Battery pack and electric vehicle

Abstract

Battery pack (200) for operating a vehicle, characterized in that it comprises: at least one battery unit (21), wherein the battery unit (21) comprises at least one battery string (1006), the battery string (1006) comprises a plurality of cells (100) and a voltage difference across the battery string (1006) is not more than about 60 V; and the multiple cells (100) in the battery string (1006) are arranged sequentially along a first direction, and the first direction is parallel to a direction from a rear of the vehicle to a front of the vehicle, where the length of the cells (100) extends along the first direction, wherein the battery unit (21) comprises a plurality of battery strings (1006), wherein the plurality of battery strings (1006) are arranged successively along a second direction, and wherein the second direction is a latitude direction of the vehicle and perpendicular to the first direction.

Description

AREA

[0001] The present utility model relates to the field of vehicle manufacturing technologies and in particular to a battery pack and an electric vehicle. BACKGROUND

[0002] In an electric vehicle, due to space constraints, the battery pack is typically mounted on the vehicle's underbody, i.e., the chassis. However, because the vehicle's underbody is relatively close to the ground, the underbody battery pack is extremely vulnerable to impacts while driving, which can cause a short circuit in one of the battery pack's cells. Specifically, when driving, the impact on the vehicle's underbody typically extends from the front to the rear, resulting in a short circuit affecting several cells within the battery pack.

[0003] As the power source for the electric vehicle, the battery pack has a high energy density. This high voltage and energy density also pose a significant risk. If a number of cells in the battery pack are short-circuited and a high voltage exists between them, a high-voltage breakdown or short circuit can occur immediately, potentially causing the battery pack to catch fire and explode. SUMMARY

[0004] The present utility model aims to solve at least one of the technical problems existing in the prior art. Accordingly, the present utility model provides a battery pack and an electric vehicle such that, in the event of a short circuit in a battery string, the voltage generated by the battery pack can be relatively reduced, which helps to prevent a high-voltage breakdown or a high-voltage short circuit of the battery pack, thereby improving the safety of the battery pack. The present utility model further provides an electric vehicle.

[0005] To achieve the aforementioned objective, the present utility model provides a battery pack for powering a vehicle, comprising at least one battery unit. The battery unit comprises at least one battery string. The battery string comprises one or at least two cells. The voltage difference across the battery string is less than or equal to 60 V. If the battery string comprises at least two cells, the cells in the battery string are arranged sequentially along a first direction, and this first direction is parallel to a direction from the rear of the vehicle to the front of the vehicle.

[0006] In some embodiments of the present utility model, the voltage difference across the battery string is less than or equal to 45 V.

[0007] In some embodiments of the present utility model, the voltage difference across the battery string is between 20 V and 40 V.

[0008] In some examples of the present utility model, the battery unit comprises several battery strings. The multiple battery strings are arranged sequentially along a second direction. The second direction is a width direction of the vehicle.

[0009] In some embodiments of the present utility model, the battery strings are connected in series and / or parallel.

[0010] In some embodiments of the present utility model, if the battery string comprises at least two cells, the at least two cells of the battery string are connected in series.

[0011] In some embodiments of the present utility model, the length of the cell extends along the first direction.

[0012] In some embodiments of the present utility model, the cell comprises a first pole and a second pole. The cell has two opposing first surfaces along the first direction. The first pole and the second pole are arranged on the same first surface of the cell or on the two first surfaces of the cell.

[0013] In some embodiments of the present utility model, the cell comprises a first pole and a second pole. The cell has a second surface facing the top of the vehicle. The first pole and the second pole are arranged on this second surface.

[0014] In some embodiments of the present utility model, several battery units are provided which are connected in series.

[0015] In some embodiments of the present utility model, the multiple battery units are arranged in an array to form a battery unit array. The battery unit array comprises multiple rows of battery unit groups. The multiple rows of battery unit groups are arranged sequentially along the first direction. An active safety device is connected between each pair of battery units that are arranged in two adjacent rows of battery unit groups and are electrically connected to each other.

[0016] In some embodiments of the present utility model, the active safety device is a relay or a fuse.

[0017] In some embodiments of the present utility model, the ratio between the length of the at least one cell and the length of the vehicle is between 0.2 and 0.8.

[0018] In some embodiments of the present utility model, the length of cell 100 ranges from 600 mm to 2500 mm.

[0019] The present utility model further provides for an electric vehicle that contains the aforementioned battery pack.

[0020] Compared to the related prior art, the present utility model has the following advantages: The battery pack of the present utility model comprises at least one battery unit. The battery unit comprises at least one battery string. The battery string comprises one or at least two cells. The voltage difference between the battery strings is less than or equal to 60 V. If the battery string comprises at least two cells, the cells in the battery string are arranged sequentially along a first direction, and the first direction is parallel to a direction from the rear of the vehicle to the front of the vehicle. Therefore, according to the above scheme, the voltage difference across the battery string formed by cells arranged in the direction from the rear of the vehicle to the front of the vehicle is relatively small.Therefore, even if a short circuit occurs in a cell in this direction after an impact while the vehicle is in motion, the impact of the short circuit on the battery pack is relatively small due to the cell's relatively low voltage. Consequently, the voltage generated by the battery pack when a short circuit occurs in the battery string can be relatively reduced, and a high-voltage breakdown or short circuit of the battery pack can be prevented. This reduces the likelihood of fire and explosion of the battery pack, and additionally, the occurrence of an arcing phenomenon can be reduced, thus improving the battery pack's safety.

