Battery module and method for welding electrode leads of battery cells included in battery module

Abstract

The present disclosure is a battery module including: a battery cell stack including a plurality of battery cells, each of the plurality of battery cells having an electrode lead; a cover frame having a slit through which the electrode lead passes and configured to cover a front portion or a rear portion of the battery cell stack; and a lead bonding portion provided on an outer side of the cover frame and formed by overlapping the electrode leads of the battery cells such that at least a portion of the overlapped electrode leads are welded, the lead support unit is configured to provide a pressing force from a rear surface of the lead bonding portion toward a front surface of the lead bonding portion such that the overlapped electrode leads are in close contact at the lead bonding portion.

Description

Technical Field

[0001] This disclosure relates to a battery, and more specifically, to a battery module in which electrode leads of battery cells are soldered without busbars, and a method for soldering electrode leads of battery cells.

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2024-0096923, filed with the Korean Intellectual Property Office on July 23, 2024, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] A semi-permanent battery that converts electrical energy into chemical energy and can be repeatedly charged and discharged is called a secondary battery, in order to distinguish it from a primary battery that cannot be reused after a single use.

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

[0005] In particular, lithium-ion batteries have recently been actively used as batteries for electric vehicles due to their advantages such as high energy storage density, lightweight and miniaturized design, excellent safety, low discharge rate, and long lifespan. For reference, lithium-ion batteries are generally classified into cylindrical, prismatic, and pouch types according to their manufacturing form, and their applications range from electric vehicle batteries to ESS batteries and other electrical devices.

[0006] Currently, a single lithium-ion battery cell cannot generate enough power to power an electric vehicle. To use secondary batteries as an energy source for electric vehicles, battery modules must be formed by connecting multiple lithium-ion battery cells in series and / or parallel. Typically, a battery pack is configured to include a Battery Management System (BMS) that connects the battery modules in series and maintains their function, a cooling system, a Battery Disconnection Unit (BDU), electrical wiring cables, etc.

[0007] On the other hand, such as Figure 1 As shown, when a battery module with a pouch-type secondary battery is configured, the electrode leads 1a and 1b of the pouch-type secondary battery are laser-welded to the busbar 3. Here, the busbar 3 refers to an electrical conductor made of a metallic material such as copper and typically manufactured in a strip or square shape.

[0008] A pouch-type secondary battery is stacked vertically in one direction, forming a battery cell stack, and a busbar frame 2 can be arranged on the front and / or rear side of the battery cell stack. The busbar frame 2 is made of electrically insulating material, has slits through which electrode leads 1a and 1b can pass, and is configured such that multiple busbars 3 can be mounted on the outer surface. That is, the busbars 3 can be mounted on the outer surface of the busbar frame 2, and multiple electrode leads 1a and 1b are welded to each busbar, allowing the secondary batteries to be connected in series and / or in parallel.

[0009] In addition, the voltage information of the secondary battery in the battery module is transmitted to the BMS through the sensing component 4 connected to each busbar 3, and the BMS monitors the status of each secondary battery based on the voltage information and controls the charging and discharging of the secondary battery.

[0010] A wire harness, flat flexible cable (FFC), or flexible printed circuit board (FPCB) is used as the sensing component 4. Typically, one side of the sensing board 5 is pressed to the end of the sensing component 4, and the other side of the sensing board 5 is soldered to the busbar 3. However, the battery module manufacturing method of connecting the electrode leads 1a, 1b to the sensing board 5 via the busbar 3 has the disadvantage of increased manufacturing cost and weight. Summary of the Invention

[0011] Technical issues

[0012] This disclosure is designed to address the problems of the prior art, and therefore aims to provide a battery module in which individual battery cells are electrically connected by soldering electrode leads of the battery cells without the use of busbars.

[0013] In addition, this disclosure aims to provide an electrode lead welding method that can weld electrode leads in close contact without a busbar.

[0014] The technical problems that this disclosure seeks to solve are not limited to those described above, and those skilled in the art will clearly understand from the description of the invention below that other problems not mentioned above will also be apparent.

[0015] Technical solution

[0016] In one aspect of this disclosure, a battery module is provided, the battery module comprising: a battery cell stack including a plurality of battery cells, each of the plurality of battery cells having an electrode lead; a cover frame having a slit through which the electrode lead passes, and the cover frame being configured to cover a front or rear portion of the battery cell stack; and a lead joint disposed outside the cover frame and formed by overlapping with the electrode lead of the battery cell, such that at least a portion of the overlapping electrode lead is welded, wherein the cover frame includes a lead support unit configured to provide a pressing force from a rear surface of the lead joint toward its front surface, such that the overlapping electrode leads are in close contact at the lead joint.

