Battery pack and electric vehicle

Abstract

To provide a battery pack that can support a cell stack structure more thoroughly using an adhesive structure, and can prevent mutual interference between different adhesive structures.SOLUTION: A battery pack 300 includes a box body 1, a cell stack 2, an adhesive blocking part, and at least two adhesive structures. Inside the box body, an attachment space is provided. The cell stack includes a plurality of soft pack cells, and the cell stack is disposed inside the attachment space. The adhesive structure is installed in the attachment space, and the adhesive structure is directly connected between the cell stack and the box body. The adhesive blocking part is disposed between the two adhesive structures and separates the two adhesive structures. The battery pack can support the cell stack structure more thoroughly using the adhesive structure, and can prevent mutual interference between the different adhesive structures.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular, to battery packs and electric vehicles incorporating such battery packs.

Background Art

[0002] The operating voltage of a single secondary battery is about 2.5V to 4.5V. In electric vehicles or energy storage systems that require high capacity and high voltage output, usually, a plurality of cells are connected in series and / or in parallel to form a battery module, and then the battery modules are connected in series and / or connected to form a battery pack. Furthermore, it is necessary to use the battery pack as an energy system or an energy storage system that supplies power to an electric vehicle. The number, shape of the battery modules used to form the battery pack, and the number, shape, etc. of the cells used to form the battery modules can be flexibly changed according to actual needs.

[0003] In the field of power batteries used in electric vehicles, in order to improve the full charge duration and charging speed of electric vehicles, it is necessary to further improve the energy density and cooling performance of the battery pack. As a solution to increase the energy density, a CTP (Cell-to-Pack) type battery pack omits the process of connecting cells in series and / or in parallel to form a battery module, and directly integrates the cells into the battery pack, eliminating the structural parts and electrical connectors required for the formation of the battery module, and increasing the space left in the cells themselves.

[0004] Currently, general battery cells are classified into cylindrical cells, prismatic cells, and soft pack cells, etc., due to differences in structure. Although CTP type battery packs using prismatic cells are widely used, soft pack cells are difficult to withstand external impacts and have low assembly performance, so they still face a series of problems during the process of integrating them into CTP type battery packs.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention solves at least one of a plurality of problems faced by soft pack cells integrated into a soft pack CTP type battery pack in the prior art.

Means for Solving the Problems

[0006] A first aspect of the present invention provides a battery pack including a box body, a cell stack, an adhesive blocking portion, and at least two adhesive structures. The box body has an installation space therein. The cell stack includes a plurality of soft pack cells, and the cell stack is disposed in the installation space. The adhesive structure is disposed in the installation space, and the adhesive structure is directly connected between the cell stack and the box body. The adhesive blocking portion is disposed between at least two adhesive structures to isolate the at least two adhesive structures.

[0007] Optionally, the box body includes a lower housing, the lower housing includes a lower housing bottom plate and a beam structure, the cell stack is disposed on the lower housing bottom plate, and the adhesive structure is filled between the cell stack and the lower housing bottom plate and between the cell stack and the beam structure.

[0008] Optionally, one adhesive structure is configured as a first adhesive layer filled and adhered between the bottom of the cell stack and the lower housing bottom plate, and the other adhesive structure is configured as a second adhesive layer filled and adhered between the tab side of the cell stack and the beam structure.

[0009] Optionally, the first adhesive layer includes a thermally conductive structural adhesive, and the second adhesive layer includes a foaming adhesive.

[0010] Optionally, the adhesive blocking portion extends along the stacking direction of the cell stack, and in the length direction of the soft pack cell, the adhesive blocking portion is disposed at both ends of the soft pack cell.

[0011] Optionally, the beam structure includes a first beam structure parallel to the adhesive blocking portion and a second beam structure perpendicular to the adhesive blocking portion, and the adhesive blocking portion extends so as to abut against the second beam structure.

[0012] Optionally, the foaming adhesive is filled between the adhesive blocking portion and the first beam structure.

[0013] Optionally, the adhesive blocking portion includes an elastic material.

[0014] Optionally, the adhesive blocking portion includes a bottom portion that is bonded to the bottom plate of the lower housing, and an upper portion that is pressed against and bonded to the soft pack cell and conforms to the shape of the soft pack cell.

[0015] Optionally, the upper portion includes a plurality of teeth that are spaced apart along the length direction of the adhesive blocking portion, and each tooth accommodates a corresponding soft pack cell.

[0016] Optionally, the maximum height of the teeth is higher than the upper portion of the thermally conductive structural adhesive.

[0017] Optionally, the bottom portion of the adhesive blocking portion is adhered to the bottom plate of the lower housing via a back adhesive.

[0018] Optionally, the battery pack further includes a limiting portion that is disposed on the bottom plate of the lower housing so as to protrude beyond a predetermined height of the bottom plate of the lower housing where the thermally conductive structural adhesive is disposed.

[0019] Optionally, the predetermined height of the limiting portion is lower than or the same as the thickness of the thermally conductive structural adhesive.

