JP5687443B2 - battery - Google Patents

Description

  The present invention relates to a battery having a wound electrode body.

  In recent years, a battery having a wound electrode body obtained by winding a positive electrode plate, a negative electrode plate, and a separator has been proposed as a battery having a high energy density (see, for example, Patent Document 1).

JP 2001-185201 A

  Patent Document 1 discloses a lithium ion secondary battery including an electrode group (hereinafter also referred to as a wound electrode body) formed by winding a positive electrode plate, a negative electrode plate, and a separator into a cylindrical shape. Furthermore, as a wound electrode body, a separator core portion (hereinafter referred to as “separator wound”) is formed by winding only a separator around a winding start position located on the innermost side of the wound electrode body. (Refer to FIG. 3 of Patent Document 1).

  By the way, when the battery is used (charge / discharge), the wound electrode body (specifically, the positive electrode plate and the negative electrode plate) expands and contracts. However, in the battery of Patent Document 1, the wound electrode body may be deformed inward (center side) as the wound electrode body (specifically, the positive electrode plate and the negative electrode plate) expands and contracts. was there. Specifically, since the separator winding portion in which the separator is simply wound cannot function sufficiently as the shaft core (it does not have sufficient strength as the shaft core), the wound electrode body is on the inner side (center side). ) Cannot be received and the deformation to the inside (center side) of the wound electrode body may not be suppressed.

  For this reason, in the battery of Patent Document 1, in accordance with the expansion / contraction of the wound electrode body (positive electrode plate and negative electrode plate), in the wound electrode body, loosening of the positive electrode plate, the negative electrode plate, and the separator (hereinafter referred to as “winding”). , Also referred to as loose winding of the wound electrode body). As a result, the distance between the positive electrode plate and the negative electrode plate adjacent to each other with the separator interposed therebetween is non-uniform, which may cause an increase in battery internal resistance and a decrease in battery capacity. Furthermore, the expansion / contraction of the wound electrode body (the positive electrode plate and the negative electrode plate) is repeated, which may cause buckling on the inner side (center side) of the wound electrode body. As a result, the positive electrode plate, the negative electrode plate, and the separator constituting the wound electrode body may be broken, and an internal short circuit (contact between the positive electrode plate and the negative electrode plate) may occur.

  This invention is made | formed in view of this present condition, Comprising: The deformation | transformation to the inner side (center side) of a wound electrode body can be suppressed, and the winding looseness and buckling of a wound electrode body can be suppressed. An object is to provide a battery.

Positive electrode plate, negative electrode plate, and an electrode body Kai wound made by winding a separator in a cylindrical shape, the positive electrode plate, the negative electrode plate, and only the separator of the separator, most of the wound electrode assembly In a battery comprising a wound electrode body having a separator wound part formed by winding a plurality of rounds from a winding start position located inside, the separator wound part is bonded or bonded to each other in the radial direction. Thus, a battery that is solidified integrally is preferable.

  In the battery described above, the wound electrode body has a separator wound portion. Here, the separator winding portion refers to only the separator among the positive electrode plate, the negative electrode plate, and the separator, a plurality of turns (for example, 10 to 20 turns) from the winding start position located on the innermost side of the wound electrode body. It is a part formed by winding.

  However, unlike the battery of Patent Document 1, the separator winding part is solidified integrally in the battery described above. In other words, the separators constituting the separator winding part are not simply wound, but are solidified as a single body (made as one lump).

  Such a separator winding part functions as a strong shaft core. For this reason, in the battery described above, the wound electrode body is prevented from being deformed inward (center side) as the wound electrode body (specifically, the positive electrode plate and the negative electrode plate) expands and contracts. be able to. Specifically, the separator winding part solidified into a single piece can receive the force that the wound electrode body tries to deform toward the inside (center side), thereby The deformation to the inner side (center side) of the wound electrode body can be suppressed.

