Patent Description:
A rechargeable battery repeats charging and discharging operations, unlike a primary cell. A small rechargeable battery is used for portable small electronic devices such as a mobile phone, a laptop computer, or a camcorder. A large capacity and high density rechargeable battery is used to store motor driving power or energy of hybrid vehicles and electric vehicles.

The rechargeable battery may be used as a single cell as in a small electronic device, or to achieve a large capacity for the purpose of driving a motor it may be used as a module in which a plurality of cells are electrically connected and a pack in which modules are electrically connected.

A flexible printed circuit (FPC) for sensing voltages or temperatures of the cells and transmitting them to a cell supervision circuit is installed in the rechargeable battery pack.

The flexible printed circuit and a cell supervision circuit (CSC) (or a cell monitor circuit (CMC)) are electrically connected to each other using a connector.

However, if the connector is attached/detached, a circuit connected to the connector may be frequently damaged so the durability of installation may be deteriorated.

The present disclosure provides a rechargeable battery pack for electrically connecting a flexible printed circuit and a cell supervision circuit by using an electrically conductive solder instead of a connector.

An embodiment of the present disclosure provides a rechargeable battery pack including: a cell assembly including at least one battery cell; a side frame accommodating the cell assembly; a flexible printed circuit (FPC) electrically connected to the cell assembly and configured to sense one or more properties of the battery cell; and a cell supervision circuit electrically connected to the flexible printed circuit and on one side of the side frame.

The flexible printed circuit is electrically connected to the cell supervision circuit by an electrically conductive solder.

The electrically conductive solder may include a solder or a conductive glue for electrically connecting the flexible circuit substrate and the cell supervision circuit.

The flexible printed circuit may include a number of circuit lines and a number of conductive pad portions at respective ends of the circuit lines electrically connected to the cell supervision circuit.

At least one conductive pad portion may protrude from the end of a circuit line with a size that is greater than a width of the circuit line and may be electrically connected to the cell supervision circuit by the electrically conductive solder.

The conductive pad portion may include a first expansion pad protruding from a first side of the circuit line in a width direction, and a second expansion pad protruding from a second side of the circuit line in the width direction.

The first expansion pad and the second expansion pad may protrude in a round shape from the end of the circuit line in directions that are opposite to each other.

A round groove may be between the first expansion pad and the second expansion pad.

A first step side connected to a lateral side of the flexible printed circuit may be at an end of the first expansion pad.

A second step side connected to a lateral side of the flexible printed circuit may be at an end of the second expansion pad.

A plated layer may be on surfaces of the first step side and the second step side.

A first spaced distance between an outer surface of the first expansion pad and an outer surface of the second expansion pad may be approximately <NUM> to approximately <NUM> times a spaced distance between adjacent circuit lines.

The first spaced distance may be approximately <NUM> to approximately <NUM> times a second spaced distance between a step of the first expansion pad and a step of the second expansion pad.

The electrically conductive solder may be a cream solder applied to the first step side, the second step side, and the round groove, may be bonded by laser heat, and may be electrically connected to the cell supervision circuit.

The electrically conductive solder may be a wire solder applied to the first step side, the second step side, and the round groove, may be bonded by laser heat, and may be electrically connected to the cell supervision circuit.

At least one circuit line may include a sub-pad portion spaced from the conductive pad portion and electrically connected to the cell supervision circuit by the electrically conductive solder.

The circuit line may include a slot hole in the sub-pad portion into which the electrically conductive solder is inserted.

A surface of the electrically conductive solder may be conformally coated.

According to the embodiment, the flexible printed circuit is electrically connected to the cell supervision circuit not by using an additional terminal but by using the electrically conductive solder such as a solder, thereby preventing disconnection of lines which might otherwise occur due to pressurized damages at the connected portion of the circuit, and thus allowing stable connection.

The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the disclosure are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the scope of the present disclosure. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

<FIG> shows a perspective view of a rechargeable battery pack according to a first embodiment of the present disclosure, and <FIG> shows a schematic perspective view of a flexible circuit substrate and a cell supervision circuit of <FIG> electrically connected by an electrically conductive solder.

