganic layer composed of inorganic particles and a resin binder is applied to one or both sides of a microporous membrane containing polyolefins.

[0069] Furthermore, regarding the shape of the substrate, a rectangular sheet is described as the preferred shape in this embodiment, but within the scope of achieving the effects of the present invention, a circular sheet may also be used, for example. An application using a circular substrate is illustrated below. Figure 11 When using a circular substrate 6, such as Figure 11 As shown, the shortest distance in this invention always refers to the shortest distance d between the conductive layer 7 at the end of the substrate and the tab T, and does not represent the distance or path along the outer periphery of the circular substrate (not shown).

[0070] The average flow pore size of the microporous substrate is preferably 500 nm or less, more preferably 400 nm or less, even more preferably 300 nm or less, even more preferably 200 nm or less, even more preferably 175 nm or less, even more preferably 150 nm or less, significantly preferably 125 nm or less, particularly preferably 100 nm or less, and most preferably 80 nm or less. On the other hand, from the viewpoint of suppressing the microporous structure of the substrate from becoming closed due to byproducts of the charging and discharging reaction of the battery, the average flow pore size is preferably 1 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and even more preferably 20 nm or more.

[0071] Furthermore, from the viewpoint of suppressing electrical short circuits, the maximum pore size of the substrate is preferably 2000 nm or less, more preferably 1000 nm or less, even more preferably 800 nm or less, even more preferably 500 nm or less, even more preferably 400 nm or less, even more preferably 300 nm or less, even more preferably 200 nm or less, even more preferably 175 nm or less, even more preferably 150 nm or less, even more preferably 125 nm or less, or even more preferably 100 nm or less. Furthermore, from the viewpoint of suppressing the micropores of the substrate from becoming closed due to byproducts accompanying the charging and discharging reactions of the battery, the maximum pore size of the substrate is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, and particularly preferably 30 nm or more.

[0072] The maximum pore size and average flow pore size of the substrate can be determined in the following way.

[0073] Maximum aperture

[0074] The measuring apparatus used was a portable porosimeter (model: CFP-1500AL) from PMI (Porous Materials, Inc.). The substrate was used as the test sample. Compressed air was passed through the substrate while all its pores were filled with a test liquid of known surface tension, and the pore size was measured. For the test liquid, Galwick solution manufactured by PMI was used for test samples with a maximum pore size less than 100 μm, and pure water was used for test samples with a maximum pore size greater than 100 μm. First, substrate cut into 25 mm Φ pieces was immersed in the test liquid, and after removing excess liquid, the measurement was performed. The pore size could be calculated based on the pressure of air passing through the pores filled with the test liquid and the surface tension of the test liquid, using the following formula.

[0075] d pore =C·γ / P

[0076] {wherein, d} pore γ is the pore size of the substrate, γ is the surface tension of the test liquid, P is the minimum air pressure required for air to pass through the pore size, and C is a constant.

[0077] First, the airflow rate (wetting flow rate) is measured as the pressure P applied to the substrate immersed in the test solution is continuously increased. Initially, the sample, such as the nonwoven fabric, is in a state where all the pores are filled with the test solution, therefore the airflow rate is 0. However, as the pressure increases, air soon passes through the pores with the largest pore size, and a positive airflow rate is observed for the first time (this moment is called the bubble point). The maximum pore size d in this specification... max It refers to the fine pore size of the substrate at the bubble point.

[0078] <Average flow rate orifice size>

[0079] In the above-mentioned maximum pore size determination, after the bubble point, as the pressure is further increased, the air flow rate increases, approaching the air flow rate (drying flow rate) of the substrate in a dry state. The air flow rate after the moment when the smallest pore opens is exactly the same as the drying flow rate. In this determination method, the value obtained by dividing the wetting flow rate under a certain air pressure condition by the drying flow rate under the same pressure condition is defined as the cumulative filter flow rate (unit: %). In this specification, the pore size that opens at an air pressure where the cumulative filter flow rate is 50% is defined as the average flow pore size.

[0080] The substrate is not particularly limited as long as it has micropores that allow ions to permeate, but preferably includes thermoplastic polymers such as polyethylene compounds and polyolefins (polypropylene, polyethylene); thermosetting polymers such as phenolic resins; rubber materials such as natural or synthetic rubber and latex; fibrous materials such as synthetic wood pulp (SWP), glass fiber, synthetic fiber, and cellulose fiber; and porous membranes made of natural or synthetic materials such as combinations thereof. When the substrate is used in lead-acid batteries, it is preferable to include polyethylene. From the viewpoint of improving membrane strength or battery durability, polyethylene is preferably high molecular weight polyethylene with a weight-average molecular weight of 600,000 or more. Polyethylene is more preferably ultra-high molecular weight polyethylene (UHMWPE), i.e., polyethylene with a weight-average molecular weight of 1,000,000 or more, particularly preferably with a weight-average molecular weight of 4,000,000 or more, and most preferably with a weight-average molecular weight of 5,000,000 to 8,000,000. It should be noted that ultra-high molecular weight polyethylene in this specification refers to polyethylene with a weight-average molecular weight of 1,000,000 or more.

