KR102494074B1 - Energy storage device - Google Patents

Abstract

[Problem] To provide a power storage element provided with a highly reliable current collector.
[Solution] The positive terminal 200, the first electrode body 161 and the second electrode body 162, the positive terminal 200, the first electrode body 161 and the second electrode body 162 are A power storage element 10 having a positive electrode current collector 140 electrically connected to the power storage element 10, wherein the positive electrode current collector 140 includes a terminal connection portion 141 electrically connected to the positive electrode terminal 200, and a first electrode body ( 161) and the second electrode body 162, the inner electrode body connection portions 144 and 145 and the terminal connection portion 141 are extended from the ends of the terminal connection portion 141 and the inner electrode body connection portion 144 and 145 ), and the connection portion 148 has a width at a connection portion with an end of the terminal connection portion 141 and a width at a connection portion with the inner electrode body connection portions 144 and 145. It is formed so that it may become a broader trapezoidal shape.

Description

Electric storage device {ENERGY STORAGE DEVICE}

The present invention relates to a power storage element including an electrode terminal, an electrode body, and a current collector electrically connecting the electrode terminal and the electrode body.

As a response to global environmental problems, the transition from gasoline vehicles to electric vehicles is becoming important. Therefore, development of electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and the like using a power storage element such as a lithium ion secondary battery as a power source is progressing. In general, such an electricity storage element includes an electrode body having an anode and a cathode, an electrode terminal, and a current collector electrically connecting the electrode body and the electrode terminal.

Here, conventionally, a power storage element having an electrode body, bonding the electrode body to a current collector, and holding the electrode body by being suspended from the current collector has been proposed (see Patent Document 1, for example). In this power storage element, each of a plurality of legs suspended from one current collector is joined to each of a plurality of electrode bodies, and each electrode body is suspended from the current collector to hold each electrode body.

Japanese Unexamined Patent Publication No. 2013-077546

Current collectors included in power storage elements, including those described in Patent Document 1, are generally manufactured by performing processing such as bending on a metal plate material having a predetermined shape.

That is, the current collector is a member obtained by metal processing, and it is necessary to prevent cracking or bursting of the plate material during processing such as bending the plate material. For example, a notch called a nusumi (relief) is provided at the end of the bending line to relieve stress concentration that causes cracking or the like.

Due to the notch being provided at the bending position in this way, when there is a portion with a smaller cross-sectional area than the front and rear portions at the bending position, the reliability of the current collector is deteriorated, such as an increase in electrical resistance and a decrease in strength. There is a possibility that the idea of doing so will occur.

In view of the above conventional problems, an object of the present invention is to provide a power storage element having a highly reliable current collector.

To achieve the above object, a power storage element according to one aspect of the present invention provides an electrode terminal, at least one electrode body, and a current collector electrically connecting the electrode terminal and at least one electrode body. A power storage element having a power storage element, wherein the current collector is provided extending from a terminal connection portion electrically connected to the electrode terminal, two electrode body connection portions connected to at least one of the electrode bodies, and an end of the terminal connection portion, , A connection portion connecting the terminal connection portion and the two electrode body connection portions, wherein the connection portion has a width at a connection portion with the end portion of the terminal connection portion at a connection portion with the two electrode body connection portions. It is formed so as to be approximately trapezoidal wider than the width of.

According to this configuration, in the current collector, the terminal connection portion and the two electrode body connection portions are connected by a connection portion extending from the terminal connection portion. When the connecting portion is viewed from the side (when the current collector is viewed from the side opposite to the electrode body), the upper side connected to the end of the terminal connecting portion is connected to the lower side connected to the two electrode body connecting portions. ) has an approximately trapezoidal shape longer than

That is, the connection portion is formed so as to narrow in width as it approaches the two electrode body connection portions from the connection portion with the terminal connection portion, and thereby the posture of the two electrode body connection portions is an attitude suitable for connection with the electrode body. It is arranged without difficulty.

In this way, by forming the connecting portion of the current collector so that the width of the terminal connecting portion is approximately trapezoidal, which is longer than the width of the two electrode body connecting portions, occurrence of cracks or the like caused by bending is prevented without providing a notch in the connecting portion. It is possible to manufacture the entire collector.

Therefore, since there is no portion in the connection portion where the cross-sectional area is reduced due to the existence of the cutout, problems such as an increase in electrical resistance and a decrease in strength between the terminal connection portion and the two electrode body connection portions do not occur.

As described above, the power storage element of this embodiment is a power storage element provided with a highly reliable current collector.

Further, in the power storage element according to one aspect of the present invention, the area of the cross section parallel to the width direction and orthogonal to the outer surface of the coupling portion is the same as that of the two electrode bodies at any position in the extension direction of the coupling portion. It may be more than the sum of the areas of cross sections parallel to the width direction of the connecting portion.

According to this configuration, since there is no portion of the connecting portion having a cross-sectional area smaller than the sum of the cross-sectional areas of the two electrode body connecting portions, for example, when a large current flows between the terminal connecting portion and the two electrode body connecting portions, The reliability of the current collector is further improved.

In the power storage element according to one aspect of the present invention, the connecting portion may extend from a part of a side of the end portion of the terminal connecting portion.

According to this configuration, for example, the length of the terminal connecting portion in the width direction is formed relatively long, and the connecting portion is formed such that the position of the two electrode body connecting portions in the width direction is suitable for connection with one or more electrode bodies. can be installed That is, according to the current collector of this aspect, it is possible to reduce the electrical resistance at the terminal connection portion and to provide the connection portion and the two electrode body connection portions at positions suitable for connection with the electrode body.

Further, in the power storage element according to one aspect of the present invention, a notch is formed at a position on the side of the connection portion with the connection portion on the side of the end of the terminal connection portion. can be done with

According to this configuration, the process of bending the connection portion at the connection portion with the terminal connection portion, which is performed, for example, when manufacturing the current collector is facilitated, and the possibility of damage such as cracking is reduced. In addition, it becomes possible to prevent these effects from causing problems such as an increase in electrical resistance and a decrease in strength.

