Coin cell

Abstract

A disclosed battery includes a laminate of positive electrode plates, negative electrode plates, and separators. The separators include a plurality of repeating units S aligned in a row along a direction (Ds) orthogonal to a width direction (WDs) thereof. The separators include an end portion folded with the positive current collector at a boundary between the positive current collector and a positive lead portion and laminated with a portion of the positive lead portion and / or an end portion folded with the negative current collector at a boundary between the negative current collector and a negative lead portion and laminated with a portion of the negative lead portion. When a length of the repeating unit S in the direction (Ds) is Ls, a length of the end portion (60p) in the direction (Ds) and a length of the end portion (60n) in the direction (Ds) are each in a range of 0.3Ls to 0.7Ls.

Description

Technical Field

[0001] This invention relates to coin-shaped batteries. Background Technology

[0002] In the past, coin-shaped batteries were used as power sources for various electronic devices. Among coin-shaped batteries, those using electrodes bent into a zigzag shape are known.

[0003] Patent document 1 discloses "an electrochemical unit, characterized in that the electrochemical unit comprises: a positive electrode; a negative electrode having a negative current collector exposed portion; and a separator disposed between the positive electrode and the negative electrode, the positive electrode having a bent portion that is bent in such a way that it clamps the negative electrode through the separator and is opposite to the negative current collector exposed portion, and an ion-proof portion that prevents ions from passing through is provided between the negative current collector exposed portion and the bent portion."

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-162777 Summary of the Invention

[0007] Coin-shaped batteries are typically small in size, making them difficult to fill with electrolyte and assemble. Therefore, for coin-shaped batteries, there is a need to improve the yield and manufacturing efficiency. Under these circumstances, one of the objectives of this invention is to provide a coin-shaped battery that can be manufactured with good yield and efficiency.

[0008] One technical solution of the present invention relates to a coin-shaped battery. The coin-shaped battery includes a laminate formed by bending a positive electrode plate, a negative electrode plate, and a separator in a zigzag shape such that the separator is disposed between the positive and negative electrode plates. The positive electrode plate includes: a positive current collector, comprising a positive current collector portion and a positive lead portion connected to the positive current collector portion, the positive current collector portion comprising a plurality of repeating units P arranged in a row; and a positive active material layer disposed on the plurality of repeating units P. The negative electrode plate includes: a negative current collector, comprising a negative current collector portion and a negative lead portion connected to the negative current collector portion, the negative current collector portion comprising a plurality of repeating units N arranged in a row; and a negative active material layer disposed on the plurality of repeating units N. The separator comprises a plurality of repeating units S arranged in a row along a direction Ds orthogonal to its width direction WDs. In the laminate, the positive current collector, the negative electrode... The current collector and the separator are bent at their respective bends in a manner in which the plurality of repeating units P, the plurality of repeating units N, the plurality of repeating units S, the positive lead portion, and the negative lead portion are stacked. The separator includes at least one end selected from the group consisting of an end SP and an end SN. The end SP is bent together with the positive current collector at the boundary between the positive current collector and the positive lead portion and is stacked with a portion of the positive lead portion. The end SN is bent together with the negative current collector at the boundary between the negative current collector and the negative lead portion and is stacked with a portion of the negative lead portion. When the length of the repeating unit S in the direction Ds is set to Ls, the lengths of the end SP and the end SN in the direction Ds are respectively in the range of 0.3Ls to 0.7Ls.

[0009] According to the present invention, it is possible to obtain coin-shaped batteries that can be manufactured with good yield and efficiency. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view schematically illustrating an example of the coin-shaped battery of the present invention.

[0011] Figure 2 This is a cross-sectional view schematically illustrating an example of a laminate (plate assembly) used in the coin-shaped battery of the present invention.

[0012] Figure 3A It is a schematic representation Figure 1 The top view of the unfolded state of the stacked body shown.

[0013] Figure 3B It is a schematic representation Figure 3A A cross-sectional view at line IIIB-IIIB.

[0014] Figure 3C It is a schematic representation Figure 1 A top view of the constituent components of the stacked body shown.

[0015] Figure 4 It is a schematic representation Figure 2 A top view of the configuration of the stacked bodies shown.

[0016] Figure 5A This is a top view schematically illustrating another example of the laminated structure used in the coin-shaped battery of the present invention.

[0017] Figure 5B It is used for explanation Figure 5A A schematic diagram of the configuration of the stacked bodies shown. Detailed Implementation

[0018] The following examples illustrate embodiments of the present invention. However, the present invention is not limited to the examples described below. In the following description, specific values ​​and materials are sometimes illustrated, but other values ​​and materials can be applied as long as the effects of the present invention can be obtained. In this specification, the references "value A to value B" include both value A and value B, and can be replaced with "value A or higher and value B or lower".

[0019] Hereinafter, the coin-shaped battery of this embodiment will sometimes be referred to as "battery (B)". Battery (B) comprises a laminate formed by bending a positive electrode plate, a negative electrode plate, and a separator in a zigzag shape, with the separator disposed between the positive and negative electrode plates. The positive electrode plate includes: a positive current collector comprising a positive current collector portion and a positive lead portion connected to the positive current collector portion, the positive current collector portion comprising a plurality of repeating units P arranged in a row; and a positive active material layer disposed on the plurality of repeating units P. The negative electrode plate includes: a negative current collector comprising a negative current collector portion and a negative lead portion connected to the negative current collector portion, the negative current collector portion comprising a plurality of repeating units N arranged in a row; and a negative active material layer disposed on the plurality of repeating units N. The separator comprises a plurality of repeating units S arranged in a row along a direction Ds orthogonal to its width direction WDs.

