Battery cell and battery pack

Abstract

The utility model relates to battery technology field discloses a kind of battery monomer and battery package, battery monomer includes: shell, enclosed formation containing cavity, shell includes bottom wall, bottom wall is located at the bottom of shell along gravity direction;The side surface of bottom wall towards containing cavity is inner bottom surface, and the height difference H1 of two ends along the first direction exists in inner bottom surface, unit is mm, satisfy: 0.5≤H1≤10;Wherein, the first direction is perpendicular to gravity direction.The battery monomer provided by the utility model, by making the height difference H1 of two ends along the first direction exist in inner bottom surface, thereby reducing the volume of gap region, prompting electrolyte to be less accumulated in shell bottom, more in other areas of containing cavity, ensure that each part of battery is evenly infiltrated, improve battery performance.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery cell and a battery pack. Background Technology

[0002] After the battery is assembled, it needs to be injected with electrolyte. This involves injecting electrolyte into the battery casing to ensure that the cells are fully wetted, thereby ensuring the normal operation of the battery.

[0003] In related technologies, there is often a situation where there is a large amount of residual electrolyte at the bottom of the battery casing, which can easily lead to poor cell wetting effect. Utility Model Content

[0004] In view of this, the present invention provides a battery cell and a battery pack to solve the problem of poor cell wetting effect caused by excessive electrolyte residue at the bottom of the battery casing.

[0005] In a first aspect, this utility model provides a battery cell, comprising:

[0006] The shell encloses and forms a receiving cavity, and the shell includes a bottom wall located at the bottom of the shell along the direction of gravity;

[0007] The side surface of the bottom wall facing the receiving cavity is the inner bottom surface. There is a height difference H1 between the two ends of the inner bottom surface along the first direction, in mm, which satisfies: 0.5≤H1≤10.

[0008] The first direction is perpendicular to the direction of gravity.

[0009] Beneficial effects: By creating a height difference H1 between the two ends of the inner bottom surface along the first direction, the volume of the gap area is reduced, resulting in less electrolyte accumulation at the bottom of the casing and more electrolyte filling other areas of the cavity. This ensures uniform wetting of all parts of the cell and improves battery performance. When the height difference H1 between the two ends of the inner bottom surface along the first direction is too small, the space between the bottom wall of the casing and the cell is large, which can easily lead to a large amount of electrolyte residue, thus affecting the overall wetting effect of the cell. Conversely, when the height difference H1 is too large, the space between the bottom wall of the casing and the cell is too small, lacking sufficient buffer space. When the battery vibrates, the part of the cell's bottom that contacts the higher end of the casing's bottom wall experiences greater stress, which can easily damage the cell.

[0010] Secondly, this utility model also provides a battery pack, comprising:

[0011] As mentioned above, the battery cell;

[0012] And a base plate for supporting the battery cells, with heat exchange channels inside the base plate; the projection of the bottom wall toward the base plate at least partially overlaps with the heat exchange channels;

[0013] Along the first direction, the dimension of the area where the projection of the bottom wall toward the bottom plate coincides with the heat exchange channel is L1, in mm, and the width of the bottom wall along the first direction is L2, in mm, satisfying: 0≤L1 / L2≤1 / 3.

[0014] Beneficial Effects: Due to the inclined design of the bottom wall, when mounting the battery cells to the base plate, the higher end of the inclined bottom wall cannot make good contact with the base plate, resulting in reduced heat exchange efficiency and potential localized poor heat dissipation, affecting battery performance. Since heat transfer is more efficient in the area traversed by the heat exchange channel, limiting the overlap between the bottom wall's projection onto the base plate and the heat exchange channel at least partially enhances the heat exchange effect. By limiting the L1 / L2 ratio, sufficient overlap area between the bottom wall and the heat exchange channel is ensured, improving heat exchange efficiency and preventing localized overheating. When the L1 / L2 ratio is too large, the overlap area between the bottom wall and the heat exchange channel increases, resulting in a significant heat exchange effect, but it can easily lead to insufficient structural strength of the base plate, affecting overall stability. When the ratio is too small, the overlap area decreases, heat exchange efficiency decreases, localized temperature increases, and battery performance deteriorates. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the housing of this utility model;

[0017] Figure 2 This is a cross-sectional schematic diagram of a single battery cell of this utility model;

[0018] Figure 3 This is a cross-sectional schematic diagram of another battery cell of this utility model;

[0019] Figure 4 A cross-sectional view of a battery cell with a support plate;

[0020] Figure 5 This is a cross-sectional schematic diagram of another battery cell according to the present invention;

[0021] Figure 6 This is a top view of the support plate;

[0022] Figure 7 This is a schematic diagram showing the fit between the battery cell and the base plate;

[0023] Figure 8 A diagram showing an explosion-proof valve installed on the bottom wall. Figure 1;

[0024] Figure 9 A diagram showing an explosion-proof valve installed on the bottom wall. Figure 2 .

