JP6459505B2 - Electricity storage element - Google Patents

Description

  The present invention relates to an energy storage device including an electrode body formed by winding an electrode plate, an exterior body that houses the electrode body, and a spacer that is disposed between the electrode body and the exterior body.

  In a power storage element having a so-called wound electrode body formed by winding an electrode plate, heat generated in a current collector connecting the electrode body and the electrode terminal is efficiently radiated and the power storage In order to reinforce the side surface of the exterior body of the element, a method of arranging a current collector on the outer peripheral side surface of the electrode body is known (for example, see Patent Document 1).

JP 11-339757 A

  However, in such a method, a spacer such as a current collector disposed between the electrode body and the exterior body by virtue of the vibration of the electrode body inside the exterior body in an environment where the storage element vibrates. There is a possibility that the physical load applied to the head increases. Such an increase in load becomes a factor causing damage to the spacer.

  The present invention has been made to solve the above-described problem, and an object thereof is to provide a power storage element that can suppress spacer damage.

  In order to achieve the above object, an energy storage device according to one embodiment of the present invention includes an electrode body formed by winding an electrode plate, an exterior body that houses the electrode body, the electrode body, and the electrode body. An electrical storage element including a spacer disposed between the outer body and the electrode body, the electrode body having a pair of opposed flat portions and a curved portion connecting the pair of flat portions, In the flat part, only a part of the flat part is covered, and at least a part of the covering part is arranged at an end of the flat part in the winding direction of the electrode body.

  The spacer may be a current collector that connects the electrode body and the electrode terminal.

  Further, at least a part of the spacer may be disposed at a boundary between the flat portion and the curved portion of the electrode body.

  Moreover, the said spacer may have a part arrange | positioned toward the center side of the said flat part in the said winding direction.

  The spacer may have an elongated extending portion extending in a direction parallel to the winding axis of the electrode body.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element which can suppress damage to a spacer can be provided.

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 the component arrange | positioned inside the exterior body of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows the structure of the electrode body which concerns on embodiment of this invention. It is sectional drawing in the IIIB-IIIB cross section of FIG. 3A. It is a figure for demonstrating the bias | inclination of deformation resistance in the electrode body which concerns on embodiment of this invention. It is a figure which shows the shape of the positive electrode collector which concerns on embodiment of this invention, and an electrode body, (a) is a side view, (b) is sectional drawing in the Vb-Vb cross section of (a), (c) is It is a bottom view. It is sectional drawing of the electrical storage element which concerns on embodiment of this invention. In embodiment of this invention, it is a bottom view which shows the shape of a positive electrode collector and an electrode body when the flat part in the winding direction of an electrode body and the center part are crushed further. It is a side view which shows the shape of the positive electrode collector which concerns on the modification 1 of embodiment of this invention, and an electrode body. It is sectional drawing in the IX-IX cross section of FIG. It is a perspective view which shows the component arrange | positioned inside the exterior body of the electrical storage element which concerns on the modification 2 of embodiment of this invention. It is sectional drawing in the XI-XI cross section of FIG. It is a side view which shows the shape of the positive electrode collector which concerns on the modification 3 of embodiment of this invention, and an electrode body. It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on the modification 4 of embodiment of this invention.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, 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 described as optional constituent elements that constitute a more preferable embodiment. Moreover, in each figure, a dimension etc. do not correspond exactly | strictly.

(Embodiment)
First, the structure of the electrical storage element 10 is demonstrated in detail.

  FIG. 1 is a perspective view schematically showing an external appearance of a power storage device 10 according to an embodiment of the present invention. Moreover, FIG. 2 is a perspective view showing components arranged inside exterior body 100 of power storage element 10 according to the embodiment of the present invention. Specifically, FIG. 2 is a perspective view illustrating a configuration in a state where the main body 111 of the outer package 100 is separated from the power storage element 10. 3A is a perspective view showing a configuration of electrode body 140 according to the exemplary embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB in FIG. 3A.

  In FIG. 1 and the subsequent drawings, for convenience of explanation, the Z-axis direction is shown as the vertical direction, and there are places where the Z-axis direction is described as the vertical direction. The axial direction is not always the vertical direction.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the electric storage element 10 is applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an artificial satellite, or the like. In addition, the electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it.

  As shown in FIG. 1, the power storage element 10 includes an exterior body 100, a positive electrode terminal 200, and a negative electrode terminal 300. As shown in FIG. 2, a positive electrode current collector 120 and an electrode body 140 are accommodated (accommodated) inside the exterior body 100. Further, although not shown in FIG. 2, a negative electrode current collector 130 (see FIG. 5) is further accommodated inside the outer package 100.

  In addition to the above components, a spacer disposed between the electrode body 140 and the inner wall of the exterior body 100, a safety valve for releasing the pressure when the pressure in the exterior body 100 rises, or an electrode An insulating film or the like that wraps the body 140 or the like may be disposed. In addition, a liquid such as an electrolytic solution (nonaqueous electrolyte) is sealed in the exterior body 100 of the power storage element 10, but the liquid is not illustrated. In addition, as long as the electrolyte solution enclosed with the exterior body 100 does not impair the performance of the electrical storage element 10, there is no restriction | limiting in particular in the kind, Various things can be selected.