[0020] Optionally, the limiting portion is disposed at a position corresponding to an end portion in the length direction of the soft pack cell.

[0021] Optionally, the limiting portion is a frame structure.

[0022] Optionally, the limiting portion and the bottom plate of the lower housing are integrally formed.

[0023] Optionally, the surface of the limiting portion is coated with an insulating coating or the surface of the limiting portion is covered with an insulating film.

[0024] A second aspect of the present invention provides an electric vehicle having the battery pack provided by the first aspect of the present invention.

Advantages of the Invention

[0025] In some technical solutions provided by the present invention, an adhesive structure can be used to more comprehensively support the cell stack structure, and mutual interference between different adhesive structures can be prevented.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

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Figure 20

Embodiments for Carrying Out the Invention

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are included within the protection scope of the present invention.

[0028] <Cell Stack Distribution>

[0029] Figure 1 is a schematic stack distribution diagram of a soft pack type CTP battery pack 100 provided by some embodiments of the present invention.

[0030] Referring to Figure 1, in some embodiments of the present invention, the soft pack type CTP battery pack 100 includes a square box body 1 and a square cell stack 2. The internal space of the box body 1 can accommodate two cell stacks 2 arranged side by side.

[0031] The two cell stacks 2 are a first cell stack 21 and a second cell stack 22. A first output positive electrode 311 and a first output negative electrode 312 are respectively arranged at both ends of the side adjacent to the second cell stack 22 in the first cell stack 21. Correspondingly, a second output positive electrode 321 and a second output negative electrode 322 are respectively arranged at both ends of the side adjacent to the first cell stack 21 in the second cell stack 22. Here, the positions of the first output positive electrode 311 and the second output negative electrode 322 correspond, and the positions of the first output negative electrode 312 and the second output positive electrode 321 correspond, thereby shortening the wiring length and facilitating the electrical series connection between the two cell stacks 2.

[0032] In addition, a third output positive electrode 331 and a third output negative electrode 332 adjacent to each other are further arranged at one end of the first cell stack 21 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 are used as electrodes electrically connected in series within the two cell stacks 2, and the third output positive electrode 331 and the third output negative electrode 332 are used as output electrodes of the entire soft pack type CTP battery pack 100. In some embodiments, the third output positive electrode 331 and the third output negative electrode 332 are electrically connected to a battery pack disconnect unit (BDU), and power is supplied to the entire vehicle through the battery pack disconnect unit.

[0033] The output electrodes provided by the above-described distribution and electrical connection method, i.e., the third output positive electrode 331 and the third output negative electrode 332, are adjacent to each other. In some cases, when it is necessary to separate the output electrodes of the entire soft-pack type CTP battery pack 100 from each other, the first cell stack 21 is rotated 180° with respect to FIG. 1 and arranged in the box body 1, thereby obtaining the assembly structure of the soft-pack type CTP battery pack 200 as shown in FIG. 2.

[0034] Referring to FIG. 2, by rotating 180° and then arranging it in the box body, the third output positive electrode 331 and the third output negative electrode 332 are positioned adjacent to the second cell stack 22. The third output positive electrode 331 and the second output negative electrode 322 are electrically connected via a copper bus bar 36, and the third output negative electrode 332 and the second output positive electrode 321 are electrically connected via another copper bus bar 36. Thereby, the high-voltage electrical connection between the first cell stack 21 and the second cell stack 22 is achieved. The first output positive electrode 311 and the first output negative electrode 312 can be used as the output electrodes of the entire soft-pack type CTP battery pack 200. By using the first cell stack 21 having the above-described electrode distribution and the copper bus bar 36 together, the installation angle of the first cell stack 21 can be flexibly adjusted according to the position requirements of different output electrodes.

[0035] The above example shows the distribution method and electrical connection method of the first cell stack 21 and the second cell stack 22 in some embodiments of the present invention. It can be understood that the above description is merely illustrative and should not be understood as limiting the distribution method and electrical connection method. 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 arrangement position of each output electrode of the cell stack 2 can also be flexibly adjusted according to actual requirements.

[0036] FIG. 3 is an exploded view of the soft-pack type CTP battery pack 100 adopting the stack distribution method corresponding to FIG. 1.

[0037] Referring to FIG. 3, the square box body 1 includes a lower housing 11 and an upper cover 12. The lower housing 11 includes a rectangular lower housing bottom plate 13 and four side beams 14, and the four side beams 14 are respectively fixed perpendicular to the four sides of the rectangular lower housing bottom plate 13. The four side beams 14, the lower housing bottom plate 13 and the upper cover 12 together enclose and define a chamber 16 for accommodating the cell stack 2. In addition to the four side beams 14, the box body 1 further includes a box body central beam 15 disposed at the center in the length direction of the box body 1. The box body central 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 cell stack 21, and the second chamber 162 is used to accommodate the second cell stack 22.