[0021] Further aspects and advantages of the present utility model are partly evident from the following description, partly become apparent from the following description, or can be ascertained through the application of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic structure diagram of a battery pack according to an embodiment of the present utility model. Fig. Figure 2 is a schematic diagram of the effects on the cells in a battery pack after the underside of a vehicle has been struck by a hard object from the related area. Fig. Figure 3 is another schematic structure diagram of a battery pack according to an embodiment of the present utility model. Fig.Figure 4 is another schematic structure diagram of a battery pack according to an embodiment of the present utility model. Fig. Figure 5 is another schematic structure diagram of a battery pack according to an embodiment of the present utility model. Fig. Figure 6 is a schematic structure diagram of a cell according to an embodiment of the present utility model. Fig. Figure 7 is another schematic structure diagram of a battery pack according to an embodiment of the present utility model. Fig. Figure 8 is a schematic diagram of the impact on a cell in a battery pack after the underside of a vehicle has been struck by a hard object, according to an embodiment of the present utility model. Fig. Figure 9 is a cross-sectional view of a cell according to an embodiment of the present utility model. Fig.Figure 10 is a schematic representation of an electrode core arrangement encapsulated in an encapsulation film according to an embodiment of the present utility model. Fig. Figure 11 is a further schematic representation of an electrode core arrangement encapsulated in an encapsulation film according to an embodiment of the present utility model. Fig. Figure 12 is a schematic representation of a recess formed in a third surface of a metal housing according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0022] Embodiments of the present utility model are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein identical or similar elements or elements with identical or similar functions are designated by the same or similar reference numerals throughout the description. The embodiments described below with reference to the accompanying drawings are exemplary and serve only to illustrate the present utility model and are not to be understood as limiting the present utility model.

[0023] In describing this utility model, it should be understood that orientation or position relationships indicated by terms such as "center," "longitudinal," "transverse," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "above," "below," "inside," "outside," "axial," "radial," and "circumferential" are based on the orientation or position relationships shown in the accompanying drawings and are used only for the sake of simplicity and brevity in illustrating and describing this utility model. These terms do not imply that the device or component mentioned must have a specific orientation or be designed and operated in a specific orientation. Therefore, these terms should not be interpreted as limiting the scope of this utility model.

[0024] Referring to Fig.1. In one embodiment of the present utility model, a battery pack 200 can be used in an electric vehicle to supply the electric vehicle with energy. The electric vehicle can be, for example, a passenger car or a commercial vehicle, etc. The battery pack 200 comprises at least one battery unit 21. The battery unit 21 comprises at least one battery string 1006. The battery string 1006 comprises one or at least two cells 100. The voltage difference V between the battery strings 1006 is less than or equal to 60 V.

[0025] If the battery string 1006 comprises at least two cells 100, the cells 100 in the battery string 1006 are arranged sequentially along a first direction AB, and the first direction AB is parallel to a direction from the front of the vehicle to the rear of the vehicle.

[0026] A vehicle typically has three dimensions: length, width, and height. The length of the vehicle is defined as the distance between the rear and the front of the vehicle. The width of the vehicle is defined as the distance between the doors on the left and right sides. The height of the vehicle refers to the distance from the ground to the top of the vehicle. For most vehicles, the length is usually the largest dimension. Therefore, the first direction AB can be defined as the direction of the vehicle's length, i.e., the direction of its largest dimension.

[0027] In some embodiments, the battery unit 21 may contain only one battery string 1006. The battery string 1006 comprises several cells 100. The several cells 100 are arranged sequentially in the first direction AB. That is, all cells 100 in the battery unit 21 are arranged sequentially in the first direction. The cells 100 in the battery string 1006 can be connected in series. For example, adjacent cells 100 can be connected in series to realize the series connection of several cells. In this case, the voltage difference across the battery string 1006 is defined as the voltage difference across a series of cells connected in series.

[0028] In some other embodiments, the battery string 1006 may contain only one cell 100. In this case, the voltage difference across the battery string 1006 is defined as the voltage difference between the positive and negative electrodes of cell 100.

[0029] In a conventional battery pack, such as in Fig. As shown in Figure 2, a number of cells can be arranged in the battery pack to maximize battery capacity. If a number of cells are arranged along the direction from the rear of the vehicle to the front (the first direction AB), the impact on the underside of the vehicle typically occurs from the front to the rear. Therefore, all the cells (the cells in the shaded area in the figure) arranged in the battery pack from the front to the rear of the vehicle can deform and break together when the underside of the vehicle is struck by a hard object G while driving. As a result, a short circuit occurs in a row of cells, the battery pack generates a higher voltage, and the battery is prone to catching fire and exploding.

[0030] In the embodiment of the present utility model, the voltage difference V across the battery string 1006 does not exceed 60 V. This means that the voltage difference across the battery string, which is formed by the cells arranged in the direction from the rear of the vehicle to the front, is relatively small. Therefore, even if a short circuit occurs in all cells 100 of the battery string 1006, which is arranged in the direction from the front of the vehicle to the rear, during the operation of the vehicle, it is a low-voltage short circuit because the voltage of the battery string 1006 is relatively low. This means that the voltage generated by the battery pack can be relatively low in the event of a short circuit in the battery string 1006.Therefore, a high-voltage breakdown or a high-voltage short circuit of the battery pack can be prevented, thereby reducing the likelihood of fire and explosion of the battery pack, and furthermore, the occurrence of an arcing phenomenon can be reduced to effectively prevent thermal runaway and thermal propagation between the cells, thus improving the safety of the battery pack.

[0031] Furthermore, the voltage difference between the battery strings 1006 is kept so that it does not exceed 60 V, thus reducing the occurrence of an arc and improving the energy storage capacity of the battery pack as much as possible.

