JP7654093B2 - battery - Google Patents

Description

An embodiment of the present invention relates to a battery.

Some batteries, such as lithium ion secondary batteries, have an electrode group including a positive electrode and a negative electrode housed in the internal cavity of an exterior member. In this battery, an electrode terminal is provided on the exterior member. The electrode group also includes a current collector and an active material-containing layer supported on the current collector. The current collector includes a current collecting tab as a portion not supported by the active material-containing layer. The current collecting tab is electrically connected to the electrode terminal via a current collecting connection plate such as a lead. In the current collecting tab, multiple strip-shaped portions are stacked.

When manufacturing the battery described above, the multiple stacked strips of the current collector tabs are joined to the current collector connection plate, for example, by ultrasonic bonding. When the strips and the current collector connection plate are joined in this manner, the strips may be deformed during joining, causing the strips and the current collector tabs themselves to shift from their designated positions. In such joining, it is necessary for the current collector tabs to be joined in the appropriate positions on the current collector connection plate.

Japanese Patent Application Publication No. 2015-103521 Japanese Patent Application Publication No. 2015-092457 Japanese Patent Application Publication No. 2011-192547 Japanese Patent Application Publication No. 2011-165437 Japanese Patent Application Publication No. 2011-119264

The problem that this invention aims to solve is to provide a battery in which a current collector tab can be joined to an appropriate position on a current collector connection plate.

The battery of the embodiment includes an exterior member, an electrode terminal, an electrode group, and a current collecting connection plate. The electrode terminal is provided on the exterior member. The electrode group is housed in an internal cavity of the exterior member and includes a protruding current collecting tab. The current collecting connection plate electrically connects the electrode terminal and the current collecting tab. The current collecting connection plate includes a substrate portion and a protruding portion. The substrate portion includes a joint surface to be joined to the current collecting tab, and the joint surface faces one side in a first direction. The protruding portion is formed close to the protruding end of the current collecting tab in a second direction intersecting with the first direction, and protrudes from the substrate portion to a side to which the joint surface faces in the first direction. The protruding portion includes a proximity surface that is closer to the current collecting tab from a side where the exterior member is located in the second direction than the protruding end of the current collecting tab and faces the side where the protruding end of the current collecting tab is located. The proximal surface extends in a first direction to a protruding end of the protrusion, and the protruding end of the protrusion extends in a second direction from the proximal surface to an end of the current collecting connection plate.

FIG. 1A is a perspective view that illustrates a schematic example of a battery according to an embodiment. FIG. 1B is a perspective view that illustrates an example of a current collector connection plate that is joined to a current collector tab of a battery according to an embodiment. FIG. 2 is a cross-sectional view that shows, in a cross section perpendicular to the height direction of the battery, a schematic example of the configuration of a portion where the current collecting tab and the current collecting connection plate in FIG. 1B are joined. FIG. 3 is a cross-sectional view that shows a schematic cross section perpendicular to the height direction of the battery, showing a modified configuration of the portion where the current collecting tab and the current collecting connection plate in FIG. 1B are joined. FIG. 4 is a cross-sectional view that shows, in a cross section perpendicular to the height direction of the battery, a modified example of the configuration of the portion where the current collecting tab and the current collecting connection plate in FIG. 1B are joined, which is different from that shown in FIG. FIG. 5 is a cross-sectional view that shows a schematic cross section of a modified example of the battery according to the embodiment, the cross section being perpendicular to the depth direction of the battery. FIG. 6 is a cross-sectional view that shows a schematic cross section of a modified example of the battery according to the embodiment, taken along a cross section perpendicular to the lateral direction of the battery.

The following describes the embodiments with reference to the drawings.

(Embodiment)
FIG. 1A shows a battery 1 according to an embodiment. As shown in FIG. 1A, the battery 1 includes an electrode group 2 and an exterior member 3. The exterior member 3 includes an exterior container 5 and a lid member 6. The exterior container 5 and the lid member 6 are each formed of a metal such as aluminum, an aluminum alloy, iron, copper, or stainless steel. Here, in the battery 1 (exterior container 5), a depth direction (direction indicated by arrows X1 and X2), a lateral direction (direction indicated by arrows Y1 and Y2) intersecting (perpendicular or substantially perpendicular) with respect to the depth direction, and a height direction (direction indicated by arrows Z1 and Z2) intersecting (perpendicular or substantially perpendicular) with respect to both the depth direction and the lateral direction are defined. In each of the battery 1 and the exterior container 5, the dimension in the depth direction is smaller than the dimension in the lateral direction and the dimension in the height direction. Note that FIG. 1A is a perspective view showing each member disassembled.

The outer container 5 has a bottom wall 7 and a peripheral wall 8. The internal cavity 10 in which the electrode group 2 is housed is defined by the bottom wall 7 and the peripheral wall 8. In the outer container 5, the internal cavity 10 opens in the height direction toward the side opposite the side on which the bottom wall 7 is located. The lid member 6 is attached to the peripheral wall 8 at the end opposite the bottom wall 7. Thus, the lid member 6 closes the opening of the internal cavity 10 of the outer container 5. The lid member 6 and the bottom wall 7 face each other in the height direction, sandwiching the internal cavity 10 therebetween.

The electrode group 2 includes a pair of electrodes 13, a pair of collectors 14, and a pair of collector tabs 15. One of the pair of electrodes 13 is a positive electrode 13A, and the other of the pair of electrodes 13 is a negative electrode 13B. One of the pair of collectors 14 is a positive electrode collector 14A, and the other of the pair of collectors 14 is a negative electrode collector 14B. One of the pair of collector tabs 15 is a positive electrode collector tab 15A, and the other of the pair of collector tabs 15 is a negative electrode collector tab 15B. In each of the pair of collector tabs 15, a plurality of strip-shaped portions are bundled. In the electrode group 2, a separator (not shown) is interposed between the positive electrode 13A and the negative electrode 13B. The separator is formed of an electrically insulating material and electrically insulates the positive electrode 13A from the negative electrode 13B.

