Patent Description:
The present invention relates to a battery module and a manufacturing method thereof, and more particularly, to a battery module and a manufacturing method thereof, capable of easily monitoring resin injection into the battery module.

With technology development and a demand for mobile devices, demand for rechargeable batteries as an energy source has been rapidly increasing. Accordingly, much research on rechargeable batteries that may meet various demands have been conducted.

A rechargeable battery has attracted considerable attention as an energy source for power-driven devices such as an electric bicycle, an electric vehicle, and a hybrid electric vehicle, as well as an energy source for mobile devices such as a cellular phone, a digital camera, and a laptop computer.

A small-sized device such as a cellular phone or a camera uses a small-sized battery pack in which one battery cell is packed, but a mid- or large-sized device such as a laptop computer or an electric vehicle uses a mid- or large-sized battery pack in which a plurality of battery modules including two or more battery cells connected to each other in parallel and/or in series are packed. Therefore, a number of battery cells included in the battery pack may be variously set depending on a required output voltage, or charge and discharge capacity.

On the other hand, when a battery pack is configured by connecting a plurality of battery cells in series or parallel, a usual method is a method of configuring a battery pack by first configuring a battery module made of at least one battery cell and adding other components using the at least one battery module.

In the case of such a battery module, importance of a technique capable of efficiently cooling heat generated in a battery cell is gradually increasing as required battery capacity increases. To this end, a structure capable of improving thermal conductivity by applying a resin for heat dissipation to an interior of a case in the battery module is introduced.

However, when a resin is injected through an injection port from the battery module into the case, it is difficult to determine an injection amount, and thus when insufficient resin is injected, the resin is not evenly distributed inside the case, or too much resin is injected and unnecessary waste occurs, and a separate process is required to remove the wasted resin.

The present invention has been made in an effort to provide a battery module and a manufacturing method thereof, capable of preventing a resin from leaking through a detection hole or the like and effectively monitoring a state of an injected resin within the module.

However, the problem to be solved by the exemplary embodiments of the present invention is not limited to the above-described problem, and can be variously extended within the scope of the claims.

The present invention provides a battery module including: a module frame configured to include a lower plate and a pair of side walls constituting an internal space; a battery cell stack disposed in the internal space of the module frame to include a plurality of battery cells that are stacked to be adjacent to each other side by side; and a resin layer disposed between the lower plate and the battery cell stack wherein the resin layer includes a detection agent selected from a contrast agent and a coloring material.

The resin layer may include a thermally conductive resin.

The contrast agent may have a particle form.

The coloring material may be pigment particles.

The at least one transparent window may be spaced apart from the at least one detection hole along a longitudinal direction of the lower plate.

The resin layer may contact the transparent tape.

An exemplary embodiment of the present invention provides a manufacturing method of a battery module, including: accommodating a battery cell stack in which a plurality of battery cells are stacked to be adjacent to each other side by side in a module frame; injecting a resin composition containing a detection agent between the battery cell stack and a lower plate of the module frame through at least one injection hole formed in the lower plate; and stopping injection of the resin composition through the injection hole when the resin composition is evenly diffused between the battery cell stack and the lower plate by monitoring a flow of the resin composition containing the detection agent.

The detection agent is a contrast agent, and the monitoring may be performed by computer tomography (CT).

The detection agent may be a coloring material, and the lower plate may include at least one transparent window that is spaced from the at least one injection hole.

The monitoring may be performed by monitoring a color change of the transparent window using a color difference meter.

An exemplary embodiment of the present invention provides a battery pack including: the at least one battery module; and a pack case for packaging the at least one battery module.

An exemplary embodiment of the present invention provides a device including the at least one battery pack.

According to the exemplary embodiments, it is possible to provide a battery module and a manufacturing method thereof, capable of preventing a resin from leaking through a detection hole or the like and effectively monitoring a state of an injected resin within the module.

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art wherein realize, the described embodiments may be modified in various different ways, all without departing from the scope of the claims.

