Patent Description:
Secondary batteries having high application characteristics and electrical characteristics such as high energy density according to their products are widely applied to battery vehicles, hybrid vehicles, and electric power storage devices driven by electric driving sources as well as portable devices. These secondary batteries are attracting attention as new energy sources for improving environmental-friendliness and energy efficiency in that they do not generate any by-products of energy use as well as their primary merit, in which they can drastically reduce the use of fossil fuels.

In small mobile devices, one, or two, or three battery cells are used per device, while medium and large devices such as automobiles require high power/large capacity. Therefore, a medium battery module and a large battery module in which a plurality of battery cells are electrically connected is used.

Since it is preferable for medium and large battery modules to be manufactured with as small a size and weight as possible, a prismatic battery and a pouch-type battery, which may have a high integration degree and have a small weight with respect to capacity, are mainly used as a battery cell of the medium and large battery modules. Meanwhile, in order to protect the cell stack from external impact, heat, or vibration, the battery module may include a frame member that receives the battery cell stack in an internal space with front and rear openings.

<FIG> is a perspective view showing a battery module according to a conventional module frame. <FIG> is a view showing a cross-section taken along an xz plane <FIG>.

Referring to <FIG> and <FIG>, a battery module may include a module frame <NUM> of which a front surface and a rear surface are opened to cover a battery cell stack <NUM> formed by stacking a plurality of battery cells <NUM> and an end plate <NUM> covering the front surface and the rear surface of the module frame <NUM>. The module frame <NUM> may include a U-shaped frame 10a and an upper plate 10b covering the opened portion of the U-shaped frame 10a. The U-shaped frame 10a may include a bottom part 10a1 covering the lower surface of the battery cell stack <NUM> and two side parts 10a2 having a structure protruded upward from both sides of the bottom part 10a1. The end plate <NUM> may include a front plate 20a covering one side of the module frame <NUM> and a rear plate 20b covering the other side of the module frame <NUM>.

To form such a battery module, in the state that the battery cell stack <NUM> is mounted inside the module frame <NUM>, welding may be performed to join the U-shaped frame 10a and the upper plate 10b of the module frame <NUM>. At this time, an assembly failure may occur during the assembling process in which the upper plate 10b is placed on the U-shaped frame 10a. Particularly, when a welding part WP is formed between the upper plate 10b and the side part of the U-shaped frame 10a, a guide for assembly alignment is not provided, which may cause defects.

Document <CIT> discloses a battery module of known type.

Document <CIT> discloses a battery module having a U-shaped frame member and a top cover plate assembled.

Document <CIT> discloses a battery module comprising one pair of side plates pressed in or fitted to both ends of a top and a bottom plate.

Document <CIT> discloses an electrical storage device provided with an exterior member body and a lid member fixed to the exterior member body by means of fixing portions.

Therefore, there is a need for a technology that can solve this problem of conventional art.

The problem to be solved by the present invention is to provide a battery module with improved assembly ability and a battery pack including the same.

A battery module according to an embodiment of the present invention is defined in the attached claims.

A battery pack according to another embodiment of the present invention is also provided.

According to embodiments, by forming a protrude-type assemble guide structure in the module frame, it is possible to prevent a misalignment from occurring when assembling the module frame. Through this assembly improvement, it is possible to prevent welding defects from occurring during a module frame welding.

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

Descriptions of parts not related to the present invention are omitted, and like reference numerals designate like 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 thickness 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. In addition, the word "~ on" means positioning on or below the object portion, but does not essentially mean positioning on the upper side of the object portion based on a gravity opposite direction.

In addition, unless explicitly described to the contrary, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

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-section" means when a cross-section taken by vertically cutting an object portion is viewed from the side.

<FIG> is an exploded perspective view showing a battery module according to an embodiment of the present invention.

Referring to <FIG>, a battery module according to an embodiment of the present invention includes a battery cell stack <NUM> in which a plurality of battery cells <NUM> are stacked, a module frame <NUM> receiving the battery cell stack <NUM>, a busbar frame <NUM> formed on the front/rear surfaces of the battery cell stack <NUM>, and an end plate <NUM> covering the outside of the busbar frame <NUM> based on the d battery cell stack <NUM>.

The battery cell <NUM> according to the present embodiment is a secondary battery and may be configured as a pouch-type secondary battery. The battery cells <NUM> is configured in plurality, and a plurality of battery cells <NUM> is stacked to each other to be electrically connected to each other to form a battery cell stack <NUM>. A plurality of battery cells <NUM> may include an electrode assembly, a cell case, and an electrode lead protruded from the electrode assembly, respectively.

