Heating film and battery pack

Abstract

The present application discloses a heating film and a battery pack. The heating film is used for heating a plurality of battery cells arranged in sequence. The heating film comprises a plurality of heating areas spaced apart from each other and a folding connecting area located between every two adjacent heating areas among the plurality of heating areas; the edge of each folding connecting area adjacent to each of two adjacent heating areas is a folding edge; the heating film can be folded along the folding edges; through holes are formed in the heating film; the folding edges are located at the edges of the through holes or pass through the through holes. According to the technical solution of the present application, the stress of the heating film at the folding edges can be reduced, thereby facilitating folding and assembling and allowing for continuous bending operation on the heating film; moreover, arching of the heating area under the action of stress is avoided, and the attaching effect between the heating area and the surfaces of the battery cells is ensured.

Description

Heating film and battery pack Technical Field

[0001] The present application relates to the field of battery technology, and more specifically to a heating film, and also to a battery pack including the heating film.

[0002] Background of the Invention

[0003] With the development of society, electronic terminal products such as drones, vacuum cleaners, power tools, and medical equipment need to be used and operated in some extremely cold environments. However, during the storage and use of lithium-ion batteries, temperature has a significant impact on the performance and life of the battery. In low-temperature environments: 1. The battery's discharge capacity is poor; the diffusion rate of lithium ions in the graphite negative electrode will be slower, and lithium precipitation is more likely to occur. As the temperature drops, the reaction rate of the electrode also decreases. Assuming the battery voltage remains constant, the discharge current decreases, and the battery's power output also decreases. 2. Low-temperature charging is not saturated. At low temperatures, the viscosity of the electrolyte decreases, the conductivity decreases, and the activity of the active material also decreases. This will increase the concentration difference of the electrolyte, enhance polarization, and cause charging to terminate prematurely, which also leads to a decrease in battery capacity. 3. Safety hazards: Affected by low temperatures, the speed of lithium embedding in graphite decreases, and metallic lithium is easily precipitated on the surface of the negative electrode. If the battery is not left for long enough after charging before being put into use, the metallic lithium cannot be completely re-embedded in the graphite. Some metallic lithium continues to exist on the surface of the negative electrode, and it is very likely to form lithium dendrites. When the dendrites grow to a sufficient size, they may pierce the diaphragm, causing direct connection between the positive and negative electrodes and forming an internal short circuit.

[0004] Therefore, battery insulation measures are needed. Currently, a common heating method on the market is to use an internal heating film, which generates heat and provides insulation to the battery cell modules. However, due to the irregular structure of the battery, stress is generated at the bent corners of the heating film. This stress arches the heating film, preventing it from properly bonding to each battery cell and effectively transferring heat to the cells.

[0005] Summary of the Invention

[0006] In view of this, the present application provides a heating film and also provides a battery pack including the above-mentioned heating film, which solves the problem of stress generated at the bent corners of the heating film and the generated stress arching the heating film.

[0007] In order to achieve the above objectives, this application provides the following technical solutions:

[0008] A heating film is used to heat a plurality of battery cells arranged in sequence; the heating film comprises a plurality of heating zones arranged at intervals and a folded connection zone located between two adjacent heating zones among the plurality of heating zones;

[0009] The edge of the folded connection area adjacent to each of the two adjacent heating areas is a folded edge; the heating film can be folded along the folded edge;

[0010] Wherein, a through hole is opened on the heating film; the folding edge is located at the edge of the through hole or passes through the through hole.

[0011] Optionally, in the above heating film, a plurality of through holes are provided along the extending direction of the folded edge;

[0012] and / or,

[0013] Along the extending direction of the folding edge, the ratio of the total length of the through hole to the length of the folding edge is 0.5-0.8.

[0014] Optionally, in the above-mentioned heating film, corners of the through hole are chamfered.

[0015] Optionally, in the above-mentioned heating film, the heating film includes:

[0016] Two protective layers arranged in a stacked pattern;

[0017] A heating core is disposed between the two protective layers, and an electrical connection end of the heating core is located in the folded connection area;

[0018] An electrical connector is electrically connected to the electrical connection end.

[0019] Optionally, in the above-mentioned heating film, the electrical connector is connected to a temperature switch;

[0020] When the temperature is higher than the first set value, the temperature switch is disconnected and the heating film stops heating; when the temperature is lower than the second set value, the temperature switch is closed and the heating film heats.

[0021] Optionally, in the above heating film, the heating core is a heating resistance wire; and / or,

[0022] The electrical connector is a connecting wire; and / or,

[0023] An insulating protective layer is provided at the connection between the electrical connector and the electrical connection end.

[0024] Optionally, in the above-mentioned heating film, positioning holes are opened on the heating film, so that when the heating film and the plurality of battery cells are assembled, the positioning holes are positioned with positioning points of an assembly jig.

[0025] Optionally, in the above heating film, adhesive members are provided on both the front and back sides of the heating zone.

[0026] Optionally, in the above-mentioned heating film, along the length direction of each of the plurality of battery cells, the heating area includes a first end and a second end that are opposite to each other;

[0027] Adhesive members are arranged at intervals near the first end and near the second end of the heating zone.

[0028] Optionally, in the above-mentioned heating film, the length dimension of the heating zone is not greater than the length dimension of each battery cell in the plurality of battery cells; the width dimension of the heating zone is not greater than the width dimension of the battery cell;

[0029] and / or,

[0030] The length of the folding connection area is not greater than the length of each of the multiple battery cells; in the folded heating film, the folding connection area and two adjacent heating areas form a folding space; the width of the folding connection area is not less than the sum of the thicknesses of all the battery cells that can be accommodated in the folding space;

[0031] and / or,

[0032] The thickness of the heating film is 0.13mm-0.5mm.

