Patent Description:
In general, a secondary battery is rechargeable and dischargeable, unlike a primary battery that is not rechargeable. A secondary battery is used as an energy source in mobile devices, electric vehicles, hybrid vehicles, electric bicycles, and uninterruptible power supplies, and may be used in the form of a single battery or a battery pack, in which a plurality of batteries are electrically connected as a single unit, according to kinds of external devices to which the secondary battery is applied.

A small-sized mobile device, such as a mobile phone, is operable with an output and a capacity of a single battery, but electric vehicles or hybrid vehicles consume a relatively large amount of electric power to drive for a long time at a high electric power output and, thus, use a pack type battery including a plurality of batteries. In addition, an output voltage or an output current may increase according to the number of batteries included in a module.

According to an aspect of one or more embodiments, a battery pack is suitable for a compact type device by reducing the space occupied by a connection tab that mediates electric connection between a battery cell and a circuit board.

According to another aspect of one or more embodiments, a battery pack, to which a low-resistive design is applied, has a reduced length signal transmission path.

According to another aspect of one or more embodiments, a battery pack has an improved support strength at a connection tab that mediates electric connection between a battery cell and a circuit board.

Additional aspects will be set forth, in part, in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to the invention, there is provided a battery pack according to claim <NUM>. Preferred features are set out in the dependent claims.

Since the connection tab extends into the valley between adjacent battery cells, it is to some extent protected from damage by the surrounding battery cells.

These and/or other aspects will become apparent and more readily appreciated from the following description of one or more embodiments, taken in conjunction with the accompanying drawings, in which:.

Referring to the drawings, a battery pack according to the invention includes a plurality of battery cells <NUM>, may include a cell holder <NUM> for accommodating the battery cells <NUM>, and includes a circuit board <NUM> for controlling charging/discharging operations of the battery cells <NUM>.

The battery cell <NUM> has different electrodes at opposite ends thereof in a length direction, and is formed as a cylinder. A concave valley region "g" is formed between neighbouring battery cells <NUM>, outer circumferential surfaces of which may be in contact with each other.

The elongate battery cells <NUM> are arranged side-by-side in the battery pack.

The plurality of battery cells <NUM> include two or more battery cells <NUM>. The plurality of battery cells <NUM> may be electrically connected to one another in a serial manner, a parallel manner, or a combined parallel-serial manner. The plurality of battery cells <NUM> are electrically connected to one another via a connection member <NUM>, e.g., the
The circuit board may include a connection hole to which the connection portion is inserted.

The lead portion may extend diagonally with a slant inclination angle so as to concurrently follow the first direction and a second direction that is different from the first direction.

The circuit board may be located above the battery cells in the first direction.

The connection member may include: a first welding portion and a second welding portion with respect to the battery cells; and a cut portion crossing between the first welding portion and the second welding portion.

The battery pack may further include a cell holder configured to accommodate the battery cells, wherein an internal surface of the cell holder may surround the battery cells, and the circuit board is arranged above an external surface of the cell holder.

According to the invention there is also provided a battery pack comprising a plurality of battery cells having battery terminals at opposite ends thereof, the battery cells being arranged side by side into a pack configuration such that a valley is formed between pairs of adjacent battery cells, a circuit board disposed along a side surface of the pack configuration to control charging and discharging operations of the battery cells, a connection member arranged at one end of the pack configuration to connect selected ones of the battery terminals together, a connection tab having a first portion that extends from the connection member, a second portion in the valley between one of the pairs of adjacent battery cells and a bent portion that joins the first and second portions, the connection tab further comprising a connection arrangement that extends from the second portion towards the circuit board to connect the connection member to the circuit board.

The connection arrangement may comprise a third portion extending from the second portion towards the circuit board, and a fourth portion connecting the third portion to the circuit board. The third portion may be arranged to extend diagonally between the second and fourth portions, permitting deflection of the third portion, so providing some elastic support to the circuit board.

The batteries may be cylindrical or near cylindrical, as long as a valley is formed between them when they are arranged next to one another.

The connection member may be a planar plate. The first portion of the connection tab may extend in the same plane as that of the planar plate and be bent at a right angle to form the second portion.

Referring to the drawings, a battery pack according to an embodiment may include a plurality of battery cells <NUM>, a cell holder <NUM> for accommodating the battery cells <NUM>, and a circuit board <NUM> for controlling charging/discharging operations of the battery cells <NUM>.