[0038] The bottom of the cell stack 2 and the lower housing bottom plate 13 are directly adhesively fixed via a structural adhesive or a thermally conductive structural adhesive 25 (not shown in FIG. 3. Refer to FIG. 8). In order to stabilize the cell stack 2, enhance the strength and rigidity of the entire battery pack, and protect it from thermal runaway, a foaming adhesive 29 is further filled between the cell stack 2 and the side beam 14 or the box body central beam 15.

[0039] On the upper part of the cell stack 2, a structural adhesive or a thermally conductive structural adhesive or an elastic member (not shown in the figure) is disposed to fill the gap between the cell stack 2 and the upper cover 12. By using the structural adhesive, the thermally conductive structural adhesive 25, the foaming adhesive 29 between the bottom of the cell stack 2 and the lower housing bottom plate 13, and the structural adhesive, the thermally conductive structural adhesive or the elastic member on the upper part of the cell stack 2, a stable buffering support for the cell stack 2 can be formed from all directions around. In some embodiments, the elastic member can be formed by compounding refractory materials such as foams and mica, and a double-sided tape or a hot melt adhesive is disposed between the elastic member and the cell stack 2.

[0040] In some embodiments, a liquid cooling channel (not shown) can be arranged in the lower housing bottom plate 13 and the upper cover 12, and a thermally conductive structural adhesive 25 can be used to quickly transfer the heat dissipated from the cell stack 2 to the liquid cooling channel, thereby enhancing the cooling capacity of the cell stack 2.

[0041] The four side beams 14 include two long side beams 141 and two short side beams 142. An end output pole base 34 is arranged inside the center of the short side beam 142 adjacent to the first cell stack 21, and copper busbars (not shown) connected to the third output positive pole 331 and copper busbars (not shown) connected to the third output negative pole 332 are both arranged on the end output pole base 34.

[0042] A central adapter base 35 is arranged on the box body central beam 15. Copper busbars connected to the first output positive pole 311 and copper busbars connected to the second output negative pole 322 are both arranged on the central adapter base 35, and one ends of the two copper busbars are also both arranged on the central adapter base 35 and are electrically connected to the corresponding copper busbars respectively, thereby achieving the electrical connection between the first cell stack 21 and the second cell stack 22.

[0043] <Cell stack>

[0044] Continuing to refer to FIG. 3, in this embodiment, the cell stack 2 is formed by stacking and adhering a plurality of soft pack cells 23, and the stacking direction is the thickness direction of the soft pack cell 23, that is, the width direction of the box body 1. The length direction of the soft pack cell 23 is parallel to the length direction of the box body 1. The upper and bottom parts of each soft pack cell 23 are completely insulated and protected by insulating tapes (not shown).

[0045] The soft pack cell 23 is a cell that uses a plastic or flexible material such as an aluminum plastic film as a packaging material, and has the advantages of being lightweight, difficult to explode, and having a flexible design. The aluminum-plastic film may be, for example, an aluminum-plastic film including a nylon layer, an aluminum layer, and a PP / CPP layer.

[0046] In some embodiments of the present invention, the size range of the soft pack cell 23 used in the soft pack type CTP battery pack is 300 to 700 mm in length, 100 to 120 mm in width, and 10 to 20 mm in thickness. The thickness of the tab 231 (see FIGS. 14 and 15) is 0.2 to 0.6 mm, and the width is 40 to 80 mm.

[0047] <Side plate>

[0048] How to install the cell stack 2 in the box and apply a temporary clamping force to the cell stack 2 in the initial state are technical problems to be solved during the assembly process of the soft pack type CTP battery pack 100.

[0049] To solve the above problems, referring continuously to FIG. 3, each cell stack 2 of the soft pack type CTP battery pack 100 provided in some embodiments of the present invention has two side plates 24 arranged opposite to each other. The two side plates 24 are respectively arranged inside the long side beams 141 at both ends in the width direction of the box body 1 (that is, both ends in the stacking direction of the cell stack 2), and are adhesively fixed to the main body surfaces of the two soft pack cells 23 at both ends in the stacking direction of the cell stack 2.

[0050] Figure 4 is a schematic structural diagram (top view) of the side plate 24 in some embodiments of the present invention. Referring to Figure 4, the outer surface 243 of the side plate 24 has a concave groove 241 that mates with an external jig. The external jig (not shown) clamps the side plate 24 through the concave groove 241 and applies a temporary clamping force to the cell stack 2 from both ends in the stacking direction of the cell stack 2, compressing the cell stack 2 to a size that is easy to insert into the box body 1. By applying the temporary clamping force, the cycle performance of the cell can be improved. In addition, the concave groove 241 can also facilitate the removal of the jig after the cell stack 2 is placed in the box.

[0051] To make the distribution of the temporary clamping force at each position of the soft pack cell 23 more uniform and avoid local stress concentration, the portion where the inner surface 242 of the side plate 24 contacts the main body surface of the soft pack cell 23 is formed as a flat surface 245. That is, the inner surface 242 of the side plate 24 is configured such that the area of the flat surface 245 is larger than the area of the flat portion of the main body surface of the soft pack cell 23.