Further, in the power storage element according to one aspect of the present invention, the connection portion and each of the two electrode body connection portions may be connected by a curved portion.

Further, in the power storage element according to one aspect of the present invention, one of the two electrode body connection portions is connected to one of the two electrode bodies, and the other of the two electrode body connection portions is connected to the two electrode body connection portions. It may be connected to the other side of the electrode body.

In the power storage element according to one aspect of the present invention, the connecting portion may be positioned between the two electrode bodies in the arrangement direction of the two electrode bodies.

Further, in the power storage element according to one aspect of the present invention, the two electrode body connection portions may extend from the connection portion to the opposite side of the terminal connection portion.

In the power storage element according to one aspect of the present invention, the current collector may further have another electrode body connection portion extending from the terminal connection portion and arranged side by side with the two electrode body connection portions.

In the power storage element according to one aspect of the present invention, the connecting portion may have a bead portion.

Further, the present invention can be realized not only as a power storage element including the current collector according to any one of the above aspects, but also as the current collector.

According to the present invention, a power storage element having a highly reliable current collector can be provided.

1 is a perspective view schematically illustrating an external appearance of a power storage element according to an embodiment.
Fig. 2 is a perspective view illustrating each component included in the power storage element by removing the container body of the container of the power storage element according to one embodiment.
3 is an exploded perspective view of a power storage element according to an embodiment.
4 is a first perspective view illustrating a configuration of a positive electrode current collector according to an embodiment.
5 is a second perspective view showing the configuration of a positive electrode current collector according to an embodiment.
6 is a side view of a positive electrode current collector according to an embodiment when viewed from the side (positive side in the X-axis direction).
7 is a partially enlarged view of a positive electrode current collector according to a comparative example.
8 is a perspective view illustrating the appearance of a positive electrode current collector having a bead portion.
9 is a front view of a positive electrode current collector according to a modified example.
10 is a rear view of a positive electrode current collector according to a modified example.
11 is a plan view of a positive electrode current collector according to a modified example.
12 is a bottom view of a positive electrode current collector according to a modified example.
13 is a first side view of a positive electrode current collector according to a modified example.
14 is a second side view of a positive electrode current collector according to a modified example.
15 is a first perspective view of a positive electrode current collector according to a modified example.
16 is a second perspective view of a positive electrode current collector according to a modified example.
17 is a partial cross-sectional view of a positive electrode current collector according to a modified example.

Hereinafter, a power storage element according to an embodiment of the present invention will be described with reference to the drawings. In addition, the embodiment described below shows all comprehensive or specific examples. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In addition, among the components in the following embodiments, components not described in the independent claims representing the top-level concepts are described as arbitrary components.

In the following description and drawings, the vertical direction of the power storage element is defined as the Z-axis direction (hereinafter referred to as the first direction). That is, the Z-axis direction can be defined as a direction in which the leg portion (electrode body connecting portion) of the current collector is extended or installed, or the longitudinal direction of the end side of the container.

In addition, the arrangement direction of the two electrode bodies is defined as the Y-axis direction (hereinafter also referred to as the second direction or width direction). That is, the Y-axis direction can be defined as the opposite direction of the long side of the container, the width direction of the short side of the container, or the thickness direction of the container.

Further, a direction crossing the Z-axis direction and the Y-axis direction is defined as an X-axis direction (hereinafter referred to as a third direction). That is, the X-axis direction can be defined as the winding axis direction of the electrode body of the power storage element, the arrangement direction of the current collector or electrode terminals, or the opposite direction of the end side of the container.

And, although the Z-axis direction is the vertical direction, this vertical direction may be parallel to the vertical direction or may not be parallel. That is, there is no particular limitation on the posture of the power storage element when in use.

(Embodiment)

First, the configuration of the power storage element 10 according to the embodiment will be described.

1 is a perspective view schematically showing the appearance of a power storage element 10 according to an embodiment. FIG. 2 is a perspective view illustrating each component included in the power storage element 10 by removing the container body 111 of the container 100 of the power storage element 10 according to the embodiment.

3 is an exploded perspective view of power storage element 10 according to the embodiment. In addition, in FIG. 3, illustration of the container main body 111 of the container 100 is abbreviate|omitted.

The power storage element 10 is a power storage element including an electrode terminal, an electrode body, and a current collector electrically connecting the electrode terminal and the electrode body.

Specifically, the power storage element 10 is a secondary battery capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. In particular, the power storage element 10 is applied to an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV), or a hybrid electric vehicle (HEV). Incidentally, the power storage element 10 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, or may be a capacitor.

As shown in FIGS. 1 to 3 , the power storage element 10 includes a container 100 , a positive terminal 200 and a negative terminal 300 . In addition, upper insulating members 125 and 135 are disposed outside the container 100 . In addition, inside the container 100, the lower insulating members 120 and 130, the positive current collector 140, the negative current collector 150, the first electrode body 161 and the second electrode body 161 are two electrode bodies. The electrode body 162 is accommodated.

In addition, a liquid such as electrolyte solution (non-aqueous electrolyte solution) is sealed inside the container 100 of the power storage element 10, but illustration of the liquid is omitted. As the electrolyte solution sealed in the container 100, there is no particular restriction on the type, and various types can be selected as long as the performance of the power storage element 10 is not impaired.

The container 100 is composed of a container body 111 having a bottom in a rectangular tubular shape and a cover body 110 that is a plate-like member that closes the opening of the container body 111. In addition, the container 100 seals the internal space by accommodating the first electrode body 161, the second electrode body 162, etc. therein, and then welding the cover body 110 and the container body 111 or the like. has a structure that The material of the cover body 110 and the container body 111 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, or aluminum alloy.

The first electrode body 161 and the second electrode body 162 are two power generation elements arranged in parallel, and both are electrically connected to the positive electrode current collector 140 and the negative electrode current collector 150. do. Also, the first electrode body 161 and the second electrode body 162 have the same configuration.

