Battery, battery module and battery pack

Abstract

Battery, characterized in that the battery comprises: a housing having a large housing surface; a battery cell arranged in the housing, wherein the battery cell comprises a separator and several electrode plates, the several electrode plates being arranged in a stacked direction, and wherein the stacking direction of the several electrode plates is facing the large housing surface; and wherein the battery cell has a first and a second end which are arranged opposite each other in the stacking direction of the electrode plates;wherein the electrode plates comprise several first electrode foils and several second electrode foils, wherein the several first electrode foils and the several second electrode foils are arranged alternately stacked on top of each other to form a discontinuous stacking structure, and wherein the first electrode foils form the outermost layer of the stacking structure at the first end and the outermost layer of the stacking structure at the second end; wherein the separator is arranged between two adjacent electrode plates, and wherein the separator extends at least to one side of the electrode plate facing the large housing surface at the outermost layer in order to separate the electrode plate from the housing;and wherein the separator comprises an inner layer section and an outer layer section connected to each other, the inner layer section being arranged between adjacent first and second electrode foils, the inner layer section covering a side of the first electrode foil at the second end facing the first end, and the tail end of the inner layer section being arranged between the first electrode foil at the second end and the adjacent second electrode foil, and wherein the inner layer section also comprising the head end, the head end at least partially covering the side surface of the first electrode foil located at the first end;wherein the outer layer section comprises a start end and a tail end, the start end being connected to the tail end of the inner layer section, and wherein the outer layer section extends in the direction of the first end along the stacking direction of the electrode plate and winds up the outside of the first electrode foil, the second electrode foil and the inner layer section, and covers one side of the first electrode foil facing the large housing surface at the second end, and wherein, in the stacking direction of the electrode plate, the length of the head end of the inner layer section is l, and wherein 0.1 mm ≤ 1 ≤ 5 mm.

Description

This application is a divisional application of the patent application with the application number “2025106688494”, the filing date “May 23, 2025” and the invention title “Battery and battery module, battery pack”. TECHNICAL AREA The present invention relates to battery technology, in particular a battery, a battery module and a battery pack. STATE OF THE ART A stacked battery is a type of lithium-ion battery consisting of a cathode foil, a separator, and an anode foil stacked sequentially to form a multi-layered battery cell. Compared to conventional coiled batteries, stacked batteries offer better space utilization and more uniform current distribution, making them suitable for high-energy-density, high-power applications such as electric vehicles and energy storage systems. The separator plays a crucial role in the stacked battery. During the assembly process, the separator is typically placed between the cathode and the anode to prevent them from coming into direct contact and causing a short circuit.However, during the manufacturing process of the stacked battery, foreign matter such as metal particles and dust can be introduced and become lodged in the battery casing. When the battery cell is installed in the casing, these foreign matter can puncture the separator, leading to direct contact between the cathode and the anode and consequently to an internal short circuit or even thermal runaway. CONTENT OF THE PRESENT INVENTION The object of the present invention is to provide a battery, a battery module and a battery pack in which the length of the head end of the inner layer section of the separator is adjusted to avoid an excessive increase in the thickness of the side surface of the battery cell. To achieve the above-mentioned objectives, the present invention employs the following technical solutions: a battery comprising: a housing having a large housing surface; a battery cell arranged in the housing, wherein the battery cell comprises a separator and several electrode plates, the several electrode plates being arranged in a stacked manner, and wherein the stacking direction of the several electrode plates is facing the large housing surface; and wherein the battery cell has a first and a second end arranged opposite each other in the stacking direction of the electrode plates;wherein the electrode plates comprise several first electrode foils and several second electrode foils, wherein the several first electrode foils and the several second electrode foils are arranged alternately stacked on top of each other to form a discontinuous stacking structure, and wherein the first electrode foils form the outermost layer of the stacking structure at the first end and the outermost layer of the stacking structure at the second end; wherein the separator is arranged between two adjacent electrode plates, and wherein the separator extends at least to one side of the electrode plate facing the large housing surface at the outermost layer in order to separate the electrode plate from the housing;and wherein the separator comprises an inner layer section and an outer layer section connected to each other, the inner layer section being arranged between adjacent first and second electrode foils, the inner layer section covering a side of the first electrode foil at the second end facing the first end, and the tail end of the inner layer section being arranged between the first electrode foil at the second end and the adjacent second electrode foil, and wherein the inner layer section also comprising the head end, the head end at least partially covering the side surface of the first electrode foil located at the first end;wherein the outer layer section comprises a start end and a tail end, the start end being connected to the tail end of the inner layer section, and wherein the outer layer section extends in the direction of the first end along the stacking direction of the electrode plate and winds up the outside of the first electrode foil, the second electrode foil and the inner layer section, and covers one side of the first electrode foil facing the large housing surface at the second end, and wherein, in the stacking direction of the electrode plate, the length of the head end of the inner layer section is l, and wherein 0.1 mm ≤ 1 ≤ 5 mm. Based on the aforementioned battery, the present application also provides a battery module comprising at least two of the aforementioned