KR20110048470A - Secondary Battery and Battery Pack Using the Same - Google Patents

Abstract

PURPOSE: A secondary battery is provided to break the structural connection between an electrode terminal and an electrode tab, thereby enhancing the reliability of a battery pack. CONSTITUTION: A secondary battery comprises: an electrode assembly(130) consisting of a first electrode(131), second electrode(132) and separator(133); a case(120) for receiving the electrode assembly; an electrode terminal connected to the first electrode; and an electrode tab connected to the first electrode and extending out of the case, wherein the electrode tab is arranged to separate from the first electrode if the case is deformed in the state where the lead tab is in contact with the case.

Description

Secondary battery and battery pack using same {SECONDARY BATTERY AND BATTERY PACK USING THE SAME}

The present invention relates to a rechargeable battery and a battery pack using the same.

In general, a secondary battery refers to a rechargeable battery, unlike a primary battery that cannot be charged, and is widely used in electronic devices such as a mobile phone, a notebook computer, a camcorder, and the like.

Among various types of secondary batteries, lithium secondary batteries are widely used because of their high operating voltage and high energy density per unit weight. Lithium secondary batteries are manufactured in various shapes, and typical shapes include rectangular, cylindrical, and pouch types.

In the secondary battery, due to overcharging and overdischarging or internal short circuit and other overheating, the internal temperature may increase and the internal gas pressure may be excessively high. The secondary battery is more likely to operate outside the normal charge / discharge operation under such a situation. In addition, the case of the secondary battery is exposed to a swelling phenomenon swelling due to gas pressure.

The present invention provides a secondary battery and a battery pack using the same, which can open a circuit using a swelling phenomenon in a manner different from the conventional art.

The present invention provides a secondary battery and a battery pack using the same to structurally block an electrical connection between an electrode assembly and a lead tab when swelling occurs so that a circuit can be opened to stop charging and discharging.

According to an embodiment of the present invention, a secondary battery includes an electrode assembly including a first electrode and a second electrode, and a separator positioned between the first electrode and the second electrode, a case in which the electrode assembly is accommodated, An electrode terminal electrically connected to the first electrode and

A lead tab extending in the case to the outside of the case and electrically connected to the first electrode through the electrode terminal, wherein the lead tab is in a state in which the lead tab is in contact with the case; In the case of deformation, it is formed to be separated from at least a part of the electrode terminal so that the electrical connection is cut off from the first electrode.

In addition, the secondary battery of the present invention further includes an adhesive member for adhering the lead tab to the electrode terminal, wherein the adhesive member has a through hole, and the lead tab is electrically connected to the electrode terminal through the through hole. It can be formed to be connected.

In addition, the secondary battery of the present invention further includes a coupling member for coupling a portion of the lead tab to the case, wherein the coupling member is a contact position between the lead tab and the electrode terminal than a contact position between the case and the lead tab. It can be formed closer to.

In addition, in the secondary battery of the present invention, the electrode terminal and the lead tab may be electrically connected by spot welding. In addition, the electrode terminal and the lead tab may be electrically connected to each other in at least one contact.

In addition, the secondary battery of the present invention further includes an adhesive member for adhering the lead tab to an electrode terminal, wherein the lead tab includes at least one contact on the first side of the adhesive member and the side opposite to the first side. It may be formed to be electrically connected to the electrode terminal through at least one other contact on the second side of the adhesive member.

In addition, the secondary battery of the present invention, the case further includes a deformation portion, the lead tab is bonded to the deformation portion, the lead tab may be formed to be electrically separated from the first electrode as the deformation portion is deformed. have. In this case, the deformable portion may be formed as an inclined surface between two parallel sidewalls of the case.

In addition, the secondary battery of the present invention may be formed by further comprising a groove at least partially surrounding the contact region in which the conductive terminal located between the electrode terminal and the lead tab is located.

In addition, in the secondary battery of the present invention, the case may include a deformation portion, the lead tab may be attached to the deformation portion, and the contact region may be formed to be separated from the electrode terminal when the deformation portion is deformed. In this case, the groove may be formed to completely surround the contact region, or may be formed to partially surround the contact region at an edge of the electrode terminal.

