JP5589220B2 - Square battery and method for manufacturing the same - Google Patents

Description

  The present invention relates to a prismatic battery having a flat wound electrode group and a method for manufacturing the same.

  As a background art in this technical field, there is JP 2011-100591 A (Patent Document 1). In the above publication, a configuration of a rectangular lithium ion secondary battery using a flat wound electrode group is described.

  The flat wound electrode group is manufactured by winding a positive electrode sheet and a negative electrode sheet while sandwiching a belt-like separator so as not to contact each other. The positive electrode sheet and the negative electrode sheet are formed by applying a mixed slurry of an active material, a conductive material and a binder to a strip-shaped metal foil to form a mixture layer, and further forming a mixture layer along the long side of the metal foil. A foil exposed portion where a part of the metal foil is exposed is provided.

  The flat wound electrode group is formed so that the positive electrode metal foil exposed portion of the positive electrode sheet and the negative electrode metal foil exposed portion of the negative electrode sheet are opposite to each other so that they are separated from one side and the other side in the winding axis direction. They are rolled up so as to protrude outward in the rotational axis direction. At one end of the flat wound electrode group in the winding axis direction, a positive electrode metal foil laminate is formed by winding and laminating the exposed positive metal foil, and at the other end in the winding axis direction, A negative electrode metal foil laminate is formed by winding and laminating negative electrode metal foil exposed portions. Then, the positive electrode metal foil laminated portion and the negative electrode metal foil laminated portion are connected as a positive electrode connecting portion and a negative electrode connecting portion to an electrical connection member to the outside of the battery by a technique such as ultrasonic bonding.

  According to the flat wound electrode group having the above-described configuration, the electrical connection member and the electrical connection member at a plurality of positions on each metal foil laminated portion over the length direction along both ends of the winding axis direction. Since it is connected, it can have a current collection structure with low resistance and high current collection efficiency, and is suitably used as a current collection structure for batteries that require relatively large input / output, such as lithium secondary batteries for hybrid vehicles. .

JP 2011-100591 A

  In a square battery using a flat wound electrode group, the electric capacity can be increased by increasing the number of turns of the positive electrode sheet and the negative electrode sheet. The flat thickness increases. Therefore, in order to gather and integrate the metal foil laminated portions of the electrode sheet in the thickness direction, it is necessary to increase the width of the foil exposed portion.

  This is because as the flat thickness of the flat wound electrode group becomes thicker, the distance required to bring the innermost metal foil exposed part of the electrode group into contact with the outermost metal foil exposed part becomes longer. For this reason, unless the width of the exposed portion of the metal foil is sufficiently wide, it is geometrically difficult to gather the exposed portions of the metal foil and connect them integrally to the electrical connection member. On the other hand, if the width of the exposed portion of the metal foil is increased, the dead space in which the mixture layer does not exist inside the battery increases, and the electric capacity of the battery is limited.

  In order to solve such a problem, the winding center part of the metal foil laminated part is expanded, and the metal foil laminated part is divided into two sets for each side in the flat thickness direction, and each is assembled in the thickness direction. Thus, a method of forming a pair of collecting portions and connecting an electrical connection member to each collecting portion can be employed (hereinafter referred to as a split connection method).

  In this split connection method, the thickness of the metal foil laminate on one side is approximately one half of the thickness of the entire flat wound electrode group, and therefore the entire metal foil laminate is assembled. In comparison, the required width of the metal foil laminate can be shortened. Therefore, the dead space can also be reduced, and more electric capacity of the battery can be secured.

  When the split connection method is adopted in the flat wound electrode group, the winding center portion of the positive electrode metal foil laminate portion and the winding center portion of the negative electrode metal foil laminate portion are expanded. The exposed metal foil portion at the start end is exposed to the outside. The winding start end portion of the positive electrode sheet or the negative electrode sheet is located on the innermost circumference of the electrode group, and the metal foil exposed portions are exposed by the expansion of the winding center portion.

  The exposed portion of the metal foil at the starting edge of the electrode sheet can be easily moved if it is not properly fixed.For example, an external force acts to cause unintended displacement, breakage, contact, etc. There is a risk of quality problems. Examples of the external force include an electrolyte flow in an electrolyte injection process and vibration during use of the battery.

  The present invention has been made in view of the above points, and the object of the present invention is a rectangular shape that can prevent the occurrence of quality defects due to the exposed portion of the metal foil at the beginning of the electrode sheet. It is to provide a battery.

  In the prismatic battery of the present invention that solves the above problems, an electrode mixture layer is formed on the surface of a strip-shaped metal foil, and a metal foil exposed portion is formed in which the metal foil is exposed along one long side of the metal foil. A rectangular battery having a flat wound electrode group obtained by winding the electrode sheet into a flat shape, wherein the exposed metal foil exposed portion at the starting edge of the electrode sheet is the outer periphery of the exposed metal foil portion. It is characterized by being fixed to the wound inner peripheral surface of the exposed metal foil portion wound on the side.

