CN220290866U - Lithium battery - Google Patents

Abstract

The utility model relates to a lithium battery, which comprises a shell, a core package and a protective film, wherein a containing cavity is formed in the shell, the core package is arranged in the containing cavity, the protective film is wrapped on the outer surface of the core package, the protective film comprises a base material, the base material is provided with a first side surface attached to the core package and a second side surface opposite to the first side surface, a plurality of convex packages are arranged on the second side surface in a protruding mode, a detection device is arranged at one end, away from the base material, of at least part of the convex packages, and is positioned between the convex packages and the shell, and the detection device is used for detecting extrusion force between the protective film and the shell. The buffer effect of the protective film on the core bag prevents the core bag from shaking to cause abnormal deformation parameters detected by the detection device. Through with detection device and core package interval distance, reduce the heat influence of core package to detection device, and then improve the monitoring accuracy to the deformation parameter of core package. Therefore, the lithium battery has the characteristic of high monitoring accuracy of deformation parameters.

Description

Lithium battery

Technical Field

The utility model relates to the technical field of battery manufacturing, in particular to a lithium battery.

Background

The lithium battery is widely applied to equipment such as electric vehicles, communication base stations, emergency equipment and the like as energy storage equipment. A common square lithium battery mainly includes a square outer case, a core pack, and a protective film. The protective film is used for wrapping the outer surface of the core pack, the wrapped core pack is packaged into the shell, and electrolyte used for infiltrating the core pack is filled in the shell. In the charging and discharging process of the lithium battery, the core pack can generate respiratory effect, namely, the core pack is expanded and contracted. In the related art, a detection device such as a strain sensor, a pressure sensor, or the like is provided on the core pack. And monitoring the deformation parameters of the core bag in real time by using a detection device. When the deformation parameters detected by the detection device are different from the normal expansion and contraction rules of the core pack, the lithium battery can be subjected to intervention such as temperature reduction, flame retardance or pressure relief, so that the working performance of the lithium battery is ensured, and the service life of the lithium battery is prolonged.

The related art has the following disadvantages: in the charging and discharging process of the lithium battery, the core pack can generate a large amount of heat, and the heat of the core pack is transferred to the detection device positioned on the core pack. The detection device is susceptible to thermal deformation, so that the acquired deformation parameters are inaccurate, and even the lithium battery is wrongly interfered due to misjudgment of the detection device.

Disclosure of Invention

The utility model aims to provide a lithium battery which has high accuracy in monitoring deformation parameters of a core pack.

To achieve the purpose, the utility model adopts the following technical scheme:

the utility model provides a lithium battery, including shell, core package and protection film, have in the shell and hold the chamber, the core package set up in hold the intracavity, the protection film parcel is in the surface of core package, the protection film includes the substrate, the substrate has the laminating the first side of core package and with the second side that first side is dorsad mutually, the protrusion is provided with a plurality of convex hulls on the second side, at least part the convex hull deviates from the one end of substrate is provided with detection device, detection device is located between the convex hull with the shell, detection device is used for detecting the protection film with extrusion force between the shell.

Further, the first side face is provided with a groove, and the bottom of the groove extends into the convex hull.

Further, one end of the convex hull, which is away from the base material, or one end of the detection device, which is away from the base material, is provided with a mounting surface, and the mounting surface is parallel to the cavity wall of the accommodating cavity.

Further, the detection device is fixedly bonded with the convex hull.

Further, the end face of one end of the convex hull, which is away from the base material, is provided with a mounting groove, and at least part of the detection device is inserted into the mounting groove.

Further, the detection device is embedded in the convex hull.

Further, the base material comprises two first diaphragms, the core package is a square core package, the two first diaphragms are respectively wrapped on two largest side faces of the core package, and the convex hulls are arranged on the first diaphragms.

Further, on the same first membrane, the coverage rate of all the convex hulls on the first membrane is 40% -60%.

