Patent Description:
The present disclosure relates to a battery module including a foldable side plate, and a battery pack and a vehicle including the battery module. More specifically, the present disclosure relates to a battery module having a structure in which an electrode lead and a bus bar are welded to each other in a state where a pair of unit modules are pressed simultaneously by using two pairs of foldable side plates connecting the pair of unit modules and then the foldable side plates are unfolded so that the pairs of unit modules are disposed side by side in a longitudinal direction, and a battery pack and a vehicle including the battery module.

Conventionally, when manufacturing a long module by arranging a pair of unit modules, in each of which a cell stack and a bus bar frame are coupled, side by side in a longitudinal direction, surface pressurization is performed to each cell stack individually in order to perform a welding process between an electrode lead and a bus bar for each unit module.

That is, a welding process is performed for coupling the electrode lead and the bus bar in a state where surface pressurization applied to the cell stack pressure is maintained for one unit module, and then the same process is performed for another unit module to make a pair of unit modules. After that, in a state where two unit modules are arranged side by side in the longitudinal direction, a housing is assembled or welded thereto.

However, if this conventional process is used, surface pressurization is inevitably applied to and released from each unit module repeatedly, which causes relative movement between the electrode lead and the bus bar. As a result, stress is accumulated in the electrode lead and the welded portion between the electrode lead and the bus bar.

In addition, the accumulated stress may lead to a product failure due to breakage of a part or damage to the welded portion while a product is being produced or used.

Thus, when manufacturing a battery module of a long module type having a structure in which a pair of unit modules are arranged side by side in the longitudinal direction, it is necessary to continuously maintain the surface pressurization state for the unit modules without repeatedly applying surface pressurization to the unit modules and releasing the surface pressurization. Also, it is demanded to develop a battery module having a structure capable of maintaining the surface pressurization state.

Further prior art is desribed in <CIT> and <CIT>.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to continuously maintaining a surface pressurization state for unit modules without repeatedly applying surface pressurization to the unit modules and releasing the surface pressurization, when manufacturing a battery module of a long module type having a structure in which a pair of unit modules are arranged side by side in the longitudinal direction.

According to one aspect of the present disclosure, the above object is accomplished with the features of claim <NUM> and with a method for manufacturing a battery module with the features of claim <NUM>.

Dependent claims are directed on features of preferred embodiments of the present invention.

According to an embodiment of the present disclosure, a surface pressurization state for unit modules may be continuously maintained without repeatedly applying surface pressurization to the unit modules and releasing the surface pressurization, when manufacturing a battery module of a long module type having a structure in which a pair of unit modules are arranged side by side in the longitudinal direction. Also, it is possible to prevent stress from being accumulated in the electrode lead and the welded portion between the electrode lead and the bus bar.

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 pair of foldable side plates <NUM>, a pair of bus bar frame assemblies <NUM>, an upper housing <NUM>, a lower housing <NUM> and end plates <NUM>.

Referring to <FIG>, the cell stack <NUM> includes a plurality of battery cells <NUM> stacked in a vertical direction (a direction parallel to an X axis of <FIG>) and a plurality of buffering pads <NUM> disposed between neighboring battery cells <NUM> or on an outer side surface of a battery cell <NUM> disposed at an outermost side.

The battery cells <NUM> may be, for example, pouch-type battery cells. If the pouch-type battery cell is used as the battery cell <NUM>, electrode leads <NUM> are provided at one side and the other side of the battery cell <NUM> in the longitudinal direction in parallel to a Y axis in <FIG>, respectively. The electrode lead <NUM> is a thin metal plate connected to an electrode tab formed at an electrode assembly (not shown) that is disposed inside the battery cell <NUM>, namely inside a pouch case, and is drawn out of the pouch case.

The buffering pads <NUM> are interposed at the outer side of the cell stack <NUM> and/or between neighboring battery cells <NUM> to allow the cell stack <NUM> to contract when both surfaces of the cell stack <NUM> are pressed. In order to enable contraction of the cell stack <NUM> as described above, the buffering pad <NUM> is preferably made of an elastic material such as a sponge.

The cell stack <NUM> is coupled to the bus bar frame assembly <NUM> in a state where both sides thereof are pressurized by the foldable side plates <NUM>, and is also coupled by welding the foldable side plates <NUM> and the housings <NUM>, <NUM> in a state of maintaining the pressurization force. That is, inside the completed battery module, the buffering pad <NUM> is in a contracted state, thereby suppressing the generation of swelling caused by repeated use of the battery module, by means of the elastic energy stored therein.