Specifically, each of the first electrode body 161 and the second electrode body 162 includes an anode, a cathode, and a separator, and is a member capable of accumulating electricity. A positive electrode is one in which a positive electrode active material layer is formed on a positive electrode base layer, which is a long band-shaped metal foil made of aluminum or aluminum alloy or the like. In the negative electrode, a negative electrode active material layer is formed on a negative electrode base material layer that is a long band-shaped metal foil made of copper or a copper alloy. Further, the separator is a microporous sheet made of resin.

Here, as the positive electrode active material used for the positive electrode active material layer or the negative electrode active material used for the negative electrode active material layer, any known material can be suitably used as long as it is a positive electrode active material or negative electrode active material capable of intercalating and releasing lithium ions.

The first electrode body 161 and the second electrode body 162 are formed by winding a layered arrangement so that a separator is sandwiched between the positive electrode and the negative electrode. Incidentally, in FIGS. 2 and 3 , the shape of the first electrode body 161 and the second electrode body 162 is shown as a long circular shape, but a circular shape or an elliptical shape may be used. Also, the shape of the first electrode body 161 and the second electrode body 162 is not limited to a winding type, and may have a shape in which flat electrode plates are stacked.

Further, each of the first electrode body 161 and the second electrode body 162 has an anode-side end connected to the cathode current collector 140 and a cathode-side end connected to the cathode current collector 150. .

The anode-side end portion is the anode-side end portion of the electrode body in which the active material layer non-formation portions of the cathode are laminated and bundled, and the cathode-side end portion is the cathode-side end portion of the electrode body in which the active material layer non-formation portions of the cathode are laminated and bundled.

Further, the active material layer non-forming portion of the positive electrode is a portion of the positive electrode in which the positive electrode active material is not coated and the positive electrode base layer is exposed. The active material layer non-forming portion of the negative electrode is a portion of the negative electrode in which the negative electrode active material is not coated and the negative electrode base layer is exposed.

In this embodiment, the first electrode body 161 and the second electrode body 162 are bound by an insulating film.

As described above, since the power storage element 10 has a plurality of electrode bodies (two electrode bodies in this embodiment), compared to the case where a single electrode body is used for the container 100 having the same volume (volume). , is preferable in the following points.

That is, by using a plurality of electrode bodies, compared to the case of using a single electrode body, the dead space at the corners of the container 100 is reduced and the ratio occupied by the electrode bodies is improved, so that the storage capacity of the storage element 10 It leads to improvement (UP).

In particular, in an electrode body for high input/output (high rate), it is necessary to reduce the amount of active material on the metal foil compared to a high-capacity type electrode body, and the ratio of the metal foil or separator in the electrode body increases. Therefore, when a single electrode body is used, since the number of windings of the electrode increases, it is hard and has low flexibility, making it difficult to insert into the container 100. However, when a plurality of electrode bodies are used, the number of windings in one electrode body can be reduced, and as a result, an electrode body having high flexibility is realized.

The positive current collector 140 is disposed on the positive side of the first electrode body 161 and the second electrode body 162, and the positive terminal 200 and the first electrode body 161 and the second electrode body 162 It is a member equipped with conductivity and rigidity that is electrically connected to the anode of ). Also, the cathode current collector 140 is formed of aluminum or an aluminum alloy, similarly to the cathode substrate layers of the first electrode body 161 and the second electrode body 162 .

Specifically, the cathode current collector 140 is bonded to the anode side ends of the first electrode body 161 and the second electrode body 162 by welding or the like, and the first electrode body 161 and the second electrode body It is connected to the anode of the sieve 162. In addition, an opening 140a is formed in the positive current collector 140, and a connecting portion 210 of the positive electrode terminal 200 described later is inserted into the opening 140a and caulked, thereby forming the positive current collector 140. and the positive terminal 200 are connected.

The negative current collector 150 is disposed on the negative side of the first electrode body 161 and the second electrode body 162, and the negative electrode terminal 300 and the first electrode body 161 and the second electrode body 162 ) is a member having conductivity and rigidity electrically connected to the cathode of the The negative electrode current collector 150 is formed of copper or a copper alloy, similarly to the negative electrode base layers of the first electrode body 161 and the second electrode body 162 .

Specifically, the negative current collector 150 is bonded to the negative electrode side ends of the first electrode body 161 and the second electrode body 162 by welding or the like, and the first electrode body 161 and the second electrode body It is connected to the cathode of the sieve 162. In addition, an opening 150a is formed in the negative electrode current collector 150, and a connecting portion 310 of a negative electrode terminal 300 described later is inserted into the opening 150a and caulked, thereby forming the negative electrode current collector 150 and the negative terminal 300 are connected.

The lower insulating member 120 and the upper insulating member 125 are fixed to the cover 110 of the container 100 and are formed of an insulating resin or the like that insulates the cathode current collector 140 from the container 100. to be. An opening 120a is formed in the lower insulating member 120 into which a connecting portion 210 of the positive electrode terminal 200, which will be described later, is inserted, and an opening 120a into which the connecting portion 210 is inserted is formed in the upper insulating member 125. 125a is formed.

The lower insulating member 130 and the upper insulating member 135 are fixed to the cover body 110 of the container 100 and are formed of insulating resin or the like to insulate the negative current collector 150 from the container 100. to be. An opening 130a into which a connecting portion 310 of a negative electrode terminal 300 described later is inserted is formed in the lower insulating member 130, and an opening into which the connecting portion 310 is inserted into the upper insulating member 135. 135a is formed.

The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the first electrode body 161 and the positive electrode of the second electrode body 162, and the negative electrode terminal 300 is an electrode terminal of the first electrode body 161. It is an electrode terminal electrically connected to the negative electrode and the negative electrode of the second electrode body 162 . The positive terminal 200 and the negative terminal 300 are attached to the cover body 110 disposed above the first electrode body 161 and the second electrode body 162 .

As shown in FIG. 3 , the positive terminal 200 is provided with a connecting portion 210 that electrically connects the positive terminal 200 and the positive current collector 140 .