[0017] The lead support unit may include an elastic member that is attached to the plate surface of the cover frame and elastically presses against the lead joint.

[0018] The elastic member may include: a support block that contacts the rear surface of the lead wire joint; and a spring, one end of which is connected to the plate surface of the cover frame and the other end of which is connected to the support block.

[0019] The support block may include: a spring connection portion connected to a spring; a first lead wire support portion extending from one side of the spring connection portion toward the lead wire engagement portion; and a second lead wire support portion spaced apart from the first lead wire support portion and extending from the other side of the spring connection portion toward the lead wire engagement portion.

[0020] The spring connection can be configured to be spaced apart from the lead wire connection by a predetermined interval.

[0021] The cover frame may include a first guide plate and a second guide plate, which are spaced apart from each other and arranged side by side and protrude from the plate surface of the cover frame, and an elastic member may be arranged in the space between the first guide plate and the second guide plate.

[0022] The elastic member may include: a support block that contacts the rear surface of the lead wire junction; and a spring, one end of which is connected to the plate surface of the cover frame and the other end of which is connected to the support block, and the support block may have a width corresponding to the gap between the first guide plate and the second guide plate.

[0023] The cover frame may have a slit on at least one side of the lead support unit, either on the left or right side.

[0024] In another aspect of this disclosure, an electrode lead welding method for joining electrode leads between battery cells is also provided. This electrode lead welding method includes the following steps: preparing a cover frame including a slit through which the electrode leads pass and an elastic member configured to elastically press the electrode leads; inserting two or more electrode leads into the slit and leading the electrode leads from the rear side of the cover frame to the front side of the cover frame; compressing the elastic member; bending the two or more electrode leads that have passed through the slit to overlap each other to form a lead joint, and placing the lead joint in front of the pressed elastic member; releasing the compression of the elastic member so that the rear surface of the lead joint is pressed, and pressing the front surface of the lead joint using a welding fixture; and performing welding on the lead joint through a through-hole provided in the welding fixture.

[0025] The elastic member may include: a support block that contacts the rear surface of the lead wire junction; and a spring, one end of which is connected to the plate surface of the cover frame and the other end of which is connected to the support block.

[0026] The support block can be formed to protrude from the rear surface of the lead wire joint to have a pocket space on the inside, and a spring pressing fixture can be inserted into the pocket space and used to push the support block to compress the spring toward the plate surface of the cover frame.

[0027] The cover frame may include a first protrusion and a second protrusion configured to project from the plate surface of the cover frame and spaced apart from each other, and an elastic member may be arranged in the space between the first protrusion and the second protrusion.

[0028] The elastic member may include: a support block that contacts the rear surface of the lead wire joint; and a spring, one end of which is connected to the plate surface of the cover frame and the other end of which is connected to the support block, and the support block may have a width corresponding to the gap between the first protrusion and the second protrusion.

[0029] The slit can be positioned on at least one of the left and right sides of the elastic member, with the elastic member as the reference.

[0030] In another aspect of this disclosure, a battery pack including the above-described battery module is also provided.

[0031] Beneficial effects

[0032] According to this disclosure, a battery module can be provided in which battery cells are electrically connected by electrode leads of the battery cells without using busbars to weld the battery cells together.

[0033] Alternatively, a method for welding electrode leads can be provided that allows welding electrode leads in a tight contact state without the need for a busbar.

[0034] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from this specification and the accompanying drawings effects not mentioned herein. Attached Figure Description

[0035] Figure 1 This is a diagram showing a portion of a battery module according to the prior art, and depicts a busbar and electrode leads soldered to the busbar.

[0036] Figure 2 This is a cross-sectional view showing a portion of a battery module according to the prior art.

[0037] Figure 3 This is a front perspective view showing the main components of a battery module according to an embodiment of the present disclosure.

[0038] Figure 4 This is a diagram illustrating the connection structure between the cover frame and the electrode leads in a battery module according to an embodiment of the present disclosure.

[0039] Figure 5 This is a diagram illustrating a coverage framework according to an embodiment of the present disclosure.