As shown in <FIG>, the cell stack <NUM> includes a first cell stack 100A and a second cell stack 100B arranged side by side in a width direction of the cell stack <NUM> (a direction parallel to the Z axis of <FIG>). The first cell stack 100A and the second cell stack 100B are arranged side by side in the width direction as described above when the foldable side plates <NUM> are in a folded state, as explained later. If the foldable side plates <NUM> are in an unfolded state, the first cell stack 100A and the second cell stack 100B are arranged side by side along the longitudinal direction (a direction parallel to the Y axis of <FIG>).

Referring to <FIG>, the foldable side plate <NUM> is provided in a pair, and the foldable side plates <NUM> are respectively attached to one side surface and the other side surface of the first cell stack 100A and the second cell stack 100B arranged side by side in the width direction (a direction parallel to the Z axis of <FIG>). The foldable side plates <NUM> press the cell stack <NUM> to contract.

Namely, the foldable side plates <NUM> are disposed to cover one side and the other side of the cell stack <NUM> by coupling with the upper housing <NUM> and the lower housing <NUM>, explained later, and also serve to press the cell stack <NUM>.

Referring to <FIG>, the foldable side plates <NUM> include a first side plate <NUM> and a second side plate <NUM> which are hinged to allow relative rotation with each other. By the hinge coupling, as shown in <FIG>, the pair of side plates <NUM> and the pair of side plates <NUM> may be folded so as to be arranged side by side in the width direction (a direction parallel to the Z axis of <FIG>), and, as shown in <FIG>, the pair of side plates <NUM>, <NUM> may be unfolded so as to be arranged side by side in the longitudinal direction (a direction parallel to the Y axis of <FIG>).

Referring to <FIG>, the hinge coupling between the first side plate <NUM> and the second side plate <NUM> may be performed by, for example, fastening between a coupling hole H formed in a corner region at one longitudinal end of the first side plate <NUM> and a coupling protrusion P formed in a corner region of one longitudinal end of the second side plate <NUM>. In addition, it is also possible that the coupling hole H is formed at the second side plate <NUM> and the coupling protrusion P is formed at the first side plate <NUM>.

Referring to <FIG> and <FIG> along with <FIG>, the first pair of side plates <NUM> covers one side surface and the other side surface of the first cell stack 100A (a surface parallel to the Y-Z plane of <FIG>). Similarly, the second pair of side plates <NUM> covers one side surface and the other side surface of the second cell stack 100B (a surface parallel to the Y-Z plane of <FIG>).

Referring to <FIG> and <FIG>, the bus bar frame assembly <NUM> is provided in a pair, each bus bar frame assembly <NUM> includes a front bus bar frame <NUM>, a rear bus bar frame <NUM> and a cover plate <NUM>. The front bus bar frame <NUM>, the rear bus bar frame <NUM> and the cover plate <NUM> are made of a material with electrical insulation such as resin.

In a state where the cell stack <NUM> is pressed by the foldable side plates <NUM> in an arrow direction, the pair of bus bar frame assemblies <NUM> are coupled to cover the front surface and the rear surface (surfaces parallel to the X-Z plane of <FIG> and <FIG>) and the upper surface (a surface plane parallel to the X-Y plane of <FIG> and <FIG>) of the first cell stack 100A and the second cell stack 100B.

The pair of front bus bar frames <NUM> are coupled to cover the front surfaces of the first cell stack 100A and the second cell stack 100B, respectively, and the pair of rear bus bar frames <NUM> are coupled to cover the rear surfaces of the first cell stack 100A and the second cell stack 100B, respectively. In addition, the pair of cover plates <NUM> are coupled to cover the upper surfaces of the first cell stack 100A and the second cell stack 100B, respectively. Both longitudinal ends of the cover plate <NUM> may be hinged to the front bus bar frame <NUM> and the rear bus bar frame <NUM>, respectively, so that the front bus bar frame <NUM> and the rear bus bar frame <NUM> may rotate relative to the cover plate <NUM>.

Due to the hinge coupling structure between the bus bar frames <NUM>, <NUM> and the cover plate <NUM>, after the cover plate <NUM> is placed at a predetermined position on the upper surface of the cell stacks 100A, 100B, the bus bar frames <NUM>, <NUM> may be rotated to accurately cover rotate the front surfaces and the rear surfaces of the cell stacks 100A, 100B.

