Secondary battery pack

A secondary battery pack according to an aspect of the present disclosure includes: a cell assembly including a plurality of secondary batteries; a pack case having an internal space for accommodating the cell assembly; an electrode terminal connected to the cell assembly and protruding to the outside of the pack case; and a terminal cover configured to cover an upper portion and partial side surfaces of the electrode terminal, and to be detachable from the pack case by including a hooking protrusion that is hook-coupled to and released from a stopper that is provided in the pack case. In particular, the terminal cover further includes a jig hole configured to allow a cover separating jig to be inserted from outside to inside, and the hooking protrusion is provided at an internal area of the terminal cover to be released from the stopper when the cover separating jig inserted through the jig hole pushes the hooking protrusion.

TECHNICAL FIELD

The present disclosure relates to a secondary battery pack including a plurality of secondary batteries, and more particularly, to a secondary battery pack configured to cover an electrode terminal to reduce exposure to the outside and also to allow a connection member to be connected to the electrode terminal.

The present application claims priority to Korean Patent Application No. 10-2015-0181751 filed on Dec. 18, 2015 in the Republic of Korea, the disclosure of which is incorporated herein by reference.

BACKGROUND ART

Recently, secondary batteries have been widely used in a medium and/or large-scale device such as a vehicle and a power storage device, as well as a small device such as a portable electronic device. In particular, since carbon-based energy is gradually depleted and concern about environment has been increasing, hybrid cars and electric vehicles are being highlighted worldwide including USA, Europe, Japan, and Korea.

In hybrid cars or electric vehicles, the most important component is a secondary battery pack providing a motor of a vehicle with a driving power. Since a driving power of a hybrid car or an electric vehicle is obtained through charging/discharging of a secondary battery pack, the hybrid car or the electric vehicle has various advantages in various aspects, for example, excellent mileage, no discharge or reduced discharge of pollution materials, etc., and thus, people using the hybrid car or the electric vehicle have been increasing.

A secondary battery pack of a hybrid car or an electric vehicle includes a plurality of secondary batteries, and the plurality of secondary batteries are connected to one another in series or in parallel to improve capacity and output. A general secondary battery pack including the above secondary battery pack for a vehicle includes a cell assembly in which a plurality of secondary batteries are stacked and a pack case accommodating the cell assembly therein. Also, in order to use such a secondary battery pack, the secondary battery pack has to be electrically connected to an external device via a connection member such as a connecting wire or a bus bar, and to do this, the secondary battery pack may include an electrode terminal. In particular, the electrode terminal is likely to protrude from the pack case to an outer part and be exposed in order to be easily coupled to the connection member. Therefore, an end of the connection member is coupled in contact with the electrode terminal and the other end is connected to an external device, e.g., a motor, in a state of extending from the end via an electric wire, and thus, a driving power may be supplied from a battery pack to the motor.

However, there are some problems when an electrode terminal of a secondary battery pack is exposed to an outer part of a pack case. For example, a conductive material such as a bolt, a piece of metal, or an electric wire may contact the electrode terminal, and in this case, an external short-circuit may occur. In addition, the contact of the conductive material may cause damage on the battery pack or an electric system, and moreover, may generate spark that results in fire. Therefore, to address the above problems, there have been attempts to reduce or remove the exposure of the electrode terminal, and a configuration of connecting a connecting wire to the electrode terminal and then covering an outer part of the electrode terminal with a terminal cover is a representative method.

Such a terminal cover is detachably mounted on a pack case in order to perform a rewiring of the electrode terminal and the connecting wire and maintenance while protecting the electrode terminal. As an example, the terminal cover may have a restrictively exposed side surface so as to allow a connecting wire to access, and may be configured to be mounted on an upper surface of the pack case in a bolting manner or a hook manner.

However, according to the bolting manner that is applied to mounting of the terminal cover according to the related art, although a coupling force may be excellent, a bolt has to be fastened and loosened repeatedly and the bolt is likely to contact the electrode terminal during disassembling and assembling processes. On the other hand, according to the hook manner, an assembling process may be simpler and safer than the bolting manner, but a coupling force is weak and an excessive power that may be applied in the disassembling and assembling processes may unintentionally break components.

