primary battery
By installing an electrolyte shielding section in the primary battery to cover the negative electrode lead, the heat generation problem during over-discharge is solved, improving the battery's safety and stability.
Patent Information
- Application Number
- CN202480084488.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-12
- Filing Date
- 2024-12-19
- Publication Date
- 2026-08-04
AI Technical Summary
When multiple primary batteries are connected and used, some of the batteries may become over-discharged, causing heat generation. This is especially true in lithium primary batteries, where the negative electrode leads and casing may dissolve, potentially causing internal short circuits and current concentration, leading to battery overheating.
A primary battery structure is designed, comprising a wound electrode assembly, an electrolyte, a casing, a sealing body, and a negative electrode lead. By providing a first electrolyte shielding portion between the negative electrode lead and the negative electrode, a portion of the negative electrode lead is covered, and the shielding portion extends across the end of the positive electrode in the winding axis direction of the electrode assembly, preventing electrolyte infiltration and suppressing heat generation during over-discharge.
It effectively suppresses heat generation during over-discharge, reduces the dissolution of the negative electrode leads, and improves the safety and stability of the battery.
Smart Images
Figure CN122514870A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to primary batteries. Background Technology
[0002] Previously, it was known that a primary battery had a negative electrode made of a consumable metal (for example, Patent Document 1). Patent Document 1 disclosed: "A non-aqueous electrolyte battery having an electrode body in which a positive electrode plate and a negative electrode plate made of a consumable metal plate such as a lithium plate or a sodium plate are closely disposed with a spacer between them. In the positive electrode plate, a region in the width direction opposite to the negative electrode plate has a positive electrode current collector tab and an insulating member protecting the tab, which is disposed thereon, and has an exposed portion that is not covered by the positive electrode current collector tab and the insulating member."
[0003] Prior art literature
[0004] Patent documents
[0005] Patent Document 1: Japanese Utility Model Publication No. 5-31810 Summary of the Invention
[0006] The technical problem that the invention aims to solve
[0007] When multiple primary batteries are connected together, some of them may become over-discharged, potentially generating heat. For example, when a lithium primary battery becomes over-discharged, the negative electrode leads and casing dissolve, and dendritic deposits form as metal on the positive electrode surface, which can penetrate the spacers and create an internal short circuit. This short circuit causes current concentration, resulting in battery heat generation. This type of over-discharge heat generation can also occur in the non-aqueous electrolyte battery of Patent Document 1. In such cases, one of the objectives of this disclosure is to suppress over-discharge heat generation.
[0008] Methods for solving problems
[0009] One aspect of this disclosure relates to a primary battery. The primary battery comprises: a wound electrode assembly having a positive electrode, a negative electrode made of a consumable metal, and a spacer between the positive and negative electrodes, having a first end face and a second end face opposite to it; an electrolyte; a bottomed cylindrical housing housing the electrode assembly and the electrolyte, and electrically connected to the positive electrode; a sealing body sealing the opening of the housing; a negative electrode lead having a first main face connected to the negative electrode and a second main face opposite to it, and protruding from the first end face to electrically connect the negative electrode to the sealing body; and a first electrolyte shielding portion having an intervening portion between the first main face of the negative electrode lead and the end of the negative electrode on the first end face side, covering a portion of the first main face and a portion of the second main face, the first electrolyte shielding portion extending across the end of the positive electrode on the first end face side in the winding axis direction of the electrode assembly.
[0010] Invention Effects
[0011] According to this disclosure, it is possible to suppress heat generation during over-discharge. Attached Figure Description
[0012] Figure 1 This is a front view of a portion of the primary battery of Embodiment 1, shown in a schematic longitudinal cross-section.
[0013] Figure 2 The diagram shows the main parts of the primary battery of Embodiment 1 in an enlarged view. (a) is the front view and (b) is the side view showing only the negative electrode lead and each electrolyte shielding part.
[0014] Figure 3 The diagram shows the main parts of the primary battery of Embodiment 2 in an enlarged view. (a) is the front view and (b) is the side view showing only the negative electrode lead and each electrolyte shielding part.
[0015] Figure 4 This is a front view showing the main parts of the primary battery in Embodiment 3 in an enlarged manner. Detailed Implementation
[0016] The following examples illustrate implementations of the primary battery involved in this disclosure. However, this disclosure is not limited to the examples described below. Specific values and materials are sometimes illustrated in the following description, but other values and materials can be applied as long as the effects of this disclosure are achieved.
