KR101106455B1 - Cylindrical lithium ion secondary battery - Google Patents

Abstract

The present invention relates to a cylindrical lithium-ion secondary battery, the technical problem to be solved is a jelly roll (electrode roll assembly) in a variety of situations, such as a jelly roll (jelly roll) in the predetermined (can) It is to prevent the phenomenon of moving in the direction or to increase the contact resistance even when moving in a predetermined direction.

To this end, the gist of the solution according to the present invention is an electrode assembly wound with the positive electrode plate, the separator and the negative electrode plate laminated, a first connection member connected to the positive electrode plate of the electrode assembly and at the same time surrounding the upper part of the electrode assembly, and the electrode assembly. A second connecting member connected to a negative electrode plate of the electrode assembly and substantially covering the lower part of the electrode assembly, a can containing the electrode assembly, the first connecting member and the second connecting member, and a cap assembly coupled to an upper portion of the can; A cylindrical lithium ion secondary battery is disclosed in which a first connecting member is connected to a cap assembly, and a second connecting member is connected to a can.

Cylindrical secondary battery, jelly roll, electrode assembly, first connection member, second connection member

Description

Cylindrical lithium ion secondary battery

1A, 1B and 1C are a perspective view, a cross-sectional view and an exploded perspective view of a cylindrical lithium ion secondary battery according to the present invention.

2A, 2B and 2C are sectional views showing a perspective view, a partial sectional view, and a coupling method of a state in which a first connection member and a second connection member are coupled to an electrode assembly of a cylindrical lithium ion secondary battery according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100; Cylindrical lithium ion secondary battery according to the present invention

110; Electrode assembly 111; Negative plate

112; Anode plate 113; Separator

114; Negative electrode tab 115; Anode Tab

121; First connecting member 122; Conductive member

123; Insulation member 124; Electrolytic Solution Hole

125; Second connecting member 126; First challenge area

127; Second conductive region 130; Cans

131; Cylindrical face 132; Bottom

133; Beading portion 134; Crimping part

140; Cap assembly 141; gasket

142; Safety vent 143; Circuit board

143a; Wiring pattern 144; Positive temperature element

145; Anode cap 145a; Through

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical lithium ion secondary battery, and more particularly, an electrode assembly in the form of a jelly roll moves in a predetermined direction inside a can in various situations such as vibration, shock, drop, crushing, and collision. The present invention relates to a cylindrical lithium ion secondary battery which does not increase or does not increase contact resistance even if it moves.

In general, a cylindrical lithium ion secondary battery includes an electrode assembly in the form of a jelly roll, a cylindrical can in which the electrode assembly is coupled, an electrolyte solution injected into the can to allow lithium ions to move, and one side of the can. Is coupled to prevent the leakage of the electrolyte, and consists of a cap assembly and the like to prevent the separation of the electrode assembly.

Such cylindrical lithium ion secondary batteries are usually mounted on portable electronic devices such as note PCs, digital cameras, camcorders, and power tools that require large amounts of electric power because their capacity is about 2000 to 2400 mA. For example, a plurality of cylindrical lithium ion secondary batteries are connected in series and in parallel as many as necessary, and are assembled into a hard pack of a predetermined type with a protection circuit mounted therein, and are coupled to the portable electronic device for power supply. do.

In addition, in the method of manufacturing the cylindrical lithium ion secondary battery, a negative electrode plate coated with a negative electrode active material, a separator and a positive electrode plate coated with a positive electrode active material are laminated together, and then one end is bonded to a rod-shaped winding shaft, and then wound in a roughly jelly roll form. To form an electrode assembly. The electrode assembly is then inserted into a cylindrical can, and then electrolyte is injected into the cylindrical can. Finally, the cap assembly is joined to the top of the cylindrical can, thereby completing a substantially cylindrical lithium ion battery.

Meanwhile, the cylindrical lithium ion secondary battery thus completed is sampled every few hundreds or thousands, and various tests are performed by reproducing various situations similar to those that may occur during actual use of portable electronic devices. For example, the cylindrical lithium ion battery is forcibly reproduced in a state such as vibration, shock, drop, crushing and collision, thereby evaluating the performance and safety of the cylindrical lithium ion battery.