DISCLOSURE

Technical Problem

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a secondary battery pack capable of minimizing an exposure of an electrode terminal to ensure safety and implementing a robust coupling of a terminal cover while enabling easy attachment and detachment of the terminal cover.

The other objects and advantages of the present disclosure will be apparent from the following description and the exemplary embodiments of the present disclosure. Also, it will be readily understood that the objects and advantages of the present disclosure are realized by the means and combinations thereof set forth in the appended claims.

Technical Solution

In one aspect of the present disclosure, there is provided a secondary battery pack including: a cell assembly including a plurality of secondary batteries; a pack case having an internal space for accommodating the cell assembly; an electrode terminal connected to the cell assembly and protruding to the outside of the pack case; and a terminal cover configured to cover an upper portion and partial side surfaces of the electrode terminal, and to be detachable from the pack case by including a hooking protrusion that is hook-coupled to and released from a stopper that is provided in the pack case.

In particular, the terminal cover may further include a jig hole configured to allow a cover separating jig to be inserted from outside to inside, and the hooking protrusion may be provided at an internal area of the terminal cover to be released from the stopper when the cover separating jig inserted through the jig hole pushes the hooking protrusion.

The pack case may include a terminal cover mounting part having a square-shaped upper surface and four corners, at least one of which is depressed, the electrode terminal may be located on the terminal cover mounting part, and the terminal cover may be coupled to the terminal cover mounting part.

The terminal cover mounting part may include a through hole provided in a vertical direction so that the electrode terminal protrudes to the outside, and the terminal cover may include an upper plate covering an upper portion of the electrode terminal, and side plates partially covering side surfaces of the electrode terminal.

The hooking protrusion may extend downward from the upper plate of the terminal cover, and the stopper may be partially depressed inward from a wall surface of the terminal cover mounting part.

The stopper comprises two stoppers, respectively on two crossing wall surfaces of the terminal cover mounting part, and the hooking protrusion comprises two hooking protrusions corresponding to the two stoppers and the two hooking protrusions may be hook-coupled to the two stoppers in different directions.

The hooking protrusion and the stopper may be configured to be vertically hook-coupled to each other.

An inclined surface that guides the hooking protrusion downward to be hook-coupled to the stopper may be formed on an upper part of the stopper.

The hooking protrusion may include: a supporter spaced a predetermined distance from the stopper in a transverse direction and extending perpendicularly downward from the upper plate of the terminal cover; and a coupling portion curved upward from an end of the supporter in a direction towards the stopper to contact the stopper, and the jig hole may be located above the coupling portion.

The jig hole may be formed in the upper plate to be inclined by a predetermined angle with respect to a vertical direction.

The terminal cover mounting part may include at least one of a protrusion and a groove, and the terminal cover may include at least one of a groove and a protrusion corresponding to the terminal cover mounting part.

The terminal cover may include a concave portion formed by depressing a corner where the two side plates cross each other into an internal area of the terminal cover, and the terminal cover mounting part may include an internal column located at an internal area of the terminal cover based on the concave portion to support the upper plate of the terminal cover, and an external column provided to be inserted in the concave portion in a longitudinal direction from an outer part of the terminal cover.

The electrode terminal may include a positive electrode terminal and a negative electrode terminal, and the terminal cover comprises two terminal covers respectively covering the positive electrode terminal and the negative electrode terminal.

The cover separating jig may include a head and a compressor extending from the head and having a smaller cross-sectional area than the head, and the jig hole may be equal to or greater than a cross-sectional area of the compressor and smaller than a cross-sectional area of the head.

In another aspect of the present disclosure, there is also provided a vehicle including the above-described secondary battery pack.

Advantageous Effects

According to an aspect of the present disclosure, a pack case and a terminal cover may be easily attached to and detached from each other when comparing with the related art, and also a coupling force may be relatively improved, and thus safety of a secondary battery pack may be improved.

