JP6737591B2 - Laminated battery electrode plate laminated fixing structure - Google Patents

Description

The present invention relates to a technique for electrically connecting electrode plates of a laminate-type battery such as a lithium-ion secondary battery, and more specifically, to firmly connect electrodes in a stacked state. The present invention relates to an electrode plate laminated fixing structure.

The lithium-ion battery includes a sheet-shaped electrode plate having an active material on both front and back surfaces of a current collector made of metal foil. A positive electrode plate and a negative electrode plate are prepared, and a required number of these electrode plates are alternately laminated. The layers are laminated with the active material-free ends of the positive electrode plate and the negative electrode plate facing in opposite directions. The overlapping ends of the electrode plates are connected to each other, and the tabs are also connected in an overlapping manner.

The connection between the electrode plates and the tab is performed by ultrasonic welding as disclosed in Patent Document 1 below, for example.

However, in ultrasonic welding, ultrasonic waves are generated in a state where metals to be joined are superposed on each other to cause atomic bonding at the bonding interface.However, impurities such as oxide film and dirt are on the surface of the metals to be bonded. As such, they may remain at the bond interface. For this reason, the portion joined by ultrasonic welding may come off by vibration even if it is intended to be joined so as to obtain good stability.

JP, 2005-222788, A

Therefore, the main object of the present invention is to firmly connect the electrode plates to each other.

Means therefor is an electrode plate laminated fixing structure for connecting the connection parts of a connection part group formed by overlapping the connection parts of a plurality of stacked electrode plates in a laminated battery, wherein the connection part group is , An ultrasonic welding portion for joining the electrode plates to each other is formed, at a position adjacent to the formed ultrasonic welding portion in the connection portion group, a fixture for sandwiching the connection portion group in the thickness direction is provided. The fixing member is fixed, and the fixing member is formed of a material having conductivity , and is pressed against the outer surface of the connecting portion group directly or indirectly , and is pierced into the connecting portion group integrally with the pressing contact portion and is opposite. An annular main body member having a notch portion which is crimped after forming a circular shape in plan view penetrating into the side surface, and the tip end portion of the notch portion spreads in the surface direction of the connecting portion group and the connecting portion group and the press contact portion. an electrode plate laminated and fixed structure has been laminated battery structure in fastening member which have a clamping portion for pressing directly or indirectly to the connection portion group is sandwiched between in cooperation with.

In this configuration, the pressure contact portion, the notch portion, and the holding portion of the fixture compress the connecting portion group from different directions to hold the laminated state of the connecting portion, and directly or indirectly adhere to the connecting portion group. , Electrically connecting the connection parts of the electrode plates.

According to the present invention, the connecting portion laminated by the fixture having the notch portion that cuts through the connecting portion group and penetrates, the pressure contact portion that is integral with the notch portion, and the holding portion that clamps the connecting portion group in cooperation with the pressure contact portion. Since the electrodes are fixed, the connection between the electrode plates can be firmly performed so as not to come off due to vibration.

FIG. 3 is a perspective view showing an electrode plate laminated fixing structure. FIG. 3 is a plan view of the electrode plate laminated fixing structure. The schematic block diagram of a lithium ion secondary battery. Sectional drawing which shows the structure of the electrode plate part in a lithium ion secondary battery. Sectional drawing of the fixing tool part in an electrode plate laminated fixing structure. The one side sectional side view showing the state before fixing a fixture. Sectional drawing of the fixture part in the electrode plate laminated fixing structure which concerns on another example. The top view of the electrode plate lamination fixing structure which concerns on another example. Sectional drawing of the fixture part in the electrode plate laminated fixing structure which concerns on another example.

An embodiment for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing an outline of an electrode plate laminated fixing structure 11 of a laminated battery, and FIG. 2 is a plan view of the electrode plate laminated fixing structure 11. As shown in these figures, the electrode plate laminated fixing structure 11 is configured by using a fixing tool 12.

