Battery pack and electric vehicle

Abstract

To provide a battery pack, and an electric vehicle incorporating the battery pack.SOLUTION: A battery pack 100 includes a box body 1 including a lower part housing bottom plate 13 and a beam structure, a cell stack 2 disposed in the box body and formed by stacking a plurality of soft pack cells 23, a tab extending from the end part of the soft pack cell to the beam structure along a length direction of the soft pack cell, a thermal conductive adhesive disposed between the cell stack and the lower part housing bottom plate, and a foamed adhesive 29 filling the space between the tab and the beam structure. In this configuration, a soft pack CTP type battery pack can be constructed on the basis of the soft pack cell. The excellent protection effect for the cell stack formed by stacking the soft pack cells is exhibited, the assembling is easy, and the stability of the entire battery pack is more excellent.SELECTED DRAWING: Figure 3

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 constitute the battery pack, the number, shape, etc. of the cells used to constitute the battery module 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 battery packs. As a solution to increase the energy density, the CTP (Cell-to-Pack) type battery pack omits the process of forming cells into battery modules and directly integrates the cells into the battery pack, eliminating the structural parts and electrical connectors required for the formation of battery modules, and increasing the space left in the cells themselves.

[0004] Currently, general battery cells are classified into cylindrical cells, prismatic cells, soft-pack cells, etc. according to structural differences. 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 into CTP-type battery packs. In the prior art, it is troublesome to directly attach a soft-packed cell stack to a battery pack, and it is not easy to effectively protect the cell stack. As a result, the overall stability of the battery pack decreases.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above-mentioned drawbacks 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.

Means for Solving the Problems

[0006] To achieve the above object and other related objects, the present invention provides a battery pack including a box body having an installation space inside; a cell stack including a plurality of soft-pack cells arranged in layers and disposed in the installation space; and at least two types of adhesive structures disposed in the installation space and directly connected between the cell stack and the box body.

[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, the adhesive structure 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 another 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.

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

[0010] Optionally, the second adhesive layer includes a foaming adhesive.

[0011] Optionally, the beam structure includes side beams, a part of the tab of each soft pack cell faces the side beams, and the second adhesive layer is disposed between the tab and the side beams.

[0012] Optionally, the beam structure further includes one or more box body central beams, another part of the tab of the soft pack cell faces the box body central beams, and the second adhesive layer is further disposed between the tab and the box body central beams.

[0013] Optionally, one or more of the box body central beams divide the lower housing bottom plate into a plurality of regions, there are a plurality of cell stacks, and each cell stack is disposed in one of the regions.

[0014] Optionally, the height H1 of the foaming adhesive, the height H2 of the tab, and the body height H3 of the soft pack cell satisfy the mathematical formula H2 ≤ H1 ≤ H3.

[0015] Optionally, the second adhesive layer wraps the tab of the soft pack cell.

[0016] Optionally, the density of the foaming adhesive 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.

[0017] Optionally, the battery pack further includes side plates, and the side plates are disposed on both sides of the cell stack along the stacking direction of the soft pack cells in the cell stack.

[0018] Optionally, the side plates are sandwiched between the cell stack and the box body.

[0019] Optionally, the battery pack further includes a structural adhesive, the box body further includes an upper cover, the upper cover covers the lower housing, defines the mounting space therebetween, and the upper cover and the cell stack are directly adhesively fixed via the structural adhesive.

[0020] Optionally, the second adhesive layer is further filled between the tabs of the adjacent soft pack cells.

Advantages of the Invention

[0021] The technical solution provided by the present invention constructs a soft pack type CTP battery pack based on soft pack cells, has an excellent protective effect on the cell stack formed by laminating soft pack cells, and is easy to assemble.

[0022] The 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

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Embodiments for Carrying Out the Invention

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative efforts based on the embodiments of the present invention are included within the protection scope of the present invention.

[0025] As shown in FIGS. 1 to 20, according to some embodiments of the present invention, the box body 1 has an installation space (cavity 16) therein, and the cell stack 2 includes a plurality of stacked soft pack cells 23. The cell stack 2 is arranged in the installation space, has at least two types of adhesion structures, the adhesion structures are arranged in the installation space, and the adhesion structures are directly connected between the cell stack 2 and the box body 1 to ensure a stable arrangement of the cell stack 2 in the installation space.

