Secondary battery module

Abstract

A secondary battery module of the present invention includes: a battery cell stack in which a plurality of battery cells each having electrode leads protruding therefrom and a plurality of protective pads are stacked, wherein each of the protective pads is inserted so as to be placed between neighboring battery cells; a housing frame having accommodated therein the battery cell stack so as to cover the surfaces of the battery cell stack except for the surface from which the electrode leads protrude; and a bus bar assembly which is coupled to the housing frame to cover a direction in which the electrode leads protrude from the battery cells, and which has a bus bar to which the electrode leads are electrically connected and which has formed therein insertion recesses into which the ends of the protective pads are inserted and fixed, wherein the protective pads include: a pad part made of material having fire resistance or flame retardancy and elasticity; and a rigid body part having a plate shape and made of material having greater rigidity than the pad part.

Description

secondary battery module

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0190449, filed December 22, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a secondary battery module, and more particularly, to a secondary battery module capable of reducing the risk of explosion by preventing flames from spreading to neighboring battery cells even if ignition occurs in at least one of the battery cells included in a battery cell stack.

[0003]

[0004] Demand for high-efficiency secondary batteries is rapidly increasing in industries such as mobile devices and electric vehicles. Among these secondary batteries, lithium secondary batteries, with their high energy density, ability to sustain relatively high voltages, and low self-discharge rates, are commercialized and widely used, and active research and development is underway to improve their performance.

[0005] Secondary batteries have a structure in which an electrode assembly and electrolyte are embedded in a case such as a can or pouch.

[0006] Among these, the pouch-type secondary battery has a structure in which an electrode assembly is mounted within a pouch. At this time, the electrode assembly has a structure in which a positive electrode, a separator, and a negative electrode are repeatedly laminated, and the positive electrode tabs extending from each positive electrode are gathered into one and connected to a positive electrode lead (an electrode lead having a positive pole), and the negative electrode tabs extending from each negative electrode are gathered into one and connected to a negative electrode lead (an electrode lead having a negative pole). In addition, the ends of the positive electrode lead and the negative electrode lead protrude from the pouch so as to be electrically connected to the outside.

[0007] Meanwhile, secondary batteries installed in vehicles, ESS (Energy Storage Systems), etc. are combined in multiples to form secondary battery modules to increase output and electrical storage capacity, and multiple secondary battery modules are combined to form secondary battery packs. In other words, multiple secondary batteries are assembled into a secondary battery module, and multiple secondary battery modules are assembled into a secondary battery pack, which is then installed in vehicles, ESS, etc.

[0008] When the above pouch-type secondary battery is manufactured as a secondary battery module, the secondary batteries (battery cells) are stacked so that their flat surfaces are in contact with each other, and are provided as a battery cell stack (1) in a state of being bound together using tape or a cable, etc., or by applying an adhesive to the contacting surfaces.

[0009] For reference, in the above battery cell stack (1), a protective pad (1b) is additionally provided between adjacent battery cells (1a) to absorb shrinkage and expansion of the battery cells and reduce heat generation.

[0010] Referring to Fig. 1a, which sequentially depicts the appearances of assembling a secondary battery module according to a conventional method, that is, the appearance of a battery cell stack (1), the appearance of the battery cell stack (1) being housed in a housing frame (5) and a busbar assembly (or busbar frame) (3) being coupled from the inside and outside, the appearance of an insulating cover (4) being coupled from the outside of the busbar assembly (3), and the appearance of an end plate (5) being coupled from the outside of the insulating cover (4), the battery cell stack (1) is housed in a housing frame (5) including a top frame (5a) covering the upper surface and a side frame (5b) covering the side surface so as to be protected from external impact, and when the busbar assembly (3) is covered from the inside and outside, it is connected to the busbar mounted on the busbar assembly (3) to form an electrical connection with the outside. And, in order to protect the busbar through which current flows, an insulating cover (4) and an end plate (2) are sequentially connected to the outside of the busbar assembly (3).

[0011] And, in the battery cell stack (1), a predetermined number of battery cells (1a) are stacked so that the electrode leads protrude in the same direction (either to both sides or to one side), and a protective pad (1b) is inserted between the battery cells (1a) to absorb the volume change due to shrinkage and expansion of the battery cells (1a).

