Patent Description:
The present invention relates to a multi-battery pack configured such that a case frame of a battery pack includes a through-hole and a plurality of battery packs is fastened to each other by a long bolt inserted through the through-hole, whereby the multi-battery pack has a compact structure.

With technological development of mobile devices, such as smartphones, laptop computers, and digital cameras, and an increase in demand therefor, research on secondary batteries, which are capable of being charged and discharged, has been actively conducted. In addition, secondary batteries, which are energy sources substituting for fossil fuels causing air pollution, have been applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (P-HEV), and an energy storage system (ESS).

There are a lithium ion battery, a lithium polymer battery, a nickel-cadmium battery, a nickel-hydride battery, and a nickel-zinc battery as secondary batteries that are widely used at present. The operating voltage of a unit secondary battery cell, i.e. a unit battery cell, is about <NUM>. 0V to <NUM>. In the case in which output voltage higher than the above operating voltage is required, therefore, a plurality of battery cells may be connected to each other in series to constitute a cell module assembly. In addition, cell module assemblies may be connected to each other in series or in parallel to constitute a battery module depending on required output voltage or charge and discharge capacities. In general, a battery pack is manufactured using at least one battery module by adding an additional component.

Although the battery pack is used alone, a multi-battery pack including a plurality of battery packs connected to each other in series or in parallel so as to correspond to a device that requires high capacity and high output, such as an electric vehicle, has been proposed.

In a conventional multi-battery pack, however, a separate bracket is necessary to mount the multi-battery pack to a device, whereby space is wasted and cost is increased.

In addition, a separate apparatus and a space therefor are necessary to fix a plurality of battery packs after the battery packs are stacked.

<CIT> relates to a battery module where a plurality of assembled batteries are accommodated in an exterior case formed in an approximately hexahedral or cubic shape, each assembled battery including a plurality of cylindrical unit cells electrically connected such that polarities thereof are alternating. <CIT> and <CIT> relate to a battery modules for electric vehicles. <CIT> relates to square aluminum shell battery double-layer module, which is used for various double-layer aluminum shell battery modules. <CIT> concerns a battery pack which comprises at a battery module with a plurality of battery cells. <CIT> relates to a battery pack having increased safety and an overall compact structure.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a multi-battery pack configured such that a case frame of a battery pack includes a through-hole and a plurality of battery packs is fastened to each other by a long bolt inserted through the through-hole, whereby the multi-battery pack has a compact structure.

In order to accomplish the above object, a multi-battery pack according to the present invention includes a plurality of stacked battery packs and a plurality of long bolts configured to couple the plurality of battery packs to each other and to fix the plurality of battery packs to a device, wherein each of the battery packs includes a plurality of battery cells and a case configured to receive the plurality of battery cells therein, the case includes a case frame defining a space configured to receive the battery cells therein, the case frame being provided at an outside thereof with a plurality of through-holes through which the long bolts are inserted, a lower cover coupled to a lower part of the case frame, and an upper cover coupled to an upper part of the case frame, and the upper cover includes a circular first fastening hole and a second fastening hole having one side open in a C-shape, the first fastening hole and the second fastening hole being configured to allow the long bolts to be fastened therethrough.

Also, in the multi-battery pack according to the present invention, the upper cover may further include a third fastening hole configured to allow the upper cover to be fastened to the case frame therethrough.

Also, in the multi-battery pack according to the present invention, the lower cover may be provided at positions thereof corresponding to the first fastening hole and the second fastening hole of the upper cover with an equal number of fastening holes having identical shapes.

Also, in the multi-battery pack according to the present invention, a hollow cylindrical bushing configured to prevent deformation of the case due to fastening of the long bolts is inserted into each of the through-holes.

Also, in the multi-battery pack according to the present invention, the bushing protrudes and extends upward from the upper cover to be inserted into the lower cover of the battery pack stacked thereon.

Also, in the multi-battery pack according to the present invention, the sum in number of the first fastening hole and the second fastening hole may be equal to the number of the through-holes of the case frame.

Also, in the multi-battery pack according to the present invention, the first fastening hole may be singly formed in the upper cover.

Also, in the multi-battery pack according to the present invention, the case frame may be formed by injection molding.

