Battery thermal management system and battery system

Abstract

The utility model relates to a battery thermal management system and a battery system.The battery thermal management system comprises a heating film, a heat conduction connecting piece, a first heating piece and a second heating piece, and the heating film comprises a plurality of foldable transition parts and non-transition parts which are sequentially arranged at intervals in the length direction of the heating film; the heat conduction connecting piece is located between the shell of the battery cell and the heating film, the transition part is attached to the outer surface of the side, in the width direction of the battery cell, of the battery cell and the corner of the side, in the width direction, of the battery cell through the heat conduction connecting piece, and the non-transition part is attached to the outer surface of the side, in the length direction of the battery cell, of the battery cell through the heat conduction connecting piece; the first heating element is arranged in the non-transition part, the second heating element is arranged in the transition part, the second heating element and the first heating element are used for heating the surfaces, attached to the battery cell, of the second heating element and the first heating element respectively, and the fracture stress of the second heating element is larger than that of the first heating element. The battery thermal management system can improve the heating effect of the heating film on the battery module.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular to a battery thermal management system and a battery system. Background Art

[0002] Lithium-ion batteries are widely used in new energy vehicles and energy storage fields due to their high energy density and environmental friendliness. However, in a low-temperature environment, the capacity of lithium batteries will be limited, and low-temperature charging may cause the battery to explode.

[0003] In the related art, in order to solve the problem that the capacity of lithium batteries is limited in low temperature environments and that low temperature charging may cause explosions, technicians usually use a heating film to wrap the battery module, that is, wrap the side surface of the shell of each battery cell in the battery module with a heating film to heat the temperature of the entire battery module to above 0°C, so as to improve the problem of lithium battery capacity attenuation under low temperature conditions and reduce the risk of battery explosion. However, when the heating film is used to wrap the shell of the square shell battery, the heating film is easily damaged when it is bent at the corners of the battery cell, causing the failure of the heating film and affecting the heating effect of the heating film. Utility Model Content

[0004] Based on this, it is necessary to provide a battery thermal management system and a battery system to address the problem that heating a battery module using a heating film in a low temperature environment may cause the heating film to be damaged and affect the heating effect of the battery module.

[0005] In a first aspect, the present application provides a battery thermal management system, which is applied to a battery module including a plurality of battery cells stacked in sequence, and the battery thermal management system includes:

[0006] The heating film comprises a plurality of foldable transition portions and non-transition portions sequentially arranged at intervals along its length direction, and the heating film is used to be attached to a plurality of outer surfaces of the battery core;

[0007] A first heating element is arranged in the non-transition portion;

[0008] The second heating element is arranged in the transition part. The second heating element and the first heating element are respectively used to heat the side that is in contact with the battery cell, wherein the breaking stress of the second heating element is greater than the breaking stress of the first heating element.

[0009] In one embodiment, the battery thermal management system also includes a thermally conductive connector, which is located between the shell of the battery cell and the heating film. The thermally conductive connector adheres the transition portion to the outer surface of the battery cell on one side along its own width direction and the corner of the battery cell on one side in the width direction. The thermally conductive connector also adheres the non-transition portion to the outer surface of the battery cell on one side along its own length direction.

[0010] In one embodiment, the thermally conductive connector includes a thermally conductive adhesive layer, and the thickness of the thermally conductive adhesive layer in the transition portion is greater than the thickness of the thermally conductive adhesive layer in the non-transition portion.

[0011] In one embodiment, the thickness of the transition portion is greater than the thickness of the non-transition portion.

[0012] In one embodiment, the area of ​​the fractured cross section of the second heating element is greater than the area of ​​the fractured cross section of the first heating element; preferably, the first heating element comprises a heating wire, and the second heating element comprises a heating plate.

[0013] In one of the embodiments, the heating film further includes a foldable protrusion, which is connected to the non-transition portion. After the protrusion is folded, it fits with the bottom surface of the battery cell, and a third heating element is provided in the protrusion.