To clearly describe the present invention, parts that are irrelevant to the description are omitted, and like numerals refer to like or similar constituent elements throughout the specification.

Further, since sizes and thicknesses of constituent members shown in the accompanying drawings are arbitrarily given for better understanding and ease of description, the present invention is not limited to the illustrated sizes and thicknesses. In the drawings, the thicknesses of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, for better understanding and ease of description, the thicknesses of some layers and areas are exaggerated.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Further, in the specification, the word "on" or "above" means positioned on or below the object portion, and does not necessarily mean positioned on the upper side of the object portion based on a gravitational direction.

Further, in the specification, the phrase "in a plan view" means when an object portion is viewed from above, and the phrase "in a cross-sectional view" means when a cross-section taken by vertically cutting an object portion is viewed from the side.

<FIG> illustrates a cross-section of a battery module according to an exemplary embodiment of the present invention, <FIG> illustrates a state viewed from a side of a lower plate in a battery module according to an exemplary embodiment of the present invention, and <FIG> illustrates a view for describing a flow of a resin according to an example of the present invention.

Referring to <FIG>, the battery module <NUM> according to the exemplary embodiment of the present invention is configured to include a battery cell stack <NUM> in which a plurality of battery cells <NUM> are stacked to be adjacent to each other side by side and a module frame <NUM> in which the battery cell stack <NUM> is accommodated.

The battery cell stack <NUM> is an aggregate of rechargeable batteries including a plurality of battery cells <NUM>. The battery cell stack <NUM> may include the plurality of battery cells <NUM>, and each of the battery cells includes an electrode lead (not illustrated). The battery cells <NUM> may be stacked and connected using the electrode leads to constitute the battery cell stack <NUM>. The battery cell <NUM> may be a pouch-type battery cell having a plate-like shape, but the present invention is not limited in addition. The electrode lead is a positive electrode lead or a negative electrode lead, and an end portion of the electrode lead of each of the battery cells <NUM> may be bent in a direction such that it may contact ends of the electrode leads of the adjacent battery cells <NUM>. The two electrode leads in contact with each other may be fixed to each other by welding or the like, and accordingly, electrical connection between the battery cells <NUM> within the battery cell stack <NUM> may be made.

The battery cells <NUM> are vertically stacked such that the electrode leads are aligned in a direction to constitute the battery cell stack <NUM>. The battery cell stack <NUM> is accommodated in a module frame <NUM> including a lower plate <NUM> and a pair of side walls <NUM> constituting an internal space. For example, the module frame <NUM> may include an upper plate <NUM> and the lower plate <NUM>, which are perpendicular to a stacked surface of the battery cell stack <NUM>, and the pair of side walls <NUM> that are in parallel with the stacked surface of the battery cell stack <NUM> to connect the lower plate <NUM> and the upper plate <NUM>. The battery cell stack <NUM> may be surrounded by the upper plate <NUM>, the lower plate <NUM>, and the pair of sidewalls <NUM>, and the electrode leads of the battery cell stack <NUM> may be accommodated to be exposed by at least one opening (not illustrated) formed in the module frame <NUM>. In this case, the opening may be covered by an end plate (not illustrated) including a configuration for electrically connecting the electrode leads to the outside.

Referring to <FIG>, at least one injection hole <NUM> capable of injecting a resin for forming the resin layer <NUM> to be described later is formed in the lower plate <NUM> of the module frame <NUM>. That is, in a state in which the battery cell stack <NUM> is accommodated in the module frame <NUM>, the battery module <NUM> is disposed such that the lower plate <NUM> is upward, and a resin is injected through the injection hole <NUM> of the lower plate <NUM>. A detailed description thereof will be described later.

The resin layer <NUM> may exist in a state of filling a space between the lower plate <NUM> of the module frame <NUM> and the battery cell stack <NUM>.

The resin layer <NUM>, which is a thermally conductive a resin layer, may include a thermally conductive resin and a detection agent dispersed therein.

The thermally conductive resin includes at least one of an acrylic resin, an epoxy resin, a urethane resin, an olefin resin, an EVA resin, and a silicone resin.