[0081] When the substrate of this embodiment is used in a lead-acid battery, it is preferable to contain 10 parts by mass and 40 parts by mass or less of polyethylene relative to 100 parts by mass of the substrate. From the viewpoint of improving the mechanical film strength and oxidation resistance of the substrate by means of polyethylene, the content of polyethylene relative to 100 parts by mass of the substrate is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, further preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more. Furthermore, from the viewpoint of reducing the proportion of hydrophobic polyethylene in the substrate and reducing the internal resistance of the lead-acid battery caused by the substrate, the substrate preferably contains hydrophilic inorganic particles. In this case, the content of polyethylene relative to 100 parts by mass of the substrate is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and further preferably 30 parts by mass or less. In addition, when the substrate is used in a battery other than a lead-acid battery, the lower limit of the polyethylene content relative to 100 parts by mass of the substrate is not particularly limited, but it may, for example, exceed 0 parts by mass or 1 part by mass or more.

[0082] When the substrate of this embodiment is used in a lead-acid battery, it is preferable to contain 40 parts by mass and 70 parts by mass of inorganic particles relative to 100 parts by mass of the substrate. From the viewpoint of improving the hydrophilicity of the substrate, it is preferable to contain 40 parts by mass and 45 parts by mass and 50 parts by mass of inorganic particles relative to 100 parts by mass of the substrate. Furthermore, if the mass ratio of inorganic particles in the substrate is large, the mass ratio of polyethylene becomes relatively low, and the adhesion between the inorganic particles and polyethylene becomes weak. Therefore, it is preferable to contain 70 parts by mass and 0.5% of inorganic particles relative to 100 parts by mass of the substrate, more preferably 69 parts by mass and 0.5%, further preferably 68 parts by mass and 0.5%, further preferably 67 parts by mass and 0.5%, further preferably 66 parts by mass and 0.5%, further preferably 65 parts by mass and 0.5%, further preferably 64 parts by mass and 0.5%, further preferably 63 parts by mass and 0.5%, further preferably 62 parts by mass and 0.5%, or further preferably 61 parts by mass and 0.5%.

[0083] Examples of inorganic particle materials included in the substrate include silica (amorphous silica, precipitated silica, gelled silica, fumed silica, etc.), alumina, sulfates (e.g., barium sulfate, calcium sulfate), titanium dioxide (rutile, anatase), gibbsite, bayerite, boehmite, zirconium oxide, magnesium oxide, cerium oxide, yttrium oxide, iron oxide and other oxide-based ceramics, silicon nitride, titanium nitride and boron nitride and other nitride-based ceramics, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, magnesium hydroxide, potassium titanate, talc, and synthetic kaolinite. Kaolinite, kaolin clay, kaolin (kaolinite, dickite, nacrite), calcined kaolin, frapontite, stevensite, dickite, nacrite, halloysite, pyrophyllite, odinite, montmorillonite, beidellite, nontronite, volkonskoite, saponite, hectorite, fluorine hectorite, sauconite, swinefordite, vermiculite, fluorine vermiculite Vermiculite, berthierine, sericite, amesite, kerolite, fraiponite, brindleyite, bentonite, zeolite, biotite, phlogopite, fluorophlogopite, firite, eastonite, taeniolite, siderophylite, tetraferroferromite, lepidolite, fluorotetrasilicic mica, polylithionite, muscovite, celadonite, ferroaluminite, aluminaluminite, tobelite, sodium mica, clintonite, kinoshitaite, brittle micaMica, anandite, pearl mica, clinochore, chamosite, pennantite, nimite, bailey chlorite, donbassite, cookite, sudoite, hydrotalcite, calcium silicate, magnesium silicate, aluminum silicate, diatomite, and silica sand, etc.

[0084] In the above examples, the inorganic particles used as the substrate are preferably silica, alumina, kaolin, titanium dioxide, aluminum silicate or barium sulfate particles with excellent acid and oxidation resistance and high hydrophilicity, more preferably silica particles, and even more preferably amorphous silica particles manufactured by sedimentation.

[0085] The inorganic particles in this embodiment can be used alone or in combination of two or more.

[0086] When the substrate of this embodiment is used in a lead-acid battery, from the viewpoint of improving the oxidation resistance of the substrate, it is preferable to include 0.1 to 35 parts by weight of plasticizer relative to 100 parts by weight of the substrate. The plasticizer is preferably an oil, but may be petroleum, paraffin-based mineral oil, mineral oil, or any combination thereof.

[0087] The substrate thickness in this embodiment is not particularly limited, but from the viewpoint of reducing the ion resistance within the battery, it is preferably 5.0 mm or less, more preferably 3.0 mm or less, even more preferably 2.0 mm or less, and even more preferably 1.5 mm or less. Furthermore, from the viewpoint of increasing the shortest distance between the conductive layer and the electrode tab to improve voltage withstand capability, the substrate thickness is preferably 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, even more preferably 15 μm or more, even more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 200 μm or more, even more preferably 300 μm or more, even more preferably 400 μm or more, even more preferably 500 μm or more, even more preferably 600 μm or more, even more preferably 670 μm or more, even more preferably 700 μm or more, even more preferably 800 μm or more, even more preferably 900 μm or more, even more preferably 950 μm or more, or even more preferably 1000 μm or more.

[0088] It should be noted that the substrate of this specification can be in the state of having multiple insulating layers stacked, for example, non-woven fabric (cellulose, polyethylene terephthalate, etc.) can be stacked on the surface of a microporous polyethylene membrane, and the above thickness refers to the total thickness in the state of having insulating layers stacked.

