Patent Description:
In the case of a battery module using an indirect water cooling method using cooling water, because cooling water does not directly contact a battery cell but indirectly contacts the battery cell through a module housing in which the battery cell is accommodated, there is a limit to its cooling performance. Also, because a cooling device such as a separate heat sink should be provided outside the module housing to form a passage for cooling, a volume of the battery module is inevitably increased, which may cause loss in terms of energy density.

In order to solve the problems of the indirect water cooling method, there is a need to develop a battery module having a cooling structure in which insulating oil for cooling may be directly introduced into a module housing and may directly contact a battery cell.

In the case of a battery module having a direct cooling structure using insulating oil, it is very important to secure a fluid passage structure for efficient cooling, and maintain airtightness so that insulating oil does not leak to the outside of a module housing and an end plate. Document <CIT> is relevant prior art.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to securing a path through which insulating oil introduced into a module housing passes through a bus bar frame assembly, smoothly moves toward a cell stack assembly, and smoothly flows in a longitudinal direction of a battery module.

However, the technical purpose to be solved by the present disclosure is not limited to the above, and other objects not mentioned herein will be clearly understood by one of ordinary skill in the art from the following disclosure.

In one aspect of the present disclosure, there is provided a battery module according to independent claim <NUM>.

The cooling fin may include: a body contact portion located between adjacent battery cells; and an edge cover portion bent at any one of an upper end and a lower end of the body contact portion to cover an edge of the battery cell.

The front bus bar frame assembly and the rear bus bar frame assembly may include a plurality of insulating oil holes formed at positions corresponding to insulating oil passages formed between the module housing and an edge of the battery cell and between the edge cover portion and an edge of the battery cell.

Insulating oil introduced through the insulating oil inlet into the module housing may pass through the insulating oil hole formed in the front bus bar frame assembly and may be introduced into the insulating oil passage.

The insulating oil passing through the insulating oil passage may pass through the insulating oil hole formed in the rear bus bar frame assembly, and may be discharged to outside of the module housing through the insulating oil outlet.

The front bus bar frame assembly and the rear bus bar frame assembly may include guide ribs respectively formed at an upper end and a lower end and extending toward the cell stack assembly.

The cooling fin may further include a pair of fixing portions each having a shape corresponding to the guide rib, formed on both end portions of the edge cover portion in a longitudinal direction of the edge cover portion, and each coupled to the guide rib.

The battery module may further include a pair of terminal assemblies each including an external terminal located outside the front sealing plate, and a stud passing through the front sealing plate and configured to electrically connect the external terminal to the battery cell.

The front bus bar frame assembly may include: a bus bar frame; a plurality of bus bars fixed to the bus bar frame, and connected to an electrode lead of the battery cell; and a pair of internal terminals each fixed to the bus bar frame, and connected to an electrode lead of the battery cell located at an outermost position from among the battery cells provided in the cell stack assembly.

The terminal assembly may further include a terminal spacer inserted into a terminal hole formed in the front sealing plate, wherein the stud is fixed to the internal terminal and passes through the terminal spacer.

The terminal assembly may further include a fastening nut fastened to the stud passing through the terminal spacer and the external terminal and configured to closely fix the external terminal to the terminal spacer.

The terminal assembly may further include a first O-ring covering an outer circumferential surface of the terminal spacer and located between an inner surface of the front sealing plate and the internal terminal.

The stud may be press-fitted by passing through the internal terminal, wherein the terminal assembly further includes a second O-ring located around the stud and located between the internal terminal and the bus bar frame.

In another aspect of the present disclosure, there are also provided a battery pack and a vehicle including the battery module.

According to an aspect of the present disclosure, insulating oil introduced into a module housing may pass through a bus bar frame assembly, may smoothly move toward a cell stack assembly, and may smoothly flow in a longitudinal direction of a battery module in the module housing. Also, according to an aspect of the present disclosure, leakage of insulating oil flowing inside a module housing may be effectively prevented.

Referring to <FIG> and <FIG>, a battery module according to an embodiment of the present disclosure includes a sub-module <NUM>, a module housing <NUM>, a front sealing plate <NUM>, a rear sealing plate <NUM>, and a pair of terminal assemblies <NUM>, and may further include a front end plate <NUM> and a rear end plate <NUM>.

Referring to <FIG>, the sub-module <NUM> includes a cell stack assembly <NUM>, a front bus bar frame assembly 120A, and a rear bus bar frame assembly 120B.

