JP2023140177A - Electrode body and power storage element - Google Patents

Abstract

To appropriately allow a connection of an electrode to a tub even if the number of electrodes is increased.SOLUTION: An electrode body 10 comprises a plurality of positive electrodes 20 and a plurality of negative electrodes 30 which are alternately overlapped to a first direction d1. The plurality of positive electrodes 20 contains: a plurality of first positive electrodes 20A; and a plurality of second positive electrodes 20B. Each first positive electrode 20A includes a first positive electrode extension part 21A extended to a second direction d2 in non-parallel to the first direction d1. Each second positive electrode 20B includes a second positive electrode extension part 21B extended to a second direction d2. The plurality of first positive electrode extension parts 21A is overlapped to the first direction d1. The plurality of second positive electrode extension parts 21B is overlapped to the first direction d1. The second positive electrode extension part 21B is deviated from the first positive electrode extension part 21A in the second direction d2 or a third direction d3 which is non-parallel to the first direction d1 and the second direction d2.SELECTED DRAWING: Figure 4

Description

The present invention relates to an electrode body and a power storage element having the electrode body.

For example, as proposed in Patent Document 1, a power storage element having an electrode body formed by alternately stacking positive electrodes and negative electrodes is known. In the electricity storage element, an electrode body is housed inside an exterior body. In order to extract power from the electrode body, the electrode body has tabs connected to each of the positive and negative electrodes. More specifically, the electrodes are connected to each other at a portion of each electrode of the electrode body, and the tab is connected to each electrode at the portion where the electrodes are connected. The electrode and the tab are electrically connected by, for example, being welded at the connection portion. Moreover, the tab extends to the outside of the exterior body. By connecting each tab to an external device that requires power, power can be supplied to the device from the power storage element.

Special table 2015-513183 publication

In order to increase the power supplied by the power storage element, increasing the number of electrodes is being considered. Increasing the number of electrodes increases the total thickness of the electrodes at the connection. If the total thickness of the electrodes becomes too thick, the electrodes may not be able to properly connect to the tabs at the connection. An object of the present invention is to enable appropriate connection of electrodes to tabs even when the number of electrodes is increased.

The electrode body of the present invention is
comprising a plurality of positive electrodes and negative electrodes stacked alternately in a first direction,
The plurality of positive electrodes include a plurality of first positive electrodes and a plurality of second positive electrodes,
The first positive electrode has a first positive electrode extension portion extending in a second direction non-parallel to the first direction,
The second positive electrode has a second positive electrode extension portion extending in the second direction,
The plurality of first positive electrode extension portions overlap in the first direction,
The plurality of second positive electrode extension portions overlap in the first direction,
The second positive electrode extending portion is offset from the first positive electrode extending portion in the second direction or a third direction non-parallel to the first direction and the second direction.

In the electrode body of the present invention, the number of positive electrodes may be 100 or more.

In the electrode body of the present invention, the first positive electrode extension portion may have a thickness of 10 μm or more.

In the electrode body of the present invention, the product of the thickness of the first positive electrode extension and the number of first positive electrodes may be 3000 μm or less.

In the electrode body of the present invention, the first positive electrode and the second positive electrode may be arranged alternately in the first direction.

In the electrode body of the present invention, in the first direction, a first laminate in which the first positive electrodes and the negative electrodes are alternately arranged, and a second laminate in which the second positive electrodes and the negative electrodes are alternately arranged. , may overlap.

The electrode body of the present invention may further include a positive electrode tab to which the plurality of first positive electrode extension parts and the plurality of second positive electrode extension parts are connected to each other at different positions.

In the electrode body of the present invention,
The plurality of negative electrodes include a plurality of first negative electrodes and a plurality of second negative electrodes,
The first negative electrode has a first negative electrode extension portion extending in the second direction,
The second negative electrode has a second negative electrode extension portion extending in the second direction,
The plurality of first negative electrode extension parts overlap in the first direction,
The plurality of second negative electrode extension portions overlap in the first direction,
The second negative electrode extending portion may be offset from the first negative electrode extending portion in the second direction or the third direction.

The electrode body of the present invention may further include a negative electrode tab to which the plurality of first negative electrode extension parts and the plurality of second negative electrode extension parts are connected to each other at different positions.

The electrode body of the present invention may further include an insulator layer disposed between the positive electrode and the negative electrode.