[0032] Furthermore, the voltage difference V across the battery string 1006 is less than or equal to 45 V. The voltage difference V across the battery string 1006 is kept relatively low so that the effects on the battery pack can be further reduced in the event of a short circuit in the battery string 1006. This prevents problems such as battery pack failure due to high voltage generated by the battery pack during a short circuit, thus preventing the occurrence of an arcing phenomenon. The voltage difference V across the battery string 1006 can range between 20 V and 40 V.

[0033] Through a large number of arc flash tests, it was determined that, provided the battery capacity is increased as much as possible, the voltage difference across the battery string 1006, formed by all cells arranged along the vehicle's direction of travel (which can also be understood as the direction from the front of the vehicle to the rear), does not exceed 60 V and the battery pack can be effectively protected from fire. The test data are listed in the following table: Voltage difference 10V 45 V 60 V 80 V Experimental result No arcing. Safety requirements are met. Slight arcing, no fire, no smoke. Safety requirements are met. No arcs, no fire, no smoke. Safety requirements are met. Obvious arcing, fire, smoke. Safety requirements are not met.

[0034] The above test data show that the battery pack does not catch fire and does not produce smoke if the voltage difference between the battery strings does not exceed 1006 60 V, so that the performance requirements can be met and the safety performance of the battery pack can be improved.

[0035] The arc flash testing experiments can be performed using an existing arc flash testing method. In the test, the voltage difference across the battery string was varied, and then the test vehicle was driven on the test track with obstacles to observe any fire or smoke from the battery pack.

[0036] Referring to Fig. 3 In one embodiment of the present utility model, the battery unit 21 comprises several battery strings 1006. The several battery strings 1006 are arranged sequentially along a second direction CD. The second direction CD is a width direction of the vehicle. The voltage difference V between the individual battery strings 1006 is less than or equal to 60 V. For example, the voltage difference between the individual battery strings 1006 can be 45 V or 50 V.

[0037] The number of cells in the battery string 1006 is not explicitly limited. The number can be, for example, 4 or 6, provided that the voltage difference between the battery strings 1006 does not exceed 60 V.

[0038] The 100 cells of the same battery string 1006 are connected in series. The battery strings 1006 can be connected in parallel or in series, or in both series and parallel. For example, adjacent battery strings 1006 are connected in series. Alternatively, two battery strings 1006 can be connected in parallel and then connected in series with another battery string 1006, although this is not explicitly excluded.

[0039] As in Fig.As shown in Figure 4, one embodiment of the present utility model provides several battery units 21 connected in series. In particular, each battery unit 21 comprises a first electrode output end 211 and a second electrode output end 212 for drawing current. The first electrode output end 211 of one battery unit 21 and the second electrode output end 212 of the other battery unit 21 in two adjacent battery units 21 are electrically connected, thereby creating a series connection.

[0040] The multiple battery units 21 are arranged in an array to form a battery unit array. The battery unit array comprises multiple rows of battery unit groups 201. The multiple rows of battery unit groups 201 are arranged sequentially along the first direction AB. It can also be assumed that each row of cell groups 202 comprises multiple battery units arranged sequentially along the first direction AB. As in Fig. As shown in Figure 4, the battery unit array can contain only one column of battery unit groups 202. Alternatively, the battery unit array can be configured as shown in Figure 4. Fig.Figure 5 shows several columns of battery unit groups 202. The several columns of battery unit groups 202 are arranged consecutively along the second direction CD. The two adjacent battery units 21 in the same row of battery unit groups 201 are connected in series. Two adjacent rows of battery unit groups 201 are also connected in series. The two adjacent rows of battery unit groups are electrically connected by an active safety device 22.

[0041] The active safety device 22 is connected between two battery units 21, which are arranged in two adjacent rows of battery unit groups 201 and are electrically connected to each other.

[0042] As in Fig.As shown in Figure 4, each row of battery unit groups has a battery unit 21. Therefore, in the two battery units 21 of the two adjacent rows of battery unit groups, the first electrode output end 211 of one battery unit 21 and the second electrode output end 212 of the other battery unit 21 are electrically connected by the active safety device 22. The active safety device 22 includes, among other things, a relay, a fuse, or another control switch. The active safety device 22 is used to automatically interrupt the connection between the two adjacent rows of battery units when the current between the two adjacent rows of battery units is too high. In the embodiment of Fig.1 The active safety device is used to interrupt the electrical connection between the two adjacent battery units 21 when the current between the two adjacent battery units 21 is relatively large.

[0043] If several battery units 21 in the same row have short-circuited cells, a high-voltage circuit inevitably forms between the battery units 21, and the current in the circuit increases. The active safety device 22 is arranged between the two adjacent rows of battery unit groups, so that the connection between the two rows of battery units is interrupted when a short circuit occurs, thereby further improving the safety of the battery pack.

[0044] Referring to Fig. 6 and in connection with Fig.In one embodiment of the present utility model, cell 100 is approximately a cuboid. The length of cell 100 extends along the first direction AB. Cell 100 comprises a first pole 1001 and a second pole 1002. The polarities of the first pole 1001 and the second pole 1002 are opposite in order to draw a current. For example, the first pole 1001 is a positive terminal and the second pole 1002 is a negative terminal.

[0045] Cell 100 has two opposing first surfaces 1003 in the first direction AB. The first pole 1001 and the second pole 1002 are arranged on the same first surface 1003 of cell 100 or can be arranged on both first surfaces 1003.