[0089] It should be noted that, for example, when the lead-acid battery spacer substrate of this embodiment is manufactured by extrusion molding, ribs (convex shapes) can be imparted to the surface of the spacer in any shape using a mechanical press, calender stack, calender roll, or pattern roll after the spacer is extruded. In some embodiments, the spacer may have ribs on at least its surface. For example, when a conductive layer is provided on the surface of a substrate with a smooth surface and ribs on the back side, the presence of the ribs on the back side increases the distance between the conductive layer at the end of the spacer and the negative electrode tab when the conductive layer is in electrical contact with the positive electrode. Increasing the overall thickness of the substrate can also increase the distance between the conductive layer at the end of the spacer and the negative electrode tab. On the other hand, since the ionic conductivity decreases as the overall thickness of the spacer increases, it is preferable to have ribs on the substrate surface opposite to the surface with the conductive layer.

[0090] Conductive layer of spacer

[0091] Examples of conductive materials used to form the conductive layer in this embodiment include conductors such as carbon materials, metals, and metal oxides; conductive polymers; semiconductors; and inorganic or organic compounds that have acquired conductivity through doping. The method for forming this conductive layer is not particularly limited, but one example is a method of applying a liquid containing the conductive material to a substrate and then drying it. Examples of coating methods include die coating, gravure coating, spraying, roller coating, screen printing, and inkjet printing. Other methods for forming the conductive layer include vapor deposition (sputtering, vacuum deposition, etc.) of the conductive material (e.g., metal or metal oxide) onto a substrate.

[0092] Examples of carbon materials include graphite, soft carbon, hard carbon, activated carbon, carbon black, graphene, carbon nanotubes, and fullerenes, as well as carbon clusters, bulk carbon materials, and mixtures thereof. Among these carbon materials, from the viewpoint of reducing surface resistivity, one or more materials selected from the group consisting of furnace black, acetylene black, Ketjen black, graphite, and carbon nanotubes are preferred. From the viewpoint of uniform dispersion, when using carbon nanotubes, monolayer carbon nanotubes are more preferred.

[0093] Regarding metals, there are no particular limitations, but examples include iron, aluminum, copper, zinc, nickel, chromium, titanium, silver, gold, platinum, palladium, tungsten, lithium, cobalt, manganese, sodium, or alloys containing them. As metal oxides, examples include conductive materials of indium tin oxide (ITO) or fluorine-doped tin oxide (FTO).

[0094] The conductive layer can be disposed on one or both sides of the substrate. Examples of single-sided coating of the conductive layer relative to the substrate are not limited, but are shown in... Figures 2-8On the other hand, Figure 12 This is a schematic perspective view illustrating an application example of a conductive layer being coated on both sides of a substrate according to an embodiment of the present invention.

[0095] like Figure 12 As shown in (a), with the substrate 6 of the spacer 5 as a reference, the conductive layer 7 on one side and the substrate end and electrode active material layer E attached to the substrate 5 are... A When the electrode tabs T are connected, the shortest distance of the present invention refers to the shortest distance d between the conductive layer 7 on one side and the electrode tab T, which is also considered as part of the electrode tab T.

[0096] like Figure 12 As shown in (b), with the substrate 6 of the spacer 5 as a reference, the conductive layer 7 on one side and the electrode active material layer E attached thereto... A When the electrode tab T is connected, but not connected to the substrate end of the substrate 5, the shortest distance of the present invention refers to the shortest distance d between the conductive layer 7 on one side and the electrode tab T, which is also considered as part of the electrode tab T.

[0097] When the conductive layer is formed relative to a portion of the substrate surface, the conductive layer can be applied to a desired location on the substrate using the following methods: pre-covering a portion of the substrate with a mask material, applying (e.g., vapor deposition or coating) a conductive material to the exposed surface of the substrate, and then removing the mask material; screen printing a desired pattern using a screen mask; pattern printing via die coating or gravure coating; pattern coating via inkjet printing, etc. For example, an example of forming a striped pattern on at least a portion of the substrate surface of the spacer is shown below. Figure 8 .exist Figure 8 In (a), there is a substrate 6 that is a non-conductive layer portion, and a spacer 5 that has a conductive layer 7 but does not have a conductive layer 7 in a striped pattern on a part of the substrate is disposed between the positive and negative electrodes in such a way that the conductive layer 7 is opposite to the negative electrode 3 to form a laminate. Figure 8 (b) is a schematic diagram (b) viewed from the negative pole side of the laminate, and Figure 8 (c) is a cross-sectional view (c) between the dashed lines ab of the stacked body.

[0098] By electrically connecting a conductive layer with low surface resistance to the positive or negative electrode of the battery, the conductive layer acts as a grid or current collector of the electrode, promoting the acceptance and transfer of electrons to the active material. Therefore, the surface resistance of the conductive layer is preferably 10000Ω or less, more preferably 5000Ω or less, even more preferably 800Ω or less, and even more preferably 600Ω or less.

[0099] The thickness of the conductive layer in this embodiment is not particularly limited, but from the viewpoint of reducing surface resistivity by increasing the thickness of the conductive layer, the thickness of the conductive layer is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, even more preferably 30 nm or more, even more preferably 40 nm or more, even more preferably 50 nm or more, even more preferably 60 nm or more, even more preferably 100 nm or more, even more preferably 200 nm or more, even more preferably 400 nm or more, even more preferably 600 nm or more, even more preferably 800 nm or more, or even more preferably 1000 nm or more. Furthermore, as the conductive layer becomes thicker, the ion resistance within the battery increases; therefore, the thickness of the conductive layer is preferably 5 mm or less, more preferably 0.1 mm or less, even more preferably 0.01 mm or less, even more preferably 0.005 mm or less, or even more preferably 0.003 mm or less.