  According to the present invention, the exposed metal foil exposed portion at the beginning of the electrode sheet is fixed to the wound inner peripheral surface of the exposed metal foil that is wound on the outer peripheral side of the exposed metal foil portion. Therefore, even when an external force is applied to the exposed portion of the metal foil at the beginning of the electrode sheet, it prevents unintended displacement, breakage, contact, etc. at the beginning of the electrode sheet, and causes a defect in quality. Can be prevented. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

The whole perspective view of the square battery which has a flat winding type electrode group. The disassembled perspective view of the square battery shown in FIG. FIG. 3A is a perspective view of the lid assembly, and FIG. 3B is a cross-sectional view taken along line bb in FIG. 3A. The external appearance perspective view which shows the state which expand | deployed a part of flat winding type electrode group. It is a figure which shows typically the cross section of a flat winding type electrode group, (a) is a general view, (b) is a principal part enlarged view. It is a figure which shows a part of flat-shaped winding type electrode group by a cross section, and is a figure which shows the state before gathering a metal foil laminated part. It is a figure which shows a part of flat winding type electrode group by a cross section, and is a figure which shows the state which assembled the metal foil laminated part to the winding center side. It is a figure which shows a part of flat winding type electrode group by a cross section, and is a cross-sectional schematic diagram which shows the state which divided | segmented the metal foil lamination | stacking part into two at the winding center, and each assembled. It is a figure which shows a part of flat flat type | formula electrode group of 1st Embodiment by a longitudinal cross-section, and is a figure which shows the state before forming a gathering part in a metal foil laminated part. It is a figure which shows a part of flat flat-type electrode group of 1st Embodiment by a longitudinal cross-section, and is a figure which shows a state when forming a gathering part in a metal foil laminated part and connecting it to a connection piece. It is a figure which shows a part of conventional flat winding type electrode group by a longitudinal cross-section, and is a figure which shows the state before forming a gathering part in a metal foil laminated part. It is a figure which shows a part of conventional flat winding type electrode group by a longitudinal cross-section, and is a figure which shows the state which formed the aggregated part in the metal foil laminated part, and was connected to the connection piece. It is a figure explaining the condition which joins the metal foil lamination | stacking part and internal terminal of a flat winding type electrode group, (a) is an ultrasonic welding machine with the assembly part of a metal foil lamination | stacking part, and the connection piece of an internal terminal. Explanatory drawing of the state pinched | interposed, (b) is principal part sectional drawing after welding joining. It is a figure which shows a part of flat flat wound-type electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows the state before forming an aggregate part in a metal foil laminated part. It is a figure which shows a part of flat winding type | formula electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows a state when forming a gathering part in a metal foil laminated part and connecting it to a connection piece. It is a figure which shows a part of flat flat type | formula electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows the state before forming a gathering part in a metal foil laminated part. It is a figure which shows a part of flat winding type | formula electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows a state when forming a gathering part in a metal foil laminated part and connecting it to a connection piece. It is a figure which shows a part of flat flat type | formula electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows the state before forming a gathering part in a metal foil laminated part. It is a figure which shows a part of flat winding type | formula electrode group of 2nd Embodiment by a longitudinal cross-section, and is a figure which shows a state when forming a gathering part in a metal foil laminated part and connecting it to a connection piece.

  Next, an embodiment in which a prismatic battery according to the present invention is applied to a lithium ion secondary battery will be described with reference to the drawings. It should be noted that the scales and aspect ratios of the drawings do not match for the convenience of drawing, and the shapes and dimensions of the parts are the same in the drawings.

<First embodiment>
As shown in FIGS. 1 and 2, the lithium ion secondary battery 1 includes a rectangular container 2 having an opening at one end, and a flat wound electrode group 5 accommodated in the container 2. Has been. The opening of the container 2 is sealed with a lid 11.

  As shown in FIG. 2, the flat wound electrode group 5 that is a power storage element is integrally attached to the lid assembly 4 and constitutes a power storage element assembly 3 together with the lid assembly 4. The lid assembly 4 and the flat wound electrode group 5 are connected to the positive electrode connecting terminal and the negative electrode connecting terminal of the lid assembly 4, and the positive metal foil laminated portion 45 and the negative metal foil laminated portion of the flat wound electrode group 5. 55 are joined and integrated.

  2 and 3, the lid assembly 4 includes a lid 11 that closes the opening of the container 2, a positive external terminal 21 and a negative external terminal 31 that protrude from the upper surface of the lid 11, and these external terminals 21, A positive electrode connection terminal 22 and a negative electrode connection terminal 32 that are electrically connected to 31 are provided. The positive external terminal 21 and the positive connection terminal 22, and the negative external terminal 31 and the negative connection terminal 32 are fixed to the lid 11 while being electrically insulated from the lid 11 by the gasket 12. In addition, the lid 11 is provided with a gas discharge port 13 and a liquid injection port 14 that is an injection port for an electrolytic solution. The liquid injection port 14 is sealed with a liquid injection stopper 15 after the electrolytic solution is injected into the container 2.

  The positive electrode connection terminal 22 is connected to a positive electrode current collector terminal 23 extending from the lid 11 toward the container bottom in the container 2. The positive electrode current collecting terminal 23 includes a base portion 23A extending toward the bottom of the container along the positive electrode side end surface located on one side in the winding axis direction of the flat wound electrode group 5, and a forked portion from both lower end side surfaces of the base portion 23A. And a pair of positive electrode current collecting connection pieces 23B and 23B extending in the container bottom direction. The pair of positive current collecting connection pieces 23 </ b> B and 23 </ b> B are opposed to each other in the thickness direction of the flat wound electrode group 5 and viewed from above the lid 11. It is inclined so that the interval between the connecting pieces becomes narrower as it moves toward the center in the rotational axis direction. The inner surfaces of the respective positive electrode current collecting connection pieces 23B and 23B are brought into contact with and welded to the outermost peripheral surface of the positive electrode metal foil laminated portion of the flat wound electrode group 5.

