JP3939116B2 - Secondary battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a secondary battery in which an electrode body serving as a secondary battery element is accommodated in a battery can, and electric power generated by the electrode body can be taken out from a pair of electrode terminal portions provided in the battery can. Is.
[0002]
[Prior art]
In recent years, lithium ion secondary batteries with high energy density have attracted attention as power sources for portable electronic devices and electric vehicles. For example, as shown in FIG. 6, a cylindrical lithium ion secondary battery having a relatively large capacity used for an electric vehicle is a cylinder in which lids (12) and (12) are fixed to both ends of a cylinder (11). The take-up electrode body (2) is accommodated in a battery-like battery can (1).
A pair of positive and negative electrode terminal mechanisms (40), (40) is attached to the lids (12), (12), and both electrodes of the winding electrode body (2) and both electrode terminal mechanisms (40), (40) Are connected to each other, and the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (40), (40). Each lid (12) is screwed with a screw cap (14) for closing the screw hole (18) for injecting the electrolyte into the battery can (1), and has a gas discharge hole (17). A gas exhaust valve (13) for closing is attached.
[0003]
As shown in FIG. 7, the take-up electrode body (2) is formed by interposing a strip-shaped separator (22) between the strip-shaped positive electrode (21) and the negative electrode (23), and winding them in a spiral shape. It is configured. The positive electrode (21) is configured by applying a positive electrode active material (24) made of a lithium composite oxide on both surfaces of a band-shaped core (25) made of an aluminum foil, and the negative electrode (23) is made of a band-shaped core made of a copper foil. The negative electrode active material (26) containing a carbon material is applied to both surfaces of the body (27). The separator (22) is impregnated with a non-aqueous electrolyte.
The positive electrode (21) is formed with a non-coated portion where the positive electrode active material (24) is not applied, and the base end portion of the plurality of current collecting tabs (3) is joined to the non-coated portion. ing. Similarly, the negative electrode (23) is formed with a non-coated portion to which the negative electrode active material (26) is not applied, and the base end portion of a plurality of current collecting tabs (3) is joined to the non-coated portion. ing.
[0004]
And as shown in FIG. 6, the front-end | tip part of several current collection tabs (3) with the same polarity is connected to one electrode terminal mechanism (40). In FIG. 6, for convenience, the tip of some of the current collecting tabs is shown connected to the electrode terminal mechanism (40), and for the other current collecting tabs, the tip of the current collecting tab is the electrode terminal mechanism (40). ) Is not shown.
[0005]
The electrode terminal mechanism (40) includes an electrode terminal member (9) attached through the lid (12) of the battery can (1). The electrode terminal member (9) includes the lid (12). A flange portion (91) protruding into the battery can (1) is provided at the proximal end portion of the threaded shaft portion (92) that penetrates, and a prism portion (93) is provided at the distal end portion.
A cylindrical insulating seal member (8) is mounted in the through hole of the lid (12), and a disk-shaped insulating seal member (81) is installed on the surface of the lid (12). Between the opposing surfaces of the cylindrical insulating seal member (8) and the flange portion (91) of the electrode terminal member (9) and between the opposing surfaces of the cylindrical insulating seal member (8) and the lid (12). The O-rings (82) and (83) are interposed to provide electrical insulation and sealing between the lid (12) and the electrode terminal member (9).
The insulating seal members (8) and (81) are made of polypropylene.
[0006]
A washer (71) and a spring washer (72) are fitted to the screw shaft portion (92) of the electrode terminal member (9) from the outside of the lid (12), and a nut (7) is screwed together. The nut (7) is tightened, and the insulating seal members (8) (81) and the O-rings (82) (83) are clamped between the flange portion (91) and the washer (71) of the electrode terminal member (9). This improves the sealing performance.
[0007]
Further, a tab connecting screw member (41) is screwed into the flange portion (91) of the electrode terminal member (9), and is wound between the flange portion (91) and the tab connecting screw member (41). The tip ends of a plurality of current collecting tabs (3) extending from the collecting electrode body (2) are sandwiched.
[0008]
[Problems to be solved by the invention]
However, the conventional cylindrical secondary battery is an assembly process in which the electrode terminal mechanism (40) is assembled to the lid (12) constituting the battery can (1) and then the nut (7) is screwed. In some cases, the electrode terminal member (9) rotates along with the rotation of the nut (7). For this reason, there was a problem that the nut (7) could not be tightened with sufficient strength and the contact resistance increased.