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Shell; 11. First shell wall; 12. Second shell wall; 13. Bottom wall; 133. Inner bottom surface; 134. Outer bottom surface; 131. First stepped portion; 132. Second stepped portion; 14. Receiving cavity; 15. Bending portion;

[0027] 2. Battery cells;

[0028] 3. Support plate; 31. Through hole;

[0029] 4. Base plate; 41. Support surface; 42. Heat exchange channel;

[0030] 5. Explosion-proof valve. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0035] After the battery is assembled, it needs to be injected with electrolyte. This involves injecting electrolyte into the battery casing to ensure that the cells are fully wetted, thereby ensuring the normal operation of the battery.

[0036] In related technologies, there is often a situation where there is a large amount of residual electrolyte at the bottom of the battery casing. Since the volume of electrolyte injected into the battery is fixed, when too much electrolyte accumulates at the bottom of the casing, the bottom of the cell may receive too much electrolyte, while the top or other areas may not be adequately wetted. This makes it difficult for the electrolyte to evenly cover the entire cell, resulting in some areas not being fully wetted. Uneven wetting hinders the effective transport of lithium ions, thus affecting the overall performance of the cell.

[0037] The following is combined with Figures 1 to 9 The following describes embodiments of the present invention.

[0038] According to an embodiment of the present invention, in one aspect, a battery cell is provided, comprising:

[0039] The shell 1 encloses and forms a receiving cavity 14. The shell 1 includes a bottom wall 13, which is located at the bottom of the shell 1 along the direction of gravity.

[0040] The side surface of the bottom wall 13 facing the receiving cavity 14 is the inner bottom surface 133. There is a height difference H1 between the two ends of the inner bottom surface 133 along the first direction, in mm, which satisfies: 0.5≤H1≤10.

[0041] The first direction is perpendicular to the direction of gravity.

[0042] It should be noted that in this embodiment, the housing 1 is a component used to provide a receiving space to house the electrode assembly and other components and isolate them from the outside environment. The housing 1 generally includes a body with an opening at at least one end and a receiving cavity. The opening of the housing 1 can be closed by a cover plate to seal and isolate the internal environment of the battery cell from the external environment.

[0043] The material of the casing 1 includes, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, aluminum-plastic film, etc.

[0044] The shell 1 can be a quadrangular prism, a cylinder, or other suitable shape.

[0045] The shell 1 can be formed by stamping or welding.

[0046] The housing 1 has an internal cavity 14, which is suitable for placing the battery cell 2 and for containing electrolyte. After the battery cell 2 is placed in the cavity 14, a certain gap is formed between its bottom and the inner bottom surface 133. Electrolyte can easily accumulate in this gap area.

[0047] For battery cells of the same specifications and models, the amount of electrolyte injected into the battery cell is constant, for example, 3ml. Since the electrolyte will naturally flow to the lower end of the cell under the action of gravity, this embodiment reduces the volume of the gap area by making the two ends of the inner bottom surface 133 along the first direction have a height difference H1, which causes less electrolyte to accumulate at the bottom of the shell and more to fill other areas of the receiving cavity 14, ensuring that all parts of the cell are evenly wetted and improving battery performance.

[0048] When the height difference H1 between the two ends of the inner bottom surface 133 along the first direction is too small, the space between the bottom wall 13 of the casing 1 and the cell 2 is large, which can easily lead to a large amount of electrolyte residue, thus affecting the overall wetting effect of the cell. When the height difference H1 is too large, the space between the bottom wall 13 of the casing 1 and the cell 2 is too small, and there is not enough buffer space. When the battery vibrates, the part of the bottom of the cell 2 that contacts the higher end of the bottom wall 13 of the casing 1 is subjected to greater stress, which can easily damage the cell 2.

[0049] This embodiment, by limiting the range of the height difference H1, not only avoids excessive accumulation of electrolyte and improves the uniformity of cell wetting, but also ensures sufficient buffer space to effectively prevent cell damage, thereby optimizing the overall performance of the battery.

