Patent ID: 12230841

DETAILED DESCRIPTION

According to an embodiment, a battery includes an exterior container, a lid member, a plurality of electrode groups, a first current collecting tab, a second current collecting tab, first lead, a second lead, and an electrode terminal. The exterior container includes a bottom wall and a peripheral wall, and an inner cavity, open toward a side opposite the bottom wall in the height direction, is formed in the exterior container. The lid member is attached to the peripheral wall of the exterior container in such a manner that it closes the opening of the inner cavity. Each of the electrode groups includes a positive electrode and a negative electrode, and the plurality of electrode groups are stored in the inner cavity of the exterior container. In a first electrode group, which is one of the electrode groups, the first current collecting tab protrudes toward the side where the lid member is located, and in a second electrode group, which is another electrode group among the electrode groups, the second current collecting tab protrudes toward the side where the lid member is located. The first current collecting tab is joined with the first lead. The second lead is formed to be separate from the first lead, and the second current collecting tab is joined with the second lead. The electrode terminal is exposed on the outer surface of the lid member, and the first lead and the second lead are together connected to the electrode terminal.

Hereinafter, the embodiments will be described with reference to the accompanying drawings.

First Embodiment

FIGS.1and2show a battery1according to the first embodiment. As shown inFIGS.1and2, the battery1includes a plurality of electrode groups2A and2B, an exterior container3, and a lid member5. Each of the exterior container3and the lid member5is formed of a metal such as aluminum, an aluminum alloy, iron, copper, or stainless steel. Herein, in the battery1(exterior container3), a depth direction (the direction indicated by arrows X1and X2), a lateral direction intersecting (orthogonal or approximately orthogonal to) the depth direction (the direction indicated by arrows Y1and Y2), a height direction intersecting (orthogonal or approximately orthogonal to) the depth direction and the lateral direction (the direction indicated by arrows Z1and Z2) are defined. The battery1and the container3each have a smaller dimension in the depth direction than both the dimension in the lateral direction and the dimension in the height direction.FIG.1is a perspective view of the battery1, andFIG.2an exploded perspective view of the battery1.

The exterior container3includes a bottom wall6and a peripheral wall7. In the inside of the exterior container3, an inner cavity8in which the electrode groups2are housed is defined by the bottom wall6and the peripheral wall7. In the exterior container3, the inner cavity8is open toward the side opposite a side at which the bottom wall6is positioned in the height direction. The peripheral wall7includes two pairs of side walls, side walls11and side walls12. The side walls11that form one pair face each other with the inner cavity8intervening therebetween in the lateral direction. The side walls12, which constitute a pair, face each other with the inner cavity8intervening therebetween in the depth direction. Each of the side walls11continuously extends in the depth direction between the side walls12. Each of the side walls12continuously extends in the lateral direction between the side walls11. The lid member5is attached to the peripheral wall7at an end opposite the bottom wall6. Therefore, the lid member5covers an opening of the inner cavity8of the exterior container3. The lid member5and the bottom wall6face each other with the inner cavity8intervening therebetween in the height direction.

In the example shown inFIG.1, etc., two electrode groups2A and2B are arranged in the inner cavity8. In the inner cavity8, a plurality of (two) electrode groups2A and2B are arranged side by side according to the depth direction. The electrode group (first electrode group)2A is arranged adjacently to the electrode group (second electrode group)2B in the depth direction. Each of the electrode groups2A and2B includes a positive electrode15and a negative electrode16. In each of the electrode groups2A and2B, a separator (not shown) intervenes between the positive electrode15and the negative electrode16. In each of the electrode groups2A and2B, the separator is made of a material having electrical insulation properties, and electrically insulates the positive electrode15from the negative electrode16. The electrode group2A includes a pair of current collecting tabs (first current collecting tabs)17A, and the electrode group2B includes a pair of current collecting tabs (second current collecting tabs)17E.

In each of the electrode groups2A and2B, the positive electrode15includes a positive electrode current collector, such as a positive electrode current collecting foil, and a positive electrode active material-containing layer (not shown) supported on the surface of the positive electrode current collector. The positive electrode current collector is, but not limited to, for example, an aluminum foil or an aluminum alloy foil, which has a thickness of about 5 μm to 20 μm. The positive electrode active material-containing layer includes a positive electrode active material, and may optionally contain a binder and an electro-conductive agent. The positive electrode active material is, but not limited to, for example, oxides, sulfides, and polymers, which can occlude and release lithium ions. In the electrode group2A, the part not supporting the positive electrode active material-containing layer in the positive current collector serves as a positive electrode current collecting tab (a first positive electrode current collecting tab) that constitutes one of the pair of current collecting tabs17A. In the electrode group2B, the part not supporting the positive electrode active material-containing layer in the positive current collector serves as a positive electrode current collecting tab (a second positive electrode current collecting tab) that constitutes one of the pair of current collecting tabs17B.

