JP3629171B2 - Electrode wound type battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode winding type battery having an electrode body in which a positive electrode and a negative electrode are wound, and particularly to an electrode winding type battery characterized by a current collecting structure.
[0002]
[Prior art]
With the downsizing of notebook computers and mobile phones, high-performance batteries such as lithium ion secondary batteries have been developed in the fields of information-related equipment and communication-related equipment, and have already been put into practical use. As a battery such as a lithium ion secondary battery, an electrode winding type battery including an electrode body in which a positive electrode and a negative electrode are wound through a separator is a common form. On the other hand, in the field of automobiles due to environmental problems and resource problems, the development of electric vehicles and hybrid electric vehicles has progressed, and it is considered to use high-performance batteries such as lithium ion secondary batteries as power sources for driving these electric vehicles Has been.
[0003]
A battery used for an electric vehicle driving power source or the like has a large capacity, so that the battery becomes large. When the above-described electrode winding type battery is adopted, a sheet-like electrode having a large area is required. However, in order to satisfy the characteristics of high output, it is necessary to provide a plurality of current collecting leads from a sheet-like electrode in order to efficiently collect current from a wide area electrode to a terminal.
[0004]
This lead is provided by forming one end of the belt-like electrode in the width direction as an electrode mixture unformed portion, and cutting or joining a strip-shaped lead to the unformed portion.
[0005]
The electrode body formed by winding the electrode on which this lead is formed is such that a plurality of leads are irregularly formed from the end surface (winding end surface) in the winding central axis direction of the electrode body (see FIG. 14a). ).
[0006]
These leads are joined and collected to the current collecting member by various methods and are electrically connected to the external terminals of the battery. However, as described above, these leads are irregularly formed. Therefore, it is not easy to collect them together.
[0007]
As a conventional current collecting member and lead processing method, for example,
(1) In Japanese Patent Laid-Open No. 9-92335, there is a lead current collecting system in which a cylindrical current collecting member is provided on a wound end face of an electrode body, and a lead is joined to the cylindrical side surface of the current collecting member. It is disclosed (see FIG. 15).
[0008]
(2) Further, in Japanese Patent Laid-Open No. 10-64588, a winding core that protrudes from the electrode body winding end surface when winding the positive electrode and the negative electrode is used, and the protruding portion of the winding core is used as a current collecting member. Yes. A lead current collecting system is disclosed in which the leads are joined so as to be gathered to the protruding portion of the wound core (see FIG. 14b). In this wound core, the positive electrode side and the negative electrode side are electrically insulated.
[0009]
[Problems to be solved by the invention]
However, the above prior art has the following drawbacks.
[0010]
The method of using the separate cylindrical current collecting member of (1) above requires an area for joining the lead to the cylindrical side surface of the current collecting member, and the height of the cylindrical current collecting member is increased accordingly. Since it is necessary, the volume occupied by the current collecting member inside the battery is increased, and the volume energy density of the battery is reduced.
[0011]
In the method of joining the lead to the wound core obtained by winding the electrode etc. in (2) above, the wound core is an essential member, and the weight energy density of the entire battery is lowered by the weight of the wound core, and the lead is simultaneously connected. The energy weight density of the battery is reduced due to the weight of the protruding portion for bonding, and the winding core needs to protrude to some extent in order to bond the lead from the electrode body, so this portion becomes a dead space. There is a disadvantage that the volume energy density is lowered.
[0012]
The present invention has been made in order to solve the above-described drawbacks in joining a plurality of current collecting leads employed in a relatively large battery to a current collecting member. It aims at providing the electrode winding type battery which makes the current collection system from the system excellent in energy weight density and energy volume density.
[0013]
[Means for Solving the Problems]
That is, the electrode winding type battery of the present invention is formed at one end in the width direction of an electrode body formed by laminating and winding a belt-like positive electrode and a negative electrode, and at least one of the positive electrode and the negative electrode. In an electrode wound battery having a plurality of strip-shaped current collecting leads, the electrode body is disposed substantially parallel to at least one wound end surface on which the leads of the electrode body are formed.And a hole is formedOne or more lead current collecting plates are provided, and the lead is bent in the radial direction of the electrode body.To focus on the winding center and pass through the hole of the lead current collector plate, Each of the leads is parallel to the surface of the current collector plateBent radially outward withA parallel portion, wherein at least part of the parallel portion of the lead current collector plateOpposite to the electrode bodyIt is characterized by being bonded to the surface.