[0009]
According to the step of attaching the electrode terminal mechanism (40) to the lid (12) before fixing the lid (12) to the cylinder (11), the flange (91) of the electrode terminal member (9) is attached to the tool Thus, it is possible to prevent the electrode terminal member (9) from being rotated and to prevent the current collecting tab (3) from being damaged. However, in a cylindrical secondary battery used for an electric vehicle, for example, the nut (7) may be loosened due to the influence of vibration. In this case, it is necessary to retighten the nut (7). There arises a problem that the member (9) is accompanied.
[0010]
Therefore, a secondary battery (Japanese Patent Laid-Open No. 9-92238) in which the electrode terminal mechanism and the lid are fixed to each other using a rotation stop pin has been proposed. In order to do this, a new insulating member is required, which increases the number of parts. In addition, since it is necessary to fix the rotation stop pin and the lid to each other by welding, there is a problem that the number of manufacturing steps increases and the cost increases.
[0011]
An object of the present invention is to provide a secondary battery that can prevent the electrode terminal member from being accompanied when the electrode terminal mechanism is fixed to the lid, and does not increase the number of parts and the number of manufacturing steps. That is.
[0012]
[Means for solving the problems]
In the secondary battery according to the present invention, an electrode body (2) serving as a secondary battery element is accommodated in the battery can (1), and electric power generated by the electrode body (2) is supplied to a pair of electrode terminal portions. Can be taken out from the outside. Here, at least one of the electrode terminal portions is formed by an electrode terminal mechanism (4) attached to the battery can (1), and the electrode terminal mechanism (4)
Installed through the central hole (19) established in the battery can (1), the flange portion (51) projecting inside the battery can (1), and the screw shaft projecting outside the battery can (1) An electrode terminal member (5) comprising a portion (52);
The battery can (1) and the electrode terminal member (1) are interposed between the inner peripheral surface of the central hole (19) of the battery can (1) and the outer peripheral surface of the screw shaft portion (52) of the electrode terminal member (5). An insulating seal member (6) for electrical insulation and sealing between 5);
Nut (7) screwed into the screw shaft (52) of the electrode terminal member (5) from the outside of the battery can (1)
The insulating seal member ( 6 ) is provided with a central hole (64) through which the screw shaft portion (52) of the electrode terminal member ( 5 ) passes , and around the central hole (64) . The first and second peripheral walls that are not perfect circles , each centering on the central hole (64) , are formed, and the first peripheral wall of the insulating seal member ( 6 ) is not relatively rotatable on the battery can ( 1 ). An engagement recess (16) having a third peripheral wall to be engaged is formed, and the flange portion (51) of the electrode terminal member ( 5 ) cannot be rotated relative to the second peripheral wall of the insulating seal member ( 6 ). A fourth peripheral wall is formed to engage the.
[0013]
In the secondary battery of the present invention, the screw terminal (52) of the electrode terminal member (5) is rotated by rotating the nut (7) with the electrode terminal mechanism (4) assembled to the battery can (1). The insulating seal member (6) is clamped between the flange portion (51) of the electrode terminal member (5) and the nut (7), and the electrode terminal mechanism (4) becomes the battery can (1). The insulating seal member (6) exhibits a sufficient sealing performance.
In the operation of rotating the nut (7), the rotational force of the nut (7) is transmitted to the electrode terminal member (5) and the electrode terminal member (5) receives the rotational force, but the flange of the electrode terminal member (5) The portion (51) is engaged with the insulating seal member (6) so as not to be relatively rotatable, and the insulating seal member (6) is engaged with the battery can (1) so as not to be relatively rotatable. The rotational force acting on 5) is received by the battery can (1).
Therefore, the electrode terminal member (5) is not accompanied.
[0014]
Further, since no special member is required to prevent the electrode terminal member 5 from being accompanied, the number of parts does not increase and the structure is simple.
Furthermore, the insulating seal member (6) can be easily manufactured by integral molding of resin as in the case of the conventional insulating seal member. However, the number of assembling steps is not different from the conventional one and the manufacturing process is simple.
[0015]
In addition, the conventional battery can (1), electrode terminal member (5), and insulation seal member (6) are provided with a structure for preventing accompanying rotation, so the same component structure as before. Thus, the present invention can be realized.
[0017]
More specifically, the insulating seal member (6) has a plate-shaped main body (60) , and one or more corners are formed on the outer peripheral wall of the main body (60) , and the first outer wall is formed by the outer peripheral wall . A peripheral wall is formed.