In each of the electrode groups2A and2B, the negative electrode16includes a negative electrode current collector, such as a negative electrode current collecting foil, and a negative electrode active material-containing layer (not shown) supported on the surface of the negative electrode current collector. The negative electrode current collector is, but not limited to, for example, an aluminum foil, an aluminum alloy foil, or a copper foil, having a thickness of about 5 μm to 20 μm. The negative electrode active material containing layer includes a negative electrode active material and may contain a binder and a conductive agent as appropriate. The negative electrode active material is for example, although not limited thereto, a metal oxide, a metal sulfide, a metal nitride, or a carbon material that can occlude and release lithium ions. In the electrode group2A, the part not supporting the negative electrode active material-containing layer in the negative current collector serves as a negative electrode current collecting tab (a first negative electrode current collecting tab) that constitutes another one of the pair of current collecting tabs17A different from the positive electrode current collecting tab. In the electrode group2B, the part not supporting the negative electrode active material-containing layer in the negative current collector serves as a negative electrode current collecting tab (a second negative electrode current collecting tab) that constitutes another one of the pair of current collecting tabs17B different from the positive electrode current collecting tab.

In each of the electrode groups2A and2B, a length direction (a direction indicated by arrows Z3and Z4), a width direction (a direction indicated by arrows Y3and Y4) intersecting (orthogonal to or substantially orthogonal to) the length direction, and a thickness direction (a direction indicated by arrows X3and X4) intersecting (orthogonal to or substantially orthogonal to) both the length direction and the width direction. In each of the electrode groups2A and2B, the dimension in the thickness direction is smaller than both the dimension in the length direction and the dimension in the width direction. Each of the electrode groups2A and2B is formed in a flat shape.

In the electrode group2A, the pair of current collecting tabs (positive electrode current collecting tab and a negative electrode current collecting tab)17A protrudes from one side of the length direction with respect to the positive electrode active material-containing layer, the negative electrode active material-containing layer, and the separator, and the pair of current collecting tabs17A protrudes from the same side in the length direction. Furthermore, in the electrode group2A, the current collecting tabs17A constituting the pair are formed separate from each other in the width direction. In the electrode group2B, the pair of current collecting tabs (positive electrode current collecting tab and a negative electrode current collecting tab)17B protrudes from one side of the length direction with respect to the positive electrode active material-containing layer, the negative electrode active material-containing layer, and the separator, and the pair of current collecting tabs17B protrudes from the same side in the length direction. In the electrode group2B, the current collecting tabs17B constituting a pair are arranged separately from each other in the width direction.

In one example, in each of the electrode groups2A and2B, the positive electrode15, the negative electrode16, and the separator are wound around the winding axis, with the separator being interposed between the positive electrode active material containing layer and the negative electrode active material containing layer, and each of the electrode groups2A and2B having a winding structure. In another example, each of the electrode groups2A and2B has a stack structure in which a plurality of positive electrodes15and a plurality of negative electrodes16are alternately laminated, with the separator interposed therebetween. In the electrode group2A, a plurality of band-shaped portions are bundled at each of the current collecting tabs17A constituting a pair; in the electrode group2B, a plurality of band-shaped portions are bundled at each of the current collecting tabs17B constituting a pair.

In the present embodiment, each of the electrode groups2A and2B is arranged in the inner cavity8in such a manner that the length direction corresponds, or approximately corresponds, to the height direction of the battery1. Furthermore, in each of the electrode groups2A and2B, the width direction corresponds, or approximately corresponds, to the lateral direction of the battery1, and the thickness direction corresponds, or approximately corresponds, to the depth direction of the battery1. The electrode group2A is arranged in the inner cavity8in such a manner that a pair of current collecting tabs17A protrudes toward the side where the lid member5is located in the height direction of the battery1, and the electrode group2B is arranged in the inner cavity8in such a manner that a pair of current collecting tabs17B protrudes toward the side where the lid member5is located in the height direction of the battery1. In the electrode group2A, the current collecting tabs17A constituting a pair are arranged to be separate from each other in the lateral direction of the battery1, and the positive electrode current collecting tab (one of the tabs17A) is not in contact with the negative electrode current collecting tab (the other of the tabs17A). In the electrode group2B, the current collecting tabs17B constituting a pair are arranged to be separate from each other in the lateral direction of the battery1, and the positive electrode current collecting tab (one of the tabs17B) is not in contact with the negative electrode current collecting tab (the other of the tabs17B).

In the inner cavity8, each of the electrode group2A and2B holds (is impregnated with) an electrolytic solution (not shown). The electrolytic solution may be a nonaqueous electrolytic solution obtained by dissolving an electrolyte in an organic solvent, or an aqueous electrolytic solution such as an aqueous solution. Instead of the electrolytic solution, either a gel electrolyte or a solid electrolyte may be used. In the case where a solid electrolyte is used as an electrolyte, the solid electrolyte instead of the separator intervenes between the positive electrode15and the negative electrode16in each of the electrode groups2A and2B. In such a case, in each of the electrode groups2A and2B, the positive electrode15is electrically insulated from the negative electrode16by the solid electrolyte.

In the battery1, a pair of terminals21are attached to the lid member5. The electrode terminals21are made of an electro-conductive material such as a metal. One of the electrode terminals21constituting a pair is a positive electrode terminal of the battery1, and the other terminal21different from the positive electrode terminal is a negative electrode terminal of the battery1. Each of the electrode terminals21is arranged on the outer surface of the lid member5, being exposed to the outside of the battery1. Furthermore, the terminals21in a pair are arranged to be separate from each other in the lateral direction of the battery1. On the outer surface of the lid member5, an insulating member22is provided between each terminal21and the lid member5. Each of the electrode terminals21is electrically insulated from the lid member5and the exterior container3by the insulating member22, etc.