In the present exemplary embodiment, the detection agent includes a contrast agent. The contrast agent, which is a component included to monitor an injection state of a resin composition in a method of manufacturing the battery module <NUM> to be described later, may have a characteristic that it absorbs X-rays such that a flow of the resin may be seen as an image during computer tomography (CT).

Since the injection state of the resin composition is monitored by using the contrast agent, a separate detection hole for checking the injection of the resin composition is not required. That is, as illustrated in <FIG>, at least one injection hole <NUM> is formed in the lower plate <NUM> according to the present exemplary embodiment, and no detection hole is formed. Since the detection hole is not formed, when the resin composition is injected, the resin composition is not wasted because an over-injected resin composition does not leak through the detection hole, or a separate process for removing the leaked resin composition may not need to be performed. In addition, even when no detection hole is formed, monitoring using a contrast agent is possible, so that a resin composition may be uniformly injected into an entire area corresponding to the lower plate <NUM> inside the module frame <NUM>.

A particle type of material may be used as the contrast agent. A compound or a complex containing a metal selected from lead, barium, and gadolinium is used, and may be used as long as it has a characteristic that absorbs X-rays to be detectable. However, the material included in the battery module <NUM> may preferably be an insulator so as to not affect an operation of the battery cell or the like. The particles used as the contrast agent may have a particle diameter of about <NUM> to <NUM>.

When the resin layer <NUM> containing the contrast agent as a detection agent is formed, an injection level of the resin composition may be monitored in real time through computed tomography in a process of injecting the resin composition for forming the resin layer <NUM>. Hereinafter, a manufacturing method of the battery module <NUM> including a process of monitoring injection of a resin composition will be described.

First, the plurality of battery cells <NUM> are stacked and connected by electrode leads to constitute the battery cell stack <NUM>, and the battery cell stack <NUM> is accommodated inside the module frame <NUM>. Next, an end plate is coupled to the opening of the module frame <NUM> to complete a battery module prior to injection of the resin composition.

Subsequently, the lower plate <NUM> of the module frame <NUM> is disposed to face upward, and the resin composition is injected through the injection hole <NUM> formed in the lower plate <NUM>. The resin composition may include at least one of an acrylic resin composition, an epoxy resin composition, a urethane resin composition, an olefin resin composition, a urethane resin composition, an ethylene vinyl acetate (EVA) resin composition, and a silicone resin composition. Further, the resin composition includes a detection agent, and in the present exemplary embodiment, the detection agent includes a contrast agent.

In addition, the resin composition may include other additives capable of improving a characteristic of the resin layer and improving dispersion of the detection agent, for example, diluents, dispersants, surface treatment agents, flame retardants, coupling agents, and the like.

In this case, injection of the resin composition through the injection hole <NUM> is stopped when the resin composition is evenly diffused between the battery cell stack <NUM> and the lower plate <NUM>, by monitoring a flow of the resin composition within the module frame <NUM> in real time while injecting the resin composition containing the contrast agent through the injection hole <NUM>. Herein, the monitoring may be performed through computed tomography, but the present invention is not limited thereto, and is applicable to any non-destructive test capable of detecting a contrast agent. In this case, since the contrast agent is included in the resin composition, a diffusion form of the resin composition during computed tomography may be outputted as an image by photographing a contrast agent that absorbs X-rays, to be monitored. That is, as illustrated in <FIG>, the resin composition injected through a plurality of injection holes <NUM> is diffused in a direction that is away from the injection holes <NUM> as the resin composition is continuously injected, but in the present exemplary embodiment, since the contrast agent is added into the resin composition and it is monitored by computed tomography, the diffusion state as in <FIG> may be checked in real time.

