Battery pack and electric vehicle

Abstract

The utility model relates to the field of batteries, and particularly provides a battery pack and an electric vehicle, the battery pack is provided with a box body comprising a lower shell bottom plate and a beam structure, a battery core stacking body which is arranged in the box body and is formed by stacking a plurality of soft package battery cores, and a tab which extends from the end part of the soft package battery core to the beam structure along the length direction of the soft package battery core, the heat-conducting structural adhesive is arranged between the battery cell stacking body and the bottom plate of the lower shell; and the polystyrene foam is filled between the tab and the beam structure. According to the scheme, the soft-package CTP battery pack can be constructed based on the soft-package battery cells, the battery cell stack formed by stacking the soft-package battery cells is well protected, and the battery pack is easy to assemble, so that the overall stability of the battery pack is better.

Description

[0001] This application claims priority to Chinese patent application number 202311785202.7, the contents of which are incorporated herein by reference. Technical Field

[0002] The utility model relates to the technical field of power batteries, in particular to a battery pack and an electric vehicle integrated with the battery pack. Background Art

[0003] The operating voltage of a single secondary battery is approximately 2.5V to 4.5V. In electric vehicles or energy storage systems that require large capacity and high voltage output, it is usually necessary to connect multiple battery cells in series and / or in parallel to form a battery module, and then connect the battery modules in series and / or in parallel to form a battery pack, and further use the battery pack as an energy system for powering electric vehicles or as an energy storage system. The number and shape of the battery modules used to build the battery pack, as well as the number and shape of the battery cells used to make up the battery module, can be flexibly changed according to actual needs.

[0004] In the field of power batteries used in electric vehicles, to improve the vehicles' full-charge range and charging speed, it is necessary to further enhance the energy density and cooling performance of the battery pack. As a solution to improve energy density, CTP (cell to pack) battery packs omit the step of forming battery cells into battery modules and directly integrate the battery cells into the battery pack. This eliminates the structural components and electrical connectors required to form the battery module, leaving more space for the battery cells themselves.

[0005] Currently, common battery cells are categorized by structure into cylindrical, prismatic, and soft-pack battery cells. CTP battery packs using prismatic cells have been widely adopted, but soft-pack batteries, due to their inability to withstand external impacts and poor assembly, still face a series of challenges during integration into CTP battery packs. In existing technologies, directly installing a stack of soft-pack batteries within a battery pack is cumbersome and difficult to effectively protect, resulting in poor overall stability. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a battery pack that is easy to assemble and has better overall stability.

[0007] To achieve the above-mentioned objectives and other related objectives, the present invention provides a battery pack, comprising a box body having an installation space; a cell stack body, the cell stack body comprising a plurality of stacked soft-pack cells, the cell stack body being arranged in the installation space; and at least two colloid structures, the colloid structures being arranged in the installation space, and the colloid structures being directly connected between the cell stack body and the box body.

[0008] Optionally, the box body includes a lower shell, the lower shell includes a lower shell bottom plate and a beam structure, the battery cell stack is arranged on the lower shell bottom plate, and the colloid structure is filled between the battery cell stack and the lower shell bottom plate and between the battery cell stack and the beam structure.

[0009] Optionally, one colloid structure is constructed as a first glue layer and is filled and bonded between the bottom of the battery cell stack and the bottom plate of the lower shell, and the other colloid structure is constructed as a second glue layer and is filled and bonded between the tab side of the battery cell stack and the beam structure.

[0010] Optionally, the first adhesive layer is a thermally conductive structural adhesive.

[0011] Optionally, the second adhesive layer is foamed adhesive.

[0012] Optionally, the beam structure includes: a side beam, a portion of the tab of each soft-pack battery cell faces the side beam, and the second adhesive layer is arranged between the tab and the side beam.

[0013] Optionally, the beam structure further includes one or more box middle beams, another portion of the tabs of the soft-pack battery cell faces the box middle beams, and the second adhesive layer is further arranged between the tabs and the box middle beams.

[0014] Optionally, one or more box middle beams divide the lower shell bottom plate into multiple areas, and there are multiple battery cell stacks, each of which is arranged in one of the areas.

[0015] Optionally, the height H1 of the foam glue, the height H2 of the tab, and the height H3 of the main body of the soft-pack battery cell satisfy the following formula: H2≤H1≤H3.

[0016] Optionally, the second adhesive layer wraps the tabs of the soft-pack battery cell.

[0017] Optionally, the density of the foamed rubber is a, 0.2≤a≤0.3 g / cm3, the elastic modulus is b, 10≤b≤30 MPa, the shear strength is c, 1≤c≤3 MPa, and the tensile strength is d, 1≤d≤3 MPa.

[0018] Optionally, the battery pack further includes side plates, which are arranged on both sides of the battery cell stack along the stacking direction of the soft-pack battery cells in the battery cell stack.

[0019] Optionally, the side plate is sandwiched between the battery cell stack and the box.

[0020] Optionally, the battery pack further includes: structural adhesive, and the box body further includes: an upper cover, the upper cover is provided on the lower shell to define the installation space therebetween, and the upper cover and the battery cell stack are directly bonded and fixed by the structural adhesive.

[0021] Optionally, the second adhesive layer is also filled between the tabs of adjacent soft-pack battery cells.

[0022] <Beneficial Effects>

[0023] The technical solution provided by the present invention can construct a soft-pack CTP battery pack based on soft-pack batteries, has a good protective effect on the battery stack formed by stacking the soft-pack batteries, and is easy to assemble.