Two pairs of leads23A and23B and two pairs of clip plates25A and25B are arranged in the inner cavity8of the exterior container3. Each of the leads23A and23B and the clip plates25A and25B are made of an electrically conductive material such as a metal, for example aluminum, stainless steel, copper, or iron, etc. The leads23A and23B and the clip plates25A and25B are formed in separate bodies. In the inner cavity8, the leads23A and232and the clip plates25A and25B are arranged between each of the electrode groups2A and2B and the lid member5in the height direction of the battery1.

Each of the current collecting tabs (first current collecting tabs)17A in a pair in the electrode group2A is joined with the corresponding one of the leads (first leads)23A in a pair, with the corresponding one of the clip plates (first clip plates)25A in a pair being interposed therebetween. Herein, one of the leads23A is a positive electrode-side lead (first positive electrode-side lead), and the other different from the positive electrode-side lead is a negative electrode-side lead (first negative electrode-side lead). One of the clip plates25A is a positive electrode-side clip plate (first positive electrode-side clip plate), and the other different from the positive electrode-side clip plate is a negative electrode-side clip plate (first negative electrode-side clip plate).

Each of the leads23A in a pair is connected to the corresponding one of the electrode terminals21in a pair. For this reason, the positive electrode current collecting tab (one of the tabs17A) of the electrode group2A is electrically connected to the positive electrode terminal (one of the terminals21), with the positive electrode-side clip plate (one of the clip plates25A) and the positive electrode-side lead (one of the leads23A) being interposed therebetween, in this order. The negative electrode current collecting tab (the other of the tabs17A different from the positive electrode current collecting tab) of the electrode group2A is electrically connected to the negative electrode terminal (the other of the terminals21different from the positive electrode terminal), with the negative electrode-side clip plate (the other of the clip plates25A different from the positive electrode-side clip plate) and the negative electrode-side lead (the other of the leads23A different from the positive electrode-side lead) being interposed therebetween, in this order.

With the above-described structure, at least a part of an electric path between the positive electrode current collecting tab (one of the tabs17A) of the electrode group2A and the positive electrode terminal (one of the terminals21) is constituted by the positive electrode-side clip plate (one of the clip plates25A) and the positive electrode-side lead (one of the leads23A). At least a part of an electric path between the negative electrode current collecting tab (the other of the tabs17A) of the electrode group2A and the negative electrode terminal (the other of the terminals21) is constituted by the negative electrode-side clip plate (the other of the clip plates25A) and the negative electrode-side lead (the other of the leads23A).

A member constituting the electric path between the positive electrode current collecting tab (one of the tabs17A) of the electrode group2A and the positive electrode terminal (one of the terminals21), such as the positive electrode-side lead (one of the leads23A), is arranged to be separate from a member constituting the electric path between the negative electrode current collecting tab (the other of the tabs17A) of the electrode group2A and the negative electrode terminal (the other of the terminals21), such as the positive electrode-side lead (the other of the leads23A), according to the lateral direction of the battery1. Thus, the member constituting the electric path between the positive electrode current collecting tab (one of the tabs17A) of the electrode2A and the positive electrode terminal (one of the terminals21) is not in contact with the member constituting the electric path between the negative electrode current collecting tab (the other of the tabs17A) of the electrode group2A and the negative electrode terminal (the other of the terminals21).

Each of the current collecting tabs (second current collecting tabs)17B as a pair in the electrode group2B is joined with the corresponding one of the leads (second leads)23B as a pair, with the corresponding one of the clip plates (second clip plates)25B as a pair being interposed therebetween. Herein, one of the leads23B is a positive electrode-side lead (second positive electrode-side lead), and the other different from the positive electrode-side lead is a negative electrode-side lead (second negative electrode-side lead). One of the clip plates25B is a positive electrode-side clip plate (second positive electrode-side clip plate), and the other different from the positive electrode-side clip plate is a negative electrode-side clip plate (second negative electrode-side clip plate).

Each of the leads23B in a pair is connected to the corresponding one of the electrode terminals21in a pair. For this reason, the positive electrode current collecting tab (one of the tabs17B) of the electrode group2B is electrically connected to the positive electrode terminal (one of the terminals21), with the positive electrode-side clip plate (one of the clip plates25B) and the positive electrode-side lead (one of the leads23B) being interposed therebetween, in this order. The negative electrode current collecting tab (the other of the tabs17D different from the positive electrode current collecting tab) of the electrode group2B is electrically connected to the negative electrode terminal (the other of the terminals21different from the positive electrode terminal), with the negative electrode-side clip plate (the other of the clip plates25B different from the positive electrode-side clip plate) and the negative electrode-side lead (the other of the leads23B different from the positive electrode-side clip plate) being interposed therebetween, in this order.

With the above-described structure, at least a part of an electric path between the positive electrode current collecting tab (one of the tabs17B) of the electrode group2B and the positive electrode terminal (one of the terminals21) is constituted by the positive electrode-side clip plate (one of the clip plates25B) and the positive electrode-side lead (one of the leads23B). At least a part of an electric path between the negative electrode current collecting tab (the other of the tabs17B) of the electrode group2B and the negative electrode terminal (the other of the terminals21) is constituted by the negative electrode-side clip plate (the other of the clip plates25B) and the negative electrode-side lead (the other of the leads23B).