Also, in the multi-battery pack according to the present invention, the case frame may be injection-molded in the state in which the bushing is inserted therein.

In addition, the present invention provides a device including the multi-battery pack according to the present invention.

A multi-battery pack according to the present invention has an advantage in that through-holes are formed using extra corner spaces of a battery pack case, and battery packs are fastened to each other and at the same time are fastened to a device using long bolts, whereby no separate space and apparatus are necessary.

In addition, the multi-battery pack according to the present invention has an advantage in that an upper cover includes fastening holes having different shapes, whereby battery pack cases may be easily fastened to each other even though minute tolerance occurs between the battery pack cases.

Hereinafter, a multi-battery pack according to the present invention will be described with reference to the accompanying drawings.

<FIG> is a front view schematically showing a multi-battery pack mounted to a device according to an embodiment of the present invention, and <FIG> is a perspective view showing a multi-battery pack according to an embodiment of the present invention.

When describing the multi-battery pack according to the present invention with reference to <FIG> and <FIG>, the multi-battery pack <NUM> is formed by stacking a plurality of battery packs <NUM> and coupling the stacked battery packs <NUM> to each other using a long bolt <NUM>.

The long bolt <NUM>, which is configured to have a length greater than the overall height of the stacked battery packs <NUM>, is inserted through the battery packs <NUM> to couple the battery packs <NUM> to each other and to fix the multi-battery pack <NUM> to a device D, to which the multi-battery pack is mounted.

It is preferable for a plurality of long bolts <NUM> to be provided at the multi-battery pack <NUM> in order to stably couple the battery packs <NUM> to each other and to fix the battery packs to the device D.

In the present invention, as shown in <FIG> and <FIG>, the case in which the long bolts are provided at corners and middle parts of long sides of the multi-battery pack is shown by way of example. However, the number of long bolts <NUM> is not limited thereto, and may be appropriately selected in consideration of the size or weight of the multi-battery pack.

In addition, the material for the long bolt <NUM> is not particularly restricted, and various known materials used in a battery pack manufacturing process may be used.

Meanwhile, <FIG> is a perspective view showing a battery pack according to an embodiment of the present invention, and <FIG> is a plan view showing an upper cover of a battery pack case according to an embodiment of the present invention.

When describing the battery pack <NUM> constituting the multi-battery pack <NUM> according to the present invention with reference to <FIG> and <FIG>, the battery pack <NUM> includes a plurality of battery cells received in a case in a state of being connected to each other in series or in parallel and various kinds of components configured to protect and control the received battery cells.

The battery cell is generally manufactured through a process of receiving an electrode assembly, configured such that electrodes and separators are alternately stacked, in a case, injecting an electrolytic solution into the case, and hermetically sealing the case. The kind of the received battery cell is not particularly restricted. Any one of various known battery cells, such as a pouch-shaped battery cell, a cylindrical battery cell, and a prismatic battery cell, may be appropriately used as needed. Depending on circumstances, the plurality of battery cells may also be manufactured in the form of a battery module or a cell assembly so as to be received.

In addition, the case of the battery pack <NUM> mainly includes a case frame <NUM> defining a space in which the plurality of battery cells is received, a lower cover coupled to a lower part of the case frame <NUM>, and an upper cover <NUM> coupled to an upper part of the case frame <NUM>.

Here, the upper cover <NUM> includes a first fastening hole <NUM> and second fastening holes <NUM>, through which the long bolts <NUM> are inserted, and third fastening holes <NUM>, through which fastening means for coupling with the case frame <NUM> after the battery cells are received are inserted.

In the present invention, although not separately shown, the lower cover is also provided at positions thereof corresponding to the first fastening hole <NUM> and the second fastening holes <NUM> of the upper cover <NUM> with an equal number of fastening holes having identical shapes, through which the long bolts <NUM> are inserted.

In addition, fastening holes, through which fastening means for coupling with the case frame <NUM> are inserted, are also provided in the lower cover. The number or position of the fastening holes may be identical to the number or position of the fastening holes formed in the upper cover <NUM>, or may be designed so as to be different from the number or position of the fastening holes formed in the upper cover depending on circumstances.

Next, through-holes, through which the long bolts <NUM> are inserted, are formed in the case frame <NUM> at positions corresponding to the first fastening hole <NUM> and the second fastening holes <NUM> in equal number.

