JP2003086165A - Cylindrical battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical battery with characteristics will not decreasing even when it is vibrated, and in which a plurality of current-collecting tabs 3 are drawn out of the positive and negative electrodes of a robed electrode body 2 contained in a battery can 1, so that electric power generated by the electrode body 2 can be taken out from a pair of electrode terminal parts via the plurality of current-collecting tabs 3. SOLUTION: In the cylindrical battery, a shaft member 4 is disposed at the center of the rolled electrode body 2, with both ends 41 and 41 of the shaft member 4 protruding from the electrode body 2. Tab holding plates 7 and 7 made of insulating material are attached to both ends 41 and 41 in a manner precluding relative rotation. A plurality of through holes 71 enabling one current- collecting tab 3 to pass therethrough are cut in each of the tab holding plates 7 and 7. Each current-collecting tab 3 is passed through different through holes 71 and connected to electrode terminal mechanisms 5 and 6 at its end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical battery in which an electrode body serving as a power generating element is housed in a battery can and electric power generated by the electrode body can be taken out to the outside.

[0002]

2. Description of the Related Art In recent years, a cylindrical battery having a large energy density has been used as a power source for electric vehicles and the like.
The cylindrical battery is a cylindrical battery can in which lids (12) and (12) are welded and fixed to both ends of a cylindrical body (11), for example, as shown in FIG.
The winding electrode body (9) is housed inside (1). A pair of positive and negative electrode terminal mechanisms (8
0) (81) is attached, the winding electrode body (9) and each electrode terminal mechanism (80) (81) are connected to each other through a plurality of current collecting tabs (3), It is possible to take out the electric power generated by the electrode body (9) from the pair of electrode terminal mechanisms (80) (81) to the outside. Winding electrode body in battery can (1)
(9) is immersed in an electrolytic solution prepared by dissolving an electrolyte in a solvent. In addition, each lid (12) has a pressure opening / closing type gas discharge valve (8
3) is installed.

The winding electrode body (9) is, as shown in FIG.
A strip-shaped separator (92) is interposed between a strip-shaped positive electrode (91) and a strip-shaped negative electrode (93), and these are spirally wound. The positive electrode (91) is a positive electrode active material (9
The negative electrode (93) is formed by applying 4), and the negative electrode active material (95) containing a carbon material is applied on both surfaces of a strip-shaped core made of copper foil. Further, the positive electrode (91) is formed with a non-coated portion (96) to which the positive electrode active material (94) is not applied.
The base ends of the plurality of current collecting tabs (3) are welded to (96). Similarly, the negative electrode (93) is formed with a non-coated portion (97) on which the negative electrode active material (95) is not applied, and the non-coated portion (97) is provided with a plurality of current collecting tabs (3). The base end is welded.

[0004]

By the way, in a battery for an electric vehicle, it is necessary to suppress deterioration of the battery characteristics due to vibrations when mounted on a vehicle. However, in the conventional cylindrical battery as shown in FIG. 4, the current collecting tab (3) vibrates due to the vibration from the outside. A force acts in the direction of pulling (3) out of the winding electrode body (9). Further, when the vibration of the current collecting tab (3) is large, the vibration may cause the current collecting tabs (3) to interfere with each other and exert a force on each other. The pulling force will act on the base end of the. The base end portion of the current collecting tab (3) may be separated from the electrode of the winding electrode body (9) by the pulling force, and the base end portion of the current collecting tab (3) may be separated from the winding electrode body (9). When it is peeled off from the electrode, there is a problem that the cross-sectional area of the current path between the electrode and the electrode terminal mechanism becomes small, the internal resistance of the battery increases, and the battery characteristics deteriorate.

An object of the present invention is to provide a tubular battery whose characteristics do not deteriorate even when it is subjected to vibration.