[0050] For example, in this embodiment, the value of H1 can be 0.5, 1, 2, 3, 4, 5, 7, 8, or 10, or it can be any range formed by any two of the above values.

[0051] It should be noted that in this embodiment, the direction of gravity specifically refers to the direction of the Earth's gravitational pull, i.e., the vertically downward direction. The first direction is perpendicular to the direction of gravity and can be a horizontal direction or any direction within a plane perpendicular to the direction of gravity.

[0052] In some embodiments, combined with Figure 2 As shown, the housing 1 also includes a first housing wall 11 and a second housing wall 12, which are located at the two ends of the bottom wall 13 along the first direction, and are arranged in parallel; the surface perpendicular to the first housing wall 11 is used as a reference surface.

[0053] The inner bottom surface 133 is inclined relative to the reference surface, and the angle between the inner bottom surface 133 and the reference surface is β, in degrees, satisfying: 1≤β≤10.

[0054] In this embodiment, the surface on which the battery cell is placed in the installation state is defined as the support surface 41. The reference surface can specifically be the support surface 41, that is, the inner bottom surface 133 is inclined relative to the support surface 41. The angle between the inner bottom surface 133 and the support surface 41 is β, in degrees, and satisfies: 1≤β≤10.

[0055] The battery cell can be placed on the base plate or heat exchange plate of the battery pack in the installation state. In this embodiment, the upper surface of the base plate or heat exchange plate is the support surface 41. By setting the inner bottom surface 133 at an angle relative to the support surface 41, the volume of the gap area is reduced, the distribution of electrolyte is further optimized, and less electrolyte accumulates at the bottom of the casing, while more electrolyte fills other areas of the receiving cavity 14, ensuring uniform wetting of all parts of the cell and improving battery performance.

[0056] When the angle β between the inner bottom surface 133 and the supporting surface 41 is too large, the bottom of the cell 2 is too close to the bottom wall 13 of the casing 1, lacking sufficient buffer space. When the battery vibrates or is impacted, the part of the bottom of the cell 2 that contacts the higher end of the bottom wall 13 of the casing 1 experiences greater stress, making the bottom of the cell 2 susceptible to stress concentration and increasing the risk of damage. When the angle β between the inner bottom surface 133 and the supporting surface 41 is too small, the space between the bottom of the cell 2 and the bottom wall 13 of the casing 1 is too large, which can easily lead to a large amount of electrolyte residue and poor cell wetting effect.

[0057] This embodiment controls the range of the angle β between the inner bottom surface 133 and the supporting surface 41, which not only avoids excessive accumulation of electrolyte and improves the uniformity of cell wetting, but also ensures sufficient buffer space to effectively prevent cell damage, thereby optimizing the overall performance of the battery.

[0058] For example, in this embodiment, the value of β can be 1, 2, 3, 4, 5, 7, 8, or 10, or it can be any range formed by any two of the above values.

[0059] In some embodiments, combined with Figure 5 As shown, the surface on which the battery cell is placed in the installation state is defined as the support surface 41, and the side of the bottom wall 13 facing the support surface 41 is defined as the outer bottom surface 134, which is parallel to the support surface 41.

[0060] By making the outer bottom surface 134 parallel to the support surface 41, it is easier to install and fix the battery cells, reduce the installation difficulty caused by angular deviation during assembly, reduce installation errors, improve assembly efficiency, and at the same time ensure that the battery is more stable during transportation and use.

[0061] However, since there is a height difference between the two ends of the inner bottom surface 133 along the first direction, in order to achieve the parallel relationship between the outer bottom surface 134 and the support surface 41, the bottom wall 13 needs to be specially designed. For example, the bottom wall 13 can be locally thickened or the material distribution can be adjusted to compensate for the height difference and ensure the stability of the structure.

[0062] As a variation, in some embodiments, combined with Figure 4 As shown, the outer bottom surface 134 is parallel to the inner bottom surface 133.

[0063] By making the outer bottom surface 134 parallel to the inner bottom surface 133, the processing technology of the bottom wall 13 can be simplified, the manufacturing cost can be reduced, and the functional requirement of the inclined inner bottom surface 133 can be guaranteed. This design makes the shell 1 more consistent in its overall structure, which is conducive to mass production and quality control.