[0024] A second aspect of the present application provides an electric vehicle having the battery pack provided by the first aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the stacking distribution of soft-pack CTP battery packs provided in some embodiments of the present invention.

[0026] Figure 2 yes Figure 1 A schematic diagram of the stacking distribution of a modified example of an implementation method.

[0027] Figure 3 Is to use Figure 1 Exploded diagram of a soft-pack CTP battery pack with corresponding stack distribution.

[0028] Figure 4 It is a schematic structural diagram (top view) of the side panels in some embodiments of the present invention.

[0029] Figure 5 yes Figure 4 A schematic structural diagram of the outer surface of the side panel in an embodiment.

[0030] Figure 6 It is a structural schematic diagram of the outer surface of the side panel provided in other embodiments of the present invention.

[0031] Figure 7 yes Figure 6 Schematic diagram of the matching structure between the side panels and the long side beams of the box body in the assembled state in the embodiment.

[0032] Figure 8 Schematic diagram of an explosion of a soft-pack CTP battery pack with a limiting portion in some embodiments.

[0033] Figure 9 yes Figure 8 A top view of a box body equipped with a limiting portion in an embodiment.

[0034] Figure 10 yes Figure 8 Schematic diagram of the relative position relationship between the bottom of the soft-pack battery cell and the limiting portion when assembly is completed in an embodiment.

[0035] Figure 11 It is a structural schematic diagram (exploded view) of a soft-pack CTP battery pack in other embodiments of the present invention.

[0036] Figure 12 yes Figure 10 Schematic diagram of the position of the limiting portion at the bottom of the box in an embodiment.

[0037] Figure 13 Schematic diagram (cross-sectional view) of the relative positional relationship between the soft-pack battery cell, the bottom plate of the lower shell, and the limiting portion of another embodiment.

[0038] Figure 14 It is a schematic diagram of the foam filling position in some embodiments of the present invention.

[0039] Figure 15 yes Figure 14 Schematic diagram of the foam filling structure between the soft-pack battery cell and the short side beam in an embodiment (partial cross-sectional view along the XY plane).

[0040] Figure 16 yes Figure 14 Schematic diagram of the foam filling height between the soft-pack battery cell and the short side beam in an embodiment (partial cross-sectional view along the XZ plane).

[0041] Figure 17 2. It is a structural schematic diagram (exploded view) of a soft-pack CTP battery pack provided with a glue blocking portion in some embodiments.

[0042] Figure 18 yes Figure 17 Schematic diagram of the structure after the rubber stop portion is compressed in an embodiment.

[0043] Figure 19 yes Figure 17 Schematic diagram of the structure of each component in the box in an embodiment (top view after removing the upper cover).

[0044] Figure 20 yes Figure 19 A partial enlarged cross-sectional view of area A in the middle.

[0045] Reference numerals:

[0046] Soft-pack CTP battery pack 100, 200, 300, 400, 500, 600; box 1; lower shell 11; upper cover 12; lower shell bottom plate 13; side beam 14; long side beam 141; short side beam 142; box middle beam 15; chamber 16; first chamber 161; second chamber 162; insulating sheet 17; battery cell stack 2; soft-pack battery cell 23; tab 231; tab overlap surface 232; side plate 24; groove 241; inner surface 242; outer surface 243; outer edge limit portion 244; flat surface 245; first A first reinforcing rib 246; a second reinforcing rib 247; a positioning column 248; a positioning groove 249; a thermally conductive structural adhesive 25; a limiting portion 26; an insulating film 261; a rubber stop portion 27; a tooth 271; a flexible circuit board 28; a foam adhesive 29; a first battery cell stack 21; a second battery cell stack 22; a first output positive electrode 311; a first output negative electrode 312; a second output positive electrode 321; a second output negative electrode 322; a third output positive electrode 331; a third output negative electrode 332; an end output electrode base 34; a middle adapter base 35; and an adapter copper bar 36. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] like Figures 1-20 As shown, according to some embodiments of the present invention, there is an installation space (chamber 16) in the box 1, the battery cell stack 2 includes a plurality of stacked soft-pack battery cells 23, the battery cell stack 2 is arranged in the installation space, at least two colloid structures, the colloid structure is arranged in the installation space, and the colloid structure is directly connected between the battery cell stack 2 and the box 1 to ensure the stable arrangement of the battery cell stack 2 in the installation space.

[0049] Furthermore, the box body 1 includes a lower shell 11, the lower shell 11 includes a lower shell bottom plate 13 and a beam structure, the battery cell stack 2 is arranged on the lower shell bottom plate 13, and the colloid structure is filled between the battery cell stack 2 and the lower shell bottom plate 13 and between the battery cell stack 2 and the beam structure.

[0050] Among them, one colloid structure is constructed as a first glue layer and is filled and bonded between the bottom of the battery cell stack 2 and the lower shell bottom plate 13, and the other colloid structure is constructed as a second glue layer and is filled and bonded between the tab side of the battery cell stack 2 and the beam structure.

[0051] Specifically, the first adhesive layer is thermally conductive structural adhesive, and the second adhesive layer is foam adhesive.

[0052] Furthermore, the beam structure includes: side beams 14, a portion of the tabs 231 of each soft-pack battery cell 23 faces the side beams 14, and a second adhesive layer is provided between the tabs 231 and the side beams 14. The beam structure also includes one or more box-body middle beams 15, another portion of the tabs 231 of the soft-pack battery cell 23 faces the box-body middle beams 15, and the second adhesive layer is further provided between the tabs 231 and the box-body middle beams 15. The second adhesive layer also fills between the tabs 231 of adjacent soft-pack battery cells 23.