The cell stack assembly <NUM> includes a plurality of battery cells <NUM> and a plurality of cooling fins <NUM> located between adjacent battery cells <NUM>, and may further include at least one buffer pad <NUM> located between adjacent battery cells <NUM>. The battery cell <NUM>, the cooling fin <NUM>, and the buffer pad <NUM> are stacked upright in a direction perpendicular to the ground (surface parallel to an X-Y plane) to constitute one cell stack assembly <NUM>.

The battery cell <NUM> may be a pouch-type battery cell including a pair of electrode leads 111a drawn out in opposite directions in a longitudinal direction (direction parallel to an X-axis).

Referring to <FIG>, the cooling fin <NUM> includes a body contact portion 112a located between adjacent battery cells <NUM> and an edge cover portion 112b bent at any one of an upper end and a lower end of the body contact portion 112a to cover an edge of the battery cell <NUM>. Edges of the battery cell <NUM> refer to both side surfaces of a body of the battery cell <NUM> in a width direction, that is, in a height direction (direction parallel to a Z-axis) of the battery module. Also, the cooling fin <NUM> may further include a pair of fixing portions 112c formed on both end portions of the edge cover portion 112b in a longitudinal direction (direction parallel to the X-axis) of the edge cover portion 112b.

The body contact portion 112a is located between bodies of a pair of adjacent battery cells <NUM> and directly contacts the bodies of the battery cells <NUM>. The body contact portion 112a is configured to rapidly conducts heat generated from a body of the battery cell <NUM>, that is, a region where an electrode assembly (not shown) is accommodated, in a width direction of the cooling fin <NUM>, that is, the height direction (direction parallel to the Z-axis) of the battery module, toward the edge cover portion 112b. As such, the heat conducted toward the edge cover portion 112b moves in a longitudinal direction (direction parallel to the X-axis) of the battery module due to insulating oil flowing through an insulating oil passage P formed between the edge of the battery cell <NUM> and the edge cover portion 112b and is discharged to the outside of the battery module.

The edge cover portion 112b may not only form the insulating oil passage P as described above but also, when external impact is applied and the cell stack assembly <NUM> moves in a vertical direction (direction parallel to the Z-axis) in the module housing <NUM>, may absorb the external impact.

The fixing portion 112c has a shape corresponding to that of a guide rib 121b described below. The fixing portion 112c may be coupled to the guide rib 121b, to guide fastening between the bus bar frame assembly 120A, 120B and the cell stack assembly <NUM> including the cooling fin <NUM>.

The buffer pad <NUM> may be located between adjacent battery cells <NUM> and may absorb volume expansion according to swelling of the battery cells <NUM>.

The front bus bar frame assembly 120A and the rear bus bar frame assembly 120B may be coupled to a side and the other side of the cell stack assembly <NUM> in a longitudinal direction of the cell stack assembly <NUM> to electrically connect the plurality of battery cells <NUM>. The front bus bar frame assembly 120A and the rear bus bar frame assembly 120B have substantially the same structure except that the front bus bar frame assembly 120A includes an internal terminal <NUM> and the rear bus bar frame assembly 120B does not include the internal terminal <NUM>. Accordingly, a detailed description of a structure of the rear bus bar frame assembly 120B will be omitted, and a structure of the front bus bar frame assembly 120A will be mainly described.

Referring to <FIG>, the front bus bar frame assembly 120A includes a bus bar frame <NUM>, a plurality of bus bars <NUM>, and a pair of internal terminals <NUM>. The bus bar frame <NUM> covers a side of the cell stack assembly <NUM> in the longitudinal direction (direction parallel to the X-axis) of the cell stack assembly <NUM>.

The bus bar frame <NUM> includes a plurality of insulating oil holes 121a. The insulating oil hole 121a functions as a path through which insulating oil introduced through an inlet P1 provided at the front sealing plate <NUM> into the module housing <NUM> may pass through the bus bar frame <NUM> and may be introduced into the cell stack assembly <NUM>.

As shown in <FIG> and <FIG>, the insulating oil passage P is formed between the module housing <NUM> and an edge of the battery cell <NUM>, and between the edge cover portion 112b and an edge of the battery cell <NUM>. Accordingly, the insulating oil hole 121a is formed at a position corresponding to the insulating oil passage P formed between the module housing <NUM> and the edge of the battery cell <NUM> and between the edge cover portion 112b of the cooling fin <NUM> and the edge of the battery cell.

Insulating oil introduced through the insulating oil hole 121a formed in the front bus bar frame assembly 120A into the cell stack assembly <NUM> moves in an arrow direction (see <FIG> and <FIG>) through the insulating oil passage P toward the rear bus bar frame assembly 120B. The insulating oil moving toward the rear bus bar frame assembly 120B is introduced through the insulating oil hole 121a formed in the rear bus bar frame 120B into the rear sealing plate <NUM>, and is discharged to the outside of the battery module through an outlet P2 provided at the rear sealing plate <NUM>. In this process, the insulating oil directly contacts the electrode lead 111a of the battery cell <NUM>, and indirectly contacts a body of the battery cell <NUM>, to cool the battery cell <NUM>.