[0064] In some embodiments, the thickness of the bottom wall 13 is D, in mm, which satisfies: 0.8≤D≤2.

[0065] The thickness of the bottom wall 13 is controlled within this range to ensure that the casing 1 has sufficient structural strength to withstand the weight of the battery cell 2 and vibrations and impacts from the external environment, without increasing the overall weight and manufacturing cost due to excessive thickness. At the same time, a reasonable thickness also helps to improve the thermal management performance of the battery, ensuring its stable operation under complex working conditions.

[0066] In some embodiments, the bottom wall 13 is non-planar.

[0067] The bottom wall 13 has a non-planar structure, such as a wave-shaped, arc-shaped, or stepped shape. This non-planar design reduces the volume of the gap area, causing less electrolyte to accumulate at the bottom of the casing and more to fill other areas of the receiving cavity 14, ensuring uniform wetting of all parts of the cell and improving battery performance.

[0068] In some embodiments, the bottom wall 13 includes a first step portion 131 and a second step portion 132, which are staggered.

[0069] In this embodiment, the bottom wall 13 adopts a stepped form, combined with Figure 3 As shown, the first step 131 is located at a lower position on the bottom wall 13, and the second step 132 is located at a higher position, forming a staggered structure. On the one hand, this allows the inner bottom surface 133 to form a height difference, thereby optimizing the electrolyte distribution, reducing bottom accumulation, improving the uniformity of cell wetting, and enhancing the overall performance and stability of the battery. On the other hand, it allows at least a portion of the bottom wall 13 to maintain a parallel relationship between the outer bottom surface 134 and the support surface 41, further improving the structural stability and ease of installation of the battery cell.

[0070] Additionally, the staggered design effectively increases the structural strength of the bottom wall 13, improving the casing's ability to protect the battery cells. Furthermore, the staggered design increases the space between the battery's outer bottom surface 134 and the casing's bottom plate, thereby enhancing the cushioning effect.

[0071] In addition, the staggered structure facilitates heat conduction, optimizes heat dissipation, and extends battery life.

[0072] The bottom wall 13 adopts a stepped form, which can be achieved through injection molding or die casting when the shell 1 is integrally formed, which is convenient for processing and reduces production costs.

[0073] In some embodiments, combined with Figure 2 As shown, the battery cell also includes:

[0074] Battery cell 2 is disposed within the receiving cavity 14;

[0075] The height of cell 2 is H2, in mm, and satisfies: 0.005≤H1 / H2≤0.15.

[0076] Cell 2 can be formed by winding or stacking.

[0077] When the cell 2 is taller, the electrolyte wetting becomes more difficult. Therefore, the height difference H1 between the two ends of the inner bottom surface 133 along the first direction needs to be increased to reduce the amount of residual electrolyte at the bottom, thereby allowing more electrolyte to enter the cell 2 and improving the wetting effect. Conversely, when the cell 2 is shorter, the electrolyte wetting becomes less difficult, and the height difference H1 can be reduced accordingly to ensure uniform electrolyte distribution and improve cell performance.

[0078] Furthermore, when the H1 / H2 ratio is too large, the area where the bottom of cell 2 contacts the higher end of the bottom wall 13 of the casing 1 experiences greater stress, which can easily damage cell 2. When the H1 / H2 ratio is too small, it can easily lead to a large amount of electrolyte residue, thereby affecting the overall wetting effect of the cell.

[0079] This embodiment optimizes electrolyte utilization by precisely controlling the H1 / H2 ratio, which not only avoids excessive electrolyte accumulation and improves the uniformity of cell wetting, but also ensures sufficient buffer space to effectively prevent cell damage, thereby optimizing the overall performance of the battery.

[0080] In this embodiment, the height of cell 2 is H2 in mm, which satisfies: 60≤H2≤240.

[0081] For example, in this embodiment, the value of H1 / H2 can be 0.005, 0.01, 0.03, 0.05, 0.1, 0.12, 0.13, 0.14, or 0.15, or it can be any range formed by any two of the above values.

[0082] In some embodiments, the battery cell further includes:

[0083] Battery cell 2 is disposed within the receiving cavity 14;

[0084] Support plate 3 is disposed between battery cell 2 and bottom wall 13, and is suitable for supporting battery cell 2.