[0026] Furthermore, the box body 1 includes a lower housing 11, the lower housing 11 includes a lower housing bottom plate 13 and a beam structure, the cell stack 2 is arranged on the lower housing bottom plate 13, and the adhesion structures are filled between the cell stack 2 and the lower housing bottom plate 13 and between the cell stack 2 and the beam structure.

[0027] Here, the adhesion structure is configured as a first adhesive layer and is filled and adhered between the bottom of the cell stack 2 and the lower housing bottom plate 13. Another adhesion structure is configured as a second adhesive layer and is filled and adhered between the tab side of the cell stack 2 and the beam structure.

[0028] Specifically, the first adhesive layer includes a thermally conductive structural adhesive, and the second adhesive layer includes a foaming adhesive.

[0029] Furthermore, the beam structure includes side beams 14. A part of the tab 231 of each soft pack cell 23 faces the side beam 14, and the second adhesive layer is arranged between the tab 231 and the side beam 14. The beam structure further includes one or more box body central beams 15. Another part of the tab 231 of the soft pack cell 23 faces the box body central beam 15, and the second adhesive layer is further arranged between the tab 231 and the box body central beam 15. The second adhesive layer is further filled between the tabs 231 of adjacent soft pack cells 23.

[0030] Here, one or more box body central beams 15 divide the lower box body bottom plate 13 into a plurality of regions, there are a plurality of cell stacks 2, and each cell stack 2 is arranged in one of the regions.

[0031] Preferably, the second adhesive layer wraps the tab 231 of the soft pack cell 23 to realize insulation protection of the tab 231.

[0032] Furthermore, the battery pack further includes side plates 24, and the side plates 24 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. Here, the side plates 24 are sandwiched between the cell stack 2 and the box body 1.

[0033] The battery pack further includes a structural adhesive, the box body 1 further includes an upper cover 12, the upper cover 12 covers the lower box body 11, defines an installation space therebetween, and the upper cover 12 and the cell stack 2 are directly adhesively fixed via the structural adhesive.

[0034] <Cell stack distribution>

[0035] FIG. 1 is a schematic diagram of the stack distribution of a soft pack type CTP battery pack 100 provided according to some embodiments of the present invention.

[0036] Referring to FIG. 1, in an embodiment of the present invention, the soft pack type CTP battery pack 100 includes a rectangular box body 1 and a rectangular cell stack 2. The internal space of the box body 1 can arrange two cell stacks 2 side by side.

[0037] The two cell stacks 2 are the first cell stack 21 and the 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 of the first cell stack 21 adjacent to the second cell stack 22. Correspondingly, the second cell stack 22 has a second output positive electrode 321 and a second output negative electrode 322 respectively arranged at both ends of the side adjacent to the first cell stack 21. 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.

[0038] In addition, the first cell stack 21 further has a third output positive electrode 331 and a third output negative electrode 332 adjacent to each other arranged 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 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 supply power to the entire vehicle through the battery pack disconnect unit.

[0039] The output electrodes provided by the above-described distribution and electrical connection method, that is, 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 1, thereby obtaining the assembly structure of the soft-pack type CTP battery pack 200 as shown in FIG. 2.

[0040] Referring to FIG. 2, by rotating 180° and then arranging it inside the box, 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.

[0041] 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 construed as limiting the distribution method and electrical connection method. In another embodiment 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.

[0042] FIG. 3 is an exploded view of a soft-pack type CTP battery pack 100 adopting the stack distribution method corresponding to FIG. 1.

[0043] Referring to FIG. 3, the rectangular 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. The four side beams 14 are respectively fixed perpendicularly 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 cavity (mounting space) 16 for accommodating the cell stack 2. 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 in addition to the four side beams 14. The box body central beam 15 divides the cavity 16 into a first cavity 161 and a second cavity 162. The first cavity 161 is used to accommodate the first cell stack 21, and the second cavity 162 is used to accommodate the second cell stack 22.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 the copper bus bars (not shown) connected to the third output positive electrode 331 and the copper bus bars (not shown) connected to the third output negative electrode 332 are both arranged on the end output pole base 34.

[0048] A central adapter base 35 is arranged on the box body central beam 15. The copper bus bars connected to the first output positive electrode 311 and the copper bus bars connected to the second output negative electrode 322 are both arranged on the central adapter base 35, and one ends of the two copper bus bars are also both arranged on the central adapter base 35 and are electrically connected to the corresponding copper bus bars respectively, thereby achieving the electrical connection between the first cell stack 21 and the second cell stack 22.

