Battery pack and electric system

Abstract

A battery pack (10) and an electric system. The battery pack (10) comprises: a plurality of battery cells (110) arranged in the thickness direction of the battery cells (110); limiting members (200) abutting against the end portions of a battery module (100) in the thickness direction of the battery cells (110), first slots (222) extending in the thickness direction of the battery cells (110) being formed in each limiting member; and a first tightening strap (300) cooperating with the first slots (222), the first tightening strap (300) surrounding the battery module (100) and being sleeved on the limiting members (200) in the height direction of the battery cells (110).

Description

Battery pack and power system

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 2023107585960 filed with the State Intellectual Property Office of China on June 26, 2023, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the field of new energy technology, and in particular to a battery pack and a power system. Background Art

[0004] As an important energy storage device, battery packs are widely used in the new energy field. Traditional battery packs often have related components that become loose or even fall off, affecting the reliability of the battery pack.

[0005] Summary of the Invention

[0006] One of the technical problems addressed by this application is how to improve the reliability of battery pack operation.

[0007] A battery pack, a battery module, comprises a plurality of battery cells, wherein the battery cells are arranged along the thickness direction of the battery cells;

[0008] a limiting member abutting against an end portion of the battery module in the thickness direction of the battery cell, wherein the limiting member is provided with a first groove extending in the thickness direction of the battery cell; and

[0009] A first tightening band is arranged around the battery module and sleeved on the limiting member along the height direction of the battery core, and the first tightening band is matched with the first groove.

[0010] In one embodiment, the limiting member includes a main body, a basic convex rib and a first convex rib, the first tightening band is sleeved on the main body, the main body has a side surface extending along the thickness direction of the battery cell, the basic convex rib and the first convex rib are spaced apart along the height direction of the battery module and protrude on the side surface, the first convex rib is closer to the upper cover of the battery cell in the battery module relative to the basic convex rib, and the first groove is formed between the basic convex rib and the first convex rib.

[0011] In one embodiment, the first rib extends from one end of the first rib away from the base rib to one end of the side surface close to the upper cover.

[0012] In one embodiment, the first rib has a guiding slope, and the distance from the guiding slope to the side surface gradually increases along the installation direction of the first tightening band.

[0013] In one embodiment, the angle between the guide slope and the side surface ranges from 2° to 10°.

[0014] In one embodiment, the maximum distance from the guide slope to the side surface is 0.5 mm to 1 mm.

[0015] In one embodiment, there is a first distance between two sections of the first tightening band extending in the thickness direction of the battery core, and there is a second distance between two guide inclined surfaces arranged opposite to each other on the same limiting member, and the first distance is smaller than the second distance.

[0016] In one embodiment, the basic rib has a convex surface, and the distance from the convex surface to the side surface remains constant, and the distance from the convex surface to the side surface ranges from 1 mm to 3 mm.

[0017] In one embodiment, the distance from the protruding surface to the side surface is greater than the thickness of the first tightening band, and the difference between the distance from the protruding surface to the side surface and the thickness of the first tightening band is greater than half the thickness of the first tightening band.

[0018] In one embodiment, the first tightening strap includes a strap body and an insulating sleeve, the strap body is made of steel and includes a first section and a second section connected to each other, the first section is sleeved on the main body, the second section is located outside the main body and corresponds to the battery module, and the insulating sleeve is made of flexible material and sleeved on the second section.

[0019] In one embodiment, the first section further includes an embedding portion that cooperates with the first groove, and the insulating sleeve is sleeved on at least a portion of the embedding portion.

[0020] In one embodiment, the width of the first tightening band is greater than or equal to the width of the first groove.

[0021] In one embodiment, the main body further has an end surface extending perpendicular to the thickness direction of the battery core, the first tightening band is sleeved on the end surface, and a countersunk hole is opened on the end surface.