  Similarly, the negative electrode connection terminal 32 is connected to a negative electrode current collector terminal 33 extending from the lid 11 toward the container bottom in the container 2. The negative electrode current collecting terminal 33 includes a base portion 33A extending toward the bottom of the container along the negative electrode side end surface located on the other side in the winding axis direction of the flat wound electrode group 5, and a forked portion from both lower end side surfaces of the base portion 33A. And a pair of negative electrode current collecting connection pieces 33B and 33B extending in the container bottom direction. The pair of negative electrode current collector connection pieces 33B and 33B is also moved to the center side in the winding axis direction of the flat wound electrode group 5 when viewed from above the lid 11, similarly to the positive electrode current collector connection pieces 23B and 23B. Therefore, it inclines so that the space | interval of connection pieces may become narrow. The inner surfaces of the negative electrode current collector connection pieces 33B and 33B are brought into contact with and joined to the outermost peripheral surface of the negative electrode metal foil laminated portion of the flat wound electrode group 5.

  The pair of positive electrode current collector connection pieces 23B and 23B of the positive electrode current collector terminal 23 are joined to the positive electrode metal foil laminate at the end on one side in the winding axis direction of the flat wound electrode group 5, and the negative electrode current collector terminal The pair of negative electrode current collector connection pieces 33B, 33B of 33 are joined to the negative electrode metal foil laminate at the other end of the flat wound electrode group 5 in the winding axis direction. The positive current collector terminal 23 and the negative current collector terminal 33 sandwich the flat wound electrode group 5 from both sides in the winding axis direction and are integrally supported by the lid 11.

  As shown in FIG. 4, the flat wound electrode group 5 winds the strip-shaped positive electrode sheet 41 and the strip-shaped negative electrode sheet 51 in a flat shape via a strip-shaped separator 61 so as not to contact each other. Consists of. In the present embodiment, the flat wound electrode group 5 uses a plate-shaped core 71 (see, for example, FIG. 5), and is formed into a flat shape by winding around the core 71. Has been.

  The positive electrode sheet 41 has a strip-like positive electrode metal foil 42 made of an aluminum foil or an aluminum alloy foil, and the negative electrode sheet 51 has a strip-like negative electrode metal foil 52 made of a copper foil or a copper alloy foil. The separator 61 is configured by a sheet made of porous polyethylene resin.

  On both surfaces of the positive electrode metal foil 42 of the positive electrode sheet 41, a positive electrode mixture slurry containing a positive electrode active material, a conductive material, and a binder is applied to form a positive electrode mixture layer 43. A negative electrode mixture layer 53 is formed on both surfaces of the negative electrode metal foil 52 of the negative electrode sheet 51 by applying a slurry of a negative electrode mixture containing a negative electrode active material, a conductive material, and a binder.

  The positive electrode sheet 41 is not coated with the positive electrode mixture over a certain width along the long side of one side in the width direction of the positive electrode metal foil 42, and the uncoated electrode sheet 42 is exposed. A positive electrode metal foil exposed portion (positive electrode uncoated portion) 44 is provided. The negative electrode mixture is coated on the negative electrode sheet 51 over a certain width along the longer side of the other side located on the opposite side to the positive electrode metal foil exposed portion 44 of the positive electrode sheet 41 in the winding axis direction. An uncoated negative electrode metal foil exposed portion (negative electrode uncoated portion) 54 from which the negative electrode metal foil 52 is exposed is provided.

  The positive electrode sheet 41 and the negative electrode sheet 51 are formed such that the length of the negative electrode mixture layer 53 in the winding axis direction is longer than the length of the positive electrode mixture layer 43 in the winding axis direction. The winding core 71 is wound around the winding core 71 such that both end positions in the winding axis direction are disposed at positions outside the winding axis direction both ends of the positive electrode mixture layer 43.

  The positive electrode sheet 41 and the negative electrode sheet 51 have a positive electrode metal foil exposed portion 44 disposed on one side in the winding axis direction and a negative electrode metal foil exposed portion 54 disposed on the other side in the winding axis direction. The separator 61 is interposed between the negative electrode mixture layer 53 and laminated around the core 71. Then, the positive electrode metal foil exposed portion 44 is formed in a flat shape on one side of the flat wound electrode group 5 in the winding axis direction, and the positive electrode metal foil laminated portion 45 is formed. On the side, the negative electrode metal foil exposed portion 54 is wound and laminated in a flat shape to form a negative electrode metal foil laminated portion 55.

  The positive electrode metal foil exposed portion 44 of the positive electrode sheet 41 using the aluminum foil as the positive electrode metal foil 42 forms a positive electrode metal foil laminated portion 45, and as shown in FIG. 2, the positive electrode current collector made of aluminum which is an electrical connection member The terminal 23 is connected to the positive current collecting connection piece 23B. And the negative electrode metal foil exposure part 54 of the negative electrode sheet 51 which uses copper foil as the negative electrode metal foil 52 forms the negative electrode metal foil lamination | stacking part 55, and the negative electrode current collection of the copper negative electrode current collection terminal 33 which is an electrical connection member Connected to the connecting piece 33B. The flat wound electrode group 5, the positive electrode current collector terminal 23, and the negative electrode current collector terminal 33 are accommodated in the container 2 with an insulating sheet (not shown) interposed therebetween, and are sealed by the lid 11.