Further, along the height direction of the core package, the first membrane comprises an upper section, a middle section and a lower section which are sequentially connected from top to bottom, and the detection device is at least arranged on the convex hull positioned at the middle section; or alternatively, the first and second heat exchangers may be,

the first diaphragm comprises a first section, a second section and a third section which are sequentially connected along the length direction of the core package, and the detection device is at least arranged on the convex hull positioned on the second section; or alternatively, the first and second heat exchangers may be,

the detection device is at least arranged on the convex hull at the middle position of the first diaphragm.

Further, the detection device is a plurality of, and a plurality of detection devices are distributed on the first membrane at intervals.

Further, the convex hull is hemispherical, square, cuboid or trapezoidal.

Further, the shell is a cuboid structure, and the ratio of the length dimension to the height dimension of the shell is 6:5-2:1, wherein the ratio of the height dimension to the width dimension of the shell is 2:1-25:7.

compared with the prior art, the utility model has the beneficial effects that: through setting up the convex hull at the side of protection film towards the shell, detection device sets up in the one end that the convex hull deviates from the core package. The convex hulls can be used for filling gaps between the core hulls and the outer shells, so that abnormal deformation parameters detected by the detection device are avoided due to shaking of the core hulls. The convex hull makes the protection film have certain elasticity, when the core package takes place to rise and contract, plays the cushioning effect to the core package, and the extrusion force when avoiding the core package to rise and contract is concentrated relatively and leads to deformation parameter anomaly that detection device monitored. And through installing detection device in the one end that convex hull deviates from the core package for detection device and core package interval are apart from, reduce the heat influence of core package to detection device, and then improve the monitoring accuracy to the deformation parameter of core package. Therefore, the lithium battery has the characteristic of high monitoring accuracy of deformation parameters.

Drawings

Fig. 1 is an exploded view of a lithium battery according to an embodiment of the present utility model.

Fig. 2 is a cross-sectional view of a lithium battery according to an embodiment of the present utility model.

Fig. 3 is a partial cross-sectional view of a protective film according to an embodiment of the present utility model.

Fig. 4 is a partial cross-sectional view of a protective film according to another embodiment of the present utility model.

Fig. 5 is a schematic installation diagram of a protection film and a detection device according to an embodiment of the utility model.

Fig. 6 is a schematic installation diagram of a protection film and a detection device according to another embodiment of the utility model.

Fig. 7 is a schematic installation diagram of a protection film and a detection device according to another embodiment of the present utility model.

Fig. 8 is an expanded schematic view of a protective film according to an embodiment of the utility model.

Fig. 9 is an expanded schematic view of a protective film according to another embodiment of the present utility model.

In the figure:

1. a lower housing; 10. a receiving chamber; 2. a top cover; 3. a core pack; 4. a protective film; 41. a substrate; 411. a first membrane; 412. a second membrane; 413. a third membrane; 414. an upper section; 415. a middle section; 416. a lower section; 417. a first section; 418. a second section; 419. a third section; 42. convex hulls; 43. a groove; 44. a mounting surface; 45. a first side; 46. a second side; 5. and a detection device.

Detailed Description

In order to make the technical problems solved, the technical scheme adopted and the technical effects achieved by the utility model more clear, the technical scheme of the utility model is further described below by a specific embodiment in combination with the attached drawings.

As shown in fig. 1 and 2, the lithium battery provided by the utility model comprises a shell, a core pack 3 and a protective film 4. The shell is of a cuboid structure or a cylindrical structure, and when the lithium battery is a square battery, the shell is of a cuboid structure correspondingly; when the lithium battery is a cylindrical battery, the housing is correspondingly in a cylindrical structure. The shell comprises a lower shell 1 and a top cover 2, wherein the top cover 2 is welded and fixed with the opening end of the lower shell 1, and a closed accommodating cavity 10 is formed between the top cover 2 and the lower shell 1. The core pack 3 is used for storing electric energy, the top cover 2 is provided with a pole used for circuit connection, the core pack 3 is provided with a pole lug, and the core pack 3 is electrically connected with the pole lug through the pole lug. The protective film 4 wraps the outer surface of the core pack 3, and the core pack 3 and the protective film 4 are accommodated in the accommodating cavity 10 together. The protective film 4 has the shaping and protecting effects on the core pack 3, and can prevent the core pack 3 from being damaged when being put into the lower shell 1 in the production process.

