RECHARGEABLE BATTERY MODULE

A rechargeable battery module is provided including a plurality of battery cells arranged in a first row and a second row parallel to the first row; a holder for receiving the plurality of battery cells; and a tab member disposed on the holder, positioned relative to the first and the second rows and welded to respective electrode terminals of plurality of the battery cells, wherein the tab member includes a body portion disposed between the first row and the second row, a first neck portion connected to the body portion, disposed along the first row, and connected to electrode terminals of one or more battery cells arranged in the first row with a first tab, and a second neck portion connected to the body portion, disposed along the second row, and connected to electrode terminals of one or more battery cells arranged in the second row with a second tab.

CROSS-REFERENCE TO RELATED APPLICATIONS

This present application claims priority to and the benefit under 35 U.S.C. § 119(a)-(d) of Korean Patent Application No. 10-2023-0117102, filed on Sep. 4, 2023, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.

FIELD

The present disclosure relates to a rechargeable battery module. More particularly, the present disclosure relates to a rechargeable battery module for minimizing a voltage difference between cells.

BACKGROUND

A rechargeable battery is a battery that is capable of being repeatedly charged and discharged, unlike a primary cell. Small rechargeable batteries may be used for small portable electronic devices such as mobile phones, laptop computers, or camcorders. Large capacity and high density rechargeable batteries may be used to store motor driving power or energy for hybrid vehicles and/or electric vehicles.

SUMMARY

The present disclosure provides a rechargeable battery module for minimizing a voltage difference between battery cells sharing tab members.

An embodiment of the present disclosure provides a rechargeable battery module comprising: a plurality of battery cells disposed in a first row and a second row parallel to the first row; a holder for receiving the plurality of battery cells; and a tab member disposed on the holder, positioned relative to the first row and the second row and welded to respective electrode terminals of the plurality of battery cells, wherein the tab member comprises a body portion disposed between the first row and the second row, a first neck portion connected to the body portion, disposed along the first row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the first row with a first tab, and a second neck portion connected to the body portion, disposed along the second row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the second row with a second tab.

The first tab of the first neck portion may have a pair of electrically connected first tabs, and each tab of the pair of first tabs may be welded to respective electrode terminals of two battery cells of the plurality of battery cells, the two battery cells being disposed in the first row and may be electrically connected to each other.

The first neck portion may be disposed around the two battery cells disposed in the first row and may be disposed between the two battery cells in the first row, and the pair of electrically connected first tabs may be disposed around the two battery cells disposed in the first row.

The second tab of the second neck portion may comprise a pair of electrically connected second tabs, and each tab of the pair of electrically connected second tabs may be welded to electrode terminals of the two battery cells which are disposed in the second row and may be electrically connected to each other.

The second neck portion may be disposed around the two battery cells disposed in the second row and may be disposed between the two battery cells in the second row, and the pair of electrically connected second tabs are disposed around the two battery cells disposed in the second row direction.

Each of the plurality of battery cells may be a cylindrical rechargeable battery, an axial-direction center of the one or more battery cells arranged in the first row and an axial-direction center of the one or more battery cells arranged in the second row may be offset from each other in a direction along the second row such that a line passing through the axial-direction centers of a battery cell disposed at an end of the first row and a battery cell disposed at an end of the second row has angle relative to a direction in which the second row is disposed that is other than 90 degrees.

The tab member may include a bent portion being bent downwards relative to a plane of the body portion of the tab member and along a direction parallel to the line passing through the axial direction centers of the battery cell disposed at the end of the first row and the battery cell disposed at the end of the second row, the bent portion may be connected to an end of the body portion of the tab member, and formed to have a cross-section that is downward convex relative to the plane of the body portion.

The bent portion may have a curvature radius, and an upper-end bending start point of the curvature radius may be disposed on a diagonal upper portion of a round portion formed on a respective end of a battery cell of the plurality of batter cells in the axial direction.

The bent portion may have a curvature radius, and an upper-end bending start point of the curvature radius may be disposed on an upper portion of a round portion formed on a respective end of a battery cell of the plurality of battery cells in the axial direction.

The bent portion may further include a lateral convex surface that is convex toward a lateral surface of a battery cell of the plurality of battery cells.

The bent portion may be formed to have a curved cross-section (U) that is downward convex on a lateral surface of a battery cell of the plurality of battery cells.