In the specific configuration, the corner portion formed in the main body (60) of the insulating seal member (6) is sharply engaged with the peripheral wall of the battery can (1), so that the insulating seal member (1) for the battery can (1) ( The relative rotation of 6) is reliably prevented. Further, since the interval between the two peripheral walls of the insulating seal member (6) can be increased, the strength of the insulating seal member (6) is increased, and as a result, the electrode terminal member (6) of the electrode seal member (6) is increased. 5) The accompanying stop force for 5) increases.
[0018]
In a specific configuration, the outer peripheral wall of the flange portion (51) of the electrode terminal member (5) has a shape in which a part of the cylindrical surface is replaced with a flat surface, and the insulating seal member (6) includes the electrode. An engagement recess (62) is formed in which the outer peripheral wall of the flange portion (51) of the terminal member (5) is engaged in a relatively non-rotatable manner, and the second peripheral wall is formed by the inner peripheral wall of the engagement recess (62). Has been.
According to the specific configuration, the flange portion (51) of the electrode terminal member (5) and the engagement recess (62) of the insulating seal member (6) can be easily processed, and the electrode terminal member (5). It is possible to reliably prevent the accompanying electrode terminal member (5) from being fixed.
[0019]
Furthermore, in a specific configuration, the outer peripheral wall of the flange portion (51) of the electrode terminal member (5) has one or more corners , and the insulating seal member (6) includes the electrode terminal member (5). of the outer peripheral wall of the flange portion (51) engaging recess to be engaged in relative rotation (62) is formed, the second wall by the inner wall of the engaging recess (62) is formed.
According to the specific configuration, the corner portion formed in the flange portion (51) of the electrode terminal member (5) is sharply engaged with the engaging recess (62) of the insulating seal member (6), thereby insulating seal. The relative rotation of the electrode terminal member (5) with respect to the member (6) is reliably prevented, and as a result, the accompanying movement of the electrode terminal member (5) when the electrode terminal member (5) is fixed can be reliably prevented. I can do it.
[0020]
【The invention's effect】
According to the secondary battery of the present invention, it is possible to prevent the electrode terminal member from being accompanied when the electrode terminal mechanism is fixed to the lid without increasing the number of parts and the number of manufacturing steps.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention applied to a cylindrical lithium ion secondary battery will be described in detail with reference to the drawings.
As shown in FIG. 1, a cylindrical lithium ion secondary battery according to the present invention is a cylindrical aluminum battery can (1) formed by welding and fixing lids (12) to both openings of a cylindrical body (11). ) Is housed in the winding electrode body (2). The battery can (1) has an outer diameter of 57 mm and a length of 220 mm.
The configuration of the winding electrode body (2) is the same as the conventional configuration shown in FIG.
[0022]
An electrode terminal mechanism (4) is attached to each lid (12) constituting the battery can (1). In addition, each lid (12) is screwed with a screw plug (14) into a screw hole (18) for injecting an electrolyte into the battery can (1) as in the prior art, and a gas discharge hole. A gas discharge valve (13) for closing (17) is attached.
[0023]
Connected to the electrode terminal mechanism (4) are tips of a plurality of current collecting tabs (3) having the same polarity extending from the take-up electrode body (2). In FIG. 1, for the sake of convenience, the tip of some of the current collecting tabs is shown connected to the electrode terminal mechanism (4), and the tip of the other current collecting tabs is connected to the electrode terminal mechanism (4 ) Is not shown.
[0024]
As shown in FIGS. 1 and 2, the electrode terminal mechanism (4) includes an electrode terminal member (5) attached through the central hole (19) of the lid (12). ) Includes a flange portion (51) protruding into the battery can (1) at the base end of the screw shaft portion (52) passing through the central hole (19) of the lid (12), and the battery can A tip portion protruding outward of (1) is provided with a prism portion (53).
A cylindrical insulating seal member (6) is attached to the central hole (19) of the lid (12), and a disc-shaped insulating seal member (61) is formed at the opening edge of the central hole (19). Furthermore, between the opposed surfaces of the cylindrical insulating seal member (6) and the flange portion (51) of the electrode terminal member (5), and between the cylindrical insulating seal member (6) and the lid (12). O-rings (82) and (83) are interposed between the opposing surfaces, and electrical insulation and sealing are performed between the lid (12) and the electrode terminal member (5).
The electrode terminal member (5) of the electrode terminal mechanism (4) on the positive electrode side is made of aluminum, and the electrode terminal member (5) of the electrode terminal mechanism (4) on the negative electrode side is made of nickel. In any electrode terminal mechanism (4), the insulating seal members (6) and (61) are made of polypropylene, and the O-rings (82) and (83) are made of fluororesin.