[0053] The one or more box middle beams 15 divide the lower shell bottom plate 13 into multiple areas, and there are multiple battery cell stacks 2, each of which is arranged in one area.

[0054] Preferably, the second adhesive layer wraps the tab 231 of the soft-pack battery cell 23 to provide insulation protection for the tab 231 .

[0055] Furthermore, the battery pack further includes side panels 24 , which are arranged on both sides of the cell stack 2 along the stacking direction of the soft-pack cells 23 in the cell stack 2 . The side panels 24 are sandwiched between the cell stack 2 and the box 1 .

[0056] The battery pack further includes: structural adhesive, and the box body 1 further includes: an upper cover 12, which is arranged on the lower shell 11 to define an installation space between the two, and the upper cover 12 is directly bonded and fixed to the battery cell stack 2 by structural adhesive.

[0057] <Cell Stack Distribution>

[0058] Figure 1 Schematic diagram of the stacking distribution of the soft-pack CTP battery pack 100 provided in some embodiments of the present invention.

[0059] refer to Figure 1 In some embodiments of the present invention, the soft-pack CTP battery pack 100 includes a square box body 1 and a square battery cell stack 2. The internal space of the box body 1 can accommodate two battery cell stacks 2 placed side by side.

[0060] The two battery cell stacks 2 are a first battery cell stack 21 and a second battery cell stack 22. The first battery cell stack 21 is provided with a first output positive electrode 311 and a first output negative electrode 312 at both ends of a side adjacent to the second battery cell stack 22. Correspondingly, the second battery cell stack 22 is provided with a second output positive electrode 321 and a second output negative electrode 322 at both ends of a side adjacent to the first battery cell stack 21. The positions of the first output positive electrode 311 and the second output negative electrode 322 correspond to each other, and the positions of the first output negative electrode 312 and the second output positive electrode 321 correspond to each other, thereby reducing wiring length and facilitating the series electrical connection between the two battery cell stacks 2.

[0061] In addition, the first cell stack 21 is further provided with a third output positive electrode 331 and a third output negative electrode 332 adjacent to each other at one end away from the second cell stack 22. The first output positive electrode 311, the first output negative electrode 312, the second output positive electrode 321, and the second output negative electrode 322 serve as electrodes electrically connected in series within the two cell stacks 2, while the third output positive electrode 331 and the third output negative electrode 332 serve as output electrodes for the entire soft-pack CTP battery pack 100. In some embodiments, the third output positive electrode 331 and the third output negative electrode 332 are electrically connected to the battery pack disconnect unit (BDU), which in turn supplies power to the entire vehicle through the battery pack disconnect unit.

[0062] The output electrodes provided by the above distribution and electrical connection method, namely the third output positive electrode 331 and the third output negative electrode 332 are adjacent to each other. In some cases, when the output electrodes of the entire soft-pack CTP battery pack 100 need to be separated from each other, the first battery cell stack 21 can be relatively Figure 1 Rotate 180 degrees and place it in the box 1, so as to obtain the following Figure 2 The assembly structure of the soft-pack CTP battery pack 200 is shown.

[0063] refer to Figure 2 By rotating 180° and then placing it into the box, the third output positive electrode 331 and the third output negative electrode 332 will be located adjacent to the second battery cell stack 22. The third output positive electrode 331 and the second output negative electrode 322 are electrically connected via a copper adapter bar 36, and the third output negative electrode 332 and the second output positive electrode 321 are electrically connected via another copper adapter bar 36, thereby achieving a high-voltage electrical connection between the first battery cell stack 21 and the second battery cell stack 22. The first output positive electrode 311 and the first output negative electrode 312 can then serve as the output electrodes of the entire soft-pack CTP battery pack 200. By using the first battery cell stack 21 and the copper adapter bar 36 with the above-mentioned electrode distribution, the installation angle of the first battery cell stack 21 can be flexibly adjusted to meet the requirements of different output electrode positions.

[0064] The above examples illustrate the distribution and electrical connection methods of the first cell stack 21 and the second cell stack 22 in some embodiments of the present invention. It is understood that the above description is merely exemplary and should not be construed as limiting the distribution and electrical connection methods. In other embodiments of the present invention, the first cell stack 21 and the second cell stack 22 can also be integrated into a single-row cell stack 2, and the location of each output electrode of the cell stack 2 can also be flexibly adjusted according to actual needs.

[0065] Figure 3 Is to use Figure 1 Exploded view of the soft-pack CTP battery pack 100 with corresponding stacking distribution.

[0066] refer to Figure 3 The square housing 1 includes a lower shell 11 and an upper cover 12. The lower shell 11 includes a rectangular lower shell bottom plate 13 and four side beams 14. The four side beams 14 are vertically fixed to the four sides of the rectangular lower shell bottom plate 13. The four side beams 14, the lower shell bottom plate 13 and the upper cover 12 together enclose a chamber (installation space) 16 for accommodating the battery cell stack 2. In addition to the four side beams 14, the housing 1 also includes a middle beam 15 arranged in the center of the longitudinal direction of the housing 1. The middle beam 15 divides the chamber 16 into a first chamber 161 and a second chamber 162. The first chamber 161 is used to accommodate the first battery cell stack 21, and the second chamber 162 is used to accommodate the second battery cell stack 22.