First, a schematic structure of a lithium ion secondary battery 51 as an example of a laminated battery will be described with reference to FIG. In the lithium-ion secondary battery 51, a sheet-shaped positive electrode plate 52 and a negative electrode plate 53 in which active materials are provided on both front and back surfaces of a current collector made of a metal foil, as shown in FIG. A required number of sheets are laminated with a separator 54 interposed therebetween. The electrode plates 52, 53 have connection parts 52a, 53a having no active material at one end, and the connection parts 52a, 53a are laminated in the positive electrode plate 52 and the negative electrode plate 53 in opposite directions. It The connection portion 52a of the positive electrode plate 52 and the connection portion 53a of the negative electrode plate 53 are overlapped with each other, and the rectangular tab 55 is partially overlapped and connected to the connection portions 52a and 53a in this state. There is.

Such electrode plates 52 and 53 are covered with an insulating sheet 56 as shown in FIG. 1, and are covered with a laminate film 57 together with an electrolytic solution (not shown) with the tab 55 exposed at its tip. (See Figure 3).

The thickness of the tab 55 is set appropriately and is thicker than the metal foil forming the electrode plates 52 and 53. This thickness is, for example, about 0.1 mm to 0.5 mm.

In the illustrated example, the positive electrode tab 55a is provided on one of the two opposite sides of the lithium ion secondary battery 51 and the negative electrode tab 55b is provided on the other side. 51 may have a tab 55a for the positive electrode and a tab 55b for the negative electrode arranged side by side on the same side.

Next, the laminated fixing structure 11 for connecting the connecting portions 52a, 53a of the electrode plates 52, 53 to each other will be described.

The connecting portion group 13 formed by the connecting portions 52a, 53a of the plurality of electrode plates 52, 53 overlapping each other has a thin sheet shape as shown in FIG. A part of the tab 55 is overlapped with an intermediate part of the connecting part group 13, and an appropriate number of fixing tools 12 are fixed to the overlapped part. The number and arrangement of the fixtures 12 are set appropriately. FIG. 5 is a cross-sectional view of the fixture 12 in the state where it is fixed by the fixture 12 and its vicinity.

As shown in FIG. 5, this electrode plate laminated fixing structure 11 has a pressure contact portion 14 that directly or indirectly pressure contacts the outer surface of the connection portion group 13 and a portion of the pressure contact portion 14 that is integrally formed with the pressure contact portion 14 and pierces the connection portion group 13 on the opposite side. The notch portion 15 penetrating the surface and the tip of the notch portion 15 spreads in the surface direction of the connecting portion group 13 to sandwich the connecting portion group 13 in cooperation with the press contact portion 14 to directly or indirectly press contact with the connecting portion group 13. The fixture 12 having the holding portion 16 is provided.

The fixture 12 is made of an electrically conductive material that can be cold forged, and is composed of a main body member 21 and a fastening member 22 as shown in FIG. The main body member 21 is a member that forms the above-described press contact portion 14 and the cut portion 15, and the fastening member 22 is a member that forms the above-mentioned holding portion 16.

The main body member 21 has a cylindrical portion 23 having a cylindrical shape, and a brim-shaped annular portion 24 extending outward from one end of the cylindrical portion 23. The cylindrical portion 23 is formed to be longer than the thickness of the connecting portion group 13, and the base side portion is a cut portion, and the distal end side portion 23a on the distal end side of the cylindrical portion 23 is pierced into the connecting portion group 13 It is the part that can be crimped. The tip end of the cylindrical portion 23 is formed in a sharp shape that easily pierces the connection portion group 13.

The annular portion 24 is smoothly continuous from the cylindrical portion 23, and the portion on the cylindrical portion 23 side is provided with a recess 25 that bulges in a direction away from the connecting portion group 13. The length of the annular portion 24 in the outer peripheral direction is set to a length such that when the annular portion 24 is fixed to the connecting portion group 13, sufficient clamping can be performed in relation to the thickness of the connecting portion group 13 and the fastening member 22.

