Battery and method for manufacturing battery

Abstract

A battery according to one embodiment of the present invention is provided with: an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween; an outer can (16) that houses the electrode body and has an opening at one end; and a sealing body that closes the opening of the outer can (16). The outer can (16) has an identification display (36) formed on the inner surface.

Description

Technical Field

[0001] The present invention relates to a battery and a method for manufacturing the battery. Background Art

[0002] Batteries equipped with identification displays are known (see, for example, Patent Documents 1 and 2). This identification display can be used to identify the battery's production line, manufacturing date, and time. For example, if a battery experiences a problem during the manufacturing process or after shipment, this identification display can be used to analyze the cause.

[0003] Patent Document 1 describes providing a two-dimensional code (identification display) representing identification information on the outer circumference of a battery case (outer can) at a predetermined distance from the bottom. Patent Document 2 describes providing an identification barcode (identification display) on the outer circumference or end face of a battery can (outer can).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-210663

[0007] Patent Document 2: Japanese Patent Application No. 2015-524142 Summary of the Invention

[0008] When an identification display is provided on the outer peripheral surface of the battery's outer can, as in the configurations described in Patent Documents 1 and 2, during the manufacturing process of a battery module containing multiple batteries and battery holders, the identification display may be damaged due to contact between other components such as the battery holder and the outer peripheral surface of the battery. This may make it difficult to read the identification display. In addition, when an identification display is provided on the end face or outer peripheral surface of the battery's outer can, abnormal heating of other batteries surrounding the battery with the identification display in the battery module may cause thermal effects on the outer surface of the outer can of the battery with the identification display, causing discoloration or deformation of the identification display, making it difficult to read the display.

[0009] The battery of the present invention is a battery comprising an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween, an outer can housing the electrode body and having an opening at one end, and a sealing member for sealing the opening of the outer can, wherein the outer can has an identification display formed on its inner surface.

[0010] The battery manufacturing method of the present invention is a method for manufacturing a battery comprising an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator therebetween, an outer packaging can that houses the electrode body and has an opening at one end, and a sealing body that seals the opening of the outer packaging can, wherein the outer packaging can has an identification display formed on the inner surface. In this manufacturing method, a laser is irradiated from the outside of the outer packaging can toward the inner surface of the outer packaging can to form the identification display.

[0011] According to the present invention, a battery and its manufacturing method provide an identification display on the inner surface of the outer can, a location that prevents contact with other components during the manufacturing process of the battery module containing the battery and is less susceptible to abnormal heating of other surrounding batteries. This facilitates reading the identification display both after the battery is assembled into a battery module and after abnormal heating of other batteries in the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a diagram schematically showing an axial cross section of a cylindrical battery as an example of an embodiment.

[0013] Figure 2 It is observed from above Figure 1 A diagram of the inner surface of the bottom of the outer packaging can of a cylindrical battery.

[0014] Figure 3 This is a schematic cross-sectional view of the outer packaging can when an identification display is provided on the inner surface of the bottom of the outer packaging can in an embodiment.

[0015] Figure 4 In another embodiment of the cylindrical battery Figure 3 The corresponding figure. DETAILED DESCRIPTION

[0016] Below, an embodiment of the sealed battery of the present invention is described in detail with reference to the accompanying drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. In addition, the present invention also includes forms in which the components of the embodiments described below are selectively combined.

[0017] The following illustrates a cylindrical battery 10 having a wound electrode assembly 14 housed in a bottomed cylindrical outer can 16. However, the outer can is not limited to a cylindrical outer can. The battery of the present invention may also be a prismatic battery having a prismatic outer can, for example. It should be noted that while the cylindrical battery 10 of this embodiment is a secondary battery, the battery of the present invention may also be a primary battery.

[0018] Figure 1Schematically shows an axial cross section of a cylindrical battery 10 as an example of an embodiment. Figure 1 As shown, the cylindrical battery 10 includes an electrode body 14, an electrolyte, and an outer can 16 for storing the electrode body 14 and the electrolyte. The electrode body 14 includes a positive electrode plate 11, a negative electrode plate 12, and a separator 13, and has a structure in which the positive electrode plate 11 and the negative electrode plate 12 are spirally wound with the separator 13 interposed therebetween. The outer can 16 is a metal container with a bottomed cylindrical shape, having a substantially cylindrical barrel 16a open on one axial side and a bottom 16b at the other axial end of the barrel 16a. The opening of the barrel 16a is sealed by a sealing body 17. For the sake of convenience in the following description, the sealing body 17 side of the cylindrical battery 10 is set as the top, and the bottom 16b side of the outer can 16 is set as the bottom.

[0019] The electrolyte may be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixed solvents of two or more thereof. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixed solvents thereof. The non-aqueous solvent may contain a halogen-substituted substance (e.g., fluoroethylene carbonate) in which at least a portion of the hydrogen atoms of these solvents are replaced with halogen atoms such as fluorine. Examples of electrolyte salts include lithium salts such as LiPF6.