[0067] The bottom of the battery cell stack 2 and the bottom plate 13 of the lower shell are connected by structural glue or thermal conductive structural glue 25 ( Figure 3 Not shown, refer to Figure 8 In order to stabilize the cell stack 2, enhance the overall strength and rigidity of the battery pack, and protect against thermal runaway, a foaming glue 29 is also filled between the cell stack 2 and the side beams 14 or the middle beam 15 of the box body.

[0068] A structural adhesive, thermally conductive structural adhesive, or an elastomer component (not shown) is provided on the top of the cell stack 2 to fill the gap between the cell stack 2 and the upper cover 12. The structural adhesive, thermally conductive structural adhesive 25, and foam adhesive 29 between the bottom of the cell stack 2 and the bottom plate 13 of the lower housing, as well as the structural adhesive, thermally conductive structural adhesive, or elastomer component on the top of the cell stack 2, can form a stable and cushioning support for the cell stack 2 from all directions. In some embodiments, the elastomer component can be made of a composite of fireproof materials such as foam and mica, and double-sided tape or hot melt adhesive is provided between the elastomer component and the cell stack 2.

[0069] In some embodiments, a liquid cooling path (not shown) can be provided in the lower shell bottom plate 13 and the upper cover 12 , and the heat emitted by the battery cell stack 2 can be quickly transferred to the liquid cooling path using the thermal conductive structural adhesive 25 , thereby improving the cooling capacity of the battery cell stack 2 .

[0070] The four side beams 14 include two long side beams 141 and two short side beams 142. An end output pole base 34 is provided on the inner middle side of the short side beam 142 adjacent to the first battery cell stack 21. The copper bar (not shown) connected to the third output positive pole 331 and the copper bar (not shown) connected to the third output negative pole 332 are both provided on the end output pole base 34.

[0071] A central adapter base 35 is provided on the central beam 15 of the box. The copper bar connected to the first output positive electrode 311 and the copper bar connected to the second output negative electrode 322 are both provided on the central adapter base 35. One end of each adapter copper bar is also provided on the central adapter base 35 and electrically connected to the corresponding copper bar, thereby achieving electrical connection between the first battery cell stack 21 and the second battery cell stack 22.

[0072] <Battery cell stack>

[0073] Continue to refer Figure 3 In this embodiment, the cell stack 2 is formed by stacking and bonding multiple soft-pack cells 23. The stacking direction is the thickness direction of the soft-pack cells 23, that is, the width direction of the casing 1. The length direction of the soft-pack cells 23 is parallel to the length direction of the casing 1. The top and bottom of each soft-pack cell 23 are fully insulated with insulating tape (not shown).

[0074] The soft-pack cell 23 is a cell packaged with a plastic or flexible material such as an aluminum-plastic film, which has advantages such as light weight, low explosion resistance, and flexible design. The aluminum-plastic film may include a nylon layer, an aluminum layer, and a PP / CPP layer.

[0075] In some embodiments of the present invention, the size range of the soft-pack battery cell 23 used in the soft-pack CTP battery pack is: length 300-700mm, width 100-120mm, thickness 10-20mm. Figure 14 、 15 ) has a thickness of 0.2 to 0.6 mm and a width of 40 to 80 mm.

[0076] <Side Panel>

[0077] How to install the cell stack 2 into the box and apply pre-tightening force to the cell stack 2 in the initial state is a technical problem to be solved in the assembly process of the soft-pack CTP battery pack 100.

[0078] To solve the above problems, continue to refer to Figure 3 In some embodiments of the present invention, each cell stack 2 of the soft-pack CTP battery pack 100 has two opposite side panels 24. The two side panels 24 are respectively arranged on the inner side of the long side beams 141 at both ends of the width direction of the box body 1 (i.e., the two ends of the stacking direction of the cell stack 2), and are bonded and fixed to the main surface of the two soft-pack battery cells 23 at both ends of the stacking direction of the cell stack 2.

[0079] Figure 4 Schematic diagram (top view) of the structure of the side plate 24 in some embodiments of the present invention. Figure 4 The outer surface 243 of the side panel 24 has a groove 241 that cooperates with an external fixture. The external fixture (not shown) can use the groove 241 to clamp the side panel 24 and apply a preload force to the battery stack 2 from both ends of the battery stack 2 in the stacking direction, so that the battery stack 2 is squeezed to a size that can easily enter the box 1. Applying preload force can enhance the cycling performance of the battery cells. In addition, the groove 241 also facilitates the removal of the fixture after the battery stack 2 is placed in the box.

[0080] To ensure that the preload force is more evenly distributed across the pouch cell 23 and to avoid localized stress concentration, the portion of the inner surface 242 of the side panel 24 that contacts the main surface of the pouch cell 23 is formed as a flat surface 245. In other words, the area of ​​the flat surface 245 of the inner surface 242 of the side panel 24 is greater than the area of ​​the planar portion of the main surface of the pouch cell 23.

[0081] The outer edge of the inner surface 242 of the side plate 24 protrudes to form an outer edge limit portion 244, which is used to limit the relative position relationship between the side plate 24 and the soft-pack battery cell 23 when the flat surface 245 in the center of the inner surface 242 abuts against the main surface of the soft-pack battery cell 23.

[0082] The structure of the outer surface 243 of the side plate 24 is as follows Figure 5 Reference Figure 5 Second reinforcing ribs 247 are provided in the grooves 241 provided on the outer surface 243 of the side panel 24, while first reinforcing ribs 246 are provided in the areas where the grooves 241 are not provided. The number and density of the second reinforcing ribs 247 are greater than those of the first reinforcing ribs 246, thereby improving the strength of the area where the fixture mates. The second reinforcing ribs 247 are lower in height than the first reinforcing ribs 246, thus forming the grooves 241.

