Patent Description:
The present disclosure relates to a battery module having a structure allowing accurate temperature sensing, and a battery pack and a vehicle including the battery module, and more particularly, to a battery module having a structure allowing accurate temperature sensing, in which temperature sensors are installed at both longitudinal ends of a cell stack to allow accurate temperature sensing when sensing a temperature of the cell stack including battery cells having a long length compared to width, and a battery pack and a vehicle including the battery module.

It is very important to accurately measure the temperature of a battery cell located inside a battery. In particular, it is necessary to measure the maximum temperature of the battery cell. If the battery cell is overheated over a certain temperature, a problem may occur in a battery or a vehicle to which the battery is applied, which may greatly affect safety. Battery modules wherein the temperature of the battery cells is measured are disclosed in <CIT>, <CIT> and <CIT>.

In a battery module to which a typical battery cell having a ratio of length to width within a certain range is applied, there is no problem wherever a temperature sensor is located. However, in the case of a battery module to which a long cell having a ratio of length to width over a certain range is applied in order to increase the capacity of the battery module while increasing the utilization of space when installed in a vehicle, the temperature deviation may be increased according to the location of the temperature sensor along the longitudinal direction.

Thus, in the case of a battery module to which the long cell is applied, it is necessary to install the temperature sensor at a location where temperature may be measured more accurately. In addition, it is required to provide a scheme to install the temperature sensor to be more closely adhered to the cell stack for accurate temperature measurement without deviating from the existing battery module structure as much as possible so as to prevent an energy density loss or productivity deterioration of the battery module caused by the installation of the temperature sensor.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to preventing an energy density loss or productivity deterioration of a battery module while allowing more accurate measurement of temperature of battery cells included in the battery module.

In one aspect of the present disclosure, there is provided a battery module, comprising: a cell stack formed by stacking a plurality of battery cells; a bus bar frame assembly including a bus bar frame configured to cover one longitudinal end and the other longitudinal end of the cell stack and a plurality of bus bars fixed on the bus bar frame and electrically connected to the battery cells; and a FPCB assembly including a first FPCB extending along a longitudinal direction of the cell stack to cover at least a portion of an upper surface of the cell stack, a second FPCB extending from both longitudinal ends of the first FPCB and electrically connected to the bus bars, and a pair of temperature sensors mounted to both longitudinal ends of the first FPCB.

The battery cell may be a long cell having a ratio of length to width in the range of <NUM> to <NUM>.

The first FPCB has a temperature sensor placing portion formed by cutting a part of the first FPCB.

Both longitudinal ends of the temperature sensor placing portion are formed as fixed ends, and both widthwise ends of the temperature sensor placing portion are formed as free ends.

The battery module may further comprise an upper cover configured to cover an upper portion of the cell stack and the first FPCB.

A connection portion of the first FPCB and the second FPCB may be drawn out through a gap between the bus bar frame and the upper cover.

The battery cell may include an electrode assembly; a pair of electrode leads connected to the electrode assembly and extending in opposite directions along a longitudinal direction of the battery cell; and a cell case configured to accommodate the electrode assembly and sealed to expose the electrode lead to the outside.

The pair of electrode leads may be formed at locations biased downward from a center of the cell stack in a height direction.

The battery module may further comprise a connector mounted to the second FPCB and positioned in a space formed above the electrode lead due to biasing of the electrode lead.

In another aspect of the present disclosure, there are also provided a battery pack and a vehicle, which comprises the battery module according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, it is possible to prevent an energy density loss or productivity deterioration of a battery module while allowing more accurate measurement of temperature of battery cells included in the battery module.

First, the overall configuration of a battery module according to an embodiment of the present disclosure will be described with reference to <FIG>.

<FIG> is a perspective view showing a battery module according to an embodiment of the present disclosure, and <FIG> is a perspective view showing a cell stack applied to the battery module according to an embodiment of the present disclosure. Also, <FIG> is a plan view showing a battery cell applied to the battery module according to an embodiment of the present disclosure, and <FIG> is a perspective view showing the battery module according to an embodiment of the present disclosure, from which an upper cover is eliminated.

First, referring to <FIG>, a battery module according to an embodiment of the present disclosure may be implemented to include a cell stack <NUM>, a FPCB assembly <NUM>, a bus bar frame assembly <NUM>, an outer terminal <NUM> and an upper cover <NUM>.

The cell stack <NUM> includes a plurality of battery cells <NUM> stacked to face each other at wide surfaces thereof. The cell stack <NUM> may include at least one buffer pad P interposed at an outermost battery cell <NUM> and/or between adjacent battery cells <NUM>.