  The exterior body 100 includes a main body 111 having a long cylindrical shape and a bottom, and a lid body 110 that is a plate-like member that closes an opening of the main body 111. In addition, the exterior body 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. The material of the lid 110 and the main body 111 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, or aluminum alloy.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 140 via the positive electrode current collector 120, and the negative electrode terminal 300 is the negative electrode of the electrode body 140 via the negative electrode current collector 130. The electrode terminal is electrically connected to. 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. 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 terminal 200 and the negative electrode terminal 300 are formed of aluminum or an aluminum alloy.

  The positive electrode current collector 120 is a member that is disposed between the electrode body 140 and the exterior body 100 and has conductivity and rigidity that connects the electrode body 140 and the positive electrode terminal 200. Specifically, the positive electrode current collector 120 covers only a part of the flat portions 143 and 144 in flat portions 143 and 144 (described later) of the electrode body 140, and at least a part of the covered portion is an electrode. It arrange | positions at the edge parts 143a, 143b, 144a, and 144b of the flat parts 143 and 144 in the winding direction (circular direction of an ellipse) of the body 140. FIG. More specifically, the positive electrode current collector 120 is disposed at the end portion 144a in the present embodiment. In the following, the winding direction of the electrode body 140 may be simply referred to as “winding direction”.

  The positive electrode current collector 120 is joined to a positive electrode side end 141 (to be described later) of the electrode body 140 by welding or the like at the bottom portion (a portion on the negative side in the Z-axis direction) of the power storage element 10. Note that the positive electrode current collector 120 is made of aluminum or an aluminum alloy, as with the positive electrode current collector foil of the positive electrode. A detailed configuration of the positive electrode current collector 120 will be described later.

  Further, the negative electrode current collector 130 (see FIG. 5) is disposed between the negative electrode of the electrode body 140 and the exterior body 100, and has conductivity and rigidity for connecting the electrode body 140 and the negative electrode terminal 300. It is a member. The negative electrode current collector 130 is joined to the negative electrode side end portion 142 of the electrode body 140 by welding or the like in the upper portion (the Z-axis direction plus side portion) of the power storage element 10. Note that the negative electrode current collector 130 is made of copper, a copper alloy, or the like, similarly to the negative electrode current collector foil.

  The electrode body 140 is a power generation element capable of storing electricity, and includes a positive electrode, a negative electrode, and a separator, and the positive electrode, the negative electrode, and the separator are stacked in the X-axis direction and the Y-axis direction. Specifically, the electrode body 140 is a wound electrode body formed by winding a positive electrode, a negative electrode, and a separator, and is electrically connected to the positive electrode current collector 120 and the negative electrode current collector 130. .

The positive electrode is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode base material layer that is a long strip-shaped metal foil made of aluminum, an aluminum alloy, or the like. In addition, as a positive electrode active material used for a positive electrode active material layer, if it is a positive electrode active material which can occlude / release lithium ion, a well-known material can be used suitably. For example, as a positive electrode active material, a polyanion compound such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, Spinel compounds such as lithium manganate, lithium transition metal oxides such as LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and the like can be used.

The negative electrode is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode base material layer that is a long strip-shaped metal foil made of copper, a copper alloy, or the like. In addition, as a negative electrode active material used for a negative electrode active material layer, if it is a negative electrode active material which can occlude-release lithium ion, a well-known material can be used suitably. For example, as the negative electrode active material, lithium metal, lithium alloy (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy), and lithium can be used. Alloys that can be occluded / released, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₅ O _12, etc.) ) And polyphosphoric acid compounds.

  The separator is a microporous sheet made of resin. In addition, the separator used for the electrical storage element 10 is not particularly different from that conventionally used, and any known material can be used as long as it does not impair the performance of the electrical storage element 10. In addition, as the electrolytic solution (nonaqueous electrolyte) sealed in the outer package 100, there is no particular limitation on the type thereof as long as the performance of the power storage element 10 is not impaired, and various types can be selected.

  Here, the electrode body 140 is formed by winding a layered arrangement so that a separator is sandwiched between a positive electrode and a negative electrode. Specifically, in the electrode body 140, a positive electrode and a negative electrode are wound while being shifted from each other in the direction of the winding axis via a separator. And the positive electrode and the negative electrode are the portions where the active material is not applied and the base material layer is exposed (the active material layer is not formed) at the edge portions in the respective shifted directions (the active material layer non-formed portion) )have.

  The winding axis is a virtual axis that becomes a central axis when winding the positive electrode, the negative electrode, and the like. In this embodiment, the winding axis is a straight line that passes through the center of the electrode body 140 and is parallel to the Z-axis direction. is there.

  Specifically, the electrode body 140 has an end portion 141 on the positive electrode side where an active material layer non-forming portion of the positive electrode is laminated at one end in the winding axis direction (end portion on the negative side in the Z-axis direction). Yes. Similarly, the electrode body 140 has a negative electrode-side end portion 142 in which a negative electrode active material layer non-formation portion is laminated at the other end in the winding axis direction (Z-axis direction positive side end portion). ing.

  In addition, the electrode body 140 has a flat (collapsed) shape in a direction orthogonal to the winding axis direction (Y-axis direction in the present embodiment). Thereby, since the electrode body 140 has an oval shape when viewed from the winding axis direction, the oval straight portion has a flat shape and the oval curved portion has a curved shape. . For this reason, as shown in FIG. 3B, the electrode body 140 has a pair of flat portions 143 and 144 facing each other and a pair of curved portions 145 and 146 facing each other.

