Patent Description:
A secondary battery has attracted much attention as an energy source in various products such as a mobile device and an electric vehicle. The secondary battery is a potent energy resource that can replace the use of existing products using fossil fuels, and is in the spotlight as an environment-friendly energy source because it does not generate by-products due to energy use.

Recently, along with a continuous rise of the necessity for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series/parallel.

Meanwhile, when a plurality of battery cells are connected in series/parallel to configure a battery pack, a method of configuring a battery module composed of at least one battery cell and then adding other components to at least one battery module to configure a battery pack is common. Such a battery pack can be mainly used as an energy source for an electric vehicle.

When designing such a battery module, it has been developed by pressing the battery cells at a constant pressure and thus, the battery cells are swelled in the process of repeating charging and discharging. However, as the battery cells are swelling, there is a concern that swelling may occur to such an extent as to push out the surrounding module frame and battery pack case.

Therefore, if the pressure of battery cells can be measured, action can be taken through the pressure measured before the appearance of the battery module or the battery pack is deformed, thereby securing the safety of the battery module and the battery pack. At this time, the swelling pressure of the battery cells can be measured by using a pressure sensor, but in the case of FSR (Force-Sensing Resistor) sensor, which has previously been often used as a pressure sensor, there is a problem it is small in size and thus dose not measure all the swelling pressures generated on the entire surface of the battery cells.

Further, when the size of the FSR sensor is made larger in compliance with the surface size of the battery cells, a spacer that supports an upper plate and a lower plate between the upper plate and the lower plate no longer supports the upper plate and the lower plate, which causes a problem that the swelling pressure of the battery cells are not accurately measured.

Examples of background art can be found in <CIT> and <CIT>.

It is an object of the present disclosure to provide an apparatus for measuring a pressure of battery cells, which can accurately measure a swelling pressure of battery cells.

The objects of the present disclosure are not limited to the aforementioned objects, and other objects which are not described herein should be clearly understood by those skilled in the art from the following detailed description.

In order to achieve the above objects, an apparatus for measuring a pressure of battery cells according to the independent claim <NUM> is provided.

The apparatus may include a third plate formed so as to be in contact with the battery cell in an opposite direction of the pressure sensor based on the battery cell.

The first, second, and third plates may be coupled to each other via a fixing member.

The first, second, and third plates may be formed wider than the pressure sensor and the battery cell, and the fixing member may be coupled to the first, second, and third plates on the outside of the pressure sensor and the battery cell.

The first, second, and third plates may be formed in a size that covers the pressure sensor and the battery cell.

At least one of the first, second, and third plates may be formed in a thickness of <NUM>.

The first, second, and third plates may include aluminum.

The pressure sensor may include a plurality of pressure measuring units, a connection unit that connects the plurality of pressure measuring units to each other, and an output unit that is connected to the connection unit, and sums up the pressure values measured via the pressure measuring unit and outputs the result.

The output unit may separately output the pressure value measured for each column or each row of the pressure measuring unit.

The apparatus for measuring a pressure of battery cells according to an embodiment of the present invention can accurately measure the swelling pressure while minimizing the imbalance of the electrolytic solution through the first plate arranged so as to be in contact with the battery cell and the pressure sensor.

It should be appreciated that the exemplary embodiments, which will be described below, are illustratively described to help understand the present disclosure, and the present invention may be variously modified to be carried out differently from the exemplary embodiments described herein. However, in the description of the present disclosure, the specific descriptions and illustrations of publicly known functions or constituent elements will be omitted when it is determined that the specific descriptions and illustrations may unnecessarily obscure the subject matter of the present disclosure. In addition, in order to help understand the present disclosure, the accompanying drawings are not illustrated based on actual scales, but parts of the constituent elements may be exaggerated in size.

As used herein, terms such as first, second, and the like may be used to describe various components, and the components are not limited by the terms. The terms are used only to discriminate one component from another component.

Further, the terms used herein are used only to describe specific exemplary embodiments, and are not intended to limit the scope of the present invention. A singular expression includes a plural expression unless they have definitely opposite meanings in the context. It should be understood that the terms "comprise", "include", and "have" as used herein are intended to designate the presence of stated features, numbers, steps, constitutional elements, or combinations thereof, but it should be understood that they do not preclude a possibility of existence or addition of one or more other features, numbers, steps, constitutional elements, or combinations thereof.