[0022] In one embodiment, the main body has an end surface extending perpendicular to the thickness direction of the battery cell, the end surface and the side surface are equal in size in the height direction of the battery module, and the area of ​​the end surface is larger than the area of ​​the side surface.

[0023] An electric power system comprises the battery pack described above.

[0024] A technical effect of an embodiment of the present application is: given that the first groove extends along the thickness direction of the battery cell, when the thickness direction of the battery cell is the length direction of the battery module, when the first tightening strap cooperates with the first groove, even if the length of the battery module becomes smaller and the limiting member moves away from the first tightening strap, the width dimension of the battery module will remain unchanged, so that the first tightening strap cannot escape from the first groove and slide off the limiting member. The first tightening strap will always cooperate with the first groove, ensuring that the first tightening strap can continue to perform the bundling function, avoiding the first tightening strap from being separated from the limiting member and affecting the normal operation of the battery pack, thereby improving the reliability of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0027] FIG1 is a schematic diagram of a partial three-dimensional structure of a battery pack provided in one embodiment.

[0028] FIG2 is a schematic diagram of a partial exploded structure of the battery pack shown in FIG1 .

[0029] FIG3 is a schematic diagram of the three-dimensional structure of the limiting component in the battery pack shown in FIG1 .

[0030] FIG4 is a schematic diagram of the planar structure of the position limiting member in the battery pack shown in FIG1 .

[0031] FIG5 is a schematic perspective cross-sectional view of the first tightening strap in the battery pack shown in FIG1 . DETAILED DESCRIPTION

[0032] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that if 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", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0034] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0035] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0036] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] It should be noted that if 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 an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0038] Referring to Figures 1, 2, and 3, a battery pack 10 provided in one embodiment of the present application includes a battery module 100, a retaining member 200, and a first tightening band 300. The retaining member 200 abuts against the lengthwise end of the battery module 100, and the first tightening band 300 surrounds the battery module 100 and fits over the retaining member 200. As shown in Figure 1, the length of the battery module 100 is the X-axis, the width of the battery module 100 is the Y-axis, and the height of the battery module 100 is the Z-axis.

[0039] Referring to Figures 1, 2, and 3, in some embodiments, a battery module 100 includes a plurality of battery cells 110, which are arranged along the thickness direction of the battery cells 110. The thickness direction of the battery cells 110 is also the length direction of the battery module 100. The battery cells 110 have a top cover 111, which is used to pass the electrodes of the battery cells 110. During the arrangement of the battery cells 110, the top covers 111 of all the battery cells 110 are located on the same side of the height direction of the battery module 100. There can be two stoppers 200, each located on either side of the length direction of the battery module 100, so that the two stoppers 200 respectively abut against the two ends of the length direction of the battery module 100, thereby sandwiching the entire battery module 100 between the two stoppers 200. The first tightening band 300 has a closed-loop structure. Since the first tightening band 300 is arranged around the battery module 100 and is fitted onto the retaining member 200, the first tightening band 300 applies a tightening force to the two retaining members 200, and the two retaining members 200 apply a clamping force to the battery module 100. During the fitting process, the first tightening band 300 fits over the retaining member 200 along the height direction of the battery cell 110. Therefore, the first tightening band 300 can bind the battery module 100 and the retaining member 200, thereby forming a bundled whole. The battery pack 10 may also include a housing, and the bundled whole can be placed in the housing to facilitate assembly of the entire battery pack 10. For the above-mentioned bundling as a whole, it is usually necessary to allow a certain gap to exist between the battery cells 110 in the battery module 100, so as to provide a certain escape space for the expansion of the battery cells 110 during the cycle, and to avoid the limiting parts exerting a large binding force on the battery cells 110 during the cycle of the battery cells 110, thereby affecting the cycle performance of the battery.