In addition, the secondary battery of the present invention may be formed of a material in which the electrode terminal has an electrical resistance of 10 mPa or less.

In addition, the secondary battery of the present invention may further include a coupling member for coupling the lead tab to the inner surface of the case, and may further include a support member for coupling the electrode terminal to the inner surface of the case. In addition, the adhesive strength between the electrode terminal and the lead tab may be formed to be lower than the adhesive strength between the case and the lead tab.

In addition, the secondary battery of the present invention includes a first plate and a second plate on which the electrode terminals are stacked, the strength of the first plate is lower than the strength of the second plate, the electrical conductivity of the first plate It is higher than the electrical conductivity of the second plate, the first plate may be formed to be electrically connected to the lead tab through the conductive contact.

In addition, the battery pack of the present invention includes a plurality of secondary batteries and a circuit board for controlling the secondary batteries, wherein at least one of the secondary batteries includes a first electrode and a second electrode, and the first electrode and the second electrode. An electrode assembly including a separator positioned therebetween, a case in which the electrode assembly is accommodated, an electrode terminal electrically connected to the first electrode, and extending out of the case within the case, through the electrode terminal And a lead tab electrically connected to the first electrode, wherein the lead tab disconnects the electrical connection from the first electrode when the case is deformed while the lead tab is in contact with the case. The lead tab is formed so as to be separated from at least a portion of the at least one lead battery of the secondary battery. It may be formed to be connected to.

The secondary battery and the battery pack having the same according to the present invention configured as described above allow the electrode terminal and the lead tab to be separated by the deformation of the pouch case inflated according to the pressure of the gas at the time of swelling.

As a result, when the swelling occurs, the electrical connection between the electrode assembly and the lead tab is structurally blocked to increase the reliability of the secondary battery and the battery pack having the same.

1 is a perspective view of a battery pack according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating one of a plurality of secondary batteries forming the battery pack of FIG. 1; FIG.
3 is a cross-sectional view taken along the line III-III of FIG. 2;
Figure 4 is an exploded perspective view showing a structure for forming the connecting portion of FIG.
FIG. 5 is a cross-sectional view illustrating a change caused by swelling in the secondary battery of FIG. 3. FIG.
FIG. 6 is a simplified process diagram illustrating a process in which the swelling and circuit open illustrated in FIG. 5 occur. FIG.
7 is a perspective view illustrating a welding method of a positive electrode terminal and a first lead tab according to another exemplary embodiment of the present invention.
8 is a cross-sectional view illustrating a coupling relationship between a positive electrode terminal and a first lead tab according to another exemplary embodiment of the present invention.
9 is a perspective view of the positive terminal of FIG. 8;
10 is a perspective view showing a positive terminal according to another embodiment of the present invention.
11 is a cross-sectional view illustrating a bonding state of a positive electrode terminal and a first lead tab according to another embodiment of the present invention.

Hereinafter, a secondary battery and a battery pack using the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a battery pack 100 according to an embodiment of the present invention.

Referring to FIG. 1, the battery pack 100 includes a plurality of secondary batteries 110, a connection part 200, a circuit board 300, and a sensing element 400.

The plurality of secondary batteries 110 are stacked such that adjacent main surfaces thereof face each other. That is, side surfaces of the secondary batteries 110 are parallel to each other. The charge / discharge capacity of the battery pack 100 increases in proportion to the increase in the number of secondary batteries 110. The battery pack 100 requires a large capacity than a small device, for example, a portable terminal, which has sufficient power supply with only a single secondary battery 110, and a large device, for example, a hybrid electric vehicle (HEV) or an electric vehicle ( EV) may also be used. However, the present invention is not limited thereto. The secondary battery 110 includes lead tabs 140 that are exposed to the outside.

The connection part 200 may electrically connect ones of the lead tabs 140 having the same polarity to each other. That is, the lead tabs 140 having the positive polarity are electrically connected to each other by the connection part 200, and the lead tabs 140 having the negative polarity are electrically connected to each other by the connection part 200. The connection part 200 may include connecting plates 210 disposed between adjacent secondary batteries 110 and connecting rods 220 electrically connected to the outermost ones of the connecting plates 210. have. The connection part 200 may be formed of a conductive metal material, for example, copper, nickel, or aluminum having excellent electrical conductivity.