batteries, wherein the two batteries are electrically connected to each other by being connected in series or in parallel. Based on the aforementioned battery module, the present application also provides a battery pack comprising an outer shell and at least two of the aforementioned battery modules, wherein two battery modules are arranged in the outer shell and wherein the two battery modules are electrically connected to each other. Compared to existing technology, a battery, battery module, and battery pack designed according to the present invention have the following advantages: this battery improves the covering effect of the separator on the first electrode foil by having the head end of the inner layer section of the separator cover the side surface of the first electrode foil at the first end, thereby reducing the risk of the first electrode foil overlapping with the housing; and by controlling the length of the head end of the inner layer section, the length of the head end of the inner layer section is kept within a suitable range to avoid an excessive increase in the thickness of the side surface of the battery cell, thereby reducing the risk of the first electrode foil overlapping with the housing.The battery module and battery pack use the aforementioned battery and exhibit the beneficial effects of the aforementioned battery. BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is a schematic representation of the battery in an embodiment of the present invention; Fig. 2 is a front view of the battery in an embodiment of the present invention; Fig. 3 is a sectional view along AA in Fig. 2; Fig. 4 is an enlarged view of B in Fig. 3; Fig. 5 is an enlarged view of C in Fig. 3; Fig. 6 is a schematic diagram of the interaction between the insulating film and the battery cell in an embodiment of the present invention; Fig. 7 is a schematic representation of the battery housing with two battery cells in an embodiment of the present invention; and Fig. 8 is a schematic diagram of the interaction between the battery cell and the tab in an embodiment of the present invention. In the drawings: 100. Battery; 1. Casing; 1a. Large casing area; 2. Battery cell; 2a. Separator; 2a1. Outer layer section; 2a2. Inner layer section; 2a3. Outer layer section; 2b. Electrode plate; 2b1. Cathode foil; 2b2. Anode foil; 2c. Large battery cell area; 2d. First end; 2e. Second end; 3. Insulating film; 4. Tab; 5. Cover plate. DETAILED DESCRIPTION Specific implementations of the present invention are described in more detail below with reference to the accompanying drawings and exemplary embodiments. The following exemplary embodiments serve to illustrate the invention but are not intended to limit its scope. In describing the present invention, it should be understood that when an element is described as "attached" or "arranged" on another element, it may be placed either directly on that other element or indirectly on that other element. When an element is described as "connected" to another element, it may be directly connected to the other element or indirectly connected to the other element. The terms "mounting," "connecting," and "connecting" are to be understood in the broadest sense; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical or electrical connection; they may refer to a direct connection or an indirect connection via an intermediate medium; and they may refer to internal communication between two elements or to interaction between the two elements.The average person skilled in this field can understand the specific meanings of the foregoing terms in the present invention according to specific situations. In describing the present invention, it should be understood that the orientations or positional relationships indicated by the terms "height", "top", "bottom", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like, which are used in the present invention, are the orientations or positional relationships shown based on the drawings and serve only for the convenience and simplification of the description of the present invention, rather than indicating or implying that the device or element in question must have a particular orientation or orientation or be designed and operated in a particular orientation, and should therefore not be construed as limiting the present invention. In describing the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be interpreted as indicating or implying a relative meaning or implicitly specifying the set of technical features mentioned. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of these features. Examples of implementation With reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8, the present embodiment provides a battery 100 comprising a housing 1, a cover plate 5 and a battery cell 2, wherein the housing 1 has a large housing surface 1a, and the cover plate 5 is connected to the housing 1, thereby isolating the interior of the housing 1 from the external environment.The battery cell 2 is arranged in the housing 1, and the battery cell 2 comprises a separator 2a and several electrode plates 2b, wherein the electrode plates 2b are arranged stacked on top of each other to form a discontinuous stacking structure, and wherein the stacking direction of the several electrode plates 2b faces the large housing area 1a, and the separator 2a is arranged between two adjacent electrode plates 2b, and the separator 2a extends at least to one side of the electrode plate 2b facing the large housing area 1a at the outermost layer to form the outer layer portion 2a1. The outer layer portion 2a1 covers one side of the electrode plate 2b facing the large housing area 1a at the outermost layer to separate the electrode plate 2b from the housing 1 and to form the large battery cell area 2c. It should be noted that the battery 100 of the present embodiment is a stacked battery 100. A stacked battery is a battery structure built up by stacking several electrode plates, wherein the cathode, the anode, and the separator are stacked alternately to form a multilayer structure. The cathode foil is typically a metal foil (usually aluminum foil) coated with an active cathode material (such as ternary lithium, lithium iron phosphate, or the like). The anode foil is typically a metal foil (usually copper foil) coated with an active anode material (such as graphite, silicon-based material, or the like). The separator is an insulating film located between the cathode and the anode, serving to prevent short circuits while allowing the passage of lithium ions. It should be noted that the housing 1 serves to encapsulate components such as the battery cell 2 and the electrolyte. The housing 1 can have various shapes and sizes, e.g., cuboids, hexagonal prisms, or the like; the shape of the housing 1 can be determined according to the specific shape and size of the battery cell 2. The housing 1 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloys, plastic, and the like. It should be noted that the large