[0012] That is, the battery cell stack (1) experiences temperature changes, mechanical loads, shocks, and vibrations depending on the environment in which it is mounted. The protective pad (1b) is provided to protect the battery cell (1a) from such external factors, and one, two, or more battery cells (1a) are stacked between adjacent protective pads (1b).

[0013] A slit is punched in the above busbar assembly (3), and the electrode lead of each battery cell (1a) passes through the slit and is connected to the busbar of the busbar assembly (3) by welding or the like. In addition, each busbar is electrically connected to a terminal that can be electrically connected to an external device.

[0014] Meanwhile, referring to Fig. 1b, which shows a cross-sectional view of a case where a fire occurs at a point where a battery cell stack (1) and a busbar assembly (3) are in contact in an assembled state as in Fig. 1a, in a conventional structure, when a fire occurs in a specific battery cell (1a), the end of the protection pad (1b) that was fixed between the protrusions of the busbar assembly (3) (or fixed by a separate structure or groove) could come off the protrusions due to pressure. In addition, there was a possibility that a flame could spread through the space created by the deformation of the protection pad (1b).

[0015] In addition, not only the flames, but also the dust generated during a fire could move to neighboring battery cells, potentially causing an electrical short and, consequently, a thermal runaway. The dust mentioned here refers to small ash particles that are scattered when compounds within a battery cell (1a) react and / or explode when a fire occurs in that battery cell.

[0016] That is, even if a fire occurs in the battery cell assembly (1), there was a need to suppress or block the spread of flames and dust.

[0017] In particular, secondary battery modules installed in vehicles and other transportation systems face increasing safety risks as their capacity and output increase. Even if a fire were to occur in a secondary battery module, it was necessary to delay thermal runaway as much as possible to ensure passengers had enough time to escape.

[0018]

[0019] Accordingly, the main purpose of the present invention is to provide a secondary battery module that can minimize the gap between a battery cell stack and a busbar assembly to suppress or delay as much as possible the progression to thermal runaway even if ignition occurs in a battery cell, and can prevent the problem of a protection pad coming off from the busbar assembly.

[0020]

[0021] In order to achieve the above-described object, the present invention provides a secondary battery module, comprising: a battery cell stack in which a plurality of battery cells having protruding electrode leads and a plurality of protective pads are stacked, each protective pad being inserted so as to be placed between adjacent battery cells; a housing frame in which the battery cell stack is accommodated so as to cover surfaces of the battery cell stack except for surfaces in which the electrode leads protrude; and a bus bar assembly coupled to the housing frame so as to cover a direction in which the electrode leads protrude from the battery cells, the bus bar assembly having a bus bar to which the electrode leads are electrically connected, and having an insertion groove formed into which ends of the protective pads are inserted and fixed; wherein the protective pad includes a pad portion made of a material having fire resistance or flame retardancy and elasticity, and a rigid portion made of a material having a plate shape and having greater rigidity than the pad portion.

[0022] The above pad portion is laminated in two pieces so as to cover one side and the other side of the rigid body portion with the rigid body portion in between.

[0023] The protective pad is fitted into the fitting groove so that the pad portion covers one side and the entire other side of the rigid body portion.

[0024] The above fitting groove is formed with a slope so that the size gradually increases from one side where the end of the protective pad enters to the other side, so that the protective pad is allowed to move and elastically deform according to the shape of the fitting groove when fitted into the fitting groove.

[0025] The above busbar assembly has a groove formed on the inside facing the battery cell stack, a busbar is joined on the outside, and a chamber portion, which is an empty space, is provided between the busbar and the groove.

[0026] The above busbar assembly includes a plurality of bucket parts having an inwardly convex surface, and the plurality of bucket parts are arranged in parallel along the longitudinal direction of the busbar assembly, and a chamber part forming a space is provided within each bucket part.

[0027] A bus bar is attached to the outer side of the bucket parts selected from the above bucket parts.

[0028] A slit is formed between adjacent buckets, penetrating the inner and outer surfaces of the busbar assembly, and the electrode leads protruding from each battery cell are connected to the busbar through the slit.

[0029] The above bucket parts have a fitting groove formed on the convex surface on the inside.

[0030] Within the above bucket section, ribs are formed to protrude from the surface to reinforce rigidity or to partition the chamber section.