[0083] Optionally, the side panel 24 has a wall thickness of 1.5 to 5 mm and an overall width of 5 to 25 mm. The side panel 24 may be made of plastic materials such as PA6, PA66, PPE, and PBT.

[0084] Figure 6 2 is a schematic structural diagram of the outer surface 243 of the side panel 24 provided in some other embodiments of the present invention. Figure 7 Schematic diagram of the matching structure between the side panel 24 and the long side beam 141 of the box body 1 in the assembled state. Figure 6 and Figure 7 The inner wall of the long side beam 141 of the box body 1 is provided with a positioning column 248, and the outer surface 243 of the side panel 24 is provided with a positioning groove 249. The shapes and sizes of the positioning column 248 and the positioning groove 249 match each other. The positioning column 248 can be matched and inserted into the positioning groove 249 to limit the relative movement between the side panel 24 and the long side beam 141 along the length direction of the soft-pack battery cell 23, so that the positioning and installation of the battery cell stack 2 can be completed conveniently and accurately during assembly.

[0085] It should be noted that the groove 241 is only a form of cooperation with the external tooling fixture in this embodiment. In other embodiments of the present invention, depending on the type of tooling fixture, the outer surface 243 of the side panel can also be provided with any other suitable form of fixture cooperation part, as long as the fixture cooperation part can be used in conjunction with the tooling fixture so that the tooling fixture can stably clamp the battery cell stack 2.

[0086] The side plates 24 of the above structure can apply uniform pre-tightening force to the cell stack 2 in the initial state, effectively improving the grouping capability of the soft-pack cells 23 and facilitating the grouping of the soft-pack cells 23 and the placement of the cell stack 2 into a box.

[0087] <Thermal conductive structural adhesive 25-limiting portion 26>

[0088] During the assembly process, it is necessary to apply thermally conductive structural adhesive 25 between the bottom of the battery cell stack 2 and the bottom plate 13 of the lower shell. The thermally conductive structural adhesive 25 generally relies on external extrusion to spread it evenly and fill the gap. However, due to uneven extrusion force and other reasons, the thermally conductive structural adhesive 25 in some areas is usually too thin or too thick, affecting the heat dissipation efficiency and may affect the insulation performance.

[0089] Figure 8 FIG. 1 is an exploded view of a soft-pack CTP battery pack 300 with a limited portion 26 in some embodiments. Figure 8To address the above issues, some embodiments of the present invention further provide a stopper 26 of a specified height attached to the bottom plate 13 of the lower housing. When the housing 1 is placed horizontally, the top height of the stopper 26 is equal to or slightly lower than the height reached by a reasonable amount of thermally conductive structural adhesive 25 when it is leveled. In this way, a worker or an automated adhesive application system can determine whether the amount of adhesive applied is appropriate based on the relative height relationship between the liquid level of the thermally conductive structural adhesive 25 when it is leveled and the top height of the stopper 26. That is, when the liquid level of the added thermally conductive structural adhesive 25 is substantially flush with the top of the stopper 26, or slightly higher than the top of the stopper 26, the amount of thermally conductive structural adhesive 25 added is appropriate; otherwise, the amount of thermally conductive structural adhesive 25 added needs to be adjusted. Utilizing the stopper 26, the thickness of the thermally conductive structural adhesive 25 between the battery cell stack 2 and the housing 1 can be more accurately controlled to a specified thickness value within the range of 0.5 mm to 5 mm.

[0090] In some embodiments of the present invention, the limiting portion 26 is strip-shaped, i.e., a limiting strip. The limiting portion 26 is preferably made of an insulating material, such as an elastomer such as foam or silicone rubber, or a plastic such as PP or PPF. In other embodiments, the limiting portion 26 may be made of a high-strength metal material such as aluminum alloy or stainless steel, and insulation may be achieved by attaching an insulating film or spraying an insulating material onto the metal limiting portion 26.

[0091] In some embodiments, the limiting portion 26 can be formed by splicing multiple limiting bars, or can be formed by integrally molding multiple limiting bars. In other embodiments, the limiting portion 26 can also be integrally molded with the bottom plate 13 of the lower shell.

[0092] On the one hand, the limiting portion 26 can assist in controlling the amount of thermally conductive structural adhesive 25 added, improve the uniformity of the thermally conductive structural adhesive 25 at the bottom of the battery cell stack 2, enhance the heat dissipation capacity of the battery cell stack 2, and improve the safety under high current conditions; on the other hand, the limiting portion 26 can also separate the battery cell stack 2 and the lower shell bottom plate 13, ensuring that the bottom of the battery cell stack 2 will not directly contact the lower shell bottom plate 13 and affect the insulation.

[0093] refer to Figure 8 In some embodiments, the limiting portion 26 can be an independent component. After the limiting portion 26 is fixed to the bottom plate 13 of the lower shell, the area between the limiting portions 26 is filled with a thermal conductive structural adhesive 25 of the same height as the limiting portion 26 (or slightly higher than the height of the limiting portion 26). Then, the battery cell stack 2 is placed into the box 1. The thermal conductive structural adhesive 25 is squeezed through the battery cell stack 2 so that all soft-pack battery cells 23 are evenly in contact with the limiting portion 26 and the thermal conductive structural adhesive 25. In this embodiment, the limiting portion 26 is formed by a combination of multiple foam or silicone rubber strips. The surface of the bottom plate 13 of the lower shell is flat, and the limiting portion 26 is adhered to the surface of the bottom plate 13 of the lower shell.