  That is, the pair of flat portions 143 and 144 and the pair of curved portions 145 and 146 are portions formed by winding the positive electrode, the negative electrode, and the separator. In addition, the pair of flat portions 143 and 144 and the pair of curved portions 145 and 146 are portions disposed in a region where a positive electrode or negative electrode active material is formed.

  Specifically, the pair of flat portions 143 and 144 are portions having flat shapes arranged on the positive side and the negative side in the Y-axis direction of the electrode body 140 in the region where the positive or negative active material is formed. And are arranged opposite to each other.

  The pair of curved portions 145 and 146 are portions having a curved shape connecting the pair of flat portions 143 and 144 in the region where the positive or negative electrode active material is formed, and are disposed to face each other. That is, the bending portion 145 is a substantially U-shaped portion having one end connected to one end of the flat portion 143 and the other end connected to one end of the flat portion 144, and is disposed on the negative side of the electrode body 140 in the X-axis direction. Has been. The bending portion 146 is a substantially U-shaped portion having one end connected to the other end of the flat portion 143 and the other end connected to the other end of the flat portion 144, and is on the plus side of the electrode body 140 in the X-axis direction. Is arranged.

  In other words, the flat portion 143 has one end connected to one end of the bending portion 145 and the other end connected to one end of the bending portion 146. The flat portion 144 has one end connected to the other end of the bending portion 145 and the other end connected to the other end of the bending portion 146.

  The wound electrode body 140 configured in this way has a portion that is relatively easily deformed and a portion that is relatively difficult to deform. That is, the electrode body 140 has a biased deformation resistance (hardness to deform).

  FIG. 4 is a diagram for explaining a bias in deformation resistance in the electrode assembly 140 according to the present embodiment. Specifically, the drawing is a cross-sectional view of the electrode body 140 in the IIIB-IIIB cross section of FIG. 3A when the pressing force Fa is uniformly applied to the electrode body 140 from the outside.

  The wound electrode body 140 is less likely to deform in the stacking direction at the curved portions 145 and 146 than the flat portions 143 and 144, and the direction of the winding axis of the electrode body 140 (direction parallel to the Z axis) From the viewpoint of deformation, it is harder to deform in the shorter direction than the longitudinal direction. Thereby, the electrode body 140 becomes difficult to deform | transform in the edge parts 143a, 143b, 144a, and 144b of the flat parts 143 and 144. FIG.

  In particular, the electrode body 140 is less likely to be deformed at the boundary between the flat portions 143 and 144 and the curved portions 145 and 146 among the end portions 143a, 143b, 144a, and 144b.

  As a result, as shown in the figure, when the pressing force Fa is uniformly applied to the electrode body 140 from the outside, the electrode body 140 is viewed from the direction of the winding axis (Z-axis direction). A shape in which the axial thickness gradually increases from the central portion of the flat portions 143 and 144 toward the end portions 143a, 143b, 144a and 144b, and is maximized at the boundary between the flat portions 143 and 144 and the curved portions 145 and 146. It becomes.

  Here, for example, the end portions 143a, 143b, 144a, and 144b of the flat portions 143 and 144 can be defined as portions having a large thickness due to the influence of the curved portions 145 and 146 in the flat portions 143 and 144. The end portions 143a and 144a located on the bending portion 145 side are seen from the boundary between the flat portions 143 and 144 and the bending portion 145 when viewed from the direction of the winding axis of the electrode body 140. It can be defined as a region within the distance of the radius r1 of the circle 145R formed by the outer shape. Similarly, the end portions 143b and 144b located on the bending portion 146 side can be defined by a circle determined by the outer shape of the bending portion 146.

  The radius of each circle formed by the outer shape of each of the bending portions 145 and 146 can be obtained by measuring the radius of each circle in a state where the electrode body 140 is taken out from the exterior body 100. Further, the boundary between each of the flat portions 143 and 144 and the curved portions 145 and 146 is defined as a position where the central angle of each circle formed by the outer shape of each of the curved portions 145 and 146 is substantially 180 °. be able to.

  Next, the positional relationship between the positive electrode current collector 120 and the electrode body 140 will be described while describing the configuration of the positive electrode current collector 120 in detail.

  5A and 5B are diagrams showing the shapes of the positive electrode current collector 120 and the electrode body 140 according to the embodiment of the present invention, wherein FIG. 5A is a side view, and FIG. 5B is a cross section taken along the Vb-Vb cross section of FIG. FIG. 4C is a bottom view. In addition, the figure is a figure which shows the structure in the state which isolate | separated the main body 111 of the exterior body 100 from the electrical storage element 10. FIG.

  As shown in FIGS. 2 and 5, in the present embodiment, the positive electrode current collector 120 covers only a part of the flat part 144 in the flat part 144, and at least a part of the covered part is a flat part. It is arranged at the end 144 a of 144. In the present embodiment, at least a part of the covered portion is arranged at the boundary between the flat portion 144 and the curved portion 145 of the electrode body 140.

  The positive electrode current collector 120 has a long elongated portion 121 extending in a direction (Z-axis direction) parallel to the winding axis of the electrode body 140. Furthermore, the positive electrode current collector 120 has a connection portion 122 connected to the positive electrode side end portion 141 which is one end portion of the flat portion 144 in the direction of the winding axis.