  As shown in FIGS. 5A and 5B, the flat wound electrode group 5 is formed by winding up the positive electrode sheet 41, the negative electrode sheet 51, and the separator 61 around the winding core 71. . The positive electrode metal foil exposed portion 44 of the positive electrode sheet 41 has a center in the winding axis direction in which the positive electrode mixture layer 43 of the positive electrode sheet 41 and the negative electrode mixture layer 53 of the negative electrode sheet 51 are wound with a separator 61 interposed therebetween. It protrudes to the −W direction side, which is one side of the winding axis direction, than the portion, and constitutes the positive electrode metal foil laminated portion 45 centering on the winding core 71. The negative electrode metal foil exposed portion 54 of the negative electrode sheet 51 protrudes to the + W direction side, which is the other side in the winding axis direction, from the central portion in the winding axis direction, and the negative electrode metal foil laminated portion 55 centering on the winding core 71. Is configured.

  6A to 6C are views showing a part of the flat wound electrode group in a cross section, FIG. 6A is a view showing a state before the metal foil laminated portions are assembled, and FIG. 6B is a view showing the metal foil. FIG. 6C is a schematic cross-sectional view showing a state in which the laminated portion is gathered on the winding center side, and FIG. 6C is a sectional view showing a state in which the metal foil laminated portion is divided into two at the winding center. In the following description, the positive electrode side is described, and the negative electrode side is the same as that of the positive electrode side. Therefore, a detailed description thereof is omitted by describing the reference numerals in parentheses.

  For the purpose of increasing the battery capacity or the like, when the number of the positive electrode sheets 41 and the negative electrode sheets 51 is increased to increase the thickness of the flat wound electrode group 5, as shown in FIG. It is geometrically difficult to gather the portions 45 (55) together and connect them together to the electrical connection member. This is because the distance necessary to bring the innermost positive electrode metal foil exposed portion 44 (54) of the flat wound electrode group 5 into contact with the outermost positive electrode metal foil exposed portion 44 (54) becomes longer. is there.

  In the present embodiment, as shown in FIG. 6C, the positive electrode metal foil laminated portion 45 (55) is expanded from the winding center in the thickness direction of the flat wound electrode group 5, and the position of the core 71 The positive electrode metal foil laminated portion 45 (55) is divided into two sets on each side with the winding center as a boundary, and each set is compressed and assembled in the thickness direction, and a pair of positive electrode assembly portions 46 integrated with each other. (56) is formed, and a split connection method is used in which each of the positive current collector terminals 23B (33B) of the positive current collector terminal 23 (33), which is an electrical connection member, is connected. According to this split connection method, the thickness of one side of the positive electrode metal foil laminated portion 45 (55) is approximately one half of the thickness of the entire flat wound electrode group 5, and therefore the positive electrode metal foil Without increasing the width of the exposed portion 44 (45), the exposed portions 44 (45) can be assembled in the thickness direction and integrated to be connected to the pair of positive electrode current collector connection pieces 23B (33B) of the positive electrode current collector terminal 23 (33). .

  7A and 7B are longitudinal cross-sectional views of a part of the flat wound electrode group in the present embodiment cut along the winding core at the winding center along the WH surface, and FIG. FIG. 7B is a diagram showing a state when the aggregate portion is formed in the metal foil laminated portion and the connection portion is connected to the current collecting connection piece.

  As shown in FIG. 7A, the flat wound electrode group 5 in the present embodiment has a starting start edge of the positive electrode sheet 41 (51) on the connection portion 47 (57) of the positive electrode metal foil laminated portion 45 (55). Before winding, the position of the winding start end portion of the positive electrode sheet 41 (51) with respect to the core is adjusted so that the metal foil exposed portion 44A (54A) of the portion is arranged to face.

  Then, as shown in FIG. 7B, the positive electrode metal foil laminate 45 (55) is divided into two sets to form a pair of positive electrode assemblies 46 (56) in the positive metal foil laminate 45 (55). As a result, the exposed metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 (51) faces the positive current collecting connection piece 23B (33B) with the positive electrode collecting portion 46 (56) interposed therebetween. Placed in position.

  And the positive electrode current collection connection piece 23B (33B) of the positive electrode current collection terminal 23 (33) is joined to the connection part 47 (57) of the positive electrode aggregation part 46 (56). As a result, the exposed metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 (51) is joined to the positive electrode collecting portion 46 (56) together with the positive electrode current collecting connection piece 23B (33B). The positive electrode metal foil exposed portion 44A (54A) is fixed to the wound inner peripheral surface of the metal foil exposed portion 44 (54) wound on the outer peripheral side.

  Therefore, even when an external force is applied to the exposed metal foil exposed portion 44A (54A) of the positive electrode sheet 41 (51), unintended displacement or damage of the exposed positive electrode metal foil 44A (54A) It is possible to prevent the occurrence of contact with the part and the like, and to prevent the metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 (51) from causing a quality defect. it can.

  8A and 8B are diagrams for explaining a comparative example. FIG. 8A is a cross-sectional view showing a state before forming the aggregated portion in the metal foil laminated portion, and FIG. 8B is a current collection by forming the aggregated portion in the metal foil laminated portion. It is a cross-sectional schematic diagram which shows a state when it connects with a connection piece.

  In this comparative example, as shown in FIG. 8A, the metal foil exposed portion 44A (54A) at the starting end portion of the positive electrode sheet 41 (51) is connected to the connecting portion 47 (57) of the positive metal foil laminated portion 45 (55). ) Are not arranged to face each other, and are arranged at positions deviating downward in the drawing.