[0052] The outer edge of the inner surface 242 of the side plate 24 forms a protruding outer edge limiting portion 244 to limit the relative positional relationship between the side plate 24 and the soft pack cell 23 when the flat surface 245 at the center of the inner surface 242 abuts against the main body surface of the soft pack cell 23.

[0053] The structure of the outer surface 243 of the side plate 24 is as shown in Figure 5. Referring to Figure 5, a second reinforcing rib 247 is arranged in the concave groove 241 arranged on the outer surface 243 of the side plate 24, and a first reinforcing rib 246 is arranged at a position where the concave groove 241 is not arranged. The number of the second reinforcing ribs 247 is more than that of the first reinforcing ribs 246, and the density is also greater than that of the first reinforcing ribs 246, so the strength of the portion that mates with the jig is improved. The height of the second reinforcing rib 247 is lower than that of the first reinforcing rib 246, and the concave groove 241 is formed.

[0054] Optionally, the wall thickness of the side plate 24 is 1.5 - 5 mm, the full width is 5 - 25 mm, and the material of the side plate 24 can be a plastic material such as PA6, PA66, PPE, PBT, etc.

[0055] FIG. 6 is a schematic structural view of the outer surface 243 of the side plate 24 provided in another embodiment of the present invention. FIG. 7 is a schematic view of the cooperation structure between the side plate 24 and the long side beam 141 of the box body 1 in the assembled state. Referring to FIGS. 6 and 7, positioning posts 248 are arranged on the inner wall of the long side beam 141 of the box body 1, and positioning grooves 249 are arranged on the outer surface 243 of the side plate 24. The shapes and sizes of the positioning posts 248 and the positioning grooves 249 match each other, and the positioning posts 248 can be inserted into the positioning grooves 249 to match. The relative movement between the side plate 24 and the long side beam 141 along the length direction of the soft pack cell 23 is restricted, so that the positioning and installation of the cell stack 2 can be conveniently and accurately completed during assembly.

[0056] Note that in other embodiments of the present invention, the concave groove 241 is only one form that matches the external jig. In another embodiment of the present invention, when used in combination with a jig, as long as the jig can stably clamp the cell stack 2, according to the type of the jig, other appropriate forms of jig fitting parts can be arranged on the outer surface 243 of the side plate.

[0057] With the side plate 24 having the above structure, a uniform temporary clamping force can be applied to the cell stack 2 in the initial state, effectively enhancing the grouping ability of the soft pack cells 23, and facilitating the grouping of the soft pack cells 23 and the boxing of the cell stack 2.

[0058] <Thermal Conductive Structural Adhesive 25 - Restriction Portion 26>

[0059] During the assembly process, it is necessary to apply a thermal conductive structural adhesive 25 between the bottom of the cell stack 2 and the bottom plate 13 of the lower housing. The thermal conductive structural adhesive 25 is usually uniformly applied by external pressure to fill the gap. However, due to reasons such as non-uniform pressing force, usually, the thermal conductive structural adhesive 25 in some regions is too thin or too thick, which may affect the heat dissipation efficiency and insulation performance.

[0060] FIG. 8 is a schematic exploded view of a soft pack type CTP battery pack 300 in which a limiting part 26 is arranged in some embodiments. Referring to FIG. 8, in some embodiments of the present invention, in response to the above problems, a limiting part 26 with a predetermined height is provided in a state of being attached to the lower housing bottom plate 13. When the box body 1 is arranged horizontally, the height of the upper part of the limiting part 26 is equal to or slightly lower than the height when the thermally conductive structural adhesive 25 is leveled with an appropriate amount. In this way, the operator or the automatic adhesive application system can determine whether the amount of the applied adhesive is appropriate based on the relative height relationship between the liquid level height of the thermally conductive structural adhesive 25 and the upper part of the limiting part 26. That is, when the added thermally conductive structural adhesive 25 becomes flat and the liquid level is basically on the same plane as the upper part of the limiting part 26, or when the liquid level is slightly higher than the upper part of the limiting part 26, the amount of the added thermally conductive structural adhesive 25 is appropriate; otherwise, it is necessary to adjust the added amount of the thermally conductive structural adhesive 25. By using the limiting part 26, the thickness of the thermally conductive structural adhesive 25 between the cell stack 2 and the box body 1 can be accurately controlled to a certain predetermined thickness value within the range of 0.5 mm to 5 mm.

[0061] In some embodiments of the present invention, the limiting part 26 has a strip shape, that is, the shape of a limiting strip. The limiting part 26 is preferably made of an insulating material such as an elastic body like a foam or silicone rubber, or a plastic such as PP or PPF. In some other embodiments, the limiting part 26 is formed of a high-strength metal material such as an aluminum alloy or stainless steel, and insulation can be achieved by attaching an insulating film to the surface of the metal limiting part 26 or spraying an insulating material.