[0006]

In the cylindrical battery according to the present invention, a plurality of current collecting tabs are respectively drawn from the positive electrode and the negative electrode of the winding electrode body housed inside the battery can. Electric power generated by the winding electrode body can be taken out to the outside from the pair of electrode terminal portions via the plurality of current collecting tabs. A shaft member is provided at the winding center of the winding electrode body, and at least one end of the shaft member projects from the winding electrode body, and a tab holding plate made of an insulating material is relatively opposed to the end portion. It is attached so that it cannot rotate. The tab holding plate is provided with a plurality of through holes through which one current collecting tab can penetrate, and each current collecting tab penetrates a different through hole, and its tip portion is one electrode terminal portion. Are linked to.

In the above cylindrical battery of the present invention, each current collecting tab is restrained by the inner wall of the through hole formed in the tab holding plate, so that when the battery is vibrated,
The current collecting tab does not vibrate greatly. Therefore, a large extraction force does not act on the base end portion of the current collecting tab, and the base end portion of the current collecting tab does not separate from the electrode of the winding electrode body.

In a specific configuration of the present invention, the number of through holes formed in the tab holding plate is larger than the number of current collecting tabs having the same polarity. According to this specific configuration, in the step of inserting the tip of the current collecting tab into the through hole formed in the tab holding plate, the tip of the current collecting tab can be easily inserted from among the plurality of through holes. The holes can be arbitrarily selected. This facilitates the work of passing the current collecting tab through the through hole.

In another specific configuration, at least one liquid hole is formed in the tab holding plate. According to the specific configuration, in the step of injecting the electrolytic solution into the battery can, the electrolytic solution passes through the liquid hole and flows into the accommodation space of the winding electrode body. Therefore, even if the tab holding plate has the same outer diameter as the inner diameter of the cylindrical body, the electrolytic solution is not blocked by the tab holding plate. As a result, the electrolytic solution sufficiently penetrates into the winding electrode body in the battery can.

In yet another specific configuration, the shaft member is formed of one material selected from fluororesin, polyethylene, polypropylene, and ceramic, and the tab holding plate is made of fluororesin or polyethylene. ,
1 selected from polypropylene and ceramic
It is formed using two materials. According to this specific configuration, since the fluororesin, polyethylene, polypropylene, and ceramic are insulating materials, the shaft member and the tab holding plate do not short-circuit between the positive and negative electrodes.

In still another specific configuration, the one electrode terminal portion includes a terminal member that penetrates the lid and is attached to the terminal member, and a pinching member that is screwed to the base end portion of the terminal member. The pinching member engages with the end of the shaft member in a non-rotatable manner, and the tips of the plurality of current collecting tabs are pinched by the pinching member and the terminal member. In the specific structure, since the pinching member engages with the end of the shaft member in a non-rotatable manner, the pinching member and the terminal member are used to fix the tips of the plurality of current collecting tabs. In the pinching step, the pinching member does not rotate together with the terminal member in the process of screwing the base end portion of the terminal member into the pinching member. Therefore, when screwing the base end portion of the terminal member into the pinching member, it is not necessary to directly hold the pinching member.

[0012]

According to the cylindrical battery of the present invention, the base end portion of the current collecting tab does not separate from the electrode of the winding electrode body even if it receives vibration from the outside, so that the electrode and the electrode terminal mechanism are provided. The cross-sectional area of the current path between the two does not decrease to increase the internal resistance of the battery, which prevents the deterioration of the battery characteristics.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a lithium secondary battery will be specifically described below with reference to the drawings. As shown in FIG. 1, the lithium secondary battery of the present embodiment is
A winding electrode body (2) is housed inside a cylindrical battery can (1) in which lids (12) and (12) are fixed by welding to both ends of a cylinder (11). .

A positive electrode terminal mechanism (5) is attached to one lid body (12), and a plurality of leads (3) extending from the positive electrode of the winding electrode body (2) are attached to the positive electrode terminal mechanism (5). It is connected. A negative electrode terminal mechanism (6) is attached to the other lid (12), and a plurality of leads (3) extending from the negative electrode of the winding electrode body (2) are connected to the negative electrode terminal mechanism (6). There is.
This makes it possible to take out the electric power generated by the winding electrode body (2) from the pair of electrode terminal mechanisms (5) and (6) to the outside. A hollow shaft member (4) made of fluororesin is provided at the winding center of the winding electrode body (2),
From both ends of the winding electrode body (2), the end (4
1) (41) is protruding. Further, both ends (41) of the shaft member (4)
Tab holding plates (7) and (7) are attached to (41).
A pressure opening / closing type gas discharge valve (15) (15) is attached to each lid (12).

