Patent Application
20240079742
This application is based upon and claims the benefit of priority to Japanese Patent Application No. 2022-140737 filed on Sep. 5, 2022, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a battery and a method for producing the battery.
Conventionally, there are known batteries in each of which a current-collecting member connected to a power-generating element housed in an outer casing and an external terminal placed outside the outer casing are connected by a rivet-shaped member. For example, Japanese unexamined patent application publication No. 2016-054109 (JP2016-054109A) discloses a battery in which a protruding portion of an internal terminal is inserted into a through hole of an external terminal and swaged. This publication JP2016-054109A discloses the internal terminal whose protruding portion has a hollow cylindrical distal end portion with a cutout formed to midpoint in the cylindrical portion.
The conventional arts described above have the following problems. To reliably connect constituent members by joining them, it is necessary to precisely identify the boundary position between the members to be joined. For example, it is conceivable to take an image of target parts of the members to be joined and its surroundings, and identify a joining target site. However, the boundary of the members may not always clearly appear in the captured image depending on the shape of each member before joining. If the joined site deviates from the boundary of the members, a battery may be produced in which the constituent members are unstably connected.
The present disclosure has been made to address the above problems and has a purpose to provide a battery in which constituent members are appropriately joined at their boundaries, and provide a method for producing the battery.
To achieve the above-mentioned purpose, one aspect of the present disclosure provides a battery comprising: an outer casing; a power generating element housed in the outer casing; a first current collecting member connected to the power generating element; and a second current collecting member placed outside the outer casing, wherein either one of the first current collecting member and the second current collecting member includes a plate-shaped portion that has a first surface and a second surface opposite the first surface, and the plate-shaped portion is placed along the outer casing with the second surface facing the outer casing, and the other one of the first current collecting member and the second current collecting member includes: a through part extending through the outer casing; and a contact part provided continuous to the through part and in contact with the first surface of the plate-shaped portion, the contact part includes a peripheral end portion that is located apart from the through part and includes a portion joined to the first surface of the plate-shaped portion, the peripheral end portion further includes a non-joined portion not joined to the first surface of the plate-shaped portion, the non-joined portion including an edge portion located on a side facing the first surface and provided with a tapered surface generating a gap with respect to the first surface so that the gap is smaller at a position closer to the through part, the tapered surface has a maximum size that is: 0.1 mm or more in a direction from the peripheral end portion toward the through part; and 0.03 mm or more in a thickness direction of the peripheral end portion.
In the battery configured as above, the first surface of either the first current collecting member or the second current collecting member is joined in contact with the contact part of the other one, the first current collecting member or the second current collecting member, and they are reliably electrically connected to each other. In contrast, for the non-joined portion of the peripheral end portion, the edge portion of the peripheral end portion of the contact part is provided with the tapered surface, so that a gap is formed between the peripheral end portion and the first surface. When the peripheral end portion and the first surface are photographed to capture an image of their boundary and its surroundings, the position of the boundary can be easily ascertained from this captured image. If the joined portion is also formed with the tapered surface before joining, the position of the boundary between the peripheral end portion and the first surface can be easily determined and thus they are likely to be joined at an appropriate position. Therefore, the battery is completed with the first current collecting member and the second current collecting member appropriately joined to each other.
Another aspect of the present disclosure provides a method for producing a battery, the battery comprising: an outer casing; a power generating element housed in the outer casing; a first current collecting member connected to the power generating element; and a second current collecting member placed outside the outer casing, wherein either one of the first current collecting member and the second current collecting member to be used in the method includes a plate-shaped portion that has a first surface and a second surface opposite the first surface, and the other one of the first current collecting member and the second current collecting member to be used in the method includes: a through part extending through the outer casing; and a to-be-swaged part that is continuous to the through part and is to be swaged, the to-be-swaged part including a distal end portion provided with a tapered surface at an edge portion on one surface, the tapered surface being tapered with a depression amount that is smaller at a position closer to the through part, and the tapered surface has a maximum size that is: 0.1 mm or more in a direction from the distal end portion of the to-be-swaged part toward the through part; and 0.03 mm or more in a thickness direction of the to-be-swaged part, and wherein the method comprises: placing the one of the first current collecting member or the second current collecting member, having the plate-shaped portion, so that the plate-shaped portion extends along the outer casing with the second surface facing the outer casing; placing the other one of the first current collecting member or the second current collecting member, having the through part, so that the through part extends through the outer casing and the to-be-swaged part protrudes beyond a level of the first surface of the plate-shaped portion; swaging the to-be-swaged part so that the one surface of the to-be-swaged part provided with the tapered surface faces the first surface of the plate-shaped portion to form a contact part which contacts the first surface; irradiating light onto the contact part and a part of the first surface not covered by the contact part to capture an image including an end portion of the contact part; and joining the contact part and the first surface at a position of the end portion of the contact part, the position being ascertained from the image.