[0100] From the viewpoint of reducing the ion resistance within the battery, the thickness of the conductive layer is preferably 5.0 mm or less, more preferably 3.0 mm or less, even more preferably 2.0 mm or less, and even more preferably 1.5 mm or less. The thickness of the conductive layer is determined by observing the thickness in a cross-sectional SEM (scanning electron microscope) and calculating the arithmetic mean of the thicknesses of the five regions when the thicknesses are measured in five different regions within the observed section.

[0101] Positive electrode, positive electrode tab, negative electrode, negative electrode tab, electrolyte or electrolyte solution

[0102] In the case where the battery in this invention is a lead-acid battery, one method of using a lead-acid battery can utilize a battery case, a grid made of lead or a lead alloy, a positive electrode made of lead dioxide positive electrode active material, a positive electrode tab made of lead or a lead alloy, a grid made of lead or a lead alloy, a negative electrode made of lead or a lead alloy active material, a negative electrode tab made of lead or a lead alloy, and dilute sulfuric acid as an electrolyte.

[0103] Furthermore, when the battery in this invention is a lithium-ion battery, as one type of lithium-ion battery, examples include a positive electrode on an aluminum foil of a positive current collector with a positive active material, an aluminum positive electrode tab electrically connected to the positive current collector, a negative electrode on a copper foil of a negative current collector with a negative active material, a nickel negative electrode tab electrically connected to the negative current collector, and a carbonate-based organic solvent containing lithium salts such as lithium hexafluorophosphate (LiPF6) or lithium borofluoride (LiBF4).

[0104] Examples of positive electrode active materials include lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate oxide (LiFePO4), nickel cobalt aluminum oxide (NCA), nickel manganese cobalt oxide (NMC), and lithium nickel oxide (LiNiO2). Furthermore, examples of negative electrode active materials include graphite, silicon, and lithium titanium oxide (Li4Ti5O2). 12 Lithium iron phosphate (LiFePO4), lithium metal or lithium alloy, etc.

[0105] <Method for manufacturing substrate>

[0106] The following describes a method for manufacturing a substrate for a spacer in a lead-acid battery, using a substrate made of polyolefin, such as ultra-high molecular weight polyethylene, as an example. However, the substrate is not limited to the substrate obtained by the following manufacturing method, as long as the layer disclosed herein can be formed thereon.

[0107] The method for manufacturing the substrate includes the following steps: The process of preparing thermoplastic polymers, such as ultra-high molecular weight polyethylene (hereinafter referred to as "UHMWPE"); The process of preparing particulate fillers such as particles; The process of preparing a plasticizer for processing as a liquid at room temperature (25°C); The process of mixing UHMWPE, particulate fillers and processing plasticizers to form a mixture; The process of extruding the mixture through a die, such as a slit die or an inflation die, to form a sheet; and The extraction process involves partially or completely removing the plasticizer from the film, thereby forming a microporous membrane.

[0108] After the process of forming the above-mentioned sheet and before the extraction process, the sheet can be further processed by casting, calendering, or blow molding on cooling rollers. Then, the sheet processed by the casting or calendering process is provided to the extraction process to partially or completely remove the plasticizer, thereby forming micropores in the substrate.

[0109] The substrate obtained by the above method comprises UHMWPE, a plasticizer (in the case of partial extraction), and a particulate filler. From the viewpoint of acid resistance and heat resistance, the particulate filler is preferably inorganic particles. These micropores preferably occupy 25% to 90% of the total volume of the substrate, more preferably 30% to 80%, and even more preferably 40% to 70%.

[0110] The substrate manufacturing method can also perform stretching processes before and after the extraction process and / or use embossing rollers or calendering rollers to impart any structure to the substrate surface.

[0111] Example

[0112] The embodiments of this disclosure are described in detail below, but these are for illustrative purposes only, and the scope of this disclosure is not limited to the following embodiments. Table 1 shows various evaluation results of the spacers and batteries obtained in the embodiments and comparative examples. The evaluation methods for various layer properties are described below.

[0113] The production of substrates

[0114] The substrates used in Examples 1, 2, 7, 14, and Comparative Example 4 were prepared as follows. Ultra-high molecular weight polyethylene resin powder, surfactant, mineral oil, and sedimentation-processed amorphous silica with a median particle size of 31 μm and a DOA oil absorption (dioctyl adipate oil absorption) of 283 ml / 100 g were heated and melt-mixed in a mixer to obtain a raw material composition. This raw material composition was extruded using an extruder with a T-die at the tip at a temperature above the melting point of the polyethylene, and then passed through calendering rolls to obtain a film. Next, the film was immersed in a solvent to remove a portion of the mineral oil, and then dried and cooled to obtain an elongated spacer (substrate) for evaluation, having a composition of 22 parts by mass of polyethylene resin, 56 parts by mass of silica, 2 parts by mass of surfactant, and 20 parts by mass of mineral oil. The substrate had flat surfaces on both sides, a substrate thickness of 500 μm, an average flow pore size of 30 nm, and a maximum pore size of 83 nm.