The positive electrode collector 14A is formed from a positive electrode collector foil or the like. A positive electrode active material-containing layer (not shown) is formed on the surface of the positive electrode collector 14A. The positive electrode collector 14A is, for example, an aluminum foil or an aluminum alloy foil. The thickness of the positive electrode collector 14A is about 10 μm to 20 μm. The positive electrode active material-containing layer comprises a positive electrode active material. The positive electrode active material-containing layer may optionally contain a binder and a conductive agent. The positive electrode active material is, for example, an oxide, a sulfide, a polymer, or the like that can absorb and release lithium ions. The positive electrode collector tab 15A is a portion of the positive electrode collector 14A that does not support the positive electrode active material-containing layer (not supported). The positive electrode collector tab 15A protrudes from the negative electrode 13B and the separator.

The negative electrode collector 14B is formed from a negative electrode current collector foil or the like. A negative electrode active material-containing layer (not shown) is formed on the surface of the negative electrode collector 14B. The negative electrode collector 14B is, for example, an aluminum foil, an aluminum alloy foil, or a copper foil. The thickness of the negative electrode collector 14B is about 10 μm to 20 μm. The negative electrode active material-containing layer comprises a negative electrode active material. The negative electrode active material-containing layer may optionally contain a binder and a conductive agent. The negative electrode active material is, for example, a metal oxide, a metal sulfide, a metal nitride, a carbon material, or the like that can absorb and release lithium ions. The negative electrode current collector tab 15B is a portion of the negative electrode collector 14B on which the negative electrode active material-containing layer is not supported (unsupported). The negative electrode current collector tab 15B protrudes from the positive electrode 13A and the separator to the side opposite to the side on which the positive electrode current collector tab 15A protrudes.

In one example of an electrode group 2, a positive electrode 13A, a negative electrode 13B, and a separator are wound around a winding axis W. The positive electrode 13A is offset to one side of the axial direction along the winding axis W relative to the separator. The negative electrode 13B is offset to the opposite side of the axial direction from the positive electrode 13A relative to the separator. Therefore, a pair of current collector tabs 15 (positive electrode current collector tab 15A and negative electrode current collector tab 15B) protrude outward in the axial direction relative to the separator. In this case, the positive electrode current collector tab 15A protrudes to one side in the axial direction relative to the separator. The negative electrode current collector tab 15B protrudes in the opposite direction to the direction in which the positive electrode current collector tab 15A protrudes relative to the separator.

In another example of the electrode group 2, multiple positive electrodes 13A and multiple negative electrodes 13B are alternately stacked. That is, the electrode group 2 has a stack structure. Multiple positive electrodes 13A are offset to one side relative to the separator. Multiple negative electrodes 13B are offset to the opposite side of the separator from the positive electrodes 13A. Therefore, a pair of current collector tabs 15 protrude outward from the separator. Specifically, the positive electrode current collector tab 15A protrudes along the lateral direction of the battery 1 from the separator, and the negative electrode current collector tab 15B protrudes on the opposite side to the positive electrode current collector tab 15A in the lateral direction of the battery 1 from the separator.

In the following description, the electrode group 2 is described as being the wound-type electrode group described above, but the electrode group 2 is not limited to this. As shown in FIG. 1A, one of the pair of current collecting tabs 15 protrudes to one side in the lateral direction of the battery 1 (axial direction along the winding axis W). The other of the pair of current collecting tabs 15 protrudes in the lateral direction of the battery 1 opposite to the direction in which one of the pair of current collecting tabs 15 protrudes. That is, the positive electrode current collecting tab 15A protrudes to one side in the lateral direction of the battery 1, and the negative electrode current collecting tab 15B protrudes to the other side in the lateral direction of the battery 1. Due to the above-mentioned configuration, the pair of current collecting tabs 15 do not come into contact with each other.

A pair of backup leads 16 are attached to the pair of current collector tabs 15 from the lateral outside of the battery 1. One of the pair of backup leads 16 is a positive backup lead 16A, and the other of the pair of backup leads 16 is a negative backup lead 16B. The positive backup lead 16A is attached to the positive current collector tab 15A from the lateral outside. The negative backup lead 16B is attached to the negative current collector tab 15B from the lateral outside. The positive backup lead 16A is bound by sandwiching multiple strip-shaped portions of the positive current collector tab 15A. The negative backup lead 16B is bound by sandwiching the strip-shaped portions of the negative current collector tab 15B.

In the internal cavity 10, the electrode group 2 is held (impregnated) with an electrolyte (not shown). The electrolyte may be a non-aqueous electrolyte in which an electrolyte is dissolved in an organic solvent, or an aqueous electrolyte such as an aqueous solution. Instead of the electrolyte, a gel electrolyte or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte is interposed between the positive electrode 13A and the negative electrode 13B in the electrode group instead of a separator. In this case, the positive electrode 13A is electrically insulated from the negative electrode 13B by the solid electrolyte.

In the battery 1, a pair of electrode terminals 17 are attached to the outer surface of the lid member 6. The pair of electrode terminals 17 are exposed to the outside of the battery 1 and are disposed on the outer surface of the lid member 6. Thus, the pair of electrode terminals 17 are provided on the exterior member 3. The pair of electrode terminals 17 are formed from a conductive material such as metal. One of the pair of electrode terminals 17 is the positive electrode terminal 17A of the battery 1. The other of the pair of electrode terminals 17 other than the positive electrode terminal 17A is the negative electrode terminal 17B of the battery 1. On the outer surface of the lid member 6, an insulating member 18 is provided between each of the pair of electrode terminals 17 and the lid member 6. Each of the pair of electrode terminals 17 is electrically insulated from the exterior container 5 and the lid member 6 by the insulating member 18.