The electricity storage element of the present invention is
An exterior body including a first exterior material and a second exterior material;
Any one of the electrode bodies described above is provided, which is accommodated in a housing space formed between the first exterior material and the second exterior material.

According to the present invention, even if the number of electrodes is increased, the electrodes can be properly connected to the tabs.

FIG. 1 is a perspective view showing a power storage element. FIG. 2 is a plan view showing the power storage element. FIG. 3 is a plan view showing the electrode body. FIG. 4 is a cross-sectional view of the power storage element along line IV-IV in FIG. FIG. 5 is an enlarged view showing the vicinity of the tab. FIG. 6 is a cross-sectional view of a power storage element according to a modified example. FIG. 7 is a plan view of another modified example of the electrode body. FIG. 8 is a plan view of yet another modified example of the electrode body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to specific examples shown in the drawings. In the drawings attached to this specification, the scale, vertical and horizontal dimension ratios, etc. are appropriately changed and exaggerated from those of the actual drawings for ease of illustration and understanding.

As used herein, terms such as "parallel," "orthogonal," "identical," etc., and values of length and angle that specify shapes, geometric conditions, and their degrees are not strictly defined. It shall be interpreted without limitation to include the extent to which similar functions can be expected.

1 to 5 are diagrams for explaining one embodiment of a power storage element according to the present invention. FIG. 1 is a perspective view showing a specific example of a power storage element. FIG. 2 shows the power storage element 1 in plan view. In this specification, planar view refers to observing a flat or flat member from the normal direction of the sheet surface of the member. As shown in FIGS. 1 and 2, the power storage element 1 includes an exterior body 7 and an electrode body 10 accommodated in a housing space 7x formed by the exterior body 7.

The power storage element 1 is typically a secondary battery that can be charged and discharged. The power storage element 1 can be used as an emergency power source, a household power source, a vehicle-mounted power source, and the like. The power storage element 1 is, for example, a lithium ion secondary battery. However, as can be understood from the description of the effects described below, the embodiment described here is not limited to lithium ion secondary batteries. For example, power storage element 1 may be a lithium ion capacitor.

In the example shown in FIGS. 1 and 2, the electricity storage element 1 has a thin flat shape in the first direction d1, which is the thickness direction, and in the second direction d2, which is the transverse direction, and in the longitudinal direction. It spreads in the third direction d3. The first direction d1, the second direction d2 and the third direction d3 are non-parallel to each other and preferably orthogonal to each other. In this embodiment, a plan view of power storage element 1 and electrode body 10 means observation from a direction along the first direction d1.

Below, each component of the power storage element 1 will be explained regarding a specific example in which the power storage element 1 is a lithium ion secondary battery.

The electrode body 10 has an overall flat shape, is thin in the first direction d1, and spreads in the second direction d2 and the third direction d3.

FIG. 3 is a diagram of the power storage element 1 of FIG. 2 with the exterior body 7 removed. FIG. 3 shows a plan view of the electrode body 10. FIG. 4 is a cross-sectional view of power storage element 1 taken along line IV-IV in FIG. As shown in FIGS. 3 and 4, the electrode body 10 includes a plurality of positive electrodes 20, a plurality of negative electrodes 30, a positive electrode tab 12, a negative electrode tab 13, an insulator layer 15, and a sealant 18. are doing. As shown in FIG. 4, the positive electrodes 20 and the negative electrodes 30 are alternately stacked in the first direction d1. The positive electrode tab 12 is connected to the positive electrode 20. The negative electrode tab 13 is connected to the negative electrode 30. The insulator layer 15 is arranged between the positive electrode 20 and the negative electrode 30 or between the positive electrode 20 and the negative electrode 30 and the exterior body 7. The sealant 18 partially covers the positive electrode tab 12 and the negative electrode tab 13. The number of positive electrodes 20 and the number of negative electrodes 30 are each 100 or more, for example.

As shown in FIG. 4, the plurality of positive electrodes 20 include a plurality of first positive electrodes 20A and a plurality of second positive electrodes 20B. In this embodiment, the positive electrode 20 is either the first positive electrode 20A or the second positive electrode 20B. In the example shown in FIG. 4, the first positive electrodes 20A and the second positive electrodes 20B are arranged alternately in the first direction d1. The plurality of negative electrodes 30 include a plurality of first negative electrodes 30A and a plurality of second negative electrodes 30B. In this embodiment, the negative electrode 30 is either the first negative electrode 30A or the second negative electrode 30B. In the example shown in FIG. 4, the first negative electrodes 30A and the second negative electrodes 30B are arranged alternately in the first direction d1. In the first direction d1, the first positive electrode 20A, the first negative electrode 30A, the second positive electrode 20B, and the second negative electrode 30B are repeatedly lined up and overlapped in this order.