[0014] In one embodiment, the fracture stress of the third heating element is not less than the fracture stress of the second heating element, and the heating power of the second heating element and / or the third heating element is greater than the heating power of the first heating element.

[0015] In one embodiment, the battery cell includes a shell and an insulating film wrapping the shell, and the insulating film located on the side and / or bottom of the battery cell is provided with an opening.

[0016] In a second aspect, the present application provides a battery system, comprising any one of the battery thermal management systems and battery modules provided in the first aspect, the battery module comprising a plurality of battery cells stacked sequentially along its length direction, and the battery system further comprising an insulating film arranged on the shell, the insulating film being located between the shell and the heating film.

[0017] In one of the embodiments, the battery system further includes a box body, which is used to accommodate the battery thermal management system and the battery module, and the battery module is connected to the inner wall of the box body through a fixing member.

[0018] The battery thermal management system includes a heating film, a first heating element and a second heating element. The heating film includes a plurality of foldable transition parts and non-transition parts arranged in sequence along its length direction. The heating film is used to fit with multiple outer surfaces of the battery cell. The first heating element is arranged in the non-transition part, and the second heating element is arranged in the transition part. The second heating element and the first heating element are respectively used to heat the side that fits with the battery cell, wherein the fracture stress of the second heating element is greater than the fracture stress of the first heating element. The transition part and the non-transition part of the heating film in the battery thermal management system are respectively tightly fitted with the outer surfaces of the corresponding battery cells, thereby ensuring the heating effect of the heating film on the battery cell; since the fracture stress of the second heating element is greater than the fracture stress of the first heating element, the heating film located at the corner of the outer surface of the battery cell is not easily damaged even if it is in a bent and folded state under external force, thereby ensuring the tightness of the fit between the second heating element and the corner of the outer surface of the battery cell, thereby improving the heating uniformity of the battery cell and the battery module, and ensuring the heating effect of the heating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] FIG. 1 is a schematic structural diagram for illustrating the connection relationship between battery cells in a battery module in some embodiments of the present application.

[0021] FIG. 2 is a schematic structural diagram for illustrating the connection relationship between the heating film and the battery cell in some embodiments of the present application.

[0022] FIG. 3 is a schematic diagram of an exploded structure for illustrating the connection relationship between a heating film and a battery module in some embodiments of the present application.

[0023] FIG. 4 is a schematic structural diagram for illustrating the connection relationship between the transition portion and the non-transition portion in the heating film in some embodiments of the present application.

[0024] FIG. 5 is a schematic structural diagram for illustrating the location of openings on an insulating film in some embodiments of the present application.

[0025] FIG. 6 is a schematic structural diagram showing the connection relationship between the protruding portion and the non-transition portion in the heating film in some embodiments of the present application.

[0026] FIG. 7 is a schematic structural diagram of the connection relationship between a battery module, an end plate, and a fastener in some embodiments of the present application.

[0027] Description of Figure Numbers:

[0028] 100, battery module; 110, battery cell; 110a, main surface; 110b, side surface; 110c, bottom surface; 114, corner; 116, opening; 120, insulating film; 130, end plate; 140, fastener; 200, heating film; 210, transition part; 212, second heating element; 220, non-transition part; 222, first heating element; 230, protrusion; 232, third heating element. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0035] In order to solve the problem in the related art that the heating film is used to heat the battery module under a low temperature environment, and the heating film is easily damaged, which affects the heating effect of the battery module, in the first aspect, referring to Figures 1 to 5, an embodiment of the present application provides a battery thermal management system, including a heating film 200, a first heating element 222 and a second heating element 212, the heating film 200 includes a plurality of foldable transition portions 210 and a non-transition portion 220 sequentially arranged at intervals along its own length direction, the heating film 200 is used to be bonded to multiple outer surfaces of the battery cell 110, the first heating element 222 is arranged in the non-transition portion 220, and the second heating element 212 is arranged in the transition portion 210, the second heating element 212 and the first heating element 222 are respectively used to heat their respective sides bonded to the battery cell 110, wherein the fracture stress of the second heating element 212 is greater than the fracture stress of the first heating element 222.