[0017] The primary battery disclosed herein includes an electrode assembly, an electrolyte, a casing, a sealing body, a negative electrode lead, and a first electrolyte shielding portion. It should be noted that the following description uses a lithium primary battery as an example, but the primary battery disclosed herein may also be of other types.
[0018] The electrode assembly is a wound type electrode assembly having a positive electrode, a negative electrode, and a spacer, and having a first end face and a second end face opposite to it. The negative electrode is made of a consumable metal (in this example, lithium metal or a lithium alloy). The spacer is located between the positive and negative electrodes. In the winding axis direction of the electrode assembly, the length dimension of the positive electrode can also be larger than the length dimension of the negative electrode, and the length dimension of the spacer can also be larger than the length dimension of the positive electrode.
[0019] The positive electrode can also be formed into a long strip (or strip). The positive electrode can also contain a positive electrode active material. The positive electrode active material can be any material used in the positive electrodes of primary and secondary batteries. For example, manganese dioxide, fluorinated graphite, iron sulfide, lithium manganese oxide, etc., can be used. The positive electrode may have, for example, a positive electrode current collector and a positive electrode binder layer containing the positive electrode active material.
[0020] Materials used as the positive current collector can include stainless steel, metals containing Al and / or Ti, etc. For stainless steel, highly corrosion-resistant materials such as SUS444 and SUS316 are preferred. Metals containing Al and / or Ti can also be alloys. For example, sheets or porous materials can be used as the positive current collector. Metal foil can also be used. Furthermore, as porous positive current collectors, metal mesh (or mesh-like structures), expanded metal plates, perforated metal plates, etc., can also be used.
[0021] In addition to the positive electrode active material, the positive electrode binder constituting the positive electrode binder layer may also include binders and / or conductive agents as any component. Examples of binders include fluoropolymers, polyacrylonitrile, polyimide resins, acrylic resins, polyolefin resins, and rubber-like polymers. Examples of fluoropolymers include polytetrafluoroethylene and polyvinylidene fluoride. The positive electrode binder may contain one type of binder or more than two types.
[0022] Carbon materials are preferred as conductive agents. Examples of carbon materials include carbon black (acetylene black, Ketjen black, etc.), carbon nanotubes, and graphite. The positive electrode mixture may also contain one or more conductive agents. The conductive agent may also exist between the positive electrode current collector and the positive electrode mixture layer.
[0023] The manufacturing method of the positive electrode is not particularly limited. For example, the positive electrode can be obtained by attaching a positive electrode compound to a positive electrode current collector. For instance, the positive electrode compound can be coated onto the positive electrode current collector, or it can be filled into a porous positive electrode current collector. Furthermore, the positive electrode compound can be formed into sheets and laminated to physically contact the positive electrode current collector. During the manufacturing of the positive electrode, the positive electrode compound, as needed, may be used in a paste or clay-like form, in addition to its constituent components, a dispersant (e.g., water and / or an organic medium). At appropriate stages of the positive electrode manufacturing process, drying and compression (rolling, etc.) in the thickness direction of the positive electrode may be performed as needed.
[0024] The negative electrode can also be formed in the form of a long strip (or a strip). The negative electrode can also contain metallic lithium, a lithium alloy, or a lithium alloy. Examples of lithium alloys include materials containing at least one of Ca, Mg, Al, Si, Zn, Sn, and Pb. The content of metal elements other than lithium in the lithium alloy is preferably 0.01% by mass or more and 1.0% by mass or less relative to the metal element alloying with lithium. It should be noted that metallic lithium can also contain less than 0.01% by mass of elements other than lithium.
[0025] As a sheet-like negative electrode, it can be made of lithium metal foil or a sheet containing a composite of lithium metal and a lithium alloy. The lithium alloy in the composite can also be dispersed in the lithium metal in a particulate form. The sheet-like negative electrode can be formed, for example, by extruding lithium metal, a lithium alloy, or lithium metal and a lithium alloy. The lithium alloy can also be formed by alloying the surface layer of the lithium metal foil with an aluminum lattice or similar material.
[0026] The spacer can be a porous sheet material with ion permeability and insulation. Examples of porous sheets include microporous membranes, woven fabrics, and nonwoven fabrics. The spacer can be a single-layer structure or a multi-layer structure. Examples of multi-layer spacers include spacers comprising multiple layers with different materials and / or structures.