[0040] 1 , 3 , and 4 , in some embodiments, the retaining member 200 may include a main body 210, a first rib 220, and a base rib 230. The main body 210 may be a generally rectangular plate-like structure, having an end face 211, a side face 212, and an abutting face 213. The end face 211 and the abutting face 213 may both extend along the width of the battery module 100 and be spaced apart along the length of the battery module 100. The side face 212 may extend along the length of the battery module 100 and be connected between the end face 211 and the abutting face 213. Both the end face 211 and the abutting face 213 may be disposed at an angle to the side face 212, for example, at a 90° angle. The abutment surface 213 directly abuts the longitudinal end of the battery module 100, and the first tightening band 300 is fitted over the end surface 211 and the side surface 212. When the abutment surface 213 abuts the battery module 100, the side surface 212 can be flush with the width of the battery module 100. The dimensions of the end surface 211, side surface 212, and abutment surface 213 along the height of the battery module 100 can be the same, and the combined areas of the end surface 211 and abutment surface 213 can be significantly larger than the area of ​​the side surface 212.

[0041] Referring to Figures 1, 3, and 4, in some embodiments, the first rib 220 and the base rib 230 can extend along the height of the battery module 100, such that the first rib 220 and the base rib 230 are aligned. Both the first rib 220 and the base rib 230 are projecting from the side surface 212, such that both protrude a certain height relative to the side surface 212. The first rib 220 is closer to the top cover 111 of the battery cell 110 than the base rib 230, which can be understood as the first rib 220 being positioned above the base rib 230. The first rib 220 and the base rib 230 are spaced apart, with the gap between them forming a first groove 222. This can be understood as the base rib 230, the first rib 220, and the side surface 212 collectively forming the first groove 222. Obviously, the first groove 222 extends a certain length along the length of the battery module 100. When the first tightening band 300 is mounted on the main body 210, the first tightening band 300 will engage with the first groove 222, which will effectively limit the first tightening band 300 and improve the installation accuracy of the first tightening band 300.

[0042] If a groove is provided on the end face 211 of the main body 210, the groove extends along the width direction of the battery module 100, and the tightening band cooperates with the groove. Due to the certain gap between the battery cells 110 in the bundled battery module, when the battery cells 110 are brought closer to each other and the gap is reduced, the length of the battery module 100 will become smaller, and the two limiters 200 can be brought closer to each other and the distance between them will be reduced. Therefore, when the two limiters 200 are close to each other, since the length of the tightening band remains constant, the tightening band will be separated from the groove and slide off the limiter 200, which will affect the normal operation of the battery pack 10, thereby affecting the reliability of the battery pack 10. In addition, the extended length of the groove on the end face 211 is relatively large, which will increase the processing cost of the groove, thereby increasing the manufacturing cost of the battery pack 10.

[0043] In the battery pack 10 of the aforementioned embodiment, since the first groove 222 extends along the length of the battery module 100, and the first tightening strap 300 cooperates with the first groove 222, even if the battery module 100 decreases in length, causing the two retaining members 200 to approach each other, the width of the battery module 100 remains unchanged. This prevents the first tightening strap 300 from disengaging from the first groove 222 and sliding off the retaining member 200. The first tightening strap 300 remains engaged with the first groove 222, ensuring that the first tightening strap 300 can continue to perform its binding function and preventing the first tightening strap 300 from disengaging from the retaining member 200 and affecting the normal operation of the battery pack 10, thereby improving the reliability of the battery pack 10. Furthermore, since the area of ​​the side surface 212 is smaller than that of the end surface 211, the width of the first groove 222 is relatively small, thereby reducing the processing cost of the first groove 222 and ultimately reducing the manufacturing cost of the entire battery pack 10. It can be understood that, in view of the special structure inside the battery cell 110 , the width dimension of the battery cell 110 can remain unchanged during the cycle of the battery cell 110 , so that the width dimension of the entire battery module 100 remains unchanged.