As such, it is possible to check in real time whether the resin composition is evenly distributed over the entire area corresponding to the lower plate <NUM> inside the module frame <NUM> and thus stop the injection of the resin composition by monitoring the flow and distribution of the resin composition inside the module frame <NUM> through the non-destructive test by adding the contrast agent into the resin composition. Accordingly, since it is not necessary to form a detection hole for monitoring, it is possible to achieve excellent cooling performance depending on the even distribution of the resin composition without allowing the resin composition to leak through the detection hole to waste a raw material or performing a separate process for removing the leaking resin composition.

Subsequently, the resin layer <NUM> is formed by curing the injected resin composition, thereby obtaining the battery module <NUM>.

As described above, according to the present exemplary embodiment, it is possible to sufficiently inject the resin composition until the resin composition is uniformly dispersed throughout an entire interior of the lower plate <NUM> while preventing leakage of the resin composition by allowing the resin composition to contain a contrast agent, to be monitored in real time through the non-destructive test such as computed tomography, and to not have a separate detection hole in the process of injecting the resin composition for forming the resin layer <NUM> inside the module frame <NUM>. Accordingly, it is possible to prevent the waste of a raw material resin composition due to a leakage of the resin composition and the occurrence of an additional process for removing it, and also, excellent cooling performance of the battery module <NUM> may be secured by uniformly injecting the resin composition into the module case <NUM>.

In another exemplary embodiment of the present invention, descriptions of the same parts as those of the battery module and the manufacturing method according to the above-described exemplary embodiment will be omitted, and only differences will be described.

<FIG> illustrates a cross-section of a battery module according to another exemplary embodiment of the present invention, <FIG> illustrates a state viewed from a side of a lower plate in a battery module according to another exemplary embodiment of the present invention, <FIG> illustrates a view for describing a flow of a resin according to another exemplary embodiment of the present invention, and <FIG> illustrates a view for describing a flow of a resin according to a comparative example.

As illustrated in <FIG> and <FIG>, according to another exemplary embodiment of the present invention, the lower plate <NUM> includes at least one transparent window <NUM> that is spaced apart from the at least one injection hole <NUM>. The transparent window <NUM> may be spaced from at least one injection hole <NUM> along a longitudinal direction of the lower plate <NUM> (that is, in an y-axis direction of <FIG>), and may be positioned near opposite ends of the lower plate <NUM>. For example, as illustrated in <FIG>, a plurality of injection holes <NUM> may be arranged along a width direction (an x-axis direction of <FIG>) of the lower plate <NUM> near a center of the lower plate <NUM> in a length direction, and at least one transparent window <NUM> may be positioned at positions that are spaced apart from each other along the length direction of the lower plate <NUM> from the injection holes <NUM> (i.e., in the y-axis direction of <FIG>).

The transparent window <NUM> includes at least one detection hole <NUM> formed in the lower plate <NUM> and a transparent tape <NUM> attached to an outer surface of the lower plate <NUM> to correspond to the detection hole <NUM>. The detection hole <NUM> is a hole formed in the lower plate <NUM> at a position of the transparent window <NUM>, and the transparent tape <NUM> is attached in such a way so as to block the detection hole <NUM> from the outside. The transparent tape <NUM> is attached over a plurality of detection holes <NUM> in <FIG>, but it may be formed as small pieces individually attached to correspond to each of the detection holes.

The transparent tape <NUM> may be a tape having an adhesive surface, it may be a combination of a double-sided tape and a transparent plate, and it may not be particularly limited as long as it has a shape that can block the detection hole <NUM> while the resin layer <NUM> can be observed.

In the present exemplary embodiment, the resin layer <NUM> contains a coloring material as a detection agent. The coloring material may be pigment particles, and is not particularly limited as long as it is a configuration that is visible from the outside through the transparent window <NUM>. The pigment particles used as the coloring material may have a particle diameter of about <NUM> to <NUM>.

As such, a configuration of the transparent window <NUM> and the coloring material may be allowed to easily monitor the injection state of the resin composition during manufacture of the battery module <NUM>, may be allowed to prevent the resin composition that is over-injected from leaking out of the detection hole <NUM>, and may allow the resin composition to be uniformly diffused between the lower plate <NUM> and the battery cell assembly <NUM>.

