JP6206039B2 - Method for manufacturing power storage element - Google Patents

Description

  The present invention relates to a power storage element having a wound electrode body in which a positive electrode, a negative electrode, and a separator are laminated and wound, and a method thereof.

  2. Description of the Related Art Conventionally, some power storage devices including batteries such as lithium ion batteries have a wound electrode body in which a positive electrode, a negative electrode, and a separator are laminated and wound. In a power storage device having such a wound electrode body, the separator is fixed at the end of the outermost winding of the wound electrode body. At this time, as a method of fixing the separator at the position of the winding end on the outermost periphery of the wound electrode body, there is a method of fixing using an adhesive tape.

JP-A-11-250873

  However, a separator in which a heat-resistant layer such as a heat-resistant filler is coated on one side of the separator for the purpose of maintaining insulation between the positive electrode and the negative electrode when heat is generated in an abnormal condition (hereinafter referred to as “heat-resistant coated separator”). ) Has been devised. When such a heat-resistant coated separator is applied to a wound electrode body, the adhesive tape is difficult to adhere to the heat-resistant layer of the heat-resistant coated separator, and a state in which a tensile force is applied to the wound electrode body. It is difficult to fix with adhesive tape. For this reason, the outermost peripheral part of the wound electrode body is likely to be loosened, and a space (distance) is likely to be vacant between the positive electrode and the negative electrode of the wound electrode body, leading to a decrease in the performance of the storage element.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a power storage element that can ensure safety in an abnormal state without degrading performance.

  In order to achieve the above object, a power storage device according to one embodiment of the present invention includes an electrode body in which a positive electrode, a negative electrode, and a separator are stacked and wound, and an outermost end portion of the electrode body And the separator has a base material layer and a heat-resistant layer containing inorganic particles disposed on the base material layer, and the electrode body has an outer peripheral surface. Is the heat-resistant layer of the separator, and the separator includes the first layer in the outer peripheral surface of the electrode body and the base layer in the second region having a circumferential position different from the first region. At least a part of the adhesive tape is exposed, and the adhesive tape is bonded in the first region and the second region across the outermost peripheral edge of the electrode body, so that the outermost periphery of the electrode body is The end is fixed.

  According to this, the adhesive tape is bonded to the outermost end of the electrode body in the first region and the second region where at least a part of the base material layer is exposed, thereby The end is fixed. That is, since the adhesive tape is bonded in the first region and the second region that are easily bonded, it can be fixed in a state in which a tensile force is applied to the outermost end of the electrode body. For this reason, it can prevent that the outermost periphery part of a winding type electrode body loosens, and can suppress a performance fall in the electrical storage element which employ | adopted the separator provided with the heat resistant layer. That is, in the electricity storage device of the present invention, safety in an abnormal state can be ensured without degrading performance.

  For example, the first region and the second region may be adjacent to each other with the outermost edge of the electrode body as a boundary.

  According to this, since the first region and the second region where the base material layer to which the adhesive tape is easily bonded are exposed are continuous, the adhesive tape can be used without interposing a region that is difficult to be bonded therebetween. Can be fixed to the outer peripheral surface of the electrode body. For this reason, the outermost periphery edge part of an electrode body can be more reliably fixed to the outer peripheral surface of an electrode body.

  Further, for example, the adhesive tape may be arranged in a region included in the first region and the second region.

  For this reason, all the adhesion surfaces of an adhesive tape can be utilized for fixation of the outermost periphery of an electrode body, and the outermost periphery edge part of an electrode body can be fixed to the outer peripheral surface of an electrode body more reliably.

  Further, the present invention provides a separator comprising a positive electrode and a negative electrode, a base material layer, and a separator having a heat resistant layer containing inorganic particles disposed on the base material layer. The winding step for forming the electrode body by winding the electrode body to form a surface, the first region of the separator region to be the outer peripheral surface of the electrode body, and the first region differ in circumferential position. An exposure step of exposing at least part of the base material layer in the second region; and the first region exposed in the exposure step and the first of the electrode bodies formed in the winding step. It may be realized as a method for manufacturing an electric storage element including a fixing step of fixing an outermost end of the electrode body by bonding an adhesive tape in two regions.