[0044] Referring to Figures 1, 3, and 4, in some embodiments, the first rib 220 extends from one end of the first rib 220 away from the base rib 230 to the end of the side surface 212 near the upper cover 111. This can be understood as the upper end of the first rib 220 being flush with the upper end of the side surface 212. The first rib 220 has a guide slope 221. The distance from the guide slope 221 to the side surface 212 gradually increases from the end of the guide slope 221 away from the base rib 230 to the end near the base rib 230, or from the upper end to the lower end of the guide slope 221, or along the installation direction of the first tightening strap 300. During installation of the first tightening strap 300, the first tightening strap 300 can be first placed on the guide bevel 221. Then, downward pressure is applied to the first tightening strap 300, causing it to slide downward along the guide bevel 221 into the first groove 222, thereby engaging with the first groove 222 and completing installation of the first tightening strap 300. The angle α between the guide bevel 221 and the side surface 212 ranges from 2° to 10°. For example, the angle can be 2°, 5°, or 10°. The distance A between the end of the guide bevel 221 closest to the base rib 230 and the side surface 212 ranges from 0.5 mm to 1 mm. This means that the distance from the lower end of the guide bevel 221 to the side surface 212 is from 0.5 mm to 1 mm. Alternatively, the maximum distance between the guide bevel 221 and the side surface 212 is from 0.5 mm to 1 mm. For example, the distance between the lower end of the guide slope 221 and the side surface 212 can be 0.5 mm, 0.5 mm, or 1 mm. Due to the above-described configuration of the guide slope 221, the guide slope 221 can have a good guiding function, facilitating smooth engagement of the first tightening band 300 with the first groove 222, thereby improving installation efficiency of the first groove 222.

[0045] 4 and 5 , the distance between the two sections of the first tightening band 300 extending along the length of the battery module 100 is denoted as a first distance d. The first distance d can be understood as the distance between the inner surfaces of the two sections extending along the length of the battery module 100. The distance between the two opposing guide slopes 221 on the same stopper 200 is denoted as a second distance D. The first distance d is smaller than the second distance D. Therefore, as the first tightening band 300 slides down the guide slopes 221, the first tightening band 300 exerts pressure on the guide slopes 221. When the first tightening band 300 engages with the first groove 222, the first rib 220 exerts a blocking force on the first tightening band 300, preventing the first tightening band 300 from passing over the first rib 220 and disengaging from the first groove 222.

[0046] Referring to Figures 1, 3, and 4, in some embodiments, the base rib 230 has a protruding surface 231. The distance B between the protruding surface 231 and the side surface 212 remains constant, making the base rib 230 roughly rectangular. The distance B between the protruding surface 231 and the side surface 212 ranges from 1 mm to 3 mm. For example, the distance B between the protruding surface 231 and the side surface 212 can be 1 mm, 2 mm, or 3 mm. The distance between the protruding surface 231 and the side surface 212 can be understood as the protrusion height of the base rib 230 relative to the side surface 212. The distance between the protruding surface 231 and the side surface 212 is greater than the thickness of the first tightening band 300, and the difference between the distance between the protruding surface 231 and the side surface 212 and the thickness of the first tightening band 300 is greater than half the thickness of the first tightening band 300. When the first tightening strap 300 is engaged with the first groove 222, the surface of the first tightening strap 300 away from the side surface 212 in the thickness direction cannot be flush with the protruding surface 231. As a result, the surface of the first tightening strap 300 away from the side surface 212 in the thickness direction is located within the first groove 222 and is separated from the protruding surface 231 by a certain distance. This makes it more difficult for the first tightening strap 300 to pass over the protruding surface 231 and escape from the first groove 222, further improving the reliability of the battery pack 10.

[0047] Referring to Figures 1, 2, and 5, in some embodiments, the first tightening strap 300 includes a strap body 310 and an insulating sleeve 320. The strap body 310 is made of steel, while the insulating sleeve 320 is made of a flexible material with insulating properties. The strap body 310 includes a first section 311 and a second section 312 that are interconnected. The first section 311 is mounted on the main body 210. The remaining portion of the strap body 310, excluding the first section 311, forms the second section 312. The second section 312 is located outside the main body 210 and corresponds to the battery module 100. The insulating sleeve 320 is mounted on the second section 312. The insulating sleeve 320 is mounted on the second section 312, effectively preventing the second section 312 from contacting the battery cells 110 within the battery module 100 and causing a short circuit.