[0027] The material used for the spacer is not specifically limited, but it can also be a polymer material. Examples of polymer materials include olefin resins (polyethylene, polypropylene, and copolymers of ethylene and propylene, etc.), polyamide resins, polyimide resins (polyimide, polyamide-imide, etc.), cellulose, polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE). The spacer may also contain additives as needed. Examples of additives include inorganic fillers.
[0028] The thickness of the spacer can be selected, for example, from a range of 10 μm or more and 200 μm or less. When the spacer is made of a microporous membrane, the thickness of the spacer is, for example, 10 μm or more and 80 μm or less, preferably 20 μm or more and 70 μm or less.
[0029] The casing is formed into a bottomed cylindrical shape (e.g., a bottomed cylindrical or bottomed square prism) to house the electrode assembly and electrolyte. The casing is electrically connected to the positive electrode of the electrode assembly. Therefore, the casing functions as the external positive terminal of the primary battery. The casing can be made of, for example, iron, iron alloys (SUS, etc.), aluminum, aluminum alloys (aluminum alloys containing trace amounts of manganese, copper, and other metals), and may be plated as needed. The electrolyte can also be a non-aqueous electrolyte.
[0030] As a non-aqueous electrolyte, materials with lithium-ion conductivity can also be used. Such a non-aqueous electrolyte comprises a non-aqueous solvent and a lithium salt as an electrolyte dissolved in the non-aqueous solvent. The non-aqueous electrolyte is prepared by dissolving the lithium salt in the non-aqueous solvent.
[0031] While lithium salts are materials used in non-aqueous electrolytes for primary lithium batteries, their use is not particularly restricted. Examples of lithium salts include lithium borofluoride, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium perchlorate. Non-aqueous electrolytes may contain one or more lithium salts.
[0032] Examples of non-aqueous solvents include, but are not limited to, esters (such as carbonates, γ-butyrolactone, and other carboxylic acid esters) and ethers (such as 1,2-dimethoxyethane). Examples of carbonates include cyclic carbonates (propylene carbonate, ethylene carbonate, etc.) and chain carbonates (diethyl carbonate, methyl ethyl carbonate, etc.). Non-aqueous electrolytes may also contain one or more non-aqueous solvents.
[0033] The concentration of lithium salt in the non-aqueous electrolyte is, for example, above 0.1 mol / L and below 3.5 mol / L.
[0034] Non-aqueous electrolytes may also contain additives as needed. Examples of additives include vinylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, phthalic anhydride, and succinic anhydride. One additive may be used alone, or two or more may be used in combination.
[0035] The sealing body seals the opening of the housing. The sealing body may also include: a conductive sealing plate welded to the opening edge of the housing; a conductive external terminal disposed in the opening formed in the center of the sealing plate; and an insulating gasket between the two. In this case, the negative lead may also be connected to the external terminal. Alternatively, the sealing body has at least one conductive member, and the opening edge of the housing may be riveted to the periphery of the sealing body via an insulating gasket. In this case, the negative lead may also be connected to at least one conductive member.
[0036] The negative electrode lead has a first main surface connected to the negative electrode and a second main surface on its opposite side. The negative electrode lead protrudes from the first end face of the electrode assembly, electrically connecting the negative electrode to the sealing body. Therefore, the sealing body functions as the external terminal of the negative electrode of the primary battery. The negative electrode lead can also be formed in a strip (or ribbon). The negative electrode lead can also be made of metal foil. The material of this metal foil can be, for example, nickel (Ni), Ni alloys, copper (Cu), Cu alloys, iron (Fe), Fe alloys, SUS, etc. Additionally, double-layer composite materials such as Ni / Cu, Ni / Fe, Ni / SUS, Cu / SUS, etc., and triple-layer composite materials such as Ni / Fe / Ni, Ni / Cu / Ni, SUS / Cu / SUS, Ni / SUS / Ni, etc., can also be used.
[0037] The first electrolyte shielding portion has an intervening portion between the first main surface of the negative electrode lead and the end face of the negative electrode. The first electrolyte shielding portion covers a portion of the first main surface and a portion of the second main surface of the negative electrode lead. The first electrolyte shielding portion may also cover a portion of the side surface of the negative electrode lead that connects the first main surface and the second main surface. The first electrolyte shielding portion is preferably made of a material with high insulation and heat resistance, preferably including polyimide, polyamide, polyamide-imide, etc. Among them, polyimide, fully aromatic polyamide (aramid), etc. are preferred, and polyimide is particularly preferred. When the first electrolyte shielding portion includes polyimide, the first electrolyte shielding portion may also include materials other than polyimide (e.g., polyolefin, polytetrafluoroethylene), and may also be made of a polymer alloy of polyimide and resins other than polyimide. The first electrolyte shielding portion may also be made of, for example, an electrolyte shielding tape or an electrolyte shielding coating containing these materials. The thickness of the first electrolyte shielding portion can be, for example, 7 μm or more and 700 μm or less.