[0115] The substrates used in Examples 9, 10, 11, 15, and Comparative Example 1 were prepared as follows. Ultra-high molecular weight polyethylene resin powder, surfactant, mineral oil, and sedimentation-processed amorphous silica with a median particle size of 31 μm and a DOA oil absorption of 283 ml / 100 g were heated and melt-mixed in a mixer to obtain a raw material composition. This raw material composition was extruded using an extruder with a T-die at the tip at a temperature above the melting point of the polyethylene, and then passed between calendering rolls to obtain a film. Next, the film was impregnated in a solvent to remove a portion of the mineral oil, and then dried and cooled to obtain an elongated spacer (substrate) for evaluation, having a composition of 22 parts by mass of polyethylene resin, 56 parts by mass of silica, 2 parts by mass of surfactant, and 20 parts by mass of mineral oil. The substrate had flat surfaces on both sides, a substrate thickness of 250 μm, an average flow pore size of 40 nm, and a maximum pore size of 82 nm.

[0116] The substrates used in Examples 12, 13, and 16 were prepared as follows. Ultra-high molecular weight polyethylene resin powder, surfactant, mineral oil, and sedimentation-processed amorphous silica with a median particle size of 31 μm and a DOA oil absorption of 283 ml / 100 g were heated and melt-mixed in a mixer to obtain a raw material composition. This raw material composition was extruded using an extruder with a T-die at the tip at a temperature above the melting point of the polyethylene, and then passed between calendering rolls to obtain a film. Next, the film was impregnated in a solvent to remove a portion of the mineral oil, and then dried and cooled to obtain an elongated spacer (substrate) for evaluation, comprising 22 parts by mass of polyethylene resin, 56 parts by mass of silica, 2 parts by mass of surfactant, and 20 parts by mass of mineral oil. The substrate was flat on both sides, with a thickness of 160 μm, an average flow pore size of 32 nm, and a maximum pore size of 88 nm.

[0117] The substrate used in Comparative Example 2 was prepared as follows. Ultra-high molecular weight polyethylene resin powder, surfactant, mineral oil, and sedimentation-processed amorphous silica with a median particle size of 31 μm and a DOA oil absorption of 283 ml / 100 g were heated and melt-mixed in a mixer to obtain a raw material composition. This raw material composition was extruded using an extruder with a T-die at the tip at a temperature above the melting point of the polyethylene, and then passed between calendering rolls to obtain a film. Next, the film was impregnated in a solvent to remove a portion of the mineral oil, and then dried and cooled to obtain an elongated spacer (substrate) for evaluation, having a composition of 22 parts by mass of polyethylene resin, 56 parts by mass of silica, 2 parts by mass of surfactant, and 20 parts by mass of mineral oil. The substrate had flat surfaces on both sides, a thickness of 400 μm, an average flow pore size of 42 nm, and a maximum pore size of 78 nm.

[0118] The substrates used in Examples 3, 8, and Comparative Example 3 were prepared as follows. Ultra-high molecular weight polyethylene resin powder, surfactant, mineral oil, and sedimentation-processed amorphous silica with a median particle size of 31 μm and a DOA oil absorption of 283 ml / 100 g were heated and melt-mixed in a mixer to obtain a raw material composition. This raw material composition was extruded using an extruder with a T-die at the tip at a temperature above the melting point of the polyethylene, and then passed through calendering rolls to obtain a film. Next, the film was immersed in a solvent to remove a portion of the mineral oil, and then dried and cooled to obtain an elongated spacer (substrate) for evaluation, comprising 22 parts by mass of polyethylene resin, 56 parts by mass of silica, 2 parts by mass of surfactant, and 20 parts by mass of mineral oil. One side of this substrate was flat, while the opposite side was formed with a dotted convex shape. The thickness of the flat portion was 250 μm, the thickness of the substrate including the convex portion was 655 μm, the average flow pore size was 40 nm, and the maximum pore size was 80 nm. In Examples 4, 5, and 6, nonwoven fabrics made of cellulose fibers with different thicknesses were laminated on the surface of the protruding side of the substrate used in Example 3. The substrate thickness in Example 4 was 754 μm, the substrate thickness in Example 5 was 893 μm, and the thickness in Example 6 was 950 μm.

[0119] Fabrication of spacers for withstand voltage testing

[0120] To form the conductive layers of Examples 1, 2, and 14, a slurry was first prepared. Carbon black, acrylic resin, ionic surfactant, tackifier, and carbon nanotubes, as solid components, were dispersed and mixed in water to prepare a slurry with a solid component concentration of 1% by mass. The total mass of the solid components in the slurry (corresponding to the total mass of the resulting layers) was set at 100 parts by mass. The slurry was prepared with 65.5 parts by mass of carbon black (furnace black) with a center particle size (d50) of 0.8 μm, 19.7 parts by mass of ionic surfactant, 13.0 parts by mass of acrylic resin (water-based latex) (converted to solid components), 1.3 parts by mass of tackifier, and 0.5 parts by mass of monolayer carbon nanotubes. Using a coating applicator, the slurry was manually applied to the entire surface of a single (flat) side of a substrate prepared as a 20 cm × 20 cm substrate for Examples 1, 2, and 14, and dried in an oven at 80°C for 5 minutes. At this point, the slit of the dressing (the gap formed between the spacer and the dressing) is 45 μm, and the layer obtained after drying is 5 μm. A 7 cm × 7 cm section is cut from the central part of the obtained sample to obtain a spacer with a conductive layer on the entire surface of one side of the substrate.