[0048] In some embodiments, the first section 311 further includes an embedding portion 3111 that engages with the first groove 222, and the insulating sleeve 320 is sleeved over at least a portion of the embedding portion 3111. By sleeved over at least a portion of the embedding portion 3111, the insulating sleeve 320 is made of a flexible material and is easily compressed, making it easier to slide the first tightening strap 300 downward along the guide slope 221 into the first groove 222. As the first tightening strap 300 slides downward along the guide slope 221 and engages with the first groove 222, the insulating sleeve 320 comes into direct contact with the guide slope 221. This effectively prevents the embedding portion 3111 (which has a greater hardness) from generating significant friction with the guide slope 221, thereby preventing metal debris generated by the friction from accumulating within the battery pack 10 and creating electrical conduction with the battery module 100, thereby posing a safety risk.

[0049] In some embodiments, a countersunk hole 2111 is formed on the end surface 211 of the main body 210. The number of countersunk holes 2111 can be multiple. The countersunk holes 2111 can apply force to the bundled assembly formed by the first tightening strap 300, the battery module 100, and the retaining member 200 to facilitate transportation of the bundled assembly. The width of the first tightening strap 300 can be greater than or equal to the width of the first groove 222, so that the first tightening strap 300 is tightly pressed between the first rib 220 and the base rib 230. This can also be understood as forming an interference fit between the first tightening strap 300 and the first groove 222. Therefore, when the bundle is transported through the countersunk hole 2111, the first tightening strap 300 cannot slide relative to the limiter 200 in the height direction of the battery module 100, thereby preventing the first tightening strap 300 from rubbing against the limiter 200 to generate metal debris. This also prevents the metal debris from accumulating in the box of the battery pack 10 and causing electrical conduction with the battery module 100 to create a safety risk.

[0050] Referring to Figures 1, 2, and 3, in some embodiments, the battery pack 10 further includes a second tightening strap 400, and the retaining member 200 further includes a second rib 240. The second rib 240 protrudes from the side surface 212 and can extend along the height of the battery module 100, such that the first rib 220, the second rib 240, and the base rib 230 are all aligned. The base rib 230 is located between the first rib 220 and the second rib 240. The second rib 240 and the base rib 230 are spaced apart along the height of the battery module 100. The space between the second rib 240 and the base rib 230 forms a second groove 242. Specifically, the second rib 240, the base rib 230, and the side surface 212 collectively define the second groove 242. The second groove 242 also extends along the length of the battery module 100, such that the first groove 222 and the second groove 242 are parallel to each other. The second tightening band 400 serves the same function as the first tightening band 300. It also surrounds the battery module 100 and fits over the main body 210, sandwiching the battery module 100 between the two retaining members 200. This strengthens the binding. The second tightening band 400 cooperates with the second groove 242, preventing the second tightening band 400 from disengaging from the second groove 242 when the battery module 100 length changes, causing the two retaining members 200 to approach each other.

[0051] In some embodiments, the second tightening strap 400 can be made of a plastic material, for example, to impart a certain degree of elasticity to the second tightening strap 400. The protrusion height of the second rib 240 relative to the side surface 212 is constant, and the protrusion of the second rib 240 relative to the side surface 212 is equal to that of the base rib 230. Because the material of the second tightening strap 400 is softer than that of the first tightening strap 300, the second rib 240 does not need to be provided with a guide slope 221, as is the case with the first rib 220. This significantly reduces the processing cost of the stopper 200, thereby reducing the manufacturing cost of the battery pack 10.