[0020] In the laminate, the positive current collector, the negative current collector, and the separator are bent at their respective bends in a manner that involves stacking multiple repeating units P, multiple repeating units N, multiple repeating units S, a positive lead portion, and a negative lead portion. The separator includes at least one end selected from the group consisting of an end SP and an end SN. The end SP is bent together with the positive current collector at the boundary between the positive current collector and the positive lead portion and is stacked with a portion of the positive lead portion. The end SN is bent together with the negative current collector at the boundary between the negative current collector and the negative lead portion and is stacked with a portion of the negative lead portion. Hereinafter, this at least one end is sometimes referred to as an "end (SP / SN)". When the length of the repeating unit S in the direction Ds is set to Ls, the lengths of the end SP and the end SN in the direction Ds are both in the range of 0.3Ls to 0.7Ls. In other words, when the separator includes an end SP, the length of the end SP in the direction Ds is in the range of 0.3Ls to 0.7Ls, and when the separator includes an end SN, the length of the end SN in the direction Ds is in the range of 0.3Ls to 0.7Ls.

[0021] By providing the end portions (SP / SN), short circuits between the positive and negative plates can be suppressed. As a result, the yield during manufacturing can be improved. By making the length of the end portions (SP / SN) 0.3Ls or more, electrolyte injection becomes easier, improving manufacturing efficiency. Furthermore, by making this length 0.3Ls or more, short circuits between the positive and negative plates can be suppressed. Additionally, by making this length 0.7Ls or less, electrolyte injection becomes easier, and electrolyte leakage caused by excessive clamping of the separator between the casing body and the gasket can be suppressed. In other words, by making the length of the end portions (SP / SN) 0.7Ls or less, a decrease in yield during manufacturing can be suppressed. Coin-shaped batteries are typically small in size, making electrolyte injection and assembly difficult. However, using the structure of this embodiment, as shown in the example, good yield and efficiency can be achieved during manufacturing.

[0022] The separator may include only the end SP, only the end SN, or both the end SP and the end SN. By including both the end SP and the end SN, short circuits between the positive and negative plates can be suppressed in particular. When assembling the battery, if the electrolyte is injected from the casing body side (or, from another viewpoint, the opening side of the sealing plate with a container shape), it is preferable that the separator has the end of the lead portion of the current collector stacked on the side connected to the casing body. In a typical coin-shaped battery, the casing body is connected to the positive electrode. Therefore, it is preferable that the separator includes at least the end SP. The battery (B) may also satisfy the following condition (1).

[0023] (1) The separator includes end SP. The separator may also include end SP and end SN.

[0024] Repeating units P are connected in a row along direction Dp, which is orthogonal to the width direction WDp of the positive current collector. Repeating units N are connected in a row along direction Dn, which is orthogonal to the width direction WDn of the negative current collector.

[0025] The lead portion has a length sufficient to form an end (SP / SN). For example, in the direction Dp where the repeating unit P is connected, the length of the positive electrode lead portion is longer than the length of the end SP, typically in the range of 1 to 2 times the length Lp of the repeating unit P in the direction Dp. When the length of the positive electrode lead portion in the direction Dp exceeds 1 times the length Lp, the positive electrode lead portion includes a bend. In the direction Dn where the repeating unit N is connected, the length of the negative electrode lead portion is longer than the length of the end SN, typically in the range of 1 to 2 times the length Ln of the repeating unit N in the direction Dn. When the length of the negative electrode lead portion in the direction Dn exceeds 1 times the length Ln, the negative electrode lead portion includes a bend. Furthermore, no active material layer is formed in the lead portion.

[0026] The number of repeating units P, N, and S is not limited and can range from 2 to 30 (e.g., from 5 to 25). Their number is selected according to the battery structure.

[0027] Multiple repeating units P typically have substantially the same shape and size. The boundary between two adjacent repeating units P is bent as a bend. The repeating units P are stacked in the laminate by bending the positive current collector at the bend.

[0028] Multiple repeating units N typically have substantially the same shape and size. The boundary between two adjacent repeating units N is bent as a bend. The repeating units N are stacked in the stack by bending the negative current collector at the bend.

[0029] Multiple repeating units S typically have substantially the same shape and size. The boundary between two adjacent repeating units S is bent as a bend. The repeating units S are stacked in the laminate by bending the spacers at the bends.

[0030] Furthermore, the lengths Ls in the direction Ds of the multiple repeating units S are substantially the same. Even if there are cases where the lengths Ls of the multiple repeating units S are not the same but slightly different, for all lengths Ls, it is sufficient to satisfy 0.3Ls≤(length of the end (SP / SN) in the direction Ds)≤0.7Ls.

[0031] The repeating units P and N have shapes and sizes that allow them to be housed in a flat state within the housing. On the other hand, the separator is flexible, so as long as the separator can be housed in the housing without problems, the planar shape of the repeating unit S can be slightly larger than the planar shape of the space within the housing.

[0032] The planar shapes of repeating units P, N, and S can be approximately circular, polygonal, or similar shapes. For example, the planar shape can be hexagonal, octagonal, or decagonal. The planar shape of repeating unit P is the same as or approximately the same as the planar shape of repeating unit N. Alternatively, one of them may be slightly larger than the other. In a typical example, the planar shapes of repeating unit P, repeating unit N, and repeating unit S are the same approximately circular, the same polygonal, or the same approximately polygonal. However, the size of the planar shape of repeating unit S is larger than the size of the planar shapes of repeating unit P and repeating unit N.

[0033] Repeating unit P, repeating unit N, and repeating unit S can each have a planar shape formed by adding a portion to a generally circular, polygonal, or generally polygonal shape to form a bent portion.

[0034] Alternatively, the outer edges of the positive current collector, negative current collector, and separator, especially the outer edges near the bends, can be rounded. That is, the outer edges near the bends can be formed by curves. By rounding these outer edges, stress concentration near the bends can be suppressed, preventing damage to the current collectors and separators.

[0035] The battery (B) in this embodiment can also satisfy the following condition (2).

[0036] (2) The battery (B) further includes two insulating strips that cover at least a portion of two sides of the laminate where bends are present. In this case, it is preferable that at least one end of the separator includes a portion not covered by the insulating strips. According to this structure, electrolyte can be easily injected through the portion not covered by the insulating strips, thus improving manufacturing efficiency in particular.

[0037] The battery (B) in this embodiment can also satisfy the following condition (3).

[0038] (3) The end SP extends outward in the width direction WDs compared to the repeating unit P, and the end SN extends outward in the width direction WDs compared to the repeating unit N. According to this structure, electrolyte can easily penetrate from the ends that extend outward compared to the repeating units (the ends of the separators), thus making electrolyte injection easier. As a result, manufacturing efficiency is particularly improved.