[0038] The first electrolyte shielding portion extends across the end of the positive electrode on the first end face side in the winding axis direction of the electrode assembly. In other words, in this winding axis direction, the end of the positive electrode is located between one end and the other end of the first electrolyte shielding portion. In other words, the negative electrode lead is covered by the first electrolyte shielding portion in the area opposite to the end of the positive electrode. In addition, as mentioned above, the first electrolyte shielding portion has an intervening portion between the first main surface of the negative electrode lead and the end of the negative electrode on the first end face side. Here, in the non-aqueous electrolyte battery of Patent Document 1, the electrolyte shielding member 9 shown in the figures of that document does not have such an intervening portion. Therefore, in this battery, during over-discharge, the non-aqueous electrolyte seeps into the gap between the electrolyte shielding member 9 and the negative electrode plate 4 and the negative electrode current collector 8 (in that document). Figure 2 In the above-described mechanism, a gap (shown in a roughly triangular shape in the region opposite the end of the positive electrode) may generate heat. In contrast, the first electrolyte shielding portion of this disclosure, having an intervening portion and extending across the end of the positive electrode, prevents the electrolyte from contacting the negative electrode lead in the region where the first electrolyte shielding portion is disposed (or, the region opposite the end of the negative electrode lead to the positive electrode), thereby suppressing the heat generated according to the above-described mechanism. The distance in the winding axis direction between one end of the first electrolyte shielding portion (e.g., the end on the first end face side) and the end on the first end face side of the positive electrode may, for example, be 1 mm or more and 30 mm or less. The distance in the winding axis direction between the other end of the first electrolyte shielding portion (e.g., the end on the second end face side or the end of the intervening portion) and the end on the first end face side of the positive electrode may, for example, be 1 mm or more and 30 mm or less. By setting the distance between the two ends of the first electrolyte shielding portion and the end on the first end face side of the positive electrode in this way, the heat suppression effect during over-discharge can be further improved.
[0039] The first electrolyte shielding portion can also extend across and across the end of the first end face of the spacer in the winding axis direction of the electrode assembly. In other words, in this winding axis direction, the end of the first end face of the spacer (and the end of the first end face of the positive electrode) can also be located between one end and the other end of the first electrolyte shielding portion. The end of the first end face of the spacer is located further outward in the winding axis direction than the end of the first end face of the positive electrode, so according to this structure, a wider area of the negative electrode lead is covered by the first electrolyte shielding portion. Therefore, electrolyte penetration is further suppressed, and thus heat generation during over-discharge is further suppressed.
[0040] The primary battery may also include a second electrolyte shielding portion disposed on the second main surface side of the negative electrode lead and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode lead. The second electrolyte shielding portion may also cover the connection between the negative electrode lead and the negative electrode when viewed from the normal direction of the second main surface. The material of the second electrolyte shielding portion may be selected from the materials exemplified as the material of the first electrolyte shielding portion, and may be the same as or different from the material of the first electrolyte shielding portion. A portion of the first electrolyte shielding portion may be the portion of the second main surface of the first electrolyte shielding portion that covers the negative electrode lead, and may be partially or entirely covered by the second electrolyte shielding portion. A portion of the negative electrode lead may also include a portion of the negative electrode lead that protrudes further towards the electrode assembly side than the first electrolyte shielding portion (hereinafter also referred to as the protrusion portion), and may be partially or entirely covered by the second electrolyte shielding portion. The electrical connection between the negative electrode lead and the negative electrode may also be formed, for example, by crimping, ultrasonic welding, etc. Since this connection portion cannot be covered by the first electrolyte shielding portion, without any measures, the portion corresponding to the connection portion in the negative electrode lead (or the aforementioned protrusion) may be etched and deposited during over-discharge. In contrast, in this structure, when viewed from the normal direction of the second main surface, the connection portion is covered by the second electrolyte shielding portion, thus suppressing the etching and deposition of a portion of the negative electrode lead during over-discharge. The thickness of the second electrolyte shielding portion can, for example, be 7 μm or more and 700 μm or less.