[0040] Figure 6 This is a diagram showing the main components of the lead support unit of the cover frame according to an embodiment of the present disclosure.

[0041] Figures 7 to 9 This is a process diagram illustrating the electrode lead welding process according to embodiments of the present disclosure.

[0042] Figure 10 Is with Figure 9 The corresponding perspective view shows the lead wire joint being pressurized by a welding fixture and an elastic member.

[0043] Figure 11 and Figure 12 Is with Figure 8 and Figure 9 The corresponding diagram shows the welding process for the six electrode leads. Detailed Implementation

[0044] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general or dictionary meaning, but rather as interpreted based on its meaning and concept corresponding to the technical aspects of the present disclosure, based on the principle that inventors are allowed to appropriately define terms for best interpretation. Therefore, the description presented herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of the present disclosure; thus, it should be understood that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0045] Because the embodiments of this disclosure are provided to explain the disclosure more fully to those skilled in the art, the shapes and dimensions of the components in the drawings may be shown enlarged, omitted, or schematically for clarity. Therefore, the dimensions and proportions of each component do not perfectly reflect the actual dimensions or proportions.

[0046] Figure 3 This is a front perspective view showing the main components of a battery module according to an embodiment of the present disclosure. Figure 4 This is a diagram illustrating the connection structure between the cover frame and the electrode leads in a battery module according to an embodiment of the present disclosure, and Figure 5 This is a diagram illustrating a coverage framework according to an embodiment of the present disclosure.

[0047] Reference Figures 3 to 5 According to embodiments of the present disclosure, a battery module includes a battery cell stack 100, a cover frame 200, and a voltage sensing unit 300.

[0048] The battery cell stack 100 is an assembly of the battery cell 110. The battery cells 110 are erected in the vertical direction (±Z) and stacked in the horizontal direction (±X) to form the battery cell stack 100.

[0049] A buffer pad or cooling sheet can be added between the battery cells 110. The buffer pad or cooling sheet can be used to absorb shocks or effectively release heat from each battery cell 110 to the outside. A pouch-type battery cell 110 can be used as the battery cell 110.

[0050] Although not specifically shown, the pouch cell 110 may include electrode assemblies, an electrolyte, and a pouch exterior for sealing and storing them. The electrode assemblies have a stacked structure in which positive / separator / negative / separator plates are repeatedly stacked, and the positive and negative plates are provided with electrode tabs, at least one of which is connected to an electrode lead 111. The electrode leads 111 extend from the inside to the outside of the pouch housing and serve as electrode terminals of the cell 110. Here, the electrode leads 111 are collectively referred to as positive lead 111a and negative lead 111b. The pouch exterior may be made of a metal film (e.g., an aluminum film) to protect internal components such as the electrode assemblies and electrolyte, and to improve the electrochemical and heat dissipation properties of the electrode assemblies and electrolyte. The aluminum film may be interposed between an insulating layer made of insulating material and an internal adhesive layer to ensure electrical insulation.

[0051] In the battery module according to this disclosure, the electrode leads 111 of adjacent battery cells 110 can overlap each other in a predetermined pattern, so that the battery cells 110 can be connected in series or in parallel.

[0052] For example, in a stack of battery cells 100, suppose a battery cell 110 is the Nth battery cell 110, and the other battery cells are the (N+1)th battery cells in sequence. The N+2th ...Battery cells 110, and at this time, adjacent battery cells 110 are arranged such that the positive electrode lead 111a and the negative electrode lead 111b face opposite directions. On the front surface of the battery cell stack 100, the positive electrode lead 111a of the Nth battery cell 110 and the negative electrode lead 111b of the (N+1)th battery cell overlap. Furthermore, on the rear surface of the battery cell stack 100, the positive electrode lead 111a of the (N+1)th battery cell 110 and the negative electrode lead 111b of the (N+2)th battery cell 110 overlap. By overlapping the electrode leads 111 of the battery cells 110 in this manner and joining the electrode leads 111 using the electrode lead welding method described later, the battery cells 110 can be connected in series.

[0053] As another example, two or three consecutive battery cells 110 are grouped together, with identical groups arranged such that their polarities face the same direction, and other groups arranged such that their polarities face opposite directions. Furthermore, if the electrode leads 111 are joined in a manner where one group of positive leads 111a and another group of negative leads 111b overlap and are then welded together, the battery cells 110 can be connected in series and in parallel.