However, the conventional cylindrical lithium ion battery has been found to have a problem in that the electrode assembly is severely moved inside the can during the test process. For example, a phenomenon occurs in which the electrode assembly rotates in a predetermined direction or moves in a predetermined direction along a longitudinal direction (up and down directions) inside the can. Furthermore, the flow of the electrode assembly increases the contact resistance of various metal connection (or connection) portions, for example, the connection portion of the positive electrode tab or the negative electrode tab, thereby reducing the maximum output that the battery can output. It could be observed.

Of course, the test environment as described above can be reproduced in a similar state even when the cylindrical lithium ion battery is mounted and used in the portable electronic device. Power supply capacity is significantly worse. Furthermore, in the case of a power tool requiring an instantaneous maximum power, when the electrode assembly moves in a predetermined direction in the cylindrical lithium ion battery as described above, and thus the contact resistance increases, the instantaneous peak power decreases drastically, and ultimately, the electric tool Cannot be used properly.

The present invention is to overcome the above-mentioned conventional problems, an object of the present invention is to prevent the phenomenon of the jelly roll-shaped electrode assembly in a predetermined direction moving in the can in various situations such as vibration, shock, drop, crushing and collision In addition, the present invention provides a cylindrical lithium ion secondary battery in which contact resistance does not increase even when the electrode assembly moves.

In order to achieve the above object, a cylindrical lithium ion secondary battery according to the present invention comprises an electrode assembly wound with a positive electrode plate, a separator, and a negative electrode plate laminated, and a first electrode which is connected to the positive electrode plate of the electrode assembly and simultaneously wraps one side of the electrode assembly. A first connecting member, a second connecting member connected to the negative electrode plate of the electrode assembly and covering the other side of the electrode assembly, a can containing the electrode assembly, the first connecting member and the second connecting member, and an upper portion of the can And a cap assembly coupled to the cap assembly.

Here, the electrode assembly is electrically connected to the cap assembly through the first connecting member, and the electrode assembly is electrically connected to the can.

As described above, in the cylindrical lithium ion secondary battery according to the present invention, the first connection member and the second connection member are coupled to the upper and lower portions of the electrode assembly and their respective circumferential surfaces, thereby vibrating, impacting, dropping, crushing and colliding. In various situations, such as the electrode assembly is a structure that is difficult to move in a predetermined direction. That is, the electrode assembly is difficult to move or rotate in the up, down, left and right directions inside the can.

Furthermore, even if the electrode assembly moves inside the can, the first and second connection members that are already electrically connected to the upper and lower ends of the electrode assembly are strongly fitted so that the contact resistance does not increase. That is, even if the first connection member, the cap assembly, and the second connection member and the can move with each other, since only the mutual slides and no mechanically deformed portions, the contact resistance between the two does not increase.

Of course, the contact resistance does not increase even when the electrode assembly does not move or move inside the can in such various states, so that the maximum output voltage is kept constant at all times, and thus, the marketability of the portable electronic device employing the cylindrical lithium ion secondary battery and Reliability is also improved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily implement the present invention.

1A, 1B and 1C are a perspective view, a cross-sectional view and an exploded perspective view of a cylindrical lithium ion secondary battery according to the present invention.

As shown in FIGS. 1A, 1B and 1C, the cylindrical lithium ion secondary battery 100 according to the present invention includes an electrode assembly 110 and a first connection member coupled to an upper portion of the electrode assembly 110. 121, the second connection member 125 coupled to the bottom of the electrode assembly 110, and the electrode assembly 110, the first connection member 121, and the second connection member 125 are accommodated together. Can 130 and a cap assembly 140 covering the top of the can 130.

The electrode assembly 110 may be a negative electrode plate 111 coated with a negative electrode active material (eg, graphite, carbon, etc.), a positive electrode active material (eg, a transition metal oxide (LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _4, etc.). ) Is coated between a positive electrode plate 112 and a separator 113 positioned between the negative electrode plate 111 and the positive electrode plate 112 to prevent a short and allow only movement of lithium ions, and the negative electrode plate 111 above, The positive electrode plate 112 and the separator 113 are wound in a substantially jelly roll shape and accommodated in the cylindrical can 130. Here, the separator 113 has a width larger than that of the negative electrode plate 111 and the positive electrode plate 112 such that the upper or lower ends of the negative electrode plate 111 and the positive electrode plate 112 do not directly contact the can 130. It is formed to have. In addition, the negative electrode plate 111 may be a copper (Cu) foil, the positive electrode plate 112 may be an aluminum (Al) foil, and the separator 113 may be polyethylene (PE) or polypropylene (PP). It does not limit the material of. In addition, the negative electrode tab 114 protruding a predetermined length downwardly may be welded to the negative electrode plate 111, and the positive electrode tab 115 protruding a predetermined length upwardly may be welded to the positive electrode plate 112, and vice versa. Do. In addition, the negative electrode tab 114 may be made of nickel (Ni), and the positive electrode tab 115 may be made of aluminum (Al), but the present invention is not limited thereto.