[0025]
A washer (71) and a spring washer (72) are fitted to the screw shaft portion (52) of the electrode terminal member (5) from the outside of the lid (12), and a nut (7) is screwed together. The nut (7) is tightened, and the insulating seal members (6) (61) and the O-rings (82) (83) are clamped between the flange portion (51) and the washer (71) of the electrode terminal member (5). This improves the sealing performance.
[0026]
Further, a tab connecting screw member (41) is screwed into the flange portion (51) of the electrode terminal member (5), and is wound between the flange portion (51) and the tab connecting screw member (41). The tip ends of a plurality of current collecting tabs (3) extending from the collecting electrode body (2) are sandwiched.
[0027]
In the electrode terminal mechanism (4), as shown in FIG. 3, the insulating seal member (6) protrudes upward at the central part of the square plate body (60) with the cylindrical part (63) having the central hole (64). An oblong engaging recess (62) having an inner peripheral surface in which a part of the cylindrical surface is replaced with a flat surface is formed on the back surface of the square plate-shaped main body (60).
On the other hand, on the back surface of the lid (12), there is a rectangular engagement recess (16) with which the square plate-like body (60) of the insulating seal member (6) can engage with the center hole (19) as the center. Is formed.
The flange portion (51) of the electrode terminal member (5) has an oval shape that can be engaged with an engagement recess (62) formed in the square plate-like body (60) of the insulating seal member (6). It has an outer shape.
[0028]
Therefore, as shown in FIG. 1, after the electrode terminal mechanism (4) is assembled to the lid (12), the nut (7) is rotated and tightened, and the rotational force of the nut (7) is the electrode terminal member (5). However, the flange portion (51) of the electrode terminal member (5) engages with the insulating seal member (6) so as not to rotate relative thereto, and the insulating seal member (6) rotates relative to the lid body (12). Since the engagement is impossible, the rotation of the electrode terminal member (5) is prevented.
Since the rotation of the electrode terminal member (5) accompanying the tightening of the nut (7) is prevented in this way, a sufficient tightening torque can be applied to the nut (7), thereby reducing the contact resistance. I can do it.
[0029]
Further, in the cylindrical lithium ion secondary battery according to the present invention, the lid (12), the insulating seal member (8), and the electrode terminal member provided in the conventional cylindrical lithium ion secondary battery shown in FIG. Instead of (9), a lid (12), an insulating seal member (6) and an electrode terminal member (5) shown in FIGS. 1 to 3 are provided. In the present invention, the lid (12) is rectangular. Are formed in the electrode terminal member (5) with an oblong flange portion (51), and the insulating seal member (6) with a square plate body (60) and an engagement recess portion (62). By doing so, the accompanying rotation of the electrode terminal member (5) is prevented, so that the number of parts and the number of manufacturing steps are not increased.
However, the cylindrical lithium secondary battery according to the present invention can be easily assembled through the same process as the conventional one.
[0030]
The engagement structure of the lid (12), the insulating seal member (6), and the electrode terminal member (5) is not limited to the structure shown in FIG. 3, and for example, the structure shown in FIG. 4 can be adopted. In the engagement structure shown in FIG. 4, the insulating seal member (6) is formed by projecting upward a cylindrical portion (63) having a central hole (64) at the central portion of the square plate-shaped main body (60). A rectangular engagement recess (62) is formed on the back surface of the square plate-like body (60). The flange portion (51) of the electrode terminal member (5) has a square plate shape that can be engaged with an engagement recess (62) formed in the square plate body (60) of the insulating seal member (6). It has an outer shape.
Also with the engagement structure, the effect of preventing rotation of the electrode terminal member (5) can be obtained as in the engagement structure shown in FIG.
[0031]
FIG. 1 shows the present invention battery shown in FIG. 1 and the conventional battery shown in FIG. 6 in order to confirm the effect of preventing the electrode terminal member (5) from being rotated by the electrode terminal mechanism (4) of the present invention. In the battery of the present invention, the nut (7) is tightened using a torque wrench with a torque of 80 Kgf · cm. In the conventional battery shown in FIG. 6, the torque wrench is used until the electrode terminal member (9) starts rotating together. The battery was assembled by tightening the nut (7) using The final tightening torque in the conventional battery was 40 kgf · cm.
[0032]
Then, using the above-described battery of the present invention and the conventional battery, a module battery composed of four unit cells (10) was assembled as shown in FIG. The four unit cells (10) were connected in series by sandwiching a connecting portion of the connecting tool (15) between the spring washer (72) and the nut (7). And the resistance value of the module battery of this invention and the conventional module battery was measured with the alternating current resistance meter of 1 kHz.