[0020] The positive electrode plate 11, negative electrode plate 12, and separator 13 that make up the electrode assembly 14 are all long, ribbon-like strips, wound in a spiral and stacked radially along the electrode assembly 14. To prevent lithium precipitation, the negative electrode plate 12 is slightly larger than the positive electrode plate 11. In other words, the negative electrode plate 12 is longer in both the length and width (short-side direction) than the positive electrode plate 11. The separator 13 is at least slightly larger than the positive electrode plate 11, and two separators are positioned to sandwich the positive electrode plate 11.

[0021] The positive electrode plate 11 includes a positive electrode core 30 and a positive electrode mixture layer 31 formed on the positive electrode core 30. The positive electrode core 30 can be made of a metal foil such as aluminum or an aluminum alloy that is stable within the potential range of the positive electrode plate 11, or a film having the metal disposed on the surface. The positive electrode mixture layer 31 contains a positive electrode active material, a conductive agent such as carbon black or carbon nanotubes, and a binder such as polyvinylidene fluoride. The positive electrode mixture layer 31 is preferably formed on both sides of the positive electrode core 30. A positive electrode mixture slurry containing a positive electrode active material, a conductive agent, and a binder is applied to both sides of the positive electrode core 30 and the coating is compressed to produce the positive electrode plate 11.

[0022] An example of the positive electrode active material contained in the positive electrode mixture layer 31 is a lithium transition metal composite oxide. A lithium transition metal composite oxide is a composite oxide containing metal elements such as Co, Mn, Ni, and Al in addition to Li. The metal elements constituting this composite oxide are, for example, at least one selected from the group consisting of Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi. Among these, at least one selected from the group consisting of Ni, Mn, and Co is preferably contained.

[0023] The negative electrode plate 12 includes a negative electrode core 40 and a negative electrode mixture layer 41 formed on the negative electrode core 40. The negative electrode core 40 can be made of a metal foil such as copper or a copper alloy that is stable within the potential range of the negative electrode plate 12, or a film having the metal disposed on the surface. The negative electrode mixture layer 41 contains a negative electrode active material, a binder, and, if necessary, a conductive agent such as carbon black or carbon nanotubes. The negative electrode mixture layer 41 is preferably formed on both sides of the negative electrode core 40. For example, styrene-butadiene rubber (SBR) can be used as the binder, and carboxymethyl cellulose or its salt can also be used in combination. The negative electrode mixture slurry containing the negative electrode active material and the binder is applied to both sides of the negative electrode core 40 and the coating is compressed to produce the negative electrode plate 12.

[0024] An example of the negative electrode active material contained in the negative electrode mixture layer 41 is a carbon material such as graphite that reversibly occludes and releases lithium ions. The graphite can be either natural graphite or artificial graphite. As the negative electrode active material, elements such as Si and Sn that alloy with Li, materials containing such elements, etc. can be used. Among them, composite materials containing Si are preferred. As a suitable example of a composite material containing Si, a material in which a fine Si phase is dispersed in a SiO2 phase, a silicate phase such as lithium silicate, a carbon phase, or a silicide phase can be cited.

[0025] The separator 13 uses a porous sheet with ion permeability and insulation. Specific examples of the porous sheet include microporous films, woven fabrics, non-woven fabrics, and the like. Suitable materials for the separator 13 include polyolefins such as polyethylene and polypropylene, and cellulose. The separator 13 may be a single-layer structure or a multi-layer structure. In addition, a resin layer with high heat resistance such as an aromatic polyamide resin may be formed on the surface of the separator 13. A filler layer containing an inorganic filler may be formed at the interface between the separator 13 and at least one of the positive electrode plate 11 and the negative electrode plate 12.

[0026] Insulating plates 18 and 19 are disposed above and below the electrode body 14 , respectively. Figure 1In the example shown, the positive electrode lead 20 extends through a through-hole in the insulating plate 18 toward the sealing body 17, while the negative electrode lead 21 extends through the outside of the insulating plate 19 toward the bottom 16b of the outer can 16. The positive electrode lead 20 is connected to the lower surface of an internal terminal plate 23 of the sealing body 17 by laser welding or other means. The cap 27, which serves as the top plate of the sealing body 17 and is electrically connected to the internal terminal plate 23, serves as the positive electrode terminal. The negative electrode lead 21 is connected to the inner surface of the bottom 16b of the outer can 16 by laser welding or other means, with the outer can 16 serving as the negative electrode terminal.