In the battery producing method configured as above, either the first current collecting member or the second current collecting member includes the plate-shaped portion, and the other one includes the to-be-swaged part which is a target portion of swaging. This to-be-swaged part is provided, at its distal end portion, with the tapered surface in advance. This tapered surface is caused to face the first surface of the plate-shaped portion by the swaging, so that a gap is likely to be formed between the plate-shaped portion and the contact part after swaging. In this condition, an image of the contact part and the part of the first surface not covered by the contact part is captured by light irradiation. The gap forms a shadow in the captured image, allowing the position of the peripheral end portion of the contact part can be easily determined. Thus, the contact part and the first surface can be appropriately joined to each other.
A detailed description of an embodiment of the present disclosure will now be given referring to the accompanying drawings. In the present embodiment, this disclosure is embodied as a battery 1 shown in
The outer casing 2 consists of a casing body 4 and a lid 5. The power generating element 3 is housed in the casing body 4. The lid 5 is provided with external terminals 6 and 7, and a sealing cap 8. These external terminals 6 and 7 are individually connected to either the positive electrode sheet or the negative electrode sheet of the power generating element 3 within the outer casing 2. The sealing cap 8 closes a liquid inlet provided in the lid 5. An outer plate 21 is a flat-plate-shaped member integrally connected to the external terminal 6. This outer plate 21 is attached to the lid 5 with a rivet 20. The external terminal 6 is electrically connected to the rivet 20 through the outer plate 21, as described in detail below.
The battery 1 is internally provided with a current collecting member 9 and a current collecting member 11, as shown in
The essential feature of the battery 1 in the present embodiment is the connecting configuration between the current collecting member 9 and external terminal 6, more specifically, the joining configuration between the current collecting member 9 and the rivet 20.
The lid 5 is formed with a hole 19 for attachment of the rivet 20. Furthermore, the current collecting member 9, the insulation members 17 and 18, and the outer plate 21 are formed with holes at a position aligned with the hole 19. In
The current collecting member 9 includes a plate-shaped portion 91 placed along the lid 5. This plate-shaped portion 91 is illustrated in
The through part 13 of the rivet 20 is placed in the hole 19 of the lid 5 and extends through the lid 5. The flange part 14 is placed at one end of the through part 13 and located on the outside of the lid 5, and has a larger diameter than the through part 13. The contact part 15 is provided continuous to and at the other end of the through part 13, and located on the inside of the lid 5, and has a larger diameter than the through part 13. The flange part 14 and the contact part 15 are larger than the hole 19 in diameter.
As shown in
However, between the contact part 15 and the flange part 14, there are sandwiched the insulation members 17 and 18 in addition to the outer plate 21, lid 5, and current collecting member 9. The insulation member 17 serves to insulate the current collecting member 9 from the lid 5, while the insulation member 18 serves to insulate the outer plate 21 from the lid 5. Accordingly, the lid 5 is insulated from the outer plate 21 and the current collecting member 9.
Next, a contact site between the contact part 15 of the rivet 20 and the plate-shaped portion 91 of the current collecting member 9 will be described below. The contact part 15 is an annular portion whose diameter is widened by swaging as described later, and includes a peripheral end portion 16 along its outer peripheral end. Specifically, this peripheral end portion 16 is an annular portion circumferentially extending along a radial end far from the through part 13. The peripheral end portion 16 includes a joined portion 61 joined to the first surface 911 of the plate-shaped portion 91. In
The non-joined portion 62 of the peripheral end portion 16 includes a portion formed with a tapered surface as shown in
The tapered surface of the edge portion 161 in the present embodiment has a maximum size of 0.1 mm or more from the peripheral end portion 16 (i.e., the outer end 16A) in a direction toward the through part 13 and a maximum size of 0.03 mm or more in a thickness direction of the peripheral end portion 16, as shown in
As described later, the end portion of a rivet before swaging is provided with a tapered surface in advance. However, the peripheral end portion 16 of the rivet 20 may be deformed from its original shape due to swaging. In the rivet 20 of the battery 1, even the non-joined portion 62 does not always maintain the exact shape of the tapered surface of the rivet before swaging. That is, the maximum size of the tapered surface represents the size of a part of the entire peripheral end portion 16, where the tapered surface is maximum.