The winding electrode body (2) is, as shown in FIG.
A strip-shaped separator (22) is interposed between a strip-shaped positive electrode (21) and a strip-shaped negative electrode (23), and these are spirally wound around the shaft member (4). The positive electrode (21) is constituted by applying a positive electrode active material (24) made of a lithium composite oxide on both surfaces of a strip-shaped core made of aluminum foil, and a negative electrode (23).
Is formed by applying a negative electrode active material (25) containing a carbon material on both surfaces of a strip-shaped core body made of copper foil. Further, the positive electrode (21) is formed with a non-coated portion (26) on which the positive electrode active material (24) is not applied, and the non-coated portion (26) is provided with a base end of each current collecting tab (3). The parts are welded. Similarly, for the negative electrode (23), the negative electrode active material (2
The non-coated part (27) which is not coated with 5) is formed, and the base end of each current collecting tab (3) is welded to the non-coated part (27). An outer peripheral surface and an inner peripheral surface of each end portion (41) of the shaft member (4) are each formed as a hexagonal prism surface.

The tab holding plate (7) shown in FIG. 3 is made of a polyethylene disc and has an outer diameter slightly smaller than the inner diameter of the tubular body of the battery can. The tab holding plate (7) has a central hole (73) having a hexagonal cross section, a plurality of through holes (71) larger than the number of current collecting tabs (3) of each pole, and a plurality of liquid holes (72). And have been opened. The cross-sectional shape of each through hole (71) is an arc shape that is concentric with the center of the tab holding plate (7), and has a size that allows one current collecting tab to penetrate therethrough. As shown in FIG. 1, the plurality of current collecting tabs (3) of the positive electrode pass through the through holes (71) of the tab holding plate (7) respectively, and the tip end of each current collecting tab (3) is It is connected to the positive electrode terminal mechanism (5). Negative collector tab (3)
Similarly to the positive electrode current collecting tab (3), the negative electrode terminal mechanism (6)
It is connected to the. A central hole having a hexagonal cross section of the tab holding plates (7) and (7) is fitted into the ends (41) and (41) of the shaft member (4). As a result, the outer peripheral surface of the hexagonal cylindrical surface of the end portions (41) (41) of the shaft member (4) and the inner wall of the central hole of the tab holding plate (7) (7) having a hexagonal cross section are engaged, The member (4) and the tab holding plates (7, 7) are connected to each other so that they cannot rotate relative to each other.

The positive electrode terminal mechanism (5) is a cover (1) for the battery can (1).
The positive electrode terminal member (50) is formed of a screw member penetrating through 2) and the pinching member (56) screwed to the positive electrode terminal member (50). A flange portion (52) is formed at the base end of the positive electrode terminal member (50), and a screw hole (51) is formed on the surface of the flange portion (52) in the axial direction of the positive electrode terminal member (50). It is recessed. An insulating member (53) made of resin is attached to the through hole of the lid body (12) to maintain electrical insulation and sealing between the lid body (12) and the positive electrode terminal member (50). . Further, an O-ring (44) is attached to the lid body (12) to ensure the sealing property between the lid body (12) and the insulating member (53). Also, the insulating member (53) has O
The ring (45) is attached, and the insulating member (53) and the positive terminal member (5
The sealability between the collar portion (52) of (0) is ensured.
Attach the washer from the outside of the battery can (1) to the positive electrode terminal member (50).
(54) is fitted and the nut (55) is screwed.
Then, by tightening the nut (55), the positive electrode terminal member (50)
By sealing the insulating member (53) by the collar portion (52) and the washer (54), the sealing performance is improved.