[0033] Optionally, in the above-mentioned heating film, the heating power of the heating zones at both ends of the heating film is greater than the heating power of the heating zone at the middle area of ​​the heating film.

[0034] Optionally, in the above-mentioned heating film, the through hole is opened in the folding connection area, and along the spacing arrangement direction of multiple heating zones, the width of the through hole is the same as the width of the folding connection area; or, the opening area of ​​the through hole exceeds the folding connection area, and the two edges of the through hole fall into two adjacent heating zones respectively.

[0035] A battery pack comprising a battery cell module and the heating film described above;

[0036] The battery cell module includes a plurality of battery cell monomers arranged in sequence;

[0037] Along the arrangement direction of the plurality of battery cells, the heating film sequentially forms a plurality of folded spaces; the plurality of battery cells are arranged in the plurality of folded spaces.

[0038] Optionally, in the above battery pack, the battery pack further comprises a tab welding plate; the tab welding plate is located above the battery cell module; and a guide hole is provided on the tab welding plate;

[0039] The heating film includes an electrical connector; the electrical connector passes through the guide hole.

[0040] Optionally, in the above battery pack, the battery pack further includes a control circuit board;

[0041] The electrical connector in the heating film is electrically connected to the control circuit board.

[0042] In the heating film and battery pack provided by the present application, a through hole is provided on the folding connection area; when the heating film is folded and arranged in sequence along the folding edges adjacent to the heating area of ​​the folding connection area, since a through hole is provided between the two folding edges of the folding connection area, the material consumption of the heating film at the folding edge is effectively reduced, and the size of the material folded along the folding edge is reduced, thereby effectively reducing the stress of the heating film at the folding edge (the folding edge is the bending corner of the heating film), facilitating folding and assembly, and realizing the continuous bending operation of the heating film; and avoiding the heating area from being arched under the action of the stress, ensuring the fitting effect between the heating area and the surface of the battery cell, and being able to transfer heat to the battery cell well; at the same time, the through hole provided reduces the self-gravity of the heating film, and ensures the energy density of the battery pack.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0045] FIG1 is a schematic structural diagram of the heating film of the present application.

[0046] FIG2 is a folded heating film of the present application.

[0047] FIG3 is a schematic structural diagram of the heating core inside the heating film of the present application.

[0048] FIG4 is a schematic structural diagram of an adhesive member provided on the front side of the heating film of the present application.

[0049] FIG5 is a schematic structural diagram of an adhesive member provided on the reverse side of the heating film of the present application.

[0050] FIG6 is a schematic diagram of the first step of assembling the heating film and the battery cell of the present application.

[0051] FIG7 is a second schematic diagram of the assembly steps of the heating film and the battery cell of the present application.

[0052] FIG8 is a third schematic diagram of the assembly steps of the heating film and the battery cell of the present application.

[0053] FIG9 is a fourth schematic diagram of the assembly steps of the heating film and the battery cell of the present application.

[0054] FIG10 is a side view of a semi-finished battery core unit of the present application.

[0055] FIG11 is a front view of the semi-finished battery core unit of the present application.

[0056] FIG12 is a cross-sectional view taken along line VV in FIG11 of the present application.

[0057] FIG13 is a schematic diagram of the assembly of the semi-finished battery core unit, the tab welding plate, and the tab isolation foam of the present application.

[0058] FIG14 is a schematic diagram of the assembly structure and the control circuit board, wires, and connector terminals in FIG13 of the present application.

[0059] FIG15 is a schematic diagram of the assembly structure and auxiliary foam in FIG14 of the present application.

[0060] FIG16 is a schematic structural diagram of the battery core unit of the present application.

[0061] FIG17 is a schematic diagram of an exploded view of the core unit of the battery cell of the present application.

[0062] FIG18 is a schematic diagram of the assembly of the battery core unit, the upper shell, and the lower shell of the present application.

[0063] FIG19 is a front view of a battery cell of the present application.

[0064] FIG20 is a side view of a battery cell of the present application.

[0065] Figures 1 to 20: 1. Heating film; 2. Cell module; 3. Tab welding plate; 4. Control circuit board; 5. Tab isolation foam; 6. Insulation sheet; 7. Positive conductor; 8. Negative conductor; 9. Signal cable; 10. Connector terminal; 11. Control circuit board screw; 12. Connector terminal screw; 13. Front auxiliary foam; 14. Rear auxiliary foam; 15. Left auxiliary foam; 16. Right auxiliary foam; 17. Bottom auxiliary foam; 18. Upper shell; 19. Lower shell; 20. Battery core unit semi-finished product; 21. Battery core unit; 101. Heating area; 102. Folding connection area; 103. Protective layer; 104. Heating core; 105. Electrical connector; 106. Temperature switch; 107. Adhesive; 201. Cell; 202. Cell isolation foam; 301. Guide hole; 1011, first heating zone; 1012, second heating zone; 1013, third heating zone; 1014, fourth heating zone; 1015, fifth heating zone; 1016, sixth heating zone; 1017, positioning hole; 1021, first folding connection zone; 1022, second folding connection zone; 1023, third folding connection zone; 1024, fourth folding connection zone; 1025, fifth folding connection zone; 1026, through hole; 1027, folded edge; 1041, electrical connection terminal; 2011, the first battery cell; 2012, the second battery cell; 2013, the third battery cell; 2014, the fourth battery cell; 2015, the fifth battery cell; 2016, the sixth battery cell; 2017, the seventh battery cell; 2018, the eighth battery cell; 2019, the ninth battery cell; 20110, the tenth battery cell; 20111, the eleventh battery cell; 20112, the twelfth battery cell.