[0046] For a battery unit 21, if several cells 100 are provided in the battery unit 21 and the several cells 100 are arranged to form several rows of cell groups, the several rows of cell groups are arranged sequentially along the second direction CD. In one embodiment of the present utility model, the length of the cell 100 extends along the first direction AB, and the multiple cells are arranged along the second direction CD, so that the number of cells susceptible to damage when the vehicle floor is struck can be reduced. As in Fig.As shown in Figure 8, several cells are arranged along the second direction CD. If the underside of the vehicle is struck by a hard object G during operation, the number of cells affected by the impact (the cells in the shaded area of ​​the figure) can be reduced, thus preventing damage to the cells throughout the battery pack. Therefore, this embodiment further improves the safety of the battery pack.

[0047] In other embodiments, such as in Fig. 7 and in connection with Fig. As shown in Figure 6, the first pole 1001 and the second pole 1002 of the cell 100 can be arranged on other surfaces of the cell. In particular, the cell 100 has a second surface 1004 facing the top of the vehicle. The first pole 1001 and the second pole 1002 are arranged on the second surface 1004.

[0048] The cell 100 has two opposing second surfaces 1004 in a third direction EF. The third direction EF is the direction from the underside of the vehicle to the top of the vehicle. The first rod 1001 and the second rod 1002 can be arranged on the second surface 1004 that faces the top of the vehicle of the cell 100.

[0049] It should be noted that the first terminal of cell 100 at one end of battery string 1006 is pulled out by a wire that corresponds to the first electrode output 211 of battery unit 21. The second terminal of cell 100 at the other end of the battery string is pulled out by a wire that corresponds to the second electrode output 212 of battery unit 21.

[0050] In one embodiment of the present utility model, the ratio between the length of cell 100 and the length of the vehicle is in the range of 0.2 to 0.8. In one embodiment of the present utility model, the length L of cell 100 ranges from 600 mm to 2500 mm. The length L can be, for example, 600 mm, 1200 mm, or 2000 mm. If the length dimension of cell 100 lies within this range, the overall structure of cell 100 corresponds more closely to a standardized design that can be used universally in various battery packs 200 to achieve a wide range of applications. The thickness of cell 100 extends along the second direction CD (i.e., the width direction of the vehicle), and the thickness H of cell 100 can be greater than 10 mm. For example, the thickness H can be between 13 mm and 75 mm.

[0051] More precisely, by jointly referring to Fig. 6 to Fig.The cell 100 comprises a metal housing 11 and several electrode core assemblies 12, which are encapsulated in the metal housing 11 and arranged sequentially along the first direction AB. The several electrode core assemblies 12 can be connected in series to form an electrode core string. Each electrode core assembly 12 contains at least one electrode core.

[0052] The electrode core assembly 12 comprises a first electrode 121 and a second electrode 122 for conducting a current. Furthermore, the electrode core assembly 12 includes an electrode core assembly main body 123 and the first electrode 121 and the second electrode 122, which are electrically connected to the electrode core assembly main body 123. The first electrode 121 and the second electrode 122 are each arranged on opposite sides of the electrode core assembly main body 123 along the first direction AB. In two adjacent electrode core assemblies 12, the first electrode 121 of one electrode core assembly 12 and the second electrode 122 of the other electrode core assembly 12 are electrically connected to form a series connection. Since several electrode core assemblies 12 are connected in series, the capacity and voltage can be improved by using a single cell 100, the manufacturing process can be simplified, and the manufacturing costs can be reduced.

[0053] It should be noted that the series connection in this embodiment can be a series connection between the two adjacent electrode core assemblies 12. In a special embodiment, the first electrodes 121 and the second electrodes 122 can be directly connected to the two adjacent electrode core assemblies 12 or electrically connected by an additional conductive component. If the electrode core assembly 12 comprises only one electrode core, the first electrode 121 and the second electrode 122 can be a positive and a negative tab of the electrode core, respectively. If the electrode core assembly 12 comprises multiple electrode cores, the connection components of the first electrode 121 and the second electrode 122 can be electrode leads.The "first" and "second" in the first electrode 121 and the second electrode 122 are used only to distinguish the designations and not to limit the number. The first electrode 121 and the second electrode 122 can, for example, comprise one or more electrodes.

[0054] Furthermore, the metal housing 11 comprises a housing body 111, which is provided with an opening and a cover plate 112. The cover plate 112 is hermetically connected to the opening of the housing body 11 to jointly form a sealed receiving chamber. The electrode core string, which is formed by several electrode core assemblies 12 connected in series, is housed in the receiving chamber. A first electrode and a second electrode are provided at each end of the electrode core string. The first electrode of the electrode core string is the first electrode 121 of the electrode core assembly 12, which is arranged at one end of the electrode core string. The second electrode of the electrode core string is the second electrode 122 of the electrode core assembly 12, which is arranged at the other end of the electrode core string.

[0055] In some embodiments, the first electrode and the second electrode, which are arranged at both ends of the electrode core string, are pulled out of the cover plate 112, so that the first pole 1001 and the second pole 1002 of the cell 100 are formed.

[0056] In particular, in some embodiments, the housing body 111 can be provided with two openings at both ends, and two cover plates 112 can be provided, such that the two cover plates 112 are hermetically connected to the two openings at both ends of the housing body 111 to jointly form a sealed receiving chamber. In this embodiment, the first electrode and the second electrode, which are arranged at both ends of the electrode core string, can each be pulled out of the two cover plates 112, thus forming the first pole 1001 and the second pole 1002 of the cell 100, respectively. The first pole 1001 and the second pole 1002 are each arranged on the first surface 1003 of the cell 100 at both ends in the first direction AB.Of course, in other embodiments, the first electrode and the second electrode, which are arranged at both ends of the electrode core string, can be pulled out of the same cover plate 112, so that the first pole 1001 and the second pole 1002 of the cell 100, respectively, are formed. The first pole 1001 and the second pole 1002 are each arranged on the first surface 1003 of the cell 100 at the same end in the first direction AB.