Furthermore, the maximum size of the tapered surface of the edge portion 161 in the present embodiment is 0.4 mm or less from the peripheral end portion 16 (i.e., the outer end 16A) in the direction toward the through part 13 and 0.1 mm or less in the thickness direction of the peripheral end portion 16, preferably. If the tapered surface of the edge portion 161 is too large, the contact area between the contact part 15 and the plate-shaped portion 91 tends to be small, which may affect the electrical conduction between them.
Next, a method for producing the battery 1 will be described below referring to a flowchart of
The rivet 22 before swaging includes a to-be-swaged part 24 which is a target portion to be swaged, a through part 25, and the flange part 14 as shown in
In step 1, the to-be-swaged part 24 and the through part 25 are inserted in the holes of the current collecting member 9 and others members or parts. The through part 25 extends through the hole 19 of the lid 5. This through part 25 corresponds to the through part 13 of the rivet 20 after swaging. A part of the to-be-swaged part 24 protrudes upward beyond the level (i.e., the height) of the first surface 911 of the plate-shaped portion 91. This protruding portion (i.e., the to-be-swaged part 24) will be formed into the contact part 15 of the rivet 20 by swaging. The flange part 14 of the rivet 22 corresponds to the flange part 14 of the rivet 20 after swaging.
In
In the rivet 22 before swaging, the distal end portion 26 of the to-be-swaged part 24, located at the opposite end from the flange part 14, is formed with a tapered surface 31 on the inner surface 241 and a tapered surface 32 on the outer surface 242 as shown in
The tapered surface 31 of the inner surface 241 is formed as a truncated conical surface over the entire circumference of the to-be-swaged part 24 in order to allow the to-be-swaged part 24 to be appropriately plastically deformed by swaging. The inner surface 241 of the rivet 22 in the present embodiment is formed with a tapered surface 31 at a taper angle of 15° to 40°. The tapered surface 31 may be formed to the leading end 26A of the distal end portion 26 or the distal end portion 26 may include an area formed with no tapered surface 31A, as shown in
In contrast, the tapered surface 32 of the outer surface 242 is tapered with a depressed amount that is smaller at a position closer to the through part 25, as shown in
The tapered surface 32 of the rivet 22 in the present embodiment is 0.4 mm or less from the leading end 26A of the to-be-swaged part 24 in the direction toward the through part 25 and 0.1 mm or less in the thickness direction of the to-be-swaged part 24, as shown in
Returning to the process in
By the swaging in step 2, the to-be-swaged part 24 of the rivet 22 including the distal end portion 26 is pushed radially outward, pressing the outer surface 242 against the first surface 911 of the plate-shaped portion 91. The to-be-swaged part 24, plastically deformed by swaging, becomes the contact part 15 as shown on the right side in
Subsequently, the operator irradiates light onto the contact part 15 of the rivet 20 to capture an image of the area including the peripheral end portion 16 which is a radial outer end portion of the contact part 15 and a part of the first surface 911, around the peripheral end portion 16 and uncovered with the contact part 15 (Step 3). Since the punch 28 does not contact the outer surface 242 of the rivet 22 during swaging, the tapered surface 32 of the outer surface 242 of the rivet 22 before swaging is partly maintained even after swaging and forms the edge portion 161 as shown in
By the image processing based on the image 70 captured in step 3, the operator detects the position of the outer end 16A of the peripheral end portion 16 (Step 4). For instance, using the edge detection technique based on brightness/darkness of an image, the position of the boundary edge between the peripheral end portion 16 and the shadow image 71 surrounding thereof is obtained as shown in
Furthermore, the operator performs welding at the outer end 16A of the peripheral end portion 16 detected in step 4 to join the contact part 15 to the first surface 911 of the plate-shaped portion 91 (Step 5). To be specific, as shown in
Thereafter, the operator performs subsequent processes. Specifically, the operator assembles the current collecting member 11 in the same manner as above. Further, the operator inserts the power generating element 3 into the casing body 4 of the outer casing 2, joins the casing body 4 and the lid 5, and injects an electrolyte into the casing body 4. Thus, the battery 1 is completed.