[0014]
That is, the electrode wound battery of the present invention has a relatively thin lead current collecting plate as a current collecting member, and the lead current collecting plate isHas a hole andAt least a part of a lead that is disposed substantially parallel to the wound end face of the electrode body and has a parallel portion bent in parallel with the lead current collector plate is joined to the lead current collector plate. Even if such a lead current collecting plate has a relatively small thickness, it sufficiently functions as a current collecting member. Therefore, even if a plurality of leads are joined, no extra space is required.In addition, the lead is bent once in the radial direction, converged to the winding center, passed through the hole of the lead current collector plate, and then radially parallel to the outer side of the lead current collector plate. Since at least a part is bonded to the surface on the opposite side, the bonding can be easily performed without providing a gap between the lead and the lead current collector plate.Therefore, it is possible to reduce the volume in the battery, which has conventionally been required for the current collecting member in the current collecting process for a large number of leads, and to increase the volume energy density of the battery, and to provide more current collecting leads. Is possible. Moreover, since a winding core is not essential for current collection, the winding core can be eliminated, the weight can be reduced, and the energy weight density of the battery can be increased.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electrode wound battery of the present invention will be described based on embodiments. The electrode wound battery of the present invention is not limited to the following embodiment. Further, for convenience, this battery will be described taking a lithium ion secondary battery as an example. However, the battery of the present invention is an electrode winding type battery having an electrode body formed by winding a belt-like positive electrode and a negative electrode in a spiral shape. It does not matter which type of battery it is.
[0016]
Further, the current collecting member structure characterized by the electrode wound battery according to the present invention is an electric double layer capacitor having an electrode in which an electrode mixture containing activated carbon as an active material is formed in a layer shape on the surface of the current collector. In this specification, “battery” includes the meaning of “capacitor”.
[0017]
In addition, about drawing, since only the principal part is represented typically, it does not express correctly about the shape of a detail, a reduced scale, etc.
[0018]
(Reference embodiment)
FIG. 1 shows an electrode wound battery according to the present invention.UnderstandingofBe helpfulAn overall view of a cylindrical lithium ion secondary battery according to one embodiment is shown, and FIG. 2 is a sectional view of the electrode wound battery according to this embodiment. FIG. 1 shows the battery without a part of the case, and shows the external terminal and the case lid, and the case lid and the case main body being not fixed.
[0019]
In the electrode wound battery of the present embodiment, the current collecting method that is a feature of the electrode wound battery of the present invention is applied to both the positive electrode and the negative electrode. A known current collecting method may be applied to the other side of the electrode winding type battery current collecting method of the invention. However, it can be set as the battery which has the more excellent energy density by applying to both electrodes.
[0020]
The electrode winding type battery of this embodiment has an electrode body 30 in which a positive electrode 33 and a negative electrode 34 are wound through a separator 35, and the electrode body 30 is inserted into a cylindrical case 10. It is configured. The shape of the electrode body 30 of the electrode wound battery according to the present embodiment is cylindrical, and has a diameter of 50 mm and a length of 65 mm. Here, the electrode body 30 refers to a power generation (storage) element of a battery, which is a battery content formed by winding a positive electrode 33 and a negative electrode 34.
[0021]
The battery electrode body or battery case of the present invention is not limited to a cylindrical shape, and may be a cylindrical battery having an elliptical or polygonal cross section.
[0022]
In the electrode wound battery of the present embodiment, the current collecting leads 31 and 32 are formed from the end face (winding end face 30a) where the positive electrode 33 and the negative electrode 34 of the electrode body 30 are wound to form a layered structure. A plurality are formed. When forming both positive and negative current collecting leads, the lead processing becomes complicated, so the electrodes are formed so as to be located on different winding end faces 30a. The lead current collecting plates 21 and 22 are preferably arranged in parallel with the wound end face 30a. This is because if the lead current collecting plate is disposed parallel to the winding end face, the dead space is reduced. However, when it is necessary for other reasons, for example, a problem in processing, a problem in the function of the battery, or the like, it may be slightly out of parallel.
[0023]
The leads 31 and 32 of the electrode winding type battery of the present embodiment are disposed outside in the radial direction of the winding end surface 30a of the electrode body 30 so as to have a parallel portion parallel to the surfaces of the lead current collector plates 21 and 22. It is bent so as to face, and is joined so as to be electrically connected to the surface on the electrode body side of each of the lead current collecting plates 21 and 22 for the positive electrode and the negative electrode. The parallel portions of the leads 31 and 32 may be joined to the lead current collector plates 21 and 22 as long as at least a part of the parallel portions is joined. It is preferable from the viewpoint of an increase in adhesive strength and a decrease in internal resistance that the joint portions between the leads 31 and 32 and the lead current collecting plates 21 and 22 in parallel are larger in area. The direction of bending the lead of the battery of the invention may be either the center direction or the outer direction of the winding end surface as long as it is a radial direction perpendicular to the winding center axis of the winding end surface of the electrode body. The number of times of bending may be any number.