housing area 1a is the surface with the largest area in the housing 1 of the battery 100. The large housing area 1a is typically the main load-bearing component of the housing 1 and influences the overall structural strength of the housing 1; it is also typically the main area for heat dissipation from the housing 1 and thus influences the heat dissipation efficiency of the battery 100. It should be noted that the large battery cell area 2c refers to the larger side surface of battery cell 2, which is usually a part with the largest area of ​​battery cell 2 when the electrode plate 2b and the separator 2a are stacked, and the large battery cell area 2c is usually oriented perpendicular to the stacking direction of the electrode plate 2b. It is understandable that the electrode plate 2b of the battery 100 typically has two types of electrode foils with opposite polarities, namely a cathode foil 2b1, which serves as the second electrode foil, and an anode foil 2b2, which serves as the first electrode foil. The electrode arrangement of the battery 100 functions by the movement of metal ions between the cathode foil 2b1 and the anode foil 2b2. The cycling process of the battery cell is the process by which metal ions move from the cathode foil 2b1 to the anode foil 2b2 and then from the anode foil 2b2 to the cathode foil 2b1. Referring to Fig.In the battery cell 2 of the present embodiment, the cathode foil 2b1 and the anode foil 2b2 are stacked alternately one after the other, i.e., the cathode foil 2b1 and the anode foil 2b2 are stacked one after the other in the sequence anode foil 2b2 - cathode foil 2b1 - anode foil 2b2 - cathode foil 2b1 - anode foil 2b2, thereby forming a discontinuous stacking structure, and the anode foil 2b2 is located in the outermost layer of the stacking structure, i.e., on one of the large housing surfaces 1a.It should be noted that the battery cell 2 of the present embodiment is a stacked battery cell in which several electrode plates 4b are stacked on top of each other to form the discontinuous stacking structure, which means that any two adjacent cathode foils 2b1 have a discontinuous structure and / or any two adjacent anode foils 2b2 have a discontinuous structure. During the manufacturing process of battery 100, the electrode plate 2b, due to its discontinuous structure, must be cut to obtain a single electrode foil before it can be stacked to form battery cell 2. The cut area of ​​electrode plate 2b is the weak point of the electrode foil. During use of battery 100, the corners and cut edges of electrode plate 2b are susceptible to material abrasion due to pressure, which can puncture the separator 2a, leading to a short circuit between battery cell 2 and the housing 1. Simultaneously, during use of battery 100, the large surface area 2c of the battery cell tends to expand, further increasing the risk of a short circuit between battery cell 2 and the housing 1.Therefore, the battery 100 of the present embodiment adjusts the distance between the electrode foil 2b and the housing 1 such that the minimum vertical distance between a side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and a side of the large housing surface 1a facing the battery cell 2 is h, where 0.05mm ≤ h ≤ 5mm. For example, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm and 5 mm. A suitable distance between the battery cell 2 and the housing 1 is maintained by adjusting the distance between the electrode plate 2b of the battery cell 2 and the housing 1. This prevents the separator 2a of the battery cell 2 from adhering to the inside of the housing 1 when the battery cell 2 is inserted into the housing 1. This prevents foreign bodies such as metal particles and dust or the like, which adhere to the housing 1, from penetrating the separator 2a, which would cause the battery cell 2 to overlap with the housing 1 and thus cause a short circuit in the battery 100. By maintaining a suitable distance between the battery cell 2 and the housing 1, the battery cell 2 can optimally utilize the interior space of the housing 1, thus ensuring the efficient use of the interior space of the housing 1. To verify that, when the minimum vertical distance h of the battery 100 provided by the present embodiment meets the aforementioned range, the battery 100 is able to provide good insulation performance compared to other batteries 100 of the present embodiment, ten test series were carried out in this embodiment, as shown in Table 1 below: In Table 1, test examples 1 to 10 are based on the structure of the battery 100 of the present embodiment for testing, i.e., the minimum vertical distance h of the battery 100 of test examples 1 to 10 meets the aforementioned range. Comparison examples 1 and 2 are different battery structures whose minimum vertical distance h does not meet the aforementioned range. Insulation performance test procedure: As shown in Table 1, the battery cell and the casing are mounted at different heights h, and the cover plate is welded and attached to the casing using laser welding technology. After completion of processes such as liquid injection and formation, battery samples of uniform size are obtained; the battery's cathode material is lithium iron phosphate. First, the battery is charged to 3.25 V at a current of 1 / 3C. After a 10-minute rest period, it is then discharged to 2.5 V at a current of 1 / 3C and subsequently left to rest for 1 hour. At this point, the battery's open-circuit voltage is measured and recorded and designated V1. The above charge and discharge process is then repeated. After a 10-minute rest period, 500 cycles are performed.After completing the cycles, a rest period of 50 minutes is observed. The battery's open-circuit voltage is then measured and recorded again and designated V2. The voltage difference of the battery after the cycles is calculated using the formula ΔV = V1 - V2. The larger the voltage difference, the worse the insulation performance of the battery cells; conversely, the smaller the voltage difference, the better the insulation performance of the battery cells. Discharge capacity test procedure: according to the mounting requirements for different heights h in Table 1, the battery cell is mounted to the housing, and the cover plate is welded to the housing using laser welding technology. After completion of the liquid injection and forming steps, battery samples of the same size are obtained; the battery's cathode material is also lithium iron phosphate. The battery is initially charged to 3.25 V with a current of 1 / 3C.After a 10-minute rest period, the battery is discharged to 2.5 V at a current of 1 / 3C and then left to rest for 10 minutes. It is then recharged to 3.25 V at a current of 1 / 3C. After another 10-minute rest period, it is discharged to 2.5 V at a constant current of 10 A. The discharge time is recorded and denoted as T hours. The battery's discharge capacity can be calculated using the formula C = 10 × T. If the calculated capacity is less than 100 Ah, the