[0057] In some other embodiments, the housing body 111 may be provided with an opening at only one end, and a cover plate 112 may be provided such that the cover plate 112 is hermetically connected to the opening at one end of the housing body 111. In this embodiment, the first electrode and the second electrode, which are arranged at both ends of the electrode core string, are pulled out of the same cover plate 112, thus forming the first pole 1001 and the second pole 1002 of the cell 100. The first pole 1001 and the second pole 1002 are each arranged at the same end of the cell 100.

[0058] It can be assumed that in other embodiments, the first and second electrodes, which are arranged at both ends of the electrode core string, cannot be pulled out of the cover plate 112. The cover plate 112 is provided with the first pole 1001 and the second pole 1002. Furthermore, a first electrode connection and a second electrode connection can both be arranged on the same cover plate 112 or on two cover plates 112. In this case, the first and second electrodes, which are arranged at both ends of the electrode core string, are each electrically connected to the first and second electrode connections on the cover plate 112, respectively, which is not described in detail here.

[0059] It should be noted that the electrode core assemblies 12 can be connected both in series and in parallel. For example, the electrode core assemblies 12 can form two electrode core strings. In particular, the electrode core assemblies 12 can be divided into two parts. The electrode core assemblies 12 in each part are connected in series to form one electrode core string, and the two electrode core strings are connected in parallel. Of course, the multiple electrode core assemblies 12 can also be divided into three or more parts. The electrode core assemblies 12 in each part are connected in series to form one electrode core string, and multiple electrode core strings are connected in parallel. It can be assumed that the multiple electrode core assemblies 12 in cell 100 are divided into multiple parts.The multiple electrode core assemblies 12 in each part are connected in series to form an electrode core string, so that each electrode core string can have a specific voltage to meet the operating requirements. Multiple electrode core strings are connected in parallel so that the capacitances of the multiple electrode core strings can be added to give the cell 100 a larger capacity, which helps to extend the power supply time of the cell 100.

[0060] In one embodiment of the present utility model, an encapsulation film 13 is further provided between the metal housing 11 and the electrode core assembly 12. That is, the electrode core assembly 12 is encapsulated within the encapsulation film 13. In this way, secondary encapsulation of the electrode core assembly 12 can be achieved by using the encapsulation film 13 and the metal housing 11, which contributes to improving the sealing effect of the cell 100. It can be assumed that the encapsulation film 13 is also injected with an electrolyte solution. Therefore, contact between the electrolyte solution and the metal housing 11 can be avoided, and corrosion of the metal housing 11 or decomposition of the electrolyte solution can be prevented.

[0061] The air pressure between the metal housing 11 and the encapsulation film 13 is lower than that outside the metal housing 11. The air pressure inside the encapsulation film 13 is lower than that between the metal housing 11 and the encapsulation film 13.

[0062] In the present utility model, "pressure" is the abbreviation for atmospheric pressure. Atmospheric pressure is defined as the atmospheric pressure acting on a unit area that corresponds to the weight of a vertical column of air extending upwards over a unit area to the upper boundary of the atmosphere.

[0063] The air pressure between the metal housing 11 and the encapsulation film 13 is the air pressure in the space between the metal housing 11 and the encapsulation film 13. The air pressure is lower than that outside the metal housing 11. Therefore, in one embodiment of the present utility model, the metal housing 11 and the encapsulation film 13 are in a state of negative pressure.In this way, the metal housing 11 is indented or deformed under the influence of atmospheric pressure, and a gap between the metal housing 11 and the electrode core assembly 12 is reduced accordingly, the space for the movement of the electrode core assemblies 12 or the displacement between them is reduced, so that the movement of the electrode core assemblies 12 and a relative displacement between the electrode core assemblies 12 can be reduced, thereby improving the stability of the cell 100, the strength of the cell 100 and the safety performance of the cell 100.

[0064] For example, the space between the metal housing 11 and the encapsulation film 13 can be vented, creating a vacuum in this space. This allows the metal housing 11 and the internal electrode core assembly 12 to be positioned as close together as possible, minimizing internal gaps and preventing electrode core movement within the metal housing. Relative displacement between the electrode cores is prevented, reducing current collector damage, diaphragm wrinkling, and active material shedding. This improves the overall mechanical strength of the cell 100, extends its service life, and enhances its safety performance.

[0065] In one embodiment, the air pressure between the metal housing 11 and the encapsulation film 13 is P1. The value of P1 can be in the range of -100 kPa to -5 kPa. More preferably, the value of P1 can be between -75 kPa and -20 kPa. Of course, a person skilled in the art can adjust the value of P1 according to the actual requirements. It should be noted that the space between the metal housing 11 and the encapsulation film 13 can be in a vacuum.

[0066] Furthermore, the air pressure in the encapsulation film 13 is equal to P2. The value of P2 can be between -100 kPa and -20 kPa.

[0067] The ratio between P1 and P2 satisfies the condition P1 > P2. A ratio between P1 and P2 ranges from 0.05 to 0.85.

[0068] The values ​​of P1, P2, and the ratio between P1 and P2 are limited to the aforementioned ranges. The electrode core assembly 12 in the present technology adopts a secondary encapsulation mode. The electrode core assembly 12 of a battery is first encapsulated in the encapsulation layer 13. To prevent damage to the encapsulation layer 13 if excessive internal atmospheric pressure causes it to bulge outwards, the atmospheric pressure between the metal casing 11 and the encapsulation layer 13 is chosen to be greater than the atmospheric pressure within the encapsulation layer 13. Numerous experiments have shown that the reliability of the secondary encapsulation of the cell 100 is better ensured when the ratio between P1 and P2 is within the aforementioned range.An interface between the pole shoes of cell 100 is ensured, and a gap between the pole shoes is avoided to allow better conduction of the lithium ions.