A pair of collector connection plates 30 are arranged in the internal cavity 10 of the outer container 5. One of the pair of collector connection plates 30 is a positive collector connection plate 30A. The other of the pair of collector connection plates 30 other than the positive collector connection plate 30A is a negative collector connection plate 30B. The positive collector connection plate 30A forms at least a part of the electrical path between the positive collector tab 15A and the positive terminal 17A. Therefore, the positive collector tab 15A is electrically connected to the positive terminal 17A through at least the positive collector connection plate 30A. The negative collector connection plate 30B forms at least a part of the electrical path between the negative collector tab 15B and the negative terminal 17B. Therefore, the negative collector tab 15B is electrically connected to the negative terminal 17B through at least the negative collector connection plate 30B. Each of the current collector connection plates 30 is made of a conductive material such as a metal. Examples of materials that form the current collector connection plates 30 include aluminum, stainless steel, copper, iron, etc. The pair of current collector connection plates 30 is, for example, a pair of leads.

In each of the pair of current collecting tabs 15, a plurality of strip-shaped portions are stacked. When manufacturing the battery 1, before electrically connecting each of the current collecting tabs 15 to a corresponding one of the electrode terminals 17, the plurality of strip-shaped portions are bound by the backup lead 16 in each of the pair of current collecting tabs 15. Therefore, in each of the current collecting tabs 15, the plurality of strip-shaped portions bound by the backup lead 16 are electrically connected to a corresponding one of the pair of electrode terminals 17 via a corresponding one of the pair of current collecting connection plates 30. Specifically, the plurality of strip-shaped portions of the positive electrode current collecting tab 15A bound by the positive electrode side backup lead 16A are electrically connected to the positive electrode terminal 17A via the positive electrode side current collecting connection plate 30A. The plurality of strip-shaped portions of the negative electrode current collecting tab 15B bound by the negative electrode side backup lead 16B are electrically connected to the negative electrode terminal 17B via the negative electrode side current collecting connection plate 30B.

In the example of FIG. 1A, a gas release valve 19 and a liquid inlet (not shown) are formed in the lid member 6. Then, a sealing plate 20 that closes the liquid inlet is welded to the outer surface of the lid member 6. Note that the gas release valve 19 and the liquid inlet, etc. do not have to be provided in the battery 1. Also, in the internal cavity 10 of the outer container 5, the pair of current collecting tabs 15 and the pair of current collecting connection plates 30 are electrically insulated from the outer container 5 by one or more insulating members (not shown).

Next, the joint between the pair of current collector tabs 15 and the pair of current collector connection plates 30 will be described. FIG. 1B is a perspective view that shows an example of a current collector connection plate that is joined to the current collector tab of the battery according to the embodiment. FIG. 2 is a cross-sectional view that shows a configuration in the vicinity of the joint between the current collector tab 15 and the current collector connection plate 30 in a cross section perpendicular to the height direction of the battery. In FIG. 1B and FIG. 2, the height direction, lateral direction, and depth direction of the battery 1 are also defined as in FIG. 1A. As shown in FIG. 1B and FIG. 2, in the current collector connection plate 30, the first direction (indicated by the arrows X3 and X4) coincides or approximately coincides with the depth direction of the battery 1. The second direction (indicated by the arrows Y3 and Y4) intersects with the first direction (orthogonal or approximately orthogonal). The third direction (indicated by the arrows Z3 and Z4) intersects with both the first direction and the second direction (orthogonal or approximately orthogonal).

In this embodiment, the second direction coincides or approximately coincides with the lateral direction of the battery 1. The second direction also coincides or approximately coincides with the protruding direction of the current collecting tab 15 protruding from the electrode group 2 and the direction opposite to the protruding direction. The third direction coincides or approximately coincides with the height direction of the battery 1. The joint is formed, for example, at the connection portion between the current collecting tab 15 and the current collecting connection plate 30. As a result, the current collecting tab 15 is joined to the current collecting connection plate 30 and the current collecting tab 15 and the current collecting connection plate 30 are electrically connected. The joint is formed, for example, by a horn (ultrasonic horn) used in ultrasonic bonding.

The pair of collector connection plates 30 each have a substrate portion 31, a protrusion portion 32, and a top plate portion 33. The positive collector connection plate 30A has a positive substrate portion 31A, a positive protrusion portion 32A, and a positive top plate portion 33A. The negative collector connection plate 30B has a negative substrate portion 31B, a negative protrusion portion 32B, and a negative top plate portion 33B. A positive joint portion is formed between the positive collector tab 15A and the positive collector connection plate 30A, and a negative joint portion is formed between the negative collector tab 15B and the negative collector connection plate 30B.

Here, the positive electrode side current collector connection plate 30A is configured in the same manner as the negative electrode side current collector connection plate 30B. The positive electrode side joint is configured in the same manner as the negative electrode side joint. Therefore, the same description of the configuration as the positive electrode side joint also applies to the negative electrode side joint. Therefore, hereinafter, the positive electrode side current collector connection plate 30A is described as the current collector connection plate 30, the positive electrode current collector tab 15A is described as the current collector tab 15, and the positive electrode side joint is described as the joint, and the description of the negative electrode side current collector connection plate 30B, the negative electrode current collector tab 15B, and the negative electrode side joint is omitted. Note that the joint in this embodiment does not have to be formed on both of the pair of current collector tabs 15. That is, the joint may be formed on only one of the pair of current collector tabs 15, or may be formed on both of the pair of current collector tabs 15. In addition, the current collector connection plate 30 in this embodiment does not have to be used for both of the pair of current collector connection plates 30. That is, the current collecting connection plate 30 may be used for only one of the pair of current collecting connection plates 30 , or may be used for both of the pair of current collecting connection plates 30 .