Not limited to the illustrated example, the positive electrode 20 may further include a third positive electrode different from both the first positive electrode 20A and the second positive electrode 20B, and the negative electrode 30 may further include the first negative electrode 30A and the second negative electrode. 30B may further include a third negative electrode different from any of 30B.

In a lithium ion secondary battery, the positive electrode 20 stores lithium ions during discharging and releases lithium ions during charging. As shown in FIG. 4, the positive electrode 20 includes a positive electrode current collector 20X and a positive electrode active material layer 20Y provided on the positive electrode current collector 20X. The positive electrode current collector 20X may be formed of, for example, a conductive metal such as copper, aluminum, titanium, nickel, or stainless steel, particularly aluminum foil. The positive electrode active material layer 20Y includes, for example, a metal lithium phosphate compound such as lithium iron phosphate.

In a lithium ion secondary battery, the negative electrode 30 releases lithium ions during discharging and occludes lithium ions during charging. As shown in FIG. 4, the negative electrode 30 includes a negative electrode current collector 30X and a negative electrode active material layer 30Y provided on the negative electrode current collector 30X. The negative electrode current collector 30X is made of a conductive metal such as copper, aluminum, titanium, nickel, or stainless steel, particularly copper foil. The negative electrode active material layer 30Y includes, for example, carbon powder, graphite powder, a composite of a tin compound, silicon, and carbon, lithium, and the like.

In the non-limiting example shown in FIG. 3, the positive electrode 20 and the negative electrode 30 are plate-shaped electrodes having a substantially rectangular outer contour. The second direction d2 is the lateral direction (width direction) of the positive electrode 20 and the negative electrode 30, and the third direction d3 is the longitudinal direction of the positive electrode 20 and the negative electrode 30. As shown in FIG. 3, the positive electrode 20 and the negative electrode 30 are arranged offset in the third direction d3. More specifically, the plurality of positive electrodes 20 are arranged closer to one side in the third direction d3, and the plurality of negative electrodes 30 are arranged closer to the other side in the third direction d3. The positive electrode 20 and the negative electrode 30 overlap in the first direction d1 at the center in the third direction d3.

In the central part in the third direction d3 where the positive electrode 20 and the negative electrode 30 overlap, a positive electrode active material layer 20Y is provided on the positive electrode current collector 20X, and a negative electrode active material layer 30Y is provided on the negative electrode current collector 30X. It is being

At the end of the positive electrode 20 in the third direction d3, the positive electrode active material layer 20Y is not provided on the positive electrode current collector 20X, and the positive electrode current collector 20X is exposed. FIG. 5 shows an enlarged view of the end of the positive electrode 20 in the third direction d3. As shown in FIG. 5, a portion of the positive electrode 20 extends in the second direction d2 in the exposed portion of the positive electrode current collector 20X. In other words, the positive electrode 20 has a positive electrode extension portion extending in the second direction d2. In particular, the first positive electrode 20A has a first positive electrode extension part 21A extending in the second direction d2, and the second positive electrode 20B has a second positive electrode extension part 21B extending in the second direction d2. There is. The second positive electrode extending portion 21B is offset from the first positive electrode extending portion 21A in plan view, in other words, in the second direction d2 or the third direction d3. The first positive electrode extending portion 21A and the second positive electrode extending portion 21B are provided at mutually different positions in a plan view.

The plurality of first positive electrode extension parts 21A overlap in the first direction d1. The plurality of second positive electrode extension parts 21B overlap in the first direction d1. The plurality of first positive electrode extension parts 21A and the plurality of second positive electrode extension parts 21B are each joined to each other by, for example, resistance welding, ultrasonic welding, adhesion with tape, or fusion, and are electrically connected to each other. There is. The first positive electrode extending portion 21A and the second positive electrode extending portion 21B are electrically connected to the positive electrode tab 12, respectively.