  For this reason, in the above-described battery, the winding electrode body (the positive electrode plate and the negative electrode plate) is loosened and wound (the positive electrode plate, the negative electrode plate and the separator are loosened) due to the expansion and contraction of the wound electrode body. Can be suppressed. Thereby, it can suppress that the distance between the positive electrode plate and negative electrode plate which adjoins across a separator becomes non-uniform | heterogenous, As a result, the raise of battery internal resistance and the fall of battery capacity can be suppressed. Furthermore, “buckling of the wound electrode body” due to repeated expansion and contraction of the wound electrode body (positive electrode plate and negative electrode plate) can also be suppressed. Thereby, the fracture | rupture of the positive electrode plate, negative electrode plate, and separator which comprise a wound electrode body can be suppressed, As a result, the internal short circuit (contact with a positive electrode plate and a negative electrode plate) accompanying the said fracture | rupture can be suppressed.

One embodiment of the present invention is the battery described above, wherein the separator winding portion is a battery that is integrally solidified by adhesion of separators adjacent in the radial direction with an adhesive .

  In the battery described above, the separator winding part is integrally hardened by an adhesive (a single lump). Specifically, the separator winding part is solidified as a single piece by bonding the separators adjacent in the radial direction in the separator winding part with an adhesive.

  The separator winding part can be made a strong shaft core by solidifying the separator winding part integrally with an adhesive. Thereby, the separator winding part can receive the force that the wound electrode body tries to deform toward the inside (center side) as the wound electrode body (positive electrode plate and negative electrode plate) expands and contracts. Thereby, the deformation | transformation to the inner side (center side) of the winding electrode body can be suppressed.

  As the adhesive, for example, an epoxy resin-based adhesive (for example, Araldite; manufactured by Ciba-Gaigi) can be used.

  In addition, the “separator winding portion solidified by an adhesive” can be formed as follows, for example. For example, first, in the winding step, a wound electrode body having a “separator winding portion” formed by winding a separator only a plurality of times from a winding start position located on the innermost side of the wound electrode body is formed.

  Specifically, for example, two separators (referred to as a first separator and a second separator) are wound around the winding shaft of the winding device a plurality of times to form a separator winding portion. Thereafter, a negative electrode plate is disposed outside the first separator, the negative electrode plate is wound along the first separator, and the second separator is wound along the wound negative electrode plate. Subsequently, the positive electrode plate is disposed outside the second separator, and the positive electrode plate is wound along the second separator. After that, the first separator, the negative electrode plate 20, the second separator, and the positive electrode plate are wound to form a cylindrical wound electrode body. Thereafter, the winding shaft of the winding device is extracted from the wound electrode body. As a result, a cylindrical wound electrode body having a “separator wound portion” formed by winding a plurality of rounds from the winding start position where only the separator is located on the innermost side of the wound electrode body is formed.

  Next, an adhesive (araldite or the like) is applied to the inner peripheral surface of the separator winding portion, so that the entire separator constituting the separator winding portion is infiltrated (impregnated). Thereafter, the infiltrated adhesive is cured to form a “separator winding part solidified by the adhesive”.

  In addition, before winding the separator in the winding step, an adhesive is previously applied to a portion constituting the separator winding portion (a portion of the separator having a winding length of the separator winding portion from one end of the separator). You may make it apply | coat and wind a separator with an adhesive agent. After the separator winding part is formed, the “separator winding part solidified integrally with the adhesive” can be formed by curing the adhesive applied to the separator.

Further, a battery of the said separator winding part, it is preferable to a battery comprising hardened one body Ri by the welding of the separator adjacent to each other in the radial direction.

  In the battery described above, the separator winding portion is integrally hardened by welding of the separator that forms the separator winding portion. Specifically, separators adjacent to each other in the radial direction are welded at the separator winding part, and the separator winding part is integrally hardened (made as one lump). In other words, by welding, separators adjacent in the radial direction are joined at the separator winding portion, and the separator winding portion is integrally hardened (made as one lump).

  The separator winding part can be made a strong shaft core by solidifying the separator winding part integrally by welding the separator. Thereby, the separator winding part can receive the force that the wound electrode body tries to deform toward the inside (center side) as the wound electrode body (positive electrode plate and negative electrode plate) expands and contracts. Thereby, the deformation | transformation to the inner side (center side) of the winding electrode body can be suppressed.