The through-holes are formed using extra spaces of the case frame <NUM>, such as inner corner spaces, whereby the through-holes are formed without an additional increase in size of the case frame <NUM>, and therefore it is possible to prevent waste of a separate space necessary to form the multi-battery pack <NUM>.

In addition, fastening recesses are formed in the case frame <NUM> at positions corresponding to the third fastening holes <NUM>, whereby the upper cover <NUM> and the lower cover may be coupled to the case frame <NUM> using fastening means, such as bolts. The shape of the fastening recesses may be appropriately selected depending on the fastening means applied thereto.

Meanwhile, as shown in <FIG>, the first fastening hole <NUM> of the upper cover <NUM> is circular, and the long bolt <NUM> is inserted through the first fastening hole in order to fix the battery packs <NUM>.

Even though identical battery pack cases are manufactured through identical processes using identical materials, however, minute tolerance may occur between the battery pack cases or between the upper and lower covers and the case frame <NUM> in each of the battery pack cases.

If all fastening holes of the upper cover, through which the long bolts <NUM> are inserted, are circular, like the first fastening hole <NUM>, fastening may be difficult when the battery packs <NUM> are stacked to form the multi-battery pack <NUM>, or force higher than necessary may be applied for fastening, whereby deformation may occur.

If the size of the first fastening hole <NUM> is increased so as to be greater than necessary in order to prevent this problem, the upper cover <NUM> may be misaligned when the long bolt <NUM> is fastened.

In consideration of the above problems, the battery pack <NUM> according to the present invention is configured such that each second fastening hole <NUM> is formed in a C-shape such that one side of the second fastening hole is open to the outside so as to have an appropriate margin, unlike the first fastening hole <NUM>, and therefore, it is possible to reduce tolerance between stacked battery packs <NUM>.

It is preferable for the number of the first fastening hole <NUM> to be one such that the first fastening hole is formed in any one of the four corners of each upper cover <NUM>, and it is preferable for the number of the second fastening holes <NUM> to be a number obtained by subtracting the number of the first fastening hole <NUM> from the total number of fastening holes necessary to fasten the long bolts <NUM>.

Although the total number of the fastening holes formed in each upper cover <NUM> in order to fasten the long bolts <NUM> is not particularly restricted, the number of the fastening holes is equal to the number of the long bolts <NUM> used for the multi-battery pack <NUM>, and it is preferable for the fastening holes to be formed in at least the four corners of the upper cover one by one in order to securely fix the multi-battery pack <NUM>.

Of course, the fastening holes may be further formed in sides of the upper cover between the four corners in consideration of the size of the battery pack <NUM>.

Meanwhile, pressure may be applied to the case frame <NUM> during fastening of the long bolts <NUM> inserted through the through-holes, whereby the case frame <NUM> may be deformed.

In order to prevent deformation of the case frame <NUM> due to fastening of the long bolts <NUM>, a bushing may be inserted into each through-hole of the case frame <NUM>.

<FIG> is a sectional view showing the multi-battery pack through which a long bolt according to an embodiment of the present invention is inserted, and <FIG> is a perspective view showing a portion of the battery pack into which a bushing according to an embodiment of the present invention is inserted.

When describing the bushing according to the present invention with reference to <FIG>, a hollow cylindrical bushing <NUM> is inserted into each of the through-holes of each battery pack <NUM>, through which the long bolts <NUM> are inserted.

That is, a bushing <NUM> having an outer diameter corresponding to the inner diameter of the through-hole and an inner diameter corresponding to the outer diameter of the long bolt <NUM>, which is inserted through the bushing, is inserted into the through-hole, and the long bolt <NUM> is inserted into the inserted bushing <NUM>.

It is preferable for the bushing <NUM> to have higher compressive stress than the case frame <NUM> in order to prevent deformation of the case frame <NUM> due to fastening of the long bolt <NUM>.

In addition, although the bushing <NUM> is capable of preventing deformation of the case frame <NUM> due to fastening of the long bolt <NUM> even in the case in which the length of the bushing is equal to the length of the through-hole of the case frame, the length of the bushing is greater than the length of the through-hole such that a portion of the bushing protrudes upwards from the upper cover <NUM>, as shown in <FIG>.