[0049] <Cell stack>

[0050] 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 lower parts of each soft pack cell 23 are completely insulated and protected by insulating tapes (not shown).

[0051] 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.

[0052] In one embodiment 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.

[0053] <Side plate>

[0054] How to install the cell stack 2 in the box and how to 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.

[0055] To solve the above problems, referring to FIG. 3, each cell stack 2 of the soft pack type CTP battery pack 100 provided by 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.

[0056] Figure 4 is a schematic structural view (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.

[0057] To more evenly disperse the temporary clamping force to each position of the soft pack cell 23 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 area of the inner surface 242 of the side plate 24 formed as the flat surface 245 is larger than the area of the flat portion of the main body surface of the soft pack cell 23.

[0058] The outer edge of the inner surface 242 of the side plate 24 protrudes to form an outer edge limiting portion 244 in order to limit the relative positional relationship between the limiting side plate 24 and the soft pack cell 23 when the flat surface 245 at the center of the inner surface 242 and the main body surface of the soft pack cell 23 are in contact with each other.

[0059] 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. Since the number of the second reinforcing ribs 247 is more than that of the first reinforcing ribs 246 and the density is greater than that of the first reinforcing ribs 246, the strength of the portion mating 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.

[0060] 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 may be a plastic material such as PA6, PA66, PPE, PBT, etc.

[0061] 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 mounted 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.

[0062] In addition, in other embodiments of the present invention, the concave groove 241 is only one form that matches an 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.

[0063] 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.

[0064] <Thermal Conductive Structural Adhesive 25 - Restriction Portion 26>

[0065] 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 areas is too thin or too thick, which may affect the heat dissipation efficiency and insulation performance.

[0066] FIG. 8 is a schematic explosion 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 one embodiment of the present invention, to address 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 an appropriate amount of the thermally conductive structural adhesive 25 is leveled. In this way, an operator or an automatic adhesive application system can determine whether the amount of the adhesive to be applied 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.

[0067] In one embodiment 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 pasting an insulating film on the surface of the metal limiting part 26 or spraying an insulating material.

[0068] 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.

[0069] 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 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.

[0070] 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.

[0071] 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.

[0072] 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 the extension range thereof 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.

[0073] FIG. 11 is a schematic exploded view of the structure of a soft-pack type CTP battery pack 400 in some other embodiments of the present invention. Referring to FIG. 11, the restricting portion 26 may be integrally formed with the lower housing bottom plate 13. Specifically, the restricting portion 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 restricting portion 26.

[0074] FIG. 12 is a schematic view of the installation position of the restricting portion 26 at the bottom of the box body 1 in the embodiment of FIG. 10. FIG. 13 is a schematic view of the relative positional relationship (cross-sectional view) between the soft-pack cell 23, the lower housing bottom plate 13, and the restricting portion 26 in the embodiment of FIG. 10. Referring to FIGS. 12 and 13, the restricting portion 26 is a restricting portion 26 extending along the width direction of the box body 1. The restricting portion 26 is integrally formed with the box body 1 and is formed of the same metal material. In order to insulate the restricting portion 26, an insulating paint may be sprayed on the surface of the restricting portion 26, or it may be covered with an insulating film 261. By integrally forming the restricting portion 26, a separate process of positioning and attaching the restricting portion 26 can be omitted, the process flow is shortened, and the production efficiency is improved.

[0075] <Foaming adhesive>

[0076] 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.

[0077] FIG. 14 is a schematic view 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 tab side of the cell stack 2, and between the box body center beam 15 and the tab side of the cell stack 2.

[0078] The soft pack cells 23 are stacked vertically in the thickness direction, and the length direction of the soft pack cells 23 is the same as 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 to be 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 in parallel with the tab 231, and the sampling piece (not shown) of the flexible circuit board 28 is welded to the tab 231.

[0079] FIG. 15 is a schematic view 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 view 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, the adjacent tabs 231 are directly overlapped and welded. After welding the tabs 231, the foaming adhesive 29 is injected between the tab side of the soft pack cell 23, the short side beam 142, and the box body central beam 15. After foaming and curing, the gaps between the cell stack 2 and the short side beam 142 and between the cell stack 2 and the box body central beam 15 are filled with the foaming adhesive 29.