The thickness of the first positive electrode extension portion 21A is, for example, the same as the thickness of the first positive electrode 20A. The thickness of the first positive electrode extension portion 21A is 10 μm or more. The product of the thickness of the first positive electrode extending portion 21A and the number of first positive electrodes 20A, in other words, the total thickness of the plurality of joined first positive electrode extending portions 21A is 3000 μm or less, preferably 1500 μm or less, more preferably is 1300 μm or less.

Similarly, the thickness of the second positive electrode extension portion 21B is, for example, the same as the thickness of the second positive electrode 20B. The thickness of the second positive electrode extension portion 21B is 10 μm or more. The product of the thickness of the second positive electrode extending portion 21B and the number of second positive electrodes 20B, in other words, the total thickness of the plurality of joined second positive electrode extending portions 21B is 3000 μm or less, preferably 1500 μm or less, more preferably It is 1300 μm or less.

At the end of the negative electrode 30 in the third direction d3, the negative electrode active material layer 30Y is not provided on the negative electrode current collector 30X, and the negative electrode current collector 30X is exposed. Similar to the positive electrode 20 shown in FIG. 5, a portion of the negative electrode 30 extends in the second direction d2 in the exposed portion of the negative electrode current collector 30X. In other words, the negative electrode 30 has a negative electrode extension portion extending in the second direction d2. In particular, the first negative electrode 30A has a first negative electrode extension part 31A extending in the second direction d2, and the second negative electrode 30B has a second negative electrode extension part 31B extending in the second direction d2. There is. The second negative electrode extension portion 31B is offset from the first negative electrode 30A in plan view, in other words, in the second direction d2 or the third direction d3. The first negative electrode extending portion 31A and the second negative electrode extending portion 31B are provided at different positions from each other in plan view.

The thickness of the first negative electrode extension portion 31A is, for example, the same as the thickness of the first negative electrode 30A. The thickness of the first negative electrode extension portion 31A is 6 μm or more. The product of the thickness of the first negative electrode extension part 31A and the number of first negative electrodes 30A, in other words, the total thickness of the plurality of joined first negative electrode extension parts 31A is 3000 μm or less, preferably 1500 μm or less, more preferably is 1300 μm or less.

Similarly, the thickness of the second negative electrode extension portion 31B is, for example, the same as the thickness of the second negative electrode 30B. The thickness of the second negative electrode extension portion 31B is 6 μm or more. The product of the thickness of the second negative electrode extension part 31B and the number of second negative electrodes 30B, in other words, the total thickness of the plurality of joined second negative electrode extension parts 31B is 3000 μm or less, preferably 1500 μm or less, more preferably is 1300 μm or less.

The insulator layer 15 supplies electrolyte to the positive electrode 20 and negative electrode 30 while preventing short circuit between the positive electrode 20 and negative electrode 30 and short circuit between the positive electrode 20 and negative electrode 30 and the exterior body 7 . Ions are movable in the insulator layer 15 . The insulator layer 15 is a sheet-like member. The insulator layer 15 covers the positive electrode active material layer 20Y and the negative electrode active material layer 30Y in plan view.

The insulator layer 15 may be a solid electrolyte or a porous separator impregnated with an electrolyte. Materials for the solid electrolyte include, for example, polymer materials such as Li _1.5 Al _0.5 Ge _1.6 (PO ₄ ) ₃ , sulfide materials such as Li ₂ SP ₂ S ₅ , and Li ₂ O-B. It is an oxide-based material such as ₂ O _{3 and} SiO ₂ . The material of the separator is, for example, thermoplastic resin such as polypropylene. When the insulator layer 15 is a separator, an appropriate amount of electrolyte is accommodated in the accommodation space 7x.

The positive electrode tab 12 functions as a terminal of the positive electrode 20. The positive electrode tab 12 is electrically connected to all the positive electrodes 20 of the electrode body 10 at the positive electrode extension portion. The first positive electrode extending portion 21A and the second positive electrode extending portion 21B are connected to the positive electrode tab 12 at mutually different positions. In other words, the positive electrode 20 is divided into two parts, the first positive electrode 20A and the second positive electrode 20B, which are connected at the positive electrode tab 12. The positive electrode tab 12 extends outside the exterior body 7 in the second direction d2 and/or the third direction d3. In the illustrated example, the positive electrode tab 12 extends outside the exterior body 7 in the third direction d3.