  Therefore, the positive electrode assembly portion 46 (56) is formed in the positive electrode metal foil laminated portion 45 (55), and the positive electrode of the positive electrode current collector terminal 23 (33) is connected to the connection portion 47 (57) of the positive electrode assembly portion 46 (56). Even if the current collector connection piece 23B (33B) is joined, as shown in FIG. 8B, the metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 is not connected to the positive current collector connection piece 23B (33B). At the same time, it is not bonded to the positive electrode assembly portion 46 (56) and is not fixed to the wound inner peripheral surface of the metal foil exposed portion 44 (54) wound on the outer peripheral side of the positive electrode metal foil exposed portion 44A (54A).

  Therefore, the metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 (51) in the flat wound electrode group 5 of the comparative example is in a state in which the position can be easily moved. When an external force is applied to the positive electrode metal foil exposed portion 44A (54A) due to the flow of the electrolyte in the liquid injection process or vibration during use of the battery 1, the positive metal foil exposed portion 44A (54A) is not intended. There is a possibility that displacement, breakage, contact with other parts, etc. may occur, and there is a concern that it may cause quality problems.

  On the other hand, in the present embodiment, as shown in FIG. 7B, the metal foil exposed portion 44A (54A) at the starting end portion of the positive electrode sheet 41 (51) has a positive current collecting connection piece 23B (33B). At the same time, the metal foil exposed portion 44 (which is joined and integrated with the connecting portion 47 (57) of the positive electrode assembly portion 46 (56) and wound around the outer peripheral side of the positive metal foil exposed portion 44A (54A). 54), it is possible to prevent the metal foil exposed portion 44A (54A) at the beginning of winding of the positive electrode sheet 41 from being a cause of quality problems.

The manufacturing process of the lithium ion secondary battery 1 as described above will be described.
First, the lid assembly 4 and the flat wound electrode group 5 are integrated to manufacture the power storage element assembly 3 shown in FIG. 2, and the power storage element assembly 3 is inserted into the container 2. Then, the lid 11 is laser welded to the container 2 to seal the opening of the container 2, and then an electrolytic solution (not shown) is injected into the container 2 from the liquid injection port 14. After injecting the electrolyte, the injection port 14 is sealed with an injection plug 15 and laser welding is performed. A gasket 12 made of an insulating resin is attached to the positive electrode connection terminal 22 and the negative electrode connection terminal 32 and is electrically insulated from the lid 11, and at the same time, between the positive electrode connection terminal 22 and the negative electrode connection terminal 32 and the lid 11. Sealing liquid has been made. The gas discharge port 13 is provided with a cleavage valve (not shown), which is broken when the internal pressure of the container 2 rises and discharges the internal gas to the outside of the container 2.
Next, the assembly procedure of the electricity storage element assembly 3 will be described.

  First, the flat wound electrode group 5 shown in FIG. 4 is created. The separator 61 is wound around the rectangular flat core 71 at least once, and the positive electrode sheet 41 and the negative electrode sheet 51 are laminated while being insulated by the separator 61 and wound. At that time, the metal foil exposed portion portion of each of the starting end portions of the positive electrode sheet 41 and the negative electrode sheet 51 at a position set in advance with respect to the core 71 as a position arranged to face the connection portions 47 and 57. The positions of the rolling start end portions of the positive electrode sheet 41 and the negative electrode sheet 51 are adjusted so that 44A and 54A are arranged. The separator 61 on the outermost surface of the flat wound electrode group 5 is locked with a tape (not shown).

  Next, the positive electrode metal foil laminated portion 45 and the negative electrode metal foil laminated portion 55 of the flat wound electrode group 5 are expanded in the flat thickness direction of the flat wound electrode group 5 at the respective winding center portions. The metal foil laminated portions 45 and 55 are divided into two sets on each side with the winding center as a boundary, and each set is compressed and assembled in the thickness direction, and a part of each metal foil laminated portion 45 and 55 Then, a pair of integrated portions 46 and 56, which are integrated with each other, are formed (see FIG. 6C).

  And while inserting the positive electrode metal foil lamination | stacking part 45 of the flat wound type electrode group 5 between a pair of positive electrode current collection connection pieces 23B and 23B of the positive electrode current collection terminal 23, it is a pair of negative electrode of the negative electrode current collection terminal 33 The negative electrode metal foil laminated portion 55 of the flat wound electrode group 5 is inserted between the current collecting connection pieces 33B and 33B, and the inner surface 23C of each positive current collecting connection piece 23B and 23B of the positive current collecting terminal 23 is inserted. , 23C, and the outer surfaces of the positive electrode collecting portions 46, 46 of the positive electrode metal foil laminated portion 45 are opposed to each other, and the inner surfaces 33C, 33C of the negative electrode current collecting connection pieces 33B, 33B of the negative electrode current collecting terminal 33 are The outer surfaces of the negative electrode assembly portions 56, 56 of the metal foil laminated portion 55 are opposed to each other.