The bent portion may be formed to have an angled cross-section (V) that is downward convex on a lateral surface of a battery cell of the plurality of battery cells.

A connection structure of the first tab may include an eleventh connection welded to the electrode terminals of the one or more battery cells arranged in the first row in two pieces, bent, and extending in a height direction, a twelfth connection extending in a direction that is orthogonal to the first row, and a thirteenth connection extending along a direction of the first row to be connected to the first neck portion.

A connection structure of the second tab may include a twenty first connection welded to the electrode terminals of the one or more battery cells arranged in the second row, bent, and extending in a height direction, a twenty second connection extending in a direction that is orthogonal to the second row, and a twenty third connection extending along a direction of the second row to be connected to the second neck portion.

An embodiment of the present disclosure provides a method of manufacturing a rechargeable battery module. The method may comprise providing holder for receiving a plurality of battery cells; arranging the plurality of battery cells in the holder in a first row and a second row parallel to the first row; installing a tab member on the holder, positioned relative to the first row and the second row wherein installing the tab member comprises welding the tab member to respective electrode terminals of the plurality of battery cells, and wherein the tab member comprises: a body portion disposed between the first row and the second row, a first neck portion connected to the body portion, disposed along the first row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the first row with a first tab, and a second neck portion connected to the body portion, disposed along the second row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the second row with a second tab.

A connection structure of the first tab may include an eleventh connection welded to the electrode terminals of the one or more battery cells arranged in the first row in two pieces, bent, and extending in a height direction, a twelfth connection extending in a direction that is orthogonal to the first row, and a thirteenth connection extending along a direction of the first row to be connected to the first neck portion.

A connection structure of the second tab may include a twenty first connection welded to the electrode terminals of the one or more battery cells arranged in the second row, bent, and extending in a height direction, a twenty second connection extending in a direction that is orthogonal to the second row, and a twenty third connection extending along a direction of the second row to be connected to the second neck portion.

An embodiment of the present disclosure provides a tab member for use in a rechargeable battery module and configured to be disposed on a holder of the rechargeable battery module and welded to respective electrode terminals of a plurality of battery cells of the rechargeable battery module. The tab member may comprise a body portion configured to be disposed between first and second rows of the battery cells of the plurality of battery cells; a first neck portion connected to the body portion, configured to be disposed along the first row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the first row with a first tab, and a second neck portion connected to the body portion, configured to be disposed along the second row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the second row with a second tab.

A connection structure of the first tab may include an eleventh connection welded to the electrode terminals of the one or more battery cells arranged in the first row in two pieces, bent, and extending in a height direction, a twelfth connection extending in a direction that is orthogonal to the first row, and a thirteenth connection extending along a direction of the first row to be connected to the first neck portion.

A connection structure of the second tab may include a twenty first connection welded to the electrode terminals of the one or more battery cells arranged in the second row, bent, and extending in a height direction, a twenty second connection extending in a direction that is orthogonal to the second row, and a twenty third connection extending along a direction of the second row to be connected to the second neck portion.

Regarding the rechargeable battery module according to an embodiment, the tab member may include the body portion, the first and second neck portions, and the first and second tabs to connect the electrode terminals of the battery cells of the first and second rows, thereby sharing the body portion of the tab member. Therefore, the voltage difference between the battery cells may be minimized. Hence, the reduction of the lifespan of the battery cells may be prevented.

DETAILED DESCRIPTION

The rechargeable battery may be used as a rechargeable battery module including a plurality of battery cells connected in series and/or parallel to drive a motor of, for example, a hybrid vehicle requiring relatively high energy density. For example, to implement a relatively high-output rechargeable battery module (e.g., an electric vehicle), the rechargeable battery module may be formed by connecting electrode terminals of the battery cells using a number of battery cells that satisfies a desired electric power amount.

For example, the rechargeable battery module is formed by storing battery cells in a holder and connecting the battery cells in series and/or in parallel with tabs. The rechargeable battery module has a high voltage and current depending on the consumer's usage conditions, so the rechargeable battery module may include tabs that connect the battery cells and a battery management system connected to the tabs.

At this time, the battery cells are connected to one tab so a voltage difference may occur between the battery cells depending on discharge. Voltage differences between the battery cells may deteriorate the lifespan of the battery cells.