[0054] Specifically, the battery module according to embodiments of this disclosure is configured to use the electrode lead welding method described later in the presence of a busbar that is a metal conductor according to the prior art (see reference). Figure 1 and Figure 2 In the case of welding electrode lead 111 to connect to battery cell 110.

[0055] In other words, unlike existing technologies, the battery module according to embodiments of this disclosure has a first welding portion W1 in which the electrode leads 111 of the battery cells 110 to be connected overlap and are directly welded to join the overlapping electrode leads 111 to each other, instead of welding the electrode leads 111 to a busbar. In other words, one or more first welding portions may exist. In other words, the battery module includes a lead joint portion 120, which is formed by overlapping the electrode leads 111 of the battery cells 110 in a predetermined pattern, such that at least a portion of the overlapping electrode leads 111 is welded. The welding method performed in this case can be, for example, any one of laser welding, ultrasonic welding, and resistance welding.

[0056] According to embodiments of the present disclosure, the cover frame 200 can be arranged on the front and rear surfaces of the battery cell stack 100 as a unit for supporting the battery cell stack 100.

[0057] The cover frame 200 has slits 220 formed at predetermined intervals along the stacking direction (±X) of the battery cells 110. Electrode leads 111 of the battery cells 110 can be led out from the cover frame 200 via the slits 220. A portion of the electrode leads 111 that have passed through the slits 220 can be bent to face the plate surface of the cover frame 200. At this time, two or more electrode leads 111 to be electrically connected at least partially overlap on the outer side of the cover frame 200 to form a lead joint 120. The electrode leads 111 forming the lead joint 120 can be configured to be joined without separating from each other by an electrode lead welding method described later.

[0058] The cover frame 200 may include a plurality of lead support units 210, which are arranged at predetermined intervals along the stacking direction (±X) of the battery cells 110, such as... Figure 5 As shown. The lead support unit 210 is a component that supports the lead joint 120 during the soldering process.

[0059] The lead support unit 210 can be configured to provide a pressing force from the rear surface of the lead joint 120 toward the front surface, such that no gaps are created between the electrode leads 111 of the lead joint 120. For example, the lead support unit 210 may include an elastic member that is coupled to the plate surface of the cover frame 200 and elastically presses the lead joint 120.

[0060] The elastic component may include a support block 211 and a spring 212, such as Figure 6 As shown.

[0061] The support block 211 can be configured to contact the rear surface of the lead junction 120. For example, the support block 211 can be configured to have a length corresponding to the width of the electrode lead 111 in order to stably support the lead junction 120.

[0062] Additionally, the support block 211 may include: a spring connection portion 211a connected to the spring 212; a first lead wire support portion 211b extending from one side of the spring connection portion 211a toward the lead wire joint portion 120; and a second lead wire support portion 211c spaced apart from the first lead wire support portion 211b and extending from the other side of the spring connection portion 211a toward the lead wire joint portion 120.

[0063] The first lead support portion 211b and the second lead support portion 211c can be configured to have surfaces facing the lead joint portion 120 and contacting the lead joint portion 120, respectively. The first lead support portion 211b and the second lead support portion 211c can be configured to press the lead joint portion 120 while supporting the rear surface of the lead joint portion 120 by the elastic force of the spring 212. Additionally, the spring connecting portion 211a can be configured to be spaced apart from the lead joint portion 120 by a predetermined distance.

[0064] In this embodiment, the support block 211 is manufactured in an approximately "U" shape, and a storage space S is formed between the support block 211 and the lead wire connection portion 120. As will be described later, by providing the storage space S, the support block 211 can be prevented from joining with the electrode lead wire 111.

[0065] Spring 212 can be a helical spring 212 as a unit for providing pressing force to lead wire joint 120. Spring 212 can be a leaf spring instead of helical spring 212. Spring 212 can be configured with one end connected to a plate of cover frame 200 and the other end connected to support block 211. Multiple springs 212 can be arranged along the longitudinal direction (Z direction) of support block 211.

[0066] Refer again Figure 5 and Figure 6 The cover frame 200 includes a first guide plate 230 and a second guide plate 240, which are spaced apart from each other and arranged side by side, protruding from the plate surface of the cover frame 200. The aforementioned elastic member can be arranged in the space between the first guide plate 230 and the second guide plate 240.