[0066] Modes for Carrying Out the Invention

[0067] The present application provides a heating film and also provides a battery pack including the heating film.

[0068] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0069] As shown in Figure 1-20, a heating film is used to heat a plurality of battery cells 201 arranged in sequence. The heating film 1 includes a plurality of heating zones 101 arranged at intervals and a folding connection zone 102 located between two adjacent heating zones 101. The edge of the folding connection zone 102 adjacent to the heating zone 101 is a folding edge 1027; the heating film 1 can be folded along the folding edge 1027. Please refer to Figure 2. The plurality of heating zones 101 in the folded heating film 1 are arranged in sequence along the arrangement direction of the battery cells 201, and the folding connection zone 102 is parallel to the arrangement direction of the battery cells 201. A through hole 1026 is opened on the heating film; the folding edge is located at the edge of the through hole 1026 or passes through the through hole 1026.

[0070] It should be noted that the folding edge 1027 is located at the edge of the through hole 1026 or passes through the through hole 1026, which means that, when the heating film is unfolded, the through hole 1026 happens to be opened in the folding connection area 102, and along the spacing direction of the multiple heating zones 101, the width of the through hole 1026 happens to be the same as the width of the folding connection area 102; or, when the heating film is unfolded, the opening area of ​​the through hole 1026 exceeds the folding connection area 102, and the two edges of the through hole 1026 happen to fall into the two heating zones 101 adjacent to the folding connection area 102, that is, along the spacing direction of the multiple heating zones 101, the width of the through hole 1026 is greater than the width of the folding connection area 102.

[0071] It should be further explained that, when the heating film is in an unfolded state, the spacing arrangement direction of the plurality of heating zones 101 is as shown in the direction of the arrows in FIG. 4 .

[0072] In the folded heating film 1, the folded connection area 102 and the two adjacent heating areas 101 enclose a folded space; the heating film 1 forms multiple folded spaces arranged in an S-shaped direction, as shown in Figures 2 and 17. Multiple battery cells 201 are arranged in the multiple folded spaces.

[0073] To ensure that each battery cell 201 can directly contact the heating area 101, preferably one or two battery cells 201 are arranged in each folding space. Furthermore, in the folded heating film 1, battery cells 201 are also arranged on the sides of the heating areas 101 at both ends away from the folding space.

[0074] The function of the heating film 1 is to generate uniform heat when the battery pack is at a low temperature and transfer it to the battery cell 201, so that the battery cell module 2 is maintained at a suitable temperature and the reaction activity of the internal chemical substances of the battery pack is improved.

[0075] A through hole 1026 is provided at each folding connection area 102 of the heating film. When the heating film 1 is folded and arranged in an S-shaped direction along the folding edge 1027 of the folding connection area 102, due to the existence of the through hole 1026, and the folding edge 1027 is located at the edge of the through hole 1026, or can pass through the through hole 1026, the material consumption of the heating film at the folding edge 1027 is effectively reduced, and the size of the material folded along the folding edge 1027 is reduced, thereby effectively reducing the stress of the heating film at the folding edge 1027 (the folding edge is the bending corner of the heating film 1), facilitating folding and assembly, and realizing the continuous bending operation of the heating film 1; and avoiding the heating area 101 from being arched under the action of the stress, ensuring the fitting effect between the heating area 101 and the surface of the battery cell 201, and being able to transfer heat to the battery cell 201 well; at the same time, the through hole 1026 provided reduces the self-gravity of the heating film 1, and ensures the energy density of the battery pack.

[0076] In certain embodiments of the present application, a plurality of through holes 1026 are provided along the extension direction of the folded edge 1027 .

[0077] It should be noted that the extending direction of the folded edge 1027 is the direction indicated by the arrow in FIG. 1 .

[0078] At each folding connection area 102, only one through hole 1026 can be provided, which can effectively reduce the number of openings; of course, multiple through holes 1026 can also be provided, which can effectively reduce the opening size of the through hole 1026 and ensure the accuracy and convenience of the manufacturing process.

[0079] Furthermore, along the extension direction of the folded edge 1027 , the ratio of the total length of the through hole 1026 to the length of the folded edge 1027 is 0.5-0.9.

[0080] It should be noted that the length of the folded edge 1027 is the length of the folded connection area 102 .

[0081] Limiting the ratio of the total length of the through hole 1026 to the length of the folding edge 1027 within the above range can effectively reduce the stress of the heating film at the folding edge 1027 while ensuring that the through hole 1026 will not penetrate the entire heating film, thereby ensuring the reliability of the overall connection of the heating film.

[0082] Preferably, one through hole 1026 is provided and is located in the central area of ​​the folding connection area 102 .

[0083] As described above, the uniform force effect of the folding edges 1027 on both sides of the folding connection area 102 is ensured, thereby ensuring the consistency and stability of the assembly of the heating film 1 and the battery cell 201.

[0084] Please refer to FIG. 1 . In some embodiments of the present application, the corners of the through hole 1026 are chamfered.

[0085] Furthermore, the through hole 1026 is a rectangular through hole; and the corners of the through hole 1026 are rounded.

[0086] As described above, the disadvantage of stress concentration at the corners of the through hole 1026 is avoided, thereby avoiding the disadvantage of the heating film 1 being pulled by external force and the corners of the through hole 1026 being easily torn.