  The “separator winding part solidified by welding of the separator” can be formed as follows, for example. For example, first, as described above, in the winding step, a cylindrical shape having a “separator winding portion” formed by winding only a separator around a winding start position located on the innermost side of the wound electrode body. A wound electrode body is formed. Next, a rod-shaped heater (for example, a sheathed heater) is inserted into the cylinder of the wound electrode body (specifically, inside the separator wound part), and the separator wound part (the separator constituting the same) is melted ( Soften). Thereafter, the heater is extracted from the cylinder of the wound electrode body, and the separator winding part is cured by cooling, so that the separators constituting the separator winding part are integrated (separators adjacent in the radial direction are bonded). In this manner, the “separator winding part solidified by welding of the separator” can be formed.

1 is a side view of a battery according to Example 1 and Reference Example 1. FIG. It is a top view of the battery. It is a longitudinal cross-sectional view of the battery, and corresponds to a DD cross-sectional view of FIG. It is a cross-sectional view of the battery and corresponds to the CC cross-sectional view of FIG. It is the elements on larger scale of the cross section of the battery, and is equivalent to the B section enlarged view of FIG. It is a figure which shows the positive electrode plate concerning Example 1 and Reference Example 1. FIG. It is a figure which shows the negative electrode plate concerning Example 1 and Reference Example 1. FIG. It is a longitudinal cross-sectional view of the wound electrode body concerning Example 1 and Reference Example 1. FIG. It is a figure explaining the welding process concerning the reference example 1. FIG.

(Example 1)
The battery 1 of Example 1 is a cylindrical sealed secondary battery as shown in FIGS. 1 and 2. As shown in FIG. 3, the battery 1 includes a cylindrical wound electrode body 40 and a cylindrical battery case 60 that houses the wound electrode body 40. Among these, the wound electrode body 40 is a wound electrode body in which the positive electrode plate 10, the negative electrode plate 20, the first separator 31, and the second separator 35 are wound around the axis AX in a cylindrical shape.

  As shown in FIG. 6, the positive electrode plate 10 extends along one side 10 b in the longitudinal direction (left and right direction in FIG. 6) in which the positive electrode current collector foil 11 extends, and includes the positive electrode current collector foil 11 and the positive electrode mixture layer 12. The positive electrode active material coating part 14 and the positive electrode active material coating part 14 are adjacent to the positive electrode active material application part 14 and extend along the one side 10b in the longitudinal direction. A positive electrode active material uncoated portion 13.

  For example, an aluminum foil can be used as the positive electrode current collector foil 11. The positive electrode mixture layer 12 is made of a positive electrode active material, a binder, or the like. As the positive electrode active material, for example, lithium nickelate can be used.

  As shown in FIG. 7, the negative electrode plate 20 extends along one side 20 b in the longitudinal direction (left and right direction in FIG. 7) in which the negative electrode current collector foil 21 extends, and includes the negative electrode current collector foil 21 and the negative electrode mixture layer 22. The negative electrode active material coating part 24 and the negative electrode active material coating part 24 are adjacent to the negative electrode active material coating part 24 and extend along the one side 20b in the longitudinal direction. A negative electrode active material uncoated portion 23.

As the negative electrode current collector foil 21, for example, a copper foil can be used. The negative electrode mixture layer 22 is composed of a negative electrode active material, a binder, or the like. As the negative electrode active material, for example, natural graphite can be used.
In the first embodiment, a porous sheet made of polyethylene is used as the first separator 31 and the second separator 35.

  The battery case 60 is a cylindrical battery case, and includes a metal battery case body 61 having a bottomed cylindrical shape and a metal sealing lid 62 having a disk shape (see FIGS. 1 to 3). . As shown in FIG. 3, the sealing lid 62 is caulked at an opening 61 </ b> H of the battery case body 61 with an annular gasket 69 made of an electrically insulating resin interposed between the sealing case 62 and the battery case body 61. Thus, the battery case body 61 and the sealing lid 62 that house the wound electrode body 40 are integrated while electrically insulating the battery case body 61 and the sealing lid 62, thereby forming the battery case 60. ing.