[0062] In some embodiments, the limiting part 26 may be formed by combining a plurality of limiting strips, or may be formed by integrally forming a plurality of limiting strips. In some other embodiments, the limiting part 26 may be integrally formed with the lower housing bottom plate 13.

[0063] On the one hand, the limiting part 26 can assist in controlling the addition amount of the thermally conductive structural adhesive 25, enhance the uniformity of the thermally conductive structural adhesive 25 at the bottom of the cell stack 2, enhance the heat dissipation capacity of the cell stack 2, and enhance the safety under high-current usage conditions. On the other hand, the limiting part 26 can also separate the cell stack 2 from the lower housing bottom plate 13 so that the bottom of the cell stack 2 does not directly contact the lower housing bottom plate 13 and does not affect the insulation property.

[0064] Referring to FIG. 8, in some embodiments, the limiting part 26 may be an independent member. After fixing the limiting part 26 to the lower housing bottom plate 13, the area between the limiting parts 26 is filled with the thermally conductive structural adhesive 25 having the same height as the limiting part 26 (or slightly higher than the height of the limiting part 26). Then, the cell stack 2 is placed into the box body 1, and by pressing the thermally conductive structural adhesive 25 through the cell stack 2, all the soft pack cells 23 are made to contact the limiting part 26 and the thermally conductive structural adhesive 25 evenly. In this embodiment, the limiting part 26 is formed by combining a plurality of foams or rekon rubbers, the surface of the lower housing bottom plate 13 is flat, and the limiting part 26 is adhered to the surface of the lower housing bottom plate 13.

[0065] FIG. 9 is a top view of the box body 1 with the limiting part 26 attached. Referring to FIG. 9, in the embodiment of FIG. 8, the limiting part 26 is an independently fabricated frame structure including a rectangular limiting part 26 forming an outer frame, a limiting part 26 connecting the diagonal of the rectangle, and a limiting part 26 parallel to the short side beam 142.

[0066] The height of each limiting part 26 is equal and substantially equal to the rated adhesive application height. FIG. 10 is a schematic diagram of the relative positional relationship between the bottom of the soft pack cell 23 and the limiting part 26 at the completion of assembly. Referring to FIGS. 9 and 10, the limiting part 26 extends in the width direction of the box body 1, and its extension range covers the extension range of the cell stack 2 in the width direction of the box body 1. Therefore, by arranging the limiting part 26 in this way, each soft pack cell 23 of the cell stack 2 can be effectively pressed against the limiting part 26.

[0067] FIG. 11 is a schematic structural diagram (exploded view) of a soft-pack type CTP battery pack 400 in some other embodiments of the present invention. Referring to FIG. 11, the limiting part 26 may be integrally formed with the lower housing bottom plate 13. Specifically, the limiting part 26 may be formed by punching on the surface of the lower housing bottom plate 13, or an adhesive application groove may be punched out by punching holes on the surface of the lower housing bottom plate 13. The side wall of the adhesive application groove is higher than the bottom of the adhesive application groove, that is, the side wall of the adhesive application groove corresponds to the limiting part 26.

[0068] FIG. 12 is a schematic diagram of the installation position of the limiting part 26 at the bottom of the box body 1 in the embodiment of FIG. 10. FIG. 13 is a schematic diagram (cross-sectional view) of the relative positional relationship between the soft-pack cell 23, the lower housing bottom plate 13, and the limiting part 26 in the embodiment of FIG. 10. Referring to FIGS. 12 and 13, the limiting part 26 is a limiting part 26 extending along the width direction of the box body 1. The limiting part 26 is integrally formed with the box body 1 and is formed of the same metal material. In order to insulate the limiting part 26, an insulating paint may be sprayed on the surface of the limiting part 26, or it may be covered with an insulating film 261. By integrally forming the limiting part 26, a separate process of positioning and installing the limiting part 26 can be omitted, the process flow is shortened, and the production efficiency is improved.

[0069] <Foaming adhesive>

[0070] In order to enhance the overall strength and rigidity of the soft-pack type CTP battery pack 500 and ensure the structural safety performance of the soft-pack type CTP battery pack 500, in some embodiments of the present invention, a foaming adhesive 29 is further filled between the short side beam 142 and the cell stack 2.

[0071] FIG. 14 is a schematic diagram of the filling position of the foaming adhesive 29 in the soft-pack type CTP battery pack 500 in some embodiments of the present invention. Referring to FIG. 14, the foaming adhesive 29 is filled at both ends in the length direction of the soft-pack cell 23, specifically, between the short side beam 142 and the cell stack 2, and between the box body center beam 15 and the cell stack 2.

[0072] The soft pack cells 23 are stacked vertically in the thickness direction, and the length direction of the soft pack cells 23 is the length direction of the box body 1. Tabs 231 project from both ends of the soft pack cells 23 in the length direction, and the positive tab 231 and the negative tab 231 are respectively located at both ends of the soft pack cells 23 in the length direction. The positive tab 231 and the negative tab 231 of adjacent cells are rounded and bent, and directly overlapped and welded and fixed. Also, in some embodiments, the cell stack 2 may further include a flexible circuit board 28 (see FIG. 3). The main 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.