[0087] Referring to Figures 1 and 3 , in certain embodiments of the present application, a heating film 1 includes a protective layer 103, a heating core 104, and an electrical connector 105. Two protective layers 103 are stacked. The heating core 104 is disposed between the two protective layers 103, with an electrical connection end 1041 of the heating core 104 located in the folded connection region 102. The electrical connector 105 is electrically connected to the electrical connection end 1041.

[0088] It should be noted that the protective layer 103 is generally made of PI covering film (polyimide) or PET covering film (high-temperature resistant polyester), which is a soft and flexible insulating substrate that wraps the heating core 104 for the purpose of isolation and insulation protection.

[0089] An avoidance hole is provided on one of the protective layers 103 of the heating film 1 , and the avoidance hole is opposite to the electrical connection end 1041 , so as to expose the electrical connection end 1041 and realize a convenient and fast electrical connection between the electrical connector 105 and the electrical connection end 1041 .

[0090] The heating core 104 has two electrical connection terminals 1041, one positive and one negative. Correspondingly, two electrical connectors 105 are provided, one positive and one negative. A relief hole is provided in one of the protective layers 103, positioned opposite the electrical connection terminals 1041 to facilitate electrical connection between the positive and negative electrical connectors, and between the positive and negative electrical connectors. The heating current is then supplied to the heating core 104 via the positive and negative electrical connectors.

[0091] The heating core 104 includes multiple heating parts that provide heat; the multiple heating parts are arranged one-to-one with the multiple heating areas 101. The folding connection area 102 is an area that does not provide heat, but wiring needs to be arranged in the folding connection area 102 to connect the multiple heating parts in series.

[0092] The electrical connection end 1041 of the heating core 104 is formed in the folding connection area 102, so that the electrical connection module of the folded heating film 1 can be integrated at the end of the heating film 1 and located outside the folding space, which is not only convenient for connection with an external power supply, but also will not interfere with the folding setting of the heating film 1, nor will it affect the close fitting effect between the heating area 101 and the surface of the battery cell 201; at the same time, it will not occupy the area of ​​the heating part of the heating core 104, thereby ensuring the comprehensive and uniform heating effect of the heating area 101 on the battery cell 201.

[0093] Preferably, counting from the starting end of the folding setting of the heating film 1 , the first folding connection area 102 of the heating film is the first folding connection area 1021 ; the two electrical connection ends 1041 of the heating core 104 are both formed in the first folding connection area 1021 .

[0094] Referring to FIG. 1 , in certain embodiments of the present application, a temperature switch 106 is connected to the electrical connector 105. When the temperature is higher than a first set value, the temperature switch 106 is disconnected, and the heating film 1 stops heating. When the temperature is lower than a second set value, the temperature switch 106 is closed, and the heating film 1 resumes heating.

[0095] It should be noted that the temperature switch is composed of a heat-conducting plastic shell, a bimetallic element with silver alloy contacts welded to it, a conductive bracket, an insulating fixing seat, a static contact piece, and a heat-resistant wire. When the current passes through the bimetallic element with impedance and encounters abnormal operation, as the current increases or the ambient temperature rises to the first set value, the bimetallic element quickly actuates, the silver alloy contact opens, disconnects the static contact piece, and cuts off the charging circuit of the heating film 1; when the ambient temperature cools to the second set value, the silver alloy contact of the bimetallic element automatically closes and connects to the static contact piece, connecting the charging circuit of the heating film 1 and restoring the normal working state, thereby playing a role in thermal protection of the battery pack. Furthermore, the first set value and the second set value of the temperature of the heating film 1 are both within the safe operating temperature range of the battery pack.

[0096] By setting the temperature switch 106, the temperature of the battery pack during charging and discharging can be controlled within the suitable working range of the battery pack, that is, between the second set value and the first set value, thereby improving the electrical performance, safety and life of the battery pack.

[0097] Furthermore, the first set value is greater than the second set value; the first set value does not exceed 60°C; and the second set value is not less than 15°C.

[0098] Preferably, the first setting value is 60°C; the second setting value is 15°C; that is, during the charging and discharging process of the battery pack, the heating temperature of the heating film 1 is maintained in the working range of 15°C-60°C.

[0099] Please refer to FIG3 . In certain embodiments of the present application, the heating core 104 is a heating resistance wire.

[0100] It should be noted that only one heating resistor wire is used in the heating film 1 of the present application, and both the leading end and the trailing end of the heating resistor wire are electrical connection terminals 1041 .

[0101] The head end of the heating resistance wire is fixed in the first folding connection area; then the heating resistance wire is folded and arranged in different heating parts in sequence, and finally ensures that the tail end of the heating resistance wire can return to and be fixed in the first folding connection area; the fixed position of the head end of the heating resistance wire is opposite to the fixed position of the tail end of the heating resistance wire.

[0102] The heating resistor wire is generally made of SUS304 (stainless steel), copper, and alloy materials. According to the electric heat rate formula: P = RI^2, and the resistance law formula: R = ρL / S, where ρ is the resistivity of the material of the heating resistor wire, L is the length of the heating resistor wire, and S is the cross-sectional area of ​​the heating resistor wire; therefore, if you want the heating temperature of the heating zone 101 to be higher, you can reduce the cross-sectional area of ​​the heating resistor wire. Therefore, by controlling the cross-sectional area of ​​the heating resistor wire, the heating temperature of the heating zone 101 can be controlled, so that the heating temperature of the battery module 2 by the heating film 1 can be evenly distributed.

[0103] Referring to FIG. 1 , in some embodiments, the electrical connector 105 is a connecting wire.

[0104] It should be noted that the connecting wire is generally made of extra-soft silicone wire; its material is soft and easy to assemble and weld with the electrical connection end 1041 of the heating core 104.