The circuit board 300 is for controlling charging and discharging of the plurality of secondary batteries 110, and only one of the plurality of secondary batteries 110 may be provided. The circuit board 300 may be electrically connected to the secondary batteries 110 through the connecting rod 220. As the plurality of secondary batteries 110 are controlled by the one circuit board 300, the battery pack 100 may be configured to be simpler than a circuit for each secondary battery 110.

The circuit board 300 is electrically connected to the sensing element 400 inserted into each lead tab 140 or coupled to the surface of the lead tab 140. The sensing element 400 is, for example, a wire, and allows the circuit board 300 to detect a change in voltage in each secondary battery 110. The circuit board 310 may further include a display 310 in the embodiment of FIG. 1. The display 310 may output content related to the result detected by the sensing element 400. This output will be primarily useful in testing the battery pack 100.

FIG. 2 is a perspective view illustrating one of a plurality of secondary batteries 110 constituting the battery pack of FIG. 1.

Referring to FIG. 2, the secondary battery 110 includes a case 120, an electrode assembly 130 (see FIG. 3), and a lead tab 140. The case 120 may be formed as a pouch case and will be described below with reference to the pouch case.

The pouch case 120 may be formed to have a substantially rectangular parallelepiped shape. The pouch case 120 is formed of a thin metal plate such as aluminum. When resin is applied to opposite surfaces of the thin plate, the pouch case 120 may be electrically insulated from the material in contact with the surfaces.

One side of the pouch case 120 may be formed as an inclined surface 121. The end region or sealing region 122 extends from the inclined surface 121 to cover or clamp the lead tab 140.

The electrode assembly 130 is accommodated together with the electrolyte in the internal space S (see FIG. 3) formed by the pouch case 120. One end of the lead tab 140 is connected to (eg, electrically connected to) the electrode assembly 130, and the other end extends to be exposed to the outside of the pouch case 120.

The lead tab 140 includes a first lead tab 141 and a second lead tab 142 spaced apart from each other along the width direction of the sealing region 122. The first lead tab 141 may be electrically connected to the positive electrode plate or the negative electrode plate to be electrically positive or negative electrode. The second lead tab 142 may be electrically connected to the negative electrode plate or the positive electrode plate to have a polarity electrically opposite to that of the first lead tab 141.

3 is a cross-sectional view taken along the line III-III of FIG. 2.

Referring to FIG. 3, the electrode assembly 130 includes a first electrode plate 131 and a second electrode plate 132, and a separator 133 disposed between them 131 and 132. The first electrode plate 131 may be formed as a positive electrode plate, and the second electrode plate 132 may be formed as a negative electrode plate. In addition, the first electrode plate 131 and the second electrode plate 132 may be formed oppositely. Hereinafter, the first electrode plate 131 is described as a positive electrode plate, and the second electrode plate 132 is formed of a negative electrode plate.

The positive electrode plate 131 is formed by coating a positive electrode active material layer on the surface of the positive electrode current collector, and the negative electrode plate 132 is formed by coating a negative electrode active material layer on the surface of the negative electrode current collector.

The positive electrode current collector of the positive electrode plate 131 is formed of a conductive metal material to collect electrons from the positive electrode active material layer and move them to an external circuit during charging. The cathode active material layer is prepared by mixing a cathode active material, a conductive material and a binder, and is formed by coating a predetermined thickness on the cathode current collector.

The negative electrode current collector of the negative electrode plate 132 is formed of a conductive metal material to collect electrons from the negative electrode active material layer and discharge the electrons to an external circuit during discharge. The negative electrode active material layer is prepared by mixing a negative electrode active material, a conductive material and a binder, and is formed by coating a predetermined thickness on the negative electrode current collector.

The separator 133 is an insulating material, and functions to electrically insulate the positive electrode plate 131 and the negative electrode plate 132.

The positive electrode plate 131, the separator 133, and the negative electrode plate 132, which are sequentially stacked, may be wound or stacked in a jelly role shape to form an accommodation space as an electrode assembly 130. S) is arranged. When the electrolyte is injected into the accommodation space S, the electrode assembly 130 is in a state impregnated with the electrolyte.

