A battery module including a bonding pin for connecting to a bus bar and a battery pack including the battery module

Abstract

A battery module according to the present invention includes: battery cells that are connected in series with each other or connected in series and in parallel; a plurality of bus bars that are connected to corresponding electrode leads of the battery cells; and a voltage sensing member having sensing portions respectively connected to the bus bars, wherein each of the plurality of bus bars has a pin hole that penetrates each bus bar in a thickness direction, and each of the sensing portions has a joining pin that is configured to be inserted into and released from the pin hole.

Description

Technical Field

[0001] The present disclosure relates to a battery module, and more particularly, to a battery module and a battery pack including the battery module, in which a connection structure between a bus bar and a voltage sensing member required for sensing the voltage of battery cells in the battery module is improved.

[0002] This application claims priority to Korean Patent Application No. 10-2020-0073793, filed in Korea on June 17, 2020, the disclosure of which is incorporated herein by reference. Background Art

[0003] A semi-permanent battery that converts electrical energy into chemical energy and can be repeatedly charged and discharged is called a secondary battery, as distinguished from a primary battery that cannot be used again after one use.

[0004] Secondary batteries include lithium secondary batteries, nickel-cadmium (Ni-Cd) batteries, lead-acid batteries, nickel-metal hydride (Ni-MH) batteries, zinc-air batteries, alkaline manganese batteries, etc. Among them, lead-acid batteries and lithium secondary batteries are the most actively commercialized secondary batteries.

[0005] In particular, lithium secondary batteries are actively used as electric vehicle batteries because lithium secondary batteries have a high energy storage density, a light weight, and a compact size, and have advantages such as excellent safety, a low discharge rate, and a long lifespan. For reference, depending on the manufacturing shape of lithium secondary batteries, lithium secondary batteries are generally classified into cylindrical, rectangular, and pouch types, and are also used in ESS batteries and other electrical devices as well as electric vehicle batteries.

[0006] Currently, it is not possible to obtain sufficient power to drive an electric vehicle by using only one lithium secondary battery (cell). In order to apply secondary batteries as an energy source for electric vehicles, a battery module in which a plurality of lithium-ion battery cells are connected in series and / or in parallel must be constructed, and a battery pack including a BMS (Battery Management System), a cooling system, a BDU (Battery Disconnect Unit), and a wiring harness for generally connecting the battery modules in series and functionally maintaining them is also constructed.

[0007] Meanwhile, as shown in Figure 1 , if the battery module is configured as a pouch-type secondary battery cell, the electrode leads 1a, 1b of the pouch-type secondary battery cell are welded to the bus bar 3. The bus bar 3 is located at the front surface of the battery module or at the front and rear surfaces of the battery module, and a plurality of electrode leads 1a, 1b are welded to the bus bar 3 in a one-to-one relationship, thereby connecting the secondary battery cells in series and in parallel.

[0008] The voltage information of the secondary battery cells in the battery module is transmitted to the BMS through the voltage sensing members 5 connected to each bus bar 3, and the BMS monitors the state of each secondary battery cell based on the voltage information to control the charging / discharging of the secondary battery cells.

[0009] The voltage sensing members 5 employ a wire harness, FFC (Flexible Flat Cable), FPCB (Flexible Printed Circuit Board), etc. Conventionally, the voltage sensing member 5 and the bus bar 3 are electrically connected in the following manner: compressing a metal terminal to the end of the voltage sensing member 5 and laser welding the metal terminal to the bus bar 3. However, laser welding is expensive and difficult in terms of quality control. Moreover, if the sensing member is defective, it is not possible to perform rework or replacement only on the sensing member. In particular, if the secondary battery cell is even welded to the bus bar, there is a drawback that the secondary battery cell must also be discarded.

[0010] Accordingly, there is a need for a connection method between the bus bar and the sensing member that is easier to control quality than the prior art. SUMMARY OF THE INVENTION

[0011] TECHNICAL PROBLEM

[0012] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure aims to provide a battery module that is configured to easily and quickly connect a bus bar and a voltage sensing member and allows rework if necessary.