[0031] The battery cell stack is provided in a shape in which an upper surface and a lower surface and two side surfaces connecting the upper surface and the lower surface are formed between one side and the other side from which electrode leads protrude respectively, and the housing frame includes a top frame covering an upper surface of the battery cell stack; a bottom frame covering a lower surface of the battery cell stack; and a side frame covering a side surface of the battery cell stack; and a flame retardant sheet made of a material having fire resistance or flame retardancy is laminated between the top frame and the battery cell stack.

[0032] The above flame retardant sheet is formed with a fastening portion that restrains the end of the protective pad, and the fastening portion includes two protrusions between which the end of the protective pad is placed.

[0033] In addition, a plurality of secondary battery modules provided in the present invention can be electrically connected to each other and provided as a secondary battery pack.

[0034]

[0035] The present invention having the above configuration comprises a pad portion made of a material that is fire-resistant or flame-retardant and elastic, and a rigid portion made of a material that has a plate shape and has greater rigidity than the pad portion, thereby preventing the protection pad from bending in the event of a fire. Accordingly, flame propagation and movement of dust (generated by fire) can be prevented, thereby suppressing the possibility of thermal runway and blocking the occurrence of a short circuit, thereby reducing the risk of explosion of the secondary battery module.

[0036] The above-mentioned pad portion is laminated in two pieces to cover one side and the other side of the rigid portion with the rigid portion in between, and the protective pad is fitted into the fitting groove while covering the entire one side and the other side of the rigid portion. In addition, the fitting groove is provided so as to be formed with a slope so that the size gradually increases from one side where the end of the protective pad enters to the other side. Accordingly, the protective pad is allowed to move and elastically deform due to the shape of the fitting groove while being fitted into the fitting groove. That is, in the present invention, the protective pad can move in a wider range while being fixed to the busbar assembly, and thus can more efficiently absorb the shrinkage and expansion of the battery cell, thereby improving stability.

[0037] The above busbar assembly has a chamber portion, which is an empty space, between the busbar and the fitting groove, so that when an external impact is applied, the impact transmitted to the battery cell assembly can be cushioned.

[0038] The plurality of bucket sections are arranged in parallel along the longitudinal direction of the busbar assembly, and a chamber section forming a space between the outer surface and the inner surface of each bucket section is provided. Accordingly, the point where the protective pad is connected to the busbar assembly is close to the battery cell assembly (since the space for flame and dust to move becomes smaller), so the possibility of thermal runaway and short circuit can be further reduced.

[0039] Between the outer and inner surfaces of the bucket section, ribs are formed to protrude from the surface to reinforce rigidity or to partition the chamber section. Accordingly, the rigidity of the bucket section can be manufactured to meet the required conditions.

[0040]

[0041] FIG. 1a is a drawing sequentially showing the appearances of assembling a secondary battery module according to a conventional method, that is, the appearance of a battery cell stack, the appearance of the battery cell stack being housed in a housing frame and a bus bar assembly being coupled in an inner and outer direction, the appearance of an insulating cover being coupled to the outer side of the bus bar assembly, and the appearance of an end plate being coupled to the outer side of the insulating cover.

[0042] Figure 1b is a drawing showing a cross-sectional view when a fire occurs at the point where the battery cell stack and the bus bar assembly come into contact in an assembled state as in Figure 1a.

[0043] FIG. 2 is a drawing showing a cross-sectional view of a point where a battery cell stack and a bus bar assembly are in contact in a secondary battery module provided in the present invention.

[0044] Figure 3a is a drawing showing the inner side (the side facing the battery cell stack) of the busbar assembly provided in the present invention.

[0045] Figure 3b is a drawing showing the outer side (side where the busbar is coupled) of the busbar assembly provided in the present invention.

[0046] FIG. 4 is a cross-sectional view showing electrode leads protruding from a battery cell stack in a secondary battery module provided in the present invention and connected to a bus bar assembly.

[0047] Figure 5 is a drawing showing an enlarged view of the part indicated by a dotted line in Figure 4.

[0048] FIG. 6 is a cross-sectional view showing a protective pad of a battery cell stack in a secondary battery module provided in the present invention, which is restrained by a protrusion of a flame retardant sheet coupled to a housing frame.

[0049] Figure 7 is a drawing showing an enlarged view of the part indicated by a dotted line in Figure 6.