The negative electrode tab 13 functions as a terminal of the negative electrode 30. The negative electrode tab 13 is electrically connected to all the negative electrodes 30 included in the electrode body 10 at the negative electrode extension portion. The first negative electrode extension part 31A and the second negative electrode extension part 31B are connected to the negative electrode tab 13 at mutually different positions. In other words, the negative electrode 30 is divided into two parts, the first negative electrode 30A and the second negative electrode 30B, which are connected at the negative electrode tab 13. The negative electrode tab 13 extends outside the exterior body 7 in the second direction d2 and/or the third direction d3. The negative electrode tab 13 may extend from the same side in the same direction as the positive electrode tab 12, or may extend in a different direction. In the illustrated example, the negative electrode tab 13 extends outside the exterior body 7 from a side different from the positive electrode tab 12 in the same third direction d3 as the positive electrode tab 12.

The positive electrode tab 12 and the negative electrode tab 13 are plate-shaped conductors. The thickness of the positive electrode tab 12 and the negative electrode tab 13 is, for example, 0.1 mm or more and 1 mm or less. The material of the positive electrode tab 12 and the negative electrode tab 13 is, for example, aluminum, nickel, or nickel-plated copper. The positive electrode tab 12 and the negative electrode tab 13 may be made of the same material and structure, or may be made of at least one different material and structure.

The sealant 18 seals between the positive electrode tab 12 and the negative electrode tab 13 and the exterior body 7. The sealant 18 circumferentially surrounds a portion of the positive electrode tab 12 and a portion of the negative electrode tab 13, respectively. The sealant 18 has adhesive properties and joins the positive electrode tab 12 and the negative electrode tab 13 to the exterior body 7. The sealant 18 prevents electrical connection between the positive electrode tab 12 and the negative electrode tab 13 and the exterior body 7. The material of the sealant 18 is, for example, polypropylene, modified polypropylene, low density polyethylene, ionomer, or ethylene/vinyl acetate copolymer.

The exterior body 7 is a package for the electrode body 10. As shown in FIG. 4, the exterior body 7 forms a housing space 7x for housing the electrode body 10. The exterior body 7 accommodates and seals the electrode body 10 excluding a portion of the positive electrode tab 12 and a portion of the negative electrode tab 13 in the housing space 7x.

As shown in FIG. 4, the exterior body 7 includes a first exterior material 7a and a second exterior material 7b. The positive electrode tab 12 and the negative electrode tab 13 pass between the first exterior material 7a and the second exterior material 7b, and extend to the outside of the exterior body 7.

The first exterior material 7a and the second exterior material 7b are sheet-like members. The first exterior material 7a and the second exterior material 7b become the exterior body 7 by, for example, welding their peripheral edges 7c. The first exterior material 7a includes a bulge 7d. The second exterior material 7b does not include a bulge and is flat. The second exterior material 7b may also include a bulge, not limited to the illustrated example. The bulging portion 7d is formed, for example, by drawing. A housing space 7x for the exterior body 7 is formed by the bulging portion 7d.

An example of a method for manufacturing the above-described power storage element 1 and electrode body 10 will be described.

The positive electrode 20 is produced by applying the material of the positive electrode active material layer 20Y onto the positive electrode current collector 20X and drying it. The negative electrode 30 is produced by applying the material of the negative electrode active material layer 30Y onto the negative electrode current collector 30X and drying it. Of the positive electrodes 20, the first positive electrode 20A is provided with a first positive electrode extending portion 21A, and the second positive electrode 20B is provided with a second positive electrode extending portion 21B. Of the negative electrodes 30, the first negative electrode 30A is provided with a first negative electrode extending portion 31A, and the second negative electrode 30B is provided with a second negative electrode extending portion 31B.

The positive electrode 20, the insulating layer 15, the negative electrode 30, and the insulating layer 15 are repeatedly stacked in this order. For example, when manufacturing the electrode body 10 of the example shown in FIG. 30B, the insulating layer 15 is repeatedly stacked in this order. Positive electrodes 20 and negative electrodes 30 are stacked alternately, and an insulator layer 15 is disposed between positive electrodes 20 and negative electrodes 30. The number of positive electrodes 20 and the number of negative electrodes 30 are each 100 or more.

The first positive electrode extending portion 21A, the second positive electrode extending portion 21B, the first negative electrode extending portion 31A, and the second negative electrode extending portion 31B overlap in the first direction d1 at different positions in a plan view.