[0024]
The lead current collecting plates 21 and 22 of the electrode wound battery of the present embodiment are electrically connected to the external terminals 41 and 42, respectively.
[0025]
The case 10 of the electrode wound battery according to the present embodiment seals the battery contents from the outside. The case 10 has a shape that matches the electrode body, and includes case lids 11 and 12 and a case body 13. The external terminals 41 and 42 are electrically insulated and fixed to the case lids 11 and 12, respectively.
[0026]
Hereinafter, each component will be described including its manufacturing method.
[0027]
FIG. 3 shows the appearance of the electrode body 30 of the electrode wound battery according to this embodiment.
[0028]
The electrode body is formed by winding a positive electrode, a negative electrode, and the like. A method for forming an electrode body by winding a positive electrode, a negative electrode, and the like will be described. In the present embodiment, as shown in FIG. 4, the positive electrode 33, the negative electrode 34, and the separator 35 are wound around the wound core 36, and then the wound core 36 is removed to form the electrode body 30. The winding core 36 is preferably removed in view of the energy weight density of the battery after winding the electrode or the like to form the electrode body. However, the winding core may be left on the electrode body by using a lightweight winding core. In this case, it is preferable in terms of energy volume density that the wound core does not protrude from the wound end face of the electrode body. Further, if a wound core is not required when forming the electrode body, it is possible not to use it from the beginning.
[0029]
As shown in FIG. 4, the shape of each electrode of the positive electrode 33 and the negative electrode 34 used in the electrode winding type battery of the present embodiment is such that the active material is applied to the surfaces of the positive electrode current collector and the negative electrode current collector made of metal foil. It is a belt-like material having a positive electrode mixture layer 33a and a negative electrode mixture layer 34a each including a positive electrode mixture and a negative electrode mixture formed in layers. The length, width, and electrode area of the electrode are determined by the required battery capacity and shape. In the case where priority is given to either the battery shape or the battery capacity, the length of the electrode or the like is determined in accordance with a condition in which either the battery capacity or the shape is given priority.
[0030]
The method for producing the positive electrode 33 and the negative electrode 34 is not particularly limited, but in the case of a lithium ion secondary battery, in general, the positive electrode 33 is formed by applying a positive electrode mixture in layers on both sides of the positive electrode current collector, After drying, it is cut into a predetermined size, and further compressed by a press to increase the density of the positive electrode mixture layer 33a as necessary. Similarly, in the negative electrode 34, the negative electrode mixture is applied in layers on both sides of the negative electrode current collector, dried, and then cut into a predetermined size and the density of the negative electrode mixture layer 34a is set as necessary. It is made by compressing with a press to increase it.
[0031]
In the case of a lithium ion secondary battery, the positive electrode current collector is preferably an aluminum foil or the like because of electrochemical requirements, and the negative electrode current collector is preferably a copper foil or the like. The thickness of the current collector is preferably about 5 to 30 μm.
[0032]
For example, in a lithium ion secondary battery, the positive electrode mixture is LiCoO as a positive electrode active material.₂, LiNiO₂, LiMn₂O₄A lithium transition metal composite oxide powder such as carbon black is used, and a carbon material powder such as carbon black as a conductive material and polyvinylidene fluoride (PVDF) as a binder are mixed with this positive electrode active material as a dispersion medium. It can be prepared by adding an appropriate amount of N-methyl-2-pyrrolidone (NMP) or the like to make a paste. The negative electrode mixture is, for example, a powder of carbon material such as graphite or coke as the negative electrode active material, and PVDF or the like as a binder is mixed with this negative electrode active material, and NMP or the like as a dispersion medium, as in the positive electrode It can be prepared by adding a suitable amount to make a paste. The means for forming the positive electrode mixture layer and the negative electrode mixture layer, that is, the coating method is not particularly limited, and a known method can be used. The electrode mixture layer is preferably formed on both sides of the current collector in consideration of efficiency. The thickness of the electrode mixture layer on the current collector surface is preferably about 30 to 150 μm per side.
[0033]
As shown in FIG. 4, in the electrode wound battery of the present embodiment, the positive electrode 33 and the negative electrode 34 are respectively positive electrodes in which the positive electrode mixture layer 33a and the negative electrode mixture layer 34a are not formed at one end in the width direction. A composite material layer non-formed part 33b and a negative electrode composite material layer non-formed part 34b are provided, and the positive electrode composite material layer non-formed part 33b and the negative electrode composite material layer non-formed part 34b include a lead 31 for current collection, 32 are respectively joined. The positive electrode mixture layer unformed portion 33b and the negative electrode mixture unformed portion 34b are provided at one end in the width direction. The shapes of the positive electrode mixture layer non-formed part and the negative electrode composite layer non-formed part are not limited to those shown in FIG. 4 and may be any shape as long as the leads can be joined.