[0050]

[0051] Hereinafter, the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0052] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0053] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0054] The present invention relates to a secondary battery module in which the rigidity of a protective pad is reinforced to prevent a fire from progressing into thermal runaway, a chamber is provided in a busbar assembly to protect a battery cell assembly from external impact, and the movement of flames and dust is suppressed. Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0055] The present invention relates to a secondary battery module capable of minimizing the gap between a battery cell stack and a busbar assembly to suppress or delay the progression to thermal runaway as much as possible, and preventing the problem of a protection pad coming off from the busbar assembly. Hereinafter, embodiments provided by the present invention will be described in more detail with reference to the attached drawings.

[0056] The secondary battery module provided in the present invention is configured to include a battery cell stack (10), a housing frame (50), and a bus bar assembly (300).

[0057] (Referring to FIG. 1a), the battery cell stack (10) provided in the present invention is configured by stacking a plurality of battery cells (12), and the battery cells (12) are provided as a pouch-type secondary battery, and the battery cell (12) is configured such that both electrode leads (positive electrode lead, negative electrode lead) protrude from the same end, or one protrudes from one end and the other protrudes from the other end.

[0058] In addition, a protective pad (11) is inserted between adjacent battery cells (12) to protect the battery cells (12) from external temperature changes, mechanical loads, external shocks and vibrations and to absorb volume changes due to shrinkage and expansion during charging and discharging of the battery cells (12).

[0059] That is, each protective pad (11) is inserted so as to be placed between neighboring battery cells (12), and depending on the use and design of the secondary battery module, one, two, or more battery cells (12) are placed between neighboring protective pads (11).

[0060] And, the housing frame (50) is coupled to cover the surfaces of the battery cell stack (10) except for the two surfaces from which the electrode leads protrude (the two surfaces from which the electrode leads protrude). That is, the battery cell stack (10) is accommodated inside the housing frame (50).

[0061] Referring to FIGS. 1A and 6, the battery cell stack (10) is provided in a shape in which an upper surface and a lower surface and two side surfaces connecting the upper surface and the lower surface are formed between one side and the other side from which electrode leads protrude, respectively, and the housing frame (50) includes a top frame (50a) covering the upper surface of the battery cell stack (10); a bottom frame (50c) covering the lower surface of the battery cell stack; and a side frame (50b) covering the side surface of the battery cell stack (10). In addition, in order to secure insulation from the outside and prevent or delay the spread of fire, a flame retardant sheet (40) made of a material having fire resistance or flame retardancy is bonded to at least the top frame (50a) among the top frame (50a), the bottom frame (50c), and the side frame (50b). Accordingly, the flame retardant sheet (40) is positioned between the housing frame (50) and the battery cell stack (10).

[0062] And, the bus bar assembly (30) is coupled to the housing frame (50) so as to cover the exposed surface in the direction in which the electrode leads protrude from the battery cells (12). At this time, the bus bar assembly (30) has a bus bar (35) on the outer surface to which the electrode leads are electrically connected, and a fitting groove (31) is formed on the inner surface, so that when coupled to the housing frame (50), the end of the protection pad (11) is fitted into the fitting groove (31) and fixed.

[0063] In addition, when the busbar assembly (30) is combined, the insulating cover (60) and the end plate (20) are sequentially combined to the outer surface of the busbar assembly (30) as in the conventional structure.

[0064]

[0065] First embodiment

[0066]

[0067] In the present invention, a first embodiment is provided with a configuration having an improved protective pad (11) that can prevent a fire from spreading to a neighboring battery cell (12) when a fire occurs in a battery cell (12).

[0068] FIG. 2 is a drawing showing a cross-sectional view of a point where a battery cell stack (10) and a bus bar assembly (30) come into contact in a secondary battery module provided in the present invention.

[0069] Referring to FIG. 2, the protective pad (11) provided in this embodiment includes a pad portion (11b) made of a material having fire resistance or flame retardancy and elasticity, and a rigid portion (11a) made of a material having a plate shape and having greater rigidity than the pad portion (11b).

[0070] The above rigid body (11a) may be made of metal or engineering plastic, but is manufactured to have sufficiently greater rigidity than the pad portion (11b). In addition, it is manufactured to enable appropriate elastic deformation (e.g., bending) according to the contraction and expansion of the battery cells (12) arranged on both sides.