  As shown in FIG. 9, between the transducer WH (horn) and the stator WA (anvil) of the ultrasonic bonding apparatus, one positive electrode assembly portion 46 and the positive electrode current collector connection piece 23 </ b> B facing the positive electrode assembly portion 46 are provided. Then, the positive electrode current collecting connection piece 23B of the positive electrode current collecting terminal 23 is ultrasonically bonded to the connecting portion 47 of the positive electrode collecting portion 46. At this time, since the metal foil exposed portion 44A at the starting end of the positive electrode sheet 41 is disposed at a position facing the positive electrode current collector connection piece 23B with the positive electrode assembly portion 46 therebetween, The metal foil exposed portion 44A at the beginning of rolling can be joined and integrated with the positive electrode collecting portion 46 together with the positive electrode current collector connection piece 23B, and is wound around the outer periphery of the positive metal foil exposed portion 44A. It can be fixed to the wound inner peripheral surface of the exposed metal foil 44.

  And although illustration is abbreviate | omitted, also about the negative electrode sheet | seat 51, similarly between one vibrator | oscillator WH (horn) and stator WA (anvil) of an ultrasonic bonding apparatus, one negative electrode assembly part 56 and this are opposed. The negative electrode current collector connection piece 33B is sandwiched, and the negative electrode current collector connection piece 33B of the negative electrode current collector terminal 33 is ultrasonically bonded to the connection part 57 of the negative electrode aggregate part 56. At this time, since the metal foil exposed portion 54A at the starting end of the negative electrode sheet 51 is disposed at a position facing the negative electrode current collector connection piece 33B with the negative electrode assembly portion 56 interposed therebetween, The exposed metal foil exposed portion 54A at the beginning of the winding can be joined and integrated with the negative electrode collecting portion 56 together with the negative electrode current collector connection piece 33B, and is wound around the outer periphery of the negative electrode metal foil exposed portion 54A. It can be fixed to the wound inner peripheral surface of the exposed negative electrode metal foil 54.

  The other positive electrode current collector connection piece 23B and the positive electrode assembly portion 46 facing this, and the other negative electrode current collector connection piece 33B and the negative electrode assembly portion 56 opposite thereto are also used in the transducer WH using an ultrasonic bonding apparatus. (Horn) and stator WA (anvil) are sandwiched and ultrasonically bonded to each other.

  Through the above assembling procedure, the positive electrode metal foil laminated portion 45 exposed on the side end surface on one side in the winding axis direction of the flat wound electrode group 5 is joined and integrated with the positive electrode current collector terminal 23. Although not shown, the negative electrode metal foil laminated portion 55 exposed on the side end surface on the other side in the winding axis direction of the flat wound electrode group 5 is joined and integrated with the negative electrode current collector terminal 33. . Accordingly, the flat wound electrode group 5 is electrically connected to the positive current collector terminal 23 and the negative current collector terminal 33, respectively.

  In the manufacturing process described above, the exposed portion of the metal foil at the beginning of the winding of the positive electrode sheet 41 at a position set in advance with respect to the core 71 as the position arranged facing the connection portion 47 of the positive electrode assembly portion 46. 44A is disposed, and the metal foil exposed portion 54A at the beginning of the rolling of the negative electrode sheet 51 at a position set in advance with respect to the winding core 71 as a position disposed opposite to the connection portion 57 of the negative electrode assembly 56. And winding the positive electrode sheet 41 and the negative electrode sheet 51 on the winding core 71 via a separator 61 therebetween to form the flat wound electrode group 5, and the winding of the flat wound electrode group 5 The winding center portions of the positive electrode metal foil laminate portion 45 and the negative electrode metal foil laminate portion 55 located on both end faces in the rotation axis direction are expanded in the flat thickness direction, respectively, and the winding start end portions of the positive electrode sheet 41 and the negative electrode sheet 51 are spread. Metal foil exposed portion 44A, 54A Each of the exposing step and the metal foil exposed portion 44A at the beginning of rolling of the positive electrode sheet 41 are joined and integrated with the connecting portion 47 of the positive electrode collecting portion 46 together with the positive electrode current collecting connecting piece 23B, and the negative electrode sheet A step of joining and integrating the exposed metal foil exposed portion 54A at the beginning of 51 with the connecting portion 57 of the negative electrode collecting portion 56 together with the negative electrode current collecting connecting piece 33B.

  According to the prismatic battery 1 in the present embodiment described above, the metal foil exposed portions 44A and 54A at the starting end portions of the positive electrode sheet 41 and the negative electrode sheet 51 are placed on the outer peripheral side of the metal foil exposed portion portions 44A and 54A. Since it is fixed to the wound inner peripheral surface of the rotated metal foil exposed portions 44 and 54, an external force has acted on the metal foil exposed portion portions 44A and 54A at the beginning of winding of the positive electrode sheet 41 and the negative electrode sheet 51. Even in this case, unintentional displacement, breakage, contact, etc. are prevented from being caused on the metal foil exposed portion 44A, 54A at the starting end of the positive electrode sheets 41, 51, and this portion causes a quality defect. Can be prevented.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, about the component similar to 1st Embodiment, the detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  What is characteristic in the present embodiment is that the fixing members 81 and 91 are arranged on the innermost peripheral surface of the positive electrode metal foil exposed portion 44 and the innermost peripheral surface of the negative electrode metal foil exposed portion 54 of the flat wound electrode group 5. The wound inner peripheral surface of the positive electrode metal foil exposed portion 44 and the negative electrode metal foil are wound around the outer peripheral side of the metal foil exposed portion portions 44A and 54A at the winding start end portions of the positive electrode sheet 41 and the negative electrode sheet 51. It is fixing to the winding inner peripheral surface of the exposed part 54.