[0067] The first guide plate 230 and the second guide plate 240 can guide the movement of the elastic member, such that the elastic member is blocked by the first guide plate 230 and the second guide plate 240 when compressed or stretched, and moves left and right without deformation. The first guide plate 230 and the second guide plate 240 can be configured such that the spacing between them corresponds to the width of the support block 211.

[0068] The first guide plate 230 and the second guide plate 240 are configured to protrude at least further than the support block 211 when the spring 212 is fully compressed. Additionally, the first guide plate 230 and the second guide plate 240 are configured to have the same protruding length relative to the plate surface of the cover frame 200.

[0069] The first guide plate 230 and the second guide plate 240 can be used together with the first lead support portion 211b and the second lead support portion 211c of the support block 211 to support one side and the other side of the lead joint portion 120.

[0070] In the cover frame 200, slits 220 may be provided on at least one of the left and right sides of the lead support unit 210 (i.e., the elastic member). For example, in this embodiment, slits 220 may be provided on the left side of a first guide plate 230 that protects and guides the elastic member, or on the right side of a second guide plate 240 that protects and guides the elastic member. Electrode leads 111 pass through adjacent slits 220 and bend toward the first guide plate 230 or the second guide plate 240, respectively, to form a lead junction 120 in front of the elastic member.

[0071] On the other hand, the voltage sensing unit 300 refers to a component that senses the node voltage of the electrically connected battery cells 110 and transmits the voltage information of each battery cell 110 to the battery management system (not shown, BMS: Battery Management System). The BMS can monitor the state of the battery cells 110 through the voltage sensing unit 300 and control the charging and discharging of the battery cells 110.

[0072] The voltage sensing unit 300 may include a signal transmission component 310 and a sensing plate 320 (see Figure 3 The voltage sensing unit 300 can be implemented as a thin-film cable, such as a flexible printed circuit board (FPCB) or a flat flexible cable (FFC).

[0073] FPCBs can be manufactured by placing copper-clad laminates on a base film and stacking dry films to form conductors at regular intervals through exposure, development, and etching processes, followed by bonding a cover film. Alternatively, FFCs can be manufactured by arranging conductors at regular intervals on a base film and stacking a cover layer on top of it.

[0074] The voltage sensing unit 300 in the form of a thin-film cable has excellent conductivity of wires, and the insulation between the wires is perfectly ensured by a single insulating film, so a large number of signals can be processed with minimal volume.

[0075] In this embodiment, the signal transmission member 310 of the voltage sensing unit 300 can be configured to extend from the upper part of the battery cell stack 100 in the longitudinal direction (±Y direction) of the battery cell stack 100. Furthermore, a sensing plate 320 connected to the lead overlap portion can be provided at both ends of the voltage sensing unit 300. Additionally, a connector can be provided at one end of the voltage sensing unit 300. The connector can be connected to the BMS via a cable connector (not shown).

[0076] Each sensing plate 320 can be connected to a predetermined lead junction 120 in a one-to-one relationship (see...). Figure 4 At this time, the sensing plate 320 can be directly soldered to the lead joint 120. That is, the battery module according to this embodiment has a first solder joint W1 in which the positive electrode lead 111a and the negative electrode lead 111b are soldered, and a second solder joint W2 in which the sensing plate 320 and the lead joint 120 are soldered. In other words, the battery module according to the embodiment of this disclosure has a structure in which there is no busbar, and soldering is performed between the electrode leads 111 and between the electrode leads 111 and the sensing plate 320.

[0077] In the following text, refer to Figures 7 to 10 The electrode lead welding method according to this disclosure will be described.

[0078] The electrode lead welding method according to this disclosure can be used to manufacture a battery module in which the electrode leads 111 are welded without a busbar, as described above.

[0079] The electrode lead welding method may include the following steps: preparing a cover frame 200 having a slit 220 through which electrode leads 111 can pass and an elastic member capable of elastically pressing the electrode leads 111; inserting two or more electrode leads 111 into the slit 220 and leading the electrode leads 111 from the rear of the cover frame 220 to the front of the cover frame 220; pressing the elastic member; bending and overlapping the two or more electrode leads 111 that have passed through the slit 220 to form a lead joint 120, and placing the lead joint 120 in front of the compressed elastic member; releasing the compression of the elastic member so that the rear surface of the lead joint 120 is pressed, and pressing the front surface of the lead joint 120 using a welding fixture 20; and performing welding on the lead joint 120 through a through hole 21 provided in the welding fixture 20.