[0039] The battery (B) in this embodiment can also satisfy the following condition (4).

[0040] (4) The positive and negative lead portions are overlapped in the laminate by folding. In this case, each lead portion includes a first end portion on the collector side (positive collector side or negative collector side) and a second end portion located closer to the first end portion. The first end portion and the second end portion are connected by a bend between them. By using the second end portion as the part to be soldered to the electrode terminal, manufacturing efficiency can be improved in particular.

[0041] The battery (B) in this embodiment can also satisfy the following condition (5).

[0042] (5) At least one end (end (SP / SN)) of the separator is fixed to at least one lead portion selected from the group consisting of a positive lead portion and a negative lead portion. For example, if the separator includes an end SP, the end SP may be fixed to the positive lead portion. If the separator includes an end SN, the end SN may be fixed to the negative lead portion. By fixing the end of the separator to the lead portion, manufacturing is facilitated. There is no particular limitation on the method of fixing each end to the lead portion, and known methods can be used. For example, it can be fixed by welding or by using insulating tape.

[0043] The battery (B) in this embodiment can also satisfy the following condition (6).

[0044] (6) The first end and the second end each have the same planar shape and size as the repeating portion of the current collector to which they are located. With such a structure, the operation and processing of the current collector become easier.

[0045] An example of battery (B) preferably satisfies at least one of the conditions (1) to (6) above, or it may satisfy any two, three, four or five conditions selected from the conditions (1) to (6) above. Battery (B) may also satisfy all of the conditions (1) to (5) above, or it may satisfy all of the conditions (1) to (6) above.

[0046] The battery (B) in this embodiment can be a rechargeable secondary battery or a primary battery. The battery (B) can be a coin-shaped non-aqueous electrolyte battery or any other coin-shaped battery. The type of battery is not particularly limited as long as it is a coin-shaped battery. Examples of batteries (B) that are non-aqueous electrolyte batteries include lithium secondary batteries (lithium-ion secondary batteries, etc.) and lithium primary batteries. Examples of batteries (B) other than non-aqueous electrolyte batteries include alkaline batteries. The materials for the positive electrode active material layer, the negative electrode active material layer, the positive electrode current collector, the negative electrode current collector, the separator, and the non-aqueous electrolyte can be selected according to the type of battery. For example, materials known to be used in batteries can also be used.

[0047] The following describes a structural example of the battery (B) according to this embodiment. The structure of the battery (B) is not limited to the examples shown below, except for the structures necessary for the battery (B). Known structural components can be used for components not specifically described. The following mainly describes the case where the battery (B) is a lithium-ion secondary battery; if the battery (B) is another type of battery, the materials can be changed to match the type of battery.

[0048] The battery (B) includes a coin-shaped casing, a stack (plate assembly) disposed within the casing, and an electrolyte. The stack has the structure described above. A repeating unit S, with a positive electrode active material layer on repeating unit P and a negative electrode active material layer on repeating unit N sandwiching a separator, faces each other. A typical example of the stack includes a positive electrode plate, a negative electrode plate, and a separator, with the positive electrode active material layer disposed only on one side of the positive current collector and the negative electrode active material layer disposed only on one side of the negative current collector. However, it is also possible that active material layers are formed on both sides of the current collector of at least one of the positive and negative electrode plates. In this case, two separators may also be used. Alternatively, a bag-shaped separator formed by bonding two separators may be used to cover a repeating unit of an electrode plate. In either case, the separator includes ends (SP / SN).

[0049] When one electrode includes active material layers disposed on both sides of the current collector, a laminate can be formed by sandwiching the first electrode with two other electrodes. In this case, the active material layer can be formed only on one side of the current collector of the other electrode. For example, when active material layers are disposed on both sides of the negative electrode current collector, the electrode and the separator can be arranged in the following order: positive electrode current collector / positive electrode active material layer / separator / negative electrode active material layer / negative electrode current collector / negative electrode active material layer / separator / positive electrode active material layer / positive electrode current collector.

[0050] When both electrodes include active material layers disposed on both sides of the current collector, the laminate can be constructed such that two of the following directions—the width direction WDp of the positive current collector, the width direction WDn of the negative current collector, and the width direction WDs of the spacer—are parallel, and one direction is orthogonal to the other two directions. In an example of this laminate, repeating units P and N are stacked alternately, and repeating units S are disposed between repeating units P and N. In this case, the spacer may consist only of either end P or end N.

[0051] As mentioned above, the separator can be either bag-shaped or not. When using a non-bag-shaped separator, it is preferable to satisfy the above condition (5) in order to suppress separator offset.

[0052] Furthermore, the battery (B) of the present invention also includes a battery having a shape referred to as button-shaped. That is, a coin-shaped casing also includes the casing used in the button-shaped battery.

[0053] (Positive electrode plate)

[0054] The positive electrode plate includes a positive current collector and a positive active material layer. The positive lead portion of the positive current collector functions as a connection part that is electrically connected to a portion of the housing (housing body or sealing plate) that functions as a terminal. In this case, the connection part is connected to a portion of the housing by welding or the like. The positive current collector can be formed by processing a single sheet of metal. In this case, the positive current collector and the positive lead portion become one piece.

[0055] Examples of positive current collectors include sheet-like structures (such as foils, meshes, or stamped sheets) made of metallic materials. Examples of metallic materials constituting the positive current collector include aluminum, aluminum alloys, titanium, titanium alloys, and stainless steel. The thickness of the positive current collector can range from, for example, 5 μm to 300 μm.

[0056] The positive electrode active material layer includes the positive electrode active material, and may also include other materials (binder, conductive agent, etc.) as needed. There are no restrictions on other materials, and known materials can be used.