[0121] To form the conductive layers of Examples 3, 4, 5, 6, 12, 13, 16, and Comparative Examples 1-2, a slurry was first prepared. Carbon black, acrylic resin, ionic surfactant, tackifier, and carbon nanotubes, which are solid components, were dispersed and mixed in water to prepare a slurry with a solid component concentration of 1% by mass. At this time, the total mass of the solid components in the slurry (corresponding to the total mass of the resulting layers) was set as 100 parts by mass. The slurry was prepared with 65.6 parts by mass of carbon black (furnace black) with a central particle size (d50) of 0.8 μm, 19.7 parts by mass of ionic surfactant, 13.1 parts by mass of acrylic resin (water-based latex) (converted to solid component), 1.3 parts by mass of tackifier, and 0.3 parts by mass of monolayer carbon nanotubes. Using a dressing applicator, the paste was manually applied to the entire flat surface of one side of the substrates used in Examples 3, 4, 5, 6, 12, 13, 16, and Comparative Examples 1-2, which were prepared in 20cm × 20cm sizes. The substrates were then dried in an oven at 80°C for 5 minutes. At this point, the slit of the dressing applicator (the gap formed between the spacer and the dressing applicator) was 45μm, and the resulting layer after drying was 5μm thick. A 7cm × 7cm section was cut from the center of the obtained sample to obtain a spacer with a conductive layer on the entire flat surface of one side of the substrate.

[0122] To form the conductive layer of Example 7, a slurry was first prepared. Carbon black, acrylic resin, ionic surfactant, and tackifier, as solid components, were dispersed and mixed in water to prepare a slurry with a solid component concentration of 1% by mass. The total mass of the solid components in the slurry (corresponding to the total mass of the resulting layer) was set at 100 parts by mass. The slurry was prepared with 65.8 parts by mass of carbon black (furnace black) with a center particle size (d50) of 1.0 μm, 19.7 parts by mass of ionic surfactant, 13.2 parts by mass of acrylic resin (water-based latex) (converted from solid component concentration), and 1.3 parts by mass of tackifier. Using a coating applicator, the slurry was manually applied to the entire surface of one side (flat surface) of the substrate used in Example 7, which was prepared to a size of 20 cm × 20 cm, and dried in an oven at 80°C for 5 minutes. At this point, the slit of the dressing (the gap formed between the spacer and the dressing) is 45 μm, and the layer obtained after drying is 5 μm. A 7 cm × 7 cm section is cut from the central part of the obtained sample to obtain a spacer with a conductive layer on one side of the substrate.

[0123] To form the conductive layers of Examples 8 and 9, a slurry was first prepared. Carbon black, acrylic resin, ionic surfactant, tackifier, and carbon nanotubes, as solid components, were dispersed and mixed in water to prepare a slurry with a solid component concentration of 1% by mass. At this time, the total mass of the solid components in the slurry (corresponding to the total mass of the resulting layers) was set as 100 parts by mass. The slurry was prepared with 65.6 parts by mass of carbon black (furnace black) with a central particle size (d50) of 0.8 μm, 19.7 parts by mass of ionic surfactant, 13.1 parts by mass of acrylic resin (water-based latex) (converted from solid component concentration), 1.3 parts by mass of tackifier, and 0.3 parts by mass of monolayer carbon nanotubes. A portion of one side (flat surface) of the substrate used in Examples 8 and 9, measuring 20cm × 20cm, was adhered to a 20μm thick resin tape. For this substrate, the slurry was manually applied to the entire surface using a dressing applicator and dried in an oven at 80°C for 5 minutes. At this point, the slit of the dressing applicator (the gap formed between the spacer and the dressing applicator) was 45μm, and the resulting layer after drying was 5μm. The resin tape was then peeled off, and the resulting sample was cut into 7cm × 7cm pieces, as shown. Figure 8 As shown, a sample is shown where a portion of the surface of the substrate 6, which is used to fabricate the spacer 5 for voltage withstand testing, is striped and does not have a conductive layer 7.

[0124] To form the conductive layers of Examples 10, 11, and 15, a slurry was first prepared. Carbon black, acrylic resin, ionic surfactant, tackifier, and carbon nanotubes, as solid components, were dispersed and mixed in water to prepare a slurry with a solid component concentration of 1% by mass. At this time, the total mass of the solid components in the slurry (corresponding to the total mass of the resulting layers) was set as 100 parts by mass. The slurry was prepared with 65.6 parts by mass of carbon black (furnace black) with a central particle size (d50) of 0.8 μm, 19.7 parts by mass of ionic surfactant, 13.1 parts by mass of acrylic resin (water-based latex) (converted from solid component concentration), 1.3 parts by mass of tackifier, and 0.3 parts by mass of monolayer carbon nanotubes. A 20 μm thick resin tape was adhered to a portion of one side (flat surface) of the substrates used in Examples 10, 11, and 15, which were fabricated to a size of 20 cm × 20 cm. Using this tape as a mask, the slurry was manually applied to the entire surface of the substrate using a dressing applicator and dried in an oven at 80°C for 5 minutes. At this point, the slit of the dressing applicator (the gap formed between the spacer and the dressing applicator) was 45 μm, and the resulting layer after drying was 5 μm. The resin tape was then peeled off, yielding a 7 cm × 7 cm spacer with a 1 mm wide outer circumference and no conductive layer (no conductive layer at the ends of the substrate).

[0125] It should be noted that the spacers used for the withstand voltage test in Comparative Examples 3 and 4 did not have a conductive layer on the substrate surface, and were cut to a size of 7cm × 7cm for the withstand voltage test. Regarding the sample of Comparative Example 3, the withstand voltage test was conducted in the direction where the protrusion on the substrate surface was connected to the positive electrode.