The bus bar <NUM> is fixed to the bus bar frame <NUM>, and is coupled to the electrode lead 111a drawn out through a lead slit formed in the bus bar frame <NUM> to electrically connect the plurality of battery cells <NUM>.

The internal terminal <NUM> is fixed to the bus bar frame <NUM>, and is coupled to the electrode lead 111a of the battery cell <NUM> located at an outermost position from among the battery cells <NUM> provided in the cell stack assembly <NUM>. The internal terminal <NUM> functions as a high-potential terminal. The internal terminal located on a side of the bus bar frame <NUM> in a longitudinal direction of the bus bar frame <NUM> functions as a positive electrode high-potential terminal, and the internal terminal <NUM> located on the other side of the bus bar frame <NUM> in the longitudinal direction of the bus bar frame <NUM> functions as a negative electrode high-potential terminal. The internal terminal <NUM> is electrically connected to an external terminal <NUM> described below (see <FIG> and <FIG>).

Referring to <FIG>, the bus bar frame <NUM> of the front bus bar frame assembly 120A and the bus bar frame <NUM> of the rear bus bar frame assembly 120B include a plurality of guide ribs 121b formed at an upper end and a lower end in the longitudinal direction (direction parallel to a Y-axis). The guide rib 121b extends toward the cell stack assembly <NUM>. The guide rib 121b is formed at a position corresponding to the fixing portion 112c of the cooling fin <NUM>.

As described above, the fixing portions 112c having a shape corresponding to the guide ribs 121b are formed on both end portions of the edge cover portion of the cooling fin <NUM> in the longitudinal direction (direction parallel to the X-axis) of the edge cover portion 112b. A movement of the cooling fin <NUM> in the vertical direction (direction parallel to the Z-axis) and the longitudinal direction (direction parallel to the X-axis) is limited by the guide rib 121b and the fixing portion 112c. Accordingly, when the front bus bar frame assembly 120A and the rear bus bar frame assembly 120B are coupled to the cell stack assembly <NUM>, a coupling position may be guided, thereby increasing assembly convenience.

Referring to <FIG>, the sub-module <NUM> including the cell stack assembly <NUM>, the front bus bar frame assembly 120A, and the rear bus frame assembly 120B is accommodated in the module housing <NUM>. The module housing <NUM> has a shape in which a side and the other side of the module housing <NUM> in a longitudinal direction (direction parallel to the X-axis) are open.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the front sealing plate <NUM> covers an opening portion formed on a side of the module housing <NUM> in the longitudinal direction (direction parallel to the X-axis) of the module housing <NUM>. The front sealing plate <NUM> includes the insulating oil inlet P1 through which insulating oil is introduced. In order to prevent leakage of insulating oil, a gasket G may be located between an edge surface of the front sealing plate <NUM> and an inner surface of the module housing <NUM> (see <FIG>).

The front sealing plate <NUM> includes a pair of terminal holes 300a through which a component for electrical connection between the external terminal <NUM> described below and the internal terminal <NUM> provided in the front bus bar frame assembly 120A may pass. The terminal hole 300a is formed at a position corresponding to the internal terminal <NUM>.

Referring to <FIG>, the rear sealing plate <NUM> covers an opening portion on the other side of the module housing <NUM> in the longitudinal direction (direction parallel to the X-axis) of the module housing <NUM>, and includes the insulating oil outlet P2 through which insulating oil is discharged. Like in the front sealing plate <NUM>, in order to prevent leakage of insulating oil, a gasket G may be located between an edge surface of the rear sealing plate <NUM> and an inner surface of the module housing <NUM>.

The front sealing plate <NUM> and the rear sealing plate <NUM> may be formed of an insulating resin for electrical insulation.

Referring to <FIG> and <FIG>, the terminal assembly <NUM> includes the external terminal <NUM> located outside the front sealing plate <NUM> and a stud <NUM> configured to electrically connect the external terminal <NUM> to the battery cell <NUM>. The stud <NUM> is fixed to the internal terminal <NUM>. The stud <NUM> may pass through the internal terminal <NUM> and may be fixed to the internal terminal <NUM> by using a press-fitting method. The stud <NUM> fixed to the internal terminal <NUM> is drawn outward through the terminal hole 300a formed in the front sealing plate <NUM> and is coupled to the external terminal <NUM>.