[0105] Furthermore, the electrical connector 105 can also be replaced with an FPC connecting board; the FPC connecting board is electrically connected to the control circuit board 4 to connect to the external circuit through the control circuit board 4 to provide heating current for the heating core 104.

[0106] Referring to FIG. 1 , in some embodiments, an insulating protective layer is provided at the connection between the electrical connector 105 and the electrical connection terminal 1041. A first insulating protective layer is provided at the weld between the positive connecting wire and the head end of the heating resistor wire; a second insulating protective layer is provided at the weld between the negative connecting wire and the tail end of the heating resistor wire.

[0107] As described above, short circuit contact between two adjacent electrical connectors 105 , ie, the positive electrode connecting wire and the negative electrode connecting wire, can be avoided.

[0108] Furthermore, insulating glue is applied to the electrical connection between the electrical connector 105 and the electrical connection end 1041 ; the insulating glue is cured to form an insulating protective layer.

[0109] Please refer to Figures 1 and 3-5. In some embodiments of the present application, a positioning hole 1017 is provided on the heating film 1 so that when the heating film 1 and the battery cell 201 are assembled, the positioning hole 1017 is aligned with the positioning point of the assembly jig.

[0110] It should be noted that the positioning hole 1017 passes through the heating film 1 ; the positioning hole 1017 is provided in the heating area 101 ; and there are multiple positioning holes 1017 , forming three positioning portions arranged in a triangle.

[0111] Preferably, starting from the starting end of the folded arrangement of the heating film 1, the first heating zone of the heating film 1 is the first heating zone, and the second heating zone 101 is the second heating zone. Positioning holes 1017 are provided in the second heating zone. The heating resistor wire is folded and arranged in the second heating zone to avoid the positioning holes 1017.

[0112] The assembly jig has positioning protrusions formed at the positioning points that mate with the positioning holes 1017. During assembly, a battery cell 201 is first placed on the assembly jig; the first heating zone of the heating film 1 is then placed on the surface of the battery cell 201. At this point, the positioning holes 1017 in the second heating zone of the heating film 1 are aligned with the positioning points of the assembly jig, thereby achieving precise placement of the heating film 1 and ensuring the assembly accuracy between the heating film 1 and the battery cell 201.

[0113] Please refer to Figures 4-5 . In some embodiments of the present application, adhesive members 107 are provided on both the front and back sides of the heating zone 101 .

[0114] It should be noted that the adhesive member 107 is a heat-conductive double-sided adhesive adhered to the heating film 1 .

[0115] By providing thermally conductive double-sided tape, the tight fit between the heating film 1 and the battery cell 201 can be ensured, thereby efficiently conducting the heat generated by the heating film 1 to the battery cell 201; at the same time, it also makes the connection of the entire battery cell module 2 more secure, thereby enhancing the strength of the overall structure.

[0116] Furthermore, the thickness of the thermally conductive double-sided adhesive is 0.03mm-0.07mm. Preferably, the thickness of the thermally conductive double-sided adhesive is 0.05mm, or as small as possible, so that the size of the assembled battery pack can be small, which is more in line with the application scenario requirements.

[0117] Furthermore, in addition to using thermally conductive double-sided adhesive, the adhesive member 107 may also be made of hot melt adhesive.

[0118] 4-5 , further, along the length direction of the battery cell 201 , the heating area 101 includes a first end and a second end. Adhesives 107 are bonded to the heating area 101 at intervals near the first end and near the second end.

[0119] The above arrangement can, on the one hand, reduce the area of ​​consumables and lower costs; on the other hand, it can make the heating film 1 fit closely with the battery cell as much as possible to provide heat conduction efficiency; after the battery cell 201 is charged and discharged for a cycle, the battery cell 201 will expand and become larger. Usually, the middle part of the battery cell 201 will bulge first. If the adhesive 107 is bonded to the middle position of the battery cell 201, it will affect the expansion of the battery pack and there will be a safety risk; therefore, the adhesive 107 is only bonded to the two spaced ends of the battery cell 201; and under the premise of ensuring a tight connection, its size is as small as possible.

[0120] Please refer to Appendixes 19-20. In certain embodiments of the present application, the width of the cell 201 is A; the length of the cell 201 is B; and the thickness of the cell 201 is C. Please refer to FIG1 , the width of the heating zone 101 is D; the width of the folding and connecting zone 102 is E; the sum of the thicknesses of all the cell 201 accommodated within the folding space is F; and the length of the heating film 1, the length of the heating zone 101, and the length of the folding and connecting zone 102 are the same, namely G.

[0121] The length G of the heating zone 101 is less than or equal to the length B of the battery cell 201 ; the width D of the heating zone 101 is less than or equal to the width A of the battery cell 201 .

[0122] Furthermore, the length G of the folding connection area 102 is less than or equal to the length B of the battery cell 201 ; the width E of the folding connection area 102 is greater than or equal to the sum F of the thicknesses of the battery cell 201 that can be accommodated in the folding space.

[0123] It should be noted that when multiple battery cells 201 are arranged in the folding space, and battery isolation foam 202 is required between adjacent battery cells 201, the dimension F refers to the sum of the thicknesses of all battery cells 201 and all battery isolation foam 202 that can be accommodated in the folding space. Furthermore, the width dimension of the through hole 1026 is F.

[0124] As mentioned above, it can be ensured that the size of the heating film 1 does not extend beyond the edge of the battery cell 201, thereby ensuring the energy density of the battery pack; and it can be ensured that the folding space formed by the folding of the heating film 1 is exactly adapted to the number of battery cells 201 that need to be accommodated, thereby ensuring the assembly adaptability of the heating film 1 and the battery cell 201.