A member constituting the electric path between the positive electrode current collecting tab (one of the tabs17B) of the electrode group2B and the positive electrode terminal (one of the terminals21), such as the positive electrode-side lead (one of the leads23B), is arranged to be separate from a member constituting the electric path between the negative electrode current collecting tab (the other of the tabs17B) of the electrode group2B and the negative electrode terminal (the other of the terminals21), such as the negative electrode lead electrode-side lead (the other of the leads23B), according to the lateral direction of the battery1. Thus, the member constituting the electric path between the positive electrode current collecting tab (one of the tabs17B) of the electrode group2B and the positive electrode terminal (one of the terminals21) is not in contact with the member constituting the electric path between the negative electrode current collecting tab (the other of the tabs17B) of the electrode group2B and the negative electrode terminal (the other of the terminals21).

In the battery1of the present embodiment, as described above, electrical connection structures of the electrode groups2A and2B to each pair of the electrode terminals21are formed, and a pair of electrical connection structures is thereby formed. To each of the electrode terminals21in a pair, the corresponding one of the leads (first leads)23A in a pair and corresponding one of the leads (second leads)23B in a pair are connected in conjunction. In other words, in each of the electrical connection structures in a pair, two (multiple) leads23A and23B are connected in conjunction to the electrode terminal21. For example, two positive electrode-side leads (one of the leads23A and one of the leads23B) are connected to the positive electrode terminal, which is one of the electrode terminals21in a pair, and two negative electrode-side leads (the other of the leads23A and the other of the leads23B) are connected to the negative electrode terminal, which is the other of the electrode terminals21in a pair.

A spacer28is housed in the inner cavity8of the exterior container3. The spacer28is made of an electrically insulating material. The spacer28is arranged between each of the electrode groups2A and2B and the lid member5in the height direction of the battery1. In the inner cavity8, the spacer28, etc. prevent two pairs of the current collecting tabs17A and17B, two pairs of leads23A and23B and two pairs of clip plates25A and25B from being in contact with the exterior container3and the lid member5. For this reason, the current collecting tabs17A and17B, the leads23A and23B, the clip plates25A and25B are electrically insulated from the exterior container3and the lid member5. The spacer28presses the electrode groups2A and2B against the side where the bottom wall6is located in the height direction of the battery1. Thus, in the inner cavity8, the movement of each of the electrode groups2A and2B along the height direction of the battery1is restricted.

In one example illustrated inFIGS.1and2, etc., the lid member5is provided with a safety valve31and a liquid inlet (not shown). On the outer surface of the lid member5, a sealing plate32to seal the liquid inlet is welded. The safety valve31and the liquid inlet are arranged between the electrode terminals21constituting a pair in the lateral direction of the battery1. In one example, the battery1may not be provided with the safety valve31and the liquid inlet.

In the following, the electrical connection structure of the electrode groups2A and2B to each of the electrode terminals21in a pair, namely, the above-described pair of electrical connection structures, is described.FIGS.3to5show an electrical connection structure of a plurality of electrode groups2A and2B to one of the electrode terminals21in a pair and the vicinity of the structure, and show one of the electrical connection structures in a pair and the vicinity of the structure.FIG.3is a perspective view showing a state in which the leads23A and23B are not connected to the electrode terminals21.FIG.4shows the battery1viewed from one side of the depth direction, andFIG.5shows the battery1viewed from one side of the lateral direction.

FIG.6shows one of the leads (first leads)23A in a pair and one of the leads (second leads)23B in a pair.FIGS.3to5show only the electrical connection structure of the electrode groups2A and2B to one of the electrode terminals21in a pair; however, the electrical connection structure of the electrode groups2A and2B to the other of the electrode terminals21is the same as that shown inFIGS.3to5.FIGS.3to6show one of the leads23A in a pair and one of the leads23B in a pair; however, the structures of the other lead23A and the other lead23B are the same as those shown inFIGS.3to6.

As shown inFIGS.3to5, in each of the electrical connection structure in a pair, the clip plate25A is attached to the protruding end of the current collecting tab17A and the vicinity thereof, and the clip plate25B is attached to the protruding end of the current collecting tab17B and the vicinity thereof. Each pair of the clip plates25A sandwiches bundled multiple band-shaped portions in the corresponding one of the current collecting tabs17A in a pair, and each pair of the clip plates25B sandwiches bundled multiple band-shaped portions in the corresponding one of the current collecting tabs17B in a pair. In each pair of electrical connection structures, the current collecting tabs17A and17B are arranged in a shifted layout in the lateral direction of the battery1, and the current collecting tabs17A and17B are not in contact with each other.

As shown inFIG.6, etc., in each of the pairs of leads (first leads)23A and each of the pairs of leads (second leads)23B, a length direction (a direction indicated by arrows Y5and Y6), a width direction (a direction indicated by arrows X5and X6) intersecting (orthogonal to or substantially orthogonal to) the length direction, and a height direction (a direction indicated by arrows Z5and Z6) intersecting (orthogonal to or substantially orthogonal to) both the length direction and the width direction are all defined. Each of the leads23A and23B includes a lead base part33, a lead protruding part35, and a lead bent part36.

In each of the leads23A and23B, the lead base part33is formed in the shape of a plate, and the direction of the plate thickness of the lead base part33corresponds, or approximately corresponds, to the height direction. The lead base part33of each of the leads23A and23B includes a pair of base part main surfaces37and38. In each of the leads23A and23B, the base part main surface (first base part main surface)37faces one side of the height direction, and the base part main surface (second base part main surface)38faces the opposite side of the side faced by the base part main surface37according to the height direction.