Here, the wound electrode body 40 of the first embodiment will be described in detail.
As shown in FIG. 3, the wound electrode body 40 is a positive electrode winding that forms one end (upper end in FIG. 3) of the wound electrode body 40 in the axial direction (the direction in which the axis AX extends, the vertical direction in FIG. 3). It is located between the part 44, the negative electrode winding part 46 which makes the other end part (lower end part in FIG. 3) of the winding electrode body 40 about the axial direction X, and the positive electrode winding part 44 and the negative electrode winding part 46. And a power generation unit 42.

  The positive electrode winding part 44 is a part where only the positive electrode active material uncoated part 13 of the positive electrode plate 10 is wound. The negative electrode winding part 46 is a part where only the negative electrode active material uncoated part 23 of the negative electrode plate 20 is wound. The power generation unit 42 is a portion formed by winding the positive electrode plate 10 (the positive electrode active material coating unit 14), the negative electrode plate 20 (the negative electrode active material coating unit 24), the first separator 31, and the second separator 35. . In addition, the 1st separator 31 and the 2nd separator 35 are located between the positive electrode plate 10 and the negative electrode plate 20, and electrically insulate between both electrode plates.

  The positive electrode winding part 44 is welded to the positive electrode current collector 71 made of a metal plate at the end face 44b (see FIG. 3). Further, the positive electrode current collecting member 71 is electrically connected to the ceiling portion 62 b of the sealing lid 62 through the connection member 53 made of a strip-shaped metal thin plate. Thereby, in the battery 1 of the first embodiment, the ceiling portion 62b of the sealing lid 62 serves as a positive electrode external terminal.

  The negative electrode winding part 46 is welded to the negative electrode current collector 72 made of a metal plate at its end face 46b (see FIG. 3). Further, the negative electrode current collecting member 72 is welded to the bottom 61 b of the battery case main body 61. Thereby, in the battery 1 of the present embodiment, the bottom 61b of the battery case body 61 serves as a negative external terminal.

The wound electrode body 40 is, for example, a wound electrode body obtained by winding the positive electrode plate 10 and the negative electrode plate 20 around the axis AX, but the number of windings is omitted in FIGS. 3 to 5 and 8. (In FIGS. 3 and 8, the number of turns of the positive electrode plate 10 and the negative electrode plate 20 is omitted to four rounds).
3 is a longitudinal sectional view of the battery 1 and corresponds to the DD sectional view of FIG. 4 is a cross-sectional view of the battery 1 and corresponds to the CC cross-sectional view of FIG. FIG. 5 is a partially enlarged view of a cross section of the battery 1, and corresponds to an enlarged view of a portion B in FIG.

  Furthermore, the wound electrode body 40 of the first embodiment has a separator wound portion 30. The separator winding unit 30 is configured such that only the separator (only the first separator 31 and the second separator 35) is rotated a plurality of times (for example, 10) from the winding start position SP located on the innermost side (center side) of the wound electrode body 40. It is a part formed by winding (~ 20 laps) (see FIGS. 4 and 5). 3 to 5 and 8, the number of windings of the separator winding unit 30 is omitted.

  By the way, when the battery is used (charge / discharge), the wound electrode body (specifically, the positive electrode plate and the negative electrode plate) expands and contracts. However, as described above, in the battery of Patent Document 1, as the wound electrode body (specifically, the positive electrode plate and the negative electrode plate) expands and contracts, the wound electrode body moves toward the inner side (center side). There was a risk of deformation. Specifically, since the separator winding part (separator core part) of the battery of Patent Document 1 is a separator winding part that is simply wound around the separator, it cannot sufficiently function as an axis ( There is not enough strength for the shaft core). For this reason, in the separator winding part of patent document 1, the winding electrode body cannot receive the force which is going to deform | transform toward inner side (center side), and the inner side (center side) of the winding electrode body is not received. There is a possibility that deformation cannot be suppressed.