battery sample is considered unsuitable. Table 1. Test example 10,050,18124,2 Test example 20,10,13121,6 Test example 30,20,11119,5 Test example 41.00.08117.7 Test example 51,50,06116,9 Test example 62.50.05114.2 Test example 730.03111.7 Test example 83.50.03107.2 Test example 94.50.02103.6 Test example 1050.01101.5 Comparative example 10,030,24125,6 Comparative example 25,20,0198,3 As shown in Table 1, the voltage difference of battery 100 is small and the insulation performance is good when the minimum vertical distance h between a side of electrode plate 2b facing the large casing area 1a at the outermost layer and a side of the large casing area 1a facing battery cell 2 remains within the range mentioned above, and the discharge capacity of battery 100 is good. However, if the minimum vertical distance h between a side of electrode plate 2b facing the large casing area 1a at the outermost layer and a side of the large casing area 1a facing battery cell 2 is less than 0.05 mm, the increase in discharge capacity is not significant. However, with continued charge and discharge cycles, this small gap can lead to a decrease in insulation performance.However, if the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 is greater than 5 mm, the discharge capacity of the battery will be lower. It is understood that the separator 2a itself also possesses a certain protective effect. The thicker the separator 2a, the more difficult it is for foreign bodies adhering to the housing 1 to penetrate the separator 2a. The thickness of the separator 2a naturally affects the electrode plates 2b and their fit when stacked. If the thickness of the separator 2a is too great, this easily leads to an excessive thickness of the battery cell 2, which impairs the assembly of the battery cell 2 with the housing 1 and increases the internal resistance of the battery 100. Therefore, the thickness of the separator 2a should be within a suitable range. For example, as an example for this embodiment, the separator 2a has a thickness of T1, where 6 µm ≤ T1 ≤ 400 µm.Since the separator 2a has a sufficiently good penetration resistance, the battery cell 2 can be brought closer to the housing 1 in order to further improve the utilization of the interior of the housing 1. Therefore, the minimum vertical distance between a side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and a side of the large housing surface 1a facing the battery cell 2 is h, if the thickness T1 of the outer layer part 2a1 satisfies the condition 6 µm ≤ T1 ≤ 400 µm, and where 0.05 mm ≤ h ≤ 1 mm applies. For example, the thickness T1 of the separator 2a can be one of the following sizes: 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 20 µm, 30 µm, 40 µm, 50 µm, 60 µm, 70 µm, 80 µm, 90 µm, 100 µm, 150 µm, 200 µm, 250 µm, 300 µm, 350 µm and 400 µm, and the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, The dimensions are 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm. It should be noted that the separator 2a can be a single-material separator 2a made of PP or PE material, or a composite separator 2a, such as a ceramic-coated separator 2a. Different materials influence the puncture resistance of the separator 2a; therefore, the puncture resistance of the separator 2a can also be described by its puncture strength (PPS). For example, the puncture strength of the outer layer part 2a1, as an example for this embodiment, is PPS, where 200 kgf ≤ PPS ≤ 600 kgf. If the puncture strength of the separator 2a meets the specified conditions, its puncture resistance is sufficient to move the battery cell 2 closer to the housing 1, thus further improving the utilization of the interior space of the housing 1.Therefore, if the puncture resistance PPS of the outer layer part 2a1 satisfies the condition 200 kgf ≤ PPS ≤ 600 kgf, the minimum vertical distance between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 is h, where 0.05mm ≤ h ≤ 1.5mm. For example, the puncture resistance PPS of the outer layer part 2a1 can be one of the following values: 200 kgf, 250 kgf, 300 kgf, 350 kgf, 400 kgf, 450 kgf, 500 kgf, 550 kgf, and 600 kgf, and the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm. 1.3 mm, 1.4 mm and 1.5 mm. In some batteries 100, an insulating film 3 is arranged between the battery cell 2 and the housing 1 to ensure the safety, reliability, and performance stability of the battery 100. Referring to Fig. 6, as an example of this embodiment, the battery 100 also includes an insulating film 3 extending between the outer layer part 2a1 and the housing 1 to separate the separator 2a from the housing 1. In this way, the insulating film 3 is placed between the battery cell 2 and the housing 1, thereby isolating the battery cell 2 from the housing 1 and preventing contact between the tab 4 or the electrode plate 2b of the battery cell 2 and the housing 1. The insulating film 3 is typically made of a high-resistance material; its high resistance blocks the leakage current circuit between the battery cell 2 and the housing 1, thus ensuring the proper operation of the battery 100. Furthermore, the insulating film 3 can provide a certain mechanical protective effect between the insulating film 2a and the housing 1, thereby reducing the risk of foreign bodies adhering to the inside of the housing 1 puncturing the separator 2a. Therefore, the battery cell 2 with the attached insulating film 3 can be moved closer to the housing 1. The minimum vertical distance between a side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and a side of the large housing surface 1a facing the battery cell 2 is h, where 0.05 mm ≤ h ≤ 1 mm. For example, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm. The insulating film 3 can be joined to the separator 2a by gluing, mechanical fastening, hot pressing, lamination, or similar methods. The fitting structure of the two typically depends on the type of battery 100, the process requirements, and the process specifications. For example, as an example of this embodiment, the insulating film 3 is glued to the outer layer part 2a1. Specifically, the insulating film 3 can be glued to the separator 2a with adhesive or hot melt adhesive, so that the insulating film 3 and the separator 2a are firmly joined and any relative displacement between the insulating film 3 and the separator 2a is prevented.Of course, the self-adhesive insulating film 3 can also adhere to foreign objects inside the housing 1; therefore, the separator 2a should be positioned at a suitable distance from the housing 1 to increase the space between the separator 2a and the housing 1 and thus reduce the risk of foreign objects becoming trapped. Therefore, the minimum vertical distance between a side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and a side of the large housing surface 1a facing the battery cell 2 is h, where 0.1 mm ≤ h ≤ 1 mm. For example, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm. It is understood that during the assembly of the battery cell 2, the