The lithium battery in this embodiment will be described in detail by taking a square battery as an example, and when the lithium battery is normally placed, the top cover 2 is located at the top position of the lithium battery. That is, the X direction is shown as the longitudinal direction of the lithium battery, the Y direction is shown as the thickness direction of the lithium battery, and the Z direction is shown as the height direction of the lithium battery.

Referring to fig. 2 and 3, the protective film 4 includes a base material 41 and a convex hull 42. The base material 41 is a planar film structure, the base material 41 is a main body structure of the protective film 4, and the base material 41 is used for wrapping the outer surface of the core pack 3. The base material 41 has a first side 45 attached to the core pack 3 and a second side 46 opposite to the first side 45. I.e. the first side 45 faces the core pack 3 and the second side 46 faces the outer shell. The convex hulls 42 are plural, and the convex hulls 42 are disposed on the second side 46 of the base 41.

The lithium battery further comprises a detection device 5, the detection device 5 is arranged at one end, deviating from the base material 41, of the convex hull 42, the detection device 5 is arranged between the convex hull 42 and the shell, and the detection device 5 can detect extrusion force between the protective film 4 and the shell. In specific application, the detection devices 5 can be installed on part of the convex hulls 42, or the detection devices 5 can be installed on all the convex hulls 42, and the number of the detection devices 5 can be reasonably selected according to specific monitoring positions and monitoring ranges. The detection device 5 is in the prior art, the detection device 5 is a pressure sensing piece, when the core pack 3 is expanded due to the expansion and shrinkage of the respiratory effect or the internal air pressure of the lithium battery is increased due to the short circuit accident, the core pack 3 extrudes the detection device 5 through the protection film 4, and then the corresponding extrusion force is obtained according to the resistance change of the pressure sensing piece. The specific working state of the lithium battery can be judged by acquiring monitoring data of the internal extrusion force of the lithium battery and combining the expansion and contraction rule of the core pack 3 during normal respiration effect so as to accurately intervene in the lithium battery. For example, when the monitoring data shows that the extrusion force change rule of the lithium battery is different from the expansion rule in normal respiratory effect, the lithium battery can be subjected to cooling intervention, pressure relief intervention and the like so as to avoid serious fire and explosion accidents of the lithium battery.

It will be appreciated that for ease of lithium battery production, the dimensions of the core pack 3 are slightly smaller than the dimensions of the receiving cavity 10 within the outer casing, such that there is a gap between the core pack 3 and the cavity walls of the receiving cavity 10. Through setting up convex hull 42 on substrate 41, convex hull 42 is located the clearance between substrate 41 and the lower casing 1, and usable convex hull 42 supports core package 3 tightly in holding chamber 10, avoids core package 3 taking place to rock in holding chamber 10, and then avoids core package 3 to arouse the mistake intervention because of rocking extrusion detection device 5. Due to the convex hull 42, the protection film 4 has better elasticity, and when the core hull 3 is expanded and contracted due to charge and discharge, the convex hull 42 can play a role in buffering, so that abnormal deformation parameters monitored by the detection device 5 due to relative concentration of extrusion force of the core hull 3 are avoided. Meanwhile, the detection device 5 is arranged at one end of the convex hull 42, which is away from the base material 41, so that the detection device 5 and the core package 3 are separated by a certain distance, the thermal influence of the core package 3 on the detection device 5 is reduced, and the accuracy of monitoring the deformation parameters of the core package 3 is improved.