[0126] Surface resistance of conductive layers

[0127] In the surface resistivity measurement, a refractometer (RM3545 RESISTANCE METER) manufactured by HIOKI Electric Co., Ltd. was used as the probe, employing a 4-probe probe (5.0 mm pitch). For the conductive layer of the spacer, the resistance of the conductive layer was measured at 6 points under the following measurement conditions by pressing the 4-probe probe. The average value of these measurements was calculated and recorded as the surface resistivity in Table 1. The unit is Ω. The software used for this measurement was the 4-probe method resistivity meter-PC application. The measurement mode was selected as "Normal Measurement," and the measurement unit was selected as "Resistance [Ω]." The measurement conditions are as follows. The surface resistivity values ​​of the evaluated spacers are recorded in Table 1.

[0128] [Measurement Conditions]

[0129] The long side of the sample is 100 mm.

[0130] The short side of the sample is 100 mm.

[0131] The thickness of the sample is 10 μm.

[0132] x-coordinate: 50mm.

[0133] Y-coordinate: 50mm.

[0134] Probe used: 5.0mm.

[0135] Substrate Thickness

[0136] The sample for voltage withstand testing was then prepared, embedded in epoxy resin, and subjected to cross-sectional SEM (scanning electron microscopy) observation. The substrate thickness was calculated by taking the arithmetic mean of the thicknesses of five different regions measured in the observed area. In cases where the substrate surface has protrusions, the substrate thickness was calculated by taking the arithmetic mean of the thicknesses including the protrusions through cross-sectional SEM observation. Furthermore, the substrate can be in a state where multiple insulating layers are stacked. In the case where a nonwoven fabric is stacked on the surface of a polyethylene microporous membrane, the aforementioned thickness refers to the total thickness calculated when insulating layers are stacked. The measured thicknesses are recorded in Table 1.

[0137] Voltage withstand test

[0138] The withstand voltage of the examples and comparative examples was determined in the following order. A TOS5200 apparatus manufactured by Kikusui Co., Ltd. of Japan was used in the evaluation. Various spacers were cut into 7cm square pieces, according to... Figure 9 In the sequence shown, a spacer 5 is clamped between two electrodes with electrode tabs, each 5 cm square in size (at this time, the spacer 5, cut to 7 cm square in size, has a 5 cm square electrode placed in the center). This laminate is then clamped with an 11 cm × 11 cm polycarbonate plate (9, 9), and the four corners of the polycarbonate plate (9, 9) are fixed with screws. This creates a sample for withstand voltage testing. The electrode tabs are clamped with a fixture, and a withstand voltage test is performed. The electrode surfaces with the conductive layers connected to the spacers are listed in Table 1. Furthermore, the presence or absence of a conductive layer at the substrate end and the shortest distance between the conductive layer at the substrate end and the electrode tabs are also listed in Table 1. Regarding the shortest distance between the conductive layer at the substrate end and the negative or positive electrode tab, the same withstand voltage test sample is made again using a spacer with a conductive layer. After embedding in epoxy resin, it is then... Figure 9 The electrode tabs at the substrate end corresponding to the dashed line ab were exposed using a cross-sectional grinding machine. The shortest distance between the conductive layer at the substrate end and the electrode tab was determined using cross-sectional SEM, and the values ​​are recorded in Table 1. The unit is μm. The shortest distance between the conductive layer at the substrate end and the positive electrode tab is recorded when the conductive layer is connected to the negative electrode, and the shortest distance between the conductive layer at the substrate end and the negative electrode tab is recorded when the conductive layer is connected to the positive electrode. Figure 10 This illustrates the contrast between the embodiments and comparative examples. Figure 9 A schematic cross-sectional view of part ab.

[0139] Furthermore, in Examples 12 and 16, the entire surface of the positive electrode tab was covered with an insulating tape made of resin with a thickness of 100 μm (excluding the tip of the tab, which is 2 cm wide and 1 cm high, to ensure conductivity). In Example 13, the entire surface of the negative electrode tab was covered with an insulating tape (excluding the tip of the tab, which is 2 cm wide and 1 cm high, to ensure conductivity). In other examples and comparative examples, no insulation treatment was performed on the electrode tabs. In Examples 12, 13, and 16, although the shortest distance between the conductive layer at the end of the substrate and the substrate tab was 260 μm, the electrode tab was covered with an insulating tape with a thickness of 100 μm. Therefore, the shortest distance between the conductive layer at the end of the substrate and the electrode tab is indicated by parentheses as a reference value. In Examples 14 to 16, the positive electrode and the positive electrode tab were made of aluminum, and the negative electrode and the negative electrode tab were made of nickel. These positive and negative electrode tabs are materials commonly used in lithium-ion batteries. In the examples and comparative examples other than Examples 14-16, the positive electrode and positive electrode tab are made of pure lead, and the negative electrode and negative electrode tab are also made of pure lead. The lead in these positive and negative electrode tabs is the material used in lead-acid batteries.

[0140] The withstand voltage was measured under the following conditions: During the process of increasing the voltage between the electrodes from 0.0 kV to 1.5 kV over 2 seconds, the voltage at the moment when a current of 0.3 mA or more was detected was taken as the withstand voltage. If no current of 0.3 mA or more was detected even when the voltage increased to 1.5 kV, the withstand voltage was set to 1.50 kV. Furthermore, the withstand voltage was measured at 25°C. The evaluation sample was placed under a relative humidity (RH) of 50% for 30 minutes before the withstand voltage was measured. The results of the above withstand voltage measurements are recorded in Table 1.

