Patent Description:
The present invention relates to an ultrasonic welding device and method for the secondary battery, and more particularly, to an ultrasonic welding device and welding method for the secondary battery, see claims <NUM> and <NUM>.

In general, secondary batteries refer to chargeable and dischargeable batteries, unlike primary batteries that are not chargeable. Such a secondary battery is being widely used in the high-tech electronic fields such as mobile phones, notebook computers, and camcorders.

The secondary batteries are classified into a can type secondary battery, in which an electrode assembly is embedded in a metal can, and a pouch type secondary battery in which an electrode assembly is embedded in a pouch. Also, the pouch type secondary battery comprises an electrode assembly, an electrode lead coupled to an electrode tab of the electrode assembly, and a pouch accommodating the electrode assembly in a state in which a front end of the electrode lead is drawn out.

The electrode tab and the electrode lead of the electrode assembly are coupled through welding. Here, an ultrasonic welding device is used.

The ultrasonic welding device comprises an anvil on which an overlapping surface of the electrode tab and the electrode lead is disposed, and a horn that applies ultrasonic waves to the overlapping surface, which is disposed on the anvil, to weld the overlapping surface.

However, in the ultrasonic welding device has a problem in which, when the anvil and the horn are not disposed horizontally with respect to the overlapping surface, the entire overlapping surface is not uniformly welded to cause welding defects.

In more detail, in the ultrasonic welding device according to the related art, when the anvil and the horn are not disposed horizontally with respect to the overlapping surface, welding energy may not be uniformly transmitted to the entire overlapping surface to cause the welding defects.

<CIT> (describing the preamble of claims <NUM> and <NUM>) relates to an ultrasonic processing apparatus that performs processing such as welding and cutting of a workpiece by ultrasonic waves. <CIT> relates to an apparatus and method for setting the horn parallelism of an ultrasonic welder, more specifically to a horn on an anvil basis by a setting block when checking the deviation of parallelism due to mechanical change during operation or replacement due to wear of the horn and anvil. <CIT> relates to a measurement device for determining the parallelity of two mutually opposing welding surfaces of a material processing device and to a method for aligning the surface of a horn with a surface of an anvil.

An object of the present invention for solving the above problems is provide a secondary battery, in which horizontal levels of an anvil and a horn is adjusted to be disposed horizontally with respect to overlapping surface of an electrode tab and an electrode lead to uniformly (equally) transmit welding energy to the entire overlapping surface of the electrode tab and the electrode lead, thereby uniformly welding the entire overlapping surface, resulting in improving welding quality, and an ultrasonic welding device and welding method for the secondary battery.

An ultrasonic welding device according to the present invention for achieving the above object is defined in claim <NUM>, and comprises: an anvil provided so that an overlapping surface of an electrode tab and an electrode lead, which are provided in an electrode assembly, are disposed thereon; a horn configured to weld the overlapping surface disposed on the anvil; and an inspection member configured to inspect a horizontal level of an opposing member with respect to the overlapping surface, based on an overlapping surface horizontal value that is a horizontal value of the overlapping surface with respect to a predetermined reference surface and an opposing horizontal value that is a horizontal value of the opposing member, which is one of a welding part of the horn facing the overlapping surface and a disposing part of the anvil, on which the overlapping surface is disposed, with respect to the predetermined reference surface.

When the horizontal level is determined as being within a normal range by the inspection member, the horn may be provided to apply ultrasonic waves to the overlapping surface while supporting the welding part of the horn on the overlapping surface.

The ultrasonic welding device further comprises: an overlapping surface measuring member configured to measure an overlapping surface horizontal value of the overlapping surface with respect to the predetermined reference surface; and an opposing measuring member configured to measure an opposing horizontal value that is a horizontal value of the opposing member, which is one of the welding part of the horn facing the overlapping surface and the disposing part of the anvil, on which the overlapping surface is disposed, with respect to the reference surface.

The ultrasonic welding device further comprises an angle adjusting member configured to adjust an angle of the opposing member by a difference value between the overlapping surface horizontal value and the opposing horizontal value.