[0057] In the case where battery (B) is a lithium-ion secondary battery, examples of positive electrode active materials include substances capable of reversibly absorbing and releasing lithium ions. Specifically, examples of positive electrode active materials include lithium-containing metal oxides, lithium-transition metal phosphate compounds, lithium-transition metal sulfate compounds, etc. Examples of lithium-containing metal oxides include lithium transition metal composite oxides and lithium-nickel-cobalt-aluminum composite oxides, etc. Examples of lithium transition metal composite oxides include lithium-manganese composite oxides (e.g., LiMn2O4), lithium-nickel composite oxides (e.g., LiNiO2), lithium-cobalt composite oxides (e.g., LiCoO2), and composite oxides obtained by replacing a portion of these transition metal elements with other metal elements (typical metal elements and / or transition metal elements), etc.

[0058] (Negative electrode plate)

[0059] The negative electrode plate includes a negative current collector and a negative active material layer. The negative lead portion of the negative current collector functions as a connection part that is electrically connected to a portion of the housing (housing body or sealing plate) that functions as a terminal. In this case, the connection part is connected to a portion of the housing by welding or the like. The negative current collector can be formed by processing a single sheet of metal. In this case, the negative current collector and the negative lead portion become one piece.

[0060] Examples of negative current collectors include sheet-like materials (e.g., foil, mesh, or stamped sheets) made of metallic materials. Examples of metallic materials for negative current collectors include copper, nickel, iron, and alloys containing these metallic elements (copper alloys, stainless steel, etc.). In a preferred example, the metallic material of the negative current collector is copper or a copper alloy. The thickness of the negative current collector can, for example, range from 5 μm to 300 μm.

[0061] The negative electrode active material layer includes the negative electrode active material, and may also include other materials (binder, conductive agent, thickener, etc.) as needed. There are no restrictions on other materials, and known materials can be used.

[0062] In the case where battery (B) is a lithium-ion secondary battery, examples of negative electrode active materials include substances capable of reversibly absorbing and releasing lithium ions. Specifically, examples of negative electrode active materials include carbon materials, silicon, silicon compounds, and lithium alloys. Examples of carbon materials include graphite, coke, graphitized carbon, graphitized carbon fibers, and amorphous carbon.

[0063] When battery (B) is a primary lithium battery, the positive electrode active material can be manganese dioxide, etc., and the negative electrode active material can be lithium metal, etc.

[0064] (Separator)

[0065] In the example of a separator, there is a sheet that is both ion-permeable and insulating. The separator has the shape and dimensions required to insulate the positive and negative plates.

[0066] The separator can also be a microporous membrane, woven fabric, or nonwoven fabric. Examples of separator materials include insulating polymers, specifically polyolefin-based polymers, polyamide-based polymers, and cellulose-based polymers. The thickness of the separator can range from 5 μm to 200 μm.

[0067] (electrolytes)

[0068] In the case of a non-aqueous electrolyte battery, a non-aqueous electrolyte with lithium-ion conductivity can be used as the electrolyte. Typical non-aqueous electrolytes include a non-aqueous solvent, lithium ions dissolved in the non-aqueous solvent, and anions. The non-aqueous electrolyte can be liquid or a gel containing a matrix polymer. Liquid non-aqueous electrolytes can be prepared by dissolving a lithium salt in a non-aqueous solvent. Lithium ions and anions are generated by dissolving a lithium salt (a salt of lithium ions and anions) in a non-aqueous solvent. There are no particular limitations on the non-aqueous electrolyte; electrolytes used in non-aqueous electrolyte batteries can also be used.

[0069] Examples of lithium salt anions include BF4. － ClO4 － PF6 － CF3SO3 － CF3CO2 － Anions of imides, anions of oxalate complexes, etc.

[0070] Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and their halogenated derivatives (e.g., fluorides). Non-aqueous electrolytes may contain only one of these non-aqueous solvents or more than two.

[0071] Examples of esters include carbonates and carboxylic esters. Examples of cyclic carbonates include ethylene carbonate, propylene carbonate, and fluoroethylene carbonate (FEC). Examples of chain carbonates include dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate. Examples of cyclic carboxylic esters include γ-butyrolactone and γ-valerolactone. Examples of chain carboxylic esters include ethyl acetate, methyl propionate, and methyl fluoropropionate.

[0072] (case)

[0073] A typical housing includes a housing body, a sealing plate, and a gasket disposed between the housing body and the sealing plate. The housing body is a coin-shaped housing with an opening. Typically, the housing body and the sealing plate function as electrode terminals. For example, in the case of a typical coin-shaped battery, the housing body functions as the positive terminal, and the sealing plate functions as the negative terminal. The housing body and the sealing plate can be formed using metal (e.g., conductive stainless steel). Figure 1 As shown, the sealing plate may also include a circular plate-shaped portion and a cylindrical sidewall portion that rises from the outer edge of the circular plate-shaped portion.

[0074] This invention provides an example of a method for manufacturing a coin-shaped battery. The method includes: step (i), in which a laminate is formed using the aforementioned positive electrode plate, negative electrode plate, and separator; step (ii), in which two lead portions of the laminate are respectively connected to a housing body and a sealing plate with a gasket; step (iii), in which the laminate is disposed within the sealing plate with the gasket, and a non-aqueous electrolyte is disposed therein; and step (iv), in which the housing body is covered by the sealing plate with the gasket and the laminate and sealed. Through these steps, a battery (B) can be manufactured. However, the battery (B) can also be manufactured using methods other than those shown herein.

[0075] The separators used in step (i) include the aforementioned end SP and / or end SN. The laminate formed by step (i) may or may not be the same as the laminate of the battery (B). For example, in the laminate formed by step (i), the lead portion may not be laminated. Except for the case where the separators include end SP and / or end SN, there are no limitations on the manufacturing steps. Known steps can be applied, or known steps can be modified to suit the battery (B). If insulating tape is attached to the side of the laminate, the step of attaching insulating tape to the side of the laminate can be performed between step (i) and step (ii).

[0076] Alternatively, the separator can be fixed to the positive and / or negative plates before forming the laminate. For example, the separator can be fixed to the positive and / or negative lead portions. Fixing the separator facilitates the formation of the laminate. Furthermore, fixing the separator prevents separator misalignment that could lead to contact between the positive and negative plates and cause a short circuit. The method of fixing the separator is not limited; for example, welding can be used.

[0077] Process (i) can be performed as follows: flat positive electrode plate, flat negative electrode plate, and flat separator as described later. Figure 3A After overlapping as shown, bend them at the bends respectively.