[0141] [Table 1-1]

[0142] [Table 1-2]

[0143] Results regarding the embodiments and comparative examples

[0144] In Comparative Examples 3 and 4, where no conductive layer is present on the surface of the spacer, a high withstand voltage of 1.5 kV or more was obtained. On the other hand, in Examples 1-9 and 14, and Comparative Examples 1 and 2, which used spacers with conductive layers at the ends of the substrate, an improved withstand voltage was achieved by extending the shortest distance between the conductive layer at the ends of the substrate and the electrode tabs. From the viewpoint of setting the withstand voltage to 0.50 kV or more, the shortest distance is preferably 500 μm or more; from the viewpoint of setting the withstand voltage to 1.00 kV or more, the shortest distance is preferably 655 μm or more; and from the viewpoint of setting the withstand voltage to 1.50 kV or more, the shortest distance is preferably 950 μm or more.

[0145] According to Examples 10, 11, and 15, high voltage withstand is also observed when the conductive layer is electrically connected to the positive electrode and the spacer end opposite to the negative electrode tab does not have the conductive layer, or when the conductive layer is electrically connected to the negative electrode and the spacer end opposite to the positive electrode tab does not have the conductive layer. From the viewpoint of improving voltage withstand, it is preferable to have a portion without a conductive layer of 1 mm or more extending inward from the end of the substrate.

[0146] As can be seen from Examples 12, 13, and 16, even when the shortest distance between the conductive layer at the end of the substrate and the electrode tab is close, the withstand voltage is improved by insulating the electrode tab.

[0147] Industrial applicability

[0148] This invention can be applied to storage batteries, especially liquid secondary batteries or solid secondary batteries, and more specifically, to lead-acid batteries, lithium-ion batteries, redox flow batteries, etc.

[0149] Explanation of symbols

[0150] 1: Positive electrode.

[0151] 2: Positive electrode.

[0152] 3: Negative electrode.

[0153] 4: Negative electrode.

[0154] 5: Spacer.

[0155] 6: Substrate.

[0156] 6 E : End of substrate.

[0157] 7: Conductive layer.

[0158] 8: Insulation materials.

[0159] 9: Polycarbonate sheet.

[0160] 10: Positive electrode clamp.

[0161] 11: Negative electrode clamp.

[0162] T: Electrode tab.

[0163] E A Electrode active material layer.

[0164] d: The shortest distance between the conductive layer and the electrode tab.

[0165] d1: The shortest distance between the conductive layer and the negative electrode tab.

[0166] d2: The shortest distance between the conductive layer and the positive electrode tab.

Claims

1. A storage battery comprising a positive electrode with a positive tab, a negative electrode with a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, The conductive layer covers at least to the substrate end of the substrate adjacent to the positive or negative electrode tab, and... (I) The conductive layer is electrically connected to the positive electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the negative electrode tab and the negative electrode tab is 500 μm or more; and / or, (II) The conductive layer is electrically connected to the negative electrode, and the shortest distance between the conductive layer at the end of the substrate adjacent to the positive electrode tab and the positive electrode tab is more than 500 μm.

2. A storage battery comprising a positive electrode with a positive tab, a negative electrode with a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, (III) The conductive layer is electrically connected to the positive electrode, and the substrate end of the substrate adjacent to the negative electrode tab does not have the conductive layer; and / or, (IV) The conductive layer is electrically connected to the negative electrode, and the substrate end of the substrate adjacent to the positive electrode tab does not have the conductive layer.

3. A storage battery comprising a positive electrode with a positive tab, a negative electrode with a negative tab, and a spacer, characterized in that, The spacer is disposed between the positive electrode and the negative electrode, and the spacer has an exposed portion that protrudes from both electrodes. The spacer is composed of at least a substrate and a conductive layer covering a portion of the substrate, and, The conductive layer covers at least to the substrate end of the substrate adjacent to the positive or negative electrode tab, and... (V) The conductive layer is electrically connected to the positive electrode, and the surface of the negative electrode tab is covered with an insulating material; and / or, (VI) The conductive layer is electrically connected to the negative electrode, and the surface of the positive electrode tab is covered with an insulating material.

4. The storage battery according to claim 1, wherein, The shortest distance is less than 1500 μm.

5. The storage battery according to claim 1, wherein, The shortest distance is 655 μm or more.

6. The storage battery according to claim 1, wherein, The shortest distance is 950 μm or more.

7. The storage battery according to any one of claims 1 to 6, wherein, The substrate is a rectangular sheet.

8. The storage battery according to any one of claims 1 to 6, wherein, The surface resistance of the conductive layer is below 5000Ω.

9. The storage battery according to any one of claims 1 to 6, wherein, The conductive layer contains carbon material.

10. The storage battery according to any one of claims 1 to 6, wherein, The substrate comprises polyolefin.

11. The storage battery according to any one of claims 1 to 6, wherein, The positive electrode tab and the negative electrode tab contain lead.

12. The storage battery according to any one of claims 1 to 6, wherein, The positive electrode tab contains aluminum, and the negative electrode tab contains nickel.

13. The storage battery according to any one of claims 1 to 6, wherein, The battery in question is a lead-acid battery.

14. The storage battery according to any one of claims 1 to 6, wherein, The battery is a lithium-ion battery.

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