The pressing member (56) includes a flat plate portion (57) and the flat plate portion (57).
The screw shaft (58) is provided on the front surface of the (57), and the insertion shaft (59) is provided on the back surface of the flat plate portion (57). The screw shaft (58) is screwed into the screw hole (51) of the positive electrode terminal member (50). As a result, the tips of the plurality of current collecting tabs (3) are sandwiched between the back surface of the flange portion (52) of the positive electrode terminal member (50) and the pinching member.
It is sandwiched between the flat plate portion (57) and the surface of (56). The insertion shaft (59) protruding from the back surface of the flat plate portion (57) is the shaft member.
It is inserted into the hollow part of the end (41) of (4). As a result, the outer peripheral surface of the hexagonal cylindrical surface of the insertion shaft of the flat plate portion (57) and the inner peripheral surface of the hexagonal cylindrical surface of the end portion (41) of the shaft member (4) are engaged,
The pressing member (56) and the shaft member (4) are connected to each other so that they cannot rotate relative to each other. However, the pinching member (57) is movable in the axial direction of the shaft member (4). This makes it possible to adjust the position of each member when assembling the battery. The negative electrode terminal mechanism (6) is also configured similarly to the positive electrode terminal mechanism (5).

Next, a method for manufacturing the above lithium secondary battery will be described.
explain about.Fabrication of positive electrode First, lithium cobalt oxide (LiCoO_Two) Powder and carbon
Conductive agent consisting of powder and polyvinylidene fluoride (PVd
90% to 5% by weight of a binder consisting of F)
And mixed to prepare a positive electrode mixture. Then this positive
Slurry by adding N-methyl-2-pyrrolidone to the electrode mixture
And apply it to aluminum foil,
After vacuum drying for a period of time, a positive electrode (21) as shown in Fig. 2 is prepared.
To make. In addition, the non-coated part (26) has a plurality of aluminum
Weld the current collecting tabs (3) made of steel.Fabrication of negative electrode First, natural graphite powder and polyvinylidene fluoride (PV
90% by weight ratio with a binder consisting of dF)
To prepare a negative electrode mixture. Next, this negative electrode mixture
N-methyl-2-pyrrolidone was added to
Then, apply this to copper foil and vacuum dry at 150 ° C for 2 hours.
Then, a negative electrode (23) as shown in FIG. 2 is produced. Also, non
The coating part (27) has a plurality of nickel current collecting tabs (3).
Weld.

[0020]Fabrication of winding electrode body The positive electrode (21) obtained by the step of producing the positive electrode,
Between the negative electrode (23) obtained by the manufacturing process of the negative electrode,
A separator (22) consisting of a polyethylene microporous thin film
These are put on top of each other and sandwiched. However, the positive electrode (21)
The negative electrode (23) and the negative electrode (23)
Position (3) in the opposite orientation. Positive superimposed
The pole (21), the separator (22), the negative electrode (23), the shaft member (4)
Winding electrode body in a spiral shape as a winding shaft
(2) is prepared.Preparation of electrolyte Volume of ethylene carbonate and diethyl carbonate
A mixed solvent is prepared by mixing at a ratio of 1: 1. this
1 mol / liter of lithium hexafluorophosphate in mixed solvent
To prepare an electrolytic solution.

[0021]Fabrication of tab holding plate As shown in Fig. 3, a polyethylene disc with a hexagonal cross section
Central hole (73), multiple through holes (71), multiple liquid holes (72)
The tab holding plate (7) is prepared by opening and.Battery assembly First, as shown in FIG. 1, from the positive electrode of the winding electrode body (2),
Each of the extending current collecting tabs (3) has a different through hole (71) at the tip thereof.
And then project it through the through hole (71). Where multiple
The number of through-holes (71) in each is the same as the number of collector tabs (3) on each pole.
Through holes that allow for easy insertion of the current collecting tabs (3) because there are more than
(71) can be selected. Then tab retaining plate (7)
The central hole of the shaft member is fitted into the end portion (41) of the shaft member (4). Next
Then, insert the inserting shaft (59) of the pinching member (56) into the end portion (41) of the shaft member (4).
Insert it into the hollow part of. After that, the tip of each current collecting tab (3)
Is placed on the surface of the flat plate part (57) of the pinching member (56), and the positive terminal
Screw the screw hole (51) of the member (50) into the screw shaft (58) of the pinching member (56).
Put together. As a result, the flat plate portion (57) of the pressing member (56)
Between the positive electrode terminal member (50) and the flange portion (52) of the positive electrode terminal member (50).
Hold the tip of the knob (3). Each collector tab (3) of the negative electrode is
In the same manner as the current collecting tabs (3) of the positive electrode described above, the pressing member (6
Hold it between the flat plate part of 6) and the collar part of the negative electrode terminal member (60).
It Then, the winding electrode body (2) is placed inside the cylindrical body (11).
Insert the insulating member (53) into the through hole of one lid (12).
Insert the positive electrode terminal member (50) into the through hole of the insulating member (53).
Then, while fitting the washer (54) to the positive electrode terminal member (50),
Tighten the nut (55). In this way, the positive terminal mechanism
Assemble (5). In addition, the negative terminal mechanism (6)
Assemble in the same manner as structure (5). Then each of the cylinders (11)
Weld and fix each lid (12) to the opening, and insert one lid (12)
Install the gas discharge valve (15) in the
Electrolyte into the battery can (1) from the gas exhaust valve mounting hole of the body (12)
inject. Finally, the gas exhaust valve (1
5) is attached to complete the lithium secondary battery of this embodiment.
It