In an embodiment, the battery cell <NUM> may have different electrodes at opposite ends thereof in a length direction, and may be formed as a cylinder. A concave valley region "g" may be formed between neighbouring battery cells <NUM>, outer circumferential surfaces of which may be in contact with each other.

The elongate battery cells <NUM> may be arranged side-by-side in a battery pack.

The plurality of battery cells <NUM> may include two or more battery cells <NUM>. The plurality of battery cells <NUM> may be electrically connected to one another in a serial manner, a parallel manner, or a combined parallel-serial manner. The plurality of battery cells <NUM> may be electrically connected to one another via a connection member <NUM>, e.g., the plurality of battery cells <NUM> may be connected in parallel by the connection member <NUM> that electrically connects the same polarities of the neighbouring battery cells <NUM>, or may be connected in series by the connection member <NUM> that electrically connects opposite polarities of the neighbouring battery cells <NUM>.

For example, a connection member <NUM> may electrically connect four battery cells <NUM> to one another, and the connection member <NUM> may connect the neighbouring battery cells <NUM> in a first direction (e.g., a Z1-direction) in parallel while connecting the neighbouring battery cells <NUM> in a second direction (e.g., a Z2-direction) in series. In an embodiment, the connection member <NUM> may connect the same polarities of the battery cells <NUM> that make a pair in the first direction (e.g., the Z1-direction) to connect the corresponding battery cells <NUM> in parallel, and may connect opposite polarities of the battery cells <NUM> that make a pair in the second direction (e.g., the Z2-direction) to connect the corresponding battery cells <NUM> in series.

By connecting the battery cells <NUM> in parallel in the first direction (e.g., the Z1-direction) and connecting the battery cells <NUM> in series in the second direction (e.g., the Z2-direction), a combined connection of the parallel-serial connections may be obtained. Accordingly, an output capacity of the battery pack may be increased or optimized to be high capacity and high output. In an embodiment, the battery cells <NUM> may be connected in parallel in the first direction (e.g., the Z1-direction) and may be connected in series in the second direction (e.g., the Z2-direction) by using one connection member <NUM>, and, thus, the number of connection members <NUM> for connecting the neighbouring battery cells <NUM> may be reduced.

The battery cells <NUM> may be accommodated in the cell holder <NUM>. The cell holder <NUM> may provide an accommodation space having a shape matching or corresponding to that of the battery cells <NUM>. For example, the cell holder <NUM> may include a plurality of cylindrical accommodation spaces that are arranged in the first and second directions (e.g., the Z1 and Z2-directions). The cell holder <NUM> has an internal surface <NUM> facing the battery cells <NUM> to surround the battery cells <NUM>, and an external surface <NUM> to support the circuit board <NUM>.

The cell holder <NUM> may have any of various shapes, provided that the accommodation space for the battery cells <NUM> is provided. For example, the cell holder <NUM> may be formed as one body or may be formed by combining different members. In an embodiment, for example, two different members arranged between the battery cells <NUM> and the circuit board <NUM> may be coupled to each other to form the cell holder <NUM>. Here, the external surface <NUM> of the cell holder <NUM> may denote a support surface that supports the circuit board <NUM>.

The battery pack may further include the circuit board <NUM> for controlling charging/discharging operations of the battery cells <NUM>. The circuit board <NUM> obtains status information of the battery cells <NUM> and may control the charging/discharging operations of the battery cells <NUM> based on the status information. For example, the circuit board <NUM> may obtain status information, such as a temperature and a voltage of each battery cell <NUM>, and may sense incorrect operations, such as over-charging, over-discharging, and over-heating, based on the status information to take protective measures, such as suspension of the charging/discharging operations of the battery cell <NUM>. The circuit board <NUM> may be arranged on the external surface <NUM> of the cell holder <NUM>. The circuit board <NUM> may obtain the status information from the battery cells <NUM>, and may be connected to the battery cells <NUM> via a connection tab <NUM>.

The connection tab <NUM> may include a first portion <NUM> extending upward to the external surface <NUM> of the cell holder <NUM> from the connection member <NUM> and a second portion <NUM> arranged on the external surface <NUM> of the cell holder <NUM>, and may further include a bent portion <NUM> connecting the first and second portions <NUM> and <NUM> to each other. The first portion <NUM> may extend from the connection member <NUM> in the first direction (e.g., the Z1-direction). For example, the first portion <NUM> may extend from the connection member <NUM> across the valley region "g" between the neighbouring battery cells <NUM>.