In each of the leads23A and23B, the lead base part33includes base part edge surfaces41,42,45, and46. In each of the leads23A and23B, the base part edge surface (first base part edge surface)41constitutes the edge of the one side of the width direction in the lead base part33, and the base part edge surface (second base part edge surface)42constitutes the edge of the other side of the width direction which is opposite the base part edge surface41in the lead base part33. Furthermore, in each of the leads23A and23B, each of the base part main surface37and38extends along the width direction in the lead base part33, from the base part edge surface41to the base part edge surface42.

In each of the leads23A and23B, the base part edge surface45constitutes the edge of the one side of the length direction in the lead base part33, and the base part edge surface46constitutes the edge of the other side of the length direction which is opposite the base part edge surface45in the lead base part33. Furthermore, in each of the leads23A and23B, each of the base part main surface37and38extends along the length direction in the lead base part33, from the base part edge surface45to the base part edge surface46.

In the lead base part33of each of the leads23A and23B, as shown inFIG.5, etc., it is preferable that the boundary between each of the base part main surfaces37and38and the base part edge surface41, and also the boundary between each of the base part main surfaces37and38and the base part edge surface42take the shape of an “R” (a arc shape). In this case, in each of the leads23A and23B, the boundary between each of the base part main surfaces37and38and the base part edge surface41takes the shape of an arc, as does the boundary between each of the base part main surfaces37and38and the base part edge surface42, in the cross section of the lead base part33orthogonal to (or approximately orthogonal to) the length direction.

In each of the leads23A and23B, the lead protruding part35protrudes from the base part edge surface46of the lead base part33toward one side of the length direction, and protrudes from the base part edge surface46toward the side opposite the side where the base part edge surface45is located in the length direction. Furthermore, in each of the leads23A and23B, the lead protruding part35is connected to the end portion on the side where the base part edge surface41is located in the base part edge surface46of the lead base part33. In each of the leads23A and23B, the lead protruding part35is formed in the shape of a plate, and the direction of the plate thickness of the lead protruding part35corresponds, or approximately corresponds, to the height direction.

In each of the leads23A and23B, the lead bent part36is bent relative to the lead protruding part35toward one side of the height direction and bent toward the side faced by the base part main surface37of the lead base part33in the height direction. Furthermore, in each of the leads23A and23B, the lead bent part36is connected to the end portion of the lead protruding part35on the side opposite that where the base part edge surface41is located. In each of the leads23A and23B, the lead bent part36is formed in the shape of a plate, and its direction of the plate thickness corresponds, or approximately corresponds, to the width direction. In each of the leads23A and23B, the lead bent part36protrudes toward the side faced by the base part main surface37with respect to the lead base part33and the lead protruding part35. In each of the leads23A and23B, the lead bent part36is arranged either at, or approximately at, the center position in the width direction.

Since the leads23A and23B are formed in the above-described manner, each of the leads23A and23B is either in the shape or approximate shape of a “T” in projection in the length direction. In each of the leads23A and23B, the cross section orthogonal, or approximately orthogonal, to the length direction that passes the lead protruding part35and the lead bent part36is either in the shape or approximate shape of an “L”. The leads23A and23B are formed in the same, or approximately the same, shape.

In the battery1, each of the leads23A and23B is arranged in the inner cavity8in such a manner that the width direction corresponds, or approximately corresponds, to the depth direction of the battery1. Furthermore, in each of the leads23A and23B arranged in the in the inner cavity8, the length direction corresponds, or approximately corresponds, to the lateral direction of the battery1and the height direction corresponds, or approximately corresponds, to the height direction of the battery1.

In each of the leads23A and23B arranged in the inner cavity8, the base part main surface (first base part main surface)37of the lead base part33faces the side where the lid member5is located in the height direction of the battery1. In each of the leads23A and23B, the lead base main surface (second base main surface) of the lead base part33faces the side where the electrode groups2A and2B are located according to the height direction of the battery1. In one example, in each of the leads23A and23B, the base part main surfaces37and38are parallel to, or approximately parallel to, the depth direction and the lateral direction of the battery1, and are parallel to, or approximately parallel to, the inner surface and the outer surface of the lid member5. In this case, in each of the leads23A and23B, the base part main surfaces37and38are orthogonal, or approximately orthogonal to, the height direction of the battery1.

As the leads23A and23B are arranged in the inner cavity8as described above, in the lead base part33of each of the leads23A and23B, the base part edge surface (first base pat edge surface)41constitutes the edge of one side in the depth direction of the battery1, and the base part edge surface (second base part edge surface)42constitutes the edge opposite the base part edge surface41in the depth direction of the battery1. In the lead base part33of each of the leads23A and23B, the base part edge surface45constitutes the edge of one side in the lateral direction of the battery1, and the base part edge surface46constitutes the edge opposite the base part edge surface45in the lateral direction of the battery1.

In each of the electrical connection structures in a pair, the current collecting tab (first current collecting tab)17A is joined with the lead base part (first lead base part)33of the lead23A, and the current collecting tab (second current collecting tab)17B is joined with the lead base part (second lead base part)33of the lead23B. In the present embodiment, in each of the leads23A, a joint part connected to the corresponding one of the current collecting tabs17A is formed in the base part main surface37of the lead base part33. In each of the leads23B, a joint part connected to the corresponding one of the current collecting tabs17B is formed in the base part main surface37of the lead base part33.