[0078] Hereinafter, a battery and its manufacturing method, which are examples of the battery (B) of the present invention, will be specifically described with reference to the accompanying drawings. The constituent elements of the battery described below can be modified based on the above description. Furthermore, the matters described below can be applied to the embodiments described above. Additionally, constituent elements that are not essential to the battery (B) of the present invention can be omitted. Furthermore, for ease of understanding, the scale of the components may sometimes be changed in the following figures.

[0079] (Implementation Method 1)

[0080] exist Figure 1 The diagram schematically shows a cross-sectional view of the coin-shaped battery of Embodiment 1. Figure 1 The battery 10 includes a coin-shaped casing 20, a stack (plate assembly) 30 disposed within the casing 20, and a non-aqueous electrolyte (not shown). The casing 20 includes a bottomed cylindrical casing body 21, a sealing plate 22, and a gasket 23. The casing body 21 is closed by the sealing plate 22 and the gasket 23. As described above, the battery 10 can be a coin-shaped non-aqueous electrolyte battery, or it can be a coin-shaped battery of other types.

[0081] exist Figure 2 The diagram schematically shows a cross-sectional view of the stack 30. Figure 2 It is related to repeating unit 41ap and repeating unit 51an (see reference) Figure 3C A cross-section perpendicular to the width direction of the laminate 30. The laminate 30 includes a positive electrode plate 40, a negative electrode plate 50, and a separator 60 disposed between them. The positive electrode plate 40, the negative electrode plate 50, and the separator 60 are bent in a zigzag shape. The positive electrode active material layer 42 and the negative electrode active material layer 52 are sandwiched between the separator 60 and opposite to each other. The repeating unit 41ap of the positive electrode current collector 41, the repeating unit 51an of the negative electrode current collector 51, and the repeating unit 60s of the separator 60 (see reference) Figure 3C Stack along the stacking direction SD.

[0082] exist Figure 3A The diagram schematically shows a top view of the stacked body 30 unfolded flat. Figure 3B The diagram illustrates the meaning. Figure 3A A sectional view at line IIIB-IIIB. Additionally, in Figure 3C The middle symbol represents the meaning of making Figure 3A The top view showing the components after they have been moved and aligned along the width direction WDp of the positive current collector 41 in the indicated state. Figure 3C In the diagram, the orientation of the negative electrode 50 is reversed so that the active material layer of the negative electrode 50 can be seen. Figure 3CIn order to show the formation range of the active material layer, the areas where the positive electrode active material layer 42 and the negative electrode active material layer 52 are formed are marked with shaded lines. Additionally, in... Figure 3C In the diagram, the part that forms a bend is marked with a dashed line.

[0083] As shown in the figure, the positive electrode plate 40 includes a positive current collector 41 and a positive active material layer 42 disposed on the positive current collector 41. The positive current collector 41 includes: a positive current collector section 41a, which includes a plurality of repeating units 41ap (repeating units P) on which the positive active material layer 42 is disposed; and a positive lead section 41b, which is connected to the positive current collector section 41a. The plurality of repeating units 41ap and the positive lead section 41b are arranged in a row along a direction Dp orthogonal to the width direction WDp of the positive current collector 41. At the boundaries of adjacent repeating units 41ap and at the boundaries between repeating units 41ap and the positive lead section 41b, there are bends 43 extending parallel to the width direction WDp.

[0084] Multiple repeating units 41ap each have the same shape (octagonal in this example) and the same size. A positive electrode active material layer 42 is formed on one side of the positive electrode current collector 41. As shown, the positive electrode active material layer 42 can be formed to completely cover one side of the repeating unit 41ap.

[0085] In one illustrated example, the positive lead portion 41b has a first end 41ba connected to the positive current collector portion 41a and a second end 41bb connected to the first end 41ba. The first end 41ba and the second end 41bb have the same shape and size as the repeating unit 41ap. The overall length of the positive lead portion 41b in the direction Dp is 2Lp (twice the length Lp of the repeating unit 41ap). The first end 41ba and the second end 41bb are bent at the bend between them and are stacked in the laminate 30. That is, the positive lead portions 41b are overlapped in a folded manner in the laminate 30. Alternatively, the first end 41ba and the second end 41bb may each have a different shape than the repeating unit 41ap. The second end 41bb is connected to the housing 20, which serves as the positive terminal, by welding or the like.

[0086] As shown in the figure, the negative electrode plate 50 includes a negative electrode current collector 51 and a negative electrode active material layer 52 disposed on the negative electrode current collector 51. The negative electrode current collector 51 includes a negative electrode current collector section 51a, which includes a plurality of repeating units 51an (repeating units N) on the surface of which the negative electrode active material layer 52 is disposed; and a negative electrode lead section 51b, which is connected to the negative electrode current collector section 51a. The plurality of repeating units 51an and the negative electrode lead section 51b are arranged in a row along a direction Dn orthogonal to the width direction WDn of the negative electrode current collector 51. There are bends 53 extending parallel to the width direction WDn at the boundaries of adjacent repeating units 51an and at the boundaries between repeating units 51an and negative electrode lead sections 51b.

[0087] Multiple repeating units 51an each have the same shape (octagonal in this example) and the same size. A negative electrode active material layer 52 is formed on one side of the negative electrode current collector 51. As shown, the negative electrode active material layer 52 can be formed to completely cover one side of the repeating unit 51an.

[0088] In one illustrated example, the negative electrode lead portion 51b has a first end 51ba connected to the negative electrode current collector portion 51a and a second end 51bb connected to the first end 51ba. The first end 51ba and the second end 51bb have the same shape and size as the repeating unit 51an. The overall length of the negative electrode lead portion 51b in the direction Dn is 2Ln (twice the length Ln of the repeating unit 51an). The first end 51ba and the second end 51bb are bent at the bend between them and are stacked in the laminate 30. That is, the negative electrode lead portions 51b are overlapped in a folded manner in the laminate 30. Alternatively, the first end 51ba and the second end 51bb may each have a different shape than the repeating unit 51an. The second end 51bb is connected to the sealing plate 22, which serves as the negative electrode, by welding or the like.