[0034]
The leads 31 and 32 of the electrode winding type battery of this embodiment have a length of 50 mm and a width of 10 mm, and a total of 80 leads per one side of the winding end surface 30 a of the electrode body 30. The length of the lead is the total length of the portion protruding from the electrode body and the portion joined to the electrode in the electrode body. The protruding portion of the lead needs to be long enough to be joined to the lead current collector after the lead is bent. Moreover, the part joined to the electrode needs to be long enough to be joined to the electrode. If the length of the lead is longer than the total of these lengths, the lead current collector plate can be separated from the wound end surface of the electrode body by the length of the extra lead, and the gap between the lead and the lead current collector plate There is an advantage that the workability after joining is improved. The width of the lead is preferably wide from the viewpoint of reducing the internal resistance of the battery, and is preferably somewhat narrow from the viewpoint of workability when the lead is bent and joined. Since the battery of the present invention can be provided with a large number of leads, if the lead width cannot be more than a certain width from the viewpoint of workability of the lead, the number of leads can be increased to reduce the internal resistance of the battery. Can respond.
[0035]
Since the leads 31 and 32 are joined to the positive electrode mixture layer non-formed portion 33b and the negative electrode mixture layer non-formed portion 34b, respectively, the leads 31 and 32 have good bonding properties with the positive electrode current collector and the negative electrode current collector, respectively, and are electrochemical. It is desirable that the material be stable. In this embodiment, since it is a lithium ion secondary battery, since aluminum is generally used for the positive electrode current collector, the lead 31 on the positive electrode side to be joined is formed of an aluminum-based material or the like. In addition, since copper is generally used for the negative electrode current collector, the negative electrode side lead 32 is preferably formed of a copper-based material or the like. The lead has a strip shape. The lead is formed at one end in the width direction of the electrode by joining the electrode such that a part or all of the lead in the longitudinal direction protrudes from the electrode body, or by cutting out the electrode.
[0036]
In the present embodiment, the shape of the lead current collector plates 21 and 22 is a disk having substantially the same diameter as the wound end surface 30a of the electrode body 30, and the center part of the disk is cut away, leaving the peripheral part where the lead is joined. An annular shape (diameter 40 mm, thickness 1 mm). The shape of the lead current collector plate needs to have a sufficient area for joining the leads. However, the area is preferably as small as possible in order to reduce the weight and volume of the electrode wound battery. Also, the thickness of the lead current collecting plate is preferably set to a minimum thickness that can maintain the strength required for processing and use. The lead current collecting plate of the electrode wound battery according to the present embodiment has an annular shape based on the shape of the wound end face 30a of the electrode body 30 and the lead joining method as described above. It is determined in accordance with the lead arrangement shape which changes depending on the shape of the 30 winding end faces 30a. For example, when the electrode body is a quadrangular prism, it is preferable that the lead current collecting plate also has a quadrangular shape corresponding to the electrode body or a quadrangular shape with a notch inside.
[0037]
The material of the lead current collector plate is of course electrically conductive, and an electrochemically stable material is desirable for the portion in contact with the electrolytic solution. And it is also necessary to consider the bondability with the lead. In the present embodiment, since the positive electrode-side lead 31 is made of an aluminum-based material as described above, the positive-electrode-side lead current collecting plate 21 to be joined is preferably formed of an aluminum-based material. As described above, since copper is used for the negative-side lead 22, the negative-side lead current collecting plate 22 is preferably formed of a copper-based material or an iron-based material with Ni plating or Cu plating.
[0038]
It is preferable that the lead current collecting plate and the wound end face 30a of the electrode body 30 be as close as possible. It is because dead space is reduced by that amount, and the energy volume density of the completed electrode wound battery is increased.
[0039]
Leads 31 and 32 extending from the winding end surface 30a of the electrode body 30 are joined to lead current collecting plates 21 and 22 disposed substantially parallel to the winding end surface 30a of the electrode body 30 (FIGS. 1 and 2). ). Joining between the lead and the lead current collector plate is performed by ultrasonic joining, welding such as resistance welding and laser welding, brazing, adhesion with a conductive adhesive, or the like. Among these, if the bonding of the lead and the lead current collector plate is performed by ultrasonic bonding, there is little adverse effect such as heat on the electrode body, the lead, and the lead current collecting plate at the time of bonding, It is preferable because sufficient adhesive strength can be secured.