In particular, when the terminal cover is separated from the pack case, the terminal cover may be configured to be separated from the pack case when an additional cover separating jig is pushed into a jig hole to a predetermined depth, and thus, anyone may accurately apply a power of an appropriate degree to a hook coupling part and the terminal cover may be safely separated from the pack case without breaking components.

MODE FOR DISCLOSURE

FIG. 1is an assembled perspective view schematically showing a structure of a secondary battery pack according to an embodiment,FIG. 2is a partially exploded perspective view ofFIG. 1, andFIG. 3is a diagram showing a state in which a terminal cover is removed from a state ofFIG. 1.

Referring toFIGS. 1 to 3, a secondary battery pack10according to the present disclosure includes a cell assembly100, a pack case200, an electrode terminal300, and a terminal cover400.

The cell assembly100includes one or more secondary batteries. In particular, in the secondary battery pack10, the cell assembly100may be an assembly including a plurality of secondary batteries. Here, the plurality of secondary batteries may be pouch type secondary batteries. In this case, the pouch type secondary batteries may be configured to be stacked in a direction, e.g., in an up-and-down direction.

In addition, the cell assembly100may further include a stacking frame110. The stacking frame110is an element used to stack the secondary batteries, and holds the secondary batteries to prevent the secondary batteries from moving and is configured to be stackable to guide assembling of the secondary batteries. The stacking frame110may be expressed in other various terms such as a cartridge, etc., and may be configured as a square ring having empty center portion. In this case, four corners of the stacking frame110may be respectively located at an outer circumference of the pouch type secondary battery.

In the present embodiment, the secondary battery pack10may further include a sensing unit500and electrical equipment600.

The sensing unit500transmits sensing information about electric characteristics such as a voltage of the secondary battery to a device such as BMS. The BMS may control the secondary batteries based on voltage information transmitted from the sensing unit500. The sensing unit500may be mounted on the stacking frames110as shown inFIG. 2, so as to be electrically connected to electrode leads of the plurality of secondary batteries.

The electrical equipment600may include at least one of a BMS, a current sensor, a relay, and a fuse. Here, the BMS (battery management system) is a secondary battery management device that controls overall charging/discharging operations of the secondary battery pack10. The BMS is an element generally included in the secondary battery pack10. Also, a current sensor is an element for sensing charging/discharging currents of the secondary battery pack10, and a relay is a switching component for selectively opening/closing charging/discharging current paths through which charging/discharging currents of the secondary battery pack10flow. A fuse is provided on the charging/discharging paths of the secondary battery pack10and blocks flow of the charging/discharging currents when an abnormal situation occurs in the secondary battery pack10. The current sensor, the relay, and the fuse may exchange information with the BMS, and may be controlled by the BMS. The above electrical equipment600may be arranged on an upper portion of the stacking frames110.

The pack case200includes an internal space that is empty therein to accommodate the cell assembly100, the sensing unit500, and the electrical equipment600in the internal space. The pack case200may function as an exterior material of the secondary battery pack10, and thus, the pack case200provides structural stability to the secondary battery pack10and protects the components such as the cell assembly100accommodated therein against external physical elements such as shock, impurities, etc.

In addition, the pack case200may include a lower case220and an upper case210, as shown inFIGS. 1 to 3. Here, the lower case220may have an open upper portion and an accommodation space therein, and the upper case210may be configured to cover the open upper portion of the lower case220. In addition, the lower case220and the upper case210may be coupled to each other when boundaries thereof are coupled to each other via a coupling member such as a bolt.

In the present embodiment, the pack case200has a square-shaped upper surface, two of four corners of which include terminal cover mounting parts210athat are depressed from the upper surface of the pack case200.

As shown inFIGS. 2 and 3, the terminal cover mounting parts210aare provided at the outermost corners on an upper surface of the upper case210, and thus, the terminal cover mounting part210amay have open outer surfaces and inner side surfaces surrounded by wall surfaces having a predetermined height.