The conductive positive electrode terminal 135 extends from the positive electrode plate 131 of the electrode assembly 130. The positive electrode terminal 135 may be formed of a material having a resistance of about 10 mΩ or less so that current of a level required for a medium and large battery may flow. The positive terminal 135 is connected to the conductive first lead tab 141. Electrical connection between the positive electrode terminal 135 and the first lead tab 141 is made by the conductive connection 145. In the following, the positive terminal or the negative terminal is described as an electrode terminal when the distinction of polarity is not necessary.

The first lead tab 141 may include two portions of the pouch case 120 forming the sealing region 122, that is, the case lower part 123 and the upper case 124 are sealed to each other. 123, 124). The inner space S is sealed while accommodating the electrode assembly 130 and the electrolyte by sealing the lower case and the upper case 123 and 124.

As the first lead tab 141 is positioned at a level higher than the level at which the anode terminal 135 is positioned, the case lower portion 123 of the sealing region 122 is positioned at the lowest level of the outer surface of the pouch case 120. It may be located at a level that is elevated stepwise relative to it.

The support member 161 may be positioned between the positive electrode terminal 135 and the pouch case 120 to support and fix the positive electrode terminal 135 with respect to the pouch case 120. The support member 161 may be formed of, for example, an insulating tape.

The coupling member 162 is disposed between the first lead tab 141 and the pouch case 120 to couple at least a portion of the first lead tab 141 to the inner surface of the pouch case 120. The coupling member is formed closer to the contact position between the first lead tab 141 and the positive electrode terminal 135 than the contact position between the pouch case 120 and the first lead tab 141. The coupling member 162 is a good bonding strength, for example, may be formed of a polypropylene film or polyethylene film.

Although both the support member 161 and the coupling member 162 have been described above, only the coupling member 162 may be provided if the coupling force between the electrode assembly 130 and the positive electrode terminal 135 is strong. This is because the role of the support member 161 is relatively relative to the operation in which the first lead tab 141 is deformed away from the positive electrode terminal 135 together with the pouch case 120 by the coupling member 162 during swelling. Because it is small.

An adhesive member, for example, an insulating tape 150 may be additionally disposed between the positive electrode terminal 135 and the first lead tab 141. Opposite surfaces of the adhesive member 150 are bonded to opposite surfaces of the positive electrode terminal 135 and the lead tab 140, respectively. Opposite surfaces (main surfaces) of the positive electrode terminal 135 and the first lead tab 141 may be disposed to be spaced apart from each other by the adhesive member 150.

The adhesive member 150 allows the positive electrode terminal 135 and the first lead tab 141 to be structurally firmly coupled (adhered). Accordingly, even when the secondary battery 110 is subjected to an impact or an external force during normal operation, the possibility of disconnection of the connection part 145 may be maintained to a lower level or less by the adhesive member 150. This ensures a stable electrical connection between the electrode assembly 130 and an external circuit when the electrode assembly 130 is in normal operation.

Insulation tapes 171 and 172 may be disposed between opposite surfaces of the first lead tab 141 and the sealing region 122 of the pouch case 120, respectively. The insulating tapes 171 and 172 insulate between the first lead tab 141 and the sealing region 122.

In the above, only the connection structure of the positive electrode terminal 135 and the first lead tab 141 has been described, but the negative electrode terminal (which is connected to the negative electrode plate 132 and extends corresponding to the second lead tab 142) and the second lead The tab 142 may also have a connection structure in the same manner.

4 is an exploded perspective view illustrating a structure for forming the connecting portion 145 of FIG. 3.

Referring to FIG. 4, the through hole 151 is formed in the central region of the adhesive member 150 disposed between the anode terminal 135 and the first lead tab 141. The adhesive member 150 is bonded to the opposite surfaces of the positive electrode terminal 135 and the first lead tab 141 in the remaining region except for the region where the through hole 151 is formed. Accordingly, the first lead tab 141 is electrically connected to the positive electrode terminal 135 through at least one contact on the first side of the adhesive member and at least one contact on the second side opposite to the first side. do.