[0040]
An example of the bonding method between the lead and the lead current collector will be described below. When the lead is joined to the surface on the electrode body side of the lead current collector as in this embodiment, the lead can be joined to the lead current collector relatively easily.
[0041]
First, the lead 31 is focused near the winding center of the electrode body 30, and then the focused lead 31 is bent radially outward from the center of winding of the focused electrode body 30, so that the lead 31 is bent to the electrode body 30. After providing the parallel part parallel to the winding end face 30a, the lead current collecting plate 21 is placed in parallel with the parallel part of the lead 31, and then the parallel part of the lead 31 and the lead current collecting plate 21 are joined.
[0042]
Specifically, first, as shown in FIG. 5, a lead focusing jig 70 is installed at the winding center of the electrode body 30 (FIG. 5a). The leads 31 and 32 are bundled around the lead focusing jig 70 by the lead joining anvil 80 (FIG. 5b).
[0043]
As shown in FIG. 6, the lead bonding anvil 80 has several plate-like bodies each having a hole having a size that is the diameter of the lead converging jig 70 plus the thickness of the leads 31 and 32. It has a divided shape. These lead bonding anvils 80 are inserted so as to press the lead 31 from the periphery of the wound end surface 30 a of the electrode body 30 toward the lead focusing jig 70, and the lead 31 is inserted into the lead focusing jig 70. Focus along.
[0044]
The lead bonding anvil 80 is preferably as thin as possible. However, since the lead 31 and the lead current collecting plate 21 are ultrasonically bonded to the lead bonding anvil 80 later as a cradle, the lead bonding anvil 80 has a certain degree of strength. Those are preferred. Note that the lengths of the leads 31 and 32 can be increased as the positions thereof are on the outer periphery so that the heights of the leads 31 and 32 are aligned when the leads are focused around the lead focusing jig 70 (FIG. 5c). ). By aligning the heights of the leads when converged, there is an advantage that the variation in position when the leads are joined to the lead current collector plate is reduced, the joint strength is excellent, and the joints can be favorably joined.
[0045]
After converging the leads, the lead converging jig 70 is removed from the electrode body 30, and instead, the lead bending jig 71 is positioned along the winding center axis of the electrode body 30 at the position where the lead converging jig 70 is located. It is pushed in (Fig. 7a, b). The lead bending jig 71 has a diameter larger than that of the lead converging jig 70, and the side to be pushed into the electrode body 30 is smoothly narrowed. The leads 31 and 32 are bent in the radial direction from the center of the electrode body by the lead bending jig 71. When the lead is bent to some extent, the lead bending jig 71 is removed, and the lead 31 is removed by some method, for example, the current collector plate 21 in this embodiment, so that the lead comes into close contact with the lead bonding anvil 80 as shown in FIG. The parallel part of the lead 31 is formed by pressing. Thereafter, as shown in FIG. 9, the lead horn anvil 80 is used as a pedestal, and the ultrasonic horn 90 is pressed and moved along the surface on the opposite side of the electrode body of the lead current collector plate, thereby paralleling the leads 31. And the lead current collecting plate 21 are ultrasonically bonded.
[0046]
In addition, ultrasonic bonding is not limited to the case where an ultrasonic horn is brought into contact with the surface of the lead current collector plate from the surface opposite to the electrode body of the lead current collector plate to join the lead and the lead current collector plate. An ultrasonic horn may be brought into contact with the lead surface from the surface on the electrode body side and bonded. In this case, the length of the lead is increased so that there is enough space for the ultrasonic horn to enter between the lead current collector plate and the wound end surface of the electrode body, and after ultrasonic bonding, the lead current collector The plate is brought close to the wound end face of the electrode body. In this way, when the ultrasonic horn is brought into contact with the surface of the lead and the lead and the lead current collecting plate are joined, the joining becomes stronger. This is because when a thin member (lead) and a thick member (lead current collector plate) are joined by ultrasonic joining, the ultrasonic horn can be brought into contact with the thin member more firmly.
[0047]
In the electrode winding type battery according to the present embodiment, the lead current collecting plate and the external terminal are joined by inserting the external terminals 41 and 42 into the holes in the center of the lead current collecting plates 21 and 22 in advance, or by connecting the external terminals to the lead terminals. After being fitted into or in contact with the hole of the current collector plate, it can be joined by welding such as laser welding or resistance welding or brazing. Further, a part protruding outside the case may be formed on a part of the lead current collector plate by a press or the like, and the part may be used as an external terminal. That is, the external terminal is not particularly limited as long as it has a known shape and configuration. In FIGS. 8 and 9, external terminals are not joined to the lead current collector for convenience.