As shown in FIG. 1B, the current collector connection plate 30 includes a substrate portion 31, a protruding portion 32, and a top plate portion 33. The substrate portion 31 and the protruding portion 32 of the current collector connection plate 30 are extended along the height direction of the battery 1, that is, the third direction of the current collector connection plate 30. As shown in FIG. 1B and FIG. 2, the substrate portion 31 includes a joint surface S1, a bottom surface S2, and a pair of side surfaces S3 and S4. The protruding portion 32 includes a protruding end S5 and a pair of side surfaces S6 and S7. The backup lead 16 (current collector tab 15) is joined to the substrate portion 31 from one side in the first direction of the current collector connection plate 30. As described above, the backup lead 16 is attached to the current collector tab 15 from the lateral outer side of the battery 1 to bind the strip-shaped portion of the current collector tab 15. Because of this configuration, when the backup lead 16 is joined to the current collector connection plate 30, the strip-shaped portion of the current collector tab 15 is connected to the current collector connection plate 30 via the backup lead 16. That is, the current collecting tab 15, the backup lead 16, and the current collecting connection plate 30 are electrically connected.

The joint surface S1 forms one end surface of the substrate portion 31 in the first direction of the current collector connection plate 30. The bottom surface S2 forms the end surface of the substrate portion 31 opposite the joint surface S1 in the first direction of the current collector connection plate 30. In this embodiment, the bottom surface S2 forms the end surface of the substrate portion 31 opposite the protruding portion 32 in the first direction of the current collector connection plate 30. In the substrate portion 31, the bottom surface S2 faces the joint surface S1 in the first direction of the current collector connection plate 30. In addition, the pair of side surfaces S3, S4 face each other in the second direction of the current collector connection plate 30. One side surface S3 of the pair of side surfaces is provided on the side where the electrode group 2 is located in the second direction of the current collector connection plate 30. The other side surface S4 of the pair of side surfaces is provided on the distal side of the electrode group 2 from the side surface S3 in the second direction of the current collector connection plate 30. The bottom surface S2 extends from the side surface S3 to the side surface S4 in the second direction of the current collector connection plate 30. The pair of side surfaces S3, S4 extend from the joint surface S1 to the bottom surface S2 in the first direction of the current collector connection plate 30.

The protruding portion 32 protrudes from the joint surface S1 of the substrate portion 31 along the first direction of the current collector connection plate 30. The protruding end S5 forms the tip of the protruding portion 32 in the protruding direction. The protruding end S5 is provided on the opposite side of the bottom surface S2 of the substrate portion 31 in the first direction of the current collector connection plate 30. The pair of side surfaces S6, S7 face each other in the second direction of the current collector connection plate 30. One side surface S6 of the pair of side surfaces is provided on the side where the electrode group 2 is located in the second direction of the current collector connection plate 30. The other side surface S7 of the pair of side surfaces is provided on the distal side of the side surface S6 with respect to the current collector tab 15 in the second direction of the current collector connection plate 30. The protruding end S5 extends from the side surface S6 to the side surface S7 in the second direction of the current collector connection plate 30. The protruding portion 32 does not need to be formed over the entire length in the first direction of the current collector connection plate 30. In other words, it is sufficient that the protrusion 32 is formed at least partially along the first direction of the current collecting connection plate 30 .

The protrusion 32 is provided at a position away from the electrode group 2 in one direction of the second direction of the current collector connection plate 30. In this embodiment, the protrusion 32 is located on the side where the exterior member 3 is located with respect to the joint surface S1 in the second direction of the current collector connection plate 30, and forms the end of the current collector connection plate 30. That is, the protrusion 32 is provided at a position where the side surface S7 of the protrusion 32 is flush with the side surface S4 of the substrate portion 31. Therefore, the side surface S8 of the current collector connection plate 30 is formed by the side surface S7 of the protrusion 32 and the side surface S4 of the substrate portion 31. The side surface S8 of the current collector connection plate 30 is provided on the opposite side to the side surface S3 of the substrate portion 31 in the second direction of the current collector connection plate 30. At this time, the joint surface S1 of the substrate portion 31 is extended along the second direction of the current collector connection plate 30 between the side surface S3 of the substrate portion 31 and the side surface S6 of the protrusion 32.

Since the joint surface S1 of the substrate portion 31 is formed in this manner, the side surface S6 of the protrusion 32 is connected to the joint surface S1 at the end opposite to the end of the joint surface S1 formed by the side surface S3 in the second direction of the current collector connection plate 30. The side surface S6 of the protrusion 32 rises from the end of the joint surface S1 toward the opposite side to the bottom surface S2 in the first direction of the current collector connection plate 30. The side surface S6 of the protrusion 32 extends from the rising portion of the side surface S6 to the protruding end S5 along the first direction of the current collector connection plate 30. The protruding end S5 of the protrusion 32 extends from the side surface S6 of the protrusion 32 to the side surface S8 of the current collector connection plate 30 along the second direction of the current collector connection plate 30. Since the substrate portion 31 and the protrusion 32 are formed in the current collector connection plate 30 as described above, the current collector connection plate 30 is formed in an L-shape or an approximately L-shape in the cross section shown in FIG. 2.

The top plate portion 33 is located on the side where the electrode terminal 17 is located with respect to the joint (joint surface S1) of the current collector tab 15 in the third direction of the current collector connection plate 30. The top plate portion 33 is connected to the end of the substrate portion 31 on the side where the electrode terminal 17 is located in the third direction of the current collector connection plate 30. Therefore, the top plate portion 33 is provided on the side where the electrode terminal 17 is located relative to the current collector tab 15 in the third direction of the current collector connection plate 30. The protruding portion 32 is connected to the top plate portion 33 from the side opposite to the side where the electrode terminal 17 is located in the third direction of the current collector connection plate 30. In other words, the protruding end S5 of the protruding portion 32 is connected to the top plate portion 33.