cathode foil 2b1, the separator 2a, and the anode foil 2b2 are stacked successively on top of each other. The upper and lower surfaces of the electrode plate 2b differ due to the stacking direction of the electrode plate 2b. The separator 2a is positioned between the cathode foil 2b1 and the anode foil 2b2 and covers both the upper and lower surfaces of the cathode foil 2b1 and the anode foil 2b2. This separates the adjacent cathode foil 2b1 and the adjacent anode foil 2b2 from each other, preventing them from coming into direct contact. The separator 2a is typically a continuous film extending from the inside of the stacked structure to the outside of the stacked structure and covering the outside of the stacked structure.thereby separating the electrode plate 2b from the housing 1. Referring to Fig. 3, Fig. 4 to Fig. 5, which serve as an example of the separator 2a covering the electrode plate 2b, the battery cell 2 has a first end 2d and a second end 2e, which are arranged opposite each other in the stacking direction of the electrode plate 2b; the electrode plate 2b comprises several first electrode foils and several second electrode foils, namely several anode foils 2b2 and several cathode foils 2b1, the several anode foils 2b2 and the several cathode foils 2b1 are stacked alternately on top of each other, thus forming a discontinuous stacking structure, and the anode foil 2b2 forms the outermost layer of the stacking structure at the first end 2d; The separator 2a comprises an inner layer section 2a2 and an outer layer section 2a3, which are connected to each other; the inner layer section 2a2 is arranged between the cathode foil 2b1 and the anode foil 2b2.which are adjacent to each other, and the tail end of the inner layer section 2a2 is between the anode foil 2b2 at the second end 2e and the adjacent cathode foil 2b1; The outer layer section 2a3 comprises a start end and a tail end, the start end of the outer layer section 2a3 is connected to the tail end of the inner layer section 2a2, and the outer layer section 2a3 extends towards the first end 2d along the stacking direction of the electrode plate 2b and is wrapped around the outside of the cathode foil 2b1, the anode foil 2b2 and the inner layer section 2a2 and covers one side of the anode foil 2 facing the large housing surface 1a at the second end 2e to form the outer layer part 2a1, and the tail end of the outer layer section 2a3 extends towards the first end 2d and overlaps at least partially with the start end of the outer layer section 2a3. It should be noted that in this example of covering, the overlap area between the tail end of the outer layer section 2a3 and the head end of the outer layer section 2a3 affects the fit between the separator 2a and the electrode plate 2b. In the stacking direction of the electrode plate 2b, the overlap distance between the tail end and the head end of the outer layer section 2a3 is m. If the overlap distance m between the tail end and the head end of the outer layer section 2a3 is too small, this can easily lead to the tail end and the head end of the outer layer section 2a3 separating from each other, thereby exposing the anode foil 2b2 of the outer layer, which in turn can lead to the anode foil 2b2 overlapping with the housing 1.If the overlap distance m between the tail end and the head end of the outer layer section 2a3 is too large, this can easily lead to the separator 2a becoming too thick at the side of the battery cell 2, which impairs the assembly and fit between the battery cell 2 and the housing 1. Therefore, the overlap distance m between the tail end and the head end of the outer layer section 2a3 should be kept within a certain range. For example, as an example of this embodiment, the overlap distance m between the tail end and the head end of the outer layer section 2a3 satisfies the condition 0.2 mm ≤ m ≤ 10 mm. In this way, the separator 2a achieves better coverage of the outermost anode foil 2b2, and it is unlikely that the anode foil 2b2 will overlap with the housing 1. Of course, in this case the battery cell 2 can also be moved closer to the housing 1 to further improve the utilization of the interior space of the housing 1; therefore, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can satisfy the condition 0.05 mm ≤ h ≤ 1.5 mm.For example, the overlap distance m between the tail end and the head end of the outer layer section 2a3 can be one of the following sizes: 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm and 10 mm; the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, 0.06 mm, The dimensions are 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm and 1.5 mm. In the stacked battery cell 2, the battery cell 2 has a first end 2d and a second end 2e, which are arranged opposite each other along the stacking direction of the electrode plate 2b. It should be noted that the separator 2a typically covers the outside of the anode foil 2b2 at the first end 2d and the outside of the anode foil 2b2 at the second end 2e, i.e., the side of the anode foil 2b2 facing the second end 2e, to ensure that the anode foil 2b2 is separated from the housing 1. Therefore, in this example of covering shown in Fig. 3, Fig. 4 to Fig. 5, the inner layer section 2a2 covers the outside of the anode foil 2b2 located at the first end 2d, and the tail end of the inner layer section 2a2 is positioned between the anode foil 2b2 at the second end 2e and the adjacent cathode foil 2b1.In order to allow the separator 2a to cover the side of the anode foil 2b2 at the first end 2d, the head end of the inner layer section 2a2 normally starts at the side of the anode foil 2b2 at the first end 2d and partially covers the side surface of the anode foil 2b2 at the first end 2d. The inner layer section 2a2 typically has a head end, and the head end of the inner layer section 2a2 covers the side surface of the anode foil 2b2 located at the first end 2d. This can improve the covering effect of the separator 2a on the anode foil 2b2, thereby reducing the risk of the anode foil 2b2 overlapping with the housing 1. Naturally, the length of the head end of the inner layer section 2a2 should not be too great in order to avoid excessively increasing the thickness of the side surface of the battery cell 2. Referring to Fig. 5, as an example of this embodiment, the length of the head end of the inner layer section 2a2 in the stacking direction of the electrode plate 2b is l, where 0.1 mm ≤ 1 ≤ 5 mm.Since the risk of the anode foil 2b2 overlapping with the housing 1 is reduced, the battery cell 2 can of course also be moved closer to the housing 1 in order to further improve the utilization of the interior of the housing 1, therefore the minimum vertical distance h between a side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and a side of the large housing surface 1a facing the battery cell 2 can satisfy the condition 0.05 mm ≤ h ≤ 2 mm.For example, the length l of the head end of the inner layer section 2a2 can be one of the