As shown in <FIG> and <FIG>, the rechargeable battery pack <NUM> according to a first embodiment of the present disclosure includes a cell assembly <NUM> including at least one battery cell <NUM>, a side frame <NUM> for receiving (accommodating) the cell assembly <NUM>, a flexible printed circuit (FPC) <NUM> electrically connected to the cell assembly <NUM> and configured to sense one or more properties of the battery cell <NUM>, and a cell supervision circuit <NUM> connected to the flexible printed circuit <NUM> and installed on one side of the side frame <NUM>. The flexible printed circuit <NUM> is electrically connected to the cell supervision circuit <NUM> by an electrically conductive solder <NUM>.

A plurality of battery cells <NUM> may be configured with a conventional rechargeable battery for repeatedly performing a charging and discharging operation.

The side frame <NUM> may include a first side frame <NUM> for supporting first lateral sides of a plurality of battery cells <NUM>, a second side frame <NUM> for supporting second lateral sides of the battery cells <NUM>, a first end frame <NUM> of which respective ends are connected to first ends of the first side frame <NUM> and the second side frame <NUM>, and a second end frame <NUM> of which respective ends are connected to second ends of the first side frame <NUM> and the second side frame <NUM>.

The first side frame <NUM> may be installed to support first sides of the battery cells <NUM>.

The second side frame <NUM> may be installed to support seconds sides of the battery cells <NUM>.

The first end frame <NUM> may be installed to connect the first ends of the first side frame <NUM> and the second side frame <NUM>. That is, the first end of the first end frame <NUM> may be connected to the first end of the first side frame <NUM> by a fastening member, and the second end of the first end frame <NUM> may be connected to the first end of the second side frame <NUM> by the fastening member.

The second end frame <NUM> may be installed to connect the second ends of the first side frame <NUM> and the second side frame <NUM>. That is, the first end of the second end frame <NUM> may be connected to the second end of the first side frame <NUM> by the fastening member, and the second end of the second end frame <NUM> may be connected to the second end of the second side frame <NUM> by the fastening member.

The flexible printed circuit (FPC) <NUM>, which is electrically connected to the cell assembly <NUM> and configured to sense one or more properties of the battery cell <NUM>, may be installed on the side frame <NUM>.

The flexible printed circuit <NUM> may be connected to the battery cell <NUM> and the cell supervision circuit <NUM>, and may sense the voltage or the temperature of the battery cell <NUM> and may transmit the sensed results to the cell supervision circuit <NUM>.

The flexible printed circuit <NUM> may include a plurality of circuit lines <NUM> coated with an insulation film.

The circuit lines <NUM> of the flexible printed circuit <NUM> may be electrically connected to the cell supervision circuit <NUM> on a side of the cell assembly <NUM>.

The cell supervision circuit <NUM> may be referred to as a cell monitor circuit (CMC).

The cell supervision circuit <NUM> may receive a sensing signal of the battery cell <NUM> through the flexible printed circuit <NUM> and may confirm an abnormal operation state of the battery cell <NUM>.

The cell supervision circuit <NUM> is installed on one position or location of the cell assembly <NUM>, and in one or more embodiments, it may be installed on the second end frame <NUM> and it may be electrically connected to the flexible printed circuit <NUM>. The present disclosure is not limited to the cell supervision circuit <NUM> being installed on the position of the second end frame <NUM>, and in one or more embodiments the cell supervision circuit <NUM> may be installed on a different position such as on the first end frame <NUM>.

The cell supervision circuit <NUM> may be electrically connected to the flexible printed circuit <NUM> by the electrically conductive solder <NUM>.

In one or more embodiments, the cell supervision circuit <NUM> is electrically connected to the flexible printed circuit <NUM> by the electrically conductive solder <NUM> without using an additional terminal, thereby preventing disconnection of lines due to pressurized damages at the connected portion, and thus allowing a stable connection.

The electrically conductive solder <NUM> may function as a solder for electrically connecting the flexible printed circuit <NUM> and the cell supervision circuit <NUM>. In one or more embodiments, the electrically conductive solder <NUM> may work as a conductive glue. The electrically conductive solder <NUM> working as a solder will now be described in detail. The electrically conductive solder and the solder will use an identical reference numeral.

A conductive pad portion <NUM> for adhering the solder <NUM> may be formed on the flexible printed circuit <NUM>.

The conductive pad portion <NUM> is connected to the flexible printed circuit <NUM>, the solder <NUM> is adhered to the conductive pad portion <NUM>, and the conductive pad portion <NUM> may be electrically connected to the circuit lines <NUM> of the flexible printed circuit <NUM>. In one or more embodiments, the rechargeable battery pack <NUM> may include one conductive pad portion <NUM> for each of the circuit lines <NUM>.