The fastening member 22 is in the shape of a circular dish having a through hole 26 in the center. The size of the through hole 26 is formed so that the cylindrical portion 23 of the main body member 21 can be loosely fitted therein. The edge portion 27 of the through hole 26 has some flat portions and is formed at a portion facing the recess 25 of the main body member 21. Further, the edge portion 27 is the most protruding portion of the fastening member 22 in the direction approaching the connecting portion group 13, and serves as a pressing portion that exerts a strong pressing force on the connecting portion group 13.

A circle that extends obliquely outward from the edge portion 27 in a direction away from the connection portion group 13 and swells in a direction away from the connection portion group 13 at a portion facing the outer peripheral edge 24a of the annular portion 24 of the main body member 21. An arc-shaped recess 28 is formed, and the outer peripheral edge 29 of this recess 28 slightly protrudes toward the connecting portion group 13 side.

The main body member 21 and the fastening member 22 of the fixture 12 having such a configuration are opposed to each other with the connecting portion group 13 and the tab 55 sandwiched therebetween, and the main body member 21 and the fastening member 22 sandwich and press the fixed portion of the connecting portion group 13. Then, the cylindrical portion 23 of the main body member 21 pierces the connecting portion group 13 and is pulled out to the opposite side, and the portion cut by the cylindrical portion 23 falls off from the inside of the cylindrical portion 23. The distal end side portion 23a of the cylindrical portion 23 is crimped as shown in FIG. 5, and the distal end side portion 23a of the cylindrical portion 23 bent and deformed so as to be folded back presses the fastening member 22.

As a result, the electrode plate laminated fixing structure 11 as described above is obtained. Specifically, the electrode plate laminated fixing structure 11 includes a pressure contact portion 14 that indirectly pressure-contacts the outer surface of the connection portion group 13 via a tab 55, and the pressure contact portion 14 integrally penetrates the tab 55 and the connection portion group 13. And a notch portion 15 penetrating to the opposite surface of the connecting portion group 13 and a tip end portion of the notch portion 15 that spreads in the surface direction of the connecting portion group 13 and clamps the connecting portion group 13 in cooperation with the press contact portion 14. The fixture 12 is provided with a sandwiching portion 16 that is in direct pressure contact with the connecting portion group 13.

At the portion of the connecting portion group 13 provided with the fixture 12, the main body member 21 and the fastening member 22 forming the press contact portion 14, the notch portion 15 and the sandwiching portion 16, specifically, the concave portion 25 of the main body member 21 and the fastening member. The connecting portion group 13 is compressed in the thickness direction by the edge portion 27 of 22 and the outer peripheral edge 24a of the main body member 21 and the outer peripheral edge 29 of the fastening member 22 so as to be waved, and the notch portion 15 and the sandwiching portion 16 are formed. A sandwiched portion 17 sandwiched between is formed.

In the electrode plate laminated fixing structure 11 thus configured, the main body member 21 and the fastening member 22 are integrally pressed against the connecting portion group 13 and the tab 55 in the vicinity of the portion where the notch 15 is pierced. The connecting portion group 13 and the tab 55 are compressed in the thickness direction, the sandwiched portion 17 is formed, and the main body member 21 and the fastening member 22 are fixed by caulking, so that a high degree of adhesion and vibration etc. A strong fixed state that does not easily separate will be obtained.

Moreover, since the holding portion 16 is formed on the fastening member 22 which is a member different from the main body member 21 to be crimped, the contact can be softened as compared with the case where the crimped portion is directly pressed. Moreover, since the edge portion 27 of the retaining member 22 that serves as the sandwiching portion 16 is formed of a horizontal surface, the connecting portions 52a and 53a are accidentally broken even if they are pressed against the connecting portions 52a and 53a of the electrode plates 52 and 53. It is possible to avoid such a thing.