  For this reason, in the battery of Patent Document 1, along with the expansion / contraction of the wound electrode body (positive electrode plate and negative electrode plate), in the wound electrode body, loosening of the positive electrode plate, negative electrode plate, and separator (winding) There is a risk of loosening of the rotating electrode body). As a result, the distance between the positive electrode plate and the negative electrode plate adjacent to each other with the separator interposed therebetween is non-uniform, which may cause an increase in battery internal resistance and a decrease in battery capacity. Furthermore, the expansion / contraction of the wound electrode body (the positive electrode plate and the negative electrode plate) is repeated, which may cause buckling on the inner side (center side) of the wound electrode body. As a result, the positive electrode plate, the negative electrode plate, and the separator constituting the wound electrode body may be broken, and an internal short circuit (contact between the positive electrode plate and the negative electrode plate) may occur.

  On the other hand, in the battery 1 of Example 1, unlike the battery of Patent Document 1, the separator winding part 30 is integrally hardened by an adhesive. That is, the 1st separator 31 and the 2nd separator 35 which comprise the separator winding part 30 are not only just wound, but are solidified by the adhesive agent (it is made into one lump). Specifically, in the separator winding part 30, the first separator 31 and the second separator 35 that are adjacent in the radial direction are bonded together with an adhesive, so that the separator winding part 30 is solidified integrally (one It is considered a lump).

  By separating and solidifying the separator winding part 30 using an adhesive, the separator winding part 30 can be a strong shaft core. As a result, the separator winding part 30 causes the winding electrode body 40 to deform toward the inside (center side) as the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20) expands and contracts. As a result, deformation of the wound electrode body 40 toward the inner side (center side) can be suppressed.

  For this reason, in the battery 1 of the first embodiment, loose winding (the positive electrode plate 10 and the negative electrode plate 20) due to the expansion and contraction of the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20). , Loosening of the winding of the first separator 31 and the second separator 35) can be suppressed. Thereby, it is possible to prevent the distance between the positive electrode plate 10 and the negative electrode plate 20 adjacent to each other with the separator (the first separator 31 or the second separator 35) interposed therebetween, and as a result, the battery internal resistance increases. And a decrease in battery capacity can be suppressed.

  Furthermore, “buckling of the wound electrode body 40” due to repeated expansion and contraction of the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20) can also be suppressed. Thereby, the fracture | rupture of the positive electrode plate 10, the negative electrode plate 20, the 1st separator 31, and the 2nd separator 35 which comprises the winding electrode body 40 can be suppressed, As a result, the internal short circuit (the positive electrode plate 10 and a negative electrode accompanying the said fracture | rupture) Contact with the plate 20) can be suppressed.

  In Example 1, an epoxy resin adhesive (for example, Araldite; manufactured by Ciba-Gaigi) is used as the adhesive.

  Further, in the battery 1 of the first embodiment, since the outer side (outer periphery) of the wound electrode body 40 is surrounded by the battery case body 61 (see FIGS. 3 and 4), the wound electrode body 40 (the positive electrode plate 10). And the deformation | transformation to the outer side of the winding electrode body 40 accompanying the expansion and contraction of the negative electrode plate 20) can also be suppressed. Specifically, the battery case body 61 can receive a force that the wound electrode body 40 tends to deform outward as the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20) expands and contracts. As a result, the outward deformation of the wound electrode body 40 can be suppressed. Thereby, winding looseness and buckling of the wound electrode body 40 can be further suppressed.

Next, a method for manufacturing the battery 1 will be described below.
First, as shown in FIG. 6, a positive electrode plate 10 in which a positive electrode mixture layer 12 is formed on the surface of a strip-shaped positive electrode current collector foil 11 is prepared. The positive electrode plate 10 extends along one side 10b in the longitudinal direction (left-right direction in FIG. 6) in which the positive electrode current collector foil 11 extends, and has a positive electrode current collector foil 11 and a positive electrode mixture layer 12. 14 and the positive electrode active material coating portion 14, which is adjacent to the positive electrode active material coating portion 14 and extends along the one side 10 b in the longitudinal direction, and does not have the positive electrode mixture layer 12, and is composed only of the positive electrode current collector foil 11. Part 13.