The conductive pad portion <NUM> may have a bigger size (e.g., width) than the width of the circuit lines <NUM>, may protrude from an end of the circuit lines <NUM>, and may be electrically connected to the cell supervision circuit <NUM> by the solder <NUM>.

<FIG> shows a schematic perspective view of a flexible circuit substrate and a cell supervision circuit of <FIG> electrically connected by an electrically conductive solder, <FIG> shows a schematic perspective view of a state in which an electrically conductive solder of <FIG> is omitted, and <FIG> shows a state in which a conductive pad portion is formed while an electrically conductive solder of <FIG> is omitted.

Referring to <FIG>, in further detail, the conductive pad portion <NUM> may include a first expansion pad <NUM> protruding toward a first side of the circuit line <NUM> in a width direction, and a second expansion pad <NUM> protruding toward a second side of the circuit line <NUM> in the width direction. In one or more embodiments, the directions of the first side and the second side are opposite to each other.

The first expansion pad <NUM> may be connected to protrude from an end of the circuit line <NUM> while protruding in a first side direction with respect to a center of the end of the circuit line <NUM>.

The first expansion pad <NUM> is made of a same material as the circuit line <NUM> and protrudes in the first side direction while connected to the circuit line <NUM>, and may protrude in a curved (e.g., round) shape from the end of the circuit line <NUM>.

The second expansion pad <NUM> may protrude in an identical or similar shape to the first expansion pad <NUM> in a second side direction facing the first side direction from the end of the circuit line <NUM> (e.g., the first expansion pad <NUM> and the second expansion pad <NUM> may be symmetric).

The second expansion pad <NUM> is made of a same material as the circuit line <NUM> and protrudes in the second side direction while connected to the circuit line <NUM>, and may protrude in a curved (e.g., round) shape from the end of the circuit line <NUM>.

In one or more embodiments, the first expansion pad <NUM> and the second expansion pad <NUM> respectively protrude in a curved (e.g., round) shape in opposite directions, and may protrude while electrically connected to the end of the circuit line <NUM> and a round groove <NUM> may be formed between the first expansion pad <NUM> and the second expansion pad <NUM>.

The formation of the round groove <NUM> between the first expansion pad <NUM> and the second expansion pad <NUM> is configured to allow firm electrical connection by providing a sufficient space in which the solder <NUM> is filled and by increasing a surface area of a portion on which the solder <NUM> is applied.

In one or more embodiments, step sides 321a and 323a may be formed at respective ends of the first expansion pad <NUM> and the second expansion pad <NUM>. The formation of the step sides at the first expansion pad <NUM> and the second expansion pad <NUM> is to further increase the surface area in which the solder <NUM> is applied.

That is, an end of the first expansion pad <NUM> may be formed to be connected to an edge of the flexible printed circuit <NUM> along which the first step side 321a is formed.

An end of the second expansion pad <NUM> may be formed to be connected to the edge of the flexible printed circuit <NUM> along which the second step side 323a is formed.

Therefore, the solder <NUM> may be cured once the solder <NUM> has been sufficiently applied to the space formed by the first step side 321a and the second step side 323a and the space formed by the round groove <NUM>.

Hence, the solder <NUM> may be applied with the maximum applied area between the flexible printed circuit <NUM> and the cell supervision circuit <NUM> and may then be cured so the cell supervision circuit <NUM> may be connected to the flexible printed circuit <NUM> while their electrical connection is maximized.

The solder <NUM> may be applied as a cream solder to the first step side 321a, the second step side 323a, and the round groove <NUM>, it may be bonded by being cured by laser heat, and may then be electrically connected to the cell supervision circuit <NUM>.

However, without being limited to the cream solder type, the solder <NUM> may be applied to the first step side 321a, the second step side 323a, and the round groove <NUM> in a wire solder type, and may be cured by laser heat.

A plated layer may be formed on the surfaces of the first step side 321a and the second step side 323a so if the solder <NUM> is applied and cured, the electrical connection operation may be performed.