[0085] Combination Figure 4 As shown, the housing 1 also includes a first housing wall 11 and a second housing wall 12, which are located at opposite ends of the bottom wall 13 along a first direction. A bend 15 is formed at the connection between the first housing wall 11 and the bottom wall 13. Similarly, a bend 15 is also formed at the connection between the second housing wall 12 and the bottom wall 13. Specifically, the bend 15 can be arc-shaped, thereby gradually narrowing the distance between the first housing wall 11 and the second housing wall 12 along the first direction. The support plate 3 can be supported on the bend 15, thus ensuring that the support plate 3 can support the battery cell 2 after it is placed in the receiving cavity 14.

[0086] The support plate 3 can maintain an appropriate gap between the battery cell 2 and the bottom wall 13, avoid direct contact, reduce friction and wear, and extend the service life of the battery cell.

[0087] Meanwhile, the support plate 3 can form insulation between the battery cell 2 and the bottom wall 13 to prevent short circuits.

[0088] The support plate 3 can keep the cell 2 stable within the housing cavity 14, preventing displacement caused by vibration or impact, and further ensuring the structural safety and electrical performance stability of the battery cell.

[0089] The support plate can be made of at least one of polytetrafluoroethylene, metal, carbon fiber, mica, and ceramic.

[0090] In some embodiments, the support plate 3 has a through hole 31, and the surface area of ​​the larger surface of the support plate 3 is S2, in mm. 2 The area of ​​the through hole 31 perpendicular to the large surface of the support plate 3 is S1, in mm. 2 The following condition must be met: 0.005 ≤ S1 / (H1·S2) ≤ 0.5, in mm. -1 .

[0091] The support plate 3 has through holes 31 to facilitate electrolyte flow and enhance wetting effect. The design of the through holes 31 must ensure uniform electrolyte distribution, avoid local accumulation, and further improve cell performance.

[0092] When the height difference H1 between the two ends of the inner bottom surface 133 along the first direction is greater, the stress on the part where the support plate 3 contacts the higher end of the bottom wall 13 is greater. Therefore, it is necessary to increase the hole area of ​​the through hole 31 to improve the energy absorption and buffering effect. Conversely, when H1 is smaller, the stress on the part where the support plate 3 contacts the higher end of the bottom wall 13 is smaller, and the hole area of ​​the through hole 31 can be reduced accordingly to optimize the overall structural strength and electrolyte distribution uniformity.

[0093] If the value of S1 / (H1·S2) is too large, the area of ​​the through hole 31 will be larger, and the electrolyte will flow more easily from the through hole 31 into the lower part of the support plate 3; if the value of S1 / (H1·S2) is too small, the area of ​​the through hole 31 will be smaller, the energy absorption effect will be worse, and the stress on the part of the support plate 3 in contact with the higher end of the bottom wall 13 will be too large, resulting in poor buffering effect.

[0094] Additionally, in this embodiment, the surface area S2 of the large surface of the support plate 3 accounts for 40% to 95% of the area of ​​the bottom wall 13.

[0095] For example, in this embodiment, the value of S1 / (H1·S2) can be 0.005 or 0.01 or 0.03 or 0.05 or 0.1 or 0.15 or 0.18 or 0.2 or 0.25 or 0.3 or 0.45 or 0.47 or 0.5, or it can be any range formed by any two of the above values.

[0096] In some embodiments, the following condition is satisfied: 0.05≤S1 / S2≤0.3.

[0097] Because the bottom wall 13 of the shell 1 is inclined, the part where the support plate 3 contacts the higher end of the bottom wall 13 experiences the greatest stress. In order to avoid excessive stress concentration in this part, the hole area of ​​the through hole 31 of the support plate 3 can be increased to play a better buffering role. By increasing the hole area of ​​the through hole 31 of the support plate 3, stress can be effectively dispersed and local stress concentration can be prevented, thereby improving the durability and reliability of the overall structure.

[0098] When the S1 / S2 ratio increases, the area of ​​the via 31 increases accordingly, which facilitates smoother electrolyte flow. However, when the ratio is too large, the area of ​​the via 31 becomes too large, making it easier for the electrolyte to flow into the lower part of the plate from the opening, which can lead to uneven electrolyte distribution and affect cell performance. Conversely, when the S1 / S2 ratio decreases, the area of ​​the via 31 decreases accordingly, which helps improve the structural strength of the support plate 3. However, when the ratio is too small, the area of ​​the via 31 becomes too small, hindering electrolyte flow, weakening the wetting effect, and resulting in poor buffering effect of the support plate 3, which can easily lead to localized stress concentration.