[0069] In one embodiment of the present utility model, an encapsulation layer 13 is included. The series-connected electrode core assemblies 12 are encapsulated in the same encapsulation layer 13. A connection between the first electrode 121 of one of the two series-connected electrode core assemblies 12 and the second electrode 122 of the other electrode core assembly 12 is arranged in the encapsulation layer 13. That is, the encapsulation layer 13 is integrally arranged, and the multiple electrode core assemblies 12 are encapsulated in the same encapsulation layer 13.

[0070] In practical applications, for example, as in Fig.As shown in Figure 10, several electrode core assemblies 12 are first connected in series, and then a whole section of encapsulation layer 13 is used to encapsulate the series-connected electrode core assemblies 12. For example, the series-connected electrode core assemblies 12 can be placed on a portion of the encapsulation layer 13 (or a recess can be pre-formed in a portion of the encapsulation layer 13, and then the several series-connected electrode core assemblies 12 can be arranged in the recess), the other portion of the encapsulation layer 13 is folded towards the electrode core assemblies 12, and then the encapsulation layer 13 is melted and sealed in the two parts by hot melting. Therefore, the series-connected electrode core assemblies 12 are encapsulated in the same encapsulation layer 13.

[0071] In the encapsulation layer 13, an encapsulation section 131 is formed at a location opposite the first electrode 121 and / or the second electrode 122 in order to insulate two adjacent electrode core assembly main bodies 123. At least one of the first electrode 121 of one electrode core assembly 12 and one of the second electrode 122 of the other electrode core assembly 122 in the two adjacent electrode core assemblies 12 is arranged in the encapsulation section 131.Several electrode core assembly main bodies 123 are isolated by the encapsulation section 131 to prevent mutual circulation of electrolyte solutions of the several electrode core assemblies 12, thus preventing the several electrode core assemblies 12 from influencing each other and preventing the electrolyte solutions in the several electrode core assemblies 12 from decomposing due to an excessively large potential difference, thereby ensuring the safety and lifetime of the cell 100.

[0072] The encapsulation section 131 can be designed in various ways. For example, the encapsulation layer 13 can be attached with a band to form the encapsulation section 131, or the encapsulation layer 13 can be directly thermally fused and joined to form the encapsulation section 131. Alternatively, a separating plate can be placed directly between the two electrode core assemblies 12 to form the encapsulation section 131. The manner in which the encapsulation section 131 is designed is not particularly limited.

[0073] In another embodiment of the present utility model, as in Fig. Figure 11 shows several encapsulation layers 13. At least one electrode core assembly 12 is encapsulated in an encapsulation layer 13 to form an electrode core assembly. Several electrode core assemblies are connected in series.

[0074] In other words, the encapsulation layers 13 correspond one-to-one to the electrode core assemblies 12. Each electrode core assembly 12 is separately encapsulated in an encapsulation layer 13. In this embodiment, after the preparation of the multiple electrode core assemblies 12 is complete, an encapsulation layer 13 can be applied separately outside each electrode core assembly 12, and then the multiple electrode core assemblies are connected in series.

[0075] At least one of the first electrode 121 and the second electrode 122 of the electrode core assembly 12 protrudes from the encapsulation layer 13. For example, the first electrode 121 may protrude from the encapsulation layer 13, or the second electrode 122 may protrude from the encapsulation layer 13, or both the first electrode 121 and the second electrode 122 may protrude from the encapsulation layer 13. The extended electrodes can be connected in series with other electrode core assemblies by means of at least one of the first electrodes 121 and / or the second electrode 122 protruding from the encapsulation layer 13.

[0076] In one embodiment of the present utility model, the arrangement direction of the multiple electrode core assemblies 12 is the first direction AB. A longitudinal direction of the electrode core assemblies 12 extends along the first direction AB. The length of the cell 100 also extends in the first direction AB. That is, the multiple electrode core assemblies 12 are arranged successively along a longitudinal direction of the cell 100, and the first electrodes 121 and the second electrodes 122 of the electrode core assemblies 12 are each arranged on both sides of the electrode core assemblies 12 along the first direction AB. Thus, the multiple electrode core assemblies 12 assume a "head-to-head" arrangement, so that the electrode core assemblies 12 can be conveniently connected in series in pairs, and the connection structure is simple. Furthermore, this arrangement can facilitate the manufacture of a cell 100 with a greater length.When cell 100 is installed in a battery pack housing, it may therefore not be necessary to provide support structures such as beams and longitudinal members. Instead, cell 100 is mounted directly onto the battery pack housing, using the metal casing 11 of cell 100 as a support. This saves space within the battery pack, improves volume utilization, and reduces the battery pack's weight.

[0077] In cell 100, several electrode core assemblies 12 are arranged, allowing for the more convenient production of longer cell 100s compared to an existing method using only one electrode core. In a conventional battery, the length of the copper-aluminum foil used as the internal current collector can increase accordingly, leading to a significant rise in the battery's internal resistance. This makes it impossible to meet the current requirements for increasingly higher power output and rapid charging when the battery is longer. For the same battery length, the embodiment of the present utility model can significantly reduce the battery's internal resistance and avoid problems caused by battery overheating during high power output, rapid charging, and similar operations.

[0078] As in Fig.As shown in Figure 12, the metal housing 11 has two opposing third surfaces 1005 along the second direction CD. The third surface 1005 is the largest surface of the cell 100, i.e., the "large surface" of the cell 100. At least one third surface 1005 is embedded in the metal housing 11 so that the metal housing 11 and the electrode core assembly 12 fit together as closely as possible.