In an embodiment, the battery cell <NUM> may have a cylindrical shape, and the concave valley region "g" is between the neighbouring battery cells <NUM>. Here, the first portion <NUM> may extend across the valley region "g" between the neighbouring battery cells <NUM> to reduce a spatial height occupied by the connection tab <NUM>.

The second portion <NUM> may extend from the first portion <NUM> in a different direction from the first direction <NUM>, e.g., in a length direction of the battery cell <NUM>, via the bent portion <NUM>. When the first portion <NUM> extends across the valley region "g" between the neighbouring battery cells <NUM>, the second portion <NUM> may be located within the valley region "g. " As described above, since the second portion <NUM> is located within the valley region "g" between the neighbouring battery cells <NUM>, fluctuation of the connection tab <NUM> may be prevented or substantially prevented with respect to external vibrations or shock, and the connection tab <NUM> may be protected.

The bent portion <NUM> of the connection tab <NUM> may be arranged within a battery area S. Here, the battery area S may denote a region occupied by a group of battery cells <NUM> electrically connected to one another. For example, the battery area S may denote a square region in the first and second directions (e.g., the Z1 and Z2-directions), which includes a region of the battery cells <NUM> electrically connected to one another via the connection member <NUM>. Here, for example, the connection member <NUM> might electrically connect <NUM> different battery cells <NUM> in <NUM> × <NUM> array. In another embodiment, the battery area S may denote a rectangular region in the first and second directions Z1 and Z2, which includes a region of the battery cells <NUM> electrically connected to one another via the connection member <NUM>. Here, for example, the connection member <NUM> might electrically connect <NUM> different battery cells <NUM> in <NUM> × <NUM> array. In another embodiment, the battery area S may denote parallelogram, which includes a region of the battery cells <NUM> electrically connected to one another via the connection member <NUM>. Here, for example, the connection member <NUM> might electrically connect battery cells stack in staggered manner in <NUM> × <NUM> array. In another embodiment, the battery area S may denote trapezoid, which includes a region of the battery cells <NUM> electrically connected to one another via the connection member <NUM>. Here, for example, the connection member <NUM> might electrically connect battery cells stack in staggered manner with <NUM> upper battery cells and <NUM> lower battery cells.

When the bent portion <NUM> of the connection tab <NUM> is arranged within the battery area S, the first portion <NUM> in front of the bent portion <NUM> may extend across the valley region "g" between the neighbouring battery cells <NUM> and the second portion <NUM> behind the bent portion <NUM> may be located within the valley region "g" between the neighbouring battery cells <NUM>. This will be described in further detail later.

In an embodiment, the connection tab <NUM> may be directly connected to the circuit board <NUM>. Here, the connection tab <NUM> being directly connected to the circuit board <NUM> denotes that an additional connection member, e.g., a flexible wire, is not arranged between the connection tab <NUM> and the circuit board <NUM> for mediating the electric connection.

In an embodiment, the connection tab <NUM> may further include a connection portion <NUM> that is directly connected to the circuit board <NUM>. The connection portion <NUM> may be inserted to a connection hole <NUM>' of the circuit board <NUM>, and may be fixed to a connection pad (not shown) around the connection hole <NUM>' via soldering.

The connection tab <NUM> may further include a lead portion <NUM> extending between the connection portion <NUM> and the second portion <NUM>. The lead portion <NUM> may extend from the second portion <NUM> towards the connection hole <NUM>' of the circuit board <NUM>. A direction in which the lead portion <NUM> extends may be any of various directions depending on a design of the circuit board <NUM>, such as, for example, according to an arrangement of the connection hole <NUM>' of the circuit board <NUM>. In one embodiment, the lead portion <NUM> may extend towards the connection hole <NUM>' along a side direction of the circuit board <NUM>.

In an embodiment, the lead portion <NUM> may extend along the second direction (e.g., the Z2-diretion) towards the connection hole <NUM>' of the circuit board <NUM> that is arranged above the battery cells <NUM>. That is, the lead portion <NUM> may extend along a side direction of the circuit board <NUM>, and at the same time, extend upward towards the circuit board <NUM> to have a diagonal line shape with an inclination angle.

In an embodiment, for example, the circuit board <NUM> may be formed having a rectangular shape including a pair of long side portions extending in the second direction (e.g., the Z2-direction) along a direction in which the battery cells <NUM> are arranged and a pair of short side portions between the pair of longer side portions. Here, the lead portion <NUM> may extend at an oblique angle of inclination that follows the direction of the long side portion (e.g., the second direction) and the upward direction (e.g., the first direction).