[0094] Figure 9 2 is a top view of the box body 1 with the limit portion 26 installed. Figure 9 ,exist Figure 8 In the embodiment, the limiting portion 26 is a separately manufactured frame structure, including a rectangular limiting portion 26 constituting an outer frame, a limiting portion 26 connecting the rectangular diagonal lines, and a limiting portion 26 parallel to the short side beam 142 .

[0095] The heights of the various limiting portions 26 are equal and substantially equal to the rated glue coating height. Figure 10 2 is a schematic diagram of the relative position relationship between the bottom of the soft-pack battery cell 23 and the limiting portion 26 when the assembly is completed. Figure 9 and Figure 10 Because the limiting portion 26 extends in the width direction of the box body 1 and the extension range covers the extension range of the battery cell stack 2 in the width direction of the box body 1, the limiting portion 26 set in this way can effectively ensure that each soft-pack battery cell 23 of the battery cell stack 2 can be pressed against the limiting portion 26.

[0096] Figure 11 Schematic diagram (explosion diagram) of the structure of the soft-pack CTP battery pack 400 in other embodiments of the present invention. Figure 11 The limiting portion 26 can be integrally formed with the bottom plate 13 of the lower shell body. Specifically, the limiting portion 26 can be made on the surface of the bottom plate 13 of the lower shell body by punching ribs, or a glue groove can be punched on the surface of the bottom plate 13 of the lower shell body by punching pits. The side wall of the glue groove is higher than the bottom of the glue groove, that is, the side wall of the glue groove is equivalent to the limiting portion 26.

[0097] Figure 12 yes Figure 10 Schematic diagram of the position of the limiting portion 26 at the bottom of the box body 1 in the embodiment. Figure 13 yes Figure 10 Schematic diagram (cross-sectional view) of the relative position relationship between the soft-pack battery 23, the bottom plate 13 of the lower shell, and the limiting portion 26 in the embodiment. Figure 12 and 13 The limiting portion 26 extends along the width of the housing 1. The limiting portion 26 is integrally formed with the housing 1 and made of the same metal. To insulate the limiting portion 26, an insulating coating or an insulating film 261 may be sprayed on the surface of the limiting portion 26. By integrally forming the limiting portion 26, the step of separately positioning and installing the limiting portion 26 is eliminated, shortening the process and improving production efficiency.

[0098] <Foaming glue>

[0099] In order to improve the overall strength and rigidity of the soft-pack CTP battery pack 500 and ensure the structural safety performance of the soft-pack CTP battery pack 500, in some embodiments of the present invention, a foam glue 29 is also filled between the short side beam 142 and the battery cell stack 2.

[0100] Figure 14 Schematic diagram of the filling position of the foam glue 29 of the soft pack CTP battery pack 500 in some embodiments of the present invention. Figure 14 The foam glue 29 is filled at both ends of the length direction of the soft-pack battery cell 23, specifically between the short side beam 142 and the tab side of the battery cell stack 2, and between the middle beam 15 of the box body and the tab side of the battery cell stack 2.

[0101] The soft-packed cells 23 are stacked in an upright position in the thickness direction, and the length direction of the soft-packed cells 23 is the length direction of the box body 1. The two ends of the soft-packed cells 23 in the length direction extend with tabs 231, and the positive tab 231 and the negative tab 231 are respectively located at the two ends of the length direction of the soft-packed cells 23. The positive tabs 231 and the negative tabs 231 of the adjacent cells are rolled and bent and directly overlapped and welded to fix. In addition, in some embodiments, the cell stack 2 may further include a flexible circuit board 28 (refer to Figure 3 ), the body of the flexible circuit board 28 is arranged parallel to the tab 231 , and the sampling piece (not shown) of the flexible circuit board 28 is welded to the tab 231 .

[0102] Figure 15 Schematic diagram of the foam filling structure between the soft pack battery 23 and the short side beam 142 ( Figure 14 A cross-sectional view of a part along the XY plane). Figure 16 Schematic diagram of the filling height of the foam glue 29 between the soft-pack battery cell 23 and the short side beam 142 ( Figure 14 A cross-sectional view of a part along the XZ plane). Figure 15 and Figure 16 The adjacent tabs 231 are directly overlap-welded. After the tabs 231 are welded, foam glue 29 is poured between the tab side of the soft-pack battery cell 23 and the short side beam 142 and the middle beam 15 of the box body. After foaming and curing, the gaps between the battery cell stack 2 and the short side beam 142, and the gaps between the battery cell stack 2 and the middle beam 15 of the box body will be filled with foam glue 29.

[0103] After curing and molding, the height of the foam glue 29 is higher than the height of the pole ear 231. In this way, the foam glue 29 can completely wrap the pole ear 231 inside the foam glue 29, and the pole ears 231 are electrically isolated by the foam glue 29, thereby effectively preventing overlapping short circuits between the pole ears 231, and can improve the thermal runaway protection performance, improve safety and stability.