As a result, the resistance value of the module battery of the present invention was 9.3 mΩ, whereas the resistance value of the conventional module battery was 15.6 mΩ.
[0033]
In the battery of the present invention, since the electrode terminal member (5) and the lid (12) are engaged with each other so as not to rotate relative to each other, a sufficient tightening torque can be applied, thereby reducing the contact resistance. However, in the conventional battery, a sufficient tightening torque cannot be applied because the electrode terminal member (9) is accompanied, thereby increasing the contact resistance.
[0034]
In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, a sheet-like seal packing can be employed instead of the O-rings (82) and (83).
The engagement structure between the lid (12) and the insulating seal member (6) and the engagement structure between the insulating seal member (6) and the electrode terminal member (5) are rectangular as shown in FIGS. As long as the engagement structure is not limited to an engagement structure using an ellipse or a pair of engagement surfaces that cannot rotate relative to each other, an engagement structure using engagement surfaces having various shapes may be employed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of a cylindrical lithium ion secondary battery according to the present invention.
FIG. 2 is an exploded front view showing a part of the electrode terminal mechanism in a cutaway manner.
FIG. 3 is an exploded perspective view of a lid, an insulating seal member, and an electrode terminal member.
FIG. 4 is an exploded perspective view of a lid, an insulating seal member, and an electrode terminal member in another embodiment.
FIG. 5 is a perspective view of a module battery.
FIG. 6 is a cross-sectional view showing a main part of a conventional cylindrical lithium ion secondary battery.
FIG. 7 is a partially developed perspective view of a wound electrode body.
[Explanation of symbols]
(1) Battery can
(11) Tube
(12) Lid
(16) Engaging recess
(2) Winding electrode body
(3) Current collection tab
(4) Electrode terminal mechanism
(5) Electrode terminal member
(51) Flange
(52) Screw shaft
(6) Insulating seal member
(60) Square plate body
(62) Engaging recess
(7) Nut
(71) Washer
(72) Spring washer
(82) O-ring
(83) O-ring
(41) Screw member for tab connection

Claims (4)

A secondary battery in which an electrode body (2) serving as a secondary battery element is accommodated in the battery can (1) and the electric power generated by the electrode body (2) can be taken out from a pair of electrode terminal portions. At least one of the electrode terminal portions is formed by an electrode terminal mechanism (4) attached to the battery can (1), and the electrode terminal mechanism (4)
Installed through the center hole (19) established in the battery can (1), the flange portion (51) protruding inside the battery can (1) and the screw shaft protruding outside the battery can (1) An electrode terminal member (5) comprising a portion (52);
The battery can (1) and the electrode terminal member (1) are interposed between the inner peripheral surface of the central hole (19) of the battery can (1) and the outer peripheral surface of the screw shaft portion (52) of the electrode terminal member (5). An insulating seal member (6) for electrical insulation and sealing between 5);
Nut (7) screwed into the screw shaft (52) of the electrode terminal member (5) from the outside of the battery can (1)
The insulating seal member ( 6 ) is provided with a central hole (64) through which the screw shaft portion (52) of the electrode terminal member ( 5 ) passes , and around the central hole (64) . The first and second peripheral walls that are not perfect circles , each centered on the central hole (64) , are formed, and the first peripheral wall of the insulating seal member ( 6 ) is not rotatable relative to the battery can ( 1 ). An engagement recess (16) having a third peripheral wall to be engaged is formed, and the flange portion (51) of the electrode terminal member ( 5 ) cannot be rotated relative to the second peripheral wall of the insulating seal member ( 6 ). A secondary battery, wherein a fourth peripheral wall that engages with the battery is formed . Insulating sealing member (6) comprises a plate-like body (60), on the outer peripheral wall of the body (60) is 1 or more corners formed by the by outer peripheral wall first wall is formed The secondary battery according to claim 1 . The outer peripheral wall of the flange portion (51) of the electrode terminal member (5) has a shape obtained by replacing a part of the cylindrical surface with a flat surface, and the insulating seal member (6) has a flange of the electrode terminal member (5). part outer peripheral wall (51) is engaging recesses which engage relative rotation (62) is formed, the engagement recess (62) in claim wherein said second wall by the inner wall is formed of one or The secondary battery according to claim 2 . The outer peripheral wall of the flange portion (51) of the electrode terminal member (5) has one or more corners , and the insulating seal member (6) has an outer periphery of the flange portion (51) of the electrode terminal member (5). walls are engaging recesses which engage relative rotation (62) is formed, the engagement recess (62) of the inner peripheral wall by the claim 1 or claim 2 wherein the second wall is formed Secondary battery.

Images