The backup lead 16 has a pair of flat plate portions 161 and a folded portion 162. The pair of flat plate portions 161 are connected to the folded portion 162 at the end opposite to the edge E (E1, E2). One of the pair of flat plate portions 161 is flat plate portion 161A, and the other of the pair of flat plate portions 161 is flat plate portion 161B. The flat plate portion 161A faces the flat plate portion 161B on one side of the plate thickness direction of the flat plate portion 161A. The flat plate portion 161A extends from the edge E1 to the connection portion with the folded portion 162. The flat plate portion 161B extends from the edge E2 to the connection portion with the folded portion 162. The folded portion 162 folds the flat plate portion 161A back against the flat plate portion 161B. As described above, in this embodiment, the backup lead 16 is attached to the current collecting tab 15 from the lateral outside of the battery 1. Then, the backup lead 16 (current collecting tab 15) is joined to the joining surface S1, whereby the current collecting tab 15, the backup lead 16, and the current collecting connection plate 30 are electrically connected to each other.

Since the backup lead 16 is attached to the current collector tab 15 in this manner, the pair of flat plate portions 161 face each other in the first direction of the current collector connection plate 30. One of the pair of flat plate portions 161 (flat plate portion 161B) is joined to the joining surface S1 from one side of the first direction of the current collector connection plate 30. In addition, the folded portion 162 is arranged on the side where the protruding portion 32 is located with respect to the pair of flat plate portions 161 in the second direction of the current collector connection plate 30. The folded portion 162 contacts the side S6 of the protruding portion 32 from the side where the electrode group 2 is located in the second direction of the current collector connection plate 30. Therefore, the backup lead 16 is not provided at a position beyond the protruding portion 32 in the protruding direction of the current collector tab 15. In other words, the side S6 of the protruding portion 32 restricts the folding portion 162 and the protruding end of the current collector tab 15 from moving to the side where the exterior member 3 is located in the second direction of the current collector connection plate 30. It is sufficient that the folded portion 162 is at least partially in contact with the side surface S6 of the protruding portion 32 from the side where the electrode group 2 is located in the second direction of the current collecting connection plate 30.

It is preferable that the side surface S6 of the protrusion 32 is formed in a shape that follows the shape of the folded portion 162. In the example shown in FIG. 2, the surface of the folded portion 162 on the side where the protrusion 32 is located faces the side surface S6 of the protrusion 32 in the second direction of the current collector connection plate 30. In this case, the side surface S6 of the protrusion 32 is formed in a planar or approximately planar shape. In addition, the side surface S6 of the protrusion 32 is located on the side where the exterior member 3 (exterior container 5) is located, relative to the protruding end of the current collector tab 15, in the second direction of the current collector connection plate 30. The side surface S6 of the protrusion 32 becomes a proximate surface that is close to the protruding end of the current collector tab 15 from the side where the exterior member 3 is located in the second direction of the current collector connection plate 30, with the folded portion 162 of the backup lead 16 interposed therebetween.

Next, the dimensions of the current collector connection plate 30 will be described. In the current collector connection plate 30, dimensions T1, T2, T3, W1, W2, and W3 are defined. Dimensions T1, T2, and T3 are all dimensions along the first direction of the current collector connection plate 30. Dimension T1 is the plate thickness of the substrate portion 31 along the first direction of the current collector connection plate 30. That is, dimension T1 is the dimension between the joint surface S1 and the bottom surface S2 along the first direction of the current collector connection plate 30. Dimension T2 is the amount of protrusion 32 protruding from the substrate portion 31 along the first direction of the current collector connection plate 30. That is, dimension T2 is the dimension between the joint surface S1 and the protruding end S5 along the first direction of the current collector connection plate 30. Dimension T3 is the dimension between the bottom surface S2 and the protruding end S5 along the first direction of the current collector connection plate 30.

Dimensions W1, W2, and W3 are all dimensions along the second direction of the current collector connection plate 30. Dimension W1 is the dimension of the joint surface S1 along the second direction of the current collector connection plate 30. That is, dimension W1 is the dimension between the side surface S3 of the substrate portion 31 and the side surface S6 of the protrusion 32 (the portion where the side surface S6 rises from the joint surface S1) along the second direction of the current collector connection plate 30. Dimension W2 is the dimension of the protrusion 32 along the second direction of the current collector connection plate 30. That is, dimension W2 is the dimension between the pair of side surfaces S6, S7 of the protrusion 32 along the second direction of the current collector connection plate 30. Dimension W3 is the dimension between the pair of side surfaces S3, S4 of the substrate portion 31 along the second direction of the current collector connection plate 30. However, as shown in an example in Figure 2, when the side surface S7 of the protrusion 32 and the side surface S4 of the substrate portion 31 are flush with each other, the dimension W3 coincides or approximately coincides with the dimension between the side surface S3 of the substrate portion 31 and the side surface S8 of the current collecting connection plate 30.

In the current collector connection plate 30, the dimension W1 is greater than the dimension W2. That is, W1>W2. In addition, it is preferable that the dimension W1 is equal to or greater than the dimension of the backup lead 16 in the second direction of the current collector connection plate 30. The dimension of the backup lead 16 in the second direction of the current collector connection plate 30 is the dimension in the second direction of the current collector connection plate 30 between the edge E of the pair of flat plate portions 161 and the end of the folded portion 162 on the side where the protrusion 32 is located. Since the dimension W1 and the dimension of the backup lead 16 in the second direction of the current collector connection plate 30 satisfy such a relationship, when the backup lead 16 is joined to the joining surface S1 of the current collector connection plate 30, the backup lead 16 does not exceed the side surface S3 of the substrate portion 31 on the side where the electrode group 2 is located in the second direction of the current collector connection plate 30.