[0099] Additionally, in this embodiment, the surface area S2 of the large surface of the support plate 3 ranges from 1000 to 32000 mm. 2The area S1 of the through hole 31, which is perpendicular to the large surface of the support plate 3, ranges from 50 to 9000 mm. 2 .

[0100] In some embodiments, the minimum distance between the through hole 31 and the edge of the support plate 3, parallel to the plane containing the support plate 3, is greater than or equal to 3 mm. By limiting the minimum distance between the through hole 31 and the edge of the support plate 3, it is possible to effectively prevent the through hole 31 from being too close to the edge, which would reduce the structural strength and thus improve the overall structural stability of the support plate 3, making it less prone to breakage or deformation under external forces. Additionally, the through hole 31 should not be too far from the edge of the support plate 3 to avoid a decrease in the buffering effect.

[0101] In some embodiments, the battery cell further includes a terminal post, and the surface of the housing 1 used to set the terminal post is the terminal post surface; the terminal post surface and the bottom wall 13 are opposite surfaces, and the terminal post surface and the bottom wall 13 are the same surface.

[0102] According to an embodiment of the present invention, another aspect provides a battery pack, comprising:

[0103] As mentioned above, the battery cell;

[0104] And a base plate 4 for supporting the battery cell, with a heat exchange channel 42 inside the base plate 4; the projection of the bottom wall 13 of the shell 1 toward the base plate 4 at least partially overlaps with the heat exchange channel 42.

[0105] Combination Figure 7 As shown, along the first direction, the dimension of the area where the projection of the bottom wall 13 toward the bottom plate 4 coincides with the heat exchange channel 42 is L1, in mm, and the width of the bottom wall 13 along the first direction is L2, in mm, satisfying: 0≤L1 / L2≤1 / 3.

[0106] A battery pack may include a battery housing, which is suitable for placing individual battery cells. These individual battery cells can be stacked to form a battery pack for easy assembly.

[0107] The battery pack also includes a base plate 4 for supporting the individual battery cells, which can be a heat exchange plate.

[0108] In this embodiment, a heat exchange channel 42 is provided inside the base plate 4 to enhance the heat exchange effect, ensure that the temperature of the battery cells is uniform during operation, and extend the service life.

[0109] In this embodiment, the bottom wall 13 is designed with an inclination. When the battery cell is installed on the base plate 4, the higher end of the inclination bottom wall 13 cannot make good contact with the base plate 4, which leads to a decrease in heat exchange effect and easy to cause poor local heat dissipation, affecting battery performance.

[0110] Heat transfer is more efficient in the area through which the heat exchange channel 42 flows, and the heat exchange effect is enhanced by limiting the projection of the bottom wall 13 toward the bottom plate 4 to at least partially overlap with the heat exchange channel 42.

[0111] By limiting the L1 / L2 ratio, sufficient overlap area between the bottom wall 13 and the heat exchange channel 42 is ensured, improving heat exchange efficiency and avoiding local overheating. When the L1 / L2 ratio is too large, the overlap area between the bottom wall 13 and the heat exchange channel 42 increases, resulting in a significant heat exchange effect, but it can easily lead to insufficient structural strength of the bottom plate 4, affecting overall stability. When the ratio is too small, the overlap area decreases, heat exchange efficiency decreases, local temperature rises, and battery performance can easily deteriorate.

[0112] This embodiment ensures efficient heat exchange and maintains the structural strength of the base plate 4 by reasonably controlling the L1 / L2 ratio, thus ensuring the overall performance stability of the battery pack.

[0113] In this embodiment, the value of L2 can be in the range of 20-90 mm.

[0114] In some embodiments, the base plate 4 and the bottom wall 13 are bonded together by a heat-conducting component.

[0115] Since the higher end of the inclined bottom wall 13 cannot make good contact with the bottom plate 4, the heat exchange effect is reduced. By using a thermally conductive adhesive to bond the bottom plate 4 and the bottom wall 13, the contact gap is effectively filled, the thermal conductivity is improved, the heat is evenly transferred, local overheating is avoided, and the overall heat dissipation effect of the battery pack is further optimized.