The angle adjusting member is configured to adjust the angle of the opposing member by the difference value between the overlapping surface horizontal value and the opposing horizontal value when the inspection member determines that the horizontal level is out of the predetermined normal range.

The overlapping surface horizontal value may comprise an inclination angle of the overlapping surface in a full-length direction and an inclination angle of the overlapping surface in a full-width direction in a state in which the predetermined reference surface is set to an angle of <NUM>°, the opposing horizontal value may comprise an inclination angle of the opposing member in a full-length direction and an inclination angle of the opposing member in a full-width direction in a state in which the predetermined reference surface is set to the angle of <NUM>°, and the inspection member may be provided to compare the inclination angle of the overlapping surface in the full-length direction to the inclination angle of the opposing member in the full-length direction and compare the inclination angle of the overlapping surface in the full-width direction to the inclination angle of the opposing member in the full-width direction.

The predetermined normal range is set to an angle of <NUM>° or less.

An ultrasonic welding method for a secondary battery according to the present invention is defined in claim <NUM>, and comprises: a process (a) of disposing an overlapping surface of an electrode tab and an electrode lead, which are provided in an electrode assembly, on an anvil; a process (b) of a horn for welding the overlapping surface disposed on the anvil; and a process (c) of inspecting a horizontal level of an opposing member with respect to the overlapping surface, based on an overlapping surface horizontal value that is a horizontal value of the overlapping surface with respect to a predetermined reference surface and an opposing horizontal value that is a horizontal value of the opposing member, which is one of a welding part of the horn facing the overlapping surface and a disposing part of the anvil, on which the overlapping surface is disposed, with respect to the predetermined reference surface.

The process (c) may further comprise a process of applying ultrasonic waves in a state of supporting the welding part of the horn on the overlapping surface when the horizontal level is determined as being normal range.

The process (c) further comprises a process of adjusting the angle of the opposing member by a difference value between the overlapping surface horizontal value and the opposing horizontal value when the inspection member determines that the horizontal level is out of the predetermined normal range.

The process (a) further comprises a process of measuring the overlapping surface horizontal value that is a horizontal value of the overlapping surface with respect to the predetermined reference surface.

The process (b) further comprises a process of measuring an opposing horizontal value that is a horizontal value of the opposing member, which is one of the welding part of the horn facing the overlapping surface and the disposing part of the anvil, on which the overlapping surface is disposed, with respect to the reference surface.

The ultrasonic welding device for the secondary battery of the present invention comprises the inspection member that inspects the horizontal levels of the anvil and the horn with respect to the overlapping surface of the electrode tab and the electrode lead. That is, the inspection member may inspect the horizontal level of the opposing member with respect to the overlapping surface, based on the overlapping surface horizontal value, which is the horizontal value of the overlapping surface with respect to the predetermined reference surface, and the opposing horizontal value, which is the horizontal value with respect to the reference surface of the opposing member that is one of the welding part of the horn facing the overlapping surface and the disposing part of the anvil on which the overlapping surface is disposed. Therefore, it may be inspected whether the anvil and the horn uniformly press the entire overlapping surface, and as a result, it may be inspected whether the defects occur.

In addition, the ultrasonic welding device for the secondary battery according to the present invention may comprises an angle adjusting member for correcting the angles of the anvil and the horn with respect to the overlapping surface. That is, the angle adjusting member may be configured to adjust the angle of the opposing member by the difference value between the overlapping surface horizontal value and the opposing horizontal value when the inspection member determines that the horizontal level is out of the predetermined normal range. Therefore, the anvil and the horn may uniformly press the entire overlapping surface, and as a result, the bonding force of the entire overlapping surface may be uniform to prevent the defects from occurring.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in such a manner that the technical idea of the present invention may easily be carried out by a person with ordinary skill in the art to which the invention pertains. In the drawings, anything unnecessary for describing the present invention will be omitted for clarity, and also like reference numerals in the drawings denote like elements.

As illustrated in <FIG>, a secondary battery <NUM> comprises an electrode assembly <NUM> in which an electrode tab <NUM> is provided, an electrode lead <NUM> coupled to the electrode tab <NUM>, and a pouch <NUM> accommodating the electrode assembly <NUM> in a state in which a front end of the electrode lead <NUM> is withdrawn to the outside.