[0080] 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 the spaces between the tabs 231 are 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 improving the safety and stability.

[0081] The height H1 of the foaming adhesive, the height H2 of the tab 231, and the body height H3 of the soft pack cell 23 satisfy the mathematical formula H2 ≤ H1 ≤ H3. That is, 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 discharged 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.

[0082] In one embodiment 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 disposed 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.

[0083] The density of the foaming adhesive 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. That is, the density after curing of the foaming adhesive 29 is 0.1 to 0.3 g / cm3, the elastic modulus is 10 to 30 MPa, the ranges of the shear strength and the tensile strength are 1 to 3 MPa, the elongation at break point 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.

[0084] 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 CTP type 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.

[0085] <Adhesive blocking part>

[0086] In order to prevent the foaming adhesive 29 from entering 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, in some embodiments of the present invention, an adhesive blocking part 27 is further disposed at a position where the foaming adhesive 29 and the thermally conductive structural adhesive 25 may come into contact.

[0087] FIG. 17 is a schematic structural diagram (exploded view) of a soft-pack type CTP battery pack 600 in which the adhesive blocking part 27 is disposed in some embodiments, and FIG. 18 is a schematic structural diagram after compression of the adhesive blocking part 27.

[0088] Referring to FIGS. 17 and 18, the stretching direction of the adhesive blocking part 27 is perpendicular to the length direction of the soft-pack cell 23, and both ends in the length direction of the adhesive blocking part 27 extend so as to abut against the inside of the long-side beam 141 respectively.

[0089] Two adhesive blocking parts 27 are disposed inside the first cavity 161 and the second cavity 162 respectively. The region where the conductive structural adhesive 25 is applied is located between the two adhesive blocking parts 27, and the foaming adhesive 29 is filled between the adhesive blocking part 27 and the short-side beam 142 and between the adhesive blocking part 27 and the box body central beam 15.

[0090] The length of the adhesive blocking part 27 is not less than 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 part 27 is 1 to 30 mm. The upper part of the adhesive blocking part 27 restricts the application region of the thermally conductive structural adhesive 25 and is higher than the upper part of the thermally conductive structural adhesive 25 so as to prevent the overflow of the thermally conductive structural adhesive 25.

[0091] Next, the adhesive blocking portion 27 is preferably made of an insulating material having a certain degree of elasticity, such as a foam or an elastic material such as silicone rubber, in order to effectively fill the gap, isolate the foaming adhesive 29 from the thermally conductive structural adhesive 25, and prevent the two adhesives from contacting each other.

[0092] The bottom of the adhesive blocking portion 27 is flat and bonded to the lower housing bottom plate 13. The upper portion can be formed on a flat surface having 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 portion 27, a plurality of teeth 271 arranged at equal intervals along the length direction can be formed on the upper portion of the adhesive blocking portion 27. The tooth interval between adjacent teeth 271 is equal to the thickness of one or a group of soft pack cells 23. By extending each tooth 271 correspondingly between adjacent soft pack cells 23, the adhesive blocking portion 27 can be adhesively fixed to the cell stack 2.

[0093] FIG. 19 is a schematic structural view (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.

[0094] Referring to FIGS. 17, 19, and 20, after the cell stack 2 is attached to a predetermined position, the soft pack cell 23 and the adhesive blocking portion 27 are sufficiently crimped, and there is basically no gap between the bottom of the soft pack cell 23 and the adhesive blocking portion 27. Thereby, the foaming adhesive 29 and the thermally conductive structural adhesive 25 are effectively isolated, and contact between the two is avoided.

[0095] By the above method, the adhesive blocking portion 27 can be in close contact with the bottom of the cell stack 2 and fill the gap between the soft pack cells 23. Therefore, the foaming adhesive 29 and the thermally conductive structural adhesive 25 are effectively isolated, preventing the foaming adhesive 29 from penetrating between the thermally conductive structural adhesive 25 and the cell stack 2, and ensuring the heat dissipation performance of the cell stack 2 and the mechanical performance of the soft pack type CTP battery pack 600.

[0096] In another embodiment 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, and any method that can assist in isolating the thermally conductive structural adhesive 25 and the foaming adhesive 29 is acceptable.

[0097] <Assembly process>

[0098] Hereinafter, the assembly process of the soft pack type CTP battery pack provided by some embodiments of the present invention will be introduced.