[0073] FIG. 15 is a schematic diagram of the filling structure of the foaming adhesive 29 between the soft pack cell 23 and the short side beam 142 (partial cross-sectional view along the XY plane of FIG. 14). FIG. 16 is a schematic diagram of the filling height of the foaming adhesive 29 between the soft pack cell 23 and the short side beam 142 (partial cross-sectional view along the XZ plane of FIG. 14). Referring to FIGS. 15 and 16, adjacent tabs 231 are directly overlapped and welded. After welding the tabs 231, the foaming adhesive 29 is injected between the soft pack cell 23, the short side beam 142, and the box body center beam 15. After foaming and curing, the gap between the cell stack 2 and the short side beam 142 and the gap between the cell stack 2 and the box body center beam 15 are filled with the foaming adhesive 29.

[0074] The height of the foaming adhesive 29 obtained after curing is higher than the height of the tab 231. In this way, the foaming adhesive 29 can completely wrap the tab 231 inside the foaming adhesive 29, and between each tab 231, it is electrically insulated by the foaming adhesive 29, thereby effectively preventing the overlapping short circuit between the tabs 231, enhancing the thermal runaway prevention performance, and enhancing the safety and stability.

[0075] In addition to completely immersing the tab 231, the height H1 of the foaming adhesive is preferably not more than the height H3 of the soft pack cell. That is, it is preferable that the height H2 of the tab ≤ the height H1 of the foaming adhesive ≤ the height H3 of the soft pack cell. Since the foaming adhesive 29 can completely immerse the tab 231, when thermal runaway occurs, the high-temperature gas generated inside the soft pack cell 23 is not released from the tab 231, but is discharged from the upper part of the tab 231 of the soft pack cell 23 above the foaming adhesive 29, thereby effectively preventing the expansion of thermal runaway.

[0076] In some embodiments of the present invention, the distance between the tab overlapping surface 232 connecting the tabs 231 to each other and the short side beam 142 or the box body central beam 15 is 3 to 10 mm. An insulating sheet 17 is arranged on the inner surfaces of the short side beam 142 and the box body central beam 15. The insulating sheet 17 has a thickness of 0.1 to 0.5 mm, and the insulating sheet 17 can further ensure the electrical insulation between the tab 231 and the box body 1.

[0077] The density of the cured foaming adhesive 29 is 0.1 to 0.3 g / cm3, the elastic modulus is 10 to 30 MPa, the adhesion performance, shear strength and tensile strength range are 1 to 3 MPa, the elongation at break is ≥ 8%, the compressive elastic modulus is ≥ 30 MPa, and the storage elastic modulus is ≥ 20 MPa. In addition, the material of the foaming adhesive 29 also has insulation properties, and the volume resistivity is ≥ 1×10 15 Ω·cm, and the flame retardancy grade conforms to UL94 V0.

[0078] By the above method, on the one hand, the foaming adhesive 29 can fix the cell stack 2 and increase the rigidity and strength of the soft pack type CTP battery pack 500. On the other hand, the tab 231 can be isolated, such as isolating the tab 231 from the high-temperature gas generated during thermal runaway, or electrically insulating between the tabs 231 or between the tab 231 and the box body 1.

[0079] <Adhesive blocking part>

[0080] In some embodiments of the present invention, in order to prevent the foaming adhesive 29 from penetrating between the cell stack 2 and the thermally conductive structural adhesive 25 and affecting the heat dissipation ability of the cell stack 2 or degrading the mechanical properties of the battery pack, an adhesive blocking portion 27 is further disposed at a position where the foaming adhesive 29 and the thermally conductive structural adhesive 25 may come into contact.

[0081] FIG. 17 is a schematic structural diagram (exploded view) of a soft-pack type CTP battery pack 600 in which the adhesive blocking portion 27 is disposed in some embodiments, and FIG. 18 is a schematic structural diagram after compression of the adhesive blocking portion 27.

[0082] Referring to FIGS. 17 and 18, the extending direction of the adhesive blocking portion 27 is perpendicular to the length direction of the soft-pack cell 23, and both ends in the length direction of the adhesive blocking portion 27 extend so as to abut against the inside of the long-side beam 141, respectively.

[0083] Two adhesive blocking portions 27 are disposed inside the first chamber 161 and the second chamber 162, respectively. The region where the conductive structural adhesive 25 is applied is located between the two adhesive blocking portions 27, and the foaming adhesive 29 is filled between the adhesive blocking portion 27 and the short-side beam 142 and between the adhesive blocking portion 27 and the box body center beam 15.