[0089] The sealing plate 22 shown in the figure has a circular plate-shaped portion and a cylindrical sidewall portion that rises from the outer edge of the circular plate-shaped portion. That is, the sealing plate 22 in this example has a container-like shape. When the sealing plate 22 is the negative terminal, there is an end 60n on the circular plate-shaped portion side of the sealing plate 22 and an end 60p on the opening side of the sealing plate 22. When electrolyte is injected with the circular plate-shaped portion of the sealing plate 22 as the lower side, the presence of the end 60p makes the injection of electrolyte easier. That is, from the viewpoint of making electrolyte injection easier, it is particularly preferable that the separator 60 has an end 60p stacked on the positive electrode lead portion 41b connected to the housing body 21.

[0090] like Figure 3AAs shown, the bending portions 43 of repeating unit 41ap, 53 of repeating unit 51an, and 63 of repeating unit 60s are parallel to and repeating unit WDp, WDn, and WDs in the width direction (see reference). Figure 3C The positive electrode plate 40, the negative electrode plate 50, and the separator 60 are arranged in an overlapping manner. Figure 3A In the diagram, directions Dp, Dn, and Ds are directions parallel to the main surface of the positive current collector 41, the main surface of the negative current collector 51, and the main surface of the separator 60, respectively.

[0091] The separator 60 includes repeating units 60s and end portions 60p (end portion SP) and 60n (end portion SN) disposed at both ends of the repeating units 60s. The repeating units 60s, end portions 60p, and end portions 60n are arranged in a row along a direction Ds orthogonal to the width direction WDs of the separator 60. The repeating unit 60s has a width Ws and a length Ls along the direction Ds. In one illustrated example, end portions 60p and 60n have shapes formed by cutting the repeating unit 60s with lengths Lps and Lns, respectively. However, end portions 60p and 60n are not limited to the illustrated shapes. Typically, the widths of end portions 60p and 60n are the same as or shorter than the width Ws of the repeating unit 60s.

[0092] Repeating unit 41ap has a width Wp and a length Lp in the direction Dp. Repeating unit 51an has a width Wn and a length Ln in the direction Dn. The lengths Lp and Ln are usually the same, but can be slightly different. For example, the length Lp can be in the range of 0.9 to 1.1 times (0.95 to 1.05 times) the length Ln. The width Wp is the same as or slightly different from the width Wn. For example, the width Wp can be in the range of 0.8 to 1.2 times (e.g., 0.8 to 1.0 times) the width Wn. The area of ​​repeating unit 41ap can be in the range of 0.8 to 1.2 times (e.g., 0.8 to 1.0 times) the area of ​​repeating unit 51an. When the lengths Lp and Ln are the same, Lp can be set to Lp = Ln = Ls. When the lengths Lp and Ln are different, the length Ls can be set to be more than the smaller of Lp and less than the larger of Ls.

[0093] The repeating unit 60s of the separator 60 has a planar shape that prevents contact between the positive electrode active material layer 42 and the negative electrode active material layer 52 sandwiched between the separator 60. For example, in one illustrated example, the repeating unit 60s has a shape formed by stretching the octagon of the repeating unit 41ap in the width direction WDs. In one illustrated example, Wp < Ws, Wn < Ws. The battery (B) of the present invention can also satisfy Wp < Wn < Ws.

[0094] like Figure 2 As shown, end 60p is the end that bends at the boundary between the positive current collector 41a and the positive lead 41b and is stacked with the positive lead 41b. Similarly, end 60n is the end that bends at the boundary between the negative current collector 51a and the negative lead 51b and is stacked with the negative lead 51b. The length Lps of end 60p in the direction Ds is in the range of 0.3 to 0.7 times the length Ls. The length Lns of end 60n in the direction Ds is in the range of 0.3 to 0.7 times the length Ls. By using ends 60p and 60n, the bend at the boundary between the current collector and the lead is covered. Therefore, short circuits between the positive plate 40 and the negative plate 50 can be prevented.

[0095] exist Figure 4 The diagram schematically illustrates the stacked body 30 as viewed from the stacking direction. In this diagram, Figure 4 The diagram shows the state after the second end 51bb has been unfolded. (Refer to...) Figures 3A-4 It can be seen that the end portion 60n extends outward in the width direction WDs compared to the repeating unit 51an and the negative electrode lead portion 51b. Similarly, the end portion 60p extends outward in the width direction WDs compared to the repeating unit 41ap and the positive electrode lead portion 41b. According to this structure, the electrolyte can easily penetrate into the laminate through the portions that protrude from the repeating units and the lead portions.

[0096] The battery (B) of the present invention may also include two insulating strips that respectively cover at least a portion of two sides of the laminate where bends exist. Figure 5A as well as Figure 5B The image schematically illustrates an example of a laminated structure using insulating tape. Figure 5A This is a top view showing the state after the second end 51bb is unfolded. Figure 5B This schematically shows a side view of the laminate 30 with the bent portions of its constituent members slightly extended and the constituent members separated. Additionally, in Figure 5B The middle lead is indicated by a dashed line. Additionally, in Figure 5B The illustration of the active substance is omitted.

[0097] Reference Figure 5BThe positive current collector 41 (positive plate 40) is bent at the bend 43. The negative current collector 51 (negative plate 50) is bent at the bend 53. The separator 60 is bent at the bend 63. An insulating tape 71 covers the two sides of the laminate 30 where the bends are located. The width of the insulating tape 71 is longer than the length (length in the width direction) of the bends 43 and 53, and shorter than the widths Wp and Wn. By using the insulating tape 71, short circuits between the positive current collector 41 exposed at the bend 43 of the positive plate 40 and the sealing plate 22, and between the negative current collector 51 exposed at the bend 53 of the negative plate 50 and the housing body 21, can be prevented. In addition, by using the insulating tape 71, the operation of the laminate 30 is made easier, thus simplifying manufacturing. The ends 60p and 60n of the separator 60 extend outwards from the insulating tape 71 in the width direction WDs. That is, the ends 60p and 60n include portions not covered by the insulating tape 71. According to this structure, liquid injection becomes easier.