[0125] Furthermore, the thickness of the heating film 1 is 0.13 mm to 0.5 mm.

[0126] Since the heating power is negatively correlated with the cross-sectional area of ​​the heating resistance wire, a heating resistance wire of appropriate size is selected according to the required heating temperature, and a heating film 1 of appropriate thickness is selected accordingly.

[0127] Referring to Figure 1 , in certain embodiments of the present application, the heating zones 101 within the heating film 1 have different heating powers. Because the battery module 2 is composed of multiple stacked battery cells 201, the center battery cell 201 receives greater heat than the battery cells 201 on the sides. To ensure uniform heating, the heating powers of the different heating zones 101 within the heating film 1 are designed to be inconsistent. Generally, the heating power of the heating zones 101 at the ends of the heating film 1 is greater than the heating power of the heating zone 101 in the center region of the heating film.

[0128] It should be noted that this application uses a heating film 1 having six heating zones 101 spaced apart as an example. The sum of the heating powers of the two heating zones 101 at the ends of the heating film 1 is I, while the sum of the heating powers of the four heating zones 101 in the middle region of the heating film is J. Therefore, the heating power I / 2 of the heating zones 101 at the edges of the heating film 1 is greater, while the heating power J / 4 of the heating zones 101 in the middle region of the heating film 1 is less.

[0129] The folded connection area 102 does not need to heat the battery cell 201, but wiring needs to be arranged in this area to connect multiple adjacent heating areas 101 in series; the heating power of the wiring of each folded connection area 102 is K; K is controlled to satisfy K=I / 2-J / 4; generally K≤2W; this is the only way to keep the overall heating as uniform as possible.

[0130] A heating film 1 with 6 heating zones 101 is selected; in accordance with the assembly order, the heating film 1 includes a first heating zone 1011, a first folding connection zone 1021, a second heating zone 1012, a second folding connection zone 1022, a third heating zone 1013, a third folding connection zone 1023, a fourth heating zone 1014, a fourth folding connection zone 1024, a fifth heating zone 1015, a fifth folding connection zone 1025, and a sixth heating zone 1016. The above-mentioned heating film 1 is assembled with 12 battery cells 201. In order of assembly, the 12 battery cells 201 are respectively the first battery cell 2011, the second battery cell 2012, the third battery cell 2013, the fourth battery cell 2014, the fifth battery cell 2015, the sixth battery cell 2016, the seventh battery cell 2017, the eighth battery cell 2018, the ninth battery cell 2019, the tenth battery cell 20110, the eleventh battery cell 20111, and the twelfth battery cell 20112.

[0131] Please refer to Figures 6-9. The steps for assembling the heating film 1 and the 12 battery cells 201 are as follows:

[0132] Step 1: First, position and place the first battery cell 2011 on the assembly jig;

[0133] Step 2: Align the positioning holes 1017 on the heating film 1 with the positioning points on the assembly jig, and adhere the reverse side of the first heating area 1011 to the first battery cell 2011;

[0134] Step 3: stack the second battery cell 2012 on the front of the first heating area 1011;

[0135] Step 4: Applying cell isolation foam 202 on the surface of the second cell 2012;

[0136] Step 5: stacking the third battery cell 2013;

[0137] Step 6: Fold the two folded edges 1027 of the first folded connection area 1021 in sequence, so that the heating film 1 is folded back to the surface of the third battery cell 2013. At this time, the front side of the second heating area 1012 is bonded to the third battery cell 2013; (Steps 1-6 are shown in Figure 6)

[0138] Step 7: stacking the fourth battery cell 2014 on the reverse side of the second heating zone 1012;

[0139] Step 8: Apply the cell isolation foam 202 on the surface of the fourth cell 2014;

[0140] Step 9: stacking the fifth battery cell 2015;

[0141] Step 10: Fold the two folded edges 1027 of the second folded connection area 1022 in sequence, so that the heating film 1 is folded back to the surface of the fifth battery cell 2015. At this time, the reverse side of the third heating area 1013 is bonded to the fifth battery cell 2015.

[0142] Step 11: stacking the sixth battery cell 2016 on the front of the third heating zone 1013;

[0143] Step 12: Applying cell isolation foam 202 to the surface of the sixth cell 2016; (Steps 7-12 are shown in FIG. 7 )

[0144] Step 13: stack the seventh battery cell 2017;

[0145] Step 14: Fold the two folded edges of the third folding connection area 1023 in sequence, so that the heating film 1 is folded back to the surface of the seventh battery cell 2017. At this time, the front side of the fourth heating area 1014 is bonded to the seventh battery cell 2017.

[0146] Step 15: stacking the eighth battery cell 2018 on the reverse side of the fourth heating zone 1014;

[0147] Step 16: Applying cell isolation foam 202 on the surface of the eighth cell 2018;

[0148] Step 17: Stack the ninth battery cell 2019;

[0149] Step 18: Fold the two folded edges 1027 of the fourth folding connection area 1024 in sequence, so that the heating film 1 is folded back to the surface of the ninth battery cell 2019. At this time, the reverse side of the fifth heating area 1015 is bonded to the ninth battery cell 2019. (Steps 13-18 are shown in FIG8 )

[0150] Step 19: stacking the tenth battery cell 20110 on the front of the fifth heating zone 1015;

[0151] Step 20: Applying cell isolation foam 202 on the surface of the tenth cell 20110;

[0152] Step 21: stacking the eleventh battery cell 20111;

[0153] Step 22: Fold the two folded edges 1027 of the fifth folded connection area 1025 in sequence, so that the heating film 1 is folded back to the surface of the eleventh battery cell 20111. At this time, the front side of the sixth heating area 1016 is bonded to the eleventh battery cell 20111.