The battery cell <NUM> may be electrically connected to neighbouring battery cells <NUM> via the connection member <NUM>. In an embodiment, for example, the connection member <NUM> may electrically connect four battery cells <NUM> to one another, and the connection member <NUM> may connect the neighbouring battery cells <NUM> in the first direction (e.g., a Z1-direction) in parallel while connecting the neighbouring battery cells <NUM> in the second direction (e.g., a Z2-direction) in series. In an embodiment, the connection member <NUM> may connect the same polarities of the battery cells <NUM> that make a pair in the first direction (e.g., the Z1-direction) to connect the corresponding battery cells <NUM> in parallel, and may connect opposite polarities of the battery cells <NUM> that make a pair in the second direction (e.g., the Z2-direction) to connect the corresponding battery cells <NUM> in series.

In an embodiment, the first portion <NUM> of the connection tab <NUM> may extend in the first direction (e.g., the Z1-direction) that is the parallel connection direction. The first portion <NUM> of the connection tab <NUM> may extend in one of the parallel connection direction or the serial connection direction exclusively of the other. That is, according to one embodiment, since the first portion <NUM> of the connection tab <NUM> extends in the first direction (e.g., the Z1-direction) that is the parallel connection direction, the first portion <NUM> does not extend in the second direction (e.g., the Z2-direction) that is the serial connection direction.

Since the connection member <NUM> performs the serial connection and the parallel connection concurrently or simultaneously, the output capacity of the battery pack may be increased or optimized at high output and high capacity. In addition, the serial connection and the parallel connection may be performed at the same time by using one connection member <NUM> to reduce the number of the connection members <NUM>. As described above, the parallel connection direction and the serial connection direction that are exclusive to each other may be defined with respect to one connection member <NUM>, and, thus, the extension direction of the first portion <NUM> of the connection tab <NUM> may be set as one exclusive direction of the parallel connection direction and the serial connection direction.

The lead portion <NUM> of the connection tab <NUM> may extend in a diagonal direction that concurrently or simultaneously follows the first direction (e.g., the Z1-direction) that is the parallel connection direction and the second direction (e.g., the Z2-direction) that is the serial connection direction. The lead portion <NUM> of the connection tab <NUM> extends toward the connection hole <NUM>' of the circuit board <NUM>, and, as described above, since the parallel connection direction and the serial connection direction are exclusively defined with respect to one connection member <NUM>, the extension direction of the lead portion <NUM> of the connection tab <NUM> may be set as the diagonal direction that is between or oblique to each of the parallel connection direction and the serial connection direction.

The circuit board <NUM> may form a circuit portion for controlling the charging/discharging operations of the battery cells <NUM>. The circuit board <NUM> may receive status information of the battery cell <NUM>, e.g., a voltage or a temperature of the battery cell <NUM>, through the connection tab <NUM>. In addition, the circuit board <NUM> may control the charging/discharging operations of the battery cell <NUM> based on the status information of the battery cell <NUM>. The connection tab <NUM> is electrically and thermally connected to the battery cell <NUM> to share the voltage or the temperature information of the battery cell <NUM>, and, thus, the circuit board <NUM> may receive the status information of the battery cell <NUM> through the connection tab <NUM>.

The circuit board <NUM> includes the connection hole <NUM>' for connecting to the connection tab <NUM>. Although not shown in the drawings, a connection pad (not shown) may be provided around the connection hole <NUM>', and the status information transmitted through the connection tab <NUM> may be transferred to a requesting part of the circuit board <NUM>. In an embodiment, the connection portion <NUM> of the connection tab <NUM> may be directly inserted to the connection hole <NUM>' of the circuit board <NUM>. Also, in an embodiment, the connection portion <NUM> of the connection tab <NUM> and the connection pad (not shown) may be fixed to each other via soldering.

The circuit board <NUM> may be supported by the connection tab <NUM>. In an embodiment, for example, the circuit board <NUM> is fixed on the external surface <NUM> of the cell holder <NUM>, and may be supported by the connection tab <NUM> extending above the external surface <NUM> of the cell holder <NUM>. For example, a plurality of connection tabs <NUM> may extend above the external surface <NUM> of the cell holder <NUM>, and the circuit board <NUM> may be fixedly positioned on the external surface <NUM> of the cell holder <NUM> via the connection tabs <NUM> that are fixedly inserted to different connection holes <NUM>' from one another. Here, shocks or vibrations applied to the circuit board <NUM> may be reduced through elastic support of the connection tabs <NUM>, and the circuit board <NUM> may be elastically supported by the lead portion <NUM> that extends diagonally in each of the connection tabs <NUM>.