following sizes: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm; the minimum vertical distance h between a side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and a side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm and 2 mm. Depending on the application scenario of the battery 100, the structures of some batteries 100 are equipped with multiple battery cells 2 to meet different voltage, capacity, and power requirements. Referring to Fig. 7, as an example of this embodiment, the battery 100 comprises two battery cells 2, wherein the battery cells 2 are arranged side by side in the housing 1, and wherein the arrangement direction of the two battery cells 2 is the same as the stacking direction of the electrode plate 2b. It should be noted that battery cell 2 expands during operation. For example, during the charging and discharging process of battery 100, lithium ions are inserted into and extracted from the cathode and anode materials, which can lead to volume changes in the electrode materials. Alternatively, during the charging and discharging process of battery 100, the internal stress generated by the volume change of the electrode material can also cause battery cell 2 to expand as a whole. If two or more battery cells 2 are arranged in the housing 1, the expansion of one battery cell 2 leads to a displacement of the position of other battery cells 2, causing the battery cells 2 near the housing 1 to come into contact with the housing 1 and creating a risk of overlap between the battery cells 2 and the housing 1.Therefore, the minimum vertical distance h between a side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and a side of the large housing surface 1a facing the battery cell 2 must satisfy the condition 0.15 mm ≤ h ≤ 5 mm. For example, the minimum vertical distance h between a side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and a side of the large housing surface 1a facing the battery cell 2 can be one of the following values: 0.15 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm. When two or more battery cells 2 are arranged in the housing 1, the way in which the separator 2a covers the battery cells 2 also affects the assembly and fit between the battery cells 2 and the housing 1. Referring to Fig.Figure 7 describes as an example that two battery cells 2 are arranged in the housing 1, the battery cells 2 each have a first end 2d and a second end 2e which are arranged opposite each other along the stacking direction of the electrode plates 2b, and the second ends 2e of two adjacent battery cells 2 are arranged opposite each other; furthermore, the electrode plates 2b in the battery cell 2 shown in Figure 7 consist of a cathode foil 2b1 and an anode foil 2b2, the cathode foil 2b1 and the anode foil 2b2 are stacked alternately on top of each other and thus form a stacking structure, and the anode foil 2b2 is located in the outermost layer of the stacking structure. In the present embodiment, the separator 2a shown in Fig. 7 has the same covering method as the separator 2a shown in Fig. 3. Specifically, the separator 2a comprises an inner layer section 2a2 and an outer layer section 2a3, which are connected to each other. The inner layer section 2a2 covers the outer surface of the anode foil 2b2 located at the first end 2d, and the tail end of the inner layer section 2a2 is arranged between the anode foil 2b2 at the second end 2e and the adjacent cathode foil 2b1. The head end of the inner layer section 2a2 partially covers the side surface of the anode foil 2b2 located at the first end 2d. Understandably, depending on the connection method between the separator 2a and the anode foil 2b2, the area covered by the head end of the inner layer section 2a2 also varies.In the structure of some batteries 100, the inner layer section 2a2 can also cover the entire side surface of the anode foil 2b2 located at the first end 2d. The outer layer section 2a3 of the separator 2a is connected to the tail end of the inner layer section 2a2, and the outer layer section 2a3 is wrapped around the outside of the inner layer section 2a2 along the stacking direction of the electrode plate 2b, covering the anode foil 2b2 at the second end 2e to form the outer layer section 2a1, and the tail end of the outer layer section 2a3 extends towards the head end of the outer layer section 2a3 and overlaps with this head end of the outer layer section 2a3.In this way, the inner layer section 2a2 of the separator 2a in each battery cell 2 can form a first layer of the film structure at the first end 2d, and the outer layer section 2a3 of the separator 2a wraps around the outside of the inner layer section 2a2 to form a second layer of the film structure at the first end 2d. This results in both battery cells 2 having a two-layer film structure at the first end 2d, so that the distance between the side surface of the battery cell 2 at the first end 2d and the electrode plate 2b at the first end 2d is greater than the distance between the side surface of the battery cell 2 at the second end 2e and the electrode plate 2b at the second end 2e in the stacking direction of the electrode plate 2b. This reduces the risk of foreign bodies adhering to the housing 1 puncturing the separator 2a.With the decreasing risk of foreign bodies penetrating the separator 2a, the battery cell 2 can of course be moved closer to the housing 1 to further improve the utilization of the interior of the housing 1; therefore, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a on the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can satisfy the condition 0.15mm ≤ h ≤ 2mm. For example, the minimum vertical distance h between one side of the electrode plate 2b facing the large housing surface 1a at the outermost layer and one side of the large housing surface 1a facing the battery cell 2 can be one of the following sizes: 0.15 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm and 2 mm. The thickness of battery cell 2 naturally also influences the risk of foreign objects penetrating separator 2a. The thicker the battery cell, the greater the expansion and the larger the expansion path. Therefore, by adjusting the distance between electrode plate 2b and housing 1 to the thickness of battery cell 2, adhesion of separator 2a to the inside of housing 1 can be further prevented. This prevents foreign objects adhering to the housing 1 from penetrating separator 2a, which would cause battery cell 2 to overlap with housing 1 and thus create a short circuit in battery 100. As an example for the present embodiment, it is provided that the thickness of battery cell 2 in the stacking direction of electrode plate 2b is Tbatterycell, where 8 mm ≤ Tbatterycell ≤ 30 mm.For example, the thickness T of battery cell 2 can be one of the following values: 8 mm, 9 mm, 10 mm, 11 mm, 13 mm, 15 mm, 18 mm, 20 mm, 21 mm, 23 mm, 25 mm, 28 mm or 30 mm. It is understandable that the electrode arrangement of the battery 100 typically also includes a tab 4, which