[0084] The length of the adhesive blocking portion 27 is greater than or equal to the length along the stacking direction of the cell stack 2 and less than the width of the box body 1. The width of the adhesive blocking portion 27 is 1 to 30 mm. The upper portion of the adhesive blocking portion 27 is higher than the upper portion of the thermally conductive structural adhesive 25 so as to limit the application region of the thermally conductive structural adhesive 25 and prevent the overflow of the thermally conductive structural adhesive 25.

[0085] The adhesive blocking portion 27 is preferably composed of an insulating material having a certain degree of elasticity, such as a foam or an elastic material such as silicone rubber, so as to effectively fill the gap, isolate the foaming adhesive 29 and the thermally conductive structural adhesive 25, and prevent the two adhesives from contacting each other.

[0086] The bottom of the adhesive blocking part 27 is flat and can be bonded to the bottom plate 13 of the lower housing through an adhesive disposed on the back surface of the bottom, and can be adhered onto the bottom plate 13 of the lower housing. The upper part can be formed on a flat surface with elasticity. Since there is a certain gap between the soft pack cells 23, when the soft pack cells 23 press the upper plane of the elastic adhesive blocking part 27, a plurality of teeth 271 can be formed at equal intervals along the length direction on the upper part of the adhesive blocking part 27. The tooth pitch between adjacent teeth 271 is equal to the thickness of one or a group of soft pack cells 23. By correspondingly extending each tooth 271 between adjacent soft pack cells 23, the adhesive blocking part 27 can be adhesively fixed to the cell stack 2. As described above, in order to limit the application area of the thermally conductive structural adhesive 25 and prevent the overflow of the thermally conductive structural adhesive 25, the maximum height of each tooth 271 is higher than the upper part of the thermally conductive structural adhesive 25.

[0087] FIG. 19 is a schematic structural diagram (top view) of each member in the box body 1 in the embodiment of FIG. 17. FIG. 20 is a partial enlarged cross-sectional view of the A region in FIG. 19.

[0088] Referring to FIGS. 17, 19 and 20, after the cell stack 2 is attached to a predetermined position, the soft pack cells 23 and the adhesive blocking part 27 are sufficiently crimped, and there is basically no gap between the bottom of the soft pack cells 23 and the adhesive blocking part 27. Thereby, the foaming adhesive 29 and the thermally conductive structural adhesive 25 are effectively isolated, and the contact between the two is avoided.

[0089] By the above method, the adhesive blocking part 27 is in close contact with the bottom of the cell stack 2 and can fill the gap between the soft pack cells 23. Therefore, the foaming adhesive 29 and the thermally conductive structural adhesive 25 are effectively isolated, and the foaming adhesive 29 is prevented from entering between the thermally conductive structural adhesive 25 and the cell stack 2, ensuring the heat dissipation performance of the cell stack 2 and the mechanical performance of the soft pack type CTP battery pack 600.

[0090] In other embodiments of the present invention, as the adhesive blocking method of the adhesive blocking portion 27, filling the gap between adjacent soft pack cells 23, filling the gap between the box body 1 and the cell stack 2, covering the side surface of the soft pack cell 23, etc. can be mentioned, but it is not limited thereto, as long as it can assist in isolating the thermally conductive structural adhesive 25 and the foaming adhesive 29.

[0091] <Assembly process>

[0092] Hereinafter, the assembly process of the soft pack type CTP battery pack provided by some embodiments of the present invention will be introduced.

[0093] First, provide the lower housing 11 of the box body 1. When the lower housing 11 is integrated with the limiting portion 26 or the adhesive blocking portion 27, directly apply the thermally conductive structural adhesive 25 between the lower housing 11 and the limiting portion 26. When the lower housing 11 is not integrated with the limiting portion 26, separately arrange the limiting portion 26 or the adhesive blocking portion 27, and apply the thermally conductive structural adhesive 25 to the area between the added limiting portion 26 or the adhesive blocking portion 27.

[0094] After applying an appropriate amount of the thermally conductive structural adhesive 25, connect the external jig to the concave groove 241 of the side plate 24, and put two cell stacks 2 into the box. Before putting them into the box, the cell stack 2 is compressed to a certain size under the clamping action of the jig, and the total width of the cell stack 2 including the side plate 24 is not more than the width of the chamber 16 inside the box body 1. After putting the cell stack 2 into the box, the jig can be taken out from the concave groove 241 of the side plate 24, and the cell stack 2 slowly rebounds until the first reinforcing rib 246 of the side plate 24 contacts the long side beam 141, and then the rebound stops.

[0095] After the installation of several electrical connectors is completed, a foaming adhesive 29 is injected between the short side beam 142 and the cell stack 2, and between the central beam 15 of the box body and the cell stack 2. After the foaming adhesive 29 hardens and forms, and after other electrical connectors and a battery management system (if any) are installed, a structural adhesive is applied on the cell stack 2, and the upper cover 12 is closed to complete the assembly of the soft pack type CTP battery pack.