That is, the cell stack <NUM> may be inserted into a mono frame (not shown) in a state of being coupled with the FPCB assembly <NUM>, the bus bar frame assembly <NUM>, the outer terminal <NUM> and the upper cover <NUM>. At this time, in order to insert the cell stack <NUM> easily while securing a maximum volume of the cell stack <NUM>, the buffer pad P made of an elastic material such as a sponge may be additionally applied.

A pouch-type battery cell may be applied as the battery cell <NUM>. Referring to <FIG>, the pouch-type battery cell <NUM> includes an electrode assembly (not shown), a pair of electrode leads <NUM> and a cell case <NUM>.

Although not shown in the drawings, the electrode assembly has a form in which separators are interposed between positive electrode plates and negative electrode plates that are repeatedly stacked alternately, and separators are preferably positioned at both outermost sides for insulation, respectively.

The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer coated on one side of the positive electrode current collector, and a positive electrode uncoated region not coated with a positive electrode active material is formed at one side end of the positive electrode plate. The positive electrode uncoated region functions as a positive electrode tab.

The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer coated on one surface or both sides of the negative electrode current collector, and a negative electrode uncoated region not coated with a negative electrode active material is formed at one side end of the negative electrode plate. The negative electrode uncoated region functions as a negative electrode tab.

In addition, the separator is interposed between the positive electrode plate and the negative electrode plate to prevent electrode plates having different polarities from directly contacting each other. The separator may be made of a porous material so that ions may be moved using the electrolyte as a medium between the positive electrode plate and the negative electrode plate.

The pair of electrode leads <NUM> are connected to the positive electrode tab (not shown) and the negative electrode tab (not shown), respectively, and are drawn out of the cell case <NUM>. The pair of electrode leads <NUM> are drawn out at one longitudinal side and the other longitudinal side of the battery cell <NUM>, respectively. That is, the battery cell <NUM> applied to the present disclosure corresponds to a bidirectional draw-out battery cell in which the positive electrode lead and the negative electrode lead are drawn in opposite directions.

In addition, the pair of electrode leads <NUM> are positioned to be biased to one side from a center of the battery cell <NUM> in a width direction (the Z-axis direction of <FIG>). Specifically, the pair of electrode leads <NUM> are positioned to be biased to one side from the center of the battery cell <NUM> in the width direction, preferably to be biased downward along the height direction (the Z-axis direction of <FIG>) of the cell stack <NUM>.

If the pair of electrode leads <NUM> are positioned to be biased to one side from the center of the battery cell <NUM> in the width direction as described above, it is possible to give a space for installation of a connector <NUM> (see <FIG>), explained later, and the outer terminal (see <FIG>) so that the energy density of the battery module is improved. The increase in energy density due to the structure in which the electrode lead <NUM> is installed to be biased will be described in detail later.

The cell case <NUM> includes two regions, namely an accommodation portion accommodating the electrode assembly and a sealing portion extending in a circumferential direction of the accommodation portion and thermally fused in a state where the electrode lead <NUM> is drawn out to seal the cell case <NUM>.

Although not shown in the figures, the cell case <NUM> is sealed by affixing and thermally fusing edge portions of an upper case and a lower case made of a multi-layered pouch film in which a resin layer, a metal layer and a resin layer are stacked in order.

In the sealing portion, a terrace portion 112a corresponding to a region located in the direction in which the electrode lead <NUM> is drawn out has a tapered shape such that both sides of the terrace portion 112a are cut so that the width thereof is gradually reduced along the drawing direction of the electrode lead <NUM>. As described above, if the width of the terrace portion 112a is gradually reduced toward the outer side of the battery cell <NUM>, the electrode lead <NUM> may be disposed to be biased, and the energy density of the battery module may be improved.

Meanwhile, the battery cell <NUM> applied to the present disclosure is a long cell where a ratio of length (L) to width (W) is about <NUM> or more and <NUM> or less. In the battery module according to the present disclosure, if the long cell type battery cell <NUM> is employed, it is possible to improve the capacity of the battery while minimizing the increase in the height of the battery module, which makes it easy to install the battery module at a lower part of a seat or a trunk of a vehicle.

Next, the FPCB assembly <NUM> will be described in detail with reference to <FIG> along with <FIG>.

<FIG> is a perspective view showing a FPCB assembly not according to the invention applied to the battery module , <FIG> is a partially enlarged view showing a portion of the FPCB assembly not according to the invention depicted in <FIG>, and <FIG> is a diagram showing that the shape of the temperature sensor placing portion according to the present invention is partially modified in the structure of the FPCB assembly depicted in <FIG>.

Referring to <FIG>, the FPCB assembly <NUM> may be implemented to include a first FPCB <NUM>, a second FPCB <NUM>, a temperature sensor <NUM> and a connector <NUM>. In the present disclosure, the first FPCB <NUM> and the second FPCB <NUM> are described as components distinguished from each other, but the first FPCB <NUM> and the second FPCB <NUM> may be a single integrated flexible printed circuit board (FPCB). That is, the first FPCB <NUM> and the second FPCB <NUM> are just elements that are distinguished according to positions where they are disposed.