[0080] More specifically, when two battery cells 110 are to be connected in series, for example, the electrode leads 111 are welded using the electrode lead welding method according to this embodiment.

[0081] First, prepare the aforementioned cover frame 200, and lead the positive electrode lead 111a of one battery cell 110 and the negative electrode lead 111b of another battery cell 110 from the rear side to the front side of the cover frame 200 through the corresponding slits 220.

[0082] Then, as Figure 8 As shown, spring 212 is pressed to push support block 211 into the space between first guide plate 230 and second guide plate 240. At this time, spring pressing fixture 30 can be used. Spring pressing fixture 30 is in the form of a rod and can be inserted into the storage space S of support block 211. Spring pressing fixture 30 moves toward the plate surface of the covering frame 200 to press spring 212. Here, storage space S refers to the empty space surrounded by the first lead wire support 211b, second lead wire support 211c, and spring connecting part 211a as described above.

[0083] Additionally, the positive lead 111a and the negative lead 111b are bent to overlap each other to form a lead joint 120. At this time, the rear surface of the lead joint 120 is made to face and contact the ends of the first guide plate and the second guide plate.

[0084] Then, as Figure 9As shown, the welding fixture 20 is brought into close contact with the front surface of the lead joint 120, and the spring-pressing fixture 30 is separated from the support block 211 to release the compression of the spring 212. Then, the rear surface of the lead joint 120 is pressed by the first lead support portion 211b and the second lead support portion 211c of the support block 211, and the front surface of the lead joint 120 can be pressed by the welding fixture 20. In this case, the positive lead 111a and the negative lead 111b are brought into close contact with each other, and no gap occurs between them. In this way, when the positive lead 111a and the negative lead 111b are in close contact, a laser is irradiated onto the lead joint 120 using, for example, a laser welding machine 40, to perform laser welding on the positive lead 111a and the negative lead 111b. At this time, the laser irradiates the center of the lead joint 120. Since the storage space S of the support block 211 is located behind the center of the lead junction 120, even if the positive lead 111a and the negative lead 111b melt, the heat will not be directly transferred to the support block 211. This prevents the support block 211 and the electrode lead 111 from being integrally joined.

[0085] Welding fixture 20 can be configured as follows Figure 10 The fixture is generally box-shaped and may have through holes 21 formed through the welding fixture 20. Multiple through holes 21 may be provided. Multiple through holes 21 may be separated by barriers. The through holes 21 can serve as channels for introducing welding units such as laser beams, ultrasonic horns, welding electrodes, etc., and prevent spatter and other debris generated during welding. The welding fixture 20 may include a lower surface that can face and contact the wire joint 120. Additionally, the welding fixture 20 may be configured to correspond to the dimensions of the wire joint 120 in order to apply pressure to the entire wire joint 120.

[0086] Figure 11 and Figure 12 It corresponds to Figure 8 and Figure 9 The figure shows the welding process of the six electrode leads 111.

[0087] The electrode leads 111 of three or more battery cells 110 can be electrically connected by welding according to the electrode lead welding method of this disclosure.

[0088] For example, such as Figure 11 As shown, the positive leads 111a of three battery cells 110 are led out to the front of the cover frame 200 through the same slit 220 and overlap each other. In addition, the negative leads 111b of the other three battery cells 110 are led out to the front of the cover frame 200 through another slit 220 and overlap each other.

[0089] Subsequently, as described above, a lead junction 120 is formed by pushing three positive electrode leads 111a and three negative electrode leads 111b into the space between the first guide plate 230 and the second guide plate 240, and the three positive electrode leads 111a and three negative electrode leads 111b are bent to overlap each other.

[0090] Next, the rear surface of the lead joint 120 is pressed using an elastic member, and the front surface of the lead joint 120 is pressed using a welding fixture 20 to perform laser welding while the six electrode leads 111 are in close contact. Then, the six battery cells 110 form a parallel-to-series connection structure (3P2S).

[0091] On the other hand, the battery pack according to this disclosure may include one or more battery modules according to this disclosure. In addition to the battery modules, the battery pack according to this disclosure may also include a battery pack housing for housing the battery modules, and various means for controlling the charging and discharging of each battery module, such as a main BMS, a current sensor, and a fuse.

[0092] The battery module according to this disclosure can be applied to vehicles such as electric vehicles or hybrid electric vehicles. That is, a vehicle may include the battery module according to this disclosure.