[0052] In some embodiments, the width of the second tightening band 400 can be greater than or equal to the width of both the second groove 242, so that the second tightening band 400 is pressed tightly between the second rib 240 and the base rib 230. This can be understood as forming an interference fit between the second tightening band 400 and the second groove 242. Therefore, when the bundle is moved through the countersunk hole 2111, the second tightening band 400 cannot slide relative to the retaining member 200 in the height direction of the battery module 100, thereby preventing the second tightening band 400 from rubbing against the retaining member 200 and generating metal debris. This also prevents the metal debris from accumulating inside the battery pack 10 and creating electrical conduction with the battery module 100, which could pose a safety risk.

[0053] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0054] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery pack, characterized in that: include: A battery module, comprising a plurality of battery cells, wherein the battery cells are arranged along a thickness direction of the battery cells; a stopper abutting against an end of the battery module in the thickness direction of the battery cell, the stopper being provided with a first groove extending in the thickness direction of the battery cell; and A first tightening band is arranged around the battery module and sleeved on the limiting member along the height direction of the battery core, and the first tightening band cooperates with the first groove.

2. The battery pack according to claim 1, characterized in that: The limiting member includes a main body, a basic convex rib and a first convex rib, the first tightening belt is sleeved on the main body, the main body has a side surface extending along the thickness direction of the battery cell, the basic convex rib and the first convex rib are spaced and protruded on the side surface along the height direction of the battery module, the first convex rib is closer to the upper cover of the battery cell in the battery module than the basic convex rib, and the first groove is formed between the basic convex rib and the first convex rib.

3. The battery pack according to claim 2, characterized in that: An end of the first convex rib away from the base convex rib extends to an end of the side surface close to the upper cover.

4. The battery pack according to claim 2, characterized in that: The first convex rib has a guiding inclined surface, and the distance from the guiding inclined surface to the side surface gradually increases along the installation direction of the first tightening band.

5. The battery pack according to claim 4, characterized in that: The angle between the guiding inclined surface and the side surface ranges from 2° to 10°.

6. The battery pack according to claim 4, characterized in that: The maximum distance from the guide slope to the side surface is 0.5 mm to 1 mm.

7. The battery pack according to claim 4, characterized in that: There is a first distance between two sections of the first tightening band extending in the thickness direction of the battery core, and there is a second distance between two guide inclined surfaces arranged opposite to each other on the same limiting member, and the first distance is smaller than the second distance.

8. The battery pack according to claim 2, characterized in that: The basic convex rib has a convex surface, and the distance from the convex surface to the side surface remains constant, and the value range of the distance from the convex surface to the side surface is 1 mm to 3 mm.

9. The battery pack according to claim 8, characterized in that: The distance from the protruding surface to the side surface is greater than the thickness of the first tightening band, and the difference between the distance from the protruding surface to the side surface and the thickness of the first tightening band is greater than half of the thickness of the first tightening band.

10. The battery pack according to claim 2, characterized in that: The first tightening strap includes a strap body and an insulating sleeve, the strap body is made of steel material and includes a first section and a second section connected to each other, the first section is sleeved on the main body, the second section is located outside the main body and corresponds to the battery module, and the insulating sleeve is made of flexible material and sleeved on the second section.

11. The battery pack according to claim 10, characterized in that: The first section also includes an embedding portion matched with the first groove, and the insulating sleeve is sleeved on at least a portion of the embedding portion.

12. The battery pack according to claim 2, characterized in that: The width of the first tightening band is greater than or equal to the width of the first groove.

13. The battery pack according to claim 2, characterized in that: The main body also has an end surface extending in a direction perpendicular to the thickness of the battery core, the first tightening band is sleeved on the end surface, and a countersunk hole is opened on the end surface.

14. The battery pack according to claim 2, characterized in that: The main body has an end surface extending in a direction perpendicular to the thickness of the battery cell, the end surface and the side surface are equal in size in the height direction of the battery module, and the area of ​​the end surface is larger than the area of ​​the side surface.

15. An electricity system, characterized in that: A battery pack comprising any one of claims 1 to 14.

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