[0013] These and other objects and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Moreover, it will be readily understood that the objects and advantages of the present disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0014] TECHNICAL SOLUTION

[0015] The following are various embodiments of the present disclosure for achieving the above object.

[0016] In one aspect of the present disclosure, there is provided a battery module including: a plurality of battery cells connected in series or in series and in parallel; a plurality of bus bars connected to corresponding electrode leads of the battery cells; and a voltage sensing member having sensing portions respectively connected to the bus bars, wherein each of the plurality of bus bars has a pinhole penetrating each bus bar in the thickness direction, and each of the sensing portions has a solder pin configured to be inserted into and released from the pinhole.

[0017] The bonding pin may include: a base portion attached to one surface of the sensing portion; and a hole insertion portion configured to extend in a direction orthogonal to the base portion and disposed to be inserted into the pin hole.

[0018] The hole insertion portion may include a first post and a second post formed to extend parallel to each other.

[0019] Each of the first post and the second post may have a hook-shaped end, and each of the hook-shaped ends may pass through the pin hole and be hooked to the rear surface of the bus bar.

[0020] The pin hole may include: a first hole region formed to have a diameter gradually decreasing from the front surface of the bus bar to a predetermined depth; and a second hole region connected to an end point of the first hole region and formed to have a constant diameter to the rear surface of the bus bar.

[0021] The base portion may be formed in a plate shape with a predetermined thickness and have at least one side strip formed to protrude from the surface of the base portion.

[0022] The at least one side strip may be provided in plurality, and among the plurality of side strips, at least two side strips may be symmetrically provided based on the hole insertion portion.

[0023] The sensing portion may further include a bonding portion welded and electrically connected to the base portion.

[0024] The voltage sensing member may be formed of an FFC (Flexible Flat Cable) or an FPCB (Flexible Printed Circuit Board).

[0025] In another aspect of the present disclosure, there is also provided a battery pack including the above-described battery module.

[0026] Advantageous Effects

[0027] The battery module according to the present disclosure provides the following effects.

[0028] In the battery module of the present disclosure, the bonding pin is mounted to the sensing portion of the voltage sensing member. Since the bus bar and the sensing portion are configured to be connected by inserting the bonding pin into the pin hole of the bus bar, compared with the conventional welding method, the corresponding task can be performed quickly and easily without an expert, thereby ensuring easy quality control.

[0029] In addition, the bonding pin of the battery module of the present disclosure can be removed from the bus bar by using a jig. Therefore, if the voltage sensing member is defective, rework can be performed.

[0030] The effects of the present disclosure are not limited to the above, and from the present specification and the drawings, those skilled in the art can clearly understand the effects not mentioned herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as limited to the drawings.

[0032] Figure 1 is a partial perspective view showing a part of a conventional battery module.

[0033] Figure 2 is a perspective view showing a battery module according to an embodiment of the present disclosure.

[0034] Figure 3 is a view showing a sensing unit and bonding pins according to an embodiment of the present disclosure.

[0035] Figure 4 is a view showing an example in which bonding pins are mounted to Figure 3 the sensing unit.

[0036] Figure 5 and Figure 6 is a view showing an assembly process between a bus bar and a sensing unit according to an embodiment of the present disclosure.

[0037] Figure 7 is a cross-sectional view taken along line I-I’ of Figure 6 ...

[0038] Figure 8 is corresponding to Figure 7 to show a modified example of a pin hole. DETAILED DESCRIPTION

[0039] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the description presented herein is merely a preferred example for illustration and is not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalents and modifications can be made thereto without departing from the scope of the present disclosure.

[0040] The embodiments disclosed herein are provided to more perfectly explain the present disclosure. Therefore, for better understanding, in the drawings, the shapes, sizes, etc. of components may be exaggerated, omitted, or simplified. Therefore, the sizes and ratios of components in the drawings do not exactly reflect the actual sizes and ratios.