  The extending portion 121 extends from the positive electrode terminal 200 side to the positive electrode side end portion 141 of the electrode body 140, and is arranged at the end portion 144a in the present embodiment. That is, the extending portion 121 is disposed in the end portion 144a in a direction parallel to the winding axis of the electrode body 140 (Z-axis direction). Accordingly, a large contact area between the positive electrode current collector 120 and the end portion 144a can be secured.

  The connecting part 122 is arranged from the extending part 121 toward the center side of the flat part 144 in the winding direction. Specifically, the connecting portion 122 has a strip shape extending from the end portion of the extending portion 121 toward the center side of the electrode body 140 in the winding direction, and the end portion on the opposite side to the extending portion 121 has a bellows shape. It has a repeatedly bent shape.

  A portion of the connection portion 122 bent in a bellows shape (hereinafter referred to as a “bellows portion”) is connected and fixed to the end portion 141 on the positive electrode side of the electrode body 140. Specifically, in the end portion 141, the positive electrode active material layer non-forming portion is bundled for every plurality of layers (for example, every 20 layers). Each of these bundles is inserted into a recess formed in the bellows portion, and is connected and fixed to the bellows portion by, for example, ultrasonic welding, resistance welding or caulking.

  The bellows portion is disposed in a region adjacent to the flat portion 144 (region not adjacent to the curved portions 145 and 146) in the end portion 141 on the positive electrode side of the electrode body 140. That is, the positive electrode current collector 120 is connected and fixed to the electrode body 140 in a region adjacent to the flat portion 144 in the end portion 141 on the positive electrode side. Thereby, since the connection between the positive electrode current collector 120 and the electrode body 140 can be performed at a relatively flat portion, for example, connection work by ultrasonic welding, resistance welding, caulking, or the like can be easily performed.

  Here, as a result of intensive studies, the inventors of the present application have made positive electrode arranged between the electrode body and the exterior body by virtue of the vibration of the electrode body inside the exterior body in an environment where the storage element vibrates. It has been found that the physical load on the current collector may increase. Such an increase in load may cause a damage to the positive electrode current collector. In particular, this problem becomes remarkable in a power storage element mounted on, for example, an artificial satellite to which intense impact and vibration are applied.

  On the other hand, in the present embodiment, the positive electrode current collector 120 has the extending portion 121 disposed at the end portion 144a.

  FIG. 6 is a cross-sectional view of power storage element 10 according to the present embodiment. Specifically, FIG. 6 is a cross-sectional view of the electricity storage element 10 in a Vb-Vb cross section in FIG.

  As shown in the figure, at least a part of the positive electrode current collector 120 (in this embodiment, the extended portion 121) is disposed between the electrode body 140 and the exterior body 100 at the end portion 144a of the flat portion 144. Is done.

  As described above, the end portions 143 a, 143 b, 144 a, and 144 b of the flat portions 143 and 144 are more external than the other portions of the flat portions 143 and 144 when the electrode body 140 is accommodated in the external body 100. Is relatively strongly pressed by.

  Therefore, even in an environment where the storage element 10 vibrates, the end portions 143a, 143b, 144a, and 144b are more firmly fixed to the exterior body 100 than the other portions. That is, the electrode body 140 is firmly fixed to the exterior body 100 at the end portions 143a, 143b, 144a, and 144b.

  That is, the extending portion 121 of the positive electrode current collector 120 is firmly sandwiched between the electrode body 140 and the exterior body 100 by being disposed at the end portion 144a.

  As described above, in the present embodiment, the extending portion 121 of the positive electrode current collector 120 is disposed at a location where the electrode body 140 is firmly fixed to the exterior body 100. That is, the extending portion 121 is disposed in a portion where the electrode body 140 is difficult to move inside the exterior body 100 even in an environment where the power storage element 10 vibrates.

  Thereby, the physical load applied to the positive electrode current collector 120 due to the vibration of the electrode body 140 inside the exterior body 100 under an environment where the power storage element 10 vibrates can be reduced. Therefore, damage to the positive electrode current collector 120 can be suppressed.

  Further, the expansion and contraction of the electrode plate is repeated by repeating the charging and discharging of the electricity storage element 10. As a result, the shape of the electrode body 140 is greatly deformed from the time of manufacturing the power storage element 10. Even when the electrode body 140 is deformed as described above, the electrode body 140 is efficiently provided by including the positive electrode current collector 120 at any one of the end portions 143a, 143b, 144a, and 144b of the flat portions 143 and 144. Can be squeezed. For this reason, the movement of the electrode body 140 due to vibration of the power storage element 10 or the like can be suppressed. That is, when the electrode body 140 is deformed due to the expansion and contraction of the electrode plate as described above, the end portions 143a, 143b, 144a and 144b of the flat portions 143 and 144 are deformed so as to expand. By disposing 120, it is possible to press the electrode body 140 more strongly than disposing the positive electrode current collector 120 at another location.

  Hereinafter, an evaluation test of the electricity storage device 10 according to the present embodiment performed by the present inventors will be described.

  In this evaluation test, as a comparative example of the present embodiment, a positive electrode current collector is disposed at the center of flat portions 143 and 144 (portions excluding end portions 143a, 143b, 144a, and 144b) in the winding direction. An element was used.

First, each of the electricity storage element 10 according to the present embodiment and the electricity storage element according to the comparative example is tightened with a stainless steel plate having a thickness of 5 mm, and thereby a surface pressure of 1.5 kgf / cm ² is applied thereto. Was applied. Then, the vibration test was implemented in the state which applied the said surface pressure.