Further, since the distal end side portion 23a of the cylindrical portion 23 of the main body member 21 is caulked, the height of the main body member 21 when fixed is reduced. In addition, the fastening member is formed in a dish shape, and the distal end side portion 23a of the tubular portion 23 is accommodated therein, so that the fixing tool 12 as a whole can be formed thin. Therefore, it is suitable as a fixing structure for the electrode plate covered with the laminate 56.

Since the tabs 55 are overlapped and fixed to the connecting portion group 13, the tabs 55 can be easily connected. The tab 55 can be inserted inside instead of overlapping the outer surface of the connecting portion group 13.

Furthermore, since the tab 55 and a part of the connecting portion group 13 are cut off when the cylindrical portion 23 of the main body member 21 is fixed, the weight can be reduced.

Hereinafter, other examples will be described. In this description, parts that are the same as or similar to those described above are given the same reference numerals, and detailed description thereof is omitted.
FIG. 7 is a cross-sectional view of the fixture 12 in the state where the fixture 12 is fixed in the electrode plate laminated fixing structure 11 according to another example and the vicinity thereof. As shown in this figure, a plurality of cutout portions 15 of the fixture 12 are provided, and these cutout portions 15 are intermittently arranged along the contour of the press contact portion 14. Specifically, the main body member 21 has a circular ring-shaped portion 24, and five standing pieces 31 of the same shape and size are evenly arranged on the ring-shaped portion 24. The shape of the standing piece 31 is set appropriately, but in this example, it is formed in a substantially semi-elliptical shape. The fastening member 22 is formed in a substantially disc shape, and has a convex portion 32 projecting toward the connecting portion group 13 side over the entire circumference at a portion slightly inside the portion corresponding to the standing piece 31 on the inner circumferential side. .. A portion on the outer peripheral side of the convex portion 32 has a deforming curved portion 33 that allows the standing piece 31 to enter and deforms the tip side portion of the standing piece 31. The deformable bending portion 33 is for flattening as much as possible in order to expand the tip end side portion 31a of the standing piece 31 in the outer peripheral direction and then deform it so as to be folded back toward the connecting portion group 13 side. The tip edge 33a of the deformable curved portion 33 has a gentle slope that is nearly horizontal, and is formed at a position facing the recess 25 of the main body member 21.

Specifically, the electrode plate laminated fixing structure 11 including such a fixing member 12 includes a pressure contact portion 14 that is indirectly pressure contacted to the outer surface of the connection portion group 13 via the tab 55, and a tab contact integrally with the pressure contact portion 14. 55 and the notch portion 15 that pierces the connecting portion group 13 and penetrates to the surface on the opposite side of the connecting portion group 13, and the tip end portion of the notch portion 15 spreads in the surface direction of the connecting portion group 13 to press the connecting portion group 13 into contact with each other. It is provided with a fixture 12 having a sandwiching portion 16 that is sandwiched in cooperation with the contact portion group 13 and is directly pressed against the connecting portion group 13. In the portion of the connecting portion group 13 provided with the fixture 12, the concave portion 25 of the main body member 21, the tip edge 33a of the deformed curved portion 33 of the fastening member 22, the outer peripheral edge 24a of the main body member 21, and the convex portion of the fastening member 22. By 32, the connecting portion group 13 is compressed in the thickness direction and is deformed so as to be wavy, and the sandwiched portion 17 sandwiched between the notch portion 15 and the sandwiching portion 16 is formed.

Even with the electrode plate laminated fixing structure 11 configured as described above, a high degree of adhesion and a strong fixed state that is not easily separated by vibration or the like can be obtained, as described above.

FIG. 8 is a plan view of an electrode plate laminated fixing structure 11 according to another example. In this electrode plate laminated fixing structure 11, the connecting portion group 13 has an ultrasonic welding portion 35 that joins the electrode plates 52 and 53 together. Specifically, an ultrasonic welding portion 35 that joins the connecting portion group 13 and the tab 55 to each other is formed in the overlapping portion. A plurality of ultrasonic welds 35 are formed with a predetermined interval. The fixture 12 is fixed in non-contact with the ultrasonic welding portion 35 or in contact with the ultrasonic welding portion 35.