[0041] Figure 2 is a perspective view showing a battery module according to an embodiment of the present disclosure, Figure 3 is a view showing a sensing unit and bonding pins according to an embodiment of the present disclosure, and Figure 4 is a view showing an example of the bonding pins being mounted to Figure 3 the sensing unit.

[0042] Referring to these drawings, a battery module 100 according to an embodiment of the present disclosure includes a cell stack 10, a bus bar frame assembly 20, a plurality of bus bars 30, and a voltage sensing member 40.

[0043] The cell stack 10 can be regarded as an aggregate of battery cells. For example, the battery cells can be stacked in the left - right direction and stand upright in the vertical direction to form the cell stack 10. As the battery cells, pouch - type battery cells can be applied. The battery cells of this embodiment are two - way lead - type pouch - type battery cells in which a positive electrode lead and a negative electrode lead are located on opposite sides.

[0044] The pouch - type battery cell can include an electrode assembly, an electrolyte, and a pouch exterior member for encapsulating the electrode assembly and the electrolyte.

[0045] Each electrode plate of the electrode assembly includes an electrode tab, and at least one electrode tab can be connected to the electrode lead 11. The electrode lead 11 can be exposed from the inside of the pouch exterior member to the outside and function as an electrode terminal of the battery cell.

[0046] The pouch exterior member can be configured to include a metal thin film, such as aluminum foil, to protect internal components (such as the electrode assembly and the electrolyte), supplement the electrochemical properties of the electrode assembly and the electrolyte, and improve heat dissipation. The aluminum foil can be interposed between an insulating layer formed of an insulating material and an internal bonding layer to ensure electrical insulation.

[0047] The bus bar frame assembly 20 is a component that supports the cell stack 10 and forms a place for installing the plurality of bus bars 30. The bus bar frame assembly 20 includes a top frame 21, a front frame 22, and a rear frame 23.

[0048] The top frame 21 can be set in the form of a plate having an area that can cover the entire cell stack 10 from the top of the cell stack 10. A part of the voltage sensing member 40 can be placed between the top frame 21 and the cell stack 10. As the voltage sensing member 40, an FFC (flexible flat cable) or an FPCB (flexible printed circuit board) can be used.

[0049] The front frame 22 and the rear frame 23 are plate-shaped bodies having areas that can respectively cover the front surface and the rear surface of the battery stack 10, and may include: slits for allowing the electrode leads 11 of the battery cells to pass through the slits in the front-rear direction; and rib structures for supporting the bus bars 30 around the slits.

[0050] The front frame 22 and the rear frame 23 may be provided to be hinged to both ends of the top frame 21. In this case, when the electrode leads 11 of the battery cells are fitted into the slits, since the front frame 22 or the rear frame 23 can be rotated from the outside to the inside, the electrode leads 11 can be more easily fitted into the corresponding slits.

[0051] Meanwhile, the plurality of bus bars 30 according to the present disclosure may be fixedly coupled to the front frame 22 and the rear frame 23. The battery cells may be connected in series and in parallel by welding the electrode leads 11 to the bus bars 30 in a predetermined pattern. For example, the positive electrode leads of two or more battery cells are stacked, set to pass through the slits to be pulled out in front of the front frame 22, and then welded to one side of the bus bar 30. In addition, the negative electrode leads of two or more adjacent battery cells are overlapped, set to pass through another slit to be pulled out in front of the front frame 22, and then welded to the other side of the bus bar 30 to which the positive electrode leads are attached. For the bus bar 30 located in front of the rear frame 23, the electrode leads 11 are also welded in the same manner. If the electrode leads 11 of the battery cells are welded to the bus bars 30 in this pattern, all the battery cells can be connected in series and in parallel.