When the dimension W1 and the dimension of the backup lead 16 in the second direction of the current collector connection plate 30 are the same or approximately the same, the backup lead 16 is joined to the joint surface S1 of the current collector connection plate 30 (substrate portion 31) with the folded portion 162 in contact with the side surface S6 of the protruding portion 32. In this case, the edge E1 of the pair of flat portions 161 of the backup lead 16 is in the same position or almost the same position as the side surface S3 of the substrate portion 31 in the second direction of the current collector connection plate 30. Even when the dimension W1 is larger than the dimension of the backup lead 16 in the second direction of the current collector connection plate 30, the backup lead 16 is joined to the joint surface S1 of the current collector connection plate 30 (substrate portion 31) with the folded portion 162 in contact with the side surface S6 of the protruding portion 32. In this case, edges E1 of a pair of flat plate portions 161 of backup lead 16 are provided on the side where protrusion 32 is located relative to side surface S3 of substrate portion 31 in the second direction of current collector connection plate 30.

As described above, in this embodiment, the current collector connection plate 30 includes a joint surface S1, a substrate portion 31, and a protruding portion 32. The substrate portion 31 is formed with a joint surface S1. The joint surface S1 faces the first direction and is joined to the current collector tab 15. The protruding portion 32 is formed adjacent to the protruding end of the current collector tab 15 in a second direction intersecting the first direction, and protrudes from the substrate portion 31 to the side to which the joint surface S1 faces in the first direction. Since the protruding end of the current collector tab 15 and the protruding portion 32 are arranged in this manner, when the current collector tab 15 is joined to the current collector connection plate 30, the protruding end of the current collector tab 15 is effectively prevented from exceeding the protruding portion 32 in the second direction. Therefore, in the battery 1 of this embodiment, the current collector tab 15 can be joined to an appropriate position of the current collector connection plate 30.

In this embodiment, the protruding portion 32 preferably has a proximity surface. The proximity surface is provided on the side where the exterior member 3 is located in the second direction of the current collecting connection plate 30 from the protruding end of the current collecting tab 15, and is close to the current collecting tab 15 from the side where the exterior member 3 is located in the second direction of the current collecting connection plate 30. The proximity surface also faces the side where the protruding end of the current collecting tab 15 is located. The proximity surface is preferably formed in a shape that follows the shape of the part adjacent to the proximity surface from the side where the proximity surface faces in the second direction of the current collecting connection plate 30. In this embodiment, the side surface S6 of the protruding portion 32 functions as the proximity surface. By forming the proximity surface in this manner, when the current collecting tab 15 is joined to the joining surface S1, the current collecting tab 15 can be positioned proximal to the protruding portion 32 in the second direction. Therefore, for example, when the current collecting tab 15 is connected to the current collecting connection plate 30 by ultrasonic joining, the protruding end of the current collecting tab 15 is effectively prevented from deforming beyond the proximity surface of the protruding portion 32 in the second direction. Furthermore, when joining the current collecting tab 15 to the joining surface S1, the position of the current collecting tab 15 can be easily aligned with a predetermined location on the current collecting connection plate 30. Therefore, in the battery 1 of this embodiment, the current collecting tab 15 can be joined to the current collecting connection plate 30 at an appropriate position.

In the current collector connection plate 30 of this embodiment, it is preferable that the dimension T3 in the first direction between the protruding end S5 of the protruding portion 32 and the bottom surface S2 of the substrate portion 31 is larger than the dimension T1 in the first direction between the joint surface S1 and the bottom surface S2 of the substrate portion 31. By forming the protruding portion 32 in this manner, the cross-sectional area of the current collector connection plate 30 is increased in the cross section (cross section perpendicular or substantially perpendicular to the third direction of the current collector connection plate 30) shown in the example of FIG. 2. Therefore, the heat generated by the current flowing through the current collector connection plate 30 is reduced. Therefore, the temperature rise of the current collector connection plate 30 caused by the generation of this heat is suppressed. In addition, the rigidity of the current collector connection plate 30 is improved by forming the protruding portion 32 on the current collector connection plate 30. Therefore, deformation of the current collector connection plate 30 is suppressed.

In the current collector connection plate 30 of this embodiment, it is preferable that the dimension W2 in the second direction of the protrusion 32 is smaller than the dimension W1 in the second direction between the portion where the side surface S6 of the protrusion 32 as the adjacent surface rises from the joining surface S1 and the end of the substrate portion 31 on the opposite side to the side on which the protrusion 32 is formed in the second direction. By forming the protrusion 32 in this manner, for example, it is possible to secure an area to which the current collector tab 15 is joined while keeping the dimension W3 of the current collector connection plate 30 at a predetermined size or less.

In this embodiment, the protrusion 32 preferably forms the end of the current collector connection plate 30 on the exterior member 3 side in the second direction. By forming the protrusion 32 in this manner, for example, the joint surface S1, which is the portion to be joined with the current collector tab 15, can be sufficiently secured. Therefore, when aligning the position of the current collector tab 15 with a predetermined portion of the current collector connection plate 30, the degree of freedom in arranging the current collector tab 15 is increased. Therefore, in the battery 1 of this embodiment, the current collector tab 15 can be joined to an appropriate position on the current collector connection plate 30.

(Modification)
Figure 3 is a cross-sectional view that shows a modified example of the configuration in the vicinity of the joint between the current collecting tab 15 and the current collecting connection plate 30, in a cross section perpendicular to the height direction of the battery 1. In Figure 3, as in Figures 1A, 1B, and 2, the height direction, lateral direction, and depth direction of the battery 1, and the first direction, second direction, and third direction of the current collecting connection plate 30 are defined.