FIG.1shows an exploded perspective view of a rechargeable battery module according to a first embodiment of the present disclosure, andFIG.2shows a top plan view of a rechargeable battery module according to the first embodiment of the present disclosure. Referring toFIG.1andFIG.2, the rechargeable battery module1according to a first embodiment may include battery cells10, a holder20for receiving the battery cells10, and a tab member50welded to electrode terminals40of the battery cells10.

Each of the battery cells10may be a cylindrical rechargeable battery, and may include electrode terminals40on respective ends of the cylindrical rechargeable battery in an axial direction. That is, the electrode terminal40of a battery cell may include a positive terminal41and a negative terminal42installed at respective ends of the respective battery cells10in the axial direction.

The holder20may include a bottom holder21and a top holder22. The bottom holder21and the top holder22may form a honey comb structure therein to receive the battery cells10spaced in a first direction (x-axis direction) and a second direction (y-axis direction) crossing the first direction, and may be combined to each other in a third direction (z-axis direction) crossing the second direction and may be firmly fastened by a fastening member23.

In the state ofFIG.1, the bottom holder21may receive lower sides of the battery cells10, and the top holder22may receive upper sides of the battery cells10. The bottom holder21and the top holder22are fastened by the fastening member23.

The bottom holder21and the top holder22may be further combined in a snap-fit structure comprising a protrusion24installed outside the bottom holder21and a coupling part25installed outside the top holder22corresponding to the protrusion24.

FIG.3shows a top plan view of a tab member for connecting four battery cells of the rechargeable battery module ofFIG.2. Referring toFIG.1,FIG.2, andFIG.3, the battery cells10may be received in the holder20and may be arranged in a first row R1and a second row R2in parallel to the first row R1. The first row R1and the second row R2may be set in the second direction and may be spaced from each other in the first direction.

For example, the positive terminal41of a battery cell may be disposed on an upper portion of the rechargeable battery module, and the negative terminal42may be disposed on a lower portion in the first row R1. The positive terminal41may be disposed on a lower portion of the rechargeable battery module and the negative terminal42may be disposed on an upper portion in the second row R2.

An axial-direction center of the battery cells10disposed in the first row R1and an axial-direction center of the battery cells10disposed in the second row R2are offset along a direction of the first and second rows R1, R2. Therefore, the cylindrical battery cells10may be prevented from being adjacent with each other.

That is, relative to the battery cells10disposed in the first row R1, the battery cells10disposed in the second row R2may be shifted in the second direction (y-axis direction). Therefore, a line passing through centers of the two battery cells10disposed at the ends of the first row R1and the second row R2may have an angle (θ) (e.g., other than 90 degrees) from the direction in which the first row R1and the second row R2are disposed.

For example, the tab members50may comprise a nickel material, and the battery cells10may be electrically connected in parallel and/or in series and may be connected to the battery management system (BMS)30. The tab members50may be formed by punching a thin plate material.

For example, the battery management system (BMS)30may be installed on the lateral surfaces of the bottom holder21and the top holder22. The tab members50may respectively have an output end54on one side of the first direction (x-axis direction), and may be electrically connected to the battery management system (BMS)30through the output ends54.

The tab members50may be disposed in a seating groove221of the bottom holder21and the top holder22and may connect the corresponding electrode terminals40. A protruding portion222may be installed on one side of the seating groove221and may engage with a combined hole (H) that corresponds to the tab member50.

Therefore, the seating groove221may set a position of the tab member50, before welding the tab member50to the electrode terminal40, to maintain the position of the tab member50. The protruding portion222may engage with the combined hole (H), when completing the setting of the position of the tab member50, to prevent the tab member50from being separated from the seating groove221.

FIG.4shows a perspective view of a tab member ofFIG.2. Referring toFIG.4, the tab member50may include a body portion51, a first tab521, a second tab522, a first neck portion531, and a second neck portion532.

A connection structure of the first tab521may include an eleventh connection C11configured to be welded to the positive terminal41in two pieces, bent, and extending in the height direction (z-axis direction), a twelfth connection C12extending in a direction that is orthogonal to the first row R1, and a thirteenth connection C13extending in the direction of the first row R1to be connected to the first neck portion531.

A connection structure of the second tab522may include a twenty first connection C21configured to be welded on the negative terminal42in two pieces, bent, and extending in the height direction (z-axis direction), a twenty second connection C22extending in a direction that is orthogonal to the second row R2, and a twenty third connection C23extending in the direction of the second row R2to be connected to the second neck portion532.