In each pair of electrical connection structures, the leads23A and23B are arranged in a shifted layout in the lateral direction of the battery1. In each of the electrical connection structures in a pair, the lead base part33of the lead23A is located on the opposite side of the lead base part33of the lead23B with respect to the electrode terminal21, in the lateral direction of the battery1. Therefore, in each of the electrical connection structures in a pair, the joint portion where the current collecting tab17A is connected to the lead base part33of the lead23A is located on the opposite side of the joint portion where the current collecting tab17B is connected to the lead base part33of the lead23B, with respect to the electrode terminal21.

In each of the electrical connection structures in a pair, the lead protruding part (first lead protruding part)35and the lead bent part (first lead bent part)36of the lead23A are either not shifted, or minimally shifted, in the lateral direction of the battery1, with respect to the lead protruding part (second lead protruding part)35and the lead base part (second lead base part)36of the lead23B. Furthermore, in each of the electrical connection structures in a pair, the lead protruding parts35and the lead bent parts36of the leads23A and23B are either not shifted, or minimally shifted, in the lateral direction of the battery1, from the electrode terminal21. In each of the electrical connection structures in a pair, the lead protruding part35of the lead (first lead)23A protrudes in the lateral direction of the battery1toward the lead23B. Furthermore, in each of the electrical connection structures in a pair, the lead protruding part35of the lead (second lead)23B protrudes in the lateral direction of the battery1toward the lead23A.

In each of the leads23A and23B arranged in the inner cavity8, the lead bent part36is bent in the height direction of the battery1toward the side where the lid member5is located with respect to the lead protruding part35. For this reason, in each of the electrical connection structures in a pair, the lead bent part36in each of the leads23A and23B protrudes toward the side where the lid member5is located with respect to the lead base part33and the lead protruding part35. In each of the electrical connection structures in a pair, each of the leads23A and23B is connected to the electrode terminal21at the lead bent part36. Furthermore, in each of the electrical connection structures in a pair, the joint portion where the current collecting tab17A is connected to the lead base part33of the lead23A is located on the opposite side of the joint portion where the current collecting tab17B is connected to the lead base part33of the lead23B, with respect to the parts where the leads23A and23B are connected to the electrode terminal21.

In each of the electrical connection structures in a pair, the lead bent part (second lead bent part)36of the lead23B is adjacent to the lead bent part (first lead bent part)36of the lead23A from one side of the depth direction of the battery1. Furthermore, in each of the electrical connection structures in a pair, the lead bent parts36of the leads23A and23B are located between the lead protruding part35of the lead23A and the lead protruding part35of the lead23B in the depth direction of the battery1. In each pair of electrical connection structures, the leads23B are arranged at a position when the lead23A is rotated around the center axis of the electrode terminal21either 180 degrees or approximately 180 degrees. Thus, in each of the electrical connection structures in a pair, the leads23A and23B are arranged either symmetrically or approximately symmetrically to each other with respect to the center axis of the electrode terminals21. The center axis of each of the electrode terminals21is along the height direction of the battery1.

As described above, in the present embodiment, in each of the electrical connection structures in a pair, the current collecting tab (first current collecting tab)17A of the electrode group (first electrode group)2A is joined with the lead (first lead)23A, and the current collecting tab (second current collecting tab)17B of the electrode group (second electrode group)2B is joined with the lead (second lead)23B, which is a separate lead from the lead23A. In other words, in each of the electrical connection structures in a pair, the leads23A and23B are connected in conjunction to the electrode terminal21. With such a configuration, an amount of current flowing in each of the leads23A and23B can be reduced compared to the configuration in which the current collecting tabs of multiple electrode groups are together joined with a single lead; thus, it is possible to reduce the thickness of each of the leads23A and23B. As the thickness of each of the leads23A and23B is reduced, a space occupied by the connecting members, such as the leads23A and23B, etc., becomes smaller, and it is thereby possible to increase space occupied by the multiple electrode groups2A and2B in the inner cavity8. Thus, it is possible to realize a higher capacity of the electrode groups2A and2B, without increasing the size of the battery1.

In the process of joining each of the paired current collecting tabs17A to the corresponding one of the paired leads23A by ultrasonic welding, etc., and the process of joining each of the paired current collecting tabs17B to the corresponding one of the paired leads23B by ultrasonic welding, etc., breakages of the current collecting tabs are reduced, joint strength is improved, and the thickness of the lead, which is the base member, is reduced compared to in the process of joining the current collecting tabs of multiple electrode groups to a single lead; thus, the processes according to the present embodiment are superior to the above compared processes and assembly efficiency is improved. Thus, by configuring a pair of the electrical connection structures in the above-described manner, it is thereby possible to improve assembly efficiency in the process of forming the electrical connection structures.