Now, a battery cell and a pressure sensor attached to the battery cell according to an embodiment of the present invention will be described with reference to <FIG>.

<FIG> is an exploded perspective view illustrating a battery module including battery cells. <FIG> is a view illustrating a battery cell of <FIG>. <FIG> is a view illustrating a state in which a pressure sensor according to an embodiment of the present invention is formed on the surface of the cell body of <FIG>.

Referring to <FIG>, the apparatus for measuring a pressure of battery cells according to an embodiment of the present invention includes a pressure sensor <NUM> configured to measure the pressure of battery cells <NUM> stacked inside a battery module <NUM>. The pressure sensor <NUM> includes a plurality of pressure measuring units <NUM>, a connection unit <NUM> configured to connect the plurality of pressure measuring units <NUM> to each other, and an output unit <NUM> connected to the connection unit <NUM> and configured to output the pressure values measured via the pressure measuring units <NUM>. The plurality of pressure measuring units <NUM> are arranged on the surfaces of the battery cells <NUM> to measure the pressures of the battery cells <NUM>.

The battery cell <NUM> is a secondary battery, and may be configured of a pouch type secondary battery. The battery cells <NUM> may be formed of a plurality of battery cells and the plurality of the battery cells may be stacked together so as to be electrically connected to each other, thereby forming the battery cell stack <NUM>.

A module frame <NUM> can house the battery cell stack <NUM> and a busbar frame assembly <NUM> to protect electronic components constituting the battery module from the outside.

The busbar frame assembly <NUM> may include busbar frames <NUM> configured to cover front and rear surfaces of the battery cell stack <NUM>, and an upper plate <NUM> configured to connect two busbar frames <NUM> on an upper surface of the battery cell stack <NUM>. The busbar frame <NUM> can electrically connect an electrode lead formed in the battery cell <NUM> and the busbar through a busbar mounted on the busbar frame <NUM>. A connection unit (not illustrated) may be formed at a lower side of the upper plate <NUM> to electrically connect the busbar frames <NUM> formed at both ends of the battery cell stack <NUM>. The busbar frame assembly <NUM> may be coupled to the front and rear surfaces and the upper surface of the battery cell stack <NUM>.

End plates <NUM> may be disposed so as to cover the front and rear surfaces of the battery cell stack <NUM>. The end plates <NUM> may be coupled by welding to edge portions of the module frame <NUM>.

The battery cells <NUM> disposed inside the battery module <NUM> occurs a swelling phenomenon, in which the volumes of the battery cells <NUM> expand while repeating charging and discharging, and due to the swelling of the battery cells, deformation may be occurred in the battery module and a battery pack on which the battery module is mounted. Therefore, before the battery module and the battery pack are deformed, it is possible to measure a swelling pressure and take a pretreatment based on the measured pressure value.

According to the present embodiment, the plurality of pressure measuring units <NUM> are arranged in rectangular grids on the surface of the battery cells <NUM>, and the pressure measuring units <NUM> are connected to each other by the connection unit <NUM> to cover all ranges of the surfaces of the battery cells. Further, because the connection unit <NUM> is connected to one output unit <NUM>, whereby the pressure values measured through the plurality of the pressure measuring units <NUM> can be outputted by summing up into one output value through the output unit <NUM> formed of one, so that the swelling pressure can be grasped more easily.

Further, the output unit <NUM> can separately output the values measured for each column or each row of the pressure measuring unit <NUM>. Thereby, the pressure values formed so as to be different for each position on the surface of the battery cell <NUM> can be measured separately.

Referring to <FIG>, the battery cell <NUM> may include a cell body <NUM>, a cell terrace <NUM>, and an electrode lead <NUM>, and the plurality of pressure measuring units <NUM> may be arranged on the body surface of the cell body <NUM>.

Each of the plurality of pressure measuring units <NUM> may include a current input unit <NUM> and a current output unit <NUM>, and the connection unit <NUM> may include a current input side connection unit <NUM> for connecting the current input units <NUM>, and a current output side connection unit <NUM> for connecting the current output units <NUM>. Here, the output unit <NUM> may be connected to the current input side connection unit <NUM> and the current output side connection unit <NUM> to output the pressure value measured from the plurality of pressure measuring units.