The portion of the bushing <NUM> protruding as described above is inserted into a fastening hole of a lower cover of a battery pack <NUM> stacked thereon, whereby a predetermined level of fixing force is provided even before fastening of the long bolt <NUM>, and the bushing aligns the positions of the battery packs <NUM> such that subsequent fastening of the long bolt <NUM> is easily performed.

That is, when described based on one battery pack <NUM>, one end of the inserted bushing <NUM> is located at a lower part of the through-hole, a portion of the other end of the bushing protrudes and extends upward from the upper cover <NUM>, the bushing <NUM> is not inserted into the fastening hole of the lower cover, and the protruding bushing <NUM> of the battery pack <NUM> located on the lower side when the battery packs <NUM> are stacked is inserted into the fastening hole of the lower cover.

The bushing <NUM> may be manufactured independent of the case frame <NUM> depending on the material for the case frame <NUM> and a method of forming the case frame, and may be inserted into the through-hole of the case frame <NUM> after the case frame is formed, or may be inserted into the case frame <NUM> during manufacture of the case frame in order to form the case frame <NUM> having the bushing <NUM> inserted therein.

For example, in the case in which the case frame <NUM> is formed through an injection molding method using plastic, a pre-manufactured bushing <NUM> may be inserted in advance during injection molding in order to form the case frame <NUM>.

Meanwhile, a bushing <NUM> is inserted into each through-hole of the case frame <NUM> in order to prevent deformation of the case. However, an appropriate number of bushings may be selected based on the number of through-holes. Even at this time, however, it is preferable for the bushings to be inserted into at least four corners of the case frame <NUM>.

Although the multi-battery pack <NUM> according to the present invention may be mounted to the device D, as shown in <FIG>, the multi-battery pack may be mounted in various forms and directions depending on the environment of the device D to which the multi-battery pack is mounted.

<FIG> is a perspective view showing a multi-battery pack according to another embodiment of the present invention.

The multi-battery pack <NUM> of <FIG> is a vertical form of the multi-battery pack <NUM> of <FIG>. In the case in which the multi-battery pack <NUM> is mounted to the device D, as shown, it is impossible to directly fix the multi-battery pack to the device D using the long bolts <NUM>.

Consequently, an additional fixing bracket <NUM> is necessary to fix the multi-battery pack <NUM> to the device D.

One side of the fixing bracket <NUM> of <FIG> is fixed to the multi-battery pack <NUM> through a first fixing means <NUM>, and the other side of the fixing bracket is fixed to the device D through a second fixing means.

Various known mechanical fastening means, such as a screw, may be used as the first fixing means <NUM> and the second fixing means <NUM>.

Meanwhile, as shown in <FIG>, a fixing means insertion port <NUM>, through which the first fixing means <NUM> is inserted, is formed in the case frame <NUM>.

Claim 1:
A multi-battery pack (<NUM>, <NUM>) comprising:
a plurality of stacked battery packs (<NUM>); and
a plurality of long bolts (<NUM>) configured to couple the plurality of battery packs (<NUM>) to each other and to fix the plurality of battery packs (<NUM>) to a device (D),
wherein each of the battery packs (<NUM>) comprises a plurality of battery cells and a case configured to receive the plurality of battery cells therein,
wherein the case comprises:
a case frame (<NUM>) defining a space configured to receive the battery cells therein, the case frame (<NUM>) being provided at an outside thereof with a plurality of through-holes through which the long bolts (<NUM>) are inserted;
a lower cover coupled to a lower part of the case frame (<NUM>); and
an upper cover (<NUM>) coupled to an upper part of the case frame (<NUM>), and
wherein the upper cover (<NUM>) comprises a circular first fastening hole (<NUM>) and a second fastening hole (<NUM>) having one side open in a C-shape, the first fastening hole (<NUM>) and the second fastening hole (<NUM>) being configured to allow the long bolts (<NUM>) to be fastened therethrough, wherein a hollow cylindrical bushing (<NUM>) configured to prevent deformation of the case due to fastening of the long bolts (<NUM>) is inserted into each of the through-holes, and wherein the bushing (<NUM>) protrudes and extends upward from the upper cover (<NUM>) to be inserted into the lower cover of the battery pack (<NUM>) stacked thereon.