In an embodiment, the connection members <NUM> may be arranged in alternating patterns at front and rear portions of the battery pack. In an embodiment, for example, one of the connection members <NUM> arranged at a front portion of the battery pack connects third and fourth battery cells <NUM> to each other in the second direction (e.g., the Z2-direction), and one of the connection members <NUM> arranged at a rear portion of the battery pack may not connect the third and fourth battery cells <NUM>, but may connect second and third battery cells <NUM> to each other. As such, the plurality of battery cells <NUM> may be connected in series through the arrangement of the connection members <NUM> that alternate at the front and rear portions of the battery pack.

In an embodiment, the battery cells <NUM> in a first row and a second row are connected to one another in parallel along the first direction (e.g., the Z1-direction) that is the parallel connection direction, and neighbouring battery cells <NUM> along the second direction (e.g., the Z2-direction) may be connected to one another in series because the connection tabs <NUM> are arranged alternately with each other along the second direction (e.g., the Z2-direction) that is the serial connection direction.

The connection tab <NUM> may extend from the connection member <NUM> and, in an embodiment, may be integrally formed with the connection member <NUM>. For example, the connection tab <NUM> may include a metal plate integrally formed with the connection member <NUM>. The connection tab <NUM> may transfer voltage information of the battery cell <NUM> to the circuit board <NUM>. For example, the circuit board <NUM> may perform a balancing operation based on the voltage information of the battery cell <NUM> transferred through the connection tab <NUM>. The connection tab <NUM> may have a narrow or minimum width provided that the voltage information of the battery cell <NUM> may be transferred, and such that the width of the connection tab <NUM> may not break due to Joule heat. In an embodiment, for example, the connection tab <NUM> may have a width of <NUM>.

The connection tab <NUM> may include the first portion <NUM> extending from the connection member <NUM> toward the external surface <NUM> of the cell holder <NUM> in the first direction (e.g., the Z1-direction), and the second portion <NUM> extending from the first portion <NUM> to be arranged on the external surface <NUM> of the cell holder <NUM>. In addition, the connection tab <NUM> may include the bent portion <NUM> through which the direction is changed between the first and second portions <NUM> and <NUM>.

The bent portion <NUM> denotes a bent portion of the connection tab <NUM>, and when the connection tab <NUM> has a plurality of bent portions, for example, the bent portion <NUM> may correspond to a bent portion that is the closest to the battery cell <NUM>. As will be described later, the bent portion <NUM> may be located in the battery area S.

Referring to <FIG> and <FIG>, the bent portion <NUM> of the connection tab <NUM> may be arranged within the battery area S. Here, the battery area S may denote a region occupied by a group of battery cells <NUM> electrically connected to one another. In an embodiment, the battery area S may correspond to a square area that includes areas of the plurality of battery cells <NUM> connected by one of the connection members <NUM> in the first and second directions (e.g., the Z1 and Z2-directions).

In an embodiment, the bent portion <NUM> of the connection tab <NUM> being arranged within the battery area S denotes that the bent portion <NUM> of the connection tab <NUM> is arranged within the battery area S without protruding from the battery area S, and, as a result, the battery pack of a compact type may be manufactured.

Alternatively stated, the first, second and bent portions <NUM>, <NUM>, <NUM> of the connection tab (<NUM>) lie within the region or envelope S that is defined by imaginary planes that lie along and touch the outermost side surfaces of the adjacent battery cells, as shown for example in <FIG>, so that the first, second and bent portions do not extend outside the envelope and are to some extent protected by the surrounding battery cells. The battery pack can also be made more compact by using the space between the battery cells for connection to the circuit board.

The connection tab <NUM> protrudes upward from the connection member <NUM> in the first direction (e.g., the Z1-direction) to extend over the external surface <NUM> of the cell holder <NUM>. Here, the connection tab <NUM> may protrude upward to the external surface <NUM> up to the bent portion <NUM> (corresponding to the first portion <NUM>) and may extend in parallel with the external surface <NUM> of the cell holder <NUM> after the bent portion <NUM> (corresponding to the second portion <NUM>). The bent portion <NUM> of the connection tab <NUM> may provide criteria with respect to a spatial height occupied by the connection tab <NUM>, and if the bent portion <NUM> were outside of the battery area S, the spatial height occupied by the connection tab <NUM> would be increased, and then a dead space would be increased and not suitable for the compact structure.