[0036] The battery cell 110 is in a rectangular shape, and the shell of the battery cell 110 includes two main surfaces 110a, two side surfaces 110b and a bottom surface 110c. The main surface 110a has the largest surface area, and the main surface 110a is parallel to the length direction of the battery cell 110, and one of the bottom surfaces 110c is also the upper surface of the battery cell 110. The heating film 200 is a flexible film that is easy to fold and bend. The heating film 200 can be a PI heating film (Polyimide Heating Film) or a PTC heating film (Positive Temperature Coefficient Heating Film). The PI heating film is a heating film made of polyimide material, which has excellent high temperature resistance and stable insulation performance. The PI heating film can be heated by powering on and can quickly generate uniform heat; the PTC heating film has a positive temperature coefficient effect, and its resistance value can rise sharply with the increase of temperature, thereby limiting the flow of current to achieve the effect of self-heating. The length of the transition part 210 in the heating film 200 can be greater than the width of the battery cell 110 to ensure that the transition part 210 is fully attached to the outer surface of the battery cell 110 on one side in the width direction. Fracture stress refers to the maximum stress that a material can withstand when it breaks. The fracture stress of the second heating element 212 is greater than the fracture stress of the first heating element 222, that is, the second heating element 212 is less likely to break than the first heating element 222 under the same external force; when the heating film 200 is wrapped around the surface of the battery cell 110, in order to make the transition part 210 fit tightly at the corner 114 of the battery cell 110, a certain external force needs to be applied to the transition part 210. The fracture stress of the second heating element 212 is relatively large and is not easy to break or damage, ensuring the normal use of the heating film 200.

[0037] Specifically, the winding method of the heating film 200 in each battery module 100 can refer to FIG. 3. When assembling the battery module 100, the non-transition portion 220 of the heating film 200 can be bonded to the main surface 110a of the first battery cell 110 along one side of its length direction from one end of the battery module 100 through a thermally conductive connector, and then the transition portion 210 of the heating film 200 can be bonded to the side surface 110b of the battery cell 110 along one side of its width direction, and then the other non-transition portion 220 of the heating film 200 can be bonded to the main surface 110a of the other side of the battery cell 110 along the length direction. The heating film 200 is laminated, and then the other transition part 210 of the heating film 200 is laminated with the side 110b of the second battery cell 110 along its own width direction, and the remaining non-transition part 220 and the transition part 210 are laminated on the outer surface of the remaining battery cells 110 in sequence according to the above method, so that the heating film 200 wraps multiple outer surfaces of each battery cell 110 in the battery module 100. Since the surface area of ​​the main surface 110a of the battery cell 110 is larger than the surface area of ​​the side 110b and the bottom surface 110c, such a winding method can ensure the heating effect of the battery module 100 as a whole. Moreover, when the heating film 200 heats the battery cell 110 and the battery module 100 as a whole according to the winding method of Figure 3, the heating film 200 only needs to be bent at the transition part 210, and since the second heating element 212 is arranged in the transition part 210, the fracture stress of the second heating element 212 needs to be set to be greater than the fracture stress of the first heating element 222. Moreover, this winding method allows the battery module to be heated more evenly as a whole.

[0038] In some embodiments, the battery thermal management system also includes a thermally conductive connector, which is located between the battery cell 110 and the heating film 200. The thermally conductive connector adheres the transition portion 210 to the outer surface of the battery cell 110 on one side along its width direction and the corner 114 of the battery cell 110 on one side in the width direction. The thermally conductive connector also adheres the non-transition portion 220 to the outer surface of the battery cell 110 on one side along its length direction.