In the modified example shown in FIG. 3, the backup lead 16 is not attached to the current collector tab 15 of the battery 1. That is, the bundled strip of the current collector tab 15 is directly joined to the joint surface S1 of the current collector connection plate 30. When the backup lead 16 is not attached to the current collector tab 15 in this manner, the current collector tab 15 is pressed from one side of the current collector connection plate 30 in the first direction, thereby joining the current collector tab 15 to the current collector connection plate 30. In this modified example, the protruding end of the current collector tab 15 contacts the side surface S6 of the protruding portion 32 as the adjacent surface from the side where the side surface S3 of the current collector connection plate 30 is located. Therefore, as in the above-mentioned embodiment, the current collector tab 15 is not provided at a position beyond the protruding portion 32 in the second direction of the current collector connection plate 30.

In addition, in the case where the backup lead 16 is not provided in this manner, it is preferable that the dimension T2 of the protrusion 32 is larger than the dimension between the joint surface S1 of the current collector connection plate 30 and the surface opposite to the surface joined to the joint surface S1 of the current collector tab 15. That is, the protruding end S5 of the protrusion 32 is disposed distally from the joint surface S1 (substrate portion 31) in the first direction of the current collector connection plate 30, relative to the surface opposite to the surface joined to the joint surface S1 of the current collector tab 15. Therefore, when the current collector tab 15 is joined to the current collector connection plate 30, if the current collector tab 15 is deformed toward the side where the protrusion 32 is located in the second direction of the current collector connection plate 30, the protruding end of the current collector tab 15 comes into contact with the side surface S6 of the protrusion 32. Therefore, the current collector tab 15 is effectively restricted from being provided at a position beyond the protrusion 32 in the second direction of the current collector connection plate 30. Furthermore, since the protruding end of the current collecting tab 15 abuts against the side surface S6 of the protruding portion 32, the position of the current collecting tab 15 can be easily aligned with a predetermined position of the current collecting connection plate 30.

Figure 4 is a cross-sectional view showing a schematic cross section perpendicular to the height direction of the battery of another modified example of the configuration in the vicinity of the joint between the current collector tab 15 and the current collector connection plate 30, different from that shown in Figure 3. In Figure 4, the height direction, lateral direction, and depth direction of the battery 1, and the first direction, second direction, and third direction of the current collector connection plate 30 are specified, as in Figures 1A to 3. In the modified example shown in Figure 4, the side surface S6 of the protrusion 32 is inclined with respect to the joint surface S1. The side surface S6 of the protrusion 32 is formed in such a way that the closer to the protruding end S5 in the first direction of the current collector connection plate 30, the more it faces the side surface S7 of the protrusion 32 in the second direction of the current collector connection plate 30. By forming the side surface S6 of the protrusion 32 in this way, the side surface S6 can be made to conform to the shape of the protruding end of the bundled strip-shaped portion of the current collector tab 15. 4 , when the strip-shaped portion of the current collecting tab 15 is bound, the strip-shaped portion of the current collecting tab 15 may be formed in a tapered or approximately tapered shape in which the thickness of the strip-shaped portion decreases toward the protruding end of the current collecting tab 15 when viewed from one side of the third direction of the current collecting connection plate 30. In such a case, in this modified example, since the side surface S6 of the protruding portion 32 is inclined as described above, the position of the current collecting tab 15 can be easily aligned with a predetermined location on the current collecting connection plate 30.

When the protrusion 32 is formed in this manner, the dimensions T1, T2, T3, W1, W2, and W3 are defined in the same manner as in the previously described embodiment. Therefore, the same relationships regarding dimensions as in the previously described embodiment also apply to this modified example.

The shape of the protrusion 32 is not limited to the shapes of the above-mentioned embodiments and modified examples, and can be appropriately set according to the shape of the current collector connection plate 30 and the shape of the strip portion of the current collector tab 15 (the shape of the protruding end of the current collector tab 15), etc. In one example, the side surface S7 of the protrusion 32 may be inclined with respect to the joint surface S1. That is, the side surface S7 of the protrusion 32 may be formed in a state in which the closer to the protruding end S5 in the first direction of the current collector connection plate 30, the more the side surface S7 of the protrusion 32 faces the side where the current collector tab 15 is located in the second direction of the current collector connection plate 30. In another example, the protrusion 32 may be formed in a shape in which the dimension along the second direction of the current collector connection plate 30 becomes smaller as it faces the protruding end S5 in the first direction of the current collector connection plate 30. That is, the protrusion 32 may be formed in a tapered shape that becomes thinner toward the protruding surface of the protrusion 32 in the first direction of the current collector connection plate 30 when viewed from one side of the third direction of the current collector connection plate 30.

Figure 5 is a cross-sectional view showing a modified example of the battery 1 according to the embodiment, in a cross section perpendicular to the depth direction of the battery 1. Figure 6 is a cross-sectional view showing a modified example of the battery 1 according to the embodiment, in a cross section perpendicular to the width direction of the battery 1. In the battery 1 shown in Figures 5 and 6, the height direction, width direction, and depth direction of the battery 1 are also specified. However, in the battery 1 of this modified example, in the current collector connection plate 30, the first direction (indicated by arrows Z5 and Z6) coincides or approximately coincides with the height direction of the battery 1. The second direction (indicated by arrows X5 and X6) coincides or approximately coincides with the depth direction of the battery 1. The third direction (indicated by arrows Y5 and Y6) coincides or approximately coincides with the width direction of the battery 1.

In the battery 1 of this modified example, the pair of current collecting tabs 15 protrude on the same side relative to each other. The pair of current collecting tabs 15 protrude from the electrode group 2 on the side where the pair of electrode terminals 17 are located in the height direction of the battery 1. In this modified example, the pair of current collecting tabs 15 do not contact each other. Specifically, the positive electrode current collecting tab 15A protrudes from the electrode group 2 on the side where the positive electrode terminal 17A is located. The negative electrode current collecting tab 15B protrudes from the electrode group 2 on the side where the negative electrode terminal 17B is located. In this case, as shown in Figures 5 and 6, in the same manner as in any of the above-mentioned embodiments, the protruding portion 32 of the current collecting connection plate 30 is formed close to the protruding end of the current collecting tab 15 in the second direction and protrudes from the substrate portion 31 to the side where the joint surface S1 faces in the first direction. As a result, the battery 1 of this modified example also has the same effect as the above-mentioned embodiment.