[0041] The primary battery may also include a third electrolyte shielding portion, disposed on the first main surface side of the negative electrode lead, and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode. Viewed from the normal direction of the first main surface, the third electrolyte shielding portion may also cover the connection portion between the negative electrode lead and the negative electrode. The material of the third electrolyte shielding portion may be selected from the materials exemplified as the material of the first electrolyte shielding portion, and may be the same as or different from the material of the first electrolyte shielding portion. A portion of the first electrolyte shielding portion may also be the portion of the first electrolyte shielding portion covering the first main surface of the negative electrode lead, and this portion, or all of it, may also be covered by the third electrolyte shielding portion. A portion of the negative electrode may also be the portion of the negative electrode opposite to the aforementioned protrusion, and this opposing portion, or all of it, may also be covered by the third electrolyte shielding portion. As described above, the portion of the negative electrode lead corresponding to the connection portion may be dissolved and deposited during over-discharge. In contrast, in this structure, when viewed from the normal direction of the first main surface, the connection portion is covered by a third electrolyte shielding portion, thus suppressing the dissolution and precipitation of a portion of the negative electrode lead during over-discharge. This suppression effect is particularly significant when the primary battery has both a second electrolyte shielding portion and a third electrolyte shielding portion. The thickness of the third electrolyte shielding portion can, for example, be 7 μm or more and 700 μm or less.
[0042] The first electrolyte shielding portion can also be composed of an electrolyte shielding strip wound around the negative electrode lead. In this case, one electrolyte shielding strip can cover the first main surface, the second main surface, and the side surface of the negative electrode lead. Besides reducing the number of components used to form the first electrolyte shielding portion to one, it is sufficient to position one electrolyte shielding strip relative to the negative electrode lead, thus making it easy to form the first electrolyte shielding portion. It should be noted that although this effect may be weakened, two or more electrolyte shielding strips can still be wound around the negative electrode lead. Furthermore, the first electrolyte shielding portion can also be composed of multiple electrolyte shielding strips adhered to the negative electrode lead from the first main surface side and the second main surface side.
[0043] As described above, according to this disclosure, by covering a predetermined portion of the negative electrode lead with a first electrolyte shielding portion having an intervention portion, it is possible to suppress the heating of the primary battery during over-discharge.
[0044] Hereinafter, an example of a primary battery according to the present disclosure will be specifically described with reference to the accompanying drawings. The above-described constituent elements can be applied to the constituent elements of the primary battery of the example described below. The constituent elements of the primary battery of the example described below can be modified based on the above description. Furthermore, the matters described below can also be applied to the above-described embodiments. Non-essential constituent elements of the primary battery according to the present disclosure in the constituent elements of the primary battery of the example described below can be omitted. It should be noted that the figures shown below are schematic and do not accurately reflect the actual shape and number of components.
[0045] Implementation Method 1
[0046] Embodiment 1 of this disclosure will be described. For example... Figure 1 and Figure 2 As shown, the primary battery 10 of this embodiment includes an electrode assembly 20, a housing 30, a sealing body 40, a negative electrode lead 60, a first electrolyte shielding portion 71, and a second electrolyte shielding portion 72. To prevent internal short circuits, an upper insulating plate 81 and a lower insulating plate 82 are respectively disposed on the upper and lower parts of the electrode assembly 20.
[0047] Electrode assembly 20 has a positive electrode 21, a negative electrode 22, and a spacer 23 between them, and has a first end face ( Figure 1 The upper end face and the second end face on the opposite side (in the middle) Figure 1 The electrode assembly 20 is a spiral-wound electrode assembly (located at the lower end face of the electrode). The electrode assembly 20 is constructed by spirally winding a strip-shaped positive electrode 21 and a strip-shaped negative electrode 22, separated by a strip-shaped spacer 23. The positive electrode 21 has a positive electrode active material (manganese dioxide in this example). The negative electrode 22 is made of a consumable metal (lithium metal in this example). The spacer 23 is made of a microporous membrane made of polyolefin. The winding axis direction of the electrode assembly 20 (…) Figure 1 In the vertical direction, the length of the positive electrode 21 is larger than that of the negative electrode 22, and the length of the spacer 23 is larger than that of the positive electrode 21.
[0048] The housing 30 is formed into a bottomed cylindrical shape, housing the electrode assembly 20 and a non-aqueous electrolyte (not shown). The housing 30 is made of an iron alloy (SUS in this example). The housing 30 is electrically connected to the positive electrode 21 of the electrode assembly 20 via a positive lead 50. Therefore, the housing 30 functions as the external positive terminal of the primary battery 10. One end of the positive lead 50 can also be connected to the positive electrode 21 by welding or the like. The other end of the positive lead 50 can also be connected to the inner bottom surface of the housing 30 by welding or the like. The non-aqueous electrolyte is an example of an electrolyte.