[0039] In this embodiment, the heating film 200 is tightly connected to the shell of the battery cell 110 through a heat-conductive connector, so that the first heating element 222 and the second heating element 212 are respectively tightly fitted to the outer surfaces of the corresponding battery cells 110, thereby ensuring the heating effect of the first heating element 222 and the second heating element 212 on the battery cell 110; and because the fracture stress of the second heating element 212 is greater than the fracture stress of the first heating element 222, the heating film 200 located at the corner 114 of the outer surface of the battery cell 110 is not easily damaged even in a bent and folded state, thereby ensuring the tightness of the fit between the second heating element 212 and the corner 114 of the outer surface of the battery cell 110, thereby improving the heating uniformity of the battery cell 110 and the battery module 100.

[0040] In some embodiments, the thermally conductive connector includes a thermally conductive adhesive layer, and the thickness of the thermally conductive adhesive layer of the transition portion 210 is greater than the thickness of the thermally conductive adhesive layer of the non-transition portion 220 .

[0041] Among them, the material of the thermal conductive adhesive layer can be silicone. Silicone has high elasticity, which makes it highly energy-absorbing and can absorb the external force applied to the transition part 210, further reducing the possibility of the transition part 210 being damaged under the action of external force; at the same time, silicone has excellent bonding properties and can tightly bond the battery cell 110 and the heating film 200 together to ensure the heat conduction efficiency, and silicone has good thermal conductivity, which can make the heat generated by the heating film 200 quickly and evenly transferred to the battery cell 110, thereby ensuring the heating efficiency of the heating film 200 to the battery module 100.

[0042] Specifically, since there is a corner 114 between adjacent outer surfaces of the battery cell 110, that is, there is a certain curvature, a large gap may appear in the thermal conductive adhesive layer at the corner 114. Therefore, the thickness of the thermal conductive adhesive layer of the transition part 210 is set to be greater than the thickness of the thermal conductive adhesive layer of the non-transition part 220. This can fill these gaps and ensure the uniformity of heat conduction, thereby ensuring the uniformity of the battery module 100 when heated.

[0043] In this embodiment, the heating film 200 is tightly bonded to the shell of the battery cell 110 through the thermal conductive adhesive layer, and the thickness of the thermal conductive adhesive layer of the transition part 210 is set to be greater than the thickness of the thermal conductive adhesive layer of the non-transition part 220, which can ensure that the transition part 210 is fully attached to the corner 114 of the outer surface of the battery cell 110, so that the heat can be evenly transferred to the corner 114 of the outer surface of the battery cell 110, thereby ensuring the uniformity of the battery module 100 when heated. In addition, due to the existence of the curvature, the corner 114 of the outer surface of the battery cell 110 will produce a higher stress than the rest of the battery cell 110. The thickness of the thermal conductive adhesive layer at the corner 114 is set to be greater than the thickness of the thermal conductive adhesive layer of the rest of the battery cell 110, which can make the thermal conductive adhesive layer at the corner 114 bear greater pressure, thereby helping to alleviate the extrusion force generated when the battery cells 110 are bundled into the battery module 100, thereby playing a good protective role for the thermal conductive adhesive layer and the heating film 200.

[0044] 2 and 3 , in some embodiments, the thickness of the transition portion 210 is greater than the thickness of the non-transition portion 220 .

[0045] Specifically, since the area of ​​the side surface 110b of the battery cell 110 is smaller than the area of ​​the main surface 110a of the battery cell 110, that is, the surface area of ​​the transition portion 210 is smaller than the surface area of ​​the non-transition portion 220, that is to say, the surface area covered by the heating film 200 in these two directions is also different, so different thicknesses of the heating film 200 are set to better match the side surface areas of the battery cell 110 in different directions, thereby providing a more uniform heating effect.

[0046] In this embodiment, the thickness of the transition portion 210 is set to be greater than the thickness of the non-transition portion 220, so that the thicker heating film 200 provides more heat in the width direction of the battery cell 110, thereby transferring the heat to the main surface 110a of the battery cell 110 more evenly, thereby balancing the heating uniformity of the battery cell 110 and ensuring the consistency of the overall heating effect of the battery cell 110.