The busbar frame <NUM> may be equipped with a busbar <NUM> and a connector <NUM>. The connector <NUM> may sense a voltage and temperature from the busbars mounted on the busbar frame <NUM> or a thermistor and transmit it to a BMS (Battery Management System). Among the busbar frames <NUM> formed on the front/rear surfaces of the battery cell stack <NUM>, a first connector <NUM> may be formed on the busbar frame <NUM> positioned in front of the battery cell stack <NUM>, and a second connector <NUM> may be formed on the busbar frame <NUM> positioned at the rear surface of the battery cell stack <NUM>.

Conventionally, a connector was formed on only one busbar frame part of two busbar frames formed on the front/rear surfaces of the battery cell stack <NUM>, and the busbar frame part on which a connector is not formed transmitted the voltage and temperature sensing information to the connector located on the opposite side of the reference of the battery cell stack through a flexible flat cable. At this time, the process of assembling the flexible flat cable and the process of checking whether there is any problem in the connection through the flexible flat cable were separately required by positioning the flexible flat cable on the upper side of the battery cell stack.

According to an embodiment of the present invention, the first and second connectors <NUM> and <NUM> are separately formed on one side of each busbar frame <NUM> formed on the front/rear surfaces of the battery cell stack <NUM>, so that the sensed voltage and temperature may be transmitted to the BMS in both directions through the connectors formed on each busbar frame <NUM> without any need of the separate assemble of the flexible flat cable. Through this, a manufacturing cost of the battery module may be reduced and the battery module structure may be simplified. In addition, the assemble process of the flexible flat cable and the process of checking the connection defects are eliminated, thereby simplifying the battery module manufacturing process.

The battery cell stack <NUM> is disposed in the module frame <NUM>. According to the present embodiment, the module frame <NUM> includes a lower frame <NUM> covering the lower surface and both sides of the battery cell stack <NUM>, and an upper plate <NUM> covering the upper surface of the battery cell stack <NUM>.

In the state that the busbar frame <NUM> is mounted on the front/rear surfaces of the battery cell stack <NUM>, the battery cell stack <NUM> is disposed to the lower frame <NUM>. Thereafter, the upper plate <NUM> is be assembled to cover the upper part of the battery cell stack <NUM>. At this time, by fixing the upper plate <NUM> and the lower frame <NUM>, the battery cell stack <NUM> may be stably disposed within the module frame <NUM>.

The lower frame <NUM> of the module frame <NUM> that accommodates the battery cell stack <NUM> may be a U-shaped frame. The U-shaped frame <NUM> includes a bottom part 210a and two side parts 210b extending upward in the z-direction from both ends of the bottom part 210a. The bottom part 210a covers the lower surface (a direction opposite the z-axis) of the battery cell stack <NUM>, and the side parts 210b cover both sides (a direction of the x-axis and a direction opposite to the x-axis direction) of the battery cell stack <NUM>.

The upper plate <NUM> may be formed as a single plate-shaped structure surrounding the upper surface (the z-axis direction) except for the lower surface and the both sides covered by the U-shaped frame <NUM>. The upper plate <NUM> and the U-shaped frame <NUM> forms a structure that covers the battery cell stack <NUM> up, down, left, and right by being joined by welding or the like while the corresponding corners are in contact with each other. The battery cell stack <NUM> is physically protected through the upper plate <NUM> and the U-shaped frame <NUM>. To this end, the upper plate <NUM> and the U-shaped frame <NUM> may include a metal material having predetermined strength.

As previously described with reference to <FIG> and <FIG> in the state that the battery cell stack <NUM> is mounted inside the module frame <NUM>, welding may be performed to join the U-shaped frame <NUM> and the upper plate <NUM> of the module frame <NUM>. At this time, in order to form the welding part, it is necessary to fix the U-shaped frame <NUM> and the upper plate <NUM> so that the joint surfaces of the side part 210b of the U-shaped frame <NUM> and the upper plate <NUM> are positioned corresponding to each other. However, there is a limit to fixing the U-shaped frame <NUM> and the upper plate <NUM> to closely correspond to each other, and this has a problem in that the welding is not performed smoothly.

In addition, laser welding may be performed for the welding, and damage to internal parts including the battery cells may be caused by the laser itself or welding spatters penetrated during the welding process. At this time, if the assembly defect occurs during the assemble process, in which the upper plate <NUM> is placed on the U-shaped frame <NUM>, the weld line is also misaligned, and in this case, a larger amount of welding spatter is inflowed into the battery module where the battery cells are located, thereby causing problems.

In order to reduce this problem, the battery module according to the present embodiment includes a lower frame having an assemble guide structure of a protruding type, thereby improving the assembly ability of the lower frame and upper plate, thereby preventing the welding defects. This will be described in detail with reference to <FIG> and <FIG>.