In the contact regions 135 ′ and 141 ′ of the anode terminal 135 and the first lead tab 141 corresponding to the through hole 151, electrodes W1 and W2 for spot welding are disposed. Can be. Specifically, the first electrode W1 whose end is in contact with the contact region 135 ′ and the second electrode W2 whose end is in contact with the other region 141 ′ are disposed to be placed on a single line. To press the contact regions 135 'and 141'. The current flowing through the positive electrode terminal 135 and the first lead tab 141 by the first and second electrodes W1 and W2 for a short time generates Joule heat. The joule rows cause the opposite surfaces of the positive electrode terminal 135 and the contact regions 135 'and 141' of the first lead tab 141 to melt and adhere to each other. The positive terminal 135 and the lead tab 141 are electrically connected to at least one conductive contact. The contact regions 135 ′ and 141 ′ in which the conductive contacts are located are attached to each other to form a conductive connection 145. The conductive connecting portion 145 may be formed in plural numbers depending on the number of times spot welding is made (for each different position). In order to increase the bonding (welding) strength between the positive electrode terminal 135 and the first lead tab 141, the number of spot welding (for example, the position of the spot welding) may be increased.

5 is a cross-sectional view illustrating a state in which the secondary battery 110 of FIG. 3 is changed as swelling occurs, and FIG. 6 is a simplified process diagram illustrating a process in which swelling and circuit opening illustrated in FIG. 5 occur.

Referring to FIGS. 5 and 6, when the internal temperature of the secondary battery 110 rises due to overcharge and overdischarge and the gas pressure inside the battery rises above a certain level, the pouch case 120 swells (swelling). ) May occur. The pouch case 120 is mainly inflated at both ends along the longitudinal direction, and among them, the inclined surface 121 will be most expanded to the outside. Therefore, the inclined surface 121 of the pouch case 120 acts as a deformation part. That is, the deformation part is formed as an inclined surface that is a surface inclined between two parallel sidewalls of the pouch case 120. In addition, the first lead tab 141 is coupled to an inner side surface of the inclined surface 121 that is a deformation portion.

When the inclined surface 121 expands to the outside, the end region located in the internal space S of the first lead tab 141 coupled to the inclined surface 121 by the coupling member 162 may also be bent outwardly and deformed. do. The deformation causes the end region of the first lead tab 141 to be pulled away from the positive terminal 135. The first lead tab 141 may be separated from the positive electrode terminal 135 when the gas pressure exceeds a predetermined level. This separation will mainly occur as the connection 145 is broken and divided into two parts 145a and 145b.

When the two portions 145a and 145b are separated from each other, the electrical connection between the positive terminal 135 and the first lead tab 141 is structurally released. This further allows the electrode assembly 130 and the external circuit to be electrically open.

Breakage of the connection portion 145 may occur by the above mechanism only when the coupling member 162 is separated from the pouch case 120 or the first lead tab 141. To this end, the strength by the welding of the positive electrode terminal 135 and the first lead tab 141 (the strength of the connecting portion 145) is applied to the pouch case 120 and the first lead tab 141 of the coupling member 162. Should be less than the bond strength. For example, when the former is 2.5 kgf or less, the latter may be 3.0 kgf or more. The latter strength is a level at which peeling does not occur even when the coupling member 162 is stretched with respect to the pouch case 120 or the first lead tab 141 at a rate of 50 mm / min.

In addition, when a connection between any one of the plurality of secondary batteries 110 and an external circuit is opened, it will be sensed by the sensing element 400 (see FIG. 1). The circuit board 300 connected to the sensing device 400 may control other secondary batteries 110 or may notify that one of the above secondary batteries 110 is in a malfunction state. To this end, the circuit board 300 may include a display 310 (FIG. 1) or light emitting means. 1 illustrates a case in which the display 310 indicates that the secondary battery 110 is malfunctioning.