The connection structure of the first tab521including the eleventh connection C11, the twelfth connection C12, and the thirteenth connection C13and the connection structure of the second tab522including the twenty first connection C21, and twenty second connection C22, and the twenty third connection C23may be connected to the body portion51through a long distance.

Therefore, the difference between an entire distance to a final output end of the tab member50through the body portion51from the connection structure of the first tab521and an entire distance to a final output end of the tab member50through the body portion51from the connection structure of the second tab522may be minimized. That is, the voltage difference between the battery cell of the first row R1and the battery cell10of the second row R2may be minimized (e.g., equal to zero).

Referring toFIG.3andFIG.4, the body portion51may be disposed between the first row R1and the second row R2of the battery cells10and may be connected in the second direction. The first tab521may be connected to the positive terminals41in the first row R1. The first tab521may be connected to the body portion51and may be disposed in the first row R1. The second tab522may be connected to the negative terminals42in the second row R2. The second tab522may be connected to the body portion51and may be disposed in the second row R2.

The first neck portion531may have a pair of the electrically connected first tabs521, and may connect the positive terminals41of the two battery cells10in parallel. The first neck portion531may avoid (e.g., be disposed around) the two battery cells10disposed in the direction of the first row R1and may be disposed between the two battery cells10in the direction of the first row R1. The one pair of the first tabs521may be connected to the first neck portion531, may avoid the two battery cells10disposed in the direction of the first row R1, and may be connected to the respective positive terminals41of the two battery cells10.

The second neck portion532may have a pair of electrically connected second tabs522and may connect the negative terminals42of the two battery cells10in parallel. The second neck portion532may avoid the two battery cells10disposed in the direction of the second row R2and may be disposed between the two battery cells10in the direction of the second row R2. The one pair of the second tabs522may be connected to the second neck portion532, may avoid the two battery cells10disposed in the direction of the second row R2, and may be connected to the respective negative terminals42of the two battery cells10.

The first tab521and the first neck portion531in the first row R1may generate a same current path of the two battery cells10disposed in the first row R1up to the body portion51. Therefore, the voltage difference between the battery cells10in the first row R1may be minimized (e.g., equal to zero).

The second tab522and the second neck portion532in the second row R2may generate a same current path of the two battery cells10disposed in the second row R2up to the body portion51. Therefore, the voltage difference between the battery cells10in the second row R2may be minimized (e.g., equal to zero).

The body portion51may be connected to the first neck portion531and the second neck portion532and may connect the two battery cells10connected in parallel in the first row R1and the two battery cells10connected in parallel in the second row R2in series.

Therefore, a current of the two battery cells10connected in parallel in the first row R1may flow to the body portion51, and a current of the two battery cells10connected in parallel in the second row R2may flow to the body portion51.

In this instance, the body portion51of the tab member50may be shared with the first row R1and the second row R2so the voltage difference between the battery cells10of the first row R1and the second row R2may be minimized (e.g., equal to zero). Hence, reduction of lifespan of the battery cells10may be prevented.

The tab member50may further include a bent portion55connected to an end of the body portion51disposed between the first row R1and the second row R2and formed to have a downward convex cross-section on a lateral surface. The bent portion55may increase in a direction of an angle (θ) dislocated on the lateral surfaces of the two battery cells10.

FIG.5shows a cross-sectional view with respect to a line V-V of the tab member ofFIG.3. Referring toFIG.5, the bent portion55has a curvature radius, and an upper-end bending start point (BSP) of the curvature radius may be disposed on a diagonal upper portion of round portions (RP) formed on respective ends of the battery cell10in the axal direction.

The bent portion55may be installed in the tab member50for connecting the battery management system (BMS)30and the battery cell10, and may absorb and/or ease impacts or vibration transmittable in respective directions between the battery management system30and the battery cell10.

The bent portion55may form a gap (G) between the BMS30and the lateral surface of the battery cell10. The gap (G) may increase a degree of freedom of assembling the tab member50and may ease setting for welding the battery cell10and the tab member50.

Various embodiments of the present disclosure will now be described. Components and configurations which are the same as the first embodiment and the above-described embodiments will be omitted, and different configurations will now be described.