Here, the electrode tab <NUM> and the electrode lead <NUM> are disposed to partially overlap each other, and then, the overlapping portion of the electrode tab <NUM> and the electrode lead <NUM> is ultrasonic-welded to bond the electrode tab <NUM> to the electrode lead <NUM>. That is, an overlapping surface <NUM> coupled by the ultrasonic welding is provided at the overlapping portion of the electrode tab and the electrode lead. Here, the ultrasonic welding device according to the first embodiment of the present invention for the second battery is used.

Particularly, since the overlapping surface <NUM> may be ultrasonic-welded through the ultrasonic welding device for the secondary battery, overall bonding strength in a full-length direction (a left and right direction when viewed in <FIG>) of the overlapping surface <NUM> and the overall bonding force in a full-width direction (a front and rear direction when viewed in <FIG>) may be uniformly (equally) provided to improve welding quality.

Hereinafter, an ultrasonic welding device for a secondary battery according to the first embodiment of the present invention will be described in detail.

As illustrated in <FIG>, an ultrasonic welding device <NUM> for a secondary battery according to a first embodiment of the present invention comprises an anvil <NUM> on which an overlapping surface <NUM> of an electrode tab <NUM> and an electrode lead <NUM>, which are provided in the electrode assembly <NUM>, is disposed, and a horn <NUM> provided to weld the overlapping surface <NUM> disposed on the anvil <NUM>.

That is, in the ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention, in a state in which the anvil <NUM> and the horn <NUM> press-fit the overlapping surface <NUM> of the electrode tab <NUM> and the electrode lead <NUM>, the overlapping surface <NUM> may be ultrasonic-welded through the horn <NUM> to connect and couple the electrode tab <NUM> to the electrode lead <NUM>.

In the ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention, when a welding part <NUM> of the horn <NUM> or a disposing part <NUM> of the anvil, on which the overlapping surface is disposed, has a horizontal level different from that of the overlapping surface <NUM>, the entire overlapping surface <NUM> may not be uniformly press-fitted through the anvil <NUM> and the horn <NUM>, and thus, a difference in welding energy applied to the entire overlapping surface <NUM> may occur to cause welding defects.

In order to solve the above problems, the ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention comprises an inspection member that inspects the horizontal level of the disposing part <NUM> of the anvil or the welding part <NUM> of the horn <NUM> with respect to the overlapping surface <NUM>. The inspection member <NUM> may inspect whether the entire overlapping surface <NUM> is uniformly press-fitted through the anvil <NUM> and the horn <NUM>, to inspect whether the welding defects occur.

That is, the inspection member <NUM> may inspect the horizontal level of an opposing member with respect to the overlapping surface <NUM>, based on an overlapping surface horizontal value, which is a horizontal value of the overlapping surface <NUM> with respect to a predetermined reference surface <NUM>, and an opposing horizontal value, which is a horizontal value with respect to a reference surface of an opposing member that is one of the welding part <NUM> of the horn <NUM> and the disposing part <NUM> of the anvil on which the overlapping surface is disposed.

Here, when it is determined that the horizontal level is within a predetermined normal range by the inspection member <NUM>, the horn <NUM> is provided to apply ultrasonic waves in a state in which the welding part <NUM> of the horn <NUM> is supported on the overlapping surface <NUM>, and thus, welding energy applied to the entire overlapping surface <NUM> may be uniform to improve welding quality due to the uniform welding on the entire overlapping surface.

Thus, the ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention may comprise the inspection member to detect the horizontal level of the disposing part <NUM> of the anvil <NUM> or the welding part <NUM> of the horn <NUM> with respect to the overlapping surface <NUM>, thereby inspecting whether the entire overlapping surface <NUM> is uniformly press-fitted, and as a result, inspecting whether welding defects occur.

The ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention comprises an overlapping surface measuring member <NUM>, which measures an overlapping surface horizontal value that is a horizontal value of the overlapping surface <NUM> with respect to the predetermined reference surface <NUM>, and an opposing measuring member, which measures an opposing horizontal value that is a horizontal value of the opposing member, which is one of the welding part <NUM> of the horn <NUM>, which faces the overlapping surface <NUM>, and the disposing part <NUM> of the anvil <NUM> on which the overlapping surface <NUM> is disposed, with respect to the reference surface <NUM>.

The overlapping surface measuring member <NUM> is provided close to the overlapping surface <NUM> of the electrode tab <NUM> and the electrode lead <NUM> to measure the horizontal value of the overlapping surface <NUM> based on the reference surface <NUM>. That is, the overlapping surface measuring member <NUM> calculates the overlapping surface horizontal value of how many degrees the overlapping surface <NUM> has an inclination angle with respect to the reference surface <NUM>.

On the other hand, the overlapping surface measuring member <NUM> is provided with at least three places on the overlapping surface <NUM>, and thus, the overlapping surface measuring member <NUM> may measure horizontal values at the three or more places of the overlapping surface <NUM> to calculate the overlapping surface horizontal value as an average of the measured horizontal values as the three or more places.

The horizontal value of the overlapping surface comprises an inclination angle A1° of the overlapping surface <NUM> in the full-length direction and an inclination angle A2° of the overlapping surface <NUM> in the full-width direction in a state in which the reference surface is set to an angle of <NUM>°. That is, the overlapping surface measuring member <NUM> measures the overlapping surface horizontal value comprising the inclination angle A1° of the overlapping surface in the full-length direction and the inclination angle A2° of the overlapping surface in the full-width direction with respect to the reference surface <NUM>.

The opposing measuring member measures an opposing horizontal value that is a horizontal value of the opposing member, which is one of the welding part <NUM> of the horn <NUM> facing the overlapping surface <NUM> and the disposing part <NUM> of the anvil <NUM> on which the overlapping surface <NUM> is disposed, with respect to the reference surface <NUM>. That is, the opposing measuring member measures the opposing horizontal value to determine how many degrees the opposing member has an inclination angle with respect to the overlapping surface.

The opposing horizontal value comprises an inclination angle of the opposing member in the full-length direction and an inclination angle of the opposing member in the full-width direction in a state in which the reference surface or the overlapping surface is set to an angle of <NUM>°. Accordingly, the inspection member is provided to compare the inclination angle of the overlapping surface in the full-length direction to the inclination angle of the opposing member in the full-length direction and is provided to compare the inclination angle of the overlapping surface in the full-width direction to the inclination angle of the opposing member in the full-width direction.

For example, the opposing member comprises a horn measuring member <NUM> and an anvil measuring member <NUM>.

The horn measuring member <NUM> measures a horizontal value of the welding part of the horn <NUM> facing the overlapping surface <NUM> with respect to the reference surface <NUM>. The horizontal value of the welding part of the horn comprises an inclination angle B1° of the horn <NUM> in the full-length direction and an inclination angle B2° of the horn <NUM> in the full-width direction in a state in which the reference surface <NUM> is set to an angle of <NUM>°. That is, the horn measuring member <NUM> measures a horizontal value of the welding part of the horn, which comprises the inclination angle B1° of the horn <NUM> in the full-length direction and an inclination angle B2° of the horn <NUM> in the full-width direction with respect to the reference surface <NUM>.

That is, the inspection member <NUM> compares the horizontal value of the overlapping surface, which is measured by the overlapping surface measuring member <NUM>, to the horizontal value of the welding part, which is measured by the horn measuring member <NUM>. Then, when it is determined that the difference value is within a normal range, it is determined as being normal, and on the other hand, when it is determined that the difference value is out of the normal range, it is determined as being defective.

For example, the inspection member <NUM> compares the inclination angle A1° of the overlapping surface <NUM> in the full-length direction to the inclination angle B1° of the horn <NUM> in the full-width direction to calculate a difference value of the horn in the full-length direction and also compares the inclination angle A2° of the overlapping surface <NUM> in the full-width direction to the inclination angle B2° of the horn <NUM> in the full-width direction to calculate a difference value of the horn in the full-width direction.