According to at least one of these embodiments, the current collecting connection plate that electrically connects the electrode terminal and the current collecting tab includes a substrate portion and a protruding portion. The substrate portion includes a joint surface that is joined to the current collecting tab, and the joint surface faces one side in the first direction. The protruding portion is formed adjacent to the protruding end of the current collecting tab in a second direction that intersects with the first direction, and protrudes from the substrate portion to the side toward which the joint surface faces in the first direction. This allows the current collecting tab to be joined to an appropriate position on the current collecting connection plate in the battery of the embodiment.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.
The following are additional notes.
[1] An exterior member;
an electrode terminal provided on the exterior member;
an electrode group housed in an internal cavity of the exterior member and having a protruding current collecting tab;
a current collecting connection plate that electrically connects the electrode terminal and the current collecting tab;
Equipped with
The current collecting connection plate is
a substrate portion including a joining surface to be joined to the current collecting tab, the joining surface facing one side in a first direction;
a protruding portion formed adjacent to the protruding end of the current collecting tab in a second direction intersecting the first direction and protruding from the substrate portion toward a side toward which the joining surface faces in the first direction;
Equipped with a battery.
[2] The protruding portion is closer to the current collecting tab from a side on which the exterior member is located in the second direction than the protruding end of the current collecting tab, and has an adjacent surface facing the side on which the protruding end of the current collecting tab is located.
The battery according to [1].
[3] The substrate portion includes a bottom surface provided on an opposite side to a side on which the protrusion is located in the first direction,
In the current collecting connection plate, a dimension in the first direction between a tip of the protrusion and the bottom surface of the base portion is larger than a dimension in the first direction between the joint surface and the bottom surface.
The battery according to [2].
[4] In the current collecting connection plate, a dimension in the second direction of the protruding portion is smaller than a dimension in the second direction between a portion where the adjacent surface rises from the joining surface and an end of the substrate portion on the opposite side to the side on which the protruding portion is formed in the second direction.
The battery according to [2] or [3].
[5] The protrusion forms an end of the current collector connection plate on the exterior member side in the second direction.
The battery according to any one of [1] to [4].
[6] The electrode terminal is provided on one side of the electrode group in a third direction intersecting both the first direction and the second direction.
The battery according to any one of [1] to [5].
[7] The current collecting connection plate is located on a side of the joint surface on which the electrode terminal is located in the third direction, and includes a top plate portion to which the electrode terminal is connected,
the protruding portion is connected to the top plate portion from a side opposite to a side on which the electrode terminal is located in the third direction.
The battery according to [6].
[8] The current collecting tabs include a positive electrode current collecting tab that protrudes from the electrode group, and a negative electrode current collecting tab that protrudes from the electrode group without contacting the positive electrode current collecting tab,
At least one of the current collector connection plate, the joint surface of which is joined to the positive electrode current collector tab, and the current collector connection plate, the joint surface of which is joined to the negative electrode current collector tab, is provided.
The battery according to any one of [1] to [7].

Claims (7)

An exterior member;
an electrode terminal provided on the exterior member;
an electrode group housed in an internal cavity of the exterior member and having a protruding current collecting tab;
a current collecting connection plate that electrically connects the electrode terminal and the current collecting tab;
Equipped with
The current collecting connection plate is
a substrate portion including a joining surface to be joined to the current collecting tab, the joining surface facing one side in a first direction;
a protruding portion formed adjacent to the protruding end of the current collecting tab in a second direction intersecting the first direction and protruding from the substrate portion toward a side toward which the joining surface faces in the first direction;
Equipped with
the protruding portion is closer to the current collecting tab from a side on which the exterior member is located in the second direction than the protruding end of the current collecting tab, and has a proximate surface facing the side on which the protruding end of the current collecting tab is located,
The adjacent surface extends along the first direction to a protruding end of the protruding portion,
The protruding end of the protruding portion extends along the second direction from the adjacent surface to an end of the current collecting connection plate.
battery. the base portion includes a bottom surface provided on a side opposite to a side on which the protrusion is located in the first direction,
In the current collecting connection plate, a dimension in the first direction between the protruding end of the protruding portion and the bottom surface of the substrate portion is larger than a dimension in the first direction between the joint surface and the bottom surface.
10. The battery of claim 1 . In the current collecting connection plate, a dimension in the second direction of the protruding portion is smaller than a dimension in the second direction between a portion where the adjacent surface rises from the joint surface and an end of the substrate portion on an opposite side to a side on which the protruding portion is formed in the second direction.
The battery according to claim 1 or 2 . The protrusion forms an end of the current collector connection plate on the exterior member side in the second direction.
The battery according to any one of claims 1 to 3 . the electrode terminal is provided on one side of the electrode group in a third direction intersecting both the first direction and the second direction;
The battery according to any one of claims 1 to 4 . the current collecting connection plate is located on a side of the joint surface on which the electrode terminal is located in the third direction, and includes a top plate portion to which the electrode terminal is connected,
the protruding portion is connected to the top plate portion from a side opposite to a side on which the electrode terminal is located in the third direction.
6. The battery of claim 5 . the current collecting tabs include a positive electrode current collecting tab that protrudes from the electrode group, and a negative electrode current collecting tab that protrudes from the electrode group without contacting the positive electrode current collecting tab,
At least one of the current collector connection plate, the joint surface of which is joined to the positive electrode current collector tab, and the current collector connection plate, the joint surface of which is joined to the negative electrode current collector tab, is provided.
The battery according to any one of claims 1 to 6 .

Images