[0047] 4 , in some embodiments, the area of ​​the fractured cross section of the second heating element 212 is greater than the area of ​​the fractured cross section of the first heating element 222 .

[0048] The fracture cross section refers to the fracture surface of the material after the material is broken by the fracture stress, which can also be understood as the cross section of the material. The larger the fracture cross section of the material, the stronger its toughness and tensile resistance. The area of ​​the fracture cross section of the second heating element 212 is greater than the area of ​​the fracture cross section of the first heating element 222, that is, the area of ​​the cross section of the second heating element 212 is greater than the area of ​​the cross section of the first heating element 222.

[0049] In this embodiment, the first heating element 222 and the second heating element 212 can use the same electric heating material, including but not limited to nickel-chromium alloy, resistance alloy material, etc. Since the second heating element 212 is arranged close to the corner 114 of the outer surface of the battery cell 110, and it can be known from the above content that the stress at the corner 114 of the battery cell 110 is relatively large, making the second heating element 212 more susceptible to distortion, damage or fracture, so the fracture surface of the second heating element 212 is set to be larger than the fracture surface of the first heating element 222, which can improve the durability of the second heating element 212 at the corner 114 of the outer surface of the battery cell 110, thereby reducing the risk of damage to the second heating element 212. In addition, a larger fracture surface can provide more heat output, help compensate for the heating unevenness at the corner 114, and achieve a more uniform and consistent heating effect.

[0050] 4 , in some embodiments, the first heating element 222 includes a heating wire, and the second heating element 212 includes a heating sheet.

[0051] The heating wire and the heating plate can be made of materials such as nickel-chromium alloy, copper-nickel alloy, etc., which have good thermal conductivity and conduction performance.

[0052] Specifically, referring to FIG. 2 , FIG. 4 and FIG. 5 , a heating wire may be disposed in the transition portion 210 that is in contact with the flat portion of the side surface 110 b of the battery cell 110 , and a heating sheet may be disposed in the transition portion 210 near the corner 114 .

[0053] In this embodiment, since the fracture cross-section of the heating wire is smaller than that of the heating plate, the heating plate is less likely to be damaged under the same external force, thereby ensuring the heating effect of the transition portion 210 on the corner 114 of the outer surface of the battery cell 110 .

[0054] 5 and 6 , in some embodiments, the heating film 200 further includes a foldable protrusion 230 , which is connected to the non-transition portion 220 . After being folded, the protrusion 230 is in contact with a bottom surface 110 c of the battery cell 110 . A third heating element 232 is provided in the protrusion 230 , and a fracture stress of the third heating element 232 is not less than a fracture stress of the second heating element 212 .

[0055] The material of the protrusion 230 is consistent with that of the transition portion 210 and the non-transition portion 220, which are all PI heating film 200 (Polyimide Heating Film) or PTC heating film 200 (Positive Temperature Coefficient Heating Film). The third heating element 232 includes a heating sheet. Since the bottom surface 110c of the battery cell 110 bears the weight of the entire battery cell 110, it is usually subjected to vertical pressure and mechanical stress from the upper components. Therefore, the third heating element 232 located on the bottom surface 110c of the battery cell 110 needs sufficient strength and fracture stress to avoid fracture or damage during operation. In addition, in order to ensure the uniformity of the heating of the battery cell 110 as a whole, when the protrusion 230 is bent and folded to fit the bottom surface 110c of the battery cell 110, since the protrusion 230 is also bent, the fracture stress of the heating sheet needs to be set to be not less than the fracture stress of the second heating element 212.

[0056] Specifically, when the heating film 200 is neatly spread out on a horizontal plane, the protrusion 230 is located below the non-transition portion 220. When the non-transition portion 220 is in contact with the main surface 110a of the battery cell 110 on one side along its own length direction, the protrusion 230 can be bent downward until the protrusion 230 is in contact with the bottom surface 110c of the battery cell 110, so that the third heating element 232 heats the bottom surface 110c of the battery cell 110, which is more conducive to heating the entire battery module 100.