The first FPCB <NUM> extends along the longitudinal direction of the cell stack <NUM> (the Y-axis direction of <FIG> and <FIG>) to cover at least a portion of the upper surface of the cell stack <NUM>. Both longitudinal ends of the first FPCB <NUM> are provided with a temperature sensor placing portion <NUM> formed by cutting a portion of the first FPCB <NUM>.

The temperature sensor <NUM> is mounted to the upper surface of the temperature sensor placing portion <NUM>, whereby the temperature sensor <NUM> is installed at positions corresponding to both ends of the cell stack <NUM> in the longitudinal direction (the Y-axis of <FIG>). In addition, the temperature sensor placing portion <NUM> is located at the center of the cell stack <NUM> in the width direction (the X-axis of <FIG>). Accordingly, the temperature sensor <NUM> is installed at a position corresponding to the center of the cell stack <NUM> in the width direction.

The position where the temperature sensor placing portion <NUM> is formed is selected to sense a temperature of a portion with the highest temperature in the cell stack <NUM>. The FPCB assembly <NUM> may be connected to a control device that may control charging and discharging of the battery module, such as a battery management system (BMS). If the temperature of the battery module rises above a reference value, in order to ensure safety in use of the battery module, it is preferable to measure the temperature at a location with the highest temperature to control charging and discharging.

Thus, in the longitudinal direction of the cell stack <NUM> (the Y-axis direction of <FIG>), both longitudinal ends closest to the electrode lead <NUM> become optimal positions, and in the width direction of the cell stack <NUM> (the X-axis direction of <FIG>), the center where heat dissipation is most difficult becomes an optimal position.

As shown in <FIG>, the temperature sensor placing portion <NUM> is formed by cutting a part of the first FPCB <NUM>, and one of both longitudinal ends of the temperature sensor placing portion <NUM> is formed as a fixed end and the other is formed as a free end. In addition, both widthwise ends of the temperature sensor placing portion <NUM> are formed as free ends by cutting.

By doing so, the temperature sensor placing portion <NUM> may move up and down freely despite the characteristics of the FPCB having a certain degree of stiffness. Accordingly, the temperature sensor <NUM> mounted to the temperature sensor placing portion <NUM> is indirectly adhered to the cell stack <NUM> through the temperature sensor placing portion <NUM>, thereby accurately measuring the temperature of the cell stack <NUM>.

Meanwhile, referring to <FIG>, both widthwise ends of the temperature sensor placing portion <NUM> are formed as free ends and both longitudinal ends thereof are formed as fixed ends by cutting. If both longitudinal ends of the temperature sensor placing portion <NUM> are formed as fixed ends as above, as shown in <FIG>, the risk of damage such as tearing of the temperature sensor placing portion <NUM> may be reduced compared to the case where only one longitudinal end is formed as a fixed end.

Next, the second FPCB <NUM> and the connector <NUM> applied to the present disclosure will be described in detail with reference to <FIG> and <FIG> along with <FIG>.

<FIG> is a partially enlarged view showing the battery module depicted in <FIG>, and <FIG> is a diagram showing the battery module depicted in <FIG>, observed from one side.

Referring to <FIG> and <FIG> along with <FIG>, the second FPCB <NUM> is provided in a pair, and the second FPCBs <NUM> extend from both longitudinal ends of the first FPCB <NUM> and are electrically connected to a bus bar <NUM>, explained later, respectively. That is, the second FPCB <NUM> has a plurality of connection terminals <NUM> formed at several branched ends, and the plurality of connection terminals <NUM> are connected to a plurality of bus bar <NUM>, explained later.

Meanwhile, the connector <NUM> is mounted on the second FPCB <NUM>, and the connector <NUM> is electrically connected to the connection terminal <NUM> through the FPCB. As described above, a control device (not shown) such as BMS is connected to the connector <NUM>, and the control device receives information about a voltage of the battery cell <NUM> measured through the bus bar <NUM> and the connection terminal <NUM>, information about a temperature of the cell stack <NUM> measured through the temperature sensor <NUM>, or the like, and controls charging and discharging of the battery module with reference to the information.

Meanwhile, as shown in <FIG>, the connector <NUM> mounted on the second FPCB <NUM> faces a front surface (a surface parallel to the X-Z plane of <FIG> and <FIG>) of the cell stack <NUM> but is installed in a space formed above the electrode lead <NUM> due to biasing of the electrode lead <NUM>. That is, the connector <NUM> is installed to face an upper portion of the front surface of the cell stack <NUM>.