[0104] The height H1 of the foam glue, the height H2 of the tab 231, and the main body height H3 of the soft-pack battery cell 23 satisfy the following formula: H2 ≤ H1 ≤ H3. That is, in addition to completely submerging the tab 231, the height H1 of the foam glue is preferably less than or equal to the height H3 of the soft-pack battery cell. In other words, preferably, the tab height H2 ≤ the height H1 of the foam glue ≤ the height H3 of the soft-pack battery cell. Because the foam glue 29 can completely submerge the tab 231, when thermal runaway occurs, the high-temperature gas generated inside the soft-pack battery cell 23 will no longer be released from the tab 231. Instead, it will be released from the top of the tab 231 of the soft-pack battery cell 23 above the foam glue 29, effectively preventing the spread of thermal runaway.

[0105] In some embodiments of the present invention, the distance between the tab lap surface 232 connecting the tabs 231 and the short side beam 142 or the middle beam 15 of the box body is 3 to 10 mm, and the inner surface of the short side beam 142 and the middle beam 15 of the box body is provided with an insulating sheet 17, and the thickness of the insulating sheet 17 is 0.1 to 0.5 mm. The insulating sheet 17 can further ensure the electrical insulation between the tab 231 and the box body 1.

[0106] The density of the foam is a, 0.2≤a≤0.3g / cm3, the elastic modulus is b, 10≤b≤30MPa, the shear strength is c, 1≤c≤3MPa, and the tensile strength is d, 1≤d≤3MPa. That is, the density of the foam 29 after curing is 0.1~0.3g / cm 3 , elastic modulus 10 ~ 30MPa, shear strength and tensile strength range 1 ~ 3MPa, elongation at break ≥ 8%, compression modulus ≥ 30MPa, storage modulus ≥ 20MPa. In addition, the material of foam 29 also has insulation properties, volume resistivity ≥ 1×10 15 Ω·cm, flame retardant grade meets UL94 V0.

[0107] Through the above method, the foam glue 29 can, on the one hand, fix the battery cell stack 2 and increase the rigidity and strength of the soft-pack CTP battery pack 500; on the other hand, it can isolate the tab 231, including isolating the tab 231 from the high-temperature gas generated during thermal runaway, and realizing electrical insulation between the tabs 231 and between the tab 231 and the box body 1.

[0108] <Glue blocking section>

[0109] In order to prevent the foam glue 29 from invading between the battery cell stack 2 and the thermally conductive structural glue 25, affecting the heat dissipation capacity of the battery cell stack 2 or reducing the mechanical properties of the battery pack, in some embodiments of the present invention, a glue blocking portion 27 is also provided at a position where the foam glue 29 and the thermally conductive structural glue 25 may come into contact.

[0110] Figure 172 is a schematic structural diagram (exploded view) of a soft-pack CTP battery pack 600 provided with a glue blocking portion 27 in some embodiments. Figure 18 It is a schematic structural diagram of the rubber blocking portion 27 after being compressed.

[0111] refer to Figure 17 and Figure 18 The extending direction of the rubber blocking portion 27 is perpendicular to the length direction of the soft-pack battery core 23 , and both ends of the length direction of the rubber blocking portion 27 extend to abut against the inner side of the long side beam 141 .

[0112] Two rubber blocking parts 27 are respectively provided inside the first chamber 161 and the second chamber 162. The area for applying the thermal conductive structural adhesive 25 is located between the two rubber blocking parts 27, and the foaming adhesive 29 is filled between the rubber blocking part 27 and the short side beam 142, and between the rubber blocking part 27 and the middle beam 15 of the box body.

[0113] The length of the adhesive stop 27 is greater than or equal to the length of the battery cell stack 2 along the stacking direction, and less than the width of the casing 1. The width of the adhesive stop 27 is 1-30 mm. The top of the adhesive stop 27 is higher than the top of the thermally conductive structural adhesive 25 to limit the adhesive application area of ​​the thermally conductive structural adhesive 25 and prevent it from overflowing.

[0114] The rubber blocking portion 27 is preferably made of an insulating material with a certain degree of elasticity, such as foam, silicone rubber and other elastic materials, to effectively fill the gap, isolate the foaming rubber 29 and the thermal conductive structural rubber 25, and prevent the two rubbers from contacting each other.

[0115] The bottom of the rubber stopper 27 is flat and fits against the bottom plate 13 of the lower housing. The top can be formed into a flat, elastic surface. Since there is a certain gap between the soft-packed cells 23, when the soft-packed cells 23 squeeze the top plane of the elastic rubber stopper 27, a plurality of teeth 271 arranged at equal intervals along the length direction can be formed on the top of the rubber stopper 27. The tooth spacing between adjacent teeth 271 is equal to the thickness of one or a group of soft-packed cells 23. The rubber stopper 27 can be bonded and fixed to the cell stack 2 by each tooth 271 extending between adjacent soft-packed cells 23.

[0116] Figure 19 yes Figure 17 Schematic diagram of the structure of each component in the box 1 in the embodiment (top view). Figure 20 yes Figure 19 A partial enlarged cross-sectional view of area A in the middle.

[0117] refer to Figure 17 、 Figure 19 and Figure 20After the battery cell stack 2 is installed in place, the soft-pack battery cell 23 and the rubber blocking portion 27 are fully pressed together, and there is basically no gap between the bottom of the soft-pack battery cell 23 and the rubber blocking portion 27, thereby effectively isolating the foam glue 29 and the thermal conductive structural glue 25 to avoid contact between the two.

[0118] Through the above method, the glue blocking part 27 can form a close contact with the bottom of the battery cell stack 2, filling the gaps between the soft-pack battery cells 23, so that the foam glue 29 and the thermal conductive structural glue 25 are effectively isolated, preventing the foam glue 29 from invading between the thermal conductive structural glue 25 and the battery cell stack 2, thereby ensuring the heat dissipation performance of the battery cell stack 2 and the mechanical properties of the soft-pack CTP battery pack 600.