  According to the electricity storage device according to the present invention, since it can be easily held in a state where a tensile force is applied to the electrode body, it is possible to suppress a decrease in performance of the electricity storage device.

It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows each component with which the main body of the container of the electrical storage element which concerns on embodiment of this invention isolate | separates, and an electrical storage element is provided. It is a figure for demonstrating the structure of an electrode body. It is a perspective view which shows the external appearance of an electrode body. It is sectional drawing of an electrode body, (a) is VV sectional drawing of the electrode body of FIG. 4, (b) is the elements on larger scale of the A1 part of (a). It is a flowchart for demonstrating the manufacturing method of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows the external appearance of the electrode body which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are examples, and are not intended to limit the present invention. The invention is specified by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

(Embodiment)
FIG. 1 is a perspective view schematically showing the external appearance of the energy storage device according to the embodiment of the present invention. FIG. 2 is a perspective view showing each component included in the power storage element by separating the main body of the container of the power storage element according to the embodiment of the present invention.

  The storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte battery such as a lithium ion secondary battery.

  As shown in the figure, the electricity storage element 10 includes a container 100, a positive electrode terminal 200, a negative electrode terminal 300, and a container 100. In addition, an electrode body 140, a positive electrode current collector 120, and a negative electrode current collector 130 are disposed inside the container 100.

  Note that a liquid such as an electrolytic solution is sealed inside the container 100 of the power storage element 10, but the liquid is not shown. Moreover, the electrical storage element 10 is not limited to a non-aqueous electrolyte battery, and may be a secondary battery other than the non-aqueous electrolyte battery or a capacitor.

  The container 100 includes a main body 111 having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid 110 that closes an opening of the main body. The container 100 can seal the inside by welding the lid body 110 and the main body 111 after accommodating the electrode body 140 and the like therein. In the present embodiment, the alignment direction of the main body 111 and the lid body 110 is the Z-axis direction, the alignment direction of the positive electrode terminal 200 and the negative electrode terminal 300 is the X-axis direction, and a direction perpendicular to the vertical direction and the horizontal direction. In the Y-axis direction.

  The electrode body 140 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, the electrode body 140 is formed by winding a layered arrangement so that a separator is sandwiched between a negative electrode and a positive electrode so that the whole becomes an oval shape. In addition, in the same figure, although the ellipse shape was shown as a shape of the electrode body 140, circular shape or elliptical shape may be sufficient. The detailed configuration of the electrode body 140 will be described later.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 140, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 140. In other words, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 140 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 140, It is an electrode terminal made of metal for introducing. Further, the positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid body 110 disposed above the electrode body 140.

  The positive electrode current collector 120 is disposed between the positive electrode of the electrode body 140 and the side wall of the container 100, and has a conductivity and rigidity that are electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 140. It is. The positive electrode current collector 120 is made of the same material as the positive electrode of the electrode body 140, and is specifically formed of aluminum or an aluminum alloy.

  The negative electrode current collector 130 is disposed between the negative electrode of the electrode body 140 and the side wall of the container 100, and has a conductivity and rigidity that are electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 140. It is. The negative electrode current collector 130 is made of the same material as the negative electrode of the electrode body 140, and is specifically formed of copper or a copper alloy.

  FIG. 3 is a diagram for explaining the structure of the electrode body. FIG. 4 is a perspective view showing an external appearance of the electrode body. FIG. 5 is a cross-sectional view of the electrode body. Specifically, (a) of FIG. 5 is a VV cross-sectional view of the electrode body of FIG. 4, and (b) of FIG. 5 is a partially enlarged view of a portion A1 of (a) of FIG. is there.