The bent portion <NUM> of the connection tab <NUM> may be arranged within the battery area S. In an embodiment, the connection tab <NUM> (in particular, the first portion <NUM> of the connection tab <NUM>) may extend across the valley region "g" between the neighbouring battery cells <NUM>, and the bent portion <NUM> of the connection tab <NUM> may be provided at a height that is the same or lower than that of a peak point PE of the surface (e.g., the cylindrical surface) of the battery cell. That is, since the connection tab <NUM> (in particular, the first portion <NUM> of the connection tab <NUM>) extends across the valley region "g" of the neighbouring battery cells <NUM>, the bent portion <NUM> of the connection tab <NUM> may be formed at a low height where the bent portion <NUM> does not protrude beyond the peak point PE of the surface (e.g., the cylindrical surface) of the battery cell <NUM>.

The bent portion <NUM> of the connection tab <NUM> being arranged within the battery area S denotes that the first portion <NUM> of the connection tab <NUM> is relatively short, that is, a signal transmission path of the connection tab <NUM> is reduced to provide a low-resistive design, and, thus, the status information of the battery cell <NUM> may be transferred with high accuracy.

When the first portion <NUM> of the connection tab <NUM> extends across the valley region "g" between the neighbouring battery cells <NUM>, the second portion <NUM> of the connection tab <NUM> past the bent portion <NUM> may be arranged within the valley region "g" between the neighbouring battery cells <NUM>. When the connection tab <NUM> is arranged in the valley region "g" between the neighbouring cells <NUM>, the connection tab <NUM> may be fixedly positioned. That is, the connection tab <NUM> may not interfere with other components in the valley region "g" and may be firmly supported even when there are external shocks or vibrations.

Referring to <FIG>, in an embodiment, the connection member <NUM> may be coupled to the battery cells <NUM> via welding. For example, the connection member <NUM> may include first and second welding portions P1 and P2 corresponding to each battery cell <NUM>, and a cut portion C crossing between the first and second welding portions P1 and P2. Although not shown in the drawings, the connection member <NUM> and the battery cell <NUM> may be welded to each other by a welding current applied from two welding electrodes (not shown) having different polarities, and, then, the first and second welding portions P1 and P2 that are different from each other may be formed in the connection member <NUM>. Here, the cut portion C may be formed between the first and second welding portions P1 and P2. The cut portion C may prevent or substantially prevent leakage current, e.g., the welding current applied to the first and second welding portions P1 and P2 from flowing along the surface of the connection member <NUM>, not along bonded surfaces between the connection member <NUM> and the battery cell <NUM>. The cut portion C increases a path connecting between the first and second welding portions P1 and P2 so as to prevent or substantially prevent the first and second welding portions P1 and P2 from directly connecting to each other via the surface of the connection member <NUM>.

According to one or more embodiments, the space occupied by the connection tab that mediates the electric connection between the battery cells and the circuit board may be reduced so as to form a compact structure of the battery pack. In addition, the signal transmission path through the connection tab is reduced to provide the low-resistive structure. The space occupied by the connection tab may be reduced by utilizing the valley region between the neighbouring battery cells, and at the same time, the connection tab is arranged in the valley region so as not to interfere with other components, and the connection tab may be firmly supported even when there are external shocks or vibrations applied to the battery pack.

It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation.

Claim 1:
A battery pack comprising:
a plurality of cylindrical battery cells (<NUM>) having battery terminals at opposite ends thereof, the battery cells being arranged side by side into a pack configuration such that a concave valley region is formed between pairs of adjacent battery cells;
a circuit board (<NUM>) disposed along a side surface of the pack configuration to control charging and discharging operations of the battery cells (<NUM>);
a connection member (<NUM>) arranged to connect selected ones of the battery terminals together;
a connection tab (<NUM>) having a first portion (<NUM>) that extends from the connection member, a second portion (<NUM>) in the concave valley region between one of the pairs of adjacent battery cells and a bent portion (<NUM>) that joins the first and second portions, the connection tab further comprising a connection arrangement (<NUM>, <NUM>) that extends from the second portion (<NUM>) towards the circuit board (<NUM>) to connect the connection member (<NUM>) to the circuit board (<NUM>), and
wherein the connection arrangement (<NUM>, <NUM>) comprises:
a connection portion (<NUM>); and
a lead portion (<NUM>) extending diagonally from the second portion (<NUM>) to the connection portion (<NUM>).