[0098] Example

[0099] The invention will be further described in detail with reference to the embodiments. In this embodiment, a product having the same characteristics as... Figure 1 A non-aqueous electrolyte secondary battery with the same structure as battery 10 shown was evaluated. The number of repeating cells was set to 13, and [the following was used]. Figure 5A as well as Figure 5B The insulating tape 71 is shown. In this embodiment, various secondary batteries with different lengths of the ends 60p and 60n of the separator 60 were fabricated. The fabrication method and evaluation method of these secondary batteries are described below.

[0100] (Battery A1)

[0101] Battery A1 is manufactured using the following method. First, prepare a positive plate 40, a negative plate 50, and a separator 60. Set the number of each repeating unit to 13.

[0102] The planar shape of the repeating unit 41ap of the positive current collector 41 is set to an approximately regular octagon with Lp = Wp = 6.0 mm. The positive current collector 41 uses a first end 41ba and a second end 41bb (refer to) comprising 13 repeating units 41ap, having the same planar shape and the same dimensions as the repeating units 41ap. Figure 3C The current collector includes aluminum foil.

[0103] The planar shape of the repeating unit 51an of the negative current collector 51 is set to an approximately octagon with Ln = 6.0 mm and Wn = 7.0 mm. The negative current collector 51 uses a first end 51ba and a second end 51bb (refer to) comprising 13 repeating units 51an, having the same planar shape and the same dimensions as the repeating units 51an. Figure 3C The current collectors include the positive current collector 41 and the negative current collector 51. The outer edges of the positive current collector 41 near the bend and the outer edges of the negative current collector 51 are rounded in a curved manner.

[0104] The planar shape of the repeating unit 60s of the separator 60 is set to an octagon with Ls = 6.0 mm and Ws = 8.0 mm. The separator 60 uses a microporous membrane made of polyethylene (14 μm thick). The separator 60 uses a structure with ends 60p and 60n. The lengths Lps of the ends 60p and Lns of the ends 60n of the separator 60 are set to the lengths expressed in Table 1.

[0105] A positive electrode plate is obtained by coating a positive electrode agent onto a repeating unit 41ap on one side of the positive electrode current collector 41 to form a positive electrode active material layer with a thickness of 55 μm. A positive electrode agent constituting the positive electrode active material layer is prepared by mixing lithium cobalt oxide (LiCoO2) as the positive electrode active material, acetylene black as the conductive agent, and polyvinylidene fluoride as the binder in a mass ratio of lithium cobalt oxide:acetylene black:polyvinylidene fluoride = 9:0.1:0.1. A negative electrode plate is obtained by coating a negative electrode agent onto a repeating unit 51an on one side of the negative electrode current collector to form a negative electrode active material layer with a thickness of 60 μm. A negative electrode plate is prepared by mixing graphite as the negative electrode active material, carboxymethyl cellulose (CMC) as the thickener, and styrene-butadiene rubber (SBR) as the binder in a mass ratio of graphite:CMC:SBR = 9:0.1:0.1. A negative electrode agent constituting the negative electrode active material layer is prepared by mixing graphite as the negative electrode active material, carboxymethyl cellulose (CMC) as the thickener, and styrene-butadiene rubber (SBR) as the binder in a mass ratio of graphite:CMC:SBR = 9:0.1:0.1.

[0106] The above-mentioned positive electrode plate, negative electrode plate and separator are as follows: Figure 3A The plates are overlapped as shown. Then, the separator and negative electrode plate are fixed by welding. Next, the positive electrode plate, negative electrode plate, and separator are bent at their respective bends to form a laminate. The two sides of the laminate containing the bends are covered with two insulating strips (5mm wide). The insulating strips are as follows... Figure 5A as well as Figure 5B Paste it onto the stack as shown.

[0107] Next, the second end 41bb of the positive current collector 41 is welded to the coin-shaped housing body. Additionally, the second end 51bb of the negative current collector 51 is welded to a sealing plate with a gasket. Next, a laminate is placed inside the sealing plate with the gasket, and then a non-aqueous electrolyte is injected. The non-aqueous electrolyte is injected with the circular portion of the sealing plate facing downwards. The non-aqueous electrolyte is prepared by dissolving LiPF6 in a non-aqueous solvent. The non-aqueous solvent is prepared by mixing ethylene carbonate, propylene carbonate, and methyl ethyl carbonate in a volume ratio of ethylene carbonate:propylene carbonate:methyl ethyl carbonate = 30:1:61.

[0108] Next, the casing body is covered by a sealing plate with a gasket, deforming and sealing the open end of the casing body. This yields battery A1. Furthermore, the casing, gasket, and sealing plate are all components designed to produce a battery with an outer diameter of 9.5 mm and a height of 2.0 mm.

[0109] The following evaluation was made regarding the manufacturing process of battery A1 and the manufactured battery A1.

[0110] (Homework Time)

[0111] When manufacturing 10 batteries A1, the time taken for each battery from the start of electrolyte injection to the sealing of the casing by covering it with a sealing plate after the electrolyte injection was completed was measured. The arithmetic mean of these times was then calculated. A shorter processing time indicates more efficient manufacturing.

[0112] (Evaluation of the yield rate of laminated structures)

[0113] Ten stacked plates (plate assemblies) of battery A1 were fabricated. Then, the presence of short circuits between the positive and negative plates of the fabricated stacks was checked. The percentage of stacks without short circuits was then calculated (yield (%)). A higher yield indicates a better manufacturing process.

[0114] (Evaluation of battery height)

[0115] Ten batteries A1 were fabricated, and their heights were measured. The arithmetic mean of the measured heights was then calculated. The smaller the difference between the calculated average height and 2.0 mm (the design value), the better.

[0116] (Evaluation of internal resistance)

[0117] Ten batteries A1 were fabricated, and the internal resistance of each battery A1 was measured. Then, the arithmetic mean of the measured internal resistances was calculated. From the perspective of battery characteristics, lower internal resistance is preferable.