The plurality of pressure measuring units <NUM> may be formed in a circular shape having a pattern. In more detail, referring to <FIG>, the current input side connection unit <NUM> and the current output side connection unit <NUM> may form an outskirt of the pressure measuring unit <NUM> of a circular shape and sensing units extending from the current input side connection unit <NUM> and the current output side connection unit <NUM> may form a pattern of the interior of a circular shape.

Below, an apparatus for measuring a pressure of battery cells according to an embodiment of the present invention will be described with reference to <FIG>.

<FIG> is a view illustrating a state in which a sensor mark is formed on the surface of a cell during pressure measurement according to <FIG>. <FIG> is a view illustrating the state of the apparatus for measuring a pressure of battery cells according to one embodiment of the present invention. <FIG> is a view illustrating a plurality of holes formed in the second plate according to one embodiment of the present invention.

Referring to <FIG>, the apparatus for measuring a pressure of battery cells according to the present invention includes a battery cell <NUM>, a pressure sensor <NUM> configured to measure the surface pressure of the battery cell <NUM>, and a first plate arranged between the battery cell <NUM> and the pressure sensor <NUM> so as to be in contact with the battery cell <NUM> and the pressure sensor <NUM>.

When the surface pressure of the battery cell <NUM> is measured only with the pressure sensor <NUM>, a sensor mark M due to the shape of the pressure measuring unit <NUM> may be formed on the surface of the cell body <NUM> as shown in <FIG>. The pressure measuring unit <NUM> has a structure in which the pressure is measured while the upper end part is pressed downward and the resistance value changes due to a change of a minute current, and the pressure can be measured by allowing the pressure measuring unit <NUM> to press the surface of the cell body <NUM>, whereby a sensor mark M can be generated on the pressed surface of the cell body <NUM>. Due to the sensor mark M generated at this time, the electrolytic solution inside the battery cell <NUM> may spread in an unbalanced manner, which results in deterioration of the performance of the battery cell <NUM>.

In this regard, according to the present embodiment, the first plate <NUM> is arranged between the battery cell <NUM> and the pressure sensor <NUM> to prevent a sensor mark M from being occurred on the surface of the cell body <NUM> of the battery cell <NUM>, thereby minimizing the imbalance of the electrolytic solution inside the battery cell <NUM> due to the pressure sensor <NUM>. In addition, the accuracy of sensing can be improved by allowing the surface unit pressure measurement of the cell body <NUM> to be performed by the first plate <NUM>.

According to the claimed invention, the apparatus further includes a second plate <NUM> formed so as to be in contact with the pressure sensor <NUM> in an opposite direction of the battery cell <NUM> based on the pressure sensor <NUM>. As the second plate <NUM> is covered on the upper surface of the pressure sensor <NUM>, the first and second plates <NUM> and <NUM> are arranged on the upper and lower sides of the pressure sensor <NUM>. Thereby, even if one side of the pressure sensor <NUM> is more pressed than the other side, the first and second plates <NUM> and <NUM> evenly fix the entire surface of the pressure sensor <NUM> back and forth, so that the surface pressure of the cell body <NUM> can be uniformly measured via the pressure sensor <NUM>.

Referring to <FIG>, the second plate <NUM> includes a plurality of holes 700a formed at positions corresponding to each of the plurality of pressure measuring units <NUM>. Air may fill inside the pressure measuring units <NUM> formed in a circular pattern, and the first and second plates <NUM> and <NUM> are arranged on the upper and lower sides of the pressure sensor <NUM>, and are stacked between the first and second plates <NUM> and <NUM> in a state where cold air cannot escape inside the pressure measuring unit <NUM>, and accurate pressure measurement may not be achieved. Thus, according to the present embodiment, a plurality of holes 700a are formed at positions corresponding to each of the plurality of pressure measuring units <NUM>, and the air generated inside the pressure measuring unit <NUM> can be discharged to the outside to measure the surface pressure of the battery cell <NUM> more accurately.