FIG.6shows a top plan view on a tab member for connecting four battery cells in a rechargeable battery module according to a second embodiment of the present disclosure, andFIG.7shows a cross-sectional view with respect to a line VII-VII ofFIG.6. Referring toFIG.6andFIG.7, regarding the tab member250of the rechargeable battery module2according to a second embodiment, the bent portion55has a curvature radius, and an upper-end bending start point BSP2of the curvature radius may be disposed on an upper portion of the round portion (RP) formed on respective ends of the battery cell10in the axial direction (top to bottom direction inFIG.7).

The tab member250is connected to the second tab522by welding, and may contact the battery cell10on the lateral surface of the bent portion55to thus make the connection of the tab member250and the battery cell10firmer. Therefore, the bent portion55may be installed in the tab member250for connecting the battery management system (BMS)30and the battery cell10, may be more firmly connected to the battery cell10than to the battery management system30, and may absorb and/or ease the impacts or vibration transmittable in the respective directions.

FIG.8shows a cross-sectional view of a rechargeable battery module according to a third embodiment of the present disclosure. Referring toFIG.8, regarding the tab member350of the rechargeable battery module3according to a third embodiment, the bent portion355may have a curvature radius, and the upper-end bending start point (BSP) of the curvature radius may be disposed on the diagonal upper portion of the round portion (RP) formed on the respective ends of the battery cell10in the axial direction.

The bent portion355may be installed in the tab member350for connecting the battery management system30and the battery cell10, and may absorb and/or ease the impacts or vibration transmittable in the respective directions between the battery management system30and the battery cell10.

The bent portion355may further include a lateral convex surface56that is convex toward the lateral surface of the battery cell10. The lateral convex surface56may increase a degree of freedom of assembling the tab member350, may ease the setting for welding the battery cell10and the tab member350, may contact the battery cell10, and may make the connection of the tab member350and the battery cell10firmer.

FIG.9shows a cross-sectional view of a rechargeable battery module according to a fourth embodiment of the present disclosure. Referring toFIG.9, regarding the tab member450applied to the rechargeable battery module4according to a fourth embodiment, the bent portion455may be formed to have a curved cross-section that is downward convex on the lateral surface (e.g., convex in a direction downwards, perpendicular to the lateral surface). For example, the curved cross-section may have a U-shape.

The tab member450may be connected to the second tab522by welding, may contact battery cell10on the lateral surface of the bent portion455formed to be a curved cross-section, and may make the connection of the tab member450and the battery cell10firmer. Therefore, the bent portion455may be installed in the tab member450for connecting the battery management system (BMS)30and the battery cell10, may be connected more firmly to the battery cell10than to the battery management system30, and may absorb and/or ease the impacts or vibration transmittable in the respective directions.

FIG.10shows a cross-sectional view of a rechargeable battery module according to a fifth embodiment of the present disclosure. Referring toFIG.10, regarding the tab member550applied to the rechargeable battery module5according to a fifth embodiment, the bent portion555may be formed to have an angled cross-section that is downward convex on the lateral surface (e.g., convex in a direction downwards, perpendicular to the lateral surface). For example, the angled cross-section may have a V-shape.

The tab member550may be connected to the second tab522by welding, may contact the battery cell10on the lateral surface of the bent portion555formed to be an angled cross-section, and may make the connection of the tab member550and the battery cell10firmer. Therefore, the bent portion555may be installed in the tab member550for connecting the battery management system (BMS)30and the battery cell10, may be connected more firmly to the battery cell10than to the battery management system30, and may absorb and/or ease the impacts or vibration transmittable in the respective directions.

A variable gap G2set between the bent portion555and the battery cell10may increase the degree of freedom of assembling the tab member450to thus ease the setting for welding the battery cell10and the tab member450.

An embodiment of the present disclosure provides a method of manufacturing a rechargeable battery module. The method may comprise providing holder for receiving a plurality of battery cells; arranging the plurality of battery cells in the holder in a first row and a second row parallel to the first row; installing a tab member on the holder, positioned relative to the first row and the second row wherein installing the tab member comprises welding the tab member to respective electrode terminals of the plurality of battery cells, and wherein the tab member comprises: a body portion disposed between the first row and the second row, a first neck portion connected to the body portion, disposed along the first row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the first row with a first tab, and a second neck portion connected to the body portion, disposed along the second row, and connected to electrode terminals of one or more battery cells of the plurality of battery cells arranged in the second row with a second tab.

DESCRIPTION OF SYMBOLS