is electrically connected to the electrode plate 2b. The tab 4 is electrically connected to the electrode plate 2b and serves to conduct the current from the electrode plate 2b via the tab 4 to other components, such as the housing 1 or the terminal. The terminal of the battery 100 is usually located on the housing 1, with one end of the terminal being electrically connected to the tab 4 and the other end exposed on the surface of the housing 1. The tab 4 typically comprises a cathode tab and an anode tab. The cathode tab is electrically connected to the cathode foil 2b1, and the anode tab is electrically connected to the anode foil 2b2. The battery cell 2 is charged and discharged via the cathode and anode tabs. The electrode foil typically comprises a current collector and an active substance layer, with the active substance layer applied to the surface of the current collector. If the electrode foil is a cathode foil 2b1, the current collector material can be aluminum, and the active substance layer material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganese oxide, or the like. If the electrode foil is an anode foil 2b2, the current collector material can be copper, and the active substance layer material can be carbon, silicon, or the like. It is important to note that the width of tab 4 affects the current distribution, mechanical stress, and assembly accuracy of battery 100, as well as the risk of separator 2a being punctured. The width of tab 4 influences the current flow path of the entire electrode foil, thereby affecting the expansion of battery cell 2. If the width of tab 4 is within a suitable range, the expansion of battery cell 2 can be reduced, and tab 4 acts as a buffer to minimize collisions between battery cell 2 and housing 1. If the width of tab 4 is too small, the current flow path of the entire electrode foil is too long, which can easily lead to expansion of battery cell 2. Furthermore, burrs and other foreign matter can easily form at the interface between tab 4 and electrode plate 2b, compromising the insulation between battery cell 2 and housing 1.If the width of tab 4 is too large, the edge of tab 4 tends to warp, which makes assembling battery 100 difficult or causes tab 4 to overlap the housing 1, thus impairing its insulating performance. Furthermore, the width of battery cell 2 affects the voltage distribution inside battery 100 and increases the risk of separator 2a being punctured. For example, if battery cell 2 is too narrow, this can lead to voltage concentration inside battery 100, and the expansion of battery cell 2 exerts greater pressure on separator 2a. Conversely, if battery cell 2 is too wide, this can make aligning electrode plate 2b difficult. Misalignment of electrode plate 2b can lead to local compression or puncture of separator 2a; therefore, the width of battery cell 2 and the width of tab 4 should be kept within a suitable range.As an example of the present embodiment, the battery cell 2 comprises a tab 4 which is electrically connected to the electrode plate 2b, and wherein, with reference to Fig. 8, the width of the battery cell 2, i.e., the length of the battery cell 2 in the lateral direction, is Wbatterycell, and the width of the tab 4, i.e., the length of the tab 4 in the lateral direction, is Wtab, and both satisfy the condition where the lateral direction of the battery cell 2 is the longitudinal direction, as shown in Fig. 8. For example, one of the values ​​0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. Starting from the aforementioned battery 100, the present embodiment also provides a battery module comprising at least two of the aforementioned batteries 100, wherein the two batteries 100 are electrically connected to each other by being connected in series or in parallel. Based on the above-mentioned battery module, the present embodiment also provides a battery pack comprising an outer shell and at least two of the aforementioned battery modules, wherein the two battery modules are arranged inside the outer shell and are electrically connected to each other. In summary, the battery 100 provided by an embodiment of the present invention maintains a suitable distance between the battery cell 2 and the housing 1 by adjusting the distance between the electrode plate 2b of the battery cell 2 and the housing 1. This prevents the separator 2a of the battery cell 2 from adhering to the inside of the housing 1 when the battery cell 2 is inserted into the housing 1. This prevents foreign bodies such as metal particles, dust, or the like, which adhere to the housing 1, from penetrating the separator 2a, which would cause the battery cell 2 to overlap with the housing 1 and thus cause a short circuit in the battery 100. By maintaining a suitable distance between the battery cell 2 and the housing 1, the battery cell 2 can optimally utilize the interior space of the housing 1, thus ensuring the efficient use of the interior space of the housing 1.The battery module of battery 100 and the battery pack of battery 100 use the aforementioned battery 100 and exhibit the advantageous effects of the aforementioned battery 100. The above represents only the preferred embodiments of the present invention. It should be noted that, for the average person skilled in the art, several improvements and substitutions could be made without departing from the technical principles of the present invention. These improvements and substitutions should also be considered within the scope of protection of the present invention. The present invention discloses a battery, a battery module and a battery pack and relates to the field of battery technology. The battery comprises a housing and a battery cell. The housing has a large housing area, and the battery cell is arranged inside the housing. The battery cell comprises a separator and several electrode plates arranged in a stacked position, with the stacking direction of the several electrode plates pointing towards the large housing area. The separator comprises at least one outer layer portion extending to the electrode plate at the outermost layer, the outer layer portion covering one side of the electrode plate facing the large housing area at the outermost layer in order to separate the electrode plate from the housing. Furthermore, in the direction of the stacking direction of the electrode plate, the length l of the first end of the inner layer portion lies within a predetermined area.This battery reduces the risk of the first electrode foil overlapping the casing by ensuring that the first end of the inner layer section covers the side of the first electrode foil at its first end. Furthermore, controlling the length of the first end of the inner layer section prevents an excessive increase in the thickness of the battery cell's side surface, thus reducing the risk of the first electrode foil overlapping the casing. The battery module and battery pack utilize the aforementioned battery and exhibit its beneficial properties.