  As shown in FIGS. 3 to 5, the electrode body 140 is formed by laminating and winding a positive electrode 141 and a negative electrode 142 each having an active material applied on a surface thereof, and separators 143 and 144. That is, the electrode body 140 is wound so that the cross section becomes an oval shape with the positive electrode 141, the first separator 143, the negative electrode 142, and the second separator 144 laminated in this order. Become. And as shown in FIG. 4, the outermost edge part of the electrode body 140 is being fixed with the adhesive tape 150 in multiple places (this embodiment 3 places). Note that the end of the electrode body 140 fixed by the adhesive tape 150 is not limited to a plurality of locations, and may be a single location.

  The positive electrode 141 is obtained by forming a positive electrode active material layer on the surface of a long strip-shaped positive electrode current collector foil made of aluminum or an aluminum alloy. In addition, the positive electrode 141 used for the electrical storage element 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

  The negative electrode 142 is obtained by forming a negative electrode active material layer on the surface of a long strip negative electrode current collector foil made of copper or a copper alloy. Note that the negative electrode 142 used in the electricity storage device 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

  The first separator 143 and the second separator 144 are long strip separators arranged between the positive electrode 141 and the negative electrode 142 as shown in FIG. The first separator 143 and the second separator 144 are heat-resistant coated separators each having a base material layer 143a, 144a and a heat-resistant layer 143b, 144b.

  The base material layers 143a and 144a are microporous sheets containing a thermoplastic resin.

  The heat-resistant layers 143b and 144b are layers different in material from the base material layers 143a and 144a, which are disposed on one surface of the base material layers 143a and 144a. In the present embodiment, the heat-resistant layers 143b and 144b are layers coated on one surface of the base material layers 143a and 144a. Here, the heat resistant layer includes, for example, a mixture of inorganic particles such as alumina and a binder such as polyvinylidene fluoride (PVdF), or a heat resistant resin such as polydivinylbenzene (PDVB) and polyamide.

  That is, each of the first separator 143 and the second separator 144 includes the base material layers 143a and 144a and the heat resistant layers 143b and 144b including inorganic particles disposed on the base material layers 143a and 144a. The first separator 143 and the second separator 144 are stacked so that the heat-resistant layers 143b and 144b face the positive electrode 141, and the base layers 143a and 144a face the negative electrode 142.

  A winding core (not shown) made of polypropylene, polyethylene, or the like is disposed on the innermost periphery of the electrode body 140. In the electrode body 140, the first separator 143 and the second separator 144 are welded and fixed to the winding core, the positive electrode 141, the first separator 143, the negative electrode 142, and the second separator 144 are laminated and wound. It is constituted by being done. As shown in FIGS. 3 and 4, the outer peripheral surface of the outermost periphery (the last one) of the electrode body 140 is constituted by the heat-resistant layer 144 b of the second separator 144.

  The second separator 144 of the electrode body 140 is based on the first area R1 and the second area R2 on the outer peripheral surface of the electrode body 140 as shown in the hatched area of FIG. 4 and FIG. At least a part of the material layer 144a is exposed. That is, the second separator 144 has a portion where the base material layer 144a is exposed in the first region R1 and the second region R2, and a heat resistant layer 144b in a region other than the first region R1 and the second region R2. A portion where the thin heat-resistant layer 144b remains is mixed. Here, the first region R <b> 1 is a region at the end of the second separator 144 on the outermost periphery of the electrode body 140. 2nd area | region R2 is an area | region where the position of the circumferential direction (winding direction) differs from 1st area | region R1 in the outer peripheral surface of the electrode body 140, Comprising: The edge part (1st area | region R1) of the said outermost periphery is an electrode body. This is a region in the second separator 144 that overlaps the outer peripheral surface of 140. The first region R1 and the second region R2 are adjacent to each other with the outermost edge L1 of the electrode body 140 as a boundary. That is, the first region R <b> 1 and the second region R <b> 2 in the second separator 144 are continuous with the outermost peripheral end of the electrode body 140 overlapping the outer peripheral surface of the electrode body 140.