In each of the paired leads23A, the corresponding one of the paired current collecting tabs17A is joined with the base part main surface37of the lead base part33, and the base part main surface37faces the side the lid member5is located. Similarly, in each of the paired leads23B, the corresponding one of the paired current collecting tabs17B is joined with the base part main surface37of the lead base part33, and the base part main surface37faces the side the lid member5is located. With the above-described configuration, even when the dimension of each of the leads23A and23B in the height direction of the battery1is reduced, the joint area where the leads23A or23B are joined with the corresponding one of the current collecting tabs17A and17B is suitably ensured, and the corresponding current collecting tab17A or17B is appropriately joined with the lead23A or23B. As the dimension of each of the leads23A and23B in the height direction of the battery1is reduced, the space occupied by the leads23A and23B in the inner cavity8becomes further smaller, and it is thereby possible to further increase the space occupied by the multiple electrode groups2A and2B in the inner cavity8.

In each pair of electrical connection structures, the current collecting tab17A and17B are arranged in a shifted layout in the lateral direction of the battery1. Furthermore, in each of the electrical connection structures in a pair, the joint portion where the current collecting tab17A is connected to the lead base part33of the lead23A is located on the opposite side of the joint portion where the current collecting tab17B is connected to the lead base part33of the lead23B, with respect to the parts where the leads23A and23B are connected to the electrode terminal21. With such a configuration, the process of joining each of the paired current collecting tabs17A to the corresponding one of the paired leads23A and the process of joining each of the paired current collecting tabs17B to the corresponding one of the paired leads23B can come to be performed more easily.

In each of the leads23A and23B, the lead bent part36is bent in the height direction of the battery1toward the side where the lid member5is located with respect to the lead protruding part35. In each of the electrical connection structures in a pair, each of the leads23A and23B is connected to the electrode terminal21at the lead bent part36, and the lead bent part36of the lead23B is adjacent to the lead bent part36of the lead23A from one side of the depth direction (thickness direction) of the battery1. With such a configuration, even if the leads23A and23B are separate components, the process of connecting the leads23A and23B to the electrode terminal21in conjunction can be more easily performed in each of the electrical connection structures in a pair.

In each of the leads23A and23B, the boundary between each of the base part main surfaces37and38and the base part edge surface41takes the shape of an “R”, and the boundary between each of the base part main surfaces37and38and the base part edge surface42takes the shape of an “R”. Thus, in each of the electrical connection structures in a pair, damage of the current collecting tabs17A due to contact between the current collecting tabs17A and the lead23A can be effectively prevented. Similarly, in each of the electrical connection structures in a pair, damage of the current collecting tabs17B due to contact between the current collecting tabs17B and the lead23B can be effectively prevented. The vibration resistance properties, etc. of the battery1as a product can be thus improved.

(Modifications)

In the first modification shown inFIG.7, in each of the electrical connection structures in a pair, the current collecting tab (first current collecting tab)17A is joined with the lead base part (first lead base part)33of the lead23A, and the current collecting tab (second current collecting tab)17B is joined with the lead base part (second lead base part)33of the lead23B. In the present modification, in each of the leads23A, a joint part connected to the corresponding one of the current collecting tabs17A is formed in the base part main surface (second base part main surface)38of the lead base part33. In each of the leads23B, a joint part connected to the corresponding one of the current collecting tabs17B is formed in the base part main surface (second base part main surface)38of the lead base part33. In this modification, the base part main surface38faces the side where the electrode groups2A and2B are located according to the height direction of the battery1in the lead base part33in each of the leads23A and23B. Herein,FIG.7shows a state viewed from one side of the depth direction of the battery1.

As mentioned above, in the present modification, in each of the leads23A and23B, the corresponding one of the current collecting tabs17A and17B is joined with the base part main surface38facing the side where the electrode groups2A and2B are located. With the above-described configuration, even when the dimension of each of the leads23A and23B in the height direction of the battery1is reduced, the joint area where the leads23A or23B is joined with the corresponding one of the current collecting tabs17A and17B is suitably ensured, and the corresponding current collecting tab17A or17B is appropriately joined with the lead23A or23B. Accordingly, as the dimension of each of the leads23A and23B in the height direction of the battery1is reduced, the space occupied by the leads23A and23B in the inner cavity8becomes smaller; for this reason, similarly to the foregoing embodiment, it is thereby possible to increase the space occupied by the multiple electrode groups2A and2B in the inner cavity8.

In another modification, in at least one of the electrical connection structures, one of the current collecting tabs17A and17B is joined with the base part main surface37of the lead (corresponding one of23A or23B) and the other of the current collecting tabs17A and17B is joined with the base part main surface38of the lead (corresponding one of23A or23B). Even with such a configuration, similarly to the foregoing embodiment, etc., it is possible to reduce the space occupied by the leads23A and23B in the inner cavity8, appropriately ensuring a joint area where the lead23A or23B is joined with the corresponding one of the current collecting tab17A or17B. Thus, even in the present modification, it is possible to increase a space occupied by multiple electrode groups2A and2B in the inner cavity8.

In the second modification shown inFIG.8, accordion structures51and52are formed in each of the leads23A and23B. In each of the leads23A and23B, an accordion structure (first accordion structure)51is formed in the lead protruding part35. In each of the leads23A and23B, the accordion structure51renders the lead protruding part35expandable and contractible in the lateral direction of the battery1(the length direction of the lead). Then, in each of the leads23A and23B, the accordion structure51renders the lead protruding part35vibratable in the height direction of the battery1(the height direction of the lead). Furthermore, in each of the leads23A and23B, an accordion structure (second accordion structure)52is formed in the lead bent part36. In each of the leads23A and23B, the accordion structure52renders the lead bent part36expandable and contractible in the height direction of the battery1(the height direction of the lead). Then, in each of the leads23A and23B, the accordion structure52renders the lead bent part36vibratable in the depth direction of the battery1(the width direction of the lead). Also in the present modification, the lead bent part36is formed integrally with the lead protruding part35. The area where the accordion structure51of the lead protruding part35is formed, however, is not connected to the lead bent part36; rather, there is a gap between the area and the lead bent part36. The lead bent part36is not connected to the base part edge surface46of the lead base part33; rather, there is a gap between the lead bent part36and the base part edge surface46. The operations and advantageous effects similar to those of the foregoing embodiment, etc. are achieved in the present modification.