The positive electrode tab 12 is connected to the first positive electrode extending portion 21A and the second positive electrode extending portion 21B. The first positive electrode extending portion 21A and the second positive electrode extending portion 21B are welded to the positive electrode tab 12 at different positions, for example, by ultrasonic bonding. Similarly, the negative electrode tab 13 is connected to the first negative electrode extension part 31A and the second negative electrode extension part 31B. The first negative electrode extension part 31A and the second negative electrode extension part 31B are welded to the negative electrode tab 13 at different positions, for example, by ultrasonic bonding.

Through the above steps, the electrode body 10 is manufactured.

A first exterior material 7a and a second exterior material 7b are prepared. A bulging portion 7d is formed in the first exterior material 7a by, for example, embossing.

The electrode body 10 is arranged between the first exterior material 7a and the second exterior material 7b. The positive electrode tab 12 and the negative electrode tab 13 extend outward from between the first exterior material 7a and the second exterior material 7b. The first exterior material 7a and the second exterior material 7b are joined at their peripheral edges 7c. The first exterior material 7a and the second exterior material 7b are joined to form the exterior body 7. The electrode body 10 is housed in the housing space 7x of the exterior body 7.

Through the above steps, power storage element 1 is manufactured.

In order to increase the power that a power storage element can supply, increasing the number of electrodes is being considered. Increasing the number of electrodes increases the total electrode thickness. The electrode is connected to the tab by being welded to the tab by, for example, ultrasonic bonding. If the total electrode thickness increases, welding may not be successful and the electrode may not connect properly to the tab. To address this issue, consideration was given to making the electrodes thinner. However, manufacturing and handling thin electrodes is costly. Furthermore, it is difficult to manufacture electrodes that are thin enough for effective welding relative to the number of electrodes.

In the electrode body 10 of this embodiment, the positive electrode 20 includes a first positive electrode 20A and a second positive electrode 20B. The second positive electrode extending portion 21B of the second positive electrode 20B is offset from the first positive electrode extending portion 21A of the first positive electrode 20A in the second direction d2 or the third direction d3. The first positive electrode 20A can be connected to the positive electrode tab 12 at the first positive electrode extension part 21A, and the second positive electrode 20B can be connected to the positive electrode tab 12 at the second positive electrode extension part 21B. The positive electrode 20 is divided into two parts, a first positive electrode 20A and a second positive electrode 20B, which are connected at the positive electrode tab 12. The number of first positive electrodes 20A connected to the positive electrode tabs 12 in the first positive electrode extension portion 21A is smaller than the total number of positive electrodes 20. Typically, the number of first positive electrodes 20A is half the number of positive electrodes 20 as a whole. The total thickness of the portion where the positive electrode 20 is connected to the positive electrode tab 12 is reduced. Even if the number of positive electrodes 20 is increased, the first positive electrode 20A can be appropriately connected to the positive electrode tab 12 at this portion. Similarly, even if the number of positive electrodes 20 is increased, the second positive electrode 20B can be appropriately connected to the positive electrode tab 12. Even if the number of positive electrodes 20 is increased, all the positive electrodes 20 can be properly connected to the positive electrode tab 12.

The negative electrode 30 includes a first negative electrode 30A and a second negative electrode 30B. The second negative electrode extending portion 31B of the second negative electrode 30B is offset from the first negative electrode extending portion 31A of the first negative electrode 30A in the second direction d2 or the third direction d3. The first negative electrode 30A can be connected to the negative electrode tab 13 at the first negative electrode extension part 31A, and the second negative electrode 30B can be connected to the negative electrode tab 13 at the second negative electrode extension part 31B. The negative electrode 30 is divided into two parts, a first negative electrode 30A and a second negative electrode 30B, and connected at the negative electrode tab 13. The number of first negative electrodes 30A connected to the negative electrode tabs 13 in the first negative electrode extension portion 31A is smaller than the total number of negative electrodes 30. Typically, the number of first negative electrodes 30A is half the number of negative electrodes 30 as a whole. The total thickness of the portion where the negative electrode 30 is connected to the negative electrode tab 13 is reduced. Even if the number of negative electrodes 30 is increased, the first negative electrode 30A can be appropriately connected to the negative electrode tab 13 at this portion. Similarly, even if the number of negative electrodes 30 is increased, the second negative electrode 30B can be appropriately connected to the negative electrode tab 13. Even if the number of negative electrodes 30 is increased, all the negative electrodes 30 can be properly connected to the negative electrode tab 13.