<FIG> is a perspective view showing a lower frame included in a battery module of <FIG>. <FIG> is a partial perspective view showing an assembly part of an upper plate and a lower frame in a battery module according to an embodiment of the present invention.

Referring to <FIG>, the upper corner of the side part 210b of the U-shaped frame <NUM> according to the present embodiment forms an assemble guide part <NUM>. The assemble guide part <NUM> is formed as at least one on the upper corner of the side part 210b of the U-shaped frame <NUM>. A plurality of assemble guide parts <NUM> may be formed to be spaced apart from each other while having a predetermined interval therebetween.

The assemble guide part <NUM> according to the present embodiment includes a supporting part 210P of a protrusion shape protruded in the z-axis direction and a depressed part 210D formed on both sides of the supporting part 210P. The depressed part 210D may have an escape shape in which the upper corner of the side part 210b of the U-shaped frame <NUM> is concave in the opposite direction of the z-axis.

Referring to <FIG>, a groove part 220D corresponding to the assemble guide part <NUM> formed on the U-shaped frame <NUM> is formed on the upper plate <NUM> according to the present embodiment. The groove part 220D may have a structure in which both corners of the upper plate <NUM> are depressed in a direction facing each other so that the assemble guide part <NUM> of the U-shaped frame <NUM> may be assembled with the upper plate <NUM>. In this case, an escape part 220P may be formed on both ends of the groove part 220D. The escape part 220P minimizes a gap of the groove part 220D so that the supporting part 210P of the assemble guide part <NUM> may be accurately coupled to the groove part 220D.

According to the present embodiment, by fixing the positions in the x-axis direction and the y-axis direction, not only the assembly ability may be improved, but also the durability of the battery module may be improved.

As shown in <FIG>, like the battery cell stack <NUM> according to an embodiment of the present invention, in the case of a large area module in which the number of the stacked battery cells <NUM> is larger than the number of battery cells <NUM> in the battery cell stack <NUM> shown in FIG. <NUM>, the horizontal direction length of the battery module becomes longer. In the large area module, since the horizontal direction length of the battery module is increased, the load at the center is large and the possibility of a bending deformation increases. Here, the horizontal direction length may mean a length in the direction in which the battery cells are stacked. Due to the bending deformation, the coupling structure of the U-shaped frame <NUM> and the upper plate <NUM> may be distorted depending on the battery module usage condition, but according to the present embodiment, through the strong position fixation in both the x-axis direction and the y-axis direction, the coupling retention between the U-shaped frame <NUM> and the upper plate <NUM> may be improved.

Again, referring to <FIG>, the battery module according to the present embodiment further includes an end plate <NUM> covering the front/rear surfaces of the battery cell stack <NUM>. Through the module frame <NUM> described above, it is possible to physically protect the battery cell stack <NUM> disposed inside. The end plate <NUM> is positioned on the front (the opposite direction of the y-axis) and rear (the y-axis direction) of the battery cell stack <NUM>. This end plate <NUM> is formed to cover the battery cell stack <NUM>, and it is possible to physically protect the battery cell stack <NUM> and other electronic devices from external impact.

Meanwhile, although not specifically shown, a busbar frame <NUM> to which the busbar <NUM> is mounted and an insulating cover for an electrical insulation, etc. are positioned between the battery cell stack <NUM> and the end plate <NUM>.

On the other hand, one or more battery modules according to an embodiment of the present invention may be packaged in a pack case to form a battery pack. The battery pack may be formed by mounting at least one battery module together with various control and protection systems such as a battery management system (BMS) and a cooling system.

Claim 1:
A battery module comprising:
a battery cell stack (<NUM>) in which a plurality of battery cells (<NUM>) are stacked;
a module frame (<NUM>) surrounding the battery cell stack (<NUM>);
a busbar frame (<NUM>) covering the front/rear surfaces of the battery cell stack (<NUM>) exposed from the module frame (<NUM>); and
an end plate (<NUM>) covering the busbar frame (<NUM>),
wherein the module frame (<NUM>) includes a lower frame (<NUM>) including a bottom part (210a) and two side parts (210b) extending upward in the z-direction from both ends of the bottom part (210a) and covering a lower part and both sides of the battery cell stack (<NUM>), and an upper plate (<NUM>) covering an upper part of the battery cell stack (<NUM>), and
at least one assemble guide part (<NUM>) formed as at least one on the upper corner of the side part (210b) of the lower frame (<NUM>),
wherein the assemble guide part (<NUM>) includes a supporting part (210P) of a protrusion shape protruded in the z-axis direction and a depressed part (210D) formed on both sides of the supporting part (210P); and
wherein the upper plate (<NUM>) comprises a groove part (220D) to which the supporting part (210P) of the assemble guide part (<NUM>) is assembled.