Alternatively, the detecting means 5 is in the form of a sheet, and the detecting means 5 includes a resistance strain gauge made of a metal foil or a semiconductor sheet, and when the resistance strain gauge is mechanically deformed, the resistance value is changed accordingly. The detection device 5 is installed in the convex hull 42 one end that deviates from substrate 41, and detection device 5 supports and holds on the chamber wall in chamber 10, and when core package 3 took place to bulge, core package 3 extrudeed detection device 5 through protection film 4, through the processing to the extrusion force in order to obtain the deformation parameter of core package 3.

Optionally, referring to fig. 3, the first side 45 of the substrate 41 is provided with a groove 43, and the bottom of the groove 43 extends into the convex hull 42. It can also be understood that the convex hull 42 is of a cavity structure, so that the convex hull 42 has good elasticity, and the buffering effect of the protective film 4 on the core hull 3 during expansion and contraction is improved. And by arranging the convex hull 42 to be of a cavity structure, the heat insulation effect of the convex hull is improved, and heat conduction of the core package 3 to the detection device 5 is further reduced. The base material 41 and the convex hull 42 are of unitary construction. The grooves 43 penetrate through the base material 41 and extend into the convex hull 42, and the structure can be pressed on the base material 41 by a die to form the convex hull 42, so that the protective film 4 can be easily manufactured and processed.

Alternatively, as shown with reference to fig. 3 and 4, the convex hull 42 may be hemispherical, square, rectangular, trapezoidal, cylindrical, or pyramidal. The convex hull 42 has the function of filling the gap between the base material 41 and the cavity wall of the accommodating cavity 10 with its convex structure, and making the entire protective film 4 have good elasticity, thereby playing a role of buffering the core pack 3. Therefore, the shape of the convex hull 42 is not particularly limited in this embodiment, and the shape of the convex hull 42 may be an irregular polygon. All the convex hulls 42 on the protective film 4 may be the same shape, for example, as shown in fig. 2, all the convex hulls 42 on the protective film 4 are hemispherical. All the convex hulls 42 on the protective film 4 may also be in the shape of a plurality of combinations of hemispheres, cubes, cuboids, terraces, cylinders or cones. For example, all the convex hulls 42 on the protective film 4 are combined by two shapes, wherein one part of the convex hulls 42 is hemispherical in shape and the other part of the convex hulls 42 is trapezoidal in shape.

Alternatively, referring to fig. 5, the detecting device 5 is adhesively fixed to the end of the convex hull 42 facing away from the base material 41. The side of the detection device 5 facing the housing is a mounting surface 44, the mounting surface 44 being parallel to the cavity wall of the receiving cavity 10. A side surface of the detecting device 5 facing away from the mounting surface 44 is fixed to an end surface of the convex hull 42 by adhesion. Specifically, the detection device 5 and the convex hull 42 are adhered and fixed by double faced adhesive tape or adhesive. When the core pack 3 bulges, the core pack 3 presses the detecting device 5 through the protective film 4, and the mounting surface 44 of the detecting device 5 is abutted against the cavity wall of the accommodating cavity 10, so that the detecting device 5 obtains a corresponding pressing force.

Alternatively, referring to fig. 6, one end of the convex hull 42 facing away from the base material 41 is provided with a mounting groove, the notch of which faces the cavity wall of the accommodating cavity 10, and the groove bottom of which is parallel to the cavity wall of the accommodating cavity 10. The detection device 5 is inserted into the mounting groove, and the groove bottom and the groove wall of the mounting groove are adhered and fixed with the detection device 5. The detection device 5 is inserted into the mounting groove and is adhered to the inner wall of the mounting groove, so that the contact surface between the detection device 5 and the convex hull 42 is increased, and the detection device 5 and the convex hull are firmly adhered. In a specific implementation, the detection device 5 may be partially or fully inserted into the mounting groove. The side of the detection device 5 facing the housing is a mounting surface 44, the mounting surface 44 being parallel to the cavity wall of the receiving cavity 10. When the core pack 3 bulges, the core pack 3 presses the detecting device 5 through the protective film 4, and the mounting surface 44 of the detecting device 5 is abutted against the cavity wall of the accommodating cavity 10, so that the detecting device 5 obtains a corresponding pressing force.