As such, the connector <NUM> is installed in the space provided due to the structure in which the electrode lead <NUM> is installed to be biased, which minimizes the overall volume increase of the battery module caused by the installation of the connector <NUM>, thereby improving energy density.

Subsequently, the bus bar frame assembly <NUM> and the outer terminal <NUM> applied to the present disclosure will be described in detail with reference to <FIG>.

Referring to <FIG>, the bus bar frame assembly <NUM> may be implemented to include a bus bar frame <NUM> configured to cover one longitudinal end and the other longitudinal end of the cell stack <NUM> and a plurality of bus bars <NUM> fixed on the bus bar frame <NUM> and electrically connected to the battery cells <NUM>.

The bus bar frame <NUM>, for example, may be made of an insulating material such as resin, and includes a bus bar placing portion <NUM> formed to protrude at a position corresponding to electrode leads <NUM> of the battery cell <NUM>. The bus bar placing portion <NUM> is formed at a position biased downward from the center of the cell stack <NUM> in the height direction (the Z-axis direction of <FIG>), like the electrode lead <NUM>. The biasing of the bus bar placing portion <NUM> is to secure a space for installing components, similar to the biasing of the electrode lead <NUM>.

The bus bar placing portion <NUM> has a plurality of lead slits S formed at positions corresponding to the electrode leads <NUM>. Through the lead slits S, the electrode leads <NUM> are drawn out of the bus bar frame assembly <NUM>, and the drawn electrode leads <NUM> are bent and fixed by welding or the like on the bus bar <NUM>.

The outer terminal <NUM> is provided in a pair, and the outer terminals <NUM> are respectively connected to the bus bars <NUM> located at outsides of the both sides of the cell stack <NUM> in the width direction (the X-axis direction of <FIG>).

Like the connector <NUM> described above, the outer terminal <NUM> is located in the space formed above the electrode lead <NUM> and the bus bar placing portion <NUM> due to the biasing of the electrode lead <NUM>. The location where the outer terminal <NUM> is formed may minimize the volume of the battery module increased by installing the outer terminal <NUM> since it utilizes the space formed by the biased installation of the electrode lead <NUM>.

Next, the upper cover <NUM> will be described with reference to <FIG> and <FIG>.

Referring to <FIG> and <FIG>, the upper cover <NUM> corresponds to a component that covers an upper surface of the cell stack <NUM> (a surface parallel to the X-Y plane of <FIG> and <FIG>) and the first FPCB <NUM>. The upper cover <NUM> is hinged to the pair of bus bar frames <NUM>, respectively, and a gap is formed at a location corresponding to the connection portion of the first FPCB <NUM> and the second FPCB <NUM>, so that the connection portion of the first FPCB <NUM> and the second FPCB <NUM> is drawn out of the upper cover <NUM> through the gap.

As described above, in the battery module according to the present disclosure, a long cell is applied as each of the battery cells <NUM> included in the cell stack <NUM>, and accordingly, the temperature deviation tends that to be large along the longitudinal direction of the cell stack <NUM>.

In the battery module according to the present disclosure, in consideration of the temperature deviation, the temperature sensors <NUM> are installed at both longitudinal ends of the cell stack <NUM> to allow effective temperature sensing. In addition, in the battery module according to the present disclosure, the adhesion between the temperature sensor <NUM> and the cell stack <NUM> is maximized by providing the temperature sensor placing portions <NUM> formed by cutting a part of the first FPCB <NUM> so that the temperature sensor <NUM> is placed on the temperature sensor placing portions <NUM>.

Claim 1:
A battery module, comprising:
a cell stack (<NUM>) formed by stacking a plurality of battery cells (<NUM>);
a bus bar frame assembly (<NUM>) including a bus bar frame (<NUM>) configured to cover one longitudinal end and the other longitudinal end of the cell stack (<NUM>) and a plurality of bus bars (<NUM>) fixed on the bus bar frame (<NUM>) and electrically connected to the battery cells (<NUM>); and
a FPCB assembly (<NUM>) including a first FPCB (<NUM>) extending along a longitudinal direction of the cell stack (<NUM>) to cover at least a portion of an upper surface of the cell stack (<NUM>), a second FPCB (<NUM>) extending from both longitudinal ends of the first FPCB (<NUM>) and electrically connected to the bus bars (<NUM>), and a pair of temperature sensors (<NUM>) mounted to both longitudinal ends of the first FPCB (<NUM>),
wherein the first FPCB (<NUM>) has a temperature sensor placing portion (<NUM>) formed by cutting a part of the first FPCB (<NUM>), and
wherein both longitudinal ends of the temperature sensor placing portion (<NUM>) are formed as fixed ends, and both widthwise ends of the temperature sensor placing portion (<NUM>) are formed as free ends.