[0052] The battery module 100 includes: a BMS (not shown, battery management system) for monitoring the states of the battery cells and controlling the charging and discharging of the battery cells; and a voltage sensing member 40 for transmitting the node voltages of the series-connected battery cells and transmitting the voltage information of each battery cell to the BMS. The voltage sensing member 40 and the BMS may be connected using a connector, a harness cable, etc.

[0053] In this embodiment, the voltage sensing member 40 may be made of an FPCB (flexible printed circuit board). The FPCB is easy to form a fine pattern and has excellent flexibility, thereby enabling 3D wiring, so that it is easy to arrange even within the battery module 100 with large space limitations.

[0054] The voltage sensing member 40 includes: a body portion (not shown) extending along the longitudinal direction of the battery stack 10 from the top of the battery stack 10; and a plurality of sensing portions 50 located at both ends of the body portion (not shown) to extend into several branches.

[0055] Since the battery cells are connected in series through each bus bar 30, the voltage measured at each bus bar 30 corresponds to the node voltage of the series-connected battery cells. Accordingly, the plurality of sensing units 50 are connected to the plurality of bus bars 30 in a one-to-one correspondence, and respectively sense the voltage of the corresponding bus bar 30.

[0056] Meanwhile, in the conventional battery module 100, in order to connect each bus bar 30 and each sensing unit 50, a metal terminal is compressed to one end of the sensing unit 50, and the metal terminal and the bus bar 30 are laser welded. However, the welded components are practically impossible to rework or replace, and quality control is difficult because the welding quality varies according to the skills of the workers. Accordingly, the present disclosure is configured such that each bus bar 30 and each sensing unit 50 can be connected in a non-welded type as described below.

[0057] Each of the plurality of bus bars 30 according to the present disclosure has a pinhole 32 that penetrates each bus bar in the thickness direction, and each sensing unit 50 has a joining pin 60 that is configured to be inserted into and released from the pinhole 32.

[0058] Reference Figure 3 and Figure 4 , the joining pin 60 includes a base portion 61 and a hole insertion portion 62, and is made of a conductive metal material.

[0059] The base portion 61 may be provided in a plate shape having a predetermined thickness and may be attached to one surface of the sensing unit 50 to face the surface. In addition, at least one side bar 61a, 61b may be provided on the surface of the base portion 61. In this embodiment, three side bars are provided, and two of these side bars 61a, 61b are symmetrically provided with respect to the hole insertion portion 62, but the scope of the present disclosure is not limited thereto. That is, the number and position of the side bars 61a, 61b may be configured differently from this embodiment.

[0060] As will be described later, when the hole insertion portion 62 is fastened to the pinhole 32 of the bus bar 30, the side bars 61a, 61b of the base portion 61 compress and contact the surface of the bus bar 30. The side bars 61a, 61b can be used to prevent a gap between the bus bar 30 and the joining pin 60 by absorbing tolerances.

[0061] The base portion 61 may be electrically connected to the bonding portion 51, which is provided at the end region of the sensing unit 50, by a reflow soldering process.

[0062] Since each sensing unit 50 of this embodiment is a part of the voltage sensing member 40, similar to the voltage sensing member 40, the sensing unit 50 is configured as a flexible printed circuit board. Each sensing unit 50 includes a conductor pattern (not shown) and an outer film layer for covering the conductor pattern.

[0063] The joint portion 51 of the sensing unit 50 can be regarded as the part where the conductor pattern (not shown) is exposed by partially removing the outer film layer. By placing solder paste on the joint portion 51 and applying heat thereto to melt the solder paste so that the base portion 61 is attached to the joint portion 51, the bonding pin 60 and the sensing unit 50 can be electrically connected.

[0064] The hole insertion portion 62 can extend in a direction orthogonal to the base portion 61 and can be arranged to be inserted into the pin hole 32 of the bus bar 30.

[0065] Specifically, the hole insertion portion 62 of this embodiment includes a first column 62a and a second column 62b, and the first column 62a and the second column 62b are formed to extend parallel to each other. The first column 62a and the second column 62b respectively have end portions E1, E2 formed in a hook shape.