Therefore, the inspection member <NUM> determines that both the difference value in the full-length direction of the horn and the difference value in the full-width direction of the horn are within the normal range, and if any one is determined as the normal range, it is determined as being defective.

The anvil measuring member <NUM> is provided in the anvil <NUM> to measure the horizontal value of the disposing part <NUM> of the anvil <NUM> based on the reference surface <NUM>.

As an example, the horizontal value of the arrangement comprises an inclination angle C1° of the anvil <NUM> in the full-length direction and an inclination angle C2° of the anvil <NUM> in the full-width direction in a state in which the reference surface <NUM> is set to an angle of <NUM>°. That is, the anvil measuring member <NUM> measures the inclination angle C1° of the anvil <NUM> in the full-length direction and the inclination angle C2° of the anvil <NUM> in the full-width direction with respect to the reference surface <NUM>.

As described above, when the horizontal value of the disposing part is measured by the anvil measuring member, the inspection member <NUM> compares the horizontal value of the disposing part of the anvil <NUM>, which is measured by the anvil measuring member <NUM>, to the horizontal value of the overlapping surface, which is measured by the overlapping surface measuring member <NUM>. Then, when it is determined that the difference value is within a normal range, it is determined as being normal, and on the other hand, when it is determined that the difference value is out of the normal range, it is determined as being defective.

Here, the inspection member <NUM> compares the inclination angle A1° of the overlapping surface <NUM> in the full-length direction to the inclination angle C1° of the anvil <NUM> in the full-width direction to calculate a difference value of the anvil in the full-length direction and also compares the inclination angle A2° of the overlapping surface <NUM> in the full-width direction to the inclination angle C2° of the anvil <NUM> in the full-width direction to calculate a difference value of the anvil in the full-width direction.

Therefore, the inspection member <NUM> determines that both the difference value in the full-length direction of the anvil and the difference value in the full-width direction of the anvil are within the normal range, and if any one is determined as being out of the normal range, it is determined as being defective.

The ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention, which has the above-described configuration, may comprise the overlapping surface measuring member <NUM> and the opposing measuring member to accurately confirm a horizontal level of each of the horn <NUM> and the anvil with respect to the overlapping surface, thereby accurately confirming possibility of occurrence of welding defects.

Here, the reference surface <NUM> may be the ground or a support surface of a worktable on which the ultrasonic welding device is installed.

The ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention further comprises an angle adjusting member that adjusts an angle of the opposing member by a difference value between the overlapping surface horizontal value and the opposing horizontal value when the horizontal level is determined as being defective.

That is, the angle adjusting member may adjust an angle of the opposing member by a difference value between the overlapping surface horizontal value and the opposing horizontal value when the horizontal level is determined as being out of a predetermined normal range through the inspection member <NUM>. Thus, the horizontal level of the opposing member with respect to the overlapping surface <NUM> may be adjusted to be disposed within the normal range.

For example, the angle adjusting member comprises a horn angle adjusting member <NUM> and an anvil angle adjusting member <NUM>.

When determined as being defective by the inspection member <NUM>, the horn angle adjusting member <NUM> allows the horn <NUM> to rotate in a left and right or a front and rear direction by a difference value obtained by subtracting the horizontal value of the overlapping surface and the horizontal value of the welding part of the horn <NUM>. Thus, the horizontal value of the overlapping surface and the horizontal value of the welding part of the horn <NUM> may be disposed to match each other with respect to the reference surface.

When determined as being defective by the inspection member <NUM>, the anvil angle adjusting member <NUM> allows the anvil <NUM> to rotate in the left and right or the front and rear direction by a difference value obtained by subtracting the horizontal value of the overlapping surface and the horizontal value of the disposing part of the anvil <NUM>, thereby adjusting the horizontal level of the disposing part of the anvil <NUM>. Thus, the horizontal value of the overlapping surface and the horizontal value of the disposing part may be disposed to match each other with respect to the reference surface.

The normal range may be less than <NUM>°, preferably less than <NUM>°.