[0079] The metal housing 11 has a relatively small thickness and is made of thin sheet metal. Therefore, a recess 114 in the third surface 1005 of the metal housing 11 could, for example, be a recess that forms when air is extracted from the inside of the metal housing 11. That is, if the air extraction is carried out in the space between the metal housing 11 and the encapsulation layer 13 to make the air pressure between the metal housing 11 and the encapsulation layer 13 lower than that outside the metal housing 11, the third surface 1005 of the metal housing 11 will likely form the recess 114 in the metal housing 11 as the air extraction progresses.

[0080] During normal use of the Cell 100, the cell typically expands due to material expansion, electrolyte gas production, and similar factors. The area of ​​greatest expansion and deformation often occurs on the cell's large surface area. This technology limits this large surface area to a slight inward depression created by a vacuum during the battery's initial state. This effectively relieves pressure between the cells as they expand, thereby improving the lifespan, safety, and overall performance of both the battery and the entire system.

[0081] In some other embodiments, such as in Fig.As shown in Figure 12, air extraction can be carried out on the inside of the metal housing 11 after a recess has been formed in the third surface 1005 of the metal housing 11. Several recesses 114 can be provided in the third surface 1005 of the metal housing 11. For example, the several recesses 114 in the third surface 1005 are formed in advance, and the position of each recess 114 corresponds to the position of an electrode core assembly 12.

[0082] In some embodiments, two opposing third surfaces 1005 of the metal housing 11 are both recessed inwards, so that the electrode core assembly 12 can be clamped by the recessed areas.

[0083] The metal housing 11 may have a vent opening, and the space between the metal housing 11 and the encapsulation layer 13 is vented through this opening. The vent opening must be sealed. Therefore, a sealing element is provided in the vent opening to seal it. This sealing element could be, for example, a plug or a rubber element, but this is not limited.

[0084] In some embodiments, a gap is provided between the electrode core assembly 12 and an inner surface of the metal housing 11 before the metal housing 11 is vented. This gap facilitates easy installation of the electrode core assembly 12 in the metal housing 11. After the metal housing 11 is vented, it is pressed against an outer surface of the electrode core assembly 12 in a second direction to clamp the assembly, thereby reducing the space available for movement of the electrode core assembly 12 within the metal housing 11 and improving the safety performance of the cell 100.

[0085] In one embodiment of the present utility model, the metal housing 11 has high strength and good heat dissipation. The metal housing 11 can be made of aluminum or steel, but is not limited to either. In some embodiments, the thickness of the metal housing 11 is between 0.05 mm and 1 mm.

[0086] A thicker metal casing 11 increases the weight of the cell 100 and reduces its capacity. If the metal casing 11 is too thick, it cannot be easily pressed or deformed towards the side of the electrode core assembly 12 under the influence of atmospheric pressure. Therefore, the distance between the metal casing 11 and the electrode core assembly 12 cannot be reduced, and the positioning function of the electrode core assembly 12 cannot be effectively implemented. Furthermore, if the metal casing 11 is excessively thick, the cost of air extraction increases, leading to a rise in manufacturing costs.

[0087] In the present utility model, the thickness of the metal housing 11 is limited to the aforementioned range, thus ensuring the strength of the metal housing 11 and preventing a reduction in the capacity of the cell 100. Furthermore, the metal housing 11 can be more easily deformed under vacuum to reduce the distance between the metal housing 11 and the electrode core assembly 12, thereby reducing the movement of the electrode core assemblies 12 within the metal housing 11 and the relative displacement between the electrode core assemblies 12.

[0088] In one embodiment of the present utility model, the encapsulation layer 13 comprises a laminated non-metallic outer layer film and a non-metallic inner layer film. The inner layer film is arranged between the outer layer film and the electrode core assembly 12.

[0089] The inner layer film has good chemical stability. Materials with corrosion protection properties against electrolyte solutions, such as polypropylene (PP), polyethylene (PE), or polyethylene terephthalate (PET), can be used, or a combination of the above-mentioned materials.

[0090] The outer layer film is a protective layer, and its use can prevent the permeation of air, especially water vapor, oxygen, and the like. The material of the outer layer film can be, for example, polyethylene terephthalate, polyamide (PA), or polypropylene, or a combination of the aforementioned materials.

[0091] In the encapsulation layer 13 of this embodiment, the melting point of the outer film layer is higher than that of the inner film layer. This prevents the outer film layer from melting during hot melt sealing, allowing the inner film layer to melt in time to ensure excellent sealing performance. Furthermore, the melting point difference between the outer and inner film layers is between 30°C and 80°C. For example, the melting point difference between the two could be 50°C, 70°C, or a similar value. The specific material selection can be determined according to the actual requirements.

[0092] The non-metallic outer film layer and the non-metallic inner film layer are bonded and joined together by an adhesive. The outer film layer can be made of, for example, a multi-layer material, and the inner film layer can be made of PET. The adhesive used to bond the two layers can be, for example, a polyolefin adhesive, to form a composite film.

[0093] In this embodiment, the electrode core assembly 12 is encapsulated by forming the encapsulation layer 13 from a two-layer non-metallic foil. Since the non-metallic encapsulation layer 13 has higher tensile strength and elongation at break, the thickness limitation of the cell 100 can be reduced, and the manufactured cell 100 can have a greater thickness. The thickness of the cell 100 can be increased over a wide range in this embodiment. For example, the thickness can be more than 10 mm, e.g., between 13 mm and 75 mm.

[0094] In some embodiments of the present utility model, the encapsulation layer 13 can be an aluminum-plastic foil.

[0095] In one embodiment of the present utility model, cell 100 is a lithium-ion battery.