In addition, in the case of forming the resin layer <NUM> of the present exemplary embodiment, a distribution status of the resin composition may be monitored quickly and more accurately by observing a color change of the transparent window <NUM> through a color difference meter in a process of injecting the resin composition for forming the resin layer <NUM>. That is, in injecting the resin composition through the injection hole <NUM> formed in the lower plate <NUM>, since the resin composition contains a coloring material as a detection agent, when the resin composition reaches the transparent window <NUM>, a change thereof may be more easily derived.

In addition, in the present exemplary embodiment, since the detection hole <NUM> is blocked by the transparent tape <NUM>, as described above, the resin composition may be prevented from leaking out of the detection hole <NUM>, and the resin composition may be uniformly diffused between the lower plate <NUM> and the battery cell assembly <NUM>. As illustrated in <FIG>, the resin composition injected through the injection hole <NUM> is diffused toward an end portion of the lower plate <NUM>, when it reaches a position of the detection hole <NUM>, leakage to the outside is prevented by the transparent tape <NUM> formed outside the detection hole <NUM>, and it moves back to an interior of the lower plate <NUM> by pressure of the transparent tape <NUM>. Accordingly, as illustrated in <FIG> and <FIG> illustrating a cross-sectional view taken along a line b-b' of <FIG>), the resin composition may be evenly spread not only at a portion that is adjacent to the detection hole <NUM>, but also at a portion that is further away from the detection hole <NUM> and to an end portion of the lower plate <NUM>. In addition, the resin layer <NUM> formed thereby is formed to fill the interior of the detection hole <NUM> and to contact the transparent tape <NUM> as illustrated in <FIG>.

On the other hand, as illustrated in <FIG>, in the case of having only the detection hole <NUM> in a form of a hole formed in the lower plate <NUM> instead of a form of the transparent window <NUM>, even when the resin composition is observed in the detection hole <NUM> and the injection is stopped, the resin composition is distributed only in a portion close to the detection hole <NUM>, and does not reach a portion spaced from the detection hole <NUM>. As a result, a portion in which the resin layer <NUM> is not formed exists, and sufficient cooling performance for the battery module <NUM> may not be obtained. In addition, as in the present exemplary embodiment as shown in <FIG>, in a configuration of <FIG>, when an injection amount is increased to diffuse the resin composition to the end portion of the lower plate <NUM>, the resin composition overflows through the detection hole <NUM> so that the raw resin composition is wasted, and an additional process is needed to remove the overflowed resin composition.

As described above, according to the present exemplary embodiment, it is possible to sufficiently inject the resin composition until the resin composition is uniformly dispersed throughout an entire interior of the lower plate <NUM> while preventing leakage of the resin composition by including the coloring material in the resin composition and monitoring the diffusion of the resin composition with the transparent window <NUM> made of the detection hole <NUM> and the transparent tape <NUM> for blocking it in the process of injecting the resin composition for forming the resin layer <NUM> inside the module frame <NUM>. Accordingly, it is possible to prevent the waste of a raw material resin composition due to a leakage of the resin composition and the occurrence of an additional process for removing it, and also, excellent cooling performance of the battery module <NUM> may be secured by uniformly injecting the resin composition into the module case <NUM>.

Claim 1:
A battery module comprising:
a module frame configured to include a lower plate and a pair of side walls constituting an internal space;
a battery cell stack disposed in the internal space of the module frame to include a plurality of battery cells that are stacked to be adjacent to each other side by side; and
a resin layer disposed between the lower plate and the battery cell stack
wherein the resin layer includes a detection agent selected from a contrast agent and a coloring material
wherein the contrast agent is a compound or a complex containing a metal selected from lead, barium and gadolinium, wherein the lower plate includes at least one injection hole,
wherein when the detection agent is a coloring material, the lower plate includes at least one transparent window that is spaced from the at least one injection hole, the at least one transparent window having at least one detection hole formed in the lower plate and a transparent tape attached to an outer surface of the lower plate to correspond to the detection hole.