Therefore, the ultrasonic welding device <NUM> for the secondary battery according to the first embodiment of the present invention may comprise the angle adjusting member so that the horizontal level of the opposing member with respect to the overlapping surface <NUM> is adjusted to be disposed within the normal range, thereby welding the entire overlapping surface with uniform welding energy through the anvil and the horn in the state of press-fitting the entire overlapping surface.

Hereinafter, a welding method using the ultrasonic welding device for the secondary battery according to the first embodiment of the present invention will be described.

As illustrated in <FIG>, an ultrasonic welding method for the secondary battery according to a first embodiment of the present invention is performed to weld an electrode tab <NUM> and an electrode lead <NUM>, which are provided in an electrode assembly <NUM> and comprises a process (a) of disposing an overlapping surface on anvil, a process (b) of disposing a horn for welding the overlapping surface, a process (c) of inspecting a horizontal level; and a welding process.

In the process (a), the overlapping surface <NUM> of the electrode tab <NUM> and the electrode lead <NUM>, which are provided in the electrode assembly <NUM>, is disposed on the anvil <NUM>.

Here, the process (a) further comprises a process of measuring a horizontal value of the overlapping surface, which is a horizontal value of the overlapping surface <NUM> with respect to a predetermined reference surface <NUM>. Here, an overlapping surface measuring member <NUM> is used.

That is, the overlapping surface measuring member <NUM> measure the horizontal value of the overlapping surface <NUM> based on the reference surface <NUM>. Here, the overlapping surface measuring member <NUM> measures an inclination angle of the overlapping surface <NUM> in a full-length direction and an inclination angle of the overlapping surface <NUM> in a full-width direction based on the horizontal value of the overlapping surface.

In the process (b), a horn <NUM> for welding the overlapping surface <NUM> disposed on the anvil <NUM> is disposed.

Here, in the process (b) further comprises a process of measuring an opposing horizontal value that is a horizontal value of an opposing member, which is one of a welding part <NUM> of the horn <NUM> facing the overlapping surface <NUM> and a disposing part <NUM> of the anvil <NUM> on which the overlapping surface <NUM> is disposed, with respect to the reference surface. Here, an opposing measuring member is used, and the opposing measuring member comprises an anvil measuring member <NUM> and a horn measuring member <NUM>.

The anvil measuring member <NUM> measures a horizontal value of the disposing part of the anvil <NUM>, on which the overlapping surface is disposed, based on a reference surface. The horn measuring member <NUM> measures a horizontal value of the welding part of the horn facing the overlapping surface <NUM>, based on the reference surface.

In the process (c), the horizontal level of the opposing member with respect to the overlapping surface <NUM> is inspected based on the overlapping surface horizontal value, which is the horizontal value of the overlapping surface <NUM> with respect to the predetermined reference surface <NUM>, and the opposing horizontal value that is the horizontal value of the opposing member, which is one of the welding part <NUM> of the horn <NUM> and the disposing part <NUM> of the anvil, on which the overlapping surface is disposed, with respect to a reference surface. Here, an inspection member <NUM> is used.

The inspection member <NUM> compares the horizontal value of the disposing part to the horizontal value of the overlapping surface to determine whether the difference value is within the normal range. As a result, when it is determined that the difference value is out of the normal range, it is determined as being defective, whereas, when it is determined that that difference value is within the normal range, it is determined as being normal. That is, the inspection member <NUM> may confirm a difference in pressing force applied to the entire overlapping surface through the overlapping surface horizontal value and the disposing part horizontal value, and thus, it may be confirmed in advance that welding defects occur on the overlapping surface <NUM>.

In addition, the inspection member <NUM> compares the overlapping surface horizontal value to the welding part horizontal value to determine whether the difference value is within the normal range. As a result, when it is determined that the difference value is out of the normal range, it is determined as being defective, whereas, when it is determined that that difference value is within the normal range, it is determined as being normal. That is, the inspection member <NUM> may confirm a difference in pressing force applied to the entire overlapping surface <NUM> through the overlapping surface horizontal value and the welding part horizontal value, and thus, it may be confirmed in advance that welding defects occur on the overlapping surface <NUM>.