  As a result of this evaluation test, in the electricity storage device according to the comparative example, AC (alternating current) impedance was remarkably increased, and damage such as breakage of the positive electrode current collector was confirmed. On the other hand, in the electricity storage device 10 according to the present embodiment, there was little variation in AC impedance, and damage such as fracture of the positive electrode current collector 120 was not confirmed.

  Thus, it was confirmed by an evaluation test that damage to the positive electrode current collector 120 can be suppressed by disposing at least a part of the positive electrode current collector 120 at the end portion 144a.

  Further, as described above, the positive electrode current collector 120 is connected to the end portion 141 of the electrode body 140 at the connection portion 122 disposed toward the center side of the flat portion 144 in the winding direction. At the time of this connection, for example, at the end portion 141, the active material layer non-forming portion of the positive electrode body 140 is bundled for each layer and connected to the connecting portion 122, thereby In some cases, the material layer non-forming portion is gathered on the inner peripheral side. In this case, as a result, the central portions of the flat portions 143 and 144 in the winding direction may be further crushed. In addition, the factor by which the center part of the flat parts 143 and 144 is crushed is not restricted above, For example, you may be the bias of the deformation resistance of the electrode body 140 mentioned above.

  FIG. 7 is a bottom view showing the shapes of the positive electrode current collector 120 and the electrode body 140 when the central portions of the flat portions 143 and 144 in the winding direction of the electrode body 140 are further crushed in the present embodiment.

  As shown in the figure, the electrode body 140 has a shape in which the central portions of the flat portions 143 and 144 in the winding direction are deformed inward and crushed. That is, the electrode body 140 has a shape in which the central portions of the flat portions 143 and 144 are deformed toward the winding axis.

  At this time, the portion of the positive electrode current collector 120 disposed toward the center side of the flat portions 143 and 144 in the winding direction (in the present embodiment, the connection portion 122) is similarly deformed inward.

  On the other hand, due to this influence, portions of the positive electrode current collector 120 disposed at the end portions 143a, 143b, 144a, and 144b of the flat portions 143 and 144 (in this embodiment, the extending portion 121) are outside (electrode body). Deforms and swells in the direction opposite to the winding axis 140 of 140. That is, in the present embodiment, the extending portion 121 floats outside the connecting portion 122. Specifically, as shown in FIG. 7, the positive electrode current collector 120 floats outside the central portion of the flat portion 144 by a thickness D <b> 1 at the boundary between the curved portion 145 and the flat portion 144.

  Thus, when the electrode body 140 has a shape that is further crushed at the center of the flat portions 143 and 144, the positive electrode current collector 120 is disposed at the end portion 144a as viewed from the direction of the winding axis of the electrode body 140. Incline so that it protrudes outward (lifts).

  As described above, according to the electricity storage device 10 according to the present exemplary embodiment, the positive electrode current collector 120 includes only a part of the flat portions 143 and 144 in the flat portions 143 and 144 (in the present exemplary embodiment, the flat portion 144). And at least a part of the covered portion covers the end portions 143a, 143b, 144a, and 144b of the flat portions 143 and 144 in the winding direction of the electrode body 140 (in this embodiment, the flat portions). 144 at the end 144a).

  Here, as described above, the wound electrode body 140 is unlikely to be deformed at the end portions 143a, 143b, 144a, and 144b. Therefore, the end portions 143a, 143b, 144a, and 144b are particularly strongly pressed by the inner wall of the exterior body 100, and therefore, the end portions 143a, 143b, 144a, and 144b are difficult to move with respect to the exterior body 100 even in an environment where the power storage element 10 vibrates. Therefore, by disposing the positive electrode current collector 120 at the end portions 143a, 143b, 144a, and 144b (in this embodiment, the end portion 144a of the flat portion 144), the positive electrode current collector 120 can be provided even in the above environment. Such physical load can be reduced. Therefore, damage to the positive electrode current collector 120 can be suppressed.

  Moreover, according to the electrical storage element 10 which concerns on this Embodiment, the physical load concerning the positive electrode collector 120 can be reduced by providing the positive electrode collector 120 arrange | positioned as mentioned above. Therefore, damage to the positive electrode current collector 120 can be suppressed.

  Further, according to power storage device 10 according to the present exemplary embodiment, at least a part of positive electrode current collector 120 (in this exemplary embodiment, extending portion 121) includes flat portions 143 and 144 of electrode body 140 and curved portion 145. And 146 (in the present embodiment, the boundary between the flat portion 144 and the curved portion 145).

  Here, as described above, in the wound electrode body 140, the boundaries between the flat portions 143 and 144 and the curved portions 145 and 146 are particularly difficult to deform. Therefore, when such an electrode body 140 is accommodated in the exterior body 100 so as to contact the inner wall of the exterior body 100, the boundary is firmly fixed to the exterior body 100. That is, the boundary is a portion where the electrode body 140 is particularly difficult to move with respect to the exterior body 100. Therefore, by disposing at least a part of the positive electrode current collector 120 (in this embodiment, the extending portion 121) at the boundary, damage to the positive electrode current collector 120 can be further suppressed.