[0096] In one embodiment of the present utility model, a gap is provided between two adjacent cells 100 in one and the same battery unit 21 between the cells arranged consecutively in the second direction CD. The ratio of the gap to the thickness of the cell 100 is in the range of 0.001 to 0.15.

[0097] It should be noted that the distance between the two adjacent batteries may vary as the batteries' operating time increases. However, during or after battery operation, or before the batteries leave the factory, the distance falls within the scope of protection of this utility model, provided that the ratio between the distance between the batteries and the thickness is within the range defined in this utility model.

[0098] In the present utility model, a specific gap is provided between the cells 100 in order to reserve a buffer space for the expansion of the cells 100.

[0099] The expansion of cell 100 is related to its thickness. A greater thickness increases the cell's tendency to expand. In the present utility model, the ratio between the spacing of cells 100 and their thickness is limited to a range of 0.001 to 0.15, thus fully utilizing the space within battery pack 200, thereby improving the battery pack's capacity utilization and providing better buffering against cell expansion.

[0100] Furthermore, heat can be generated when cell 100 expands. If a certain distance is maintained between the cells 100, this space can be used as a heat dissipation channel, similar to an air duct. A larger surface area of ​​cell 100 provides better heat dissipation, thus improving the heat dissipation efficiency of the battery pack 200 and consequently enhancing its safety performance.

[0101] In the above solution, the space between the cells 100 can be understood to mean that no structural element is provided between the cells 100, but rather that a specific space is merely reserved. It can also be understood to mean that the cells 100 are equipped with another structural element, such that cell 100 is separated from cell 100 by this structural element.

[0102] It should be noted that if a structural element is provided between the cells 100, the gap between the cells 100 is to be understood as the distance between the cells 100 on both sides of the structural element, but cannot be understood as the distance between the structural element and the cell 100.

[0103] It should be noted that a special gap can be reserved between the structural element and the cells 100 on both sides of the structural element, or that the structural element is in direct contact with the cells 100 on both sides. If the structural element is in direct contact with the cells 100 on both sides, it exhibits a special flexibility to provide a buffer for the expansion of the cells 100. The structural element may include, among other things, an aerogel, a thermally conductive structural adhesive, or heat-insulating cotton.

[0104] The present utility model further provides an electric vehicle with the aforementioned battery pack 200. The electric vehicle and the aforementioned battery pack 200 have the same advantages compared to related technologies. Details are not described again here.

[0105] In the description of this utility model, it should be noted that, unless otherwise specified and limited, terms such as "installation," "interconnection," and "connection" are to be understood in a broad sense. For example, the connection may be a fixed connection, a detachable connection, or an integral connection; or the connection may be a mechanical connection or an electrical connection; or the connection may be a direct connection, an indirect connection via an intermediary, or an internal connection between two elements. The specific meanings of the aforementioned terms in this utility model can be understood by those skilled in the art depending on the specific situations.

[0106] In the description of this specification, the description of reference terms such as "elaboration," "specific embodiment," and "example" means that the specific features, structures, materials, or properties described with reference to the embodiment or example are included in at least one embodiment or example of the present utility model. In this description, exemplary descriptions of the aforementioned terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or properties may be appropriately combined in one or more of the embodiments or examples.

[0107] Although the embodiments of the present utility model have been shown and described, a person skilled in the art can understand that changes, alternatives and modifications to the embodiments can be made without deviating from the principle and purpose of the present utility model, and the scope of the present utility model is defined by the claims.

Claims

[1] Battery pack (200) for operating a vehicle, characterized by , that it comprises: at least one battery unit (21), wherein the battery unit (21) comprises at least one battery string (1006), the battery string (1006) comprises a plurality of cells (100), and the voltage difference across the battery string (1006) is not more than about 60 V; and the multiple cells (100) in the battery string (1006) are arranged sequentially along a first direction, and the first direction is parallel to a direction from a rear of the vehicle to a front of the vehicle, where the length of the cells (100) extends along the first direction, wherein the battery unit (21) comprises a plurality of battery strings (1006), wherein the plurality of battery strings (1006) are arranged successively along a second direction, and wherein the second direction is a latitude direction of the vehicle and perpendicular to the first direction. [2] Battery pack (200) according to claim 1, characterized by , that the voltage difference across the battery string (1006) is no more than approximately 45 V. [3] Battery pack (200) according to claim 2, characterized by , that the voltage difference across the battery string (1006) is in the range of approximately 20 V to approximately 40 V. [4] Battery pack (200) according to claim 1, characterized by that the battery strings (1006) are connected in series and / or parallel. [5] Battery pack (200) according to claim 1, characterized by, that if the battery string (1006) comprises at least two cells (100), the at least two cells (100) in the battery string (1006) are connected in series. [6] Battery pack (200) according to claim 1, characterized by , that the cell (100) comprises a first pole and a second pole, the cell (100) has a second surface facing a top of the vehicle, and the first pole and the second pole are arranged on the second surface. [7] Battery pack (200) according to claim 1, characterized by , that a plurality of battery units (21) is provided, and the plurality of battery units (21) is connected in series. [8] Battery pack (200) according to claim 7, characterized by, that the multiple battery units (21) are arranged in an array to form a battery unit array, the battery unit array comprising multiple rows of battery unit groups (201) arranged sequentially along the first direction, and an active safety device (22) is connected between each pair of battery units (21) arranged in two adjacent rows of battery unit groups (201) and electrically connected to each other. [9] Battery pack (200) according to claim 8, characterized by that the active safety device (22) is a relay or a fuse. [10] Electric vehicle, characterized by , that it comprises the battery pack (200) according to any one of claims 1 to 9.

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