[0048]
The case 10 of the electrode wound battery according to this embodiment includes case lids 11 and 12 and a case body 13. In this embodiment, the shape of the case 10 is cylindrical to match the electrode body, and the size thereof is such that the electrode body 30 can be inserted and there is no extra space. In this embodiment, the case lids 11 and 12 have a disk shape having holes through which external terminals on the positive electrode side and the negative electrode side can be inserted, respectively, and the shape of the case body 13 is a cylindrical tube shape.
[0049]
The material of the case is not particularly limited, but both the case lid and the case main body are in contact with the electrolyte solution, and the portion that is in contact with the electrolyte solution is chemically stable. It is necessary to have sufficient strength in the usage form. For example, stainless steel etc. can be used like the electrode winding type battery of this embodiment.
[0050]
The case lids 11 and 12, the positive external terminal 41 and the negative external terminal 42 are electrically insulated and sealed by gaskets 51 and 52, respectively. The method for fixing the external terminal to the case is not particularly limited, but in the present embodiment, it is performed with screws or the like. Further, the case lids 11 and 12 of the electrode wound battery of the present embodiment are fixed to the case main body 13 by welding, but this fixing method is not particularly limited, and caulking, welding, adhesion, etc. Any method that can ensure the hermeticity of the battery case may be used.
[0051]
Note that before the battery is completely sealed, an electrolytic solution is injected into the case 10 to impregnate the electrode body. In the case of a lithium ion secondary battery, LiBF is added to an organic solvent such as ethylene carbonate or diethyl carbonate._Four, LiPF₆A nonaqueous electrolytic solution in which a lithium salt such as an electrolyte is dissolved is used. In addition, although not shown, in the case of a lithium ion secondary battery, a part of the battery case (generally having a flat surface as a case lid) in consideration of an abnormal increase in internal pressure due to gas generation in the case of overcharging, etc. It is a common aspect to provide a safety valve for venting gas, and it is preferable to provide these safety valves also in the present battery.
<Embodiments according to the present invention>
less than,According to the present inventionEmbodiments will be described.
[0052]
BookInvention embodimentIn this embodiment, the leads 31 and 32 are joined to the surfaces of the lead current collector plates 21 and 22 on the electrode body side. However, in the present embodiment, the leads 31 and 32 are connected to the lead current collector plates. The lead current collector plates 21 and 22 are joined to the opposite surface of the electrode body.
[0053]
Figure 10Invention embodimentVarious joining methods for the lead current collecting plates 21 and 22 of the leads 31 and 32 of the electrode winding type battery of FIG.
[0054]
Mentioned abovereferenceIn the embodiment, the leads 31 and 32 and the lead current collecting plates 21 and 22 are joined by bending the leads 31 and 32 radially from the winding center of the winding end surface 30a of the electrode body 30, and the lead current collecting plates 21 and 22. This is a method (a) of joining to the surface of the electrode body.
[0055]
When joining the lead to the electrode body side surface of the lead current collector in this way, an ultrasonic horn or the like is brought into contact with the surface of the lead between the lead current collector plate and the wound end surface of the electrode body to If the gap between the lead current collector plate and the winding end surface of the electrode body is narrow when the lead or lead current collector plate needs to be machined, the lead joining tool or jig cannot be inserted and joined. I can't.
[0056]
Therefore, in such a case, in order to join the lead and the lead current collector, it is necessary to lengthen the lead in advance to ensure a gap. However, when the gap between the lead current collector plate and the wound end surface of the electrode body is reduced later, the lead is not smoothly folded, and the gap between the lead current collector plate and the wound end surface of the electrode body cannot be easily reduced. There is a fear.
[0057]
In such a case, the bonding process is somewhat complicated as compared with the case of bonding the lead to the electrode body side surface of the lead current collector plate by bonding the lead to the opposite surface of the electrode body of the lead current collector plate. However, the above-described limitation in lead processing is eliminated. For example, when the lead and the current collector plate are joined by ultrasonic bonding, the adhesive strength is required, and even if an ultrasonic horn is brought into contact with the lead current collector plate, the lead cannot be joined well. It is necessary to directly contact the ultrasonic horn with the lead.