The terminal assembly <NUM> may further include a terminal spacer <NUM> having a ring shape and inserted into the terminal hole 300a formed in the front sealing plate <NUM>. The terminal spacer <NUM> may be formed of a metal material. When the terminal spacer <NUM> is provided, the stud <NUM> passes through the terminal pacer <NUM>.

The terminal assembly <NUM> may further include a fastening nut <NUM> for fastening the external terminal <NUM> to the stud <NUM>. The fastening nut <NUM> is fastened to the stud <NUM> passing through the terminal spacer <NUM> and a fastening portion <NUM> of the external terminal <NUM>, to closely fix the fastening portion <NUM> of the external terminal <NUM> to the terminal spacer <NUM>. Accordingly, the internal terminal <NUM> and the external terminal <NUM> are electrically connected to each other through the terminal spacer <NUM>.

The terminal assembly <NUM> may further include a first O-ring <NUM> covering an outer circumferential surface of the terminal spacer <NUM> and located between an inner surface of the front sealing plate <NUM> and the internal terminal <NUM>. Referring to <FIG> and <FIG>, the first O-ring <NUM> prevents insulating oil introduced into a space between the front sealing plate <NUM> and the bus bar frame <NUM> from leaking to the outside of the front sealing plate <NUM> through a space between an inner surface of the insulating oil hole 300a and the terminal spacer <NUM>.

Also, the terminal assembly <NUM> may further include a second O-ring <NUM> located around the stud <NUM> press-fitted to the internal terminal <NUM> and exposed to a space between the internal terminal <NUM> and the bus bar frame <NUM>, the second O-ring <NUM> being located between the internal terminal <NUM> and the bus bar frame <NUM>. The second O-ring <NUM> prevents insulating oil introduced into a space between the front sealing plate <NUM> and the bus bar frame <NUM> from leaking to the outside of the front sealing plate <NUM> through a space between the internal terminal <NUM> and the stud <NUM> and a space between an inner surface of the terminal spacer <NUM> and the stud <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the front end plate <NUM> covers the front sealing plate <NUM> and is fixed to the module housing <NUM>. The rear end plate <NUM> covers the rear sealing plate <NUM> and is fixed to the module housing <NUM>.

The front end plate <NUM> includes a terminal exposing portion 500a configured to expose a connecting portion <NUM> of the external terminal <NUM> to be exposed to the outside of the front end plate <NUM> and an inlet exposing portion 500b configured to expose the insulating oil inlet P1 to be exposed to the outside of the front end plate <NUM>. The rear end plate <NUM> includes an outlet exposing portion 600b configured to expose the insulating oil outlet P2 to be exposed to the outside of the rear end plate <NUM>.

When the front end plate <NUM> and the rear end plate <NUM> are applied to the battery module according to the present disclosure, a gasket for preventing leakage of insulating oil may be applied to a coupling portion between the front end plate <NUM> and the module housing <NUM> and a coupling portion between the rear end plate <NUM> and the module housing <NUM>.

Claim 1:
A battery module comprising:
a sub-module (<NUM>) comprising a cell stack assembly (<NUM>) comprising a plurality of battery cells (<NUM>) and a cooling fin (<NUM>) located between adjacent battery cells (<NUM>), a front bus bar frame assembly (120A) coupled to a side of the cell stack assembly (<NUM>) in a longitudinal direction (X) of the cell stack assembly (<NUM>), and a rear bus bar frame assembly (120B) coupled to the other side of the cell stack assembly (<NUM>) in the longitudinal direction (X) of the cell stack assembly (<NUM>);
a module housing (<NUM>) in which the sub-module (<NUM>) is accommodated;
a front sealing plate (<NUM>) covering an opening portion formed on a side of the module housing (<NUM>) in a longitudinal direction (X) of the module housing (<NUM>) and comprising an insulating oil inlet (P1); and
a rear sealing plate (<NUM>) covering an opening portion formed on the other side of the module housing (<NUM>) in the longitudinal direction (X) of the module housing (<NUM>) and comprising an insulating oil outlet (P2),
characterized in that the cooling fin (<NUM>) comprises:
a body contact portion (112a) located between adjacent battery cells (<NUM>); and
an edge cover portion (112b) bent at any one of an upper end and a lower end of the body contact portion (112a) to cover an edge of one of the battery cells (<NUM>),
wherein the body contact portion (112a) directly contact bodies of the battery cells (<NUM>),
wherein insulating oil passages (P) are formed between the module housing (<NUM>) and an edge of the battery cell (<NUM>) and between the edge cover portion (112b) and the edge of the battery cell (<NUM>).