The first connection member 121 is connected to the positive electrode plate 112 of the electrode assembly 110 and simultaneously wraps the upper circumferential surface of the upper portion of the electrode assembly 110 and the upper portion connected thereto, thereby wound up the electrode assembly 110. ) To prevent loosening and to act as an anode. Of course, the negative electrode plate 111 of the electrode assembly 110 may be connected to the first connection member 121. The configuration and role of the first connection member 121 will be described in more detail below.

The second connection member 125 is connected to the negative electrode plate 111 of the electrode assembly 110 and simultaneously wraps the lower circumferential surface of the lower portion of the electrode assembly 110 and the lower portion connected thereto, thereby wound up the electrode assembly 110. ) To prevent loosening and to act as a cathode. Of course, the positive electrode plate 112 of the electrode assembly 110 may be connected to the second connection member 125. The configuration and role of the second connection member 126 will also be described in more detail below.

The can 130 has a cylindrical shape 131 having a predetermined diameter as a substantially cylindrical shape, a bottom surface 132 having a substantially disc shape is formed at a lower portion of the cylindrical surface 131, and an upper portion thereof is opened. have. Accordingly, the electrode assembly 110 and the first connection member 121 and the second connection member 125 coupled to the upper and lower ends thereof may be directly inserted into the lower portion through the upper portion of the cylindrical can 130. . Here, the second connecting member 125 inserted below the electrode assembly 110 is directly connected to the cylindrical surface 131 and the bottom surface 132 of the can 130, thereby providing the cylindrical can 130. May act as a cathode. Therefore, even if the electrode assembly 110 is rotated in a predetermined direction inside the can 110, the second connection member 125 and the bottom surface 132 of the can 130 are only sliding with each other and are in contact with each other. The resistance does not increase. Of course, on the contrary, the second connection member 125 may be connected to the cylindrical surface 131 and the bottom surface 132 of the can 130, in which case the cylindrical can 130 may operate as an anode. . The cylindrical can 130 may be formed of steel, stainless steel, aluminum, or an equivalent thereof, but the material is not limited thereto. In addition, the region in contact with the inner wall of the cylindrical surface 131 constituting the can 130 is not the electrode assembly 110 but the first connection member 121 and the second connection member 125 that surround the can 130. Accordingly, the diameter of the can 130 is the same as that of the conventional art, and the diameter of the electrode assembly 110 is also the same as that of the prior art. The first connection member 121 and the first connection member 121 are formed on the outermost circumferential surface of the electrode assembly 110. Since the two connection members 125 are coupled, the electrode assembly 110 is vertically moved inside the can 130 by the first connection member 121 and the second connection member 125. It is difficult to move left and right. In other words, the first connecting member 121 and the second connecting member 125 are in contact with the cylindrical surface 131 of the can 130 to prevent the up, down, left and right flow of the electrode assembly 110. Done.

The cap assembly 140 has an insulating gasket 141 coupled to an upper region of the cylindrical can 130 (that is, an upper region of the first connection member 121) in a substantially ring shape, and the insulating gasket 141. The conductive safety vent 142 may be combined. Here, the first connection member 121 may be in contact with the safety vent 142. Therefore, even if the electrode assembly 110 is rotated in a predetermined direction inside the can 110, the safety vent 142 and the first connection member 121 are only sliding with each other so that the contact resistance does not increase. do. As is well known, the safety vent 142 may be deformed or ruptured when the pressure inside the can 130 rises to damage the circuit board 143 to be described below or to release gas to the outside. In addition, the upper portion of the safety vent 142 is further located a circuit board 143 that is broken or destroyed when the deformation of the safety vent 142, the current is cut off, the upper portion of the circuit board 143 A positive temperature element 144 is located where the current is cut off. In addition, an upper portion of the positive temperature element 144 provides a positive voltage (or negative voltage) to the outside, and a conductive positive electrode cap 145 (or negative electrode cap) in which a plurality of through holes 145a are formed to facilitate gas discharge is provided. It is located further. Of course, the above-described safety vent 142, the circuit board 143, the positive temperature element 144 and the positive electrode cap 145 are all mounted inside the insulating gasket 141, so as to be compared with the cylindrical can 130. Direct short is prevented. In addition, a wiring pattern 143a is formed on the surface of the circuit board 143. The wiring pattern 143a is naturally broken when the circuit board 143 is broken or broken.