The number of positive electrodes 20 is 100 or more. The thickness of the first positive electrode extension portion 21A is 10 μm or more. It is difficult to weld such a positive electrode 20 to the positive electrode tab 12 without dividing it into two parts. The electrode body 10 having such a positive electrode 20 can significantly exhibit the effect that all the positive electrodes 20 can be appropriately connected to the positive electrode tab 12.

The number of negative electrodes 30 is 100 or more. The thickness of the first negative electrode extension portion 31A is 6 μm or more. It is difficult to weld such a negative electrode 30 to the negative electrode tab 13 without dividing it into two parts. The electrode body 10 having such a negative electrode 30 can significantly exhibit the effect that all the negative electrodes 30 can be appropriately connected to the negative electrode tab 13.

The product of the thickness of the first positive electrode extension portion 21A and the number of first positive electrodes 20A is 3000 μm or less, preferably 1500 μm or less, and more preferably 1300 μm or less. Since the total thickness of the first positive electrode extension portion 21A welded to the positive electrode tab 12 is not too thick, all the first positive electrodes 20A can be appropriately connected to the positive electrode tab 12.

Similarly, the product of the thickness of the second positive electrode extension portion 21B and the number of second positive electrodes 20B is 3000 μm or less, preferably 1500 μm or less, and more preferably 1300 μm or less. Since the total thickness of the second positive electrode extension portions 21B welded to the positive electrode tab 12 is not too thick, all the second positive electrodes 20B can be appropriately connected to the positive electrode tab 12.

The product of the thickness of the first negative electrode extension portion 31A and the number of first negative electrodes 30A is 3000 μm or less, preferably 1500 μm or less, and more preferably 1300 μm or less. Since the total thickness of the first negative electrode extension portion 31A welded to the negative electrode tab 13 is not too thick, all the first negative electrodes 30A can be appropriately connected to the negative electrode tab 13.

Similarly, the product of the thickness of the second negative electrode extension portion 31B and the number of second negative electrodes 30B is 3000 μm or less, preferably 1500 μm or less, and more preferably 1300 μm or less. Since the total thickness of the second negative electrode extension portions 31B welded to the negative electrode tab 13 is not too thick, all the second negative electrodes 30B can be appropriately connected to the negative electrode tab 13.

As described above, the electrode body 10 of the present embodiment includes a plurality of positive electrodes 20 and a negative electrode 30 stacked alternately in the first direction d1, and the plurality of positive electrodes 20 includes a plurality of first positive electrodes 20A and a plurality of negative electrodes 20A and 30A. , the first positive electrode 20A has a first positive electrode extension portion 21A extending in a second direction d2 non-parallel to the first direction d1, and the second positive electrode 20B has a second positive electrode extending portion 21A extending in a second direction d2 non-parallel to the first direction d1. d2, the plurality of first positive electrode extension parts 21A overlap in the first direction d1, and the plurality of second positive electrode extension parts 21B overlap in the first direction d1. The second positive electrode extending portion 21B is offset from the first positive electrode extending portion 21A in the second direction d2 or in the third direction d3 that is non-parallel to the first direction d1 and the second direction d2. According to such an electrode body 10, the total thickness of the portion where the positive electrode 20 is connected to the positive electrode tab 12 is reduced. Even if the number of positive electrodes 20 is increased, the first positive electrode 20A can be appropriately connected to the positive electrode tab 12 at this portion. Similarly, even if the number of positive electrodes 20 is increased, the second positive electrode 20B can be appropriately connected to the positive electrode tab 12. Even if the number of positive electrodes 20 is increased, all the positive electrodes 20 can be properly connected to the positive electrode tab 12.

Although one embodiment has been described using a plurality of specific examples, these specific examples are not intended to limit the one embodiment. The embodiment described above can be implemented in various other specific examples, and various omissions, substitutions, changes, additions, etc. can be made without departing from the gist thereof.

Hereinafter, modifications of the above-described embodiment will be described with reference to the drawings. In the following explanation and the drawings used in the following explanation, the same reference numerals as those used for corresponding parts in the above specific example are used for parts that may be configured in the same way as in the above specific example, and redundant explanations are used. omitted.