[0071] In addition, the pad portion (11b) may be manufactured from the same material as the conventional protective pad, such as a synthetic resin material such as polyurethane, polypropylene, or silicone, so as to have the same characteristics as the conventional protective pad, but the thickness and detailed specifications (elastic deformation amount, etc.) may be determined according to the required specifications.

[0072] In this embodiment, the pad portion (11b) is laminated in two pieces so as to cover one side and the other side of the rigid portion (11a) with the rigid portion (11a) in between. That is, the protective pad (11) is fitted into the fitting groove (31) with the pad portion (11b) covering the entire one side and the other side of the rigid portion (11a).

[0073] The above fitting groove (31) is formed with a slope (32) so that the size gradually increases from one side where the end of the protection pad (11) enters to the other side, so that the protection pad (11) is allowed to move and elastically deform (bend) due to the shape of the fitting groove (31) when fitted into the fitting groove (31).

[0074] In addition, a gap of a predetermined size can be provided between the end of the protective pad (11) and the fitting groove (31).

[0075] Accordingly, even if a fire occurs on one side of the protective pad (11), the rigid portion (11a) having greater rigidity can support the pressure, thereby preventing the fire from spreading to the other side. That is, the protective pad (11) provided in this embodiment can prevent flame spread and dust movement because the rigid portion (11a) can maintain its original shape, thereby suppressing the possibility of thermal runway and preventing the occurrence of a short circuit.

[0076] In addition, the fitting groove (31) that restrains the end of the protective pad (11) is formed with a slope (32) so that the size gradually increases from one side where the end of the protective pad (11) enters to the other side, and a gap of a certain size is formed (within a range that prevents the protective pad from coming off), so that when shrinkage and expansion of the battery cell (12) occur, the protective pad (11) can move in a wider range and absorb the volume change of the battery cell (12).

[0077]

[0078] Second embodiment

[0079]

[0080] In the present invention, a second embodiment is provided in which a gap between a battery cell assembly (10) and a busbar assembly (30) can be reduced to reduce the possibility of a fire spreading to a neighboring battery cell (12) when a fire occurs in a battery cell (12), and a configuration is provided in which a busbar assembly (30) can more effectively protect a battery cell stack (10) from an external impact.

[0081] FIG. 3a is a drawing showing the inner side (the side facing the battery cell stack) of the busbar assembly (30) provided in the present invention, and FIG. 3b is a drawing showing the outer side (the side where the busbar is coupled) of the busbar assembly (30) provided in the present invention. In addition, FIG. 4 is a drawing showing a cross-sectional view showing the electrode leads (12a) protruding from the battery cell stack (10) in the secondary battery module provided in the present invention connected to the busbar assembly (30), and FIG. 5 is a drawing showing an enlarged view of a portion indicated by a dotted line in FIG. 4. FIG. 6 is a cross-sectional view showing a protective pad (11) of a battery cell stack (10) provided in a secondary battery module according to the present invention, which is restrained by a protrusion (41) of a flame-retardant sheet (40) coupled to a housing frame (50), and FIG. 7 is a view showing an enlarged view of a portion indicated by a dotted line in FIG. 6.

[0082] Referring to FIGS. 3a and 3b, the bus bar assembly (30) provided in this embodiment is configured to include a plurality of bucket parts (33) that form a closed or open space between the inner side facing the battery cell stack (10) and the outer side opposite thereto when combined with the housing frame (50).

[0083] The above bucket part (33) has a shape formed long in the vertical direction (see the direction indication in FIG. 1a) as shown in FIG. 3a, and is arranged in a plurality of rows in a parallel manner along the longitudinal direction (the direction corresponding to the width direction based on FIG. 1a or the left-right direction based on FIG. 3a) of the bus bar assembly (30).

[0084] The bucket portion (33) has an inwardly convex surface, and a chamber portion (34) forming a space is provided inside. That is, as shown in FIGS. 2, 4, and 5, the busbar assembly (30) has a fitting groove (31) formed inwardly toward the battery cell stack (10), a busbar (35) is coupled from the outside, and the chamber portion (34), which is an empty space, is provided between the busbar (35) and the fitting groove (31).

[0085] In addition, a metal bus bar (35) is attached to the outer surface of all of the bucket parts (33) or the outer surface of selected bucket parts (33). Each of the bus bars (35) is electrically connected to a terminal that is connected to an external charging / discharging device.