On the other hand, the cylindrical can 130 has a beading part 133 recessed therein is formed at the lower portion of the cylindrical assembly 130 so that the cap assembly 140 is not separated outward. The upper portion is formed with a crimping part (134) bent inwardly. The beading part 133 and the crimping part 134 serve to firmly fix and support the cap assembly 140 to the cylindrical can 130, and also to prevent the electrolyte to be leaked to the outside.

In addition, an electrolyte (not shown) is injected into the cylindrical can 130, and lithium ions generated by electrochemical reactions in the negative electrode plate 111 and the positive electrode plate 112 inside the battery during charge and discharge. It serves to make this moveable. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of lithium salts and high purity organic solvents. In addition, the electrolyte may be a polymer using a polymer electrolyte, and the type of the electrolyte is not limited thereto.

In this manner, in the present invention, even if the electrode assembly 110 moves inside the can 130, the first connection member 121 and the second connection member 121 which are already electrically connected to the upper and lower ends of the electrode assembly 110. Since the connection member 125 is firmly fitted, the contact resistance does not increase. That is, even if the safety vent 142 of the first connecting member 121 and the cap assembly 140 and the bottom surface 132 of the second connecting member 125 and the can 130 move with each other, only the mutual slides are allowed. Since there is no mechanically deformed portion, the contact resistance between the two does not increase.

2A, 2B and 2C are sectional views showing a perspective view, a partial sectional view, and a coupling method of a state in which a first connection member and a second connection member are coupled to an electrode assembly of a cylindrical lithium ion secondary battery according to the present invention.

As shown in FIGS. 2A, 2B and 2C, the first connection member 121 and the second connection member 125 are coupled to the upper and lower portions of the electrode assembly 110, respectively.

First, the first connection member 121 is connected to the positive electrode plate 112 of the electrode assembly 110 and at the same time wraps the circumferential surface of the upper portion of the electrode assembly 110 and the upper portion connected thereto, whereby the wound electrode assembly ( It prevents the loosening phenomenon of 110 and at the same time serves as an anode. More specifically, the first connection member 121 includes a conductive member 122 having a substantially disk shape, and an insulating member 123 coupled to an outer circumference of the conductive member 122. The conductive member 122 is positioned substantially above the electrode assembly 110, which is electrically connected to the positive electrode tab 115 of the electrode assembly 110. Here, the connection of the conductive member 122 and the positive electrode tab 115 may be a conventional resistance welding, laser welding, ultrasonic welding or the equivalent thereof, and the present invention does not limit the welding method. In addition, the conductive member 122 may be formed of any one selected from aluminum or its equivalent, but the material is not limited thereto. In addition, the insulating member 123 is coupled to an outer portion of the conductive member 122 and connected to the upper portion and the upper portion of the electrode assembly 110 to surround the circumferential surface of the electrode assembly 110. That is, the insulating member 123 has a portion of the region is located above the electrode assembly 110, the remaining region is in the form of a cylindrical pipe wraps around the upper circumferential surface of the electrode assembly 110. The reason why the insulating member 123 is formed on the outer side of the conductive member 122 is to prevent the phenomenon in which the conductive member 122 is in direct contact with the can 130. In addition, the insulating member 123 may be formed of any one of a PP material or an equivalent thereof that does not chemically react with the electrolyte solution injected into the can 130, but the material of the insulating member is not limited thereto. Furthermore, at least one hole 124 is formed in the conductive member 122 or the insulating member 123 adjacent thereto, so that the electrolyte easily flows into the electrode assembly 110 in the electrolyte injection process. It is supposed to go.