In the electrode plate laminated fixing structure 11 having such a configuration, since the ultrasonic welding portion 35 serves as a conducting portion and the fixing tool 12 obtains the joined state between the connecting portion group 13 and the tab 55, reliable conduction can be obtained. Moreover, since the ultrasonic welding portion 35 is formed before the fixing of the fixing tool 12, the positional relationship between the connecting portion group 13 and the tab 55 is stable, and the fixing operation of the fixing tool 12 can be performed easily and accurately. Therefore, a desired fixed state without displacement can be obtained.

The ultrasonic welding portion 35 can be formed in a portion other than the portion where the tab 55 is overlapped.

FIG. 9: is sectional drawing of the fixing tool 12 part of the electrode plate laminated fixing structure 11 which concerns on another example.

The electrode plate laminated fixing structure 11 includes a connecting portion 37 for connecting the electric wire 61 to the retaining member 22 of the fixture 12. The connecting portion 37 is integrally formed in a strip shape on the outer peripheral edge of the fastening member 22, and the connecting portion 37 is formed with an annular crimping portion 37 a for crimping the conductor 62 of the electric wire 61.

The above is a configuration of one embodiment for carrying out the present invention, and the present invention is not limited to the above configuration, and other configurations can be adopted.

11... Electrode plate laminated fixing structure 12... Fixing device 13... Connection part group 14... Pressure contact part 15... Notch part 16... Clamping part 17... Clamped part 21... Main body member 22... Fastening member 51... Lithium ion secondary battery 52, 53... Electrode plates 52a, 53a... Connection part 55... Tab

Claims (5)

An electrode plate laminated fixing structure for connecting the connecting parts of a connecting part group formed by overlapping the connecting parts of a plurality of stacked electrode plates in a laminated battery,
In the connection portion group, an ultrasonic welding portion for joining the electrode plates to each other is formed,
At a position adjacent to the formed ultrasonic welding portion in the connection portion group, a fixture for sandwiching in the thickness direction through the connection portion group is fixed.
The fixture is formed of a conductive material,
An annular shape having a pressure contact portion that directly or indirectly press-contacts the outer surface of the connection portion group , and a notch portion that is integrally formed with the pressure contact portion and that is formed into a circular shape in plan view that pierces the connection portion group and penetrates to the opposite surface. Body member of
Closure to have a clamping portion for pressing the connection portion group spreads in the plane direction of the connection portion group directly or indirectly to the connection portion group is sandwiched between in cooperation with the pressure-contacting portion at the distal end of the cut portion An electrode plate laminated fixing structure for a laminated battery, which is composed of members . A tab partially overlapped with the connecting portion group,
The electrode plate laminated fixing structure for a laminate type battery according to claim 1 , wherein the ultrasonic welding portion and the fixture are provided in a portion of the connection portion group where the tabs are overlapped. A plurality of the ultrasonic welds are intermittently formed,
The electrode plate laminated fixing structure for a laminate type battery according to claim 1 or 2, wherein a plurality of the fixtures are formed at positions sandwiching the ultrasonic weld . The electrode of the laminated battery according to any one of claims 1 to 3 , wherein a plurality of the cutouts of the fixture are provided, and the cutouts are intermittently arranged along the contour of the press contact portion. Board laminated fixed structure. The inner peripheral end of the sandwiching portion projects in the inner peripheral direction and faces the cut portion,
The laminate according to any one of claims 1 to 4, wherein a sandwiched portion, which is an end portion of the connecting portion group sandwiched by the pressure contact portion and the sandwiching portion, is sandwiched by a notch portion. Type battery electrode plate laminated fixing structure.

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