[0119] In other embodiments of the present invention, the glue blocking method of the glue blocking portion 27 includes but is not limited to filling the gap between adjacent soft-pack battery cells 23, filling the gap between the box body 1 and the battery cell stack 2, and wrapping the side of the soft-pack battery cell 23, etc., as long as it can help isolate the thermal conductive structural glue 25 and the foam glue 29.

[0120] <Assembly Process>

[0121] The above describes the assembly process of the soft-pack CTP battery pack provided in some embodiments of the present invention.

[0122] First, provide the lower housing 11 of the box 1. If the lower housing 11 has integrated limiters 26 or adhesive stops 27, apply the thermally conductive structural adhesive 25 directly between the limiters 26 of the lower housing 11. If the lower housing 11 does not have integrated limiters 26, provide additional limiters 26 or adhesive stops 27, and apply the thermally conductive structural adhesive 25 to the area between the additional limiters 26 or adhesive stops 27.

[0123] After applying a reasonable amount of thermally conductive structural adhesive 25, an external fixture is attached to the groove 241 of the side panel 24, and the two battery cell stacks 2 are placed in the box. Before placement, the battery cell stacks 2 are compressed to a certain size by the fixture, so that the overall width of the battery cell stack 2, including the side panel 24, is less than or equal to the width of the internal chamber 16 of the box body 1. After the battery cell stacks 2 are placed in the box, the fixture can be withdrawn through the groove 241 of the side panel 24, and the battery cell stack 2 slowly rebounds until the first reinforcing rib 246 of the side panel 24 contacts the long side beam 141, stopping the rebound.

[0124] After completing the installation of some electrical connectors, pour foam glue 29 between the short side beams 142 and the battery stack 2, and between the middle beam 15 of the box body and the battery stack 2. After the foam glue 29 is cured and the other electrical connectors and battery management system (if any) are installed, apply structural glue on the battery stack 2, close the upper cover 12, and complete the assembly of the soft pack CTP battery pack.

[0125] The above multiple embodiments provided by the present invention can be combined with each other. In some embodiments, the soft-pack CTP battery pack can also be directly integrated into the chassis of the electric vehicle, which is not limited in the embodiments of the present invention.

[0126] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A battery pack, characterized in that: include: A box body, wherein the box body has an installation space; A battery cell stack, the battery cell stack comprising a plurality of stacked soft-pack battery cells, the battery cell stack being arranged in the installation space; At least two colloid structures are provided in the installation space, and the colloid structures are directly connected between the battery cell stack and the box.

2. The battery pack according to claim 1, characterized in that: The box body includes a lower shell, the lower shell includes a lower shell bottom plate and a beam structure, the battery cell stack is arranged on the lower shell bottom plate, and the colloid structure is filled between the battery cell stack and the lower shell bottom plate and between the battery cell stack and the beam structure.

3. The battery pack according to claim 2, characterized in that: One of the colloid structures is constructed as a first glue layer and is filled and bonded between the bottom of the battery cell stack and the bottom plate of the lower shell, and the other colloid structure is constructed as a second glue layer and is filled and bonded between the ear side of the battery cell stack and the beam structure.

4. The battery pack according to claim 3, characterized in that: The first adhesive layer is a thermally conductive structural adhesive.

5. The battery pack according to claim 3, characterized in that: The second adhesive layer is foamed adhesive.

6. The battery pack according to claim 3, characterized in that: The beam structure comprises: a side beam, a portion of the pole ear of each of the soft-pack battery cells faces the side beam, and the second adhesive layer is arranged between the pole ear and the side beam.

7. The battery pack according to claim 6, characterized in that: The beam structure further includes one or more box middle beams, another portion of the tabs of the soft-pack battery core faces the box middle beams, and the second adhesive layer is further disposed between the tabs and the box middle beams.

8. The battery pack according to claim 7, characterized in that: One or more box middle beams divide the bottom plate of the lower shell into multiple areas, and there are multiple battery cell stacks, each of which is arranged in one of the areas.

9. The battery pack according to claim 5, characterized in that: The height H1 of the foam glue, the height H2 of the tab and the main body height H3 of the soft-pack battery cell satisfy the following formula: H2≤H1≤H3.

10. The battery pack according to claim 9, characterized in that: The second adhesive layer wraps the tabs of the soft-pack battery cell.

11. The battery pack according to claim 5, characterized in that: The density of the foam is a, 0.2≤a≤0.3g / cm 3 , the elastic modulus is b, 10≤b≤30MPa, the shear strength is c, 1≤c≤3MPa, and the tensile strength is d, 1≤d≤3MPa.

12. The battery pack according to claim 1, wherein: Also includes: Side plates are arranged on both sides of the battery cell stack along the stacking direction of the soft-package battery cells in the battery cell stack.

13. The battery pack according to claim 12, characterized in that: The side plate is sandwiched between the battery cell stack and the box body.

14. The battery pack according to claim 2, characterized in that: The battery pack further includes: structural adhesive, and the box body further includes: an upper cover, the upper cover is arranged on the lower shell body to define the installation space therebetween, and the upper cover is directly bonded and fixed to the battery cell stack by the structural adhesive.

15. The battery pack according to claim 6 or 7, characterized in that: The second adhesive layer is also filled between the tabs of adjacent soft-pack batteries.

16. An electric vehicle, characterized in that: A battery pack according to any one of claims 1 to 15.

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