The connecting portion 210 is a member that is inserted into the opening 140a of the positive current collector 140 and connected to the positive current collector 140, and is, for example, a rivet. That is, the connection part 210 includes the opening 125a of the upper insulating member 125, the through hole 110a of the cover body 110, the opening 120a of the lower insulating member 120, and the positive current collector. It is inserted into the opening (140a) of (140) and caulked. Thus, the positive electrode terminal 200 is fixed to the cover body 110 together with the upper insulating member 125 , the lower insulating member 120 , and the positive current collector 140 .

Similarly, the negative terminal 300 is provided with a connecting portion 310 that electrically connects the negative terminal 300 and the negative current collector 150 . The connector 310 is a member that is inserted into the opening 150a of the negative electrode current collector 150 and connected to the negative electrode current collector 150, and is, for example, a rivet. That is, the connection part 310 includes the opening 135a of the upper insulating member 135, the through hole 110b of the cover body 110, the opening 130a of the lower insulating member 130, and the negative current collector. It is inserted into the opening (150a) of (150) and caulked. Thus, the negative electrode terminal 300 is fixed to the cover body 110 together with the upper insulating member 135 , the lower insulating member 130 , and the negative electrode current collector 150 .

Next, the configurations of the positive current collector 140 and the negative current collector 150, which are characteristics of the power storage element 10 according to the present embodiment, will be described in detail. In addition, since the cathode current collector 140 and the anode current collector 150 have the same configuration, the description of the cathode current collector 140 will be given below and the description of the anode current collector 150 will be omitted. That is, structural features of the cathode current collector 140 described below are also applied to the anode current collector 150 .

4 is a first perspective view showing the configuration of a positive electrode current collector 140 according to an embodiment. Specifically, FIG. 4 is a perspective view of the positive electrode current collector 140 shown in FIG. 3 when viewed from the right side and obliquely upward.

5 is a second perspective view showing the configuration of a positive electrode current collector 140 according to an embodiment. Specifically, FIG. 5 is a perspective view of the positive electrode current collector 140 shown in FIG. 3 when viewed from the inside and obliquely downward.

6 is a side view of the positive current collector 140 according to one embodiment when viewed from the side (positive side in the X-axis direction).

As shown in these figures, the positive current collector 140 includes a terminal connection portion 141 and a plurality of legs (in this embodiment, the outer legs 142 and 143 and the inner legs 144 and 145). four leg parts] and a connecting part 148. Each of these plural leg portions is an example of an electrode body connection portion connected to at least one electrode body. In particular, the inner leg portions 144 and 145 are examples of two electrode body connection portions connected to the terminal connection portion 141 by the connection portion 148 .

Specifically, by performing processing such as bending processing, drawing processing, ironing processing, and torsion processing on a plate material of a predetermined shape made of aluminum alloy or the like, the terminal connection portion 141, A cathode current collector 140 integrally equipped with a plurality of leg parts 142 to 145 and a connection part 148 is manufactured.

The terminal connecting portion 141 is a member electrically connected to the positive terminal 200, and in the present embodiment is a substantially rectangular and flat member. An opening 140a is formed in the terminal connecting portion 141 . The connection part 210 of the positive terminal 200 is inserted into the opening 140a and caulked so that the positive terminal 200 and the terminal connection part 141 are electrically and mechanically connected.

The opening 140a is a circular through hole formed in the terminal connecting portion 141 , and specifically has a shape corresponding to the external shape of the connecting portion 210 . The shape of the opening portion 140a is not limited to a circular shape, and may be an elliptical shape or a square shape, but it is preferably a shape corresponding to the external shape of the connecting portion 210. Further, the opening 140a may not be a through hole as long as the connecting portion 210 is inserted, and may be a semicircular or rectangular cutout, or the like.

In the present embodiment, as shown in FIG. 4 , for example, a substantially rectangular opening is formed in the positive electrode current collector 140 in addition to the opening 140a. This is, for example, an opening for accommodating a protruding portion on the back side (positive electrode current collector 140 side) of the lower insulating member 120, and is not an essential element for the positive electrode current collector 140.

Each of the plurality of legs (outer leg portions 142 and 143 and inner leg portions 144 and 145) is a long member in the Z-axis direction. Among these plural leg portions, two leg portions (inner leg portions 144 and 145) are arranged side by side in the Y-axis direction and connected to the terminal connection portion 141 by a connecting portion 148. The inner leg portions 144 and 145 extend from the connection portion 148 to the opposite side of the terminal connection portion 141 . Incidentally, the inner leg portions 144 and 145 protrude from the connection portion 148 to the opposite side of the terminal connection portion 141 and are provided.

The connecting portion 148 extends from the end of the terminal connecting portion 141 . Specifically, the connecting portion 148 extends from the end of the terminal connecting portion 141 on the positive side in the X-axis direction to the negative side in the Z-axis direction.

The other electrode body connecting portions (each of the outer leg portions 142 and 143) extend from the terminal connecting portion 141 and are connected to the connecting portion 148, the inner leg portions 144 and 145, and the Y-axis direction. are placed side by side. Also, as another electrode body connecting portion, only one of the outer leg portions 142 and 143 may be provided on the positive current collector 140 .

Here, the anode side ends of the first electrode body 161 and the second electrode body 162 have side surfaces along the X-axis direction, as shown in FIG. 3 , for example. That is, each of the four elongated and flat leg portions is, for example, a bonding surface for improving the accuracy of bonding with the first electrode body 161 or the second electrode body 162. It is preferable that it is a posture parallel to this X-axis direction (position whose thickness direction is orthogonal to the X-axis direction).

In the present embodiment, each of the outside leg portions 142 and 143 extends from a parallel side in the X-axis direction of the plate-shaped terminal connection portion 141 . That is, each of the outer leg portions 142 and 143 is formed such that a long portion extending from the terminal connecting portion 141 is bent by approximately 90° along a side parallel to the X-axis direction. As a result, each of the outer leg portions 142 and 143 has a posture in which the bonding surfaces are parallel to the X-axis direction.

However, the inner leg portions 144 and 145 are provided in succession to the connecting portion 148 extending from the parallel side 141a of the terminal connection portion 141 in the Y-axis direction.