[0057] In this embodiment, the cooperation between the protrusion 230 and the third heating element 232 is used to achieve uniform heating of the bottom surface 110 c of the battery cell 110 , thereby further improving the uniformity of heating of the entire battery module 100 .

[0058] 6 , in some embodiments, the heating power of the second heating element 212 and / or the third heating element 232 is greater than the heating power of the first heating element 222 .

[0059] Among them, according to the above content, it can be known that the first heating element 222 includes a heating wire, the second heating element 212 includes a heating plate, and the third heating plate includes a heating plate. If it is necessary to increase the heating power of the second heating element 212 and / or the third heating element 232, it can be achieved by increasing the arrangement density of the heating plate and / or the heating plate. Similarly, the adjustment of the heating power of the first heating element 222 can also be achieved by changing the arrangement density of the heating wire.

[0060] Specifically, since the surface area of ​​the bottom surface 110c of the battery cell 110 and the side surface 110b along its width direction that is in contact with the air is larger, compared with the surface on one side of the battery cell 110 along its length direction, there is usually a larger amount of heat dissipation. In order to ensure the uniformity of heating of the battery cell 110 as a whole and the battery module 100 as a whole, it is necessary to make the heating power of the second heating element 212 and / or the third heating element 232 greater than the heating power of the first heating element 222 to compensate for the heat loss caused by the faster heat dissipation speed.

[0061] In this embodiment, the heating power of the second heating element 212 and / or the third heating element 232 is set to be greater than the heating power of the first heating element 222, which is beneficial to further ensure the uniformity of heating of the battery cell 110 as a whole and the battery module 100 as a whole.

[0062] The battery thermal management system of the present application tightly connects the heating film 200 to the shell of the battery cell 110 through a thermally conductive adhesive layer, so that the first heating element 222, the second heating element 212 and the third heating element 232 are tightly fitted to the outer surfaces of the corresponding battery cells 110, thereby ensuring the heating effect of the heating film 200 on the battery cell 110 as a whole; and because the fracture stress of the second heating element 212 is greater than the fracture stress of the first heating element 222, the heating film 200 located at the corner 114 of the battery cell 110 is not Under the influence of the second heating element 212 and the third heating element 232, it is not easy to be damaged, thereby ensuring the tightness of the fit between the second heating element 212 and the corner 114 of the outer surface of the battery cell 110, thereby improving the heating uniformity of the battery cell 110 and the battery module 100; in addition, since the heating power of the second heating element 212 and / or the third heating element 232 is greater than the heating power of the first heating element 222, the fracture stress of the third heating element 232 is not less than the fracture stress of the second heating element 212, so that the uniformity of the heating of the battery cell 110 as a whole and the battery module 100 as a whole is further improved.

[0063] 5 and 7 , in some embodiments, the battery cell 110 includes a shell and an insulating film 120 wrapped around the shell, and the insulating film 120 is located between the shell and the heating film 200 .

[0064] The battery module 100 further includes end plates 130 disposed at both ends thereof, and the end plates 130 are bonded to the heating films 200 on the battery cells 110 of the two groups of the battery module 100 through thermally conductive adhesive. After bonding, the end plates 130 and the plurality of battery cells 110 can be bound together as a whole through fasteners 140 to ensure the tightness of the connection between the end plates 130 and the battery cells 110 on both sides and the tightness of the connection between the remaining battery cells 110. The fasteners 140 include binding tapes, etc. The insulating film 120 can be tightly wrapped on the outer surface of the shell through thermally conductive adhesive.

[0065] In this embodiment, a layer of insulating film 120 is first wrapped on the shell of the battery cell 110, and then the heating film 200 is wrapped, which can prevent the shell from directly contacting the heating film 200, thereby reducing the risk of accidental electric shock or short circuit; in addition, if the heating film 200 needs to be heated by electric current, the insulating film 120 can effectively isolate the electrical connection between the heating film 200 and the shell, thereby preventing short circuit.