[0049] The sealing body 40 seals the opening of the housing 30. The sealing body 40 includes: a conductive sealing plate 41 that contacts the opening edge of the housing 30; a conductive external terminal 42 disposed in the opening formed in the center of the sealing plate 41; and an insulating gasket 43 between the two. As described later, the external terminal 42 is electrically connected to the negative terminal 22 of the electrode assembly 20 via the negative lead 60. Therefore, the external terminal 42 functions as the negative external terminal of the primary battery 10.
[0050] The negative electrode lead 60 has a first main surface 61 connected to the negative electrode 22, a second main surface 62 opposite to the first main surface 61, and a side surface 63 connecting the two. The negative electrode lead 60 is made of a strip of metal foil. The negative electrode lead 60 protrudes from the first end face of the electrode assembly 20, thereby electrically connecting the negative electrode 22 of the electrode assembly 20 and the external terminal 42 of the sealing body 40. One end of the negative electrode lead 60 can also be connected to the negative electrode 22 by welding or the like. The other end of the negative electrode lead 60 can also be connected to the external terminal 42 of the sealing body 40 by welding or the like. It should be noted that... Figure 2 In the middle, the connection J between the negative lead 60 and the negative electrode 22 is shown with a thick cross (×).
[0051] The first electrolyte shielding portion 71 covers a portion of the first main surface 61, a portion of the second main surface 62, and a portion of the side surface 63 of the negative electrode lead 60. At least a portion (e.g., more than 80%) of the first main surface 61, the second main surface 62, and the side surface 63 repeat each other in the winding axis direction of the electrode assembly 20. The first electrolyte shielding portion 71 has an intervening portion 71a between the first main surface 61 of the negative electrode lead 60 and the end portion 22a of the first end face side of the negative electrode 22. The first electrolyte shielding portion 71 is composed of an electrolyte shielding strip wound onto the negative electrode lead 60. The electrolyte shielding strip contains polyimide. The electrolyte shielding strip is wound onto the negative electrode lead 60 in a direction orthogonal to the winding axis direction of the electrode assembly 20.
[0052] The first electrolyte shielding part 71 extends across the first end face side of the positive electrode 21 in the winding axis direction of the electrode assembly 20. Figure 2 The upper end of the electrode assembly 20 extends beyond the first end face side of the spacer 23 in the winding axis direction of the electrode assembly 20. Figure 2 (the upper part of the middle) and extends.
[0053] The second electrolyte shielding part 72 is provided on the side of the second main surface 62 of the negative electrode lead 60. Figure 2 (a) on the left side), and covering a portion of the first electrolyte shielding portion 71 and a portion of the negative electrode lead 60. Figure 2As shown in (b), the second electrolyte shielding portion 72, viewed from the normal direction of the second main surface 62, covers the connection portion J between the negative electrode lead 60 and the negative electrode 22. Viewed from the normal direction of the second main surface 62, the second electrolyte shielding portion 72 covers the portion of the negative electrode lead 60 that is further towards the electrode assembly 20 than the first electrolyte shielding portion 71. Figure 2 The portion protruding from the lower side of the first electrolyte shielding portion 71. Viewed from the normal direction of the second main surface 62, the second electrolyte shielding portion 72 covers the first electrolyte shielding portion 71. The second electrolyte shielding portion 72 is composed of an electrolyte shielding strip that is attached across the negative electrode lead 60 and the first electrolyte shielding portion 71. The electrolyte shielding strip contains polyimide.
[0054] Implementation Method 2
[0055] Embodiment 2 of this disclosure will be described. The primary battery 10 of this embodiment differs from that of Embodiment 1 described above in that it includes a third electrolyte shielding portion 73. Hereinafter, the differences from Embodiment 1 will be mainly described.