That is, only in the step of bending the connecting portion 148 by approximately 90° along the parallel side 141a in the Y-axis direction at the connecting portion with the terminal connecting portion 141 (first bending step), the inner leg portion 144 and 145) are in a parallel state in the Y-axis direction.

Therefore, before or after the first bending step or at the same time, the inner leg portion with respect to the connecting portion 148 so that the joint surfaces of the inner leg portions 144 and 145 are parallel to the X-axis. A step of bending 144 and 145 by approximately 90° and drawing (second bending step) is required.

Further, for example, by twisting the inner leg 144 at a position midway in the longitudinal direction, the bonding surface of the inner leg 144 can be made parallel to the X-axis direction. However, in this case, the length that can be joined to the first electrode body 161 of the inner leg portion 144 is shortened, and the unnecessary space between the first electrode body 161 and the terminal connection portion 141 increases. do. This also applies to the inner leg portion 145 bonded to the second electrode body 162 .

Therefore, at a position relatively close to the terminal connecting portion 141, it is required to perform bending to make the joint surfaces of the inner leg portions 144 and 145 parallel to the X-axis direction.

So, for example, a structure such as the positive current collector 540 shown in FIG. 7 can be considered.

7 is a partially enlarged view of a positive electrode current collector 540 according to a comparative example.

The positive electrode current collector 540 shown in FIG. 7 includes a terminal connecting portion 541, elongated inner leg portions 544 and 545 in the Z-axis direction, and a terminal connecting portion 541 and inner leg portions 544 and 545. It is provided with a connection portion 548 connecting the.

In the positive current collector 540 shown in FIG. 7 , leg portions (inner leg portions 544 and 545 ) are connected to both ends of the connecting portion 548 in the Y-axis direction. In addition, both ends in the Y-axis direction of the connecting portion 548 are bent at approximately 90° along a bending line parallel to the Z-axis direction, and inner leg portions 544 and 545 having joint surfaces parallel to the X-axis are formed. .

However, in this case, in order to prevent breakage such as cracks caused by being bent at approximately 90°, each of the sides parallel to the Z-axis direction at both ends of the Y-axis direction is attached to the connecting portion 548, as shown in FIG. 7 . , a semi-cylindrical notch 548a for relieving stress concentration is provided. The notch 548a is formed in a concave shape in the Y-axis direction from the side.

Thus, in the connecting portion 548, in the extension direction (the direction from the terminal connecting portion 541 toward the inner leg portions 544 and 545), there exists a portion with a smaller cross-sectional area than the front and back sides. This causes problems such as an increase in electrical resistance and a decrease in strength.

Therefore, in the positive electrode current collector 140 according to the present embodiment, as shown in FIGS. 4 to 6 , the Y-axis direction of the connection portion 148 starts from the vicinity of the connection portion of the connection portion 148 with the terminal connection portion 141. Gradually bend both ends of Specifically, the length of the portion parallel to the X-axis direction becomes longer as it approaches the inner leg portions 144 and 145 (going downward in FIGS. 4 to 6) of the connecting portion 148. Both ends in the Y-axis direction are bent and drawn.

That is, the 2nd bending process is demonstrated as follows. The first electrode body ( 161) and the second electrode body 162 are bent and drawn (for example, press using a mold).

As a result, as shown in FIG. 6, for example, on the outer surface 149 of the connecting portion 148, which is the side opposite to the first electrode body 161 and the second electrode body 162, downward as a whole. A pair of bent lines 147 gradually narrowing the gap may be formed.

That is, as shown in FIG. 6 , in the connecting portion 148, the width D1 in the Y-axis direction at the connecting portion of the outer surface 149 to the end of the terminal connecting portion 141 is the inner leg portion 144 and 145) is formed so as to be substantially trapezoidal wider than the width D2 in the Y-axis direction in the connecting portion. In addition, a perfect trapezoidal shape is also included as a substantially trapezoidal shape.

In addition, although the bending line 147 is shown as a clear solid line in FIG. 6 for the convenience of explanation, the bending line 147 is not necessarily recognized as a clear line in appearance.

Thus, in this embodiment, the connecting portion 148 is formed such that the outer surface 149 is substantially trapezoidal. Specifically, the outer surface 149 has a wide width D1 at a portion connected to the end of the terminal connecting portion 141 and a narrow width D2 at a portion connected to the inner leg portions 144 and 145. It is approximately trapezoidal.

That is, a joint surface parallel to the X-axis is not provided at the end of the bending line 147 between the connecting portion 148 and the inner leg portions 144 and 145 to prevent cracking (relaxation of stress concentration). The inner leg portions 144 and 145 having are formed without difficulty. Accordingly, there is no portion in the connecting portion 148 having a small cross-sectional area due to providing a notch, and thus, a highly reliable positive electrode current collector 140 can be obtained.

More specifically, in the positive electrode current collector 140 of the present embodiment, as shown in FIG. 4 , for example, the cross-sectional area Sa of the connecting portion 148 is the inner leg portion 144 at any position of the connecting portion 148. and 145) is greater than or equal to (2Sb) the sum of the cross-sectional areas.

Incidentally, between the inner legs 144 and 145 and the terminal connecting portion 141, there is no portion with a cross-sectional area smaller than the sum of the cross-sectional areas of the inner legs 144 and 145 (2Sb).

Accordingly, there is no high-resistance location between the terminal connection portion 141 and the inner leg portions 144 and 145 in the connecting portion 148 . Therefore, the reliability of the positive current collector 140 is further improved when a large current flows between the terminal connecting portion 141 and the inner leg portions 144 and 145 .

Further, the cross-sectional area Sa of the connecting portion 148 is a cross-sectional area parallel to the Y-axis direction (width direction) and orthogonal to the outer surface 149 . Further, each cross-sectional area Sb of the inner legs 144 and 145 is the area of a cross-section orthogonal to the Z-axis direction (cross-section parallel to the width direction).

Further, in this embodiment, the cross-sectional areas of the inner legs 144 and 145 are all indicated by Sb, but the cross-sectional areas of the inner legs 144 and the cross-sectional areas of the inner legs 145 may be different.