[0066] 5 to 7 , in some embodiments, an opening 116 is provided on the insulating film 120 located on the side and / or bottom of the battery cell 110 , that is, an opening 116 is provided on the insulating film 120 located on one side of the transition portion 210 and / or the insulating film 120 located on one side of the protrusion 230 .

[0067] Specifically, as shown in FIGS. 3 and 5 , the shell of the battery cell 110 includes two main surfaces 110a, two side surfaces 110b and a bottom surface 110c. After the battery cell 110 is assembled into the battery module 100, the main surface 110a of the battery cell 110 is sandwiched in the middle of the battery module 100, and the two side surfaces 110b and the bottom surface 110c of the battery cell 110 are exposed to the outside, so that during the heating process, the heat dissipation speed of the side surfaces 110b and the bottom surface 110c of the battery cell 110 is faster. Therefore, in order to reduce the heat dissipation speed of the side surfaces 110b and the bottom surface 110c that is too fast, the main surfaces 110a, the side surfaces 110b and the bottom surface 110c are In order to prevent the possibility of temperature difference between the two surfaces 110c, it is necessary to set an opening 116 on the insulating film 120 located on the transition part 210 side and the insulating film 120 located on the protrusion 230 side, so that the heating film 200 located on the transition part 210 side and the heating film 200 located on the protrusion 230 side can directly contact the side surface 110b and the bottom surface 110c to be heated, so that the heat conduction speed of the heated side surface 110b and the bottom surface 110c is faster than the heating speed of the main surface 110a. Since the battery cell 110 in this embodiment is in the shape of a cuboid, the shape of the opening 116 can be set to be rectangular.

[0068] In this embodiment, by setting openings 116 on the insulating film 120 located on one side of the transition portion 210 and the insulating film 120 located on one side of the protrusion 230, the heating film 200 located on one side of the transition portion 210 and the heating film 200 located on one side of the protrusion 230 can directly contact the side surface 110b and the bottom surface 110c to be heated, so that the heat conduction speed of the heated side surface 110b and the bottom surface 110c is faster than the heating speed of the main surface 110a, thereby reducing the possibility of temperature difference between the main surface 110a, the side surface 110b and the bottom surface 110c caused by the excessive heat dissipation speed of the side surface 110b and the bottom surface 110c, so as to ensure the uniformity of the heating film 200 when heating the battery module 100.

[0069] In a second aspect, the present application provides a battery system, which includes any one of the battery management systems provided in the first aspect and a battery module 100 , wherein the battery module 100 includes a plurality of battery cells 110 stacked sequentially along its length direction.

[0070] In some embodiments, the battery system further includes a box body, which is used to accommodate the battery thermal management system and the battery module 100, and the battery module 100 is connected to the inner wall of the box body through a fixing member.

[0071] Among them, the fixing part includes an adhesive layer, and the shell of the battery cell 110 and the box body are connected through the adhesive layer. The adhesive layer includes a structural adhesive layer. The material of the structural adhesive layer includes epoxy resin, etc. The epoxy resin has excellent adhesion, heat resistance and electrical insulation. It can tightly connect the box body and the battery module 100 while playing a good protective role in the operation of the battery module 100.

[0072] Specifically, the insulating film 120 on the surface of the battery cell 110 shell has poor adhesion to the structural adhesive layer. An opening 116 is provided in the insulating film on the surface of the battery cell 110 shell, so that the side surface of the battery cell 110 is exposed, so that the inner wall of the box can be directly bonded to the aluminum shell surface of the battery cell 110. The structural adhesive layer has good adhesion to the shell (generally an aluminum or steel shell), which increases the bonding strength between the box and the battery cell 110, thereby ensuring the tightness and reliability of the connection between the box and the battery cell 110 and the battery module 100.