Alternatively, referring to fig. 7, the detection device 5 is embedded within the convex hull 42. By embedding the detection device 5 in the convex hull 42, the electrolyte in the accommodating cavity 10 can be prevented from affecting the detection device 5. The side of the convex hull 42 facing away from the base material 41 is a mounting surface 44, and the mounting surface 44 is parallel to the cavity wall of the accommodating cavity 10. When the core pack 3 bulges, the core pack 3 presses the detection device 5 through the protective film 4, and the mounting surface 44 of the convex pack 42 abuts against the cavity wall of the accommodating cavity 10, so that the detection device 5 obtains a corresponding pressing force.

The detection device 5 detects that the convex hull 42 and the housing need to be pressed against each other. When the detecting means 5 communicates with the outside of the convex hull 42, the detecting means 5 can directly abut against the cavity wall of the accommodating cavity 10, and therefore, the mounting surface 44 for interfacing with the housing is located on the detecting means 5. When the detecting device 5 is embedded in the convex hull 42, one end of the convex hull 42 facing away from the base material 41 directly abuts against the cavity wall of the accommodating cavity 10, and therefore, the mounting surface 44 for interfacing with the housing is located on the convex hull 42.

Alternatively, referring to fig. 1 and 8, the base material 41 is a main body structure of the protective film 4, the base material 41 is wrapped on the outer surface of the core pack 3, and the shape of the base material 41 matches the shape of the core pack 3. The substrate 41 is developed and then has the structure shown in fig. 8. In this embodiment, the lithium battery is a square battery, and correspondingly, the core pack 3 is a square core pack, that is, the outer shell and the core pack 3 are both in a cuboid structure. The areas of the two side surfaces in the thickness direction (Y direction in the drawing) of the core pack 3 are the largest, that is, the two large surfaces of the core pack 3. Of the two sides in the height direction (Z direction in the drawing) of the core pack 3, one side facing the top cover 2 is a top surface, and the other side facing away from the top cover 2 is a bottom surface. The substrate 41 includes a first membrane 411, a second membrane 412, and a third membrane 413. The two first films 411 are respectively wrapped on two largest sides of the core pack 3, namely, the two first films 411 are used for wrapping two large sides of the core pack 3. Since the top surface of the core pack 3 is provided with the tab and the tab is connected with the top cover 2, the top surface of the core pack 3 is not covered with the protective film 4. The second membrane 412 is located between the two first membranes 411, and the second membrane 412 is used to cover the bottom surface of the core pack 3. The number of the third films 413 is at least two, and the two third films 413 are respectively used for wrapping two side surfaces of the core pack 3 in the length direction (X direction in the drawing). To ensure the stability of the wrapping of the protective film 4 on the core pack 3, four third diaphragms 413 may also be provided, i.e. the opposite sides of each first diaphragm 411 are provided with third diaphragms 413.

The convex hull 42 is provided on the first diaphragm 411. It will be appreciated that the areas of the protective film 4 having the convex hulls 42 are relatively more elastic and the areas of the protective film 4 not provided with the convex hulls 42 are relatively less elastic. The convex hull 42 is arranged on the first diaphragm 411 with the largest area, so that the expansion and contraction buffer effect on the core hull 3 can be achieved, other side surfaces except for two large surfaces of the core hull 3 are tightly wrapped by the protective film 4, the protective film 4 has enough extrusion force on the core hull 3, and the shaping and protecting effects on the core hull 3 are achieved.