[0027] The positive electrode lead 20 is bonded to the positive electrode core 30 by ultrasonic welding or the like. For example, the positive electrode lead 20 is bonded to the longitudinal center of the positive electrode plate 11, spaced from both longitudinal ends. The positive electrode lead 20 can be bonded to positions substantially equidistant from both longitudinal ends of the positive electrode plate 11. The negative electrode lead 21 is bonded to the negative electrode core 40 by ultrasonic welding or the like. Figure 1 In the example shown, a negative electrode lead 21 is joined to the winding end of the negative electrode plate 12, which is located on the outer periphery of the electrode body 14. The positive and negative electrode leads 20 and 21 are, for example, strip-shaped metal members having a thickness of 30 to 100 μm.

[0028] The negative electrode plate 12 may be disposed on the outer circumference of the electrode body 14. Alternatively, an exposed portion may be formed on the outer circumference of the electrode body 14, exposing the surface of the negative electrode core 40. This exposed portion may also be in contact with the inner surface of the outer can 16, electrically connecting the negative electrode plate 12 to the outer can 16. In this case, the negative electrode plate 12 may not have the negative electrode lead 21.

[0029] As described above, the outer can 16 is a metal container with a bottom and a cylindrical shape that is open on one side in the axial direction. A gasket 28 is provided between the outer can 16 and the sealing body 17 to ensure the airtightness of the battery interior and the insulation between the outer can 16 and the sealing body 17. A groove 22 is formed in the upper portion of the outer can 16, in which a portion of the cylindrical portion 16a bulges inward to support the sealing body 17. The groove 22 is preferably formed in an annular shape along the circumferential direction of the outer can 16, and its upper surface supports the sealing body 17. The sealing body 17 is fixed to the upper portion of the outer can 16 by the groove 22 and the open end of the outer can 16 that is crimped to the sealing body 17.

[0030] The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26 and a cap 27 are stacked in order from the electrode body 14 side. The various components constituting the sealing body 17 have, for example, a disc shape or a ring shape, and the various components except the insulating member 25 are electrically connected to each other. The lower valve body 24 and the upper valve body 26 are connected at their respective central portions, and an insulating member 25 is sandwiched between their respective peripheral portions. When an abnormality occurs in the battery and the internal pressure rises, the lower valve body 24 is deformed and broken in a manner that pushes the upper valve body 26 toward the cap 27 side, thereby blocking the current path between the lower valve body 24 and the upper valve body 26. When the internal pressure rises further, the upper valve body 26 breaks and gas is discharged from the opening of the cap 27.

[0031] Figure 2 This is a diagram showing the inner surface of the bottom 16b of the outer can 16 of the cylindrical battery 10 as viewed from above. Figure 2 As shown, the outer can 16 has an identification mark 36 formed on the inner surface of the disk-shaped bottom 16b. To avoid contact between the inner surface of the bottom 16b and the negative electrode lead 21, the identification mark 36 is formed away from the center of the inner surface of the bottom 16b.

[0032] The identification display 36 is an independent display attached to the cylindrical battery 10, providing identification information for distinguishing it from other cylindrical batteries 10. A different identification display 36 is provided for each cylindrical battery 10, or for each group of a predetermined number of cylindrical batteries 10. The identification display 36 may be a batch number attached to a group of products manufactured at the same time, or a product number attached to each individual product.

[0033] The identification display 36 allows individual cylindrical batteries 10 or individual manufacturing batches to be distinguished and is used to obtain information about the manufacturing of the cylindrical batteries 10. For example, the manufacturer of the cylindrical batteries 10 may have a database containing information about the manufacturing of the cylindrical batteries 10, which is associated with the identification display 36 of the cylindrical batteries 10. Therefore, by reading the identification display 36 using a reader or other device and identifying the cylindrical battery 10, information about the manufacturing of the cylindrical battery 10 can be obtained. An example of information about the manufacturing of the cylindrical batteries 10 is a history of the manufacturing process including information such as the production line and the date and time of manufacturing.

[0034] The identification display 36 includes, for example, at least one selected from the group consisting of numbers, characters, and identification codes. The identification display 36 may be a combination of numbers and characters. The identification code constituting the identification display 36 may be a one-dimensional code, a two-dimensional code, or a three-dimensional code, but is preferably a two-dimensional code. Figure 2 In the example shown, a square two-dimensional code (QR code (registered trademark)) is formed as the identification display 36 .

[0035] The identification mark 36 can be formed by at least one selected from a protrusion and a depression, as long as it can be read by a reader or other reading device. Alternatively, the identification mark 36 may have a color different from the surrounding area. The numbers, characters, or identification code forming the identification mark 36 may not have protrusions or depressions, but may simply have a color different from the surrounding area.

[0036] The identification display 36 can be formed by pressing, etc., but is preferably formed by laser marking. Laser marking is a method of forming a display by irradiating a laser beam onto a portion where the display is to be formed. When the identification display 36 is a laser marking display, for example, the display is formed by discoloration of the portion irradiated with the laser beam. Alternatively, a depression may be formed in the portion irradiated with the laser beam. Because the laser marking display has excellent durability, poor reading is less likely to occur even after the cylindrical battery 10 has been used.