[0058]
BookInvention embodimentThen,After the leads 31 and 32 are focused on the winding center of the winding end surface 30a of the electrode body 30 and the leads 31 and 32 are passed through the holes in the center of the lead current collecting plates 21 and 22, the leads 31 and 32 are connected to the electrode body. There is a method (b) in which the lead current collecting plates 21 and 22 are bent outward from the winding center 30 and joined to the opposite surfaces of the electrode bodies of the lead current collecting plates 21 and 22. In this method, the lead 31 and the lead current collecting plate are joined by converging the lead to the vicinity of the winding center of the electrode body, passing the lead through the hole in the center of the annular lead current collecting plate 21, and then focusing. The lead 31 is bent radially outward from the winding center of the electrode body 30, the lead 31 is parallel to the lead current collector plate 21, and the lead 31 is joined to the lead current collector plate 21.
[0059]
(Reference embodiment 2)
And bookReference Embodiment 2 Contributing to Understanding of the InventionThe lead 31 is focused on the winding center of the winding end surface 30a of the electrode body 30, the lead 31 is once bent outward from the winding center, the lead current collecting plate 21 is disposed, and the lead 31 is led. The lead 31 is bent toward the winding center of the winding end surface 30a of the electrode body 30 on the surface opposite to the electrode body of the lead current collecting plate 21 so as to wind the outer peripheral portion of the current collecting plate 21. There is a method (c) for joining to the opposite surface of the electrode body 21. In this method, the joining of the lead 31 and the lead current collecting plate 21 is not limited to the surface on the opposite side of the electrode body of the lead current collecting plate 21, and the surface on the electrode body side of the lead current collecting plate 21 may be joined. . In this method, the lead 31 and the lead current collecting plate 21 are joined by converging the lead 31 near the winding center of the electrode body 30, and then the focused lead 31 is focused on the winding center of the electrode body 30. The lead 31 is parallel to the winding end face 30a, the lead current collecting plate 21 is installed in parallel to the lead 31, and the lead 31 is wound around the outer periphery of the lead current collecting plate 21. The electrode body 30 is bent toward the center of winding, and then the lead 31 and the lead current collecting plate 21 are joined on the surface of the lead current collecting plate 21 opposite to the electrode body.
<Deformation mode1>
FIG. 11 shows this variation.1Sectional drawing of this electrode winding type battery is shown.
[0060]
This variation1The electrode winding type battery case 10 includes case lids 11 and 12 and a case body 13. In the present embodiment, the case lids 11 and 12 also serve as positive terminals and negative terminals, respectively. The case lids 11 and 12 are electrically connected to the corresponding lead current collecting plates 21 and 22, respectively.
[0061]
When the case lid is provided with the function of the external terminal in this way, the weight and volume of the case lid are hardly increased, and an external terminal as a separate part is not necessary. Therefore, the battery weight and volume can be reduced by an amount corresponding to the weight and volume of the external terminal.
[0062]
Alternatively, one of the case lids 11 and 12 may be integrated with the case main body 13 from the beginning without being a separate part, and a bottomed cylindrical shape may be formed, and a lead current collector plate may be joined to the bottom portion. And not only the form which uses a case cover as an external terminal of the electrode of both a positive electrode and a negative electrode but the case cover of only one of both electrodes can also be used as an external terminal. When only one is used, the external terminals of the other electrodes may be those of the above-described embodiment. Furthermore, if the case lid further has the function of a lead current collecting plate, the weight can be further reduced.
[0063]
The case lids 11 and 12 and the lead current collecting plates 21 and 22 can be joined by a known method such as laser welding or resistance welding or brazing.
[0064]
Since the case lids 11 and 12 further have the function of external terminals, the material of the case lids 11 and 12 is an electrochemically stable substance in the portion that contacts the electrolyte, such as a lithium ion secondary battery. It is preferable to use an aluminum-based material, a copper-based material on the negative electrode side, or an iron-based material subjected to Ni plating or Cu plating. Since it is necessary to insulate and seal between the case lids 11 and 12 which are external terminals of the positive electrode and the negative electrode, for example, the case body 13 is made of an insulating material such as a polymer material or the case body 13 is made of an insulating material. In order to maintain the insulating state of the case lids 11, 12, it is preferable to seal the case lids 11, 12 in an insulating state with a sealing material or the like (for example, caulking through a sealing material made of an insulating material).
[0065]
Also,Join the lead to the opposite side of the electrode body of the lead current collectorNiThe lead current collecting plates are preferably lead current collecting plates 21 and 22 as shown in FIG. The lead current collector plate is provided with thin portions 21a and 22a in which the thickness of the portion of the lead current collector plate where the leads are joined is reduced by a thickness corresponding to the thickness of the leads 31 and 32 to be joined. (Figure 12a). By providing the thin portions 21a and 22a, the contact area between the lead current collector plates 21 and 22 and the case lids 11 and 12 is increased, and the lead current collector plates 21 and 22 and the case lids 11 and 12 can be easily joined. Moreover, it becomes easy to ensure the strength of joining, and battery internal resistance resulting from this joining surface can be reduced by increasing the joining area.