Here, the process (c) further comprises a process of applying ultrasonic waves to weld the overlapping surface <NUM> while supporting the welding part <NUM> of the horn <NUM> on the overlapping surface <NUM> when the horizontal level is determined as being within a predetermined normal range.

The predetermined normal range may be less than <NUM>°, preferably less than <NUM>°.

The process (c) further comprises a process of adjusting an angle of the opposing member by a difference value between the overlapping surface horizontal value and the opposing horizontal value when the horizontal level is determined as being within the predetermined normal range. Here, the angle adjusting member is used, and the angle adjusting member comprises a horn angle adjusting member <NUM> and an anvil angle adjusting member <NUM>.

That is, the horn angle adjusting member <NUM> is provided to adjust the horizontal level of the horn and thus adjusts an angle of the welding part of the horn <NUM> by the difference between the overlapping surface horizontal value and the welding part horizontal value to match the overlapping surface horizontal value with the welding part horizontal value, thereby uniformly applying the entire overlapping surface or uniformly applying the ultrasonic waves to the entire overlapping surface so as to prevent welding defects from occurring.

The anvil angle adjusting member <NUM> is provided to adjust the horizontal level of the anvil and thus adjusts an angle of the disposing surface of the anvil by the difference value between the disposing part horizontal value of the anvil and the overlapping surface horizontal value. Thus, the disposing part horizontal value of the anvil may be matched with the overlapping surface horizontal value, thereby preventing the welding defects from occurring.

Therefore, in the ultrasonic welding method for the secondary battery according to the first embodiment of the present invention, the entire overlapping surface of the electrode tab and the electrode lead may be uniformly welded, and as a result, the welding quality may be improved.

An electrode tab and an electrode lead are welded using the ultrasonic device <NUM> for the secondary battery according to the first embodiment of the present invention.

In Preparation Example <NUM>, when a horizontal level between an anvil <NUM> and a horn <NUM> is <NUM>°, an overlapping surface of the electrode tabs and the electrode leads is welded, and then, the welded overlapping surface is photographed. Then, a picture as shown in <FIG> may be obtained. Here, a unit area (mm<NUM>) of the welded overlapping surface has a length of <NUM> and a width of <NUM>.

In Preparation Example <NUM>, when a difference in horizontal level between the anvil <NUM> and the horn <NUM> is <NUM>°, the overlapping surface of the electrode tab and the electrode lead is welded, and then, the welded overlapping surface is photographed. Then, a picture as shown in <FIG> may be obtained. Here, a unit area (mm<NUM>) of the welded overlapping surface has a length of <NUM> and a width of <NUM>.

Here, the electrode tab comprises a negative electrode tab and a positive electrode tab, and the electrode lead comprises a negative electrode lead and a positive electrode lead. That is, the welded state of the negative electrode tab and the negative electrode lead and the welded state of the positive electrode tab and the positive electrode lead are tested respectively.

Referring to <FIG> in Preparation Example <NUM>, it is seen that the entire overlapping surface of the electrode tab and the electrode lead is uniformly welded.

Referring to <FIG>, in Preparation Example <NUM>, it is seen that welding defects occur at a portion of a right side of the entire overlapping surface of the electrode tab and the electrode lead. That is, it is confirmed that the welding defects occur in a spaced portion between the anvil and the horn.

Referring to <FIG>, in Preparation Example <NUM>, it is seen that welding defects occur at about half of the entire overlapping surface of the electrode tab and the electrode lead. That is, it is seen that the welding defects occur as about half of the anvil and the horn is not pressed.

Therefore, in the ultrasonic device <NUM> for the secondary battery according to the first embodiment of the present invention, as in Preparation Example <NUM>, when welding the overlapping surfaces of the electrode tab and the electrode lead, the horizontal levels of the anvil and the horn are adjusted to be the same to uniformly weld the entire overlapping surface of the electrode tab and the electrode lead, thereby improving the welding quality.

As the result of measuring the tensile strength of the overlapping surface of the negative electrode tab and the negative electrode lead, which are welded in Preparation Examples <NUM> to <NUM>, a graph as shown in <FIG> may be obtained.