[0037] Figure 3 1 is a schematic cross-sectional view of the outer packaging can 16 when the identification display 36 is provided on the inner surface of the bottom 16b of the outer packaging can 16 in the embodiment. Figure 3 As shown, in the manufacturing method of the battery of the embodiment, when the identification mark is formed on the inner surface of the bottom 16b, the interior of the outer can 16 is set to be empty, and the cylindrical portion 16a of the outer can 16 is extended to the state before the front end is deformed by caulking, and a laser irradiation device (not shown) arranged on the upper side of the outer side of the outer can 16 is directed toward the inner surface of the bottom 16b in the vertical direction downward ( Figure 3 Thus, the identification display 36 ( Figure 2 ).

[0038] When the identification display 36 is formed by irradiating the inner surface of the bottom 16b with a laser, it is possible to prevent the identification display 36 from being blurred or deformed due to the influence of the electrolyte. This can improve the reading accuracy of the identification display 36. In addition, even though the identification display 36 is formed on the inner surface of the bottom 16b at a deep position in the narrow outer packaging can 16, the identification display 36 can be formed with high precision and easily by irradiation with laser. In addition, when the identification display 36 is formed on the inner surface of the bottom 16b, it is easy to make the portion where the identification display 36 is formed into a flat surface that is roughly orthogonal to the irradiation direction of the laser. From this aspect, the identification display 36 can also be formed with high precision.

[0039] According to the cylindrical battery 10 and its manufacturing method described above, an identification indicator 36 is provided on the inner surface of the outer can 16, a location that prevents contact with other components during the manufacturing process of the battery module containing the cylindrical battery 10 and is less susceptible to the effects of abnormal heating of other surrounding cylindrical batteries. Compared to the outer surface of the outer can 16, the inner surface of the outer can 16 is less susceptible to the heat of other surrounding cylindrical batteries. This facilitates reading of the identification indicator 36 both after the cylindrical batteries 10 are assembled into a battery module and after abnormal heating of other cylindrical batteries in the battery module.

[0040] Figure 4 In another embodiment of the cylindrical battery Figure 3 In the configuration of this example, the identification display 37 is provided on the inner surface of the cylindrical portion 16 a of the outer can 16 . Figure 4 In FIG. 1 , the range indicated by the arrow β represents the formation range of the identification display 37 in the cylindrical portion 16a. Figure 4 As shown, the identification display 37 is preferably provided on the upper portion of the inner surface of the cylinder 16a. The identification display 37 is formed, for example, by laser marking. Figure 4 As shown, in the manufacturing method of the battery of the embodiment, when the identification mark is formed on the inner surface of the cylindrical portion 16a, the interior of the outer can 16 is set to be empty, and the cylindrical portion 16a of the outer can 16 is extended to the state before being deformed by caulking the front end in a cylindrical shape, a laser irradiation device (not shown) arranged on the upper side of the outer can 16 is directed toward the inner surface of the cylindrical portion 16a in the oblique downward direction relative to the vertical direction ( Figure 4 As a result, an identification display 37 is formed on the inner surface of the cylinder 16a.

[0041] In this example, Figures 1 to 3 Similarly, the identification display 37 is provided on the inner surface of the outer can 16. Thus, in both cases after the cylindrical batteries are assembled into a battery module and after abnormal heating of other cylindrical batteries in the battery module, it is possible to easily read the identification display 37. Figures 1 to 3 The composition is the same.

[0042] Description of Reference Numerals

[0043] 10 Cylindrical battery, 11 Positive plate, 12 Negative plate, 13 Separator, 14 Electrode body, 16 Outer can, 16a Barrel, 16b Bottom, 17 Sealing body, 18, 19 Insulating plate, 20 Positive lead, 21 Negative lead, 22 Slotted portion, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating member, 26 Upper valve body, 27 Cap, 28 Gasket, 30 Positive electrode core, 31 Positive electrode mixture layer, 36, 37 Identification display.

Claims

1. A battery comprising: The positive electrode plate and the negative electrode plate are stacked with a separator between them. an outer packaging can containing the electrode body and having an opening at one end, and a sealing body for sealing the opening of the outer packaging can, The outer packaging can has an identification display formed on an inner surface.

2. The battery according to claim 1, wherein The identification display is formed on the inner surface of the bottom of the outer packaging can.

3. A method for manufacturing a battery, The battery comprises an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween, an outer can housing the electrode body and having an opening at one end, and a sealing member for sealing the opening of the outer can, wherein the outer can has an identification display formed on its inner surface. In the manufacturing method, the identification display is formed by irradiating the inner surface of the outer can with laser light from the outer side of the outer can.

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