For example, it is assumed that the cross-sectional area of the inner leg 144 is Sb1 and the cross-sectional area of the inner leg 145 is Sb2 (≠Sb1). In this case, in the positive current collector 140, the cross-sectional area Sa of the connecting portion 148 is greater than or equal to the sum of the cross-sectional areas of the inner legs 144 and 145 (Sb1 + Sb2) at any position of the connecting portion 148.

Moreover, as shown in FIGS. 4-6, the connection part 148 extends from part of the side 141a of the edge part of the terminal connection part 141. Specifically, the connection portion 148 extends from a part of the side 141a parallel to the Y-axis direction (width direction) in the plate-shaped terminal connection portion 141, which is an end portion of the terminal connection portion 141. .

That is, in the terminal connection portion 141 having a relatively wide width in the Y-axis direction, the positions of the inner leg portions 144 and 145 in the Y-axis direction are different from those of the first electrode body 161 and the second electrode body 162. The connecting portion 148 is provided so as to be in a suitable position for connection.

In this embodiment, the width D1 (see FIG. 6 ) in the Y-axis direction at the connection portion of the outer surface 149 of the connection portion 148 with the end of the terminal connection portion 141 is It is smaller than the width of the side (141a) of the end. Moreover, the connection part 148 is provided in the center part of the width direction in the side 141a of the end part of the terminal connection part 141.

In this way, according to the positive electrode current collector 140 according to the present embodiment, for example, the electrical resistance in the terminal connection portion 141 is reduced, and the connection portion ( 148) and inner leg portions 144 and 145.

In addition, the positive electrode current collector 140 according to the present embodiment extends from the terminal connecting portion 141 and has another long leg in the Z-axis direction arranged side by side with the inner legs 144 and 145 in the Y-axis direction. It has parts (outer leg parts 142 and 143).

In this way, the positive current collector 140 can be disposed so that each of the plurality of electrode bodies (first electrode body 161 and second electrode body 162 ) is held by the two legs.

Here, in the positive electrode current collector 540 in the comparative example shown in FIG. 7 , notches 546 are also provided at the bases of the inner leg portions 544 and 545 . That is, notches 546 are provided at the bases of the inner legs 544 and 545 so that cracks or the like do not occur in the bases of the inner legs 544 and 545 during bending to form them.

On the other hand, in the positive electrode current collector 140 of this embodiment, as shown in FIGS. 4 to 6 , there is no notch at the base of the inner legs 144 and 145 .

Specifically, as can be seen from FIG. 6, for example, the outer shape of these root portions (connection portions between the inner leg portions 144 and 145 and the connecting portion 148) is composed of gentle curves when viewed from the side. has been Thereby, the stress concentration in these base parts is alleviated. Therefore, in the positive electrode current collector 140 according to the present embodiment, the notch 546 like the positive electrode current collector 540 in the comparative example is unnecessary.

In this way, since no cutout exists in the inner leg portions 144 and 145, they do not have a portion where the cross-sectional area is reduced due to the presence of the notch. Therefore, in the inner leg portions 144 and 145, problems such as an increase in electrical resistance and a decrease in strength do not occur.

In this embodiment, the power storage element 10 includes two electrode bodies (first electrode body 161 and second electrode body 162), and the inner leg portion 144 includes the first electrode body. It is connected to the body 161, and the inner leg part 145 is connected to the second electrode body 162. That is, electrical connection between the two electrode bodies (the first electrode body 161 and the second electrode body 162) and the positive terminal 200 is provided by one member (the positive electrode current collector 140), there is.

In addition, the connecting portion 148 connecting the terminal connection portion 141 and the inner leg portions 144 and 145 is in the arrangement direction (Y-axis direction) of the first electrode body 161 and the second electrode body 162. , located between the first electrode body 161 and the second electrode body 162.

Thus, for example, conditions such as electrical resistance between each of the first electrode body 161 and the second electrode body 162 and the positive terminal 200 are equalized. Also, for example, the first electrode body 161 and the second electrode body 162 are supported in a good balance by the positive electrode current collector 140 .

In the above, the power storage element according to the present invention will be described based on the embodiments. However, the present invention is not limited to the above embodiment. As long as it does not deviate from the spirit of the present invention, various modifications that can be thought of by those skilled in the art to the above embodiments, or forms constructed by combining a plurality of components described above are also included within the scope of the present invention.

For example, processing may be performed on the cathode current collector 140 to reinforce the connecting portion 148 connected to the two leg portions (inner leg portions 144 and 145).

8 is a perspective view showing an external appearance of the positive electrode current collector 140 having a bead portion.

The connecting portion 148 of the positive electrode current collector 140 shown in FIG. 8 has a bead portion 149a. The bead portion 149a is a reinforcing portion formed on the connecting portion 148 to increase the strength of the connecting portion 148 .

The bead portion 149a is formed to protrude in the thickness direction of the connection portion 148 . Specifically, the bead portion 149a extends in the vertical direction (Z-axis direction) from the central portion of the coupling portion 148 and protrudes to the inside of the positive current collector 140 (to the negative side in the X-axis direction). is formed to That is, the bead portion 149a is provided in a concave shape recessed from the outer surface 149 and is formed by a portion protruding from the inner side (minus side in the X-axis direction) surface of the connecting portion 148 .

The bead portion 149a may be provided in a concave shape recessed into the inner side (minus side in the X-axis direction) of the connecting portion 148 and formed by a portion protruding from the outer side surface 149 . Further, the bead portion 149a may protrude from one side and the other side may have a flat configuration.

As described above, since the bead portion 149a is formed in the connection portion 148 of the cathode current collector 140 , the strength of the cathode current collector 140 can be improved. Accordingly, vibration resistance or impact resistance of the power storage element 10 including the positive current collector 140 can be improved.

Moreover, in this embodiment, the pair of bending lines 147 formed in the coupling part 148 is an inwardly convex curve in FIG. 6, but may be an outwardly convex curve. Moreover, each of a pair of bending lines 147 may be comprised by a straight line.

That is, the pair of bending lines 147 need only be formed so that the interval narrows downward as a whole, and for example, a section in which the interval is wider than immediately above it may be included in a part of the vertical direction. .