[0066] The hook-shaped end portions E1, E2 can pass through the pin hole 32 of the bus bar 30 and be hooked to the rear surface of the bus bar 30.

[0067] Figure 5 and Figure 6 is a diagram showing the assembly process between the bus bar 30 and the sensing unit 50 according to an embodiment of the present disclosure, and Figure 7 is a cross-sectional view taken along the Figure 6 line I-I’ of.

[0068] Next, the connection method and connection structure of the bus bar 30 and the sensing unit 50 according to an embodiment of the present disclosure will be described with reference to Figures 5 to 7 .

[0069] Each bus bar 30 and each sensing unit 50 can be connected after assembling the bus bar frame assembly 20 and the cell stack 10. When assembling the bus bar frame assembly 20 and the cell stack 10, the voltage sensing member 40 can be placed on the upper portion of the cell stack 10 in a state of being attached to the lower surface of the top frame 21.

[0070] The bus bar 30 is installed at a predetermined position of the front frame 22 and the rear frame 23, and each sensing unit 50 can be positioned corresponding to the upper portion of each bus bar 30.

[0071] In this state, as shown in Figure 5 and Figure 6As shown, the bonding needle 60 portion of the sensing unit 50 is inserted into the pinhole 32 of the bus bar 30. At this time, the hole insertion portion 62 is forcibly pressed into the pinhole 32 so that the first column 62a and the second column 62b that are splayed can be closed. Since the hook-shaped ends E1, E2 are hooked on the rear surface of the bus bar 30, the hole insertion portion 62 inserted in this way will not fall off again in the reverse direction.

[0072] That is, referring to Figure 7 , after the end E1 of the first column 62a and the end E2 of the second column 62b come out to the opposite side of the pinhole 32, the end E1 of the first column 62a and the end E2 of the second column 62b are stretched back to their initial state by elasticity and are thus hooked on the rear surface of the bus bar 30. Therefore, even if the bonding needle 60 is pulled in the reverse direction, the bonding needle 60 does not come out of the pinhole 32 of the bus bar 30 again.

[0073] Preferably, when the bonding needle 60 is fastened to the bus bar 30, the contact portions of the side strips 61a, 61b of the base 61 that contact the bus bar 30 are compressed by the bus bar 30 to about 0.05 mm or less, and the length of the hole insertion portion 62 can be determined such that the side strips 61a, 61b contact the bus bar 30 compared with the thickness of the bus bar 30.

[0074] When performing rework or replacement, a jig (not shown) is used to close the end E1 of the first column 62a and the end E2 of the second column 62b again, and the end E1 of the first column 62a and the end E2 of the second column 62b are pushed in the reverse direction (-X axis direction) so that the bonding needle 60 is withdrawn from the bus bar 30.

[0075] As described above, according to the structure and function of the embodiment of the present disclosure, the bus bar 30 and the sensing unit 50 can be easily and quickly connected by a non-welding method, and compared with connecting by welding, the bus bar has a stronger connection strength. The bus bar 30 and the sensing unit 50 can be connected.

[0076] Through the structure and operation of the embodiment of the present disclosure as described above, the bus bar 30 and the sensing unit 50 can be easily and quickly connected by a non-welding method, and compared with welding, the bus bar 30 and the sensing unit 50 can be connected with a stronger connection strength.

[0077] Moreover, according to the present disclosure, rework can be performed on the connection between the bus bar 30 and the sensing unit 50. In addition, if a problem occurs in the voltage sensing member 40, the voltage sensing member 40 can be replaced only with a new voltage sensing member 40.

[0078] Next, referring to Figure 8Describe another embodiment of the present disclosure. The same reference numerals as those in the previous embodiments denote the same components, and the same components will not be described again, and the features different from the previous embodiments will be mainly described.

[0079] The battery module 100 according to another embodiment of the present disclosure is different from the battery module 100 of the previous embodiment in the shapes of the bus bar 30 and the pin hole 33.