  Further, as shown in FIG. 7, a negative electrode plate 20 in which a negative electrode mixture layer 22 is formed on the surface of a strip-shaped negative electrode current collector foil 21 is prepared. The negative electrode plate 20 extends along one side 20b in the longitudinal direction (left-right direction in FIG. 7) in which the negative electrode current collector foil 21 extends, and has a negative electrode current collector foil 21 and a negative electrode mixture layer 22. 24 and the negative electrode active material coating part 24, which extends along the one side 20 b in the longitudinal direction and does not have the negative electrode mixture layer 22, and is composed only of the negative electrode current collector foil 21. Part 23.

  Also, a strip-shaped first separator 31 and a strip-shaped second separator 35 are prepared. In Example 1, a porous sheet made of polyethylene is used as the first separator 31 and the second separator 35.

Next, in the winding step, “separator winding portion” is formed by winding only the separators (the first separator 31 and the second separator 35) around the winding start position SP located on the innermost side of the wound electrode body 40. 30 ”is formed (see FIGS. 4, 5, and 8).
Specifically, first, two separators (the first separator 31 and the second separator 35) are overlapped, and a plurality of turns (for example, 10 to 10) around a winding shaft (not shown) of the winding device. 20 turns) to form the separator winding part 30 (see FIG. 5). 4 and 5, the winding direction is represented as FW.

  Thereafter, the negative electrode plate 20 is disposed outside the first separator 31, and the negative electrode plate 20 is wound along the first separator 31. Next, the second separator 35 is wound along the wound negative electrode plate 20. Subsequently, the positive electrode plate 10 is disposed outside the second separator 35, and the positive electrode plate 10 is wound along the second separator 35. However, the positive electrode active material uncoated portion 13 of the positive electrode plate 10 and the negative electrode active material uncoated portion 23 of the negative electrode plate 20 are positioned on opposite sides in the width direction (vertical direction in FIG. 8) (in FIG. 8). The negative electrode plate 20 and the positive electrode plate 10 are arranged and wound so that the positive electrode active material uncoated portion 13 is positioned above and the negative electrode active material uncoated portion 23 is positioned below.

  After that, the first separator 31, the negative electrode plate 20, the second separator 35, and the positive electrode plate 10 are wound to form a cylindrical wound electrode body. Then, the winding axis | shaft (not shown) of a winding apparatus is extracted from a winding electrode body. Thereby, the cylinder having the “separator winding part 30” formed by winding only the separator (the first separator 31 and the second separator 35) a plurality of times from the winding start position SP located on the innermost side of the wound electrode body. A spiral wound electrode body 40 is formed (see FIG. 8).

  Next, the process proceeds to an adhesion step, and an adhesive (not shown) (for example, Araldite) is applied to the inner peripheral surface 30b of the separator winding part 30. As a result, the adhesive is infiltrated (impregnated) into the whole separator (the first separator 31 and the second separator 35) constituting the separator winding part 30. Thereafter, the infiltrated adhesive is cured to form the “separator winding portion 30 solidified integrally with the adhesive”. Specifically, in the separator winding part 30, the first separator 31 and the second separator 35 that are adjacent to each other in the radial direction (left and right direction in FIG. 8) are bonded with an adhesive, so that the separator winding part 30 is integrated. It is hardened (made into one lump).

  Thereafter, the positive electrode current collecting member 71 was welded to the positive electrode winding part 44. Specifically, the surface of the positive electrode current collecting member 71 is irradiated with a laser beam in a state where the positive electrode current collecting member 71 is abutted against the end surface 44b (the upper end surface in FIG. 3) of the positive electrode winding part 44, The wound part 44 and the positive electrode current collector 71 were laser welded. Further, the negative electrode current collecting member 72 was welded to the negative electrode winding part 46. Specifically, in the state where the negative electrode current collecting member 72 is abutted against the end face 46b (the lower end face in FIG. 3) of the negative electrode winding part 46, the surface of the negative electrode current collecting member 72 is irradiated with a laser beam, The wound portion 46 and the negative electrode current collector 72 were laser welded.