In addition, the positive electrode current collector 140 of this embodiment has four leg portions 142 to 145. However, the positive current collector 140 of this embodiment only needs to have at least two leg parts.

Specifically, the positive electrode current collector 140 has two electrode body connection parts (inner leg parts 144 and 145 according to the present embodiment) connected to the terminal connection part 141 by the connection part 148, and other It is not necessary to have an electrode body connection part.

That is, even when the positive current collector 140 has no other legs, the effect of forming the two legs connected to the connecting portion 148 can be smoothly performed without having a notch, and the effect can be obtained.

Further, when the positive electrode current collector 140 has only the inner leg portions 144 and 145 as the electrode body connection portions, the positive electrode side end of one electrode body is clamped by the inner leg portions 144 and 145 to collect the positive electrode body. You may arrange the whole 140.

That is, the number of electrode bodies included in the power storage element 10 does not have to be plural, and it is sufficient to include at least one electrode body. That is, the number of electrode bodies included in the power storage element 10 may be "1".

In the above embodiment, the connecting portion 148 of the positive electrode current collector 140 is disposed between two adjacent electrode bodies 161 and 162 in the Y-axis direction. The position may be the side of any one of the electrode bodies or the like. That is, the connection part 148 may be arrange|positioned at any position of the side 141a parallel to the Y-axis direction of the terminal connection part 141.

In the above embodiment, the positive current collector 140 and the positive terminal 200 are connected by caulking the connecting portion 210, but the positive current collector 140 and the positive terminal 200 The connection method of ) is not limited to crimping, and any method may be employed.

In the above embodiment, the negative electrode current collector 150 has the same configuration as the positive electrode current collector 140, but only the positive electrode current collector 140 may have the above configuration. Alternatively, only the negative electrode current collector 150 may have the above configuration.

(modified example)

In the positive electrode current collector 140 according to the above embodiment, there is no notch for crack prevention (relaxation of stress concentration) during processing such as bending, and the existence of the notch increases electrical resistance, etc. It turned out that there was no problem.

However, the positive current collector 140 is an aspect that prevents problems such as an increase in electrical resistance, for example, and may be provided with notches to prevent cracking (relieving stress concentration) during processing such as bending. do. Therefore, as a modified example of the embodiment, a current collector having characteristics common to the positive electrode current collector 140 according to the above embodiment and having a notch (notch) for crack prevention (relaxation of stress concentration), It demonstrates with reference to FIGS. 9-17.

The positive current collector 240 described below is a member that can be used by replacing the positive current collector 140 in the power storage element 10 according to the embodiment (see FIG. 2 for example). In addition, the following description is given as the positive side in the X-axis direction is taken as the front.

9 is a front view of a positive electrode current collector 240 according to a modified example. 10 is a rear view of a positive electrode current collector 240 according to a modified example. 11 is a plan view of a positive electrode current collector 240 according to a modified example. 12 is a bottom view of a positive electrode current collector 240 according to a modified example. 13 is a first side view of a positive electrode current collector 240 according to a modified example. 14 is a second side view of a positive electrode current collector 240 according to a modified example. 13 shows the positive current collector 240 when viewed from the positive side in the Y-axis direction, and FIG. 14 shows the positive current collector 240 when viewed from the negative side in the Y-axis direction.

15 is a first perspective view of a positive electrode current collector 240 according to a modified example. 16 is a second perspective view of a positive electrode current collector 240 according to a modified example. 17 is a partial cross-sectional view of a positive electrode current collector 240 according to a modified example. In addition, in FIG. 17, the A-A line enlarged sectional view in the B-B part shown in FIG. 9 is shown.

As shown in FIGS. 9 to 17 , the positive current collector 240 according to this modified example includes a terminal connecting portion 241 and a plurality of leg parts (in this modified example, the outer leg parts 242 and 243 and Four leg parts of the inner leg parts 244 and 245] and a connection part 248.

The terminal connecting portion 241 is a member electrically connected to the positive terminal 200 and has an opening 240a formed therein. The connection part 210 of the positive terminal 200 is inserted into the opening 240a and caulked so that the positive terminal 200 and the terminal connection part 241 are electrically and mechanically connected.

Each of the plurality of legs (outer leg portions 242 and 243 and inner leg portions 244 and 245) is a long member in the Z-axis direction. Among these plural leg portions, two leg portions (inside leg portions 244 and 245) are arranged side by side in the Y-axis direction and connected to the terminal connection portion 241 by a connecting portion 248. The inner leg portions 244 and 245 extend from the connection portion 248 to the opposite side of the terminal connection portion 241 .

The other legs (each of the outer legs 242 and 243) extend from the terminal connecting portion 241 and are connected to the connecting portion 248, and the inner legs 244 and 245, in the Y-axis direction. are placed side by side.

The connecting portion 248 extends from an end of the terminal connecting portion 241 . Specifically, the connecting portion 248 is a side 241a of the positive side end of the terminal connecting portion 241 in the X-axis direction, and extends from the parallel side 241a in the Y-axis direction to the minus side in the Z-axis direction. there is.

In addition, as shown in FIG. 9, for example, in the connection portion 248, the width D3 in the Y-axis direction at the connection portion of the outer surface 249 with the end portion of the terminal connection portion 241 is the inner leg portion. It is formed so that it may become substantially trapezoidal wider than the width D4 of the Y-axis direction in the connection part with 244 and 245. That is, similarly to the positive electrode current collector 140 according to the above embodiment, the postures of the inner legs 244 and 245 are properly adjusted to a posture suitable for connection with the electrode body.

Specifically, both ends in the Y-axis direction of the coupling portion 248 are moved to the inside so that the width of the outer surface 249 of the coupling portion 248 in the Y-axis direction narrows as the inner leg portions 244 and 245 get closer. (For example, press using a mold). As a result, the connecting portion 248 is formed in a substantially trapezoidal shape. In addition, by bending and drawing in this way, the thickness direction of the connecting portion 248 and the inner leg portions 244 and 245 are different from each other. In this modified example, the thickness direction of the connecting portion 248 is the X-axis direction, and the thickness direction of each of the inner leg portions 244 and 245 is the Y-axis direction.