[0056] like Figure 3 As shown, the primary battery 10 of this embodiment includes a third electrolyte shielding portion 73. The third electrolyte shielding portion 73 is provided on the first main surface 61 side of the negative electrode lead 60. Figure 3 (a) on the right side), and covering the bottom of the first electrolyte shielding part 71 and a portion of the negative electrode 22. Figure 3 As shown in (b), the third electrolyte shielding portion 73, viewed from the normal direction of the first main surface 61, covers the connection portion J between the negative electrode lead 60 and the negative electrode 22. Viewed from the normal direction of the first main surface 61, the third electrolyte shielding portion 73 covers the portion of the negative electrode lead 60 that protrudes further towards the electrode assembly 20 than the first electrolyte shielding portion 71. Viewed from the normal direction of the first main surface 61, the third electrolyte shielding portion 73 covers the first electrolyte shielding portion 71. The third electrolyte shielding portion 73 is composed of an electrolyte shielding strip that is bonded throughout the negative electrode lead 60, the first electrolyte shielding portion 71, and the negative electrode 22. The electrolyte shielding strip contains polyimide.
[0057] Implementation Method 3
[0058] Embodiment 3 of this disclosure will be described. For example... Figure 4 As shown, the primary battery 10 of this embodiment does not have a second electrolyte shielding portion 72. Other structures are the same as those in Embodiment 1 described above.
[0059] Postscript
[0060] Based on the description of the above embodiments, the following technology is disclosed.
[0061] (Technology 1)
[0062] A primary battery having:
[0063] A wound electrode assembly has a positive electrode, a negative electrode made of consumable metal, and a spacer between the positive electrode and the negative electrode, and has a first end face and a second end face on the opposite side.
[0064] Electrolyte;
[0065] A cylindrical shell is provided to house the electrode assembly and the electrolyte, and is electrically connected to the positive electrode.
[0066] A sealing body, used to seal the opening of the shell;
[0067] A negative lead has a first main surface connected to the negative electrode and a second main surface opposite to it, protruding from the first end face to electrically connect the negative electrode and the sealing body; and
[0068] The first electrolyte shielding portion has an intervening portion located between the first main surface of the negative electrode lead and the end of the negative electrode on the first end face side, and covers a portion of the first main surface and a portion of the second main surface.
[0069] The first electrolyte shielding portion extends across the end of the positive electrode on the first end face side in the direction of the winding axis of the electrode assembly.
[0070] (Technology 2)
[0071] According to the primary battery described in Technology 1, wherein,
[0072] The first electrolyte shielding portion extends across the end of the first end face side of the spacer in the direction of the winding shaft.
[0073] (Technology 3)
[0074] According to technology 1 or 2, in the primary battery, wherein...
[0075] The primary battery further comprises: a second electrolyte shielding portion disposed on the second main surface side of the negative electrode lead, and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode lead.
[0076] The second electrolyte shielding portion, when viewed from the normal direction of the second main surface, covers the connection between the negative electrode lead and the negative electrode.
[0077] (Technology 4)
[0078] According to the primary battery described in Technology 3, wherein...
[0079] The primary battery further comprises: a third electrolyte shielding portion disposed on the first main surface side of the negative electrode lead, and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode.
[0080] The third electrolyte shielding portion, viewed from the normal direction of the first main surface, covers the connection portion between the negative electrode lead and the negative electrode.
[0081] (Technology 5)
[0082] The primary battery according to any one of techniques 1 to 4, wherein...
[0083] The first electrolyte shielding portion is composed of an electrolyte shielding strip wound around the negative electrode lead.
[0084] Example
[0085] Regarding the batteries of Examples 1-3 and Comparative Examples 1 and 2 shown below, their behavior during over-discharge was evaluated. Specifically, for each battery, after discharging only 95% of its rated capacity, a constant current scan of 50mA was performed, and the voltage was switched to a constant voltage scan after rising to 4V. These constant current and constant voltage scans (i.e., battery over-discharge) were performed at an ambient temperature of 25°C. In addition, except for Example 2, which did not experience over-discharge, over-discharge continued until 3200mAh of capacity was discharged. Furthermore, the highest temperature reached by the casing during over-discharge and the presence or absence of dissolution of the casing and negative electrode leads were evaluated.
[0086] Example 1
[0087] A primary battery of the type shown in Embodiment 1, namely a battery having first and second electrolyte shielding portions and a positively polarized casing, was evaluated. The highest temperature reached by the casing during over-discharge was 25°C, and no substantial heating was observed. Furthermore, there was no dissolution of the casing during over-discharge, and only slight dissolution was observed in the protrusion of the negative electrode lead that was not covered by the first electrolyte shielding portion.
[0088] Example 2
[0089] A primary battery of the type shown in Embodiment 2 above, namely a primary battery having first to third electrolyte shielding portions and a positively polarized casing, was evaluated. The highest temperature reached by the casing during over-discharge was 25°C, and no heat generation was substantially observed. Furthermore, there was no dissolution of the casing or the negative electrode lead during over-discharge. In particular, in the primary battery of this embodiment, over-discharge itself did not occur during constant voltage scanning.