  Thereafter, the wound electrode body 40 in which the positive electrode current collecting member 71 and the negative electrode current collecting member 72 are welded is accommodated in the battery case body 61 (see FIG. 3). Next, the negative electrode current collecting member 72 is welded to the bottom 61 b of the battery case body 61. Thereby, the bottom 61b of the battery case body 61 becomes a negative external terminal. Further, one end portion of the connection member 53 is welded to the positive electrode current collecting member 71, and the other end portion of the connection member 53 is welded to the ceiling portion 62 b of the sealing lid 62. Thereby, since the positive electrode current collecting member 71 and the ceiling portion 62b of the sealing lid 62 are electrically connected through the connecting member 53, the ceiling portion 62b of the sealing lid 62 serves as a positive electrode external terminal.

  Next, after injecting the electrolyte into the battery case main body 61, the battery case main body is disposed in a state where the sealing lid 62 in which the gasket 69 is disposed at the outer peripheral end 62 c is disposed inside the opening 61 </ b> H of the battery case main body 61. The opening 61H of 61 is crimped. In this manner, the battery case 60 in which the battery case body 61 and the sealing lid 62 are integrated is formed while electrically insulating the battery case body 61 and the sealing lid 62. Thereby, the battery 1 of the present Example 1 is completed.

( Reference Example 1 )
Next, the battery 101 according to Reference Example 1 will be described. The battery 101 of the reference example 1 is different from the battery 1 of the example 1 only in that the separator winding part 30 is integrally hardened by welding, and is otherwise the same as the example 1. Therefore, here, the description will focus on the points different from the first embodiment, and the description of the same points will be omitted or simplified.

In the battery 101 of the present reference example 1 , the separator winding part 30 is integrally hardened by welding the separators (the first separator 31 and the second separator 35) forming the separator winding part 30 (one lump and Have been). Specifically, separators adjacent to each other in the radial direction (the first separator 31 and the second separator 35) are welded together in the separator winding part 30 to solidify the separator winding part 30 as one body (a single lump). ). In other words, by welding, separators adjacent to each other in the radial direction (first separator 31 and second separator 35) are joined in the separator winding part 30, and the separator winding part 30 is integrally hardened (as a lump. )

  By separating and solidifying the separator winding part 30 by welding the separators (the first separator 31 and the second separator 35), the separator winding part 30 can be made a strong shaft core. As a result, the separator winding part 30 causes the winding electrode body 40 to deform toward the inside (center side) as the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20) expands and contracts. As a result, deformation of the wound electrode body 40 toward the inner side (center side) can be suppressed.

For this reason, in the battery 101 of the first reference example , loose winding (the positive electrode plate 10 and the negative electrode plate 20) due to the expansion / contraction of the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20). , Loosening of the winding of the first separator 31 and the second separator 35) can be suppressed. Thereby, it is possible to prevent the distance between the positive electrode plate 10 and the negative electrode plate 20 adjacent to each other with the separator (the first separator 31 or the second separator 35) interposed therebetween, and as a result, the battery internal resistance increases. And a decrease in battery capacity can be suppressed.

  Furthermore, “buckling of the wound electrode body 40” due to repeated expansion and contraction of the wound electrode body 40 (the positive electrode plate 10 and the negative electrode plate 20) can also be suppressed. Thereby, the fracture | rupture of the positive electrode plate 10, the negative electrode plate 20, the 1st separator 31, and the 2nd separator 35 which comprises the winding electrode body 40 can be suppressed, As a result, the internal short circuit (the positive electrode plate 10 and a negative electrode accompanying the said fracture | rupture) Contact with the plate 20) can be suppressed.

Next, a method for manufacturing the battery 101 will be described below.
First, similarly to Example 1, in the winding process, only the separators (the first separator 31 and the second separator 35) are wound a plurality of times from the winding start position SP located on the innermost side of the wound electrode body 40. Thus, a wound electrode body 40 having a “separator wound portion 30” is formed (see FIGS. 4, 5, and 8).