In addition, the terminal cover mounting part210aincludes a through hole211formed in a longitudinal direction. The pack case of the present embodiment may be configured so that the electrode terminal300may expose to an outer part of the upper case210via the through hole211of the terminal cover mounting part210awhen the upper case210and the lower case220are coupled to each other.

The electrode terminal300is connected to the cell assembly100to provide a terminal that allows the cell assembly100to be electrically connected to an external device. In more detail, the electrode terminal300may be directly or indirectly connected to electrode leads of the secondary batteries included in the cell assembly100. For example, the electrode terminal300may be electrically connected to the electrode lead of the secondary battery via a bus bar.

Also, the electrode terminal300may be exposed to the outer part of the pack case200as described above, in a state of connecting to the cell assembly100. Two electrode terminals300may be included in the secondary battery pack10. Here, one electrode terminal300may function as a positive electrode terminal and the other electrode terminal300may function as a negative electrode terminal. That is, the electrode terminal300may include a positive electrode terminal and a negative electrode terminal, and in this case, the positive electrode terminal is connected to a positive electrode lead of the secondary battery included in the cell assembly100and the negative electrode terminal may be connected to a negative electrode lead of the secondary battery. Preferably, the electrode terminal300may protrude as shown in the drawing.

According to the configuration of the present disclosure, when a bus bar or a cable is connected to the electrode terminal300of the secondary battery pack10a connecting operation may be easily performed and a connecting structure may be simplified. For example, in a case where the secondary battery pack10is mounted in an electric vehicle, when the secondary battery pack10is to be repaired or replaced, access to the secondary battery pack10may be made downward from an upper portion of the secondary battery pack10. Here, according to the configuration in which the electrode terminal300protrudes upward as in the above embodiment, an operator may easily perform a connecting operation of a cable to the electrode terminal300from the upper portion of the secondary battery pack10.

The terminal cover400is attachable to and detachable from the terminal cover mounting parts210ato cover an upper portion and a part of a side surface of the electrode terminal300. That is, the electrode terminal300may protrude to the outer part of the pack case200, and in this case, the terminal cover400may cover the electrode terminal300except for a part, so that only a part may be exposed outside and remaining part may not be exposed. In addition, an opening part of the terminal cover400may be used as a passage of a cable (not shown) connected to the electrode terminal300.

According to the structure of the terminal cover400, the exposure of the electrode terminal300to the outside may be reduced. Thus, problems caused by the exposure of the electrode terminal300, e.g., contacting of a metal material to the electrode terminal300and occurrence of an internal short-circuit, spark, a fire, etc., may be effectively prevented.

FIG. 4is a partially enlarged perspective view of a part A ofFIG. 1,FIG. 5is a perspective view showing a state in which the terminal cover400is separated inFIG. 4,FIG. 6is a top view ofFIG. 4, andFIG. 7is a cross-sectional view taken along a line I-I′ ofFIG. 6.

Referring toFIGS. 4 to 7, the configuration of the terminal cover400will be described in more detail, that is, the terminal cover400includes an upper plate410covering an upper part of the electrode terminal300and side plates420partially covering side surfaces of the electrode terminal300. When the terminal cover400is coupled to the terminal cover mounting parts210of the upper case210, the electrode terminal300may be shielded except for a front side surface and a right side surface thereof in the drawings. Here, the front side surface denotes a side surface right in front of the electrode terminal300and the right side surface is a side surface at right of the electrode terminal300when the secondary battery pack10is seen in a direction of an arrow B as shown inFIG. 1. A rear side surface and a left side surface of the electrode terminal300may be blocked by wall surfaces of the terminal cover mounting part210a.

Each side plate420of the terminal cover400includes a cut portion421that is partially cut. In particular, as shown inFIG. 4, two cut portions421are provided in the terminal cover400in different directions. One of the two cut portions421may be used as a passage for the cable wiring, and at this time, the operator may select one of the cut portions421, which is suitable for the operation of wiring the cable. For example, a location of another secondary battery pack10or an external device that has to be electrically connected to the secondary battery pack10in the drawings may be relatively changed, and thus an accessing direction or an extending direction of the cable for the electric connection between them may also vary. As an example, the terminal cover400includes the cut portions421respectively in the front side surface and the right side surface of the electrode terminal300in order to effectively deal with the variation in the cable connecting structure.