[0080] Refer to Figure 8 , the pin hole 33 includes: a first hole region 33a that is formed to have a diameter gradually decreasing from the front surface of the bus bar 30 to a predetermined depth; and a second hole region 33b that is connected to an end point of the first hole region 33a and has a constant diameter to the rear surface of the bus bar 30.

[0081] The end portions E1, E2 of the hole insertion portion 62 can pass through the first hole region 33a and exit to the rear surface of the bus bar 30 through the second hole region 33b. The diameter of the portion starting from the first hole region 33a can be formed to be the same as or slightly smaller than the width of the end portions E1, E2 of the hole insertion portion 62, and this diameter can gradually decrease as it approaches the second hole region 33b.

[0082] If the pin hole 33 of the bus bar 30 is configured as in this embodiment, then if the end portions E1, E2 of the hole insertion portion 62 are closed with a slight force and placed slightly on the pin hole 33 and then a force is applied in the positive direction (X-axis direction), the hole insertion portion 62 can be easily inserted into the pin hole 33. Therefore, in this embodiment, there is an advantage that each sensing unit 50 and each bus bar 30 can be more easily connected compared to the previous embodiments.

[0083] Meanwhile, the battery pack according to the present disclosure may include at least one battery module of the present disclosure. In addition to the battery module, the battery pack according to the present disclosure may further include a battery pack housing for accommodating the battery module and various devices for controlling the charging and discharging of each battery module, such as a main BMS, a current sensor, a fuse, etc.

[0084] The battery module according to the present disclosure can be applied to vehicles, such as electric vehicles or hybrid electric vehicles. That is, the vehicle may include the battery module according to the present disclosure.

[0085] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, although indicating the preferred embodiments of the present disclosure, are given only by way of illustration, because various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art according to this detailed description.

[0086] At the same time, when terms indicating the upper, lower, left, right, front, and rear directions are used in the specification, it is obvious to those skilled in the art that these terms only represent relative positions for convenience of explanation and can be changed based on the position of the observer or the object to be observed.

Claims

1. A battery module, comprising: a plurality of battery cells, the plurality of battery cells being connected in series or connected in series and in parallel; a plurality of bus bars, the plurality of bus bars being connected to corresponding electrode leads of the battery cells; and a voltage sensing member having sensing portions respectively connected to the bus bars, wherein each of the plurality of bus bars has a pinhole that penetrates each bus bar in a thickness direction, and each of the sensing portions has a mating pin configured to be inserted into and released from the pinhole, wherein the mating pin includes: a base portion attached to one surface of the sensing portion; and a hole insertion portion configured to extend in a direction orthogonal to the base portion and arranged to be inserted into the pinhole, wherein the hole insertion portion includes a first post and a second post, the first post and the second post being formed to extend parallel to each other, wherein each of the first post and the second post has a hooked end, and each of the hooked ends passes through the pinhole and is hooked to a rear surface of the bus bar.

2. The battery module according to claim 1, Among them, wherein the pinhole includes: a first hole region formed to have a diameter that gradually decreases from a front surface of the bus bar to a predetermined depth; and a second hole region connected to an end point of the first hole region and formed to have a constant diameter to the rear surface of the bus bar.

3. The battery module according to claim 1, Among them, wherein the base portion is formed in a plate shape having a predetermined thickness and has at least one side strip formed to protrude from a surface of the base portion.

4. The battery module according to claim 3, Among them, wherein the at least one side strip is provided as a plurality of side strips, and among the plurality of side strips, at least two side strips are symmetrically arranged based on the hole insertion portion.

5. The battery module according to claim 1, Among them, wherein the sensing portion further includes a bonding portion welded and electrically connected to the base portion.

6. The battery module according to claim 1, Among them, wherein the voltage sensing member is formed of a flat flexible cable or a flexible printed circuit board.

7. A battery pack, comprising the battery module according to any one of claims 1 to 6.

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