  Moreover, according to the electrical storage element 10 according to the present embodiment, the positive electrode current collector 120 is a portion (in this embodiment, a connecting portion) that is disposed toward the center side of the flat portions 143 and 144 in the winding direction. 122), when the central portions of the flat portions 143 and 144 are further crushed, the portions disposed at the end portions 143a, 143b, 144a, and 144b (the end portion 144a in this embodiment) protrude outward. Tilt to do (raise). Therefore, when the electrode body 140 is accommodated so as to be in contact with the inner wall of the exterior body 100, the positive electrode current collector 120 is disposed between the ends 143 a, 143 b, 144 a, and 144 b and the inner wall of the exterior body 100. The frictional force increases. That is, since the positive electrode current collector 120 becomes more difficult to move with respect to the exterior body 100, damage to the positive electrode current collector 120 can be further suppressed.

  Further, according to the present embodiment, the positive electrode current collector 120 has the extending portion 121 extending in a direction parallel to the winding axis of the electrode body 140, so that the positive electrode current collector 120 and the inner wall of the electrode body 140 Since the positive electrode current collector 120 can be sandwiched with a larger area, damage to the positive electrode current collector 120 can be further suppressed.

  In particular, in the present embodiment, the extending portion 121 is disposed at the end portion 144a. Thereby, since the area of the positive electrode collector 120 arrange | positioned in the part which the electrode body 140 cannot move easily with respect to the exterior body 100 can be ensured, damage to the positive electrode collector 120 can be suppressed further.

(Modification 1)
Next, Modification 1 of the present embodiment will be described. In the above embodiment, the positive electrode current collector 120 has one elongated extending portion 121 extending in a direction (Z-axis direction) parallel to the winding axis of the electrode body 140. On the other hand, in this modification, the positive electrode current collector has a plurality of extending portions each covering only one part of the pair of flat portions 144 of the electrode body 140.

  FIG. 8 is a side view showing the shapes of positive electrode current collector 120A and electrode body 140 according to Modification 1 of the embodiment of the present invention. In addition, the same figure is a side view which shows the structure in the state which isolate | separated the main body 111 of the exterior body 100 from the electrical storage element. 9 is a cross-sectional view taken along the line IX-IX in FIG.

  As shown in these drawings, in the present modification, the positive electrode current collector 120A is disposed at the extending portion 121a disposed at one end portion 144a of the flat portion 144 in the winding direction and at the other end portion 144b. Extending portion 121b. Furthermore, in this modification, the positive electrode current collector 120A includes a connecting portion 123 that connects the extending portion 121a and the extending portion 121b.

  Since the extending portion 121a corresponds to the extending portion 121 in the above embodiment, the description is omitted.

  The extending portion 121b has a long shape extending in a direction parallel to the winding axis of the electrode body 140, similarly to the extending portion 121a. However, the extending portion 121b is arranged at the end portion 144b, unlike the extending portion 121a. Specifically, the extending portion 121 b extends from one end of the connecting portion 123 to the end portion 141 on the positive electrode side of the electrode body 140.

  The connection part 123 is arrange | positioned at the edge part 142 by the side of the negative electrode which is an edge part of the electrode body 140 in the direction of the winding axis of the electrode body 140, and is arrange | positioned so that the extending part 121a and the extending part 121b may be connected.

  Further, the extending portion 121a and the extending portion 121b are connected to each other also by a portion (a portion excluding the bellows portion) of the connecting portion 122 formed in a flat plate shape.

  Thereby, the end 142 in the direction of the winding axis of the electrode body 140 can be protected. For example, since the active material layer of the negative electrode is not formed at the end portion 142, the strength may decrease due to the thickness being thinner than the central portion of the electrode body 140. Therefore, since the end portion 142 can be protected by arranging the connecting portion 123 at the end portion 142, problems such as damage in a portion where the strength of the electrode body 140 is likely to be reduced can be suppressed.

  Even the power storage device according to this modification configured as described above can achieve the same effects as those of the above-described embodiment. That is, as described in the above embodiment, the end portions 143a, 143b, 144a, and 144b that are particularly strongly pressed by the inner wall of the exterior body 100 of the power storage element (in this modification, the end portions 144a and 144b of the flat portion 144 are used). ) To prevent the positive electrode current collector 120A from being damaged.

  In the present modification, the positive electrode current collector 120A can be more firmly fixed by having the plurality of extending portions (in the present modification, two extending portions 121a and 121b) in the positive electrode current collector 120A. Compared to the above-described embodiment having only one extending portion 121, for example, the physical load applied to each extending portion 121a and 121b can be reduced in an environment where the power storage element vibrates. Therefore, damage to the positive electrode current collector 120A can be more reliably suppressed.

  In this modification, a plurality of extending portions (two extending portions 121a and 121b in the present modified example) are part of the same flat portion (flat portion 144 in the present modified example) of the pair of flat portions 143 and 144. It is arranged to cover only.

  Thereby, compared with the case where a plurality of extending portions (two extending portions 121a and 121b in this modification) are arranged in different flat portions 143 and 144, the positive electrode current collector 120A and the exterior 140 The body 100 can be sandwiched and fixed in a well-balanced manner. Therefore, since the positive electrode current collector 120A can be stably fixed, damage to the positive electrode current collector 120A can be more reliably suppressed.

(Modification 2)
Next, a second modification of the present embodiment will be described. In Modification 1 of the above-described embodiment, a plurality of extending portions (two extending portions 121a and 121b in Modification 1) are arranged in the same flat portion (flat portion 144 in Modification 1). On the other hand, in the present modification, the plurality of extending portions are arranged in different flat portions.