The second connection member 125 is connected to the negative electrode plate 111 of the electrode assembly 110 and simultaneously wraps the lower circumferential surface of the lower portion of the electrode assembly 110 and the lower portion connected thereto, thereby wound up the electrode assembly 110. ) To prevent loosening and to act as a cathode. More specifically, the second connection member 125 may include a first conductive region 126 having a substantially disc shape, and a second conductive region 127 integrally formed at an outer circumference of the first conductive region 126. have. The first conductive region 126 is located substantially below the electrode assembly 110, which is electrically connected to the negative electrode tab 114 of the electrode assembly 110. Here, the connection of the first conductive region 126 and the negative electrode tab 145 may be conventional resistance welding, laser welding, ultrasonic welding, or an equivalent thereof, and the present invention does not limit the welding method. In addition, the first conductive region 126 may be formed of any one selected from nickel, copper, iron, or equivalents thereof, but the material is not limited thereto. In addition, the second conductive region 127 is integrally formed at the outer side of the first conductive region 126 and simultaneously surrounds the lower circumferential surface of the electrode assembly 110. That is, the second conductive region 126 has a cylindrical pipe shape to surround the lower circumferential surface of the electrode assembly 110. The second conductive region 127 may also be made of the same material as the first conductive region 126. The second conductive region 127 is electrically connected to the can 130 directly by the structure. Rescue. Of course, the second conductive region 127 may also be formed of a conventional insulator instead of a conductor, and the second conductive region 127 is not limited to a conductor or an insulator.

In addition, although the first connection member 121 and the second connection member 125 are spaced apart from each other by a predetermined distance in a state where they are fitted to the electrode assembly 110 in the drawing, the first connection member 121 and the second connection member 125 are separated from each other. It is to be understood that the connecting members 125 may be in contact with each other on the circumferential surface of the electrode assembly 110. Furthermore, it should be noted that, as described above, the second conductive region 127 of the second connection member 125 may be an insulator instead of a conductor.

As described above, the cylindrical lithium ion secondary battery according to the present invention is coupled to the upper and lower portions of the electrode assembly, and the first connecting member and the second connecting member on their respective circumferential surfaces, thereby vibrating, impacting, dropping, crushing and In various situations such as a collision, the electrode assembly may be difficult to flow in a predetermined direction. That is, the electrode assembly is difficult to move or rotate in the up, down, left and right directions inside the can.

Furthermore, even if the electrode assembly moves inside the can, the first and second connection members that are already electrically connected to the upper and lower ends of the electrode assembly are strongly fitted so that the contact resistance does not increase. That is, even if the first connection member, the cap assembly, and the second connection member and the can move with each other, since only the mutual slides and no mechanically deformed portions, the contact resistance between the two does not increase.

Of course, the contact resistance does not increase even when the electrode assembly does not move or move inside the can in such various states, so that the maximum output voltage is kept constant at all times, and thus, the marketability of the portable electronic device employing the cylindrical lithium ion secondary battery and Reliability is also improved.

What has been described above is just one embodiment for implementing the cylindrical lithium ion secondary battery according to the present invention, the present invention is not limited to the above embodiment, as claimed in the following claims of the present invention Without departing from the gist of the present invention, one of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (6)

An electrode assembly wound in a state in which a positive electrode plate, a separator, and a negative electrode plate are stacked; A first connection member connected to the positive electrode plate of the electrode assembly and surrounding one side of the electrode assembly; A second connection member connected to the negative electrode plate of the electrode assembly and surrounding the other side of the electrode assembly; A can containing the electrode assembly, the first connection member, and the second connection member; Cylindrical lithium ion secondary battery comprising a cap assembly coupled to the top of the can. The method of claim 1, wherein the first connection member A conductive member positioned on the electrode assembly and connected to the positive electrode plate and the positive electrode tab of the electrode assembly; And, And a cylindrical lithium ion secondary battery coupled to an outer portion of the conductive member and connected to an upper portion of the electrode assembly and to the outer surface of the electrode assembly to surround the circumferential surface of the electrode assembly. The cylindrical lithium ion secondary battery of claim 2, wherein at least one electrolyte injection hole is further formed in the conductive member or the insulating member. The method of claim 1, wherein the second connection member A first conductive region positioned below the electrode assembly and connected to the negative electrode plate and the negative electrode tab of the electrode assembly; And, And a second conductive region formed outside the first conductive region and connected to a lower portion of the electrode assembly and surrounding the circumferential surface of the electrode assembly. The cylindrical lithium ion secondary battery of claim 2, wherein the first connection member is electrically connected to the cap assembly. The cylindrical lithium ion secondary battery of claim 4, wherein the second connection member is electrically connected to the can with the first conductive region and the second conductive region.

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