  The adhesive tape 150 is bonded in the first region R1 and the second region R2 across the outermost peripheral edge L1 of the electrode body 140 (that is, the edge L1 of the second separator 144), so that the electrode body 140 The outermost end is fixed to the outer peripheral surface of the electrode body 140. Further, the adhesive tape 150 is bonded to the first region R1 and the second region R2 of the second separator 144, thereby fixing the outermost end of the electrode body 140. That is, the adhesive tape 150 is disposed in a region included in the first region R1 and the second region R2 in the second separator 144.

  Next, a method for manufacturing the electricity storage device 10 having the electrode body 140 will be described with reference to FIGS.

  As shown in FIG. 6, first, the electrode body 140 is formed by winding the positive electrode 141 and the negative electrode 142 and the separators 143 and 144 while laminating them (S1: winding step).

  Next, at least a part of the base material layer 144a is exposed by peeling off the heat-resistant layer 144b in the first region R1 and the second region R2 on the outer peripheral surface of the electrode body 140 formed in the winding step S1 ( S2: exposure step). In the exposure step S2, specifically, the heat-resistant layer 144b is bonded to, for example, an adhesive tape (different from the adhesive tape 150) at the outermost peripheral end portion of the wound electrode body 140 and its peripheral region. The peeling may be performed by repeating once or a plurality of times, or may be performed by removing the heat-resistant layer 144b in the region by, for example, brushing. That is, at least the base material layer 144a in which the adhesive tape 150 is easily bonded among the second separators 144 in the outermost end portion of the electrode body 140 and the region of the outer peripheral surface of the electrode body 140 where the end portions overlap is at least. What is necessary is just to perform the process which exposes.

  Finally, in the first region R1 and the second region R2 of the second separator 144 exposed in the exposing step, the outermost end of the electrode body 140 is fixed by adhering the adhesive tape 150 (S3: fixed) Step).

  Thereby, the outermost end of the electrode body 140 is firmly fixed to the outer peripheral surface of the electrode body 140.

  According to the electricity storage device 10 according to the present exemplary embodiment, the adhesive tape 150 includes the first region R1 and the second region R2 in which at least a part of the base material layer 144a is exposed at the outermost end of the electrode body 140. By adhering with, the outermost end of the electrode body 140 is fixed. That is, since the adhesive tape 150 is bonded in the first region R1 and the second region R2 that are easily bonded, the adhesive tape 150 can be fixed in a state where a tensile force is applied to the outermost end of the electrode body 140. For this reason, it is possible to prevent the outermost peripheral portion of the wound electrode body 140 from being loosened, and in the power storage element 10 employing the separators 143 and 144 provided with the heat-resistant layer 144b, it is possible to suppress a decrease in performance. . In other words, the power storage element 10 can ensure safety in an abnormal state without degrading performance.

  Moreover, according to the electrical storage element 10 according to the present embodiment, the first region R1 and the second region R2 where the base material layer 144a to which the adhesive tape 150 is easily bonded are exposed are continuous. For this reason, the adhesive tape 150 can fix the outermost end of the electrode body 140 to the outer peripheral surface of the electrode body 140 without interposing a region that is difficult to be bonded. For this reason, the end part of the outermost periphery of the electrode body 140 can be fixed to the outer peripheral surface of the electrode body 140 more reliably.

  Moreover, according to the electrical storage element 10 which concerns on this Embodiment, the area of the adhesive tape 150 is below the area which combined 1st area | region R1 and said 2nd area | region R2. For this reason, all the adhesive surfaces of the adhesive tape 150 can be used for fixing the outermost periphery of the electrode body 140, and the end portion of the outermost periphery of the electrode body 140 can be more securely fixed to the outer peripheral surface of the electrode body 140. .