[0154] Step 23: Overlay the twelfth battery cell 20112 on the back of the sixth heating zone 1016, thus completing the assembly of the heating film 1 and the 12 battery cells 201. (Steps 19-23 are shown in FIG9 )

[0155] Through the above assembly steps, a semi-finished battery core unit 20 is obtained, which is composed of an integrally structured battery cell module 2 and a folded heating film 1 .

[0156] The thickness of the cell isolation foam 202 is M; the thickness of the cell unit 201 is C; M and C satisfy: M*70%=C*2+C*10%*2.

[0157] Please refer to Figures 10-12. Figure 12 shows a cross-sectional view of the assembled heating film 1 and multiple battery cells 201. As shown in Figure 12, a heating zone 101 is sandwiched between every two battery cells 201, allowing the heating film 1 to effectively provide uniform heat to each battery cell 201.

[0158] In summary, this application further provides a battery pack; the battery pack includes a cell module 2 and the heating film 1 described above. The cell module 2 includes a plurality of cell units 201 arranged in sequence. The heating film 1 sequentially forms a plurality of folded spaces along the arrangement direction of the cell units 201; the plurality of cell units 201 are disposed in the plurality of folded spaces.

[0159] Since the battery pack has the heating film 1 described above, the beneficial effects of the battery pack brought by the heating film 1 can be found above and will not be repeated here.

[0160] Referring to Figures 13 and 17 , in certain embodiments of the present application, the battery pack includes a tab welding plate 3 ; the tab welding plate 3 is located above the battery cell module 2 . The tab welding plate 3 is provided with a guide hole 301 ; the electrical connector 105 of the heating film 1 passes through the guide hole 301 .

[0161] It should be noted that the tab welding plate 3 is provided with tab holes arranged at intervals; a welding platform is formed between adjacent tab holes; and a nickel brick is provided on the welding platform.

[0162] After the heating film 1 and the cell 201 are assembled to form the semi-finished battery core unit 20, a tab welding plate 3 is placed above the semi-finished battery core unit 20 (i.e., above the cell module 2). The tabs in the cell module 2 are inserted through the tab holes of the tab welding plate 3. The tabs are then folded flat and aligned with the nickel bricks on the welding platform of the tab welding plate 3. The overlapping tabs are then connected using laser or resistance welding.

[0163] The electrical connector 105 on the heating film 1 is passed through the guide hole 301 , which plays a fixing role in leading the electrical connector 105 outward.

[0164] Please refer to Figures 13 and 17. Furthermore, an insulating sheet 6 is applied on the tab welding plate 3. The purpose of the insulating sheet 6 is to prevent the tab welding point from contacting other objects and causing a short circuit.

[0165] Tab isolation foam 5 is provided and inserted into the spaces between adjacent tabs in the plurality of battery cells 201. Tab isolation foam 5 is located at the bottom of tab welding plate 3. The provision of tab isolation foam 5 not only isolates the tabs, but also prevents the risk of tab contact and short circuit due to external vibrations. It also supports the tab welding plate 3, preventing the risk of short circuit due to contact between the tab welding plate 3 and the battery cells 201, and also strengthens the overall fixation effect.

[0166] Please refer to FIG14 and FIG17 , in some embodiments of the present application, the battery pack includes a control circuit board 4 . The electrical connector 105 of the heating film 1 is electrically connected to the control circuit board 4 .

[0167] It should be noted that the tab welding plate 3 is connected to the control circuit board 4 by welding using a signal cable 9 ; its purpose is to collect and feedback the working condition information of the battery module 2 .

[0168] The electrical connector 105 is electrically connected to the control circuit board 4, which can avoid setting up complex and lengthy connection lines on the heating film 1 to connect with the external circuit. The electrical connector 105 can be electrically connected to the external circuit through the control circuit board 4, thereby powering the heating film 1.

[0169] Furthermore, a positive electrode wire 7 and a negative electrode wire 8 are welded to the tab welding plate 3; the positive electrode wire 7 is welded to the positive electrode welding position of the tab welding plate 3, and the negative electrode wire 8 is welded to the negative electrode welding position of the tab welding plate 3; the purpose is to enable the battery module 2 to be charged and discharged normally.

[0170] Please refer to FIG14 , a connector terminal 10 is welded on the control circuit board 4 and serves as a port for external connection.

[0171] Please refer to Figures 15 and 17. A protective component is provided on the outer surface of the battery cell module 2, and finally a battery core unit 21 is obtained. The protective component is an auxiliary foam component applied to the outer surface of the battery cell module 2. The auxiliary foam component includes a front auxiliary foam 13, a rear auxiliary foam 14, a left auxiliary foam 15, a right auxiliary foam 16 and a bottom auxiliary foam 17. By providing a protective component, the battery core unit 21 can be prevented from being punctured or scratched by the lower shell 19 when it is installed into the lower shell 19; at the same time, it also has a buffering and shock-absorbing effect, which can prevent the battery pack from being subjected to external vibrations, resulting in the risk of the battery cell module 2 being punctured or scratched by the lower shell 19.

[0172] The above description is merely an embodiment of the present application, and the battery core unit 21 built into the battery pack of the present application may have various modifications and variations.

[0173] Referring to Figures 16-17 , a notch is further formed in the upper left corner of the rear auxiliary foam 14 to accommodate the temperature switch 106 on the heating film 1. The temperature switch 106 is located on the side of the battery module 2, and the thickness of the rear auxiliary foam 14 can protect the temperature switch 106 from being squeezed by the lower housing 19.