In the lithium secondary battery of the above embodiment, since each current collecting tab (3) is restrained by the inner wall of the through hole (71) of the tab holding plate (7), the secondary battery vibrates. When receiving, each current collecting tab (3) only vibrates slightly. As a result, the pulling force acting on the base end portion of the current collecting tab (3) is sufficiently smaller than the pulling force when the current collecting tab of the conventional tubular battery vibrates. Further, since the current collecting tabs (3) vibrate slightly, the current collecting tabs (3) do not interfere with each other to exert a force. Therefore, the current collector tab
At the base end of (3), the pull-out force due to the interference between the current collecting tabs (3) does not occur. As a result, there is no risk that the base end of the current collecting tab (3) will be separated from the electrode of the winding electrode body (2).
As a result, the winding electrode body (4) and each pole terminal mechanism (5)
Since the cross-sectional area of the current path between (6) is maintained, the internal resistance of the battery does not increase, and the deterioration of the battery performance is prevented.

The electrolytic solution injected into the battery can (1) is
It passes through a plurality of liquid holes (72) formed in the tab holding plate (7). Therefore, the electrolytic solution penetrates into the winding electrode body (2) without being blocked by the tab holding plate (7).
Furthermore, screw the screw holes (51) (61) of the terminal members (50) (60) of each pole to the screw shafts (58) (68) of the pinching members (56) (66) of each pole,
Collar portions (52) (62) of the terminal members (50) (60) and clamping members (56) of each pole
Multiple collector tabs for each pole between the flat plate part (57) and (67) of (66)
In the step of pinching the tip of (3), the pinching member (56) (6
6) engages with the respective end portions (41) of the shaft member (4) in a relatively non-rotatable manner, so that the screw holes (51) (61) of the terminal members (50) (60) of the respective poles are connected to the respective poles. In the process of screwing the pinching members (56) (66) into the screw shafts (58) (68), the pinching members (56) (66) do not rotate together with the terminal members (50) (60). Therefore, the screw holes (51) (61) of the terminal members (50) (60) of each pole are connected to the screw shafts (58) (68) of the pinching members (56) (66) of each pole.
It is not necessary to hold the clamping members (56) (66) when screwing into. Further, a pinching member that constitutes the electrode terminal mechanism (5) (6)
Insert the insertion shafts (59) and (69) of (56) and (66) into the ends (41) and (41) of the shaft member (4).
The shaft member (4) is restrained from moving in a direction orthogonal to the axial direction by inserting the shaft member (4) into the hollow portion. As a result, the movement of the winding electrode body (2) in the direction orthogonal to the axial direction is also restricted. As a result, vibration of the winding electrode body (2) in a direction orthogonal to the axial direction is suppressed.