<referenceDeformation2>
Figure 13 shows the bookShown as a reference to help understand the inventionDeformation2Sectional drawing of this electrode winding type battery is shown.
[0066]
BookreferenceDeformation2In the electrode winding type battery, the lead current collector plate has a function of a safety valve. In other words, the lead current collecting plate 21a is connected to a pipe-like member serving as an external terminal, and the battery inner side of this pipe is sealed with the sealing member 61. The sealing member is, for example, a thin film and is a weak body portion, and bursts and releases internal gas when the internal pressure of the battery increases.
[0067]
By using this lead current collector plate, it becomes possible to give the lead current collector plate the function of a safety valve with almost no increase in weight and volume without using special parts, and the energy weight and volume density of the battery increase. In addition, a highly safe battery can be provided.
[0068]
The lead current collecting plate 21a is composed of two parts: a part for joining the leads and a part protruding from the case lid to the outside and having a role as an external terminal. The part having a role as the external terminal is preferably used for fixing to the case lid by forming a male screw on the outer periphery thereof. The lead current collecting plate 21a may be integrally formed from a plate-like body by pressing, cutting, or the like, or may be divided into two or more parts, and may be combined and integrated later.
[0069]
The lead current collecting plate 21a is fitted into the hole of the case lid 11 after joining the leads, and then fixed to the case lid with a bolt or the like. The insulation between the lead current collecting plate 21a and the case lid is secured by holding the gasket 51 or the like.
[0070]
【The invention's effect】
The electrode wound battery of the present embodiment completed as described above is large in the inside of the battery, which is required in the conventional electrode wound battery that collects current so that current collecting leads are bundled with current collecting parts. Dead space has been eliminated. From this, the electrode wound battery of this embodiment is. The battery has a high energy volume density. In addition, since the internal dead space is small, the amount of the electrolyte to be injected can be reduced, and in this respect also, the battery is inexpensive.
[Brief description of the drawings]
[Figure 1]referenceIt is a perspective view of the electrode winding type battery of an embodiment.
[Figure 2]referenceIt is sectional drawing of the electrode winding type battery of embodiment.
[Fig. 3]referenceIt is a perspective view of the electrode body of the electrode winding type battery of an embodiment.
[Fig. 4]referenceIt is an expanded view of the electrode body of the electrode winding type battery of embodiment.
[Figure 5]referenceIt is the figure which showed the lead condensing process in an example of the joining system of the lead | read | reed and lead current collecting plate of the electrode winding type battery of embodiment.
[Fig. 6]referenceIt is an external view of the anvil for lead joining of embodiment.
[Fig. 7]referenceIt is the figure which showed the lead bending process in an example of the joining system of the lead | read | reed and lead current collecting plate of the electrode winding type battery of embodiment.
[Fig. 8]referenceIt is the figure which showed the joining process to the lead current collecting plate of the lead in an example of the joining method of the lead of the electrode winding type battery of embodiment, and a lead current collecting plate.
FIG. 9referenceIt is the figure which showed one form of the method of ultrasonic bonding of the lead | read | reed of an electrode winding type battery of embodiment, and a lead current collecting plate.
FIG. 10Embodiment of the present inventionIt is a figure which shows the various joining systems of the lead | read | reed and lead current collecting plate of an electrode winding type battery of this.
FIG. 11 shows a modified embodiment.1It is sectional drawing of an electrode winding type battery.
FIG. 12 shows a modified embodiment.1FIG. 5 is a cross-sectional view of a lead current collector plate having a thin wall portion of the electrode wound battery and a lead current collector plate in which a lead and a case lid are joined.
FIG. 13referenceDeformation2It is sectional drawing of an electrode winding type battery.
FIG. 14 is a diagram showing a conventional technique.
FIG. 15 is a diagram showing a conventional technique.

Claims (1)

An electrode body formed by laminating and winding a belt-like positive electrode and a negative electrode;
A plurality of strip-shaped current collecting leads formed at one end in the width direction of at least one of the positive electrode and the negative electrode;
An electrode winding type battery comprising:
Having at least one lead current collector plate disposed substantially parallel to at least one winding end surface on which the lead of the electrode body is formed and having a hole formed therein ;
The leads are bent in the radial direction of the electrode body so as to be focused at the winding center and pass through the holes of the lead current collector plate , and each lead is partially parallel to the surface of the lead current collector plate. An electrode winding type characterized by having parallel portions bent radially outwardly and at least a part of the parallel portions being bonded to the surface of the lead current collector plate opposite to the electrode body battery.

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