Referring to the operation of the adhesive member 150 in connection with the breaking of the connecting portion 145 when the adhesive member 150 is employed as follows. Heat caused by the internal temperature rise of the secondary battery 110 is concentrated on the positive electrode terminal 135 and the first lead tab 141. As the temperature increases, the adhesive member 150 that receives heat by the positive electrode terminal 135 or the like decreases its adhesive performance. This prevents the adhesive member 150 from firmly coupling the positive electrode terminal 135 and the first lead tab 141 after a time point when the secondary battery 110 is abnormally operated. Therefore, unlike the case where the secondary battery 110 operates normally, the adhesive member 150 hardly affects the separation of the positive electrode terminal 135 and the first lead tab 141 in the case of abnormal operation. do.

7 is a perspective view illustrating a method of welding the positive electrode terminal 135 and the first lead tab 141 according to another exemplary embodiment of the present invention.

Referring to FIG. 7, unlike the embodiment described with reference to FIG. 4, no through hole is formed in the adhesive member 150 ′. Instead, the adhesive member 150 ′ is formed smaller than in the previous embodiment, and is attached to opposite surfaces of the positive electrode terminal 135 and the first lead tab 141.

As the adhesive member 150 'is disposed at the center of the corresponding region of the positive terminal 135 and the first lead tab 141, the edge of the corresponding region is directed to the regions 135 "and 141" for welding. Can be used. In this embodiment, the regions 135 " and 141 " for welding are formed in portions adjacent to both sides of the adhesive member 150 ', respectively.

According to this, spot welding may be performed twice using the two electrodes W1 and W2. Thereby, the positive terminal 135 and the first lead tab 141 will have portions (see connection portion 145 of FIG. 3) connected to each other at two locations.

8 is a cross-sectional view illustrating a coupling relationship between the positive electrode terminal 135a and the first lead tab 141 according to another embodiment of the present invention, and FIG. 9 is a perspective view of the positive electrode terminal 135a of FIG. 8.

8 and 9, the anode terminal 135a and the first lead tab 141 are coupled to each other by the conductive connecting portion 145 formed by welding. Furthermore, as in the previous embodiment, the adhesive member 150 may be further disposed between the positive electrode terminal 135a and the first lead tab 141.

A groove 1351 is formed in the positive terminal 135a. The groove 1351 is in the form of a closed curve and may be formed to have a substantially circular shape as illustrated. The conductive connection 145 is positioned in the contact region 1352 defined by the groove 1351. That is, the groove completely surrounds the contact area in which the conductive contact formed between the anode terminal and the first lead tab is located. Therefore, on the other hand, when the deformation portion that is the inclined surface 121 of the pouch case 120 is deformed, the contact region 1352 is separated from the positive terminal 135.

On the other hand, even when the connection part 145 is not broken at the time of swelling of the pouch case 120, the positive electrode terminal 135a and the first lead tab 141 are defined by the groove 1351 of the positive electrode terminal 135c. The contact regions 1352 are separated from the rest of the positive terminal 135a, so that they may be separated from each other.

10 is a perspective view illustrating a positive electrode terminal 135b according to another embodiment of the present invention.

Referring to FIG. 10, the groove 1353 forms a part of a closed curve, and the open end extends to one end of the positive electrode terminal 135b. The conductive connection 145 is positioned in the contact region 1354 defined by the groove 1353 and the one end. That is, the groove 1353 partially surrounds the contact area 1354. According to this configuration, the contact region 1354 may be separated from the remaining region of the positive terminal 135b more easily than the contact region 1352 of the previous embodiment.

11 is a cross-sectional view illustrating a coupling state of the positive electrode terminal 135c and the first lead tab 141 according to another embodiment of the present invention.

Referring to FIG. 110, the positive electrode terminal 135c may be configured as a clad in which the first plate 1356 and the second plate 1357 are stacked and bonded to each other. The first plate 1356 has a lower strength but a higher electrical conductivity than the second plate 1357. The first lead tab 141 is connected to the first plate 1356 having high electrical conductivity by the connecting portion 145. The second plate 1357 increases the overall rigidity of the positive electrode terminal 135c.

The second plate 1357 has an area 1358 opened at the central portion of the main surface. The connecting portion 145 is located in this area 1358.

According to this configuration, the strength can be increased without lowering the electrical conductivity of the positive electrode terminal 135c. This increases the possibility that the positive electrode terminal 135c retains the magnetic field without being dragged by the first lead tab 141 when the first lead tab 141 is deformed. This allows the first lead tab 141 to be more easily separated from the positive terminal 135c.