(Modification)
(1)
In the electricity storage device 10 in the above embodiment, the first region R1 and the second region R2 of the electrode body 140 are adjacent to each other with the outermost edge L1 of the electrode body 140 as a boundary. For example, as shown in FIG. 7, by forming the second region R12 at a position away from the outermost edge L1 of the electrode body 140a, the first region R11 and the second region R12 are not adjacent to each other. Also good. The first region R11 shown in FIG. 7 is formed in a region including the outermost edge L1 of the electrode body 140a, but is formed at a position away from the outermost edge L1 of the electrode body 140a. May be. Further, the first region R11 and the second region R12 shown in FIG. 7 are formed on the surface of the second separator 144 on the Y axis minus direction side, but may be formed on the surface of the Y axis plus direction side. Good. Further, the first region R11 and the second region R12 may be continuously formed from the second region R12 to the first region R11 of the outermost peripheral edge L1 of the second separator 144.

  As shown in FIG. 7, even if the first region R11 and the second region R12 are formed at positions separated from each other, the adhesive tape 150 has the first region R11 and the second region R12 at the outermost edge L1 of the electrode body 140a. Therefore, the end of the electrode body 140a can be fixed to the outer peripheral surface of the electrode body 140a.

(2)
In the electricity storage device 10 in the above embodiment, the adhesive tape 150 is provided in a region included in the first region R1 and the second region R2, but not limited thereto, the first region R1 and the second region. For example, it may be provided so as to protrude from R2 to the outside in the Z-axis direction.

(3)
In the electricity storage device 10 according to the above embodiment, the first separator 143 and the second separator 144 are configured such that the heat-resistant layers 143b and 144b are coated on one surface of the base material layers 143a and 144a. Not limited to this. That is, at least one of the first separator and the second separator may be configured such that the heat-resistant layers are coated on both surfaces of the base material layer.

(4)
In the method for manufacturing power storage element 10 according to the above embodiment, the winding step S1 and the exposure step S2 are performed in this order, but the order of the winding step S1 and the exposure step S2 may be switched. That is, by estimating the positions of the first region R1 and the second region R2 that are regions on the second separator 144 that are the outer peripheral surfaces of the electrode body 140 in advance, the estimated first region R1 on the second separator 144 and In the second region R2, an exposure step for exposing at least a part of the base material layer 144a may be performed before the winding step.

(5)
In the method of manufacturing the electricity storage device 10 according to the above embodiment, the second separator 144 includes the first region R1 and the second region R2, the portion where the base material layer 144a is exposed, the first region R1 and the second region R2. A portion where the heat-resistant layer 144b thinner than the heat-resistant layer 144b in the region other than the region R2 remains is mixed, but the present invention is not limited to this. For example, the second separator 144 may be formed such that only the base material layer 144a is exposed in the first region R1 and the second region R2. That is, the second separator in this case may be formed so that there is no heat-resistant layer 144b in the first region R1 and the second region R2.

  The power storage element according to one embodiment of the present invention is useful as a power storage element that can ensure safety in an abnormal state without causing deterioration in performance.

DESCRIPTION OF SYMBOLS 10 Storage element 100 Container 110 Cover body 111 Main body 120 Positive electrode current collector 130 Negative electrode current collector 140, 140a Electrode body 141 Positive electrode 142 Negative electrode 143 First separator 143a Base material layer 143b Heat resistant layer 144 Second separator 144a Base material layer 144b Layer 150 Adhesive tape 200 Positive electrode terminal 300 Negative electrode terminal L1 Edge R1, R11 First region R2, R12 Second region

Claims (1)

A positive electrode and a negative electrode, a base material layer, and a separator having a heat resistant layer containing inorganic particles disposed on the base material layer are laminated, and the heat resistant layer of the separator is wound so as to be an outer peripheral surface. A winding step of forming an electrode body by turning;
An exposing step of exposing at least a part of the base material layer in a first region of the separator region which is an outer peripheral surface of the electrode body and a second region having a circumferential position different from the first region; ,
Out of the electrode bodies formed in the winding step, in the first region and the second region exposed in the exposing step, by adhering an adhesive tape, the outermost end of the electrode body And a fixing step for fixing the power storage element.

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