[0099] First, the lower housing 11 of the box body 1 is provided. When the lower housing 11 is integrated with the limiting portion 26 or the adhesive blocking portion 27, the thermally conductive structural adhesive 25 is directly applied between the lower housing 11 and the limiting portion 26. When the lower housing 11 is not integrated with the limiting portion 26, separately, the limiting portion 26 or the adhesive blocking portion 27 is arranged, and the thermally conductive structural adhesive 25 is applied to the area between the added limiting portion 26 or the adhesive blocking portion 27.

[0100] After applying an appropriate amount of the thermally conductive structural adhesive 25, an external jig is connected to the concave groove 241 of the side plate 24, and two cell stacks 2 are placed into the box. Before being placed 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 cavity 16 inside the box body 1. After the cell stack 2 is placed 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.

[0101] After the installation of some electrical connectors is completed, a foaming adhesive 29 is injected between the short side beam 142 and the cell stack 2, and between the box body central beam 15 and the cell stack 2. After the foaming adhesive 29 hardens and forms, and after other electrical connectors and the 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.

[0102] The above 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.

[0103] The above are only preferred embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Industrial Applicability

[0104] 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

[0105] 100, 200, 300, 400, 500, 600: Soft pack type CTP battery pack 1: Box body 11: Lower housing 12: Upper cover 13: Lower housing bottom plate 14: Side beam 141: Long side beam 142: Short side beam 15: Box body central beam 16: Cavity 161: First cavity 162: Second cavity 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 pillar 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 inside, including a plurality of soft pack cells arranged in a stacked manner, and a cell stack arranged in the installation space, at least two types of adhesive structures arranged in the installation space and directly connected between the cell stack and the box body, characterized in that it includes a battery pack.

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 arranged 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, characterized in that it is the battery pack according to Claim 1.

3. One of the adhesive structures 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 of the adhesive structures is configured as a second adhesive layer, filled and adhered between the tab side of the cell stack and the beam structure, characterized in that it is the battery pack according to Claim 2.

4. The first adhesive layer includes a thermally conductive structural adhesive, characterized in that it is the battery pack according to Claim 3.

5. The second adhesive layer includes a foaming adhesive, characterized in that it is the battery pack according to Claim 3.

6. The beam structure includes side beams, a part of the tab of each soft pack cell faces the side beam, and the second adhesive layer is arranged between the tab and the side beam, characterized in that it is the battery pack according to Claim 3.

7. The beam structure further includes one or more box body central beams, another part of the tab of the soft pack cell faces the box body central beam, and the second adhesive layer is further arranged between the tab and the box body central beam, characterized in that it is the battery pack according to Claim 6.

8. One or more of the box body central beams divide the lower housing bottom plate into a plurality of regions, there are a plurality of the cell stacks, and each cell stack is arranged in one of the regions, characterized in that it is the battery pack according to Claim 7.

9. The height H1 of the foaming adhesive, the height H2 of the tab, and the body height H3 of the soft pack cell satisfy the mathematical formula H2 ≤ H1 ≤ H3, characterized in that it is the battery pack according to Claim 5.

10. The second adhesive layer wraps the tab of the soft pack cell, characterized in that it is the battery pack according to Claim 9.

11. The density of the foaming adhesive is a, where 0.2 ≤ a ≤ 0.3 g / cm3, the elastic modulus is b, where 10 ≤ b ≤ 30 MPa, the shear strength is c, where 1 ≤ c ≤ 3 MPa, and the tensile strength is d, where 1 ≤ d ≤ 3 MPa. The battery pack according to claim 5, characterized in that.

12. Further comprising side plates, the side plates being disposed on both sides of the cell stack along the stacking direction of the soft pack cells in the cell stack. The battery pack according to claim 1, characterized in that.

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

14. The battery pack further comprises a structural adhesive, the box body further comprises an upper cover, the upper cover covers the lower housing, defines the mounting space therebetween, and the upper cover and the cell stack are directly adhesively fixed via the structural adhesive. The battery pack according to claim 2, characterized in that.

15. The second adhesive layer is further filled between the tabs of the adjacent soft pack cells. The battery pack according to any one of claims 1, 6 or 7, characterized in that.

16. An electric vehicle, characterized by having the battery pack according to any one of claims 1 to 14.

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