  FIG. 10 is a perspective view showing components arranged inside exterior body 100 of the energy storage device according to Modification 2 of the embodiment of the present invention. Specifically, FIG. 10 is a perspective view illustrating a configuration in a state where the main body 111 of the outer package 100 is separated from the power storage element. 11 is a cross-sectional view taken along the line XI-XI in FIG.

  As shown in these drawings, in this modification, the positive electrode current collector 120B includes an extending portion 121c disposed at one end portion 144a of the flat portion 144 in the winding direction, and a flat portion 143 in the winding direction. Extension portion 121d disposed at one end portion 143a.

  Since the extending portion 121c corresponds to the extending portion 121a in the first modification of the above embodiment, the description thereof is omitted.

  The extending part 121d has a long shape extending in a direction (Z-axis direction) parallel to the winding axis of the electrode body 140, similarly to the extending part 121c. However, unlike the extending portion 121c, the extending portion 121d is disposed at the end portion 143a of the flat portion 143. Specifically, the extending portion 121 d extends from the positive electrode terminal 200 side to the positive electrode-side end portion 141 of the electrode body 140.

  The extending portion 121c and the extending portion 121d are connected to each other by the bellows portion of the connecting portion 122.

  Even the power storage device according to this modification configured as described above can achieve the same effects as those of the above-described embodiment. In other words, as described in the above embodiment, the positive electrodes are collected at the end portions 143a, 143b, 144a, and 144b (in the present modification, the end portions 143a and 144a) that are particularly strongly pressed by the inner wall of the exterior body 100 of the storage element. By disposing the electric body 120B, damage to the positive electrode current collector 120B can be suppressed.

  Further, in the present modification, as in Modification 1 of the above embodiment, the positive electrode current collector 120B has a plurality of extending portions 121c and 121d, so that damage to the positive electrode current collector 120B can be more reliably suppressed. Can do.

(Modification 3)
Next, a third modification of the present embodiment will be described. In the above-described embodiment and the modifications 1 and 2, the extending portion is disposed at at least one of the end portions 143a, 143b, 144a, and 144b. On the other hand, in this modification, the extending portion is disposed at the center of the flat portions 143 and 144 in the winding direction, and protrudes from the extending portion toward at least one of the end portions 143a, 143b, 144a, and 144b. A protrusion is disposed.

  FIG. 12 is a side view showing shapes of positive electrode current collector 120C and electrode body 140 according to Modification 3 of the embodiment of the present invention. In addition, the same figure is a side view which shows the structure in the state which isolate | separated the main body 111 of the exterior body 100 from the electrical storage element.

  As shown in the figure, the positive electrode current collector 120C according to this modification example is different from the positive electrode current collector 120 according to the embodiment in place of the extending portion 121 and in the central portion of the flat portion 144 in the winding direction. The point which has the extending part 121e arrange | positioned in this, and also has the protrusion part 121f which protrudes from the said extending part 121e differs. In addition, since the extending part 121e has the same configuration as the extending part 121 except for the arrangement position, the details are omitted.

  The protruding portion 121f protrudes from the extending portion 121e toward the end portion 144a of the flat portion 144 at the central portion of the extending portion 121e in the direction parallel to the winding axis of the electrode body 140 (Z-axis direction in the figure). Has been placed. That is, the protrusion 121f is disposed at the end 144a (see FIG. 3B and the like).

  The power storage device according to this modification configured as described above has a smaller contact area between positive electrode current collector 120C and end portion 144a than the power storage device according to the embodiment. Although somewhat inferior, the same effect as the above embodiment can be obtained. In other words, as described in the above embodiment, the positive electrode current collector is attached to the end portions 143a, 143b, 144a, and 144b (in this modification, the end portion 144a) that are particularly strongly pressed by the inner wall of the exterior body 100 of the power storage element. By disposing 120C, damage to the positive electrode current collector 120C can be suppressed.

  The protruding portion 121f may protrude at the end of the extending portion 121e in the direction parallel to the winding axis of the electrode body 140.

(Modification 4)
Next, Modification 4 of the present embodiment will be described. In the said embodiment and its modifications 1-3, the exterior body 100 was taken as the bottomed elliptical cylinder. That is, when viewed from above (viewed from the plus side in the Z-axis direction), the exterior body 100 has a shape along the outer shape of the electrode body 140. On the other hand, in this modification, the exterior body has a bottomed rectangular shape (box shape).

  FIG. 13 is a perspective view schematically showing an external appearance of a power storage element 10D according to Modification 4 of the embodiment of the present invention.

  As shown in the figure, a power storage element 10D according to the present modification is different from the power storage element 10 according to the embodiment in that a bottomed rectangular-shaped exterior body 100 is used instead of a bottomed long cylindrical exterior body 100. A body 100D is provided.

  The exterior body 100D includes a main body 111D having a rectangular shape and a bottom, and a lid body 110D that is a plate-like member that closes the opening of the main body 111D. The exterior body 100D has the same configuration as that of the exterior body 100 except that the exterior body 100D is formed in a rectangular shape.

  Even the power storage device 10D according to the present modification configured as described above can achieve the same effects as those of the above-described embodiment.

(Other variations)
The power storage device according to the embodiment of the present invention and the modification thereof has been described above, but the present invention is not limited to this embodiment and the modification thereof.