Along the height direction of the core pack 3, the first membrane 411 includes an upper section 414, a middle section 415, and a lower section 416 connected in sequence from top to bottom, and the areas of the upper section 414, the middle section 415, and the lower section 416 are the same. Wherein the upper section 414 is adjacent to the top surface of the core pack 3 and the lower section 416 is adjacent to the bottom surface of the core pack 3. A plurality of convex hulls 42 are provided on each of the upper section 414, the middle section 415, and the lower section 416. The detection device 5 is arranged on the convex hull 42 at the middle section 415. The number of the detecting devices 5 is plural, and the detecting devices 5 are distributed on the middle section 415 at intervals. It can be understood that the plurality of detection devices 5 are arranged, so that a plurality of positions on the large surface of the core pack 3 can be monitored, and the expansion and contraction of the core pack 3 can be monitored more comprehensively and accurately in real time. Meanwhile, the most obvious area of the core pack 3 is located in the middle of the core pack 3, so that the detection device 5 is arranged on the middle section 415 of the first diaphragm 411, which is beneficial to reducing the arrangement quantity of the detection device 5 and saving the cost. Of course, in other embodiments, a plurality of detecting devices 5 may be uniformly arranged on the entire first diaphragm 411.

In another embodiment, referring to fig. 9, the first membrane 411 includes a first section 417, a second section 418, and a third section 419 connected in sequence along the length direction of the core pack 3, and the first section 417, the second section 418, and the third section 419 have the same area. A plurality of convex hulls 42 are provided on each of the first section 417, the second section 418, and the third section 419. The detection means 5 are arranged on the convex hull 42 at the second section 418. A plurality of detection devices 5 are spaced apart on the second section 418. It can be understood that the plurality of detection devices 5 are arranged, so that a plurality of positions on the large surface of the core pack 3 can be monitored, and the expansion and contraction of the core pack 3 can be monitored more comprehensively and accurately in real time. Meanwhile, the most obvious area of the core pack 3 is located in the middle of the core pack 3, so that the detection devices 5 are arranged on the second section 418 of the first diaphragm 411, the arrangement quantity of the detection devices 5 is reduced, and the cost is saved. Of course, in other embodiments, a plurality of detecting devices 5 may be uniformly arranged on the entire first diaphragm 411.

In yet another embodiment, the first diaphragm 411 includes a central position, i.e., in the geometric center and surrounding area of the first diaphragm 411, and a peripheral position, i.e., in the peripheral portion of the first diaphragm 411. A plurality of detecting means 5 are provided at intervals on the convex hull 42 at the middle position of the first diaphragm 411. The most obvious area of the core pack 3 is located at the middle position of the core pack 3, so that the detection devices 5 are arranged on the second section 418 of the first diaphragm 411, which is beneficial to reducing the arrangement quantity of the detection devices 5 and saving the cost. Of course, in other embodiments, a plurality of detecting devices 5 may be uniformly arranged on the entire first diaphragm 411.

Alternatively, on the same first membrane 411, the coverage of all the convex hulls 42 on the first membrane 411 is 40% -60%. The coverage rate of the convex hull 42 on the first membrane 411 is reasonably selected, so that the protective film 4 has certain elasticity, and the buffering effect on the core hull 3 is achieved. Meanwhile, the protection film 4 plays a certain extrusion force on the core bag 3 so as to play a role in shaping and protecting the core bag 3.

Optionally, the casing is a cuboid structure, and the length, width and height of the casing all correspond to the length, width and height of the lithium battery. The ratio of the length dimension to the height dimension of the housing is 6:5-2:1, a step of; the ratio of the height dimension to the width dimension of the housing is 2:1-25:7. the length dimension of the housing is 300-400mm, and the length dimension of the housing includes, but is not limited to, 300mm, 310mm, 320mm, 330mm, 340mm, 350mm, 360mm, 370mm, 380mm, 390mm, 400mm. The width dimension of the housing is 70-100mm, including but not limited to 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm. The height dimension of the housing is 200-250mm, including but not limited to 200mm, 215mm, 220mm, 225mm, 230mm, 235mm, 240mm, 245mm, 250mm. It will be appreciated that the length to height ratio of the housing is set at 6:5-2:1, the lithium battery has a larger large surface (the large surface is two opposite side surfaces in the width direction of the shell), which is beneficial to promoting the heat dissipation of the lithium battery. Under the aspect ratio of the length to the width, the shell makes the inner space of the accommodating cavity 10 more reasonable, is beneficial to improving the utilization rate of the active substances in the inner space, further achieves the purpose of prolonging the service cycle of the lithium battery, and meets the requirements of users on over-endurance and over-capacity.