  The positive electrode fixing member 81 is opposed to a part of the innermost peripheral surface of the positive electrode metal foil exposed portion 44 over a predetermined length range including the positive electrode metal foil exposed portion portion 44 </ b> A at the starting start portion of the positive electrode sheet 41. It consists of the plate-shaped member arrange | positioned. Similarly, the negative electrode fixing member 91 also covers a predetermined length range including the negative electrode metal foil exposed portion 54A at the beginning of the negative electrode sheet 51 at a part of the innermost peripheral surface of the negative electrode metal foil exposed portion 54. It consists of the plate-shaped member arrange | positioned facing each other. The positive electrode fixing member 81 is made of a thin plate made of the same kind of metal that can be welded to the positive electrode metal foil laminated portion 45, and the negative electrode fixing member 91 is made of a thin plate made of the same kind of metal that can be welded to the negative electrode metal foil laminated portion 55. Has been.

  The positive electrode fixing member 81 is brought into contact with the innermost peripheral surface of the positive electrode metal foil exposed portion 44 when the connecting portion 47 of the collecting portion 46 and the positive electrode current collecting connecting piece 23B are ultrasonically bonded. It is used as a contact plate to be ultrasonically bonded together with the positive electrode current collector connection piece 23B. Similarly, the negative electrode fixing member 91 is brought into contact with the innermost peripheral surface of the negative electrode metal foil exposed portion 54 when the connecting portion 57 of the collecting portion 56 and the negative electrode current collecting connecting piece 33B are ultrasonically bonded. It is used as a backing plate that is ultrasonically bonded together with the part 56 and the negative electrode current collector connection piece 33B.

  10A and 10B are diagrams for explaining an example in the present embodiment, and are diagrams corresponding to FIGS. 7A and 7B.

  The positive electrode fixing member 81 (91) has a size and shape that is substantially the same as or slightly larger than that of the connecting portion 47 (57) of the collecting portion 46 (56), and ultrasonic waves are applied to the connecting portion 47 (57) over almost the entire surface. Be joined. As a result, the exposed metal foil exposed portion 44A (54A) of the positive electrode sheet 41 (51) is sandwiched between the positive electrode fixing member 81 (91) and the positive electrode assembly portion 46 (56). It is joined and integrated with the positive electrode current collector connection piece 23B (33B). Therefore, the exposed metal foil exposed portion 44A (54A) at the beginning end of the positive electrode sheet 41 (51) is wound around the outer periphery of the positive metal foil exposed portion 44A (54A). 54).

  FIG. 11A and FIG. 11B are diagrams for explaining another example of the present embodiment. The positive electrode fixing member 81 (91) may not be ultrasonically bonded over substantially the entire surface. For example, as shown in FIG. 11A and FIG. 11B, the winding direction of the flat wound electrode group 5 from the cathode metal foil exposed portion 44A (54A) at the beginning of winding of the positive electrode sheet 41 (51) Both the first region portion arranged on the winding direction direction side and the second region portion arranged on the winding reverse direction side which is the direction opposite to the winding direction of the flat wound electrode group 5 are connected to each other. It is good also as a structure which is ultrasonically joined to the part 47A (57A) and 47B (57B), and fixes to an innermost peripheral surface. Even in such a configuration, the metal foil exposed portion 44A (54A) at the starting edge of the positive electrode sheet 41 (51) is wound around the outer periphery of the positive metal foil exposed portion 44A (54A). It is fixed to the wound inner peripheral surface of the foil exposed portion 44 (54).

  12A and 12B are diagrams illustrating still another example of the present embodiment. The positive electrode fixing member 81 (91) is a winding forward direction which is the winding direction of the flat wound electrode group 5 from the positive electrode metal foil exposed portion 44A (54A) at the beginning of winding of the positive electrode sheet 41 (51). Of the first region disposed on the side and the second region disposed on the winding reverse direction side that is opposite to the winding direction of the flat wound electrode group 5, only the second region is The connecting portion 47 (57) is ultrasonically bonded and fixed to the innermost peripheral surface. According to such a configuration, the wound inner peripheral surface of the metal foil exposed portion 44 (54) wound around the outer peripheral side of the positive electrode metal foil exposed portion 44A (54A) and the first of the positive electrode fixing member 81 (91). The metal foil exposed portion 44A (54A) at the beginning of the rolling of the positive electrode sheet 41 (51) can be sandwiched between the region 1 and the region of the positive electrode metal foil exposed portion 44A (54A). It can fix to the winding inner peripheral surface of the rotating metal foil exposed part 44 (54).

  According to the configuration of the prismatic battery 1 in the above-described embodiment, by using the positive electrode fixing members 81 and 91, the metal foil exposed portions 44 </ b> A and 54 </ b> A at the starting end portions of the positive electrode sheet 41 and the negative electrode sheet 51 are arranged on the outer circumference It can be simply and reliably fixed to the wound inner peripheral surface of the positive electrode metal foil exposed portion 44 wound on the side and the wound inner peripheral surface of the negative electrode metal foil exposed portion 54.

  Further, when the connecting portion 47 (57) of the positive electrode collecting portion 46 (56) and the positive electrode current collecting connecting piece 23B (33B) are ultrasonically bonded, the positive electrode current collecting connecting piece 23B via the positive electrode collecting portion 46 (56). When the contact plate is used at a position opposed to (33B), the metal foil exposed portion 44A (54A) at the starting end of the positive electrode sheet 41 (51) is moved to the positive metal foil exposed portion by the contact plate. Since it can fix to the winding inner peripheral surface of the metal foil exposed portion 44 (54) wound around the outer peripheral side of the portion 44A (54A), it is not necessary to prepare a new fixing member, and the present invention is easily implemented. can do.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. For example, in the above-described embodiment, the case where the core is used has been described as an example. However, the core is not essential and the core may not be used.