[0086] Meanwhile, a slit (36) penetrating the inner and outer surfaces of the busbar assembly (30) is formed between adjacent bucket sections (33) in the busbar assembly (30) as shown in FIG. 2, and the electrode lead (12a) protruding from each battery cell (12) passes through the busbar assembly (30) through the slit (36) and is then connected to the busbar (35) through welding as shown in FIGS. 4 and 5.

[0087] The fitting groove (31) into which the end of the protective pad (11) laminated on the above battery cell laminate (10) is fitted and restrained is formed on an inwardly convex surface of the bucket portion (33). At this time, the fitting groove (31) may be formed in all bucket portions (33) or may be formed only in pre-selected bucket portions (33).

[0088] In addition, a rib (37) is formed between the outer and inner surfaces of the bucket portion (33) to protrude from the surface to reinforce rigidity and to partition the chamber portion (34). The thickness, length, and shape of the rib (37) can be determined according to the rigidity required in the busbar assembly (30) and the size and shape of the chamber portion (34).

[0089] In addition, as described above, the battery cell stack (10) is provided in a shape in which an upper surface and a lower surface and two side surfaces connecting the upper surface and the lower surface are formed between one side and the other side from which the electrode leads (12a) protrude respectively. The housing frame (50) provided in this embodiment is configured to include a top frame (50a) covering the upper surface of the battery cell stack (10), a bottom frame (50c) covering the lower surface of the battery cell stack (10), and a side frame (50b) covering the side surface of the battery cell stack (10), as illustrated in FIG. 6.

[0090] And, a flame retardant sheet (40) is bonded to the inside of the top frame (50a). Accordingly, a flame retardant sheet (40) made of a material having fire resistance or flame retardancy is positioned between the top frame (50a) and the battery cell laminate (10).

[0091] The flame retardant sheet (40) is formed with a fastening portion (41) to restrain the upper end of the protective pad (11). As illustrated in FIG. 7, the flame retardant sheet (40) has a thin thickness, making it difficult to form the fastening portion (41) in a groove shape. Accordingly, the flame retardant sheet (40) provided in this embodiment is partially bent as illustrated to form the fastening portion (41) in the shape of protrusions (41a, 41b).

[0092] The protrusions (41a, 41b) formed on the above flame retardant sheet (40) are formed in two pieces spaced apart from each other to form a groove between them, and the end of the protective pad (11) is fitted between the protrusions (41a, 41b).

[0093] The busbar assembly (30) provided in this embodiment has a chamber portion (34), which is an empty space, provided between the busbar (35) and the fitting groove (31), so that when an external impact is applied, the impact transmitted to the battery cell assembly (10) can be cushioned.

[0094] In addition, in the present invention, a plurality of secondary battery modules having the technical features of the first and second embodiments described above can be electrically connected to provide a secondary battery pack.

[0095]

[0096] The present invention having the above configuration comprises a pad portion (11b) made of a material having fire resistance or flame retardancy and elasticity, and a rigid portion (11a) having a plate shape and made of a material having greater rigidity than the pad portion (11b), so that the protection pad (11) can be prevented from being bent when a fire occurs. Accordingly, flame spread and movement of dust (generated by fire) can be prevented, thereby suppressing the possibility of thermal runway and blocking the occurrence of a short circuit, thereby reducing the risk of explosion of the secondary battery module.

[0097] The above pad portion (11b) is laminated in two pieces to cover one side and the other side of the rigid portion (11a) with the rigid portion (11a) in between, so that the protective pad (11) covers the entire one side and the other side of the rigid portion (11a) and is fitted into the fitting groove (31). In addition, the fitting groove (31) is provided so that an incline (32) is formed so that the size gradually increases from one side where the end of the protective pad enters to the other side. Accordingly, the protective pad (11) is allowed to move and elastically deform due to the shape of the fitting groove (31) when it is fitted into the fitting groove (31). That is, in the present invention, the protective pad (11) can move in a wider range while being fixed to the busbar assembly (30), and thus can more efficiently absorb the contraction and expansion of the battery cell (12) and improve stability.

[0098] The above busbar assembly (30) has a chamber portion (34), which is an empty space, provided between the busbar (35) and the fitting groove (31), so that when an external impact is applied, the impact transmitted to the battery cell assembly (10) can be cushioned.