Claims

Battery, characterized in that the battery comprises: a housing having a large housing surface; a battery cell arranged in the housing, wherein the battery cell comprises a separator and several electrode plates, the several electrode plates being arranged in a stacked direction, and wherein the stacking direction of the several electrode plates is facing the large housing surface; and wherein the battery cell has a first and a second end which are arranged opposite each other in the stacking direction of the electrode plates;wherein the electrode plates comprise several first electrode foils and several second electrode foils, wherein the several first electrode foils and the several second electrode foils are arranged alternately stacked on top of each other to form a discontinuous stacking structure, and wherein the first electrode foils form the outermost layer of the stacking structure at the first end and the outermost layer of the stacking structure at the second end; wherein the separator is arranged between two adjacent electrode plates, and wherein the separator extends at least to one side of the electrode plate facing the large housing surface at the outermost layer in order to separate the electrode plate from the housing;and wherein the separator comprises an inner layer section and an outer layer section connected to each other, the inner layer section being arranged between adjacent first and second electrode foils, the inner layer section covering a side of the first electrode foil at the second end facing the first end, and the tail end of the inner layer section being arranged between the first electrode foil at the second end and the adjacent second electrode foil, and wherein the inner layer section also comprising the head end, the head end at least partially covering the side surface of the first electrode foil located at the first end;wherein the outer layer section comprises a start end and a tail end, the start end being connected to the tail end of the inner layer section, and wherein the outer layer section extends in the direction of the first end along the stacking direction of the electrode plate and winds up the outside of the first electrode foil, the second electrode foil and the inner layer section, and covers one side of the first electrode foil facing the large housing surface at the second end, and wherein, in the stacking direction of the electrode plate, the length of the head end of the inner layer section is l, and wherein 0.1 mm ≤ 1 ≤ 5 mm. Battery according to claim 1, characterized in that the thickness of the separator T1 is, and wherein, 6 µm≤ T1≤400 µm. Battery according to claim 1, characterized in that the puncture resistance of the outer layer part is PPS, and wherein 200 kgf ≤ PPS ≤ 600 kgf applies. Battery according to claim 1, characterized in that the battery also comprises an insulating film, wherein the insulating film extends at least between the outer layer part and the housing in order to separate the separator from the housing. Battery according to claim 4, characterized in that the insulating film is glued to the outer layer part. Battery according to claim 1, characterized in that the overlap distance between the rear end and the head end of the outer layer section in the stacking direction of the electrode plates is m, and wherein 0.2 mm ≤ m ≤ 10 mm applies. Battery according to claim 1, characterized in that the first electrode foil is located in the outermost layer of the stack structure. Battery according to claim 1, characterized in that the separator is a continuously extending film extending from the inside of the stack structure to the outside of the stack structure and covering the outside of the stack structure, thereby separating the electrode plate from the housing. Battery according to claim 1, characterized in that the battery comprises at least two battery cells, wherein the two battery cells are arranged next to each other in the housing, and wherein the two adjacent battery cells are arranged along the stacking direction. Battery according to claim 9, characterized in that the battery cell has a first and a second end which are arranged opposite each other in the stacking direction of the electrode plates and the second ends of two adjacent battery cells are arranged opposite each other; and wherein, in the stacking direction of the electrode plates, the distance between the side of the battery cell at the first end and the electrode plate at the first end is greater than the distance between the side of the battery cell at the second end and the electrode plate at the second end. Battery according to claim 9, characterized in that the head end of the inner layer section covers the entire side surface of the first electrode foil at the first end. Battery according to claim 1, characterized in that the thickness of the battery cell Tbatterycell in the stacking direction of the electrode plate is Tbatterycell, and wherein 8 mm ≤ Tbatterycell ≤ 30 mm applies. Battery according to claim 1, characterized in that the battery cell comprises a tab, wherein the tab is electrically connected to the electrode plate, and wherein the width of the battery cell is Wbatterycell, wherein the width of the tab is Wtab, and then the two satisfy the condition 0.2 ≤ Wtab Wbatterycell ≤ 1 fulfill. Battery according to claim 1, characterized in that the battery comprises a pole and a tab, wherein the tab is electrically connected to the electrode plate, wherein the pole is arranged on the housing, and wherein one end of the pole is electrically connected to the tab and the other end is exposed on the surface of the housing. Battery according to claim 1, characterized in that the electrode plate comprises a current collector and an active substance layer, wherein the active substance layer is applied to the surface of the current collector. Battery according to claim 15, characterized in that the material of the current collector is aluminium when the electrode plate is a cathode foil, wherein the material of the active substance layer is lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. Battery according to claim 15, characterized in that the material of the current collector is copper if the electrode plate is an anode foil, wherein the material of the active substance layer is carbon or silicon. Battery according to claim 1, characterized in that the terminal end of the outer layer section extends towards the first end and overlaps at least partially with the initial end of the outer layer section. Battery according to claim 1, characterized in that the inner layer section covers the outside of the first electrode foil at the first end. Battery pack, characterized in that the battery pack comprises at least two batteries according to one of claims 1 to 17 and a conductive connecting element, wherein the two batteries are connected in series or in parallel via the conductive connecting element to establish an electrical connection. Battery pack, characterized in that the battery pack comprises an outer shell and at least two battery modules according to claim 18 or 20, wherein two battery modules are arranged in the outer shell, and wherein the two battery modules are electrically connected to each other.

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