[0090] Example 3
[0091] A battery of the type shown in Embodiment 3 above, namely a primary battery having a first electrolyte shielding portion and a positively polarized casing, was evaluated. The highest temperature reached by the casing during over-discharge was 25°C, and no substantial heating was observed. Furthermore, there was no dissolution of the casing during over-discharge, and only the protrusion of the negative electrode lead not covered by the first electrolyte shielding portion dissolved.
[0092] Comparative Example 1
[0093] A battery of the type disclosed in Patent Document 1, namely a primary battery without a first electrolyte shielding portion and with a positively polarized casing, was evaluated. The highest temperature reached by the casing during over-discharge was higher than 25°C, and heat generation was observed. Furthermore, although there was no dissolution of the casing during over-discharge, most of the negative electrode leads dissolved.
[0094] Comparative Example 2
[0095] A secondary battery having components equivalent to the first to third electrolyte shielding portions and a negatively polarized casing (i.e., the casing is electrically connected to the negative electrode of the electrode assembly via a negative electrode lead) was evaluated. The highest temperature reached by the casing during over-discharge was higher than 25°C, and heating was observed. Furthermore, a portion of the casing dissolved during over-discharge, and most of the negative electrode lead dissolved as well.
[0096] As described above, the primary batteries of each embodiment did not exhibit heat generation during over-discharge compared to the primary or secondary batteries of the comparative examples, and the degree of dissolution of the negative electrode leads was also less. Therefore, it can be said that the advantages of each embodiment have been verified.
[0097] Industrial applicability
[0098] This disclosure can be used in primary batteries.
[0099] Explanation of reference numerals in the attached figures
[0100] 10: Primary batteries
[0101] 20: Electrode assembly
[0102] 21: Positive electrode
[0103] 21a: End
[0104] 22: Negative electrode
[0105] 22a: End
[0106] 23: Spacer
[0107] 23a: End
[0108] 30: Shell
[0109] 40: Sealing body
[0110] 41: Sealing plate
[0111] 42: External terminal
[0112] 43: Washer
[0113] 50: Positive lead
[0114] 60: Negative lead
[0115] 61: First Main Page
[0116] 62: Second Main Face
[0117] 63: Side view
[0118] 71: First electrolyte shielding section
[0119] 71a: Interventional Department
[0120] 72: Second electrolyte shielding section
[0121] 73: Third electrolyte shielding section
[0122] 81: Upper Insulation Board
[0123] 82: Lower insulation board
[0124] J: Connecting part.
Claims
1. A primary battery, comprising: A wound electrode assembly has a positive electrode, a negative electrode made of consumable metal, and a spacer between the positive electrode and the negative electrode, and has a first end face and a second end face on the opposite side. Electrolyte; A bottomed cylindrical shell houses the electrode assembly and the electrolyte, and is electrically connected to the positive electrode; A sealing body, used to seal the opening of the shell; A negative lead has a first main surface connected to the negative electrode and a second main surface opposite to it, protruding from the first end face to electrically connect the negative electrode and the sealing body; and The first electrolyte shielding portion has an intervening portion located between the first main surface of the negative electrode lead and the end of the negative electrode on the first end face side, and covers a portion of the first main surface and a portion of the second main surface. The first electrolyte shielding portion extends across the end of the positive electrode on the first end face side in the direction of the winding axis of the electrode assembly.
2. The primary battery according to claim 1, wherein, The first electrolyte shielding portion extends across the end of the first end face side of the spacer in the direction of the winding shaft.
3. The primary battery according to claim 1 or 2, wherein, The primary battery further comprises: a second electrolyte shielding portion disposed on the second main surface side of the negative electrode lead, and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode lead. The second electrolyte shielding portion, when viewed from the normal direction of the second main surface, covers the connection between the negative electrode lead and the negative electrode.
4. The primary battery according to claim 3, wherein, The primary battery further comprises: a third electrolyte shielding portion disposed on the first main surface side of the negative electrode lead, and covering a portion of the first electrolyte shielding portion and a portion of the negative electrode. The third electrolyte shielding portion, viewed from the normal direction of the first main surface, covers the connection portion between the negative electrode lead and the negative electrode.
5. The primary battery according to claim 1 or 2, wherein, The first electrolyte shielding portion is composed of an electrolyte shielding strip wound around the negative electrode lead.