In the present embodiment, the upper plate410of the terminal cover400is formed as a square corresponding to an upper area of the terminal cover mounting part210a, and the side plates420correspond to two outer surfaces and have a height corresponding to that of the wall surface. The terminal cover400may be attached to/detached from the terminal cover mounting part210ain a longitudinal direction.

Hereinafter, attaching and detaching structure between the terminal cover400and the upper case210will be described in more detail below with reference toFIGS. 4 to 7.

The terminal cover mounting part210aand the terminal cover400respectively include a stopper212and a hooking protrusion430that are configured to hook-coupled to each other. The stopper212may be provided by partially depressing inward the wall surface of the terminal cover mounting part210a, as shown inFIG. 5. In addition, an inclined surface213is formed right on the stopper212, and the inclined surface213guides the hooking protrusion430downward to be hook-coupled by the stopper212when the terminal cover400is attached.

The hooking protrusion430is located at an inner space of the side plates420of the terminal cover400to extend downward from the upper plate410of the terminal cover400, and may be configured to be hooked by the stopper212from upper and lower portions of each other.

As shown inFIG. 7, the hooking protrusion430may include a supporter431spaced a predetermined distance d from the stopper212in a transverse direction and extending vertically downward from the upper plate410of the terminal cover400, and a coupling portion432curved upward from an end of the supporter431in a direction towards the hooking protrusion212to contact the stopper212. The hooking protrusion430is formed on the upper plate410of the terminal cover400as a cantilever, and the supporter431is elastic to be curved within a predetermined range by an external force.

Two stoppers212and two hooking protrusions430may be respectively provided on the terminal cover mounting part210aand the terminal cover400, and directions in which the two stoppers430are hook-coupled by the corresponding hooking protrusions212are different from each other. For example, two stoppers212may be respectively formed on two crossing wall surfaces of the terminal cover mounting part210a, and one of the two hooking protrusions430corresponding to the stoppers212is coupled to one stopper212in an X-axis direction ofFIG. 4and the other hooking protrusion430is coupled to the other stopper212in a Y-axis direction ofFIG. 4. Therefore, the hook-coupled states in the X-axis and Y-axis directions have to be unhooked at the same time to separate the terminal cover400. That is, the terminal cover400may be stably fixed to the upper case210to protect the electrode terminal300.

In addition, the present disclosure is not limited to the example, in which one stopper212is provided on one side wall of the terminal cover mounting part210aand one hooking protrusion430corresponds to the stopper212. That is, one or more pairs of stoppers212and hooking protrusions430may be respectively coupled to each other in different directions.

In the present embodiment, the terminal cover mounting part210aincludes at least one of a protrusion and a groove, and the terminal cover400includes at least one of a groove and a protrusion corresponding to those of the terminal cover mounting parts210a.

For example, as shown inFIGS. 4 and 5, the terminal cover mounting part210amay further include first protrusions P1protruding from the external surface thereof, and second grooves H1formed as concavo-convex structures along upper boundaries of the wall surfaces. In addition, first grooves H2engaged with the first protrusions and second protrusions engaged with the second grooves may be respectively provided in lower ends of the side plates420and opposite side surfaces of the terminal cover400, which are not seen in the drawings.

Through the engagement or concavo-convex coupling structure between the protrusions and the grooves of the terminal cover mounting part210aand the terminal cover400, the terminal cover400may be held by the upper case210and may be restricted to move back and forth, and to left and right.

Also, the terminal cover400may further include a concave portion440at a corner where the side plates420cross each other. Here, the concave portion440has a structure of being depressed or curved towards the inner portion of the terminal cover400between the two side plates420.

In addition, the terminal cover mounting part210aincludes an internal column214that is located in an internal area of the terminal cover400based on the concave portion440to support the upper plate410of the terminal cover400, and an external column215provided to be inserted to the concave portion440in a longitudinal direction at an outer part of the terminal cover400.