[0096] The above-mentioned multiple embodiments provided by the present invention can be combined with each other. In some embodiments, the soft pack type CTP battery pack can also be directly incorporated into the chassis of an electric vehicle, but the embodiments of the present invention do not limit this.

[0097] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Industrial Applicability

[0098] The battery pack of the present invention and the electric vehicle incorporating the battery pack can be applied in the field of power battery technology.

Explanation of Reference Numerals

[0099] 100, 200, 300, 400, 500, 600: Soft pack type CTP battery pack 1: Box body 11: Lower housing 12: Upper cover 13: Bottom plate of the lower housing 14: Side beam 141: Long side beam 142: Short side beam 15: Central beam of the box body 16: Chamber 161: First chamber 162: Second chamber 17: Insulating sheet 2: Cell stack 23: Soft pack cell 231: Tab 232: Tab overlapping surface 24: Side plate 241: Concave groove 242: Inner surface 243: Outer surface 244: Outer edge limiting part 245: Flat surface 246: First reinforcing rib 247: Second reinforcing rib 248: Positioning post 249: Positioning groove 25: Thermally conductive structural adhesive 26: Limiting part 261: Insulating film 27: Adhesive blocking part 271: Tooth 28: Flexible circuit board 29: Foaming adhesive 21: First cell stack 22: Second cell stack 311: First output positive electrode 312: First output negative electrode 321: Second output positive electrode 322: Second output negative electrode 331: Third output positive electrode 332: Third output negative electrode 34: End output electrode base 35: Central adapter base 36: Copper bus bar

Claims

1. A box body having an installation space therein, a cell stack including a plurality of soft pack cells and disposed in the installation space, at least two adhesive structures disposed in the installation space and directly connected between the cell stack and the box body, an adhesive blocking portion disposed between the two adhesive structures and separating the two adhesive structures, A battery pack, characterized by comprising the above.

2. The box body includes a lower housing, the lower housing includes a lower housing bottom plate and a beam structure, the cell stack is disposed on the lower housing bottom plate, and the adhesive structure is filled between the cell stack and the lower housing bottom plate and between the cell stack and the beam structure. The battery pack according to claim 1, characterized by the above.

3. One of the adhesive structures is configured as a first adhesive layer and is filled and adhered between the bottom of the cell stack and the lower housing bottom plate, and the other adhesive structure is configured as a second adhesive layer and is filled and adhered between the tab side of the cell stack and the beam structure. The battery pack according to claim 2, characterized by the above.

4. The first adhesive layer includes a thermally conductive structural adhesive, and the second adhesive layer includes a foaming adhesive. The battery pack according to claim 3, characterized by the above.

5. The adhesive blocking portion extends along the stacking direction of the cell stack, and in the length direction of the soft pack cell, the adhesive blocking portion is disposed at both ends of the soft pack cell. The battery pack according to claim 4, characterized by the above.

6. The beam structure includes a first beam structure parallel to the adhesive blocking portion and a second beam structure perpendicular to the adhesive blocking portion, and the adhesive blocking portion extends so as to abut against the second beam structure. The battery pack according to claim 5, characterized by the above.

7. The foaming adhesive is filled between the adhesive blocking portion and the first beam structure. The battery pack according to claim 6, characterized by the above.

8. The adhesive blocking portion includes an elastic material. The battery pack according to any one of claims 1 to 7, characterized by the above.

9. The adhesive blocking portion includes a bottom bonded to the lower housing bottom plate, an upper portion pressed and bonded to the soft pack cell and conforming to the shape of the soft pack cell. The battery pack according to claim 8, characterized by comprising the above.

10. The upper part includes a plurality of teeth arranged at intervals along the length direction of the adhesive blocking portion, and each of the teeth houses the corresponding soft pack cell. The battery pack according to claim 9, characterized in that.

11. The maximum height of the teeth is higher than the upper part of the thermally conductive structural adhesive. The battery pack according to claim 10, characterized in that.

12. The bottom of the adhesive blocking portion is adhered to the lower housing bottom plate via a back adhesive. The battery pack according to claim 9, characterized in that.

13. The lower housing bottom plate further includes a limiting portion arranged so as to protrude beyond a predetermined height of the lower housing bottom plate where the thermally conductive structural adhesive is arranged. The battery pack according to claim 4, characterized in that.

14. The predetermined height of the limiting portion is lower than or the same as the thickness of the thermally conductive structural adhesive. The battery pack according to claim 13, characterized in that.

15. The limiting portion is arranged at a position corresponding to an end in the length direction of the soft pack cell. The battery pack according to claim 14, characterized in that.

16. The limiting portion is a frame structure. The battery pack according to claim 14 or 15, characterized in that.

17. The limiting portion and the lower housing bottom plate are integrally formed. The battery pack according to claim 14 or 15, characterized in that.

18. The surface of the limiting portion is coated with an insulating coating or the surface of the limiting portion is covered with an insulating film. The battery pack according to claim 17, characterized in that.

19. An electric vehicle, characterized in that it has the battery pack according to any one of claims 1 to 7.

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