The battery 1 in the present embodiment described in detail above includes the current collecting member 9 connected to the power generating element 3 and the rivet 20 connected to the external terminal 6. The first surface 911 of the plate-shaped portion 91 of the current collecting member 9 and the contact part 15 of the rivet 20 are joined to each other through the joined portion 61. In contrast, in the non-joined portion 62 of the contact part 15, the edge portion 161 of the peripheral end portion 16 has a tapered surface, creating a gap G between the peripheral end portion 16 and the first surface 911 of the current collecting member 9. When the boundary between the peripheral end portion 16 and the first surface 911 including its surroundings are photographed, it is possible to easily ascertain the position of the boundary between the peripheral end portion 16 and the first surface 911 based on the shadow image 71 generated by the gap G. Since the joined portion 61 before joining is provided with the same tapered surface as the non-joined portion 62, it is easy to identify the target position for joining, so that the battery 1 is completed with the peripheral end portion 16 and the first surface 911 appropriately joined at the position of their boundary.
The foregoing embodiments are mere examples and give no limitation to the present disclosure. The present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. For example, in the foregoing embodiment, the technique of the present disclosure is applied to the external terminal 6 (the negative electrode terminal) as a target portion of the battery 1, but may be applied to the external terminal 7 (the positive electrode terminal) or both external terminals. In many cases, as the general materials of rivets, copper is used for a negative electrode terminal and aluminum is used for a positive electrode terminal. In this case, it is higher meaningful to apply the present disclosure to the negative electrode terminal made of copper more rigid than aluminum than to the positive electrode terminal. Further, the present disclosure can be applied to every type of battery.
The shape of the rivet 22, except for the distal end portion 26 of the to-be-swaged part 24, is not limited to the above-mentioned examples. For example, the depth of the hole of the to-be-swaged part 24 may selected with some degree of freedom. Further, the hole of the to-be-swaged part 24 may have a V-shaped cross-section with the inner diameter smaller at a position closer to the through part 25. The shape of the flange part 14 is also selected arbitrarily.
The rivet 22 and the external terminal 6 may be an integral piece. The rivet 22 may be configured such that the flange part 14 is positioned inside the outer casing 2 of the battery 1 and the to-be-swaged part 24 is swaged outside the outer casing 2. In other words, the first current collecting member and the second current collecting member may be located at reversed positions from the foregoing embodiment. The shape of the projecting portion 30 illustrated in
The battery according to the present disclosure may be configured such that the maximum size of the tapered surface is: 0.4 mm or less in the direction from the peripheral end portion toward the through part; and 0.1 mm or less in the thickness direction of the peripheral end portion. If the maximum size of the tapered surface is too large, the joining area may become small or the joining may become unstable. With the tapered surface having an appropriate maximum size or less, the battery can be completed with reliably joined parts.
The battery according to the present disclosure may be configured such that the first current collecting member and the second current collecting member are made of the same kind of conductive material. Those first and second current collecting members made of the same kind of conductive material can be appropriately joined to each other by welding.
The battery according to the present disclosure may be configured such that at least a part of the through part is a columnar portion, the to-be-swaged part is a cylindrical portion continuous to the columnar portion, the tapered surface is formed at the edge portion of an outer surface corresponding to the one surface of the distal end portion of the cylindrical portion, and the swaging is performed to radially press out a part of the cylindrical portion including the distal end portion so that the outer surface of the cylindrical portion contacts the first surface of the plate-shaped portion. This method enables to make the to-be-swaged part including the tapered surface contact with the first surface of the plate-shaped portion.
The present disclosure according to the above configurations can achieve a battery in which constituent members or parts are joined appropriately at their boundaries, and a method for producing the battery.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-140737 | Sep 2022 | JP | national |