In the present modification, vibration due to external shock applied to the battery1is absorbed by expansion-and-contraction and vibration of the accordion structures51and52of the leads23A and23B. For this reason, the resistance against vibration improves in each of the leads23A and23B. In each of the leads23A and23B, the direction in which expansion and contraction easily occurs and the direction in which vibration easily occurs differ between the accordion structures51and52; therefore, vibration is appropriately absorbed regardless of the direction of vibration. Thus, resistance against vibration is further improved in each of the leads23A and23B. In a modification, in each of the leads23A and23B, only one of the accordion structures51or52is provided.

In the third modification shown inFIG.9, a through-hole53is formed in each of the electrode terminals21in a pair. Each through-hole53penetrates the corresponding one of the electrode terminals21in the height direction of the battery1. In each of the electrode terminals21, one end of the through-hole53is open toward the outside of the battery1, and the other end is open toward the inner cavity8. In each of the electrical connection structures in a pair, the lead bent part (first lead bent part)36of the lead (first lead)23A and the lead bent part (second lead bent part)36of the lead (second lead)23B are jointly inserted into the through-hole53of the electrode terminal21from the inner cavity8. In each of the electrical connection structures in a pair, the lead bent parts36of the leads23A and23B are connected to the electrode terminal21, being inserted into the through-hole53. Herein,FIG.9shows the battery1viewed from one side of the lateral direction, partially shown in a cross section orthogonal, or approximately orthogonal, to the lateral direction.

In the present modification, in each of the electrical connection structures, the lead bent part36of each of the leads23A and23B is joined with the peripheral surface of the through-hole53by laser welding, etc., thereby connecting the leads23A and23B to the electrode terminals21in conjunction. Forming the through-hole53in each of the electrode terminal21renders it easier to join the lead bent part36of each of the leads23A and23B to the peripheral surface of the through-hole53when each electrical connection structure is formed. Thus, the functionality in the process of forming each electrical connection structure is improved. The operations and advantageous effects similar to those of the foregoing embodiment, etc. are achieved in the present modification.

In one modification, the clip plates25A and25B may not be provided. In this case, in each of the electrical connection structures in a pair, the current collecting tab (first current collecting tab)17A is directly joined with one of the base part main surfaces37or38of the lead (first lead)23A, and the current collecting tab (second current collecting tab)17B is directly joined with one of the base part main surface37or38of the lead (second lead)23B.

The number of electrode groups housed in the inner cavity8is not limited to two, provided that number is greater than one. In one modification, three or more electrode groups are housed in the inner cavity8. Even in this case, in each of the electrical connection structures in a pair, the current collecting tab (first current collecting tab) of the first electrode group, which is one of the three or more electrode groups, is joined with the first lead, and the current collecting tab (second current collecting tab) of the second electrode group, which is another of the three or more electrode groups different from the first electrode group, is joined with the second lead, which is separate from the first lead. The first and second leads are jointly connected to the electrode terminal in each electrical connection structure. With such a configuration, it is possible to reduce the thickness of each lead in each electrical connection structure compared to a configuration in which the current collecting tabs of the first and second electrode groups are joined together to a single lead. It is thereby possible to reduce the space occupied by the connecting members such as the leads in the inner cavity8and to increase the space occupied by the multiple electrode groups, similarly to the foregoing embodiment, etc.

If three or more electrode groups are housed in the inner cavity8, it is preferable that the leads provided in a number equal to the number of electrode groups be provided separate from each other in each of the electrical connection structures in a pair. In this case, in each of the electrical connection structures in a pair, the leads to be joined differ between current collecting tabs. Furthermore, in each electrical connection structure, the leads provided in a number equal to the number of electrode groups are jointly connected to a single electrode terminal.

In the foregoing embodiment, the structure of an electric connection to the positive electrode terminal and the structure of an electric connection to the negative electrode terminal are similar to each other; however, the embodiment is not limited to this example. In a modification, only one of the electrical connection structures in a pair can be formed similarly to one of the foregoing embodiments, etc. In other words, it suffices that at least one of the electrical connection structures in a pair is formed in a manner similar to the foregoing embodiment, etc.

According to at least one of the foregoing embodiments and modifications, a first current collecting tab of a first electrode group, which is one of multiple electrode groups, is joined with a first lead, and a second current collecting tab of a second electrode group, which is another electrode group different from the first electrode group among the multiple electrode groups, is joined with a second lead, which is formed separate from the first lead. Furthermore, the first lead and the second lead are jointly connected to the electrode terminal. It is thereby possible, in a configuration in which current collecting tabs of multiple electrode groups protrude toward a side where a lid member is located, to provide a battery with which the space occupied by multiple electrode groups in an inner cavity of an exterior container can be increased.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.