[0118] (Evaluation of charge-discharge cycle count)

[0119] Charge-discharge cycle tests were conducted on 10 batteries A1, and the number of charge-discharge cycles was recorded when the discharge capacity decreased to 80% of the initial discharge capacity. Then, the arithmetic mean of the recorded charge-discharge cycle counts was calculated to determine the charge-discharge cycle count X. A higher X count indicates better battery characteristics. The charge-discharge cycle test was conducted by repeatedly performing a charge cycle consisting of charging at 6mA to 4.35V and discharging at 6mA to 3.0V, which was defined as one cycle.

[0120] (Other batteries)

[0121] The lengths Lps of end 60p and Lns of end 60n of separator 60 were varied relative to Ls in the manner shown in Table 1. Otherwise, the battery shown in Table 1 was manufactured under the same conditions as battery A1. Furthermore, except for battery C1, separator 60 used separators with ends 60p and 60n. The separator used in battery C1 in Table 1 is a separator excluding ends 60p and 60n. The manufactured battery underwent the same evaluation as battery A1.

[0122] The proportions of the lengths of the ends of the separators used in the manufactured batteries and the evaluation results are shown in Table 1. Batteries C1 to C4 are comparative example batteries, and batteries A1 to A3 are batteries of the present invention.

[0123] [Table 1]

[0124]

[0125] Batteries A1 to A3, with lengths Lps and Lns ranging from 0.3Ls to 0.7Ls respectively, can be manufactured with a shorter processing time and a high yield. Furthermore, batteries A1 to A3 have a higher number of charge-discharge cycles X. Moreover, in batteries A1 to A3, the battery height is almost identical to the design value, and the internal resistance is low.

[0126] For the manufacture of batteries C1 and C2 with lengths Lps and Lns of 0.2 or less, the processing time is long and the yield is low. Furthermore, the number of charge-discharge cycles X for batteries C1 and C2 is relatively low. The long processing time is due to the short ends of the separators, resulting in slow electrolyte penetration and requiring multiple electrolyte injections. The low yield and low number of charge-discharge cycles X are attributed to the tendency for short circuits to occur at the junction (bend) between the current collector and the lead section.

[0127] Manufacturing batteries C3 and C4, with lengths Lps and Lns of 0.8 or more, results in longer manufacturing times. Additionally, the battery height is significantly higher than designed. Furthermore, batteries C3 and C4 have fewer charge-discharge cycle counts (X). The longer manufacturing time is due to the fact that if the separator end is long, it easily overlaps the gasket mounted on the sealing plate during casing installation, requiring the separator to be pressed into the sealing plate. Furthermore, a longer separator end increases the battery height after sealing due to its larger volume and the presence of separator residue on the gasket. The lower charge-discharge cycle count (X) for batteries C3 and C4 is due to sealing with the separator inserted between the casing body and the gasket. Sealing in this state causes electrolyte to be squeezed out of the battery, resulting in less electrolyte contributing to internal reactions.

[0128] As described above, the battery of the present invention can be manufactured with good yield and efficiency without compromising characteristics. Furthermore, while the above embodiment uses a separator including both end 60p and end 60n, the same effect can be achieved using a separator including only one end.

[0129] Industrial availability

[0130] This invention can be applied to coin-shaped batteries.

[0131] Explanation of reference numerals in the attached figures

[0132] 10. Battery (coin-shaped battery); 30. Laminated structure; 40. Positive electrode plate; 41. Positive current collector; 41a. Positive current collector section; 41ap, 51an, 60s. Repeating unit (repeating unit P, N, S); 41b. Positive lead section; 42. Positive active material layer; 43, 53, 63. Bending section; 50. Negative electrode plate; 51. Negative current collector; 51a. Negative current collector section; 51b. Negative lead section; 52. Negative active material layer; 60. Separator; 60p, 60n. End (end SP, SN); 71. Insulating strip; Dn, Dp, Ds. Direction; Ls, Lns, Lnp, Lp, Ln. Length; WDp, WDn, WDs. Width direction.

Claims

1. A coin-shaped battery, wherein, The coin-shaped battery comprises a stack of positive plates, negative plates, and separators bent in a zigzag shape, with the separators positioned between the positive and negative plates. The positive electrode plate includes: a positive current collector, comprising a positive current collector portion and a positive lead portion connected to the positive current collector portion, the positive current collector portion comprising a plurality of repeating units P arranged in a row; and a positive active material layer disposed on the plurality of repeating units P. The negative electrode plate includes: a negative current collector, which includes a negative current collector portion and a negative lead portion connected to the negative current collector portion, the negative current collector portion including a plurality of repeating units N arranged in a row; and a negative active material layer disposed on the plurality of repeating units N. The separator comprises a plurality of repeating units S arranged in a column along a direction (Ds) orthogonal to its width direction (WDs). In the laminated structure, the positive current collector, the negative current collector, and the separator are bent at their respective bending portions in a manner that stacks the plurality of repeating units P, the plurality of repeating units N, the plurality of repeating units S, the positive lead portion, and the negative lead portion. The separator includes at least one end selected from the group consisting of an end SP and an end SN, wherein the end SP is bent together with the positive current collector at the boundary between the positive current collector and the positive lead and is stacked with a portion of the positive lead, and the end SN is bent together with the negative current collector at the boundary between the negative current collector and the negative lead and is stacked with a portion of the negative lead. When the length of the repeating unit S in the direction (Ds) is set to Ls, the lengths of the end SP and the end SN in the direction (Ds) are respectively in the range of 0.3Ls to 0.7Ls.

2. The coin-shaped battery according to claim 1, wherein, The coin-shaped battery also includes two insulating strips that cover at least a portion of the two sides of the laminate where the bend exists. The at least one end of the separator includes a portion not covered by the insulating tape.

3. The coin-shaped battery according to claim 1, wherein, The end portion SP extends outward in the width direction (WDs) compared to the repeating unit P, and the end portion SN extends outward in the width direction (WDs) compared to the repeating unit N.

4. The coin-shaped battery according to claim 1, wherein, The positive electrode lead portion and the negative electrode lead portion are respectively overlapped in the laminate in a folded manner.

5. The coin-shaped battery according to claim 1, wherein, The at least one end of the separator is fixed to at least one lead portion selected from the group consisting of the positive lead portion and the negative lead portion.

6. The coin-shaped battery according to claim 1, wherein, This coin-shaped battery is a rechargeable battery.

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