[0174] Refer to Figure 18 . Install control circuit board screws 11 onto control circuit board 4. The control circuit board 4 and upper housing 18 are securely connected via control circuit board screws 11. Insert connector terminal screws 12 through upper housing 18. Connector terminals 10 are securely fastened to upper housing 18 via connector terminal screws 12. Finally, place upper housing 18 over lower housing 19 and connect them together via laser welding, ultrasonic welding, gluing, or other methods. This completes the assembly of the battery pack.

[0175] The components and devices involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the accompanying drawings. As will be appreciated by those skilled in the art, these components and devices can be connected, arranged, or configured in any manner. Words such as "including," "comprising," "having," and the like are open-ended words that mean "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0176] It should also be noted that in the device of the present application, each component can be decomposed and / or reassembled, and such decomposition and / or reassembly should be regarded as equivalent solutions of the present application.

[0177] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0178] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

[0179] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A heating film, characterized in that: Used to heat a plurality of battery cell monomers (201) arranged in sequence; the heating film comprises a plurality of heating zones (101) arranged at intervals and a folded connection zone (102) located between two adjacent heating zones (101) among the plurality of heating zones (101); The edge of the folded connection area (102) adjacent to each heating area (101) of the two adjacent heating areas (101) is a folded edge; the heating film can be folded along the folded edge; Wherein, a through hole (1026) is provided on the heating film; and the folded edge is located at the edge of the through hole (1026) or passes through the through hole (1026).

2. The heating film according to claim 1, characterized in that: Along the extension direction of the folded edge, a plurality of through holes (1026) are provided; and / or, Along the extension direction of the folding edge, the ratio of the total length of the through hole (1026) to the length of the folding edge is 0.5-0.

8.

3. The heating film according to claim 1 or 2, characterized in that: The corners of the through hole (1026) are chamfered.

4. The heating film according to any one of claims 1 to 3, characterized in that The heating film comprises: Two protective layers (103) arranged in a stacked manner; A heating core (104) is disposed between the two protective layers (103), and an electrical connection end (1041) of the heating core (104) is located in the folded connection area (102); An electrical connector (105) is electrically connected to the electrical connection end (1041).

5. The heating film according to claim 4, characterized in that: The electrical connector (105) is connected to a temperature switch (106); When the temperature is higher than a first set value, the temperature switch (106) is disconnected and the heating film stops heating; when the temperature is lower than a second set value, the temperature switch (106) is closed and the heating film heats.

6. The heating film according to claim 4 or 5, characterized in that: The heating core (104) is a heating resistance wire; and / or, The electrical connector (105) is a connecting wire; and / or, An insulating protective layer is provided at the connection between the electrical connector (105) and the electrical connection end (1041).

7. The heating film according to any one of claims 1 to 6, characterized in that The heating film is provided with a positioning hole (1017) so that when the heating film and the plurality of battery cell monomers (201) are assembled, the positioning hole (1017) is positioned with a positioning point of an assembly jig.

8. The heating film according to any one of claims 1 to 7, characterized in that Adhesive components (107) are provided on the front and back surfaces of the heating zone (101).

9. The heating film according to claim 8, characterized in that: Along the length direction of each battery cell (201) in the plurality of battery cell units (201), the heating area (101) comprises a first end and a second end that are opposite to each other; The adhesive members (107) are arranged at intervals near the first end and near the second end of the heating zone (101).

10. The heating film according to any one of claims 1 to 9, characterized in that The length dimension of the heating zone (101) is not greater than the length dimension of each battery cell (201) among the plurality of battery cell units (201); the width dimension of the heating zone (101) is not greater than the width dimension of the battery cell unit (201); and / or, The length dimension of the folding connection area (102) is not greater than the length dimension of each battery cell (201) in the plurality of battery cells (201); in the folded heating film, the folding connection area (102) and the two adjacent heating areas (101) enclose a folding space; the width dimension of the folding connection area (102) is not less than the sum of the thickness dimensions of all the battery cells (201) that can be accommodated in the folding space; and / or, The thickness of the heating film is 0.13mm-0.5mm.

11. The heating film according to any one of claims 1 to 10, characterized in that The heating power of the heating zones (101) located at both ends of the heating film is greater than the heating power of the heating zone (101) located in the middle area of ​​the heating film.

12. The battery pack according to any one of claims 1 to 11, characterized in that: The through hole (1026) is opened in the folding connection area (102), and along the spacing arrangement direction of the multiple heating areas (101), the width of the through hole (1026) is the same as the width of the folding connection area (102); or, the opening area of ​​the through hole (1026) exceeds the folding connection area (102), and the two edges of the through hole (1026) fall into the two adjacent heating areas (101) respectively.

13. A battery pack, characterized in that: Comprising a battery cell module (2) and a heating film (1) according to any one of claims 1 to 12; The battery cell module (2) comprises a plurality of battery cell monomers (201) arranged in sequence; Along the arrangement direction of the plurality of battery cell monomers (201), the heating film (1) sequentially forms a plurality of folding spaces; the plurality of battery cell monomers (201) are arranged in the plurality of folding spaces.

14. The battery pack according to claim 13, characterized in that: The battery pack further comprises a pole lug welding plate (3); the pole lug welding plate (3) is located above the battery core module (2); and a guide hole (301) is provided on the pole lug welding plate (3); The heating film (1) comprises an electrical connector (105); the electrical connector (105) passes through the guide hole (301).

15. The battery pack according to claim 13 or 14, characterized in that: The battery pack also includes a control circuit board (4); The electrical connector (105) in the heating film (1) is electrically connected to the control circuit board (4).

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