As the result of measuring the tensile strength of the overlapping surface of the positive electrode tab and the positive electrode lead, which are welded in Preparation Examples <NUM> to <NUM>, a graph as shown in <FIG> may be obtained.

Here, managed tensile strength of the negative electrode is set to <NUM> N (<NUM> kgf). Also, managed tensile strength of the positive electrode is set to <NUM> N (60kgf). In addition, a unit area (mm<NUM>) of each of the overlapping surface of the welded negative electrode tab and negative electrode lead and a unit area (mm<NUM>) of the overlapping surface of the welded positive electrode tab and positive electrode lead is provided with a length of <NUM>, a width of <NUM>, and a thickness of <NUM>.

As the test result of the overlapping surface of the welded negative electrode tab and negative electrode lead, referring to <FIG>, in Preparation Example <NUM>, it is confirmed as normal welding because the measured tensile strength is greater than the managed tensile strength. In addition, in Preparation Example <NUM>, it is confirmed as normal welding because the measured tensile strength corresponds to the managed tensile strength, and in Preparation Example <NUM>, it is confirmed as defective welding because the measured tensile strength is less than the managed tensile strength.

As the test result of the overlapping surface of the welded positive electrode tab and positive electrode lead, referring to <FIG>, in Preparation Example <NUM>, it is confirmed as normal welding because the measured tensile strength is measured to be greater than the managed tensile strength. In addition, in Preparation Example <NUM>, it is confirmed as normal welding because the measured tensile strength corresponds to the managed tensile strength, and in Preparation Example <NUM>, it is confirmed as defective welding because the measured tensile strength is measured to be less than the managed tensile strength.

Claim 1:
An ultrasonic welding device (<NUM>) for a secondary battery comprising:
a predetermined reference surface (<NUM>);
an anvil (<NUM>) provided so that an overlapping surface (<NUM>) of an electrode tab (<NUM>) and an electrode lead (<NUM>), which are provided in an electrode assembly (<NUM>), are disposed thereon;
a horn (<NUM>) configured to weld the overlapping surface (<NUM>) disposed on the anvil (<NUM>);
an overlapping surface measuring member (<NUM>) configured to measure an overlapping surface horizontal value (A1, A2) of the overlapping surface (<NUM>) with respect to the predetermined reference surface (<NUM>), wherein the overlapping surface horizontal value (A1, A2) is a horizontal value of the overlapping surface (<NUM>) with respect to the predetermined reference surface (<NUM>), and
an opposing measuring member (<NUM>) configured to measure an opposing horizontal value (B1, B2; C1, C2), wherein the opposing horizontal value (B1, B2; C1, C2) is a horizontal value of the opposing member (<NUM>; <NUM>) with respect to the predetermined reference surface (<NUM>),
wherein the opposing member (<NUM>; <NUM>) is one of a welding part (<NUM>) of the horn (<NUM>) facing the overlapping surface (<NUM>) and a disposing part (<NUM>) of the anvil (<NUM>), on which the overlapping surface (<NUM>) is disposed; and
characterised in that the ultrasonic welding device (<NUM>) comprises:
an inspection member (<NUM>) configured to inspect a horizontal level of an opposing member (<NUM>; <NUM>) with respect to the overlapping surface (<NUM>) based on the overlapping surface horizontal value (A1, A2) and the opposing horizontal value (B1, B2; C1, C2),
wherein the inspection member (<NUM>) is further configured to compare the horizontal value of the overlapping surface (<NUM>) to the horizontal value of the opposing member (<NUM>, <NUM>), and to determine that the difference value is within a normal range or that the difference value is out of the normal range and therefore being defective,
wherein the predetermined normal range is set to an angle of <NUM>° or less, and
in that the ultrasonic welding device (<NUM>) further comprises: an angle adjusting member (<NUM>) configured to adjust the angle of the opposing member (<NUM>; <NUM>) by the difference value between the overlapping surface horizontal value (A1, A2) and the opposing horizontal value (B1, B2; C1, C2) when the inspection member (<NUM>) determines that the horizontal level is out of the predetermined normal range.