The internal column214supports the upper plate410of the terminal cover400at the internal area of the terminal cover400to provide the terminal cover400with mechanical supporting force, and the external column215guides the mounting operation of the terminal cover400in the longitudinal direction and supports the terminal cover400at the outer part by being inserted into the internal space of the concave portion440to prevent the terminal cover400from moving in the transverse direction as shown inFIG. 6.

Also, the terminal cover400may further include a jig hole411in the upper plate410of the terminal cover400. The jig hole411is a hole provided to guide insertion of a cover separating jig700from the outer part of the terminal cover400into the terminal cover400. Here, the cover separating jig700(seeFIG. 9) may be a bar-shaped tool for releasing the hooking protrusion430that has been hook-coupled in the internal area of the terminal cover400from the stopper212.

For example, the hooking protrusion430may be separated from the stopper212when it is pushed by the cover separating jig700that is inserted through the jig hole411, and the engagement in the longitudinal direction may be released. That is, two jig holes411are formed in the upper plate410of the terminal cover400, and the cover separating jig700is inserted into each of the jig holes411to release the hook-coupling state of the hooking protrusion430from the stopper212and then the terminal cover400is lifted to be detached from the upper case210.

FIGS. 8 and 9are partially enlarged views showing the terminal cover400before and after inserting the cover separating jig700.

Referring toFIGS. 7 to 9, the jig hole411may be located above a coupling portion432. The cover separating jig700may be introduced to the internal space of the terminal cover400, that is, a space between the stopper212and the supporter431of the hooking protrusion430, through the jig hole411.

In addition, as shown inFIGS. 7 and 8, the jig hole411may be formed in the upper plate410of the terminal cover400to be inclined by a predetermined angle (θ) with respect to a vertical direction. For example, the upper plate410of the terminal cover400has a predetermined thickness, and the upper plate410is perforated in an inclined state by a predetermined angle to form the jig hole411. Here, the inclined direction of the jig hole411may face the supporter431of the hooking protrusion430.

According to the structure of the jig hole411, as shown inFIGS. 8 and 9, the cover separating jig700may be inserted in a direction C to be inclined by a predetermined angle with respect to the upper plate410, and the hooking protrusion430is elastically curved in a direction D and released from the stopper212when the cover separating jig700pushes the hooking protrusion430.

The cover separating jig700may include a compressor720that may pass through the jig hole411and a head710that may not be inserted to the jig hole411. That is, the compressor720is integrally formed with the head710, and has a smaller cross-sectional area than the head710. In addition, the jig hole411may have a diameter that only allows the compressor720to be inserted therein.

Also, a length of the compressor720may be determined to correspond to an elastic deformation value of the hooking protrusion430, which makes the hooking protrusion430separated from the stopper212. By restricting the length and the insertion depth of the compressor720, an excessive power may not be applied to the hooking protrusion430, and thereby damage on the components may be prevented.

As described above, according to the configuration of the terminal cover400according to the present disclosure, the pack case200and the terminal cover400may be easily attached to/detached from each other and a coupling force therebetween may be improved comparing with the related art, and thus, safety of the secondary battery pack10may be improved.

In particular, when the operator pushes the cover separating jig700into the jig hole411to a predetermined depth, the coupling state between the hooking protrusion430of the terminal cover400and the stopper212of the terminal cover mounting part210ais to be released, and accordingly, a power having an accurate and appropriate strength may be applied to the coupling portion. Therefore, anyone may separate the terminal cover400from the pack case200without concerning about the breakdown of the components.

In addition, a vehicle according to the present disclosure may include the secondary battery pack10according to the present disclosure. The secondary battery pack10may be applied to a vehicle such as an electric vehicle or a hybrid car, and moreover, may be also applied to information technology (IT) products.

On the other hand, it is obvious to one of ordinary skill in the art that the terms used to indicate the direction as described herein, such as ‘upper’, ‘lower’, ‘right’ and ‘left’, are only for convenience of description, and may be differently expressed depending on a viewing position of a viewer or a location where an object is placed.