  Next, the process proceeds to the welding step, and as shown in FIG. 9, a rod-shaped heater 90 (for example, a sheathed heater) is inserted into the cylinder of the wound electrode body 40 (specifically, inside the separator wound portion 30). The separator winding part 30 (the first separator 31 and the second separator 35 constituting the separator winding part 30) is melted (softened). For example, the separator winding part 30 (the 1st separator 31 and the 2nd separator 35 which comprises this) is heated to 120 to 200 degreeC with the heater 90, and is fuse | melted. The heating time is, for example, about 3 to 10 seconds.

  Then, the heater 90 is taken out from the cylinder of the wound electrode body 40, the melted separator wound portion 30 (the first separator 31 and the second separator 35 constituting the heater) is cooled, and the separator wound portion 30 is removed. Harden. Thereby, the separator (the 1st separator 31 and the 2nd separator 35) which comprises the separator winding part 30 welds. Specifically, the separators (the first separator 31 and the second separator 35) adjacent to each other in the radial direction (the left-right direction in FIGS. 8 and 9) are joined by welding. In this manner, the “separator winding portion 30 that is integrally hardened by welding the separators (the first separator 31 and the second separator 35)” can be formed.

Next, in the same manner as in Example 1, the positive electrode current collector 71 is welded to the positive electrode winding part 44, and the negative electrode current collector 72 is welded to the negative electrode winding part 46. Thereafter, the wound electrode body 40 in which the positive electrode current collecting member 71 and the negative electrode current collecting member 72 are welded is accommodated in the battery case body 61 (see FIG. 3). Next, the negative electrode current collecting member 72 is welded to the bottom 61 b of the battery case body 61. Further, one end portion of the connection member 53 is welded to the positive electrode current collecting member 71, and the other end portion of the connection member 53 is welded to the ceiling portion 62 b of the sealing lid 62. Next, after injecting the electrolyte into the battery case main body 61, the battery case main body is disposed in a state where the sealing lid 62 in which the gasket 69 is disposed at the outer peripheral end 62 c is disposed inside the opening 61 </ b> H of the battery case main body 61. The opening 61H of 61 is crimped. Thereby, the battery 101 of the reference example 1 is completed.

In the above, the present invention has been described with reference to the first embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. .

  For example, in Example 1, after forming the wound electrode body 40 in the winding step, an adhesive is applied to the inner peripheral surface 30b of the separator winding portion 30 to form the separator (first first winding 30). The separator 31 and the second separator 35) were infiltrated (impregnated) with the adhesive to form the “separator winding portion 30 solidified integrally with the adhesive”.

  However, before winding the separators (the first separator 31 and the second separator 35) in the winding step, a portion of the separator winding portion 30 that is to be configured in advance (from one end of the separator of the separator to the separator winding). An adhesive may be applied to the surface of the portion 30 having a winding length), and a separator with an adhesive may be wound. Even in this case, the “separator winding portion solidified by an adhesive” can be formed.

  Moreover, you may make it use a sheet-like semi-hardened adhesive (for example, prepreg) as an adhesive agent. Specifically, in the winding step, the sheet-like semi-cured adhesive is sandwiched between the first separator 31 and the second separator 35 so as to be wound together with the first separator 31 and the second separator 35. You may make it form "the separator winding part 30 containing a semi-hardened adhesive agent" by which the hardening adhesive agent was wound. Thereafter, by curing the semi-cured adhesive, it is possible to form “a separator wound portion integrally solidified with an adhesive”.

DESCRIPTION OF SYMBOLS 1,101 Battery 10 Positive electrode plate 20 Negative electrode plate 30 Separator winding part 31 1st separator 35 2nd separator 40 Winding electrode body SP Winding start position

Claims (1)

A wound electrode body obtained by winding a positive electrode plate, a negative electrode plate, and a separator into a cylindrical shape,
A winding electrode having a separator winding portion formed by winding only the separator among the positive electrode plate, the negative electrode plate, and the separator from a winding start position located on the innermost side of the winding electrode body. A battery comprising a body,
The separator winding part is a battery in which the separators adjacent to each other in the radial direction are integrally hardened by bonding with an adhesive .

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