The contents and results of the experiment conducted to confirm the effect of the lithium secondary battery according to the present invention will be described below. [Experiment] Inventive battery 1, inventive battery 2, comparative battery 1 and comparative battery 2 described below were produced, and after measuring the internal resistance of each battery, a vibration test was conducted to measure the internal resistance after the vibration test. did. Internal resistance measurement frequency is 1 kHz
And The vibration test is a packaged cargo-vibration test method (JIS
Z 0232). The test conditions were a peak acceleration of ± 0.75 G, a vibration time of 20 minutes, a frequency range of 5 Hz to 50 Hz, and a vibration direction of up and down.

Inventive battery 1 was made in the same manner as in the above embodiment. Inventive battery 2 was manufactured in the same manner as in the above-mentioned embodiment, except that the tab holding plate was made of ceramic and the shaft member was made of polyethylene. Comparative battery 1 was produced in the same manner as in the above example except that the tab holding plate was not attached. The comparative battery 2 has the same structure as the conventional cylindrical battery shown in FIG. Table 1 shows the measurement results of the internal resistance of each battery.

[0026]

[Table 1]

As is clear from the results shown in Table 1, the invention batteries 1 and 2 had the same internal resistance before and after the vibration test. On the other hand, in Comparative Battery 1 and Comparative Battery 2, the internal resistance after the vibration test was larger than that before the vibration test. From these results, in the tubular battery according to the present invention, the base end portion of the current collecting tab does not separate from the electrode of the winding electrode body even when subjected to vibration, and the winding electrode body and each pole terminal mechanism are It was confirmed that the internal resistance of the battery did not increase because the cross-sectional area of the current path between the two was maintained.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, in the above example, the winding electrode body was produced using the shaft member as the winding shaft,
A winding electrode body is produced using a conventional winding shaft, the winding shaft is extracted from the winding electrode body, and then the shaft member according to the present invention is placed in a space formed in the center of the winding electrode body. It is also possible to adopt the step of inserting.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lithium secondary battery according to the present invention.

FIG. 2 is a partially exploded perspective view of a winding electrode body used in the secondary battery.

FIG. 3 is a plan view showing a tab holding plate used for the secondary battery.

FIG. 4 is a cross-sectional view of a conventional lithium secondary battery.

FIG. 5 is a partially exploded perspective view of a winding electrode body used in the secondary battery.

[Explanation of symbols]

(1) Battery can (2) Winding electrode body (3) Power collection tab (4) Shaft member (5) Positive electrode terminal mechanism (50) Positive terminal member (56) Clamping member (6) Negative electrode terminal mechanism (7) Tab holding plate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsuhiro Funabashi             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Toshiyuki Noma             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Ikuro Ikuro             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5H022 AA18 BB03 CC02 CC19 CC22                       EE06 KK03

Claims (5)

[Claims] 1. A plurality of current collecting tabs are drawn out from a positive electrode and a negative electrode of a winding electrode body housed inside a battery can, respectively. Electric power generated by the winding electrode body is supplied to the plurality of current collecting tabs. In a tubular battery that can be taken out from a pair of electrode terminal portions via a current collecting tab, a shaft member is provided at the winding center of the winding electrode body, and at least one end of the shaft member is A tab holding plate made of an insulating material is attached to the end of the winding electrode body so as to be relatively non-rotatable, and a plurality of penetrating holes through which one current collecting tab can pass. A cylindrical battery, wherein holes are provided, each current collecting tab penetrates through a different through hole, and a tip portion thereof is connected to one electrode terminal portion. 2. The number of through holes formed in the tab holding plate is larger than the number of current collecting tabs having the same polarity.
The cylindrical battery according to. 3. The tubular battery according to claim 1, wherein at least one liquid hole is formed in the tab holding plate. 4. The shaft member is made of one material selected from fluororesin, polyethylene, polypropylene, and ceramic, and the tab holding plate is made of fluororesin, polyethylene, polypropylene, and ceramic. The cylindrical battery according to any one of claims 1 to 3, which is formed by using one material selected from the inside. 5. The one electrode terminal portion includes a terminal member attached through the lid body, and a pinching member screwed to a base end portion of the terminal member. The member is engaged with an end portion of the shaft member so as not to be rotatable relative to each other, and the tip end portions of the plurality of current collecting tabs are held by the holding member and the terminal member. The cylindrical battery according to any one of the above.