FIG. 6 is a cross-sectional view of the power storage element 1 corresponding to FIG. 4, and shows a modified example of the electrode body 10 included in the power storage element 1. In a modification shown in FIG. 6, the arrangement of the positive electrode 20 and the negative electrode 30 is different from the embodiment described above. In this modification, the electrode body 10 includes a first laminate 10A and a second laminate 10B. In the first stacked body 10A, the first positive electrodes 20A and the negative electrodes 30 are arranged alternately in the first direction d1. In the second stacked body 10B, the second positive electrodes 20B and the negative electrodes 30 are arranged alternately in the first direction d1. The first laminate 10A and the second laminate 10B overlap in the first direction d1. More specifically, in the first direction d1, in the first stacked body 10A, the first positive electrodes 20A and the first negative electrodes 30A are arranged alternately, and in the second stacked body 10B, the second positive electrodes 20B and the second negative electrodes 30B are arranged alternately. are arranged alternately.

7 and 8 are plan views of the electrode body 10 corresponding to FIG. 3, each showing a different modification of the electrode body 10. In the modification shown in FIGS. 7 and 8, the direction in which the positive electrode tab 12 and the negative electrode tab 13 extend is different from that of the above-described embodiment. In the example shown in FIG. 7, the positive electrode tab 12 extends in the second direction d2. The negative electrode tab 13 extends from a side different from the positive electrode tab 12 in the second direction d2. In the example shown in FIG. 8, the positive electrode tab 12 extends in the second direction d2. The negative electrode tab 13 extends from the same side as the positive electrode tab 12 in the second direction d2. The positive electrode tab 12 and the negative electrode tab 13 may extend in any manner other than the illustrated example.

1 Energy storage element 7 Exterior body 7a First exterior material 7b Second exterior material 7x Housing space 10 Electrode body 10A First laminate 10B Second laminate 12 Positive electrode tab 13 Negative electrode tab 15 Insulator layer 18 Sealant 20 Positive electrode 20A First positive electrode 20B Second positive electrode 21A First positive electrode extension 21B Second positive electrode extension 30 Negative electrode 30A First negative electrode 30B Second negative electrode 31A First negative electrode extension 31B Second negative electrode extension

Claims (11)

comprising a plurality of positive electrodes and negative electrodes stacked alternately in a first direction,
The plurality of positive electrodes include a plurality of first positive electrodes and a plurality of second positive electrodes,
The first positive electrode has a first positive electrode extension portion extending in a second direction non-parallel to the first direction,
The second positive electrode has a second positive electrode extension portion extending in the second direction,
The plurality of first positive electrode extension portions overlap in the first direction,
The plurality of second positive electrode extension portions overlap in the first direction,
The second positive electrode extending portion is offset from the first positive electrode extending portion in the second direction or in a third direction non-parallel to the first direction and the second direction. The electrode body according to claim 1, wherein the number of positive electrodes is 100 or more. The electrode body according to claim 1 or 2, wherein the first positive electrode extension has a thickness of 10 μm or more. The electrode body according to any one of claims 1 to 3, wherein the product of the thickness of the first positive electrode extension and the number of first positive electrodes is 3000 μm or less. The electrode body according to any one of claims 1 to 4, wherein the first positive electrode and the second positive electrode are arranged alternately in the first direction. In the first direction, a first laminate in which the first positive electrodes and the negative electrodes are alternately arranged and a second laminate in which the second positive electrodes and the negative electrodes are alternately arranged are overlapped. The electrode body according to any one of Items 1 to 4. The electrode body according to any one of claims 1 to 6, further comprising a positive electrode tab that connects the plurality of first positive electrode extension parts and the plurality of second positive electrode extension parts at different positions. The plurality of negative electrodes include a plurality of first negative electrodes and a plurality of second negative electrodes,
The first negative electrode has a first negative electrode extension portion extending in the second direction,
The second negative electrode has a second negative electrode extension portion extending in the second direction,
The plurality of first negative electrode extension parts overlap in the first direction,
The plurality of second negative electrode extension portions overlap in the first direction,
The electrode body according to any one of claims 1 to 7, wherein the second negative electrode extending portion is offset from the first negative electrode extending portion in the second direction or the third direction. The electrode body according to claim 8, further comprising a negative electrode tab that connects the plurality of first negative electrode extension parts and the plurality of second negative electrode extension parts at different positions. The electrode body according to any one of claims 1 to 8, further comprising an insulator layer disposed between the positive electrode and the negative electrode. An exterior body including a first exterior material and a second exterior material;
An electricity storage element, comprising: the electrode body according to any one of claims 1 to 10, which is housed in a housing space formed between the first exterior material and the second exterior material.

Images