The connecting portion 248 and the inner leg portions 244 and 245 having different thickness directions are connected by a curved portion 248a as shown in FIG. 12 . Also, in the positive electrode current collector 140 according to the above embodiment, as can be seen from the shape of the cross section of the connecting portion 148 shown in, for example, FIG. The connecting portion 148 having different directions and the inner leg portions 144 and 145 are connected by a curved portion.

In this way, the basic structure of the positive current collector 240 according to the present modified example is the same as that of the positive current collector 140 according to the above embodiment. That is, the positive current collector 240 according to the present modified example includes a terminal connecting portion 241 electrically connected to the positive terminal 200 and two leg portions (inner leg portion 244 and 244) connected to one or more electrode bodies. 245)], and a connecting portion 248 extending from the end of the terminal connecting portion 241 and connecting the terminal connecting portion 241 and the inner leg portions 244 and 245. Further, the connecting portion 248 is formed such that the width at the portion connected to the end of the terminal connecting portion 241 is substantially trapezoidal, wider than the width at the portion connected to the inner leg portions 244 and 245. .

In the cathode current collector 240 according to the present modified example, in addition to the above configuration, a cutout portion ( 241b) is formed.

Specifically, as shown in FIG. 11 , for example, the cutout portion 241b is the positive terminal in the terminal connection portion 241 from the side 241a of the end of the terminal connection portion 241 in plan view. It is a portion formed concave toward the connection portion with 200 (ie, opening 240a).

That is, in the direction connecting the inner leg portions 244 and 245 and the positive terminal 200 (the X-axis direction in this modified example), there is no portion having a smaller cross-sectional area than the front and back, and the terminal connection portion ( 241 is provided with a cutout 241b. More specifically, in the terminal connecting portion 241, cutout portions 241b are provided on each of both sides of the connecting portion with the connecting portion 248.

Thus, a process of bending the connection portion 248 along the parallel side 241a in the Y-axis direction at a connection portion with the terminal connection portion 241 by approximately 90°, which is performed when the positive current collector 240 is manufactured (the first step). 1 bending process) becomes easy. In addition, in the first bending step, stress concentration in the connection portion is alleviated, and as a result, the possibility of damage such as cracking is reduced. In addition, effects such as facilitation of the first bending step or suppression of breakage can be obtained without causing problems such as an increase in electrical resistance and a decrease in strength.

Incidentally, the cutout portion 241b does not need to be formed by actually cutting (cutting) the end portion of the terminal connection portion 241 . For example, the notch 241b may be formed by press work for forming the overall shape of the terminal connecting portion 241 .

In addition, in the positive electrode current collector 240 according to the present modified example, as in the positive electrode current collector 140 shown in FIG. strength is improved. As a result, the vibration resistance or impact resistance of the power storage element 10 including the positive current collector 240 can be improved.

In addition, various characteristics of the positive current collector 240 according to the present modified example may be provided in the current collector connected to at least one of the negative electrodes of the first electrode body 161 and the second electrode body 162 .

[Industrial Applicability]

INDUSTRIAL APPLICABILITY The present invention can be applied to power storage devices such as lithium ion secondary batteries and the like.

10: power storage element
100: courage
110: cover body
110a, 110b: through hole
111: container body
120, 130: lower insulating member
120a, 125a, 130a, 135a, 140a, 150a, 240a: opening
125, 135: upper insulating member
140, 240: positive current collector
141, 241: terminal connection part
141a, 241a: sides
142, 143, 242, 243: outer leg
144, 145, 244, 245: inner leg
147: warp line
148, 248: connection part
149, 249: outer surface
149a, 249a: bead part
150: negative electrode current collector
161: first electrode body
162: second electrode body
200: positive terminal
210, 310: connection part
241b: cutout
300: negative terminal

Claims (10)

A power storage element comprising an electrode terminal, at least one electrode body, and a current collector electrically connecting the electrode terminal and the at least one electrode body,
The whole house,
a terminal connecting portion electrically connected to the electrode terminal;
two electrode body connection portions connected to at least one of the electrode bodies; and
A connection portion extending from an end of the terminal connection portion and connecting the terminal connection portion and the two electrode body connection portions,
The parallel direction of the two electrode body connection portions is the width direction,
A length in the width direction at a connection portion of the connection portion with the end portion of the terminal connection portion is set as a first width, and a width direction at a connection portion of the connection portion with the two electrode body connection portions As the length of, when the length in the width direction of the end of the outer surface of the connection portion on the side of the two electrode body connection portions is the second width,
The connecting portion is formed such that the first width is a trapezoid wider than the second width,
The area of the cross section of the connecting portion parallel to the width direction and orthogonal to the outer surface is equal to the area of the cross section parallel to the width direction of the two electrode body connection portions at any position in the extension direction of the connecting portion. more than the sum,
storage element. According to claim 1,
The power storage element, wherein the connecting portion extends from a part of a side of the end of the terminal connecting portion. According to claim 2,
The power storage element according to claim 1 , wherein a cutout portion is formed at a side of the end portion of the terminal connection portion on a side of the connection portion with the connection portion. According to any one of claims 1 to 3,
The power storage element, wherein the connection portion and each of the two electrode body connection portions are connected by a curved portion. According to any one of claims 1 to 3,
One of the two electrode body connecting portions is connected to one of the two electrode bodies, and the other of the two electrode body connecting portions is connected to the other of the two electrode bodies. According to claim 5,
The power storage element, wherein the connecting portion is located between the two electrode bodies in an arrangement direction of the two electrode bodies. According to any one of claims 1 to 3,
The electrical storage element according to claim 1 , wherein the two electrode body connecting portions extend from the connecting portion to a side opposite to the terminal connecting portion. According to any one of claims 1 to 3,
The power storage element, wherein the current collector further has another electrode body connection portion extending from the terminal connection portion and arranged side by side with the two electrode body connection portions. According to any one of claims 1 to 3,
The power storage element, wherein the connecting portion has a bead portion. delete

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