[0073] In this embodiment, a box body is provided to help provide good protection for the battery module 100 and the battery thermal management system in the box body. The battery module 100 is tightly connected to the inner wall of the box body through the adhesive layer, which can ensure the stability of the battery system during the packaging operation.

[0074] The battery system of the present application can avoid direct contact between the shell and the heating film 200 by first wrapping a layer of insulating film 120 on the shell of the battery cell 110 and then wrapping the heating film 200, thereby reducing the risk of accidental electric shock or short circuit; and by providing openings 116 on the insulating film 120 located on one side of the transition portion 210 and the insulating film 120 located on one side of the protrusion 230, the heating film 200 located on one side of the transition portion 210 and the heating film 200 located on one side of the protrusion 230 can directly contact the side surface 110b and the bottom surface 110c to be heated, so that the heated The heat conduction speed of the hot side surface 110b and the bottom surface 110c is faster than the heating speed of the main surface 110a, thereby reducing the possibility of excessive heat dissipation of the side surface 110b and the bottom surface 110c causing a temperature difference between the main surface 110a, the side surface 110b and the bottom surface 110c, so as to ensure the uniformity of heating the battery module 100 by the heating film 200; and the provision of a box body facilitates the packaging operation of the battery system, and plays a good protective role for the battery module 100 and the battery thermal management system in the box body, so as to ensure the stability of the battery system during the packaging operation process.

[0075] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery thermal management system, applied to a battery module comprising a plurality of battery cells stacked in sequence, characterized in that: The battery thermal management system comprises: A heating film, comprising a plurality of foldable transition portions and non-transition portions sequentially arranged at intervals along its length direction, the heating film being used to be attached to a plurality of outer surfaces of the battery core; A first heating element is arranged in the non-transition portion; The second heating element is arranged in the transition part, and the second heating element and the first heating element are respectively used to heat the side that is in contact with the battery cell, wherein the breaking stress of the second heating element is greater than the breaking stress of the first heating element.

2. The battery thermal management system according to claim 1, characterized in that: It also includes a thermally conductive connector, which is located between the battery cell and the heating film. The thermally conductive connector adheres the transition portion to the outer surface of the battery cell on one side along its own width direction and the corner of the battery cell on one side in the width direction. The thermally conductive connector also adheres the non-transition portion to the outer surface of the battery cell on one side along its own length direction.

3. The battery thermal management system according to claim 2, characterized in that: The heat-conducting connector comprises a heat-conducting adhesive layer, and the thickness of the heat-conducting adhesive layer in the transition portion is greater than the thickness of the heat-conducting adhesive layer in the non-transition portion.

4. The battery thermal management system according to claim 1, characterized in that: The thickness of the transition portion is greater than the thickness of the non-transition portion.

5. The battery thermal management system according to claim 1, characterized in that: The area of ​​the fracture cross section of the second heating element is greater than the area of ​​the fracture cross section of the first heating element.

6. The battery thermal management system according to claim 1, characterized in that: The heating film further comprises a foldable protrusion, the protrusion is connected to the non-transition portion, the protrusion is folded to fit with the bottom surface of the battery core, and a third heating element is arranged in the protrusion.

7. The battery thermal management system according to claim 6, characterized in that: The fracture stress of the third heating element is not less than the fracture stress of the second heating element, and the heating power of the second heating element and / or the third heating element is greater than the heating power of the first heating element.

8. The battery thermal management system according to claim 1, characterized in that: The battery cell comprises a shell and an insulating film wrapping the shell, and openings are arranged on the insulating film located on the side surface and / or bottom surface of the battery cell.

9. A battery system, characterized in that: It comprises the battery thermal management system as described in any one of claims 1 to 8 and the battery module, wherein the battery module comprises a plurality of battery cells stacked sequentially along its length direction.

10. The battery system according to claim 9, characterized in that: The battery system further comprises a box body, wherein the box body is used to accommodate the battery thermal management system and the battery module, and the battery module is connected to the inner wall of the box body via a fixing member.

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