A plurality of bus bars B are provided on the bus bar frames <NUM>, <NUM> in its longitudinal direction (a direction parallel to the X axis of <FIG> and <FIG>), and the bus bars B are coupled to electrode leads <NUM> drawn out through slits formed at the bus bar frames <NUM>, <NUM> by welding. The electrode leads <NUM> of two or more battery cells <NUM> to be electrically connected to each other may be coupled to one bus bar B.

In addition, a pair of module terminals T are provided on the front bus bar frame <NUM>, and the pair of module terminals T are coupled to the electrode leads <NUM> of the battery cell <NUM> located at an outermost side along a width direction (a direction parallel to the X axis of <FIG> and <FIG>) of the cell stacks 100A, 100B. In the present disclosure, the front bus bar frame <NUM> and the rear bus bar frame <NUM> are distinguished depending on whether the module terminal T is provided or not. That is, in the present disclosure, a bus bar frame at which the module terminal T is formed is defined as the front bus bar frame <NUM>, and a bus bar frame at which the module terminal T is not formed is defined as the rear bus bar frame <NUM>.

Meanwhile, the welding between the electrode lead <NUM> and the bus bar B and the welding between the electrode lead <NUM> and the module terminal T are performed in a state where the pressurization by the foldable side plates <NUM> is maintained, and also are performed in a state where the pair of cell stacks 100A, 100B are arranged adjacently side by side in the width direction since the foldable side plates <NUM> are folded.

As the pair of bus bar frame assemblies <NUM> are coupled, a first module M1 including the first cell stack 100A, the first side plate <NUM> and the bus bar frame assembly <NUM> and a second module M2 including the second cell stack 100B, the second side plate <NUM> and the bus bar frame assembly <NUM> are provided.

Referring to <FIG> and <FIG>, the first side plate <NUM> and the second side plate <NUM> of the foldable side plates <NUM> extend in a direction toward the front bus bar frame <NUM> from the rear bus bar frame <NUM> and have a length extending further to the front bus bar frame <NUM>. In addition, the first side plate <NUM> and the second side plate <NUM> are hinged to each other at a position corresponding to the front bus bar frame <NUM>, among both longitudinal ends thereof.

By doing so, when the foldable side plates <NUM> are unfolded, the first module M1 and the second module M2 are adjacently arranged side by side in the longitudinal direction (a direction parallel to the Y axis of <FIG>) in a state where the front bus bar frames <NUM> thereof face each other. Accordingly, the pair of module terminals T provided to the first module M1 and the pair of module terminals T provided to the second module M2 face each other.

Meanwhile, even when the foldable side plates <NUM> are unfolded so that the pair of modules M1, M2 are adjacently arranged side by side in the longitudinal direction, the pressurization to the cell stack <NUM> by the foldable side plates <NUM> is maintained.

Referring to <FIG>, the upper housing <NUM> and the lower housing <NUM> cover the upper surfaces and the lower surfaces (surfaces parallel to the X-Y plane of <FIG>) of the first module M1 and the second module M2, respectively, in a state where the pair of foldable side plates <NUM> are unfolded while maintaining the pressurization to the first module M1 and the second module M2.

Both edges of the upper housing <NUM> and the lower housing <NUM> in the width direction (a direction parallel to the X axis of <FIG>) are coupled to both edges of the foldable side plate <NUM> in the width direction (a surface parallel to the Y-Z plane of <FIG>) by welding. The coupling between the housings <NUM>, <NUM> and the foldable side plates <NUM> by welding is performed in a state where the cell stack <NUM> keeps pressed by the foldable side plates <NUM>.

As shown in <FIG>, the end plate <NUM> is provided in a pair, and the pair of end plates <NUM> cover with the front surface and the rear surface of the battery module according to an embodiment of the present disclosure (surfaces parallel to the X-Z plane of <FIG>), respectively. That is, the pair of end plates <NUM> are coupled to the rear surfaces of the first module M1 and the second module M2, respectively.

As described above, the battery module according to an embodiment of the present disclosure has a structure capable of performing a following process while continuously maintaining a state where the pair of modules M1, M2 are pressed using the foldable side plates <NUM>.