In one or more embodiments, a first spaced distance between an outer surface of the first expansion pad <NUM> and an outer surface of the second expansion pad <NUM> may be within a distance range of approximately <NUM> to approximately <NUM> times the spaced distance of one pair of adjacent circuit lines <NUM> from among a plurality of circuit lines.

In one or more embodiments, if a distance L1 between the one pair of adjacent circuit lines <NUM> is approximately <NUM>, a distance L2 between the outer surface of the first expansion pad <NUM> and the outer surface of the second expansion pad <NUM> may be approximately <NUM>.

In one or more embodiments, a distance L3 between a step of the first step side 321a and a step of the second step side 323a may be approximately <NUM>. In this embodiment, the area of the solder <NUM> applied between the first expansion pad <NUM> and the second expansion pad <NUM> may be approximately <NUM><NUM>.

In one or more embodiments, if the distance between one pair of the adjacent circuit lines <NUM> is approximately <NUM> while the step of the first step side 321a and the second step side 323a are not formed, the applied area of the solder <NUM> at the end of the circuit line is equal to or less than approximately <NUM><NUM>.

As described above, if the first expansion pad <NUM> and the second expansion pad <NUM> are formed at the end of the circuit line <NUM>, the applied area of the solder <NUM> may be maximized compared to an embodiment in which the first expansion pad <NUM> and the second expansion pad <NUM> are not formed.

Further, the surface of the solder <NUM> connecting the flexible printed circuit <NUM> and the cell supervision circuit <NUM> may be conformally coated.

The conformal coating <NUM> may be applied to cover the entire outer surface of the solder <NUM> cured for multiple times to connect the flexible printed circuit <NUM> and the cell supervision circuit <NUM>.

As described above, the rechargeable battery pack <NUM> according to a first embodiment of the present disclosure electrically connect the flexible printed circuit <NUM> and the cell supervision circuit <NUM> not by using an additional terminal (not shown) but by using the electrically conductive solder <NUM> such as the solder <NUM>, thereby preventing disconnection of lines which might otherwise occur due to compressed damages at the connection portion and thus allowing a stable connection.

<FIG> shows a schematic perspective view of a flexible circuit substrate electrically connected to a cell supervision circuit according to a second embodiment of the present disclosure by an electrically conductive solder, <FIG> shows a schematic perspective view of a state in which an electrically conductive solder of <FIG> is omitted, and <FIG> shows a schematic lateral view of a state in which an electrically conductive solder of <FIG> is omitted. The same reference numerals as those in <FIG> represent identical or similar members with the same or similar functions. No detailed descriptions on the same reference numerals will be provided.

As shown in <FIG>, a sub-pad portion <NUM> may be formed to be spaced from the conductive pad portion <NUM> in the respective circuit lines <NUM> formed on the flexible printed circuit <NUM> of the rechargeable battery pack according to a second embodiment of the present disclosure (e.g., each circuit line <NUM> may include a sub-pad portion <NUM> spaced apart from the conductive pad portion <NUM>).

The sub-pad portion <NUM> protrudes from the circuit line <NUM> from a position spaced from the conductive pad portion <NUM> by a predetermined distance, and a slot hole <NUM> may be formed sub-pad portion <NUM>.

The sub-pad portion <NUM> protrudes from the circuit line <NUM> at a position spaced from the conductive pad portion <NUM>, and the sub-pad portion <NUM> may protrude in a width direction of the circuit line <NUM>.

A slot hole <NUM> in a substantial slit shape (e.g., an elongated opening, such as an oval or elliptical shape) that is long in a length direction of the circuit line <NUM> may be formed at a center position of the sub-pad portion <NUM>. The slot hole <NUM> is shown to have a slit shape in the sub-pad portion <NUM>, and without being limited thereto, it may have a polygonal or round shape.

Therefore, the solder <NUM> may be inserted into the slot hole <NUM> of the sub-pad portion <NUM> to electrically connect the flexible printed circuit <NUM> and the cell supervision circuit <NUM> and thereby increase the strength of the electrical connection.

Claim 1:
A rechargeable battery pack comprising:
a cell assembly including at least one battery cell;
a side frame accommodating the cell assembly;
a flexible printed circuit electrically connected to the cell assembly and configured to sense at least one property of the battery cell; and
a cell supervision circuit electrically connected to the flexible printed circuit and on one side of the side frame,
wherein the flexible printed circuit is electrically connected to the cell supervision circuit by an electrically conductive solder without using an additional terminal.