[0099] The plurality of bucket parts (33) are arranged in parallel along the longitudinal direction of the bus bar assembly (30), and a chamber part (34) forming a space between the outer surface and the inner surface of each bucket part (33) is provided. Accordingly, the point where the protection pad (11) is connected to the bus bar assembly (30) is close to the battery cell assembly (10) (since the space through which flame and dust move becomes smaller), so that the possibility of thermal runaway and short circuit can be further reduced.

[0100] Between the outer and inner surfaces of the bucket portion (33), a rib (37) is formed to protrude from the surface or to partition the chamber portion to reinforce rigidity. Accordingly, the rigidity of the bucket portion (33) can be manufactured to meet the required conditions.

[0101] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0102]

[0103] [Explanation of symbols]

[0104] 10: Battery cell stack

[0105] 11: Protective pad

[0106] 12: Battery cell

[0107] 20: Endplate

[0108] 30: Busbar assembly

[0109] 40: Flame retardant sheet

[0110] 50: Housing frame

Claims

1. A battery cell laminate in which a plurality of battery cells with protruding electrode leads and a plurality of protective pads are laminated, each protective pad being inserted so as to be placed between neighboring battery cells; A housing frame in which the battery cell stack is accommodated so as to cover surfaces other than the surface from which the electrode leads protrude in the battery cell stack; and A bus bar assembly is formed by being connected to the housing frame so as to cover the direction in which the electrode leads protrude from the battery cells, and has a bus bar to which the electrode leads are electrically connected, and has a fitting groove formed into which the ends of the protection pads are fitted and fixed; A secondary battery module including a pad portion made of a material having fire resistance or flame retardancy and elasticity, and a rigid portion having a plate shape and made of a material having greater rigidity than the pad portion.

2. In paragraph 1, The above pad portion is a secondary battery module in which two are laminated to cover one side and the other side of the rigid body portion with the rigid body portion in between.

3. In paragraph 2, A secondary battery module in which the protective pad is fitted into the insertion groove while the pad portion covers one side and the other side of the rigid body portion.

4. In paragraph 3, The above-mentioned insertion groove is formed with a slope so that the size gradually increases from one side where the end of the protective pad enters to the other side. The above protective pad is a secondary battery module that allows movement and elastic deformation according to the shape of the fitting groove when fitted into the fitting groove.

5. In any one of paragraphs 1 to 4, The above busbar assembly has a groove formed on the inside facing the battery cell stack, and a busbar is joined on the outside. A secondary battery module having a chamber portion, which is an empty space, between the bus bar and the insertion groove.

6. In paragraph 5, The above busbar assembly includes a plurality of bucket parts having an inwardly convex surface, and the plurality of bucket parts are arranged in parallel along the longitudinal direction of the busbar assembly. A secondary battery module having a chamber section forming a space within each bucket section.

7. In paragraph 6, A secondary battery module having a bus bar attached to the outer side of selected bucket parts among the above bucket parts.

8. In paragraph 7, A secondary battery module in which a slit is formed between adjacent buckets and penetrates the inner and outer surfaces of the busbar assembly, and the electrode leads protruding from each battery cell are connected to the busbar through the slit.

9. In paragraph 6, The above bucket parts are secondary battery modules having a groove formed on the convex surface facing inward.

10. In paragraph 6, A secondary battery module having ribs formed within the bucket section to protrude from the surface to reinforce rigidity or to partition the chamber section.

11. In any one of paragraphs 1 to 4, The above battery cell laminate is provided in a shape in which two side surfaces are formed, connecting the upper and lower surfaces and the upper and lower surfaces, between one side and the other side from which the electrode leads protrude respectively. The housing frame includes a top frame covering the upper surface of the battery cell stack; a bottom frame covering the lower surface of the battery cell stack; and a side frame covering the side surface of the battery cell stack. A secondary battery module in which a flame retardant sheet made of a fire-resistant or flame-retardant material is laminated between the top frame and the battery cell laminate.

12. In paragraph 11, The above flame retardant sheet is formed with a fastening part that restrains the end of the protective pad, A secondary battery module wherein the above-mentioned fastening member includes two protrusions between which the ends of the protective pad are placed.

13. A secondary battery pack in which a plurality of secondary battery modules of clause 1 are electrically connected.

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