Further, one portion of the positive lead terminal 141 and the connecting portion 145 and the positive terminal 135c corresponding to the open area 1358 is more easily removed from the remaining portion of the positive electrode terminal 135c during swelling. It may be separated.

The secondary battery and the battery pack according to the present invention are not limited to the configuration and operation of the embodiments described above. The embodiments may be configured so that all or some of the embodiments may be selectively combined so that various modifications may be made.

100: battery pack 110: secondary battery
200: connection portion 300: circuit board
400: sensing element

Claims (18)

An electrode assembly comprising a first electrode and a second electrode and a separator positioned between the first electrode and the second electrode;
A case accommodating the electrode assembly;
An electrode terminal electrically connected to the first electrode;
A lead tab extending out of the case and electrically connected to the first electrode through the electrode terminal;
And the lead tab is formed to be separated from at least a portion of the electrode terminal so that the electrical connection is cut off from the first electrode when the case is deformed while the lead tab is in contact with the case. The method of claim 1,
An adhesive member for adhering the lead tab to the electrode terminal, the adhesive member having a through hole,
And the lead tab is formed to be electrically connected to the electrode terminal through the through hole. The method of claim 1,
And a coupling member for coupling a portion of the lead tab to the case, wherein the coupling member is formed closer to the contact position of the lead tab and the electrode terminal than the contact position of the case and the lead tab. Secondary battery. The method of claim 1,
And the electrode terminal and the lead tab are electrically connected by spot welding. The method of claim 1,
And the electrode terminal and the lead tab are electrically connected to each other at least one contact. The method of claim 1,
Further comprising an adhesive member for adhering the lead tab to the electrode terminal,
The lead tab is electrically connected to the electrode terminal via at least one contact on the first side of the adhesive member and at least another contact on the second side of the adhesive member opposite the first side. Secondary battery. The method of claim 1,
The case further includes a deformable portion, wherein the lead tab is bonded to the deformable portion, the lead tab is a secondary battery characterized in that it is formed to be electrically separated from the first electrode as the deformable portion is deformed. The method of claim 7, wherein
And the deformable portion has a surface inclined between two parallel sidewalls of the case. The method of claim 1.
And the electrode terminal further includes a groove at least partially surrounding a contact region in which a conductive contact located between the electrode terminal and the lead tab is located. The method of claim 9,
The case includes a deformable portion, wherein the lead tab is attached to the deformable portion, and the contact region is formed to be separated from the electrode terminal when the deformable portion is deformed. The method of claim 9,
The groove is secondary battery, characterized in that formed to completely surround the contact area. The method of claim 9,
The groove is secondary battery, characterized in that formed to partially surround the contact area at the edge of the electrode terminal. The method of claim 1,
The electrode terminal is a secondary battery, characterized in that formed of a material having an electrical resistance of 10mPa or less. The method of claim 1,
Secondary battery, characterized in that it further comprises a coupling member for coupling the lead tab to the inner surface of the case. The method of claim 14,
And a support member for coupling the electrode terminal to an inner surface of the case. The method of claim 14,
The adhesive strength between the electrode terminal and the lead tab is lower than the adhesive strength between the case and the lead tab. The method of claim 1,
The electrode terminal includes a first plate and a second plate laminated, the strength of the first plate is lower than the strength of the second plate, the electrical conductivity of the first plate is less than the electrical conductivity of the second plate And the first plate is electrically connected to the lead tab through the conductive contact. Many secondary batteries and
It includes a circuit board for controlling the secondary batteries,
At least one secondary battery
An electrode assembly comprising a first electrode and a second electrode and a separator positioned between the first electrode and the second electrode;
A case accommodating the electrode assembly;
An electrode terminal electrically connected to the first electrode;
A lead tab extending out of the case and electrically connected to the first electrode through the electrode terminal;
The lead tab is formed to be separated from at least a portion of the electrode terminal so that the electrical connection is cut off from the first electrode when the case is deformed while the lead tab is in contact with the case, and the lead tab is at least different. Battery pack, characterized in that formed to be electrically connected to the lead tab of one of the secondary battery.

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