  The above description is an embodiment, and the present invention can be applied to prismatic storage batteries having various structures without departing from the spirit of the present invention, and can be applied not only to lithium ion secondary batteries but also to capacitors. It is. In the above-described embodiment, an example of a rectangular lithium ion secondary battery is shown as the rectangular battery, so that the power storage element assembly 3 is used. However, in the case of a primary battery instead of a secondary battery, a power generation element assembly is obtained. Of course.

DESCRIPTION OF SYMBOLS 1 Square battery 5 Flat winding type electrode group 23 Positive electrode current collection terminal 23B Positive electrode connection piece 33 Negative electrode current collection terminal 33B Negative electrode connection piece 41 Positive electrode sheet (electrode sheet)
42 positive electrode metal foil 43 positive electrode mixture layer (electrode mixture layer)
44 Positive Metal Foil Exposed Portion 44A Metal Foil Exposed Portion 45 at the Starting Edge of the Positive Electrode Sheet 45 Positive Metal Foil Laminated Portion 46 Aggregation Portion 47 Connection Portion 51 Negative Electrode Sheet (Electrode Sheet)
52 Negative electrode metal foil 53 Negative electrode mixture layer (electrode mixture layer)
54 Negative Metal Foil Exposed Portion 54A Negative Foil Exposed Metal Foil Exposed Portion 55 Negative Electrode Metal Foil Laminated Portion 56 Assembly Portion 57 Connection Portion 61 Separator 71 Core

Claims (8)

A flattened electrode sheet in which an electrode mixture layer is formed on the surface of a strip-shaped metal foil and a metal foil exposed portion in which the metal foil is exposed is formed along one long side of the metal foil. A prismatic battery having a wound electrode group,
The metal foil exposed part of the electrode sheet starting end is fixed to the wound inner peripheral surface of the metal foil exposed part wound on the outer peripheral side of the metal foil exposed part,
An electrical connection member electrically connected to the exposed portion of the metal foil of the flat wound electrode group;
In the flat wound electrode group, the exposed portion of the metal foil exposed at the beginning of the electrode sheet is disposed opposite the connecting portion of the exposed portion of the metal foil connected to the electrical connecting member. And
The flat wound electrode group is wound at the winding axial direction end and expanded in the flat thickness direction at the winding central portion of the metal foil exposed portion, and at least one of the flat wound electrode groups has a flat thickness. A prismatic battery characterized in that the connecting portion is provided in a collecting portion assembled in a direction. The electrical connection member has a current collector connection piece connected to the connection portion,
In the flat wound electrode group, the exposed metal foil exposed portion at the beginning of the electrode sheet is disposed at a position facing the current collector connecting piece with the collecting portion in between. The prismatic battery according to claim 1 , wherein 3. The prismatic battery according to claim 2 , wherein the exposed portion of the metal foil at the starting end portion of the electrode sheet is joined to and integrated with the connecting portion of the collecting portion together with the current collecting connecting piece. . Claims provided at the innermost circumferential surface of the metal foil exposed portion, and having a fixing member for fixing the metal foil exposed portion of the firewood starting end of the electrode sheet to the wound in the peripheral surface 2. The square battery according to 2 . 5. The prismatic battery according to claim 4 , wherein the fixing member is joined and integrated together with the exposed portion of the metal foil at the starting end portion of the electrode sheet and the connecting portion of the assembly portion. The fixing member is disposed so as to be opposed to a part of the innermost peripheral surface of the exposed metal foil portion over a predetermined length range including the exposed metal foil exposed portion portion of the electrode sheet. Both of the first region portion disposed on the winding forward direction side and the second region portion disposed on the winding reverse direction side from the exposed portion of the metal foil at the winding start end portion of the electrode sheet. The prismatic battery according to claim 4 , wherein each of the prismatic batteries is fixed to the innermost peripheral surface. The fixing member is disposed so as to be opposed to a part of the innermost peripheral surface of the exposed metal foil portion over a predetermined length range including the exposed metal foil exposed portion portion of the electrode sheet. Of the second region portion disposed on the winding reverse direction side and the first region portion disposed on the winding forward direction side from the metal foil exposed portion portion of the starting start portion of the electrode sheet, The prismatic battery according to claim 4 , wherein the first region portion is fixed to the innermost peripheral surface. An electrode sheet in which an electrode mixture layer is formed on the surface of a strip-shaped metal foil and a metal foil exposed portion in which the metal foil is exposed along one long side of the metal foil is formed on a plate-shaped core. A method of manufacturing a prismatic battery having a rotated flat wound electrode group,
The metal foil exposed portion at the starting end of the electrode sheet at a position preset with respect to the core as the position where the connecting portion of the metal foil exposed portion connected to the electrical connecting member is opposed to the electrical connecting member Winding the electrode sheet by placing a part, forming a flat wound electrode group; and
Maki start end of the electrode sheet is expanded to flattened thickness direction winding center portion of the being wound is in stacked by winding axis direction end portion of the flat-shaped wound type electrode assembly wherein the metal foil exposed portion Exposing the exposed portion of the metal foil of the part;
A step of joining and integrating the exposed portion of the metal foil at the starting end of the electrode sheet together with the connecting portion of the exposed portion of the metal foil together with the electrical connecting member. Production method.

Images