[0093] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various changes and modifications within the scope of this disclosure will become apparent to those skilled in the art based on this detailed description.

[0094] Although directional terms such as up, down, left, right, front, and back are used in this specification, it will be apparent to those skilled in the art that these terms are used for ease of interpretation only to indicate relative positions and may vary depending on the position of the target object or the observer's position.

Claims

1. A battery module, comprising: A battery cell stack, the battery cell stack comprising a plurality of battery cells, each of the plurality of battery cells having electrode leads; A cover frame having slits through which the electrode leads pass and configured to cover the front or rear of the battery cell stack; as well as A lead wire bonding portion is disposed on the outside of the cover frame and is formed by overlapping multiple electrode leads of the plurality of battery cells, such that at least a portion of the overlapping electrode leads is welded. The cover frame includes a lead support unit configured to provide a pressing force from the rear surface of the lead joint toward the front surface of the lead joint, such that the overlapping electrode leads are in close contact at the lead joint.

2. The battery module according to claim 1, wherein, The lead support unit includes an elastic member that is attached to the plate surface of the cover frame and elastically presses against the lead joint.

3. The battery module according to claim 2, wherein, The elastic member includes: Support block, the support block contacting the rear surface of the lead wire junction; and A spring, one end of which is connected to the plate surface of the cover frame, and the other end of which is connected to the support block.

4. The battery module according to claim 3, wherein, The support block includes: A spring connecting part, which is connected to the spring; A first lead support portion extends from one side of the spring connection portion toward the lead engagement portion; and The second lead support portion is spaced apart from the first lead support portion and extends from the other side of the spring connection portion toward the lead joint portion.

5. The battery module according to claim 4, wherein, The spring connection portion is configured to be spaced apart from the lead wire connection portion by a predetermined interval.

6. The battery module according to claim 2, wherein, The cover frame includes a first guide plate and a second guide plate, which are spaced apart from each other and arranged side by side, protruding from the plate surface of the cover frame. The elastic member is arranged in the space between the first guide plate and the second guide plate.

7. The battery module according to claim 6, wherein, The elastic component includes: a support block that contacts the rear surface of the lead wire junction; and a spring, one end of which is connected to the plate surface of the cover frame, and the other end of which is connected to the support block. The support block has a width corresponding to the gap between the first guide plate and the second guide plate.

8. The battery module according to claim 1, wherein, The cover frame has the slit at at least one of the left and right sides of the lead support unit.

9. An electrode lead welding method for joining electrode leads between battery cells, comprising the following steps: Prepare a cover frame, the cover frame including a slit through which the electrode leads pass and an elastic member configured to resiliently press the electrode leads; Two or more of the electrode leads are inserted into the slit, and the electrode leads are led out from the rear side of the cover frame to the front side of the cover frame; Compress the elastic member; Two or more electrode leads that have passed through the slit are bent to overlap each other to form a lead joint, and the lead joint is placed in front of the compressed elastic member; Release the compression of the elastic member, pressing the rear surface of the lead joint, and press the front surface of the lead joint using a welding fixture; and Welding is performed on the lead wire joint through a through hole provided in the welding fixture.

10. The electrode lead welding method according to claim 9, wherein, The elastic member includes: a support block that contacts the rear surface of the lead wire joint; and a spring, one end of which is connected to the plate surface of the cover frame, and the other end of which is connected to the support block.

11. The electrode lead welding method according to claim 10, wherein, The support block is formed to protrude from the rear surface of the lead wire joint to have a storage space on the inside, and The spring pressing fixture is inserted into the storage space, and the spring pressing fixture is used to push the support block to compress the spring toward the plate surface of the cover frame.

12. The electrode lead welding method according to claim 9, wherein, The cover frame includes a first protrusion and a second protrusion configured to project from the plate surface of the cover frame and spaced apart from each other, and The elastic member is arranged in the space between the first protrusion and the second protrusion.

13. The electrode lead welding method according to claim 12, wherein, The elastic component includes: a support block that contacts the rear surface of the lead wire junction; and a spring, one end of which is connected to the plate surface of the cover frame, and the other end of which is connected to the support block. The support block has a width corresponding to the gap between the first protrusion and the second protrusion.

14. The electrode lead welding method according to claim 9, wherein, The slit is disposed at least at one location on the left and right sides of the elastic member, with reference to the elastic member.

15. A battery pack comprising the battery module according to any one of claims 1 to 8.

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