According to the present embodiment, the apparatus may further include a third plate <NUM> formed so as to be in contact with the battery cell <NUM> in an opposite direction of the pressure sensor <NUM> based on the battery cell <NUM>. The third plate <NUM> is arranged on the opposite side of the pressure sensor <NUM> mounted on one surface of the battery cell <NUM>, and fixes the battery cell <NUM> during pressure measurement through the pressure sensor <NUM> to perform more accurate pressure measurement.

Referring to <FIG>, in order for the pressure sensor <NUM> to accurately measure the pressure of the battery cell <NUM>, the first, second, and third plates <NUM>, <NUM> and <NUM> can be coupled to each other via the fixing member <NUM>. The first, second, and third plates <NUM>, <NUM> and <NUM> may be formed in a size that covers the pressure sensor <NUM> and the battery cell <NUM>. At this time, the first, second, and third plates <NUM>, <NUM> and <NUM> may be formed wider than the pressure sensor <NUM> and the battery cell <NUM>. In this case, the fixing member <NUM> can be coupled to the first, second, and third plates <NUM>, <NUM> and <NUM> on the outside of the pressure sensor <NUM> and the battery cell <NUM>.

According to the present embodiment, at least one of the first, second, and third plates <NUM>, <NUM> and <NUM> may be formed in a thickness of <NUM>. Further, the first, second, and third plates <NUM>, <NUM> and <NUM> may include aluminum. The plates are made of a material that makes pressure transmission excellent while being lightweight, which can improve the accuracy of pressure measurement of the battery cell.

The method for measuring the pressure of battery cells according to the present embodiment includes a step of applying a pressure to a pressure sensor <NUM> while a battery cell <NUM> is swelled, a step of transferring sensing information of the pressure sensor <NUM> to a BMS (battery management system), and a step of transferring the sensing information from a MCU (micro controller unit) inside the BMS to a user or an ECU (electric control unit). In more detail, in a battery cell for a vehicle, sensing information from the MCU may be transferred to the ECU of the vehicle, and in a battery cell for an ESS (energy storage system), sensing information from the MCU may be transferred to a user.

Swelling information measured from the pressure sensor <NUM> is transferred to a user so that the user can take a pretreatment on a product before the battery module and the battery pack are deformed.

According to the present embodiment, in the step of transferring sensing information to a BMS, a warning signal may be transmitted when a resistance value of the pressure sensor <NUM> is <NUM>,<NUM> Ohm or less. Further, a danger signal may be transmitted when a resistance value of the pressure sensor <NUM> is <NUM>,<NUM> Ohm or less. This means that the pressure acts on the pressure sensor <NUM> more strongly as the resistance value decreases. Further, as the resistance value of the pressure sensor <NUM> decreases, the type of the signal depending on the swelling becomes different, so that a user can immediately recognize the danger level depending on the level of swelling according to the type of the signal in advance.

In order to more exactly perform signal transmission of the pressure sensor, the method for measuring the pressure of the battery cell may further include a step of setting a resistance value of the pressure sensor to be infinite before the step of applying the pressure to the pressure sensor <NUM> while the battery cell <NUM> is swelled. When the resistance value is infinity, it means that no pressure is applied, and as the resistance value decreases, it means that the pressure is increasingly acting on the pressure sensor <NUM>.

Claim 1:
An apparatus for measuring a pressure of battery cells (<NUM>), the apparatus comprising:
a battery cell (<NUM>);
a pressure sensor (<NUM>) configured to measure the surface pressure of the battery cell (<NUM>);
a first plate (<NUM>) arranged between the battery cell (<NUM>) and the pressure sensor (<NUM>) so as to be in contact with the battery cell (<NUM>) and the pressure sensor (<NUM>), and
a second plate (<NUM>) formed so as to be in contact with the pressure sensor (<NUM>) in an opposite direction of the battery cell (<NUM>) based on the pressure sensor (<NUM>),
wherein the pressure sensor (<NUM>) comprises a plurality of pressure measuring units (<NUM>),
characterized in that the second plate (<NUM>) comprises a plurality of holes (700a) formed at positions corresponding to each of the plurality of pressure measuring units (<NUM>) configured to allow air generated inside the pressure measuring units (<NUM>) to be discharged.