The remarkable effect of this embodiment is: by providing the bulge 42 on the side of the protective film 4 facing the housing, the detection device 5 is arranged at the end of the bulge 42 facing away from the core wrap 3. The convex hull 42 can be used to fill the gap between the core pack 3 and the outer shell, so as to avoid abnormal deformation parameters detected by the detection device 5 due to shaking of the core pack 3. The convex hull 42 enables the protective film 4 to have certain elasticity, and when the core package 3 is expanded and contracted, the buffer effect on the core package 3 is achieved, and abnormal deformation parameters monitored by the detection device 5 due to the fact that extrusion force of the core package 3 during expansion and contraction is relatively concentrated is avoided. And through installing detection device 5 in the one end that convex hull 42 deviates from core package 3 for detection device 5 and core package 3 interval certain distance reduce the heat influence of core package 3 to detection device 5, and then improve the monitoring accuracy to the deformation parameter of core package 3. Therefore, the lithium battery has the characteristic of high monitoring accuracy of deformation parameters.

The foregoing is merely exemplary of the present utility model, and those skilled in the art should not be considered as limiting the utility model, since modifications may be made in the specific embodiments and application scope of the utility model in light of the teachings of the present utility model.

Claims (12)

1. The utility model provides a lithium battery, includes shell, core package and protection film, have in the shell and hold the chamber, the core package set up in hold the intracavity, the protection film parcel is in the surface of core package, its characterized in that, the protection film includes the substrate, the substrate has the laminating the first side of core package and with the second side that first side is on the back mutually, the protrusion is provided with a plurality of convex hulls on the second side, at least part the convex hull deviates from the one end of substrate is provided with detection device, detection device is located between the convex hull with the shell, detection device is used for detecting the protection film with extrusion force between the shell.

2. The lithium battery of claim 1, wherein the first side is grooved, and a bottom of the groove extends into the convex hull.

3. The lithium battery according to claim 1, wherein one end of the convex hull facing away from the base material or one end of the detection device facing away from the base material is provided with a mounting surface, and the mounting surface is parallel to a cavity wall of the accommodating cavity.

4. The lithium battery of claim 1, wherein the detection device is adhesively secured to the convex hull.

5. The lithium battery of claim 4, wherein an end surface of the convex hull, which is away from one end of the base material, is provided with a mounting groove, and at least part of the detection device is inserted into the mounting groove.

6. The lithium battery of claim 1, wherein the detection device is embedded within the convex hull.

7. The lithium battery of any one of claims 1-6, wherein the substrate comprises two first membranes, the core pack is a square core pack, the two first membranes are respectively wrapped on two largest sides of the core pack, and the convex hulls are disposed on the first membranes.

8. The lithium battery of claim 7, wherein the coverage of all of the convex hulls on the first membrane is 40% -60% on the same first membrane.

9. The lithium battery according to claim 7, wherein the first membrane comprises an upper section, a middle section and a lower section which are connected in sequence from top to bottom along the height direction of the core pack, and the detection device is at least arranged on the convex hull located at the middle section; or alternatively, the first and second heat exchangers may be,

the first diaphragm comprises a first section, a second section and a third section which are sequentially connected along the length direction of the core package, and the detection device is at least arranged on the convex hull positioned on the second section; or alternatively, the first and second heat exchangers may be,

the detection device is at least arranged on the convex hull at the middle position of the first diaphragm.

10. The lithium battery of claim 9, wherein the plurality of detection devices are spaced apart on the first membrane.

11. The lithium battery of any one of claims 1 to 6, wherein the convex hull is hemispherical, square, rectangular or trapezoidal.

12. The lithium battery of any one of claims 1 to 6, wherein the housing has a rectangular parallelepiped structure, and a ratio of a length dimension to a height dimension of the housing is 6:5-2:1, wherein the ratio of the height dimension to the width dimension of the shell is 2:1-25:7.