Specifically, in the battery module, by applying the foldable side plates <NUM>, as shown in <FIG>, the pair of modules M1, M2 may be easily pressurized in a state of being adjacently arranged side by side in the width direction, and the electrode lead <NUM> and the bus bar B may be welded smoothly. In case of a battery module to which the foldable side plate <NUM> is not applied, similar to that shown in <FIG>, after the pair of modules are arranged adjacent to each other along the longitudinal direction, the electrode lead and the bus bar must be welded in a state where both sides of the pair of modules are pressed using the side plates. However, in this case, due to a very narrow space between the modules, welding may not be performed smoothly at the front surface of the module. In addition, if the pair of modules are arranged side by side in the longitudinal direction and the side plates are attached thereto after the welding process is individually performed to each of the pair of modules, it is not possible to continuously pressurize the modules.

In the battery module structure according to an embodiment of the present disclosure, however, welding is performed in a state where the foldable side plates <NUM> are folded, while maintaining the pressurization to the modules M1, M2 by the foldable side plates <NUM>. Also, since the housings <NUM>, <NUM> are folded in a state where the foldable side plates <NUM> are unfolded, it is possible to ensure easy welding and maintain continuous pressurization during in the process.

A method for manufacturing the battery module according to an embodiment of the present disclosure includes (S1) a cell stack arranging step; (S2) a pressurization initiating step; (S3) a module forming step; (S4) an unfolding step; (S5) a housing coupling step; and (S6) an end plate coupling step.

Firstly, in the cell stack arranging step (S1), a pair of battery cell stacks 100A, 100B are provided to be arranged side by side in the width direction of the battery cell stacks 100A, 100B. In the pressurization initiating step (S2), both sides of the pair of battery cell stacks 100A, 100B in the width direction are pressurized using a pair of hinge-coupled foldable side plates <NUM> in a folded state.

Then, in the module forming step (S3), in a state where the pressurization to the cell stacks 100A, 100B initiated in the pressurization initiating step (S2) is maintained, bus bar frame assemblies <NUM> are coupled to cover front surfaces and rear surfaces of the cell stacks 100A, 100B, respectively, to form a first module M1 and a second module M2, each including the cell stack <NUM> and the bus bar frame assembly <NUM>. Then, in the unfolding step (S4), in a state where the pressurization to the cell stack <NUM> performed in the module forming step (S3) is maintained, the foldable side plates <NUM> are unfolded so that the first module M1 and the second module M2 are arranged side by side in the longitudinal direction.

In the housing coupling step (S5), in a state where the pressurization to the cell stack <NUM> performed in the unfolding step (S4) maintained, an upper housing <NUM> and a lower housing <NUM> covering the upper surfaces and the lower surfaces of the first module M1 and the second module M2 are coupled to the foldable side plates <NUM> by welding. In the end plate coupling step (S6), a pair of end plates <NUM> covering rear surfaces of the first module M1 and the second module M2 are coupled. The steps S1 to S6 are performed in order.

Claim 1:
A battery module comprising:
a first module (M1) and a second module (M2), each including a cell stack (<NUM>) having a plurality of battery cells (<NUM>) stacked vertically in a direction parallel to an X-axis of a rectangular coordinate system, and a bus bar frame assembly (<NUM>) configured to cover a front surface and a rear surface, each extending in parallel to an X-Z plane of the above coordinate system of the cell stack (<NUM>); and
two pairs of foldable side plates (<NUM>) including a first pair of side plates (<NUM>) configured to cover and pressurize one side surface and the other side surface of the first module (M1) and a second pair of side plates (<NUM>) configured to cover and pressurize one side surface and the other side surface of the second module (M2) and hinged to the first pair of side plates (<NUM>), each pair of side plates (<NUM>, <NUM>) being provided such that their surfaces are parallel to a Y-Z plane in the above coordinate system,
wherein the bus bar frame assembly (<NUM>) includes:
a front bus bar frame (<NUM>) configured to cover a front surface of the cell stack (<NUM>); and
a rear bus bar frame (<NUM>) configured to cover a rear surface of the cell stack (<NUM>),
characterized in that the front bus bar frame (<NUM>) includes a pair of module terminals (T) electrically connected to the cell stack (<NUM>),
wherein, when the pair of foldable side plates (<NUM>, <NUM>) are unfolded, the pair of module terminals (T) provided to the first module (M1) and the pair of module terminals (T) provided to the second module (M2) face each other,
and in that the battery module further comprises:
an upper housing (<NUM>) and a lower housing (<NUM>) coupled to pairs of foldable side plates (<NUM>, <NUM>) to cover upper surfaces and lower surfaces of the first module (M1) and the second module (M2) in a state where the pair of foldable side plates (<NUM>, <NUM>) are unfolded while maintaining pressurization to the first module (M1) and the second module (M2).