  In other words, it should be considered that the embodiment and its modification disclosed this time are illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, the electrode body 140 has a positive electrode-side end portion 141 in which a positive electrode active material layer non-forming portion is laminated at an end portion on the positive side in the Z-axis direction and an active portion of the negative electrode at an end portion on the negative side in the Z-axis direction. It may have an end 142 on the negative electrode side where the material layer non-formation part is laminated.

  Further, the positive electrode current collector described in the above embodiment and its modifications is included in the “spacer” described in the claims. However, the “spacer” described in the claims may be a member arranged as described above, for example, to improve insulation between the electrode body 140 and another conductive member, or An insulating member that can be secured may be used. The member may be a negative electrode current collector. That is, the “spacer” described in the claims includes a current collector such as a positive electrode current collector or a negative electrode current collector, or a so-called spacer such as an insulating member.

  Further, the electrode body 140 may be of a winding type, and may have an elliptical shape when viewed from the winding axis direction. That is, the pair of opposed flat portions may not be flat, and may be curved surfaces. In other words, when viewed from the winding axis direction, each of the pair of flat portions does not have to be linear and may be curved.

  Further, the winding axis of the electrode body 140 may be in the horizontal direction (direction parallel to the XY plane).

  Further, the shape of the positive electrode current collector covers only a part of the flat parts 143 and 144 in the flat parts 143 and 144, and at least a part of the covered part is arranged at the end parts 143a, 143b, 144a and 144b. Any shape can be used. For example, the positive electrode current collector may not be disposed at the boundary between the flat portions 143 and 144 and the curved portions 145 and 146 of the electrode body 140.

  Further, the positive electrode current collector does not have a portion arranged toward the center side of the flat portions 143 and 144 in the winding direction, and is arranged to extend in a direction parallel to the winding axis direction of the electrode body 140. It may be. In the case of this configuration, although the frictional force generated between the positive electrode current collector and the inner wall of the exterior body 100 is somewhat reduced, it is possible to suppress damage to the positive electrode current collector as in the above-described embodiment and its modifications. Can do.

  Moreover, you may have the elongate part extended in a winding direction, without having the elongate extending part extended in the direction parallel to the winding axis | shaft of the electrode body 140, for example.

  Moreover, the part which covers only a part of the flat part 144 among positive electrode collectors is not restricted to one place, and may be a plurality of places.

  Further, the positive electrode current collector may be disposed so as to cover only a part of the flat portion 143 out of the pair of flat portions 143 and 144.

  The connecting portion 122 is connected and fixed to the electrode body 140 in a region adjacent to the curved portions 145 and 146 (region not adjacent to the flat portions 143 and 144) of the positive electrode side end portion 141 of the electrode body 140. It doesn't matter.

  Further, the number of extending portions may be any number of 1 or more. However, in general, the energy density of the power storage element increases as the mass of the current collector such as the positive electrode current collector or the negative electrode current collector decreases. Therefore, when high energy density is required, it is preferable to reduce the number of stretched portions.

  In addition, the positive electrode current collector is less likely to be damaged as the areas arranged at the end portions 143a, 143b, 144a, and 144b are larger. However, on the other hand, the increase in the size of the positive electrode current collector causes a decrease in the energy density of the power storage element. Therefore, it is preferable that the positive electrode current collector is appropriately designed according to the use required for the power storage element.

  Moreover, the form constructed | assembled combining the said embodiment and its modification arbitrarily is also contained in the scope of the present invention. Moreover, the structure which combines suitably the partial structure of the said embodiment and its modification may be sufficient. For example, the configuration of the modification 1 of the embodiment described above may be combined with the configuration of the modification 4, or the configuration of the modification 1 of the embodiment may be combined with the configuration of the modification 2. It does not matter.

  The present invention can provide a power storage element capable of suppressing damage to the spacer, and thus can be applied to a power storage element mounted on an artificial satellite or the like, for example, which requires high resistance in an environment where the power storage element vibrates.

10, 10D Storage element 100, 100D Exterior body 110, 110D Lid body 111, 111D Main body 120, 120A, 120B, 120C Positive electrode current collector 121, 121a, 121b, 121c, 121d, 121e Extending part 121f Protruding part 122 Connecting part 123 Connecting portion 130 Negative electrode current collector 140 Electrode body 141, 142, 143a, 143b, 144a, 144b End portion 143, 144 Flat portion 145, 146 Bending portion 200 Positive electrode terminal 300 Negative electrode terminal

Claims (3)

An electrical storage element comprising an electrode body formed by winding an electrode plate, an exterior body housing the electrode body, and a spacer disposed between the electrode body and the exterior body,
The electrode body has a pair of opposed flat portions and a curved portion connecting the pair of flat portions,
The spacer covers only a part of the flat part in the flat part, and at least a part of the covering part is disposed at an end part of the flat part in the winding direction of the electrode body and the electrode body An extending portion extending in a direction parallel to the winding axis of
The extending portion is disposed so as to be closer to the exterior body toward the end portion from the central portion of the flat portion in the winding direction ,
The said spacer is an electrical storage element which is a collector which connects the said electrode body and an electrode terminal . The power storage element according to claim 1, wherein at least a part of the spacer is disposed at a boundary between the flat portion and the curved portion of the electrode body. The spacer, the electric storage device according to claim 1 or 2 having a portion disposed toward the center of the flat portion in the winding direction.

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