[0116] In this embodiment, the thermally conductive component uses a thermally conductive structural adhesive. The material of the structural adhesive can be one of the following: (1) The structural adhesive is an insulating material doped with a conductive medium. The structural adhesive can use an insulating material as the base material, that is, a non-conductive adhesive, such as epoxy resin, silicone rubber, polyurethane, etc. (2) The structural adhesive can also be epoxy resin structural adhesive and polyurethane structural adhesive. (3) The structural adhesive is a two-component epoxy resin structural adhesive, a two-component acrylic structural adhesive, a two-component polyurethane structural adhesive, or a two-component silane structural adhesive.

[0117] In some embodiments, combined with Figure 8 As shown, an explosion-proof valve 5 is provided on the bottom wall 13 of the housing 1. In a direction parallel to the bottom wall 13 and in the same plane as the first direction, the width of the explosion-proof valve 5 is M, in mm, and satisfies: 8≤M≤50.

[0118] Furthermore, the lifting angle of the explosion-proof valve 5 relative to the base plate 4 is within 10°.

[0119] It should be noted that an explosion-proof valve refers to a component or part that can be actuated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold.

[0120] During battery use, explosion-proof valves are mainly used to prevent excessive pressure buildup inside the battery, which could cause deformation or explosion, by allowing gas to escape and reducing the internal pressure of the battery in the event of thermal runaway or other situations.

[0121] The explosion-proof valve 5 is installed on the bottom wall 13 to ensure that the pressure can be released quickly when the battery cell experiences thermal runaway, so as to facilitate the rapid discharge of gas and prevent the internal pressure of the battery pack from becoming too high.

[0122] Because the bottom wall 13 is designed with an incline, the explosion-proof valve 5 is positioned behind it, creating a height difference between its two ends. By reasonably controlling the lower limit of the width M of the explosion-proof valve 5, the exhaust space between the explosion-proof valve and the bottom plate of the enclosure can be increased, which is beneficial for exhaust during thermal runaway. This ensures smooth gas flow during pressure relief by the explosion-proof valve 5, avoiding poor pressure relief due to insufficient height difference and improving the safety performance of the battery pack. At the same time, by controlling the upper limit of the width M of the explosion-proof valve 5, the structural strength of the explosion-proof valve is prevented from being insufficient due to excessive width, thus avoiding deformation or damage under external forces in non-thermal runaway conditions, which would affect its normal function.

[0123] The explosion-proof valve 5 has a lifting angle of less than 10° relative to the base plate 4. This prevents the explosion-proof valve from obstructing gas discharge and affecting its pressure relief efficiency during thermal runaway pressure relief due to an excessively steep angle. By controlling the lifting angle to within 10°, it ensures that gas can be discharged quickly and smoothly when the explosion-proof valve opens, reducing the risk of internal pressure accumulation and thus improving the safety performance of the battery pack under extreme conditions. Simultaneously, this angle design also avoids structural stress concentration caused by an excessively large angle in the explosion-proof valve.

[0124] For example, in this embodiment, the value of M can be 8, 10, 15, 18, 20, 25, 29, 34, 42, or 50, or it can be any range formed by any two of the above values.

[0125] In some embodiments, combined with Figure 9 As shown, in the plane perpendicular to the bottom wall 13, the central axis of the bottom wall 13 is Q1, and the central axis of the explosion-proof valve 5 is Q2. Q2 is located on the lower side of Q1, near the bottom wall 13.

[0126] The distance between Q2 and Q1 is C, in mm, and satisfies: 0.1≤C≤10.

[0127] By positioning Q2 on the lower side of Q1 near the bottom wall 13, the explosion-proof valve 5 is brought closer to the area with a larger gas storage capacity inside the battery cell. This facilitates rapid pressure relief in case of thermal runaway, reduces gas flow resistance, improves pressure relief efficiency, ensures a rapid decrease in internal pressure of the battery pack, and effectively prevents the risk of explosion.

[0128] The value of C needs to be determined by comprehensively considering the internal space of the battery cell, the internal structure of the battery pack, and the gas flow characteristics. This ensures that the explosion-proof valve 5 can efficiently relieve pressure under extreme conditions, avoiding pressure relief delays or failures due to improper spacing. When the value of C is too large, although the explosion-proof valve 5 is closer to the area with a large gas volume inside the battery cell, reducing gas flow resistance, it may result in insufficient venting space between the explosion-proof valve and the bottom plate of the enclosure, affecting the pressure relief effect. Conversely, when the value of C is too small, the explosion-proof valve 5 is farther away from the area with a large gas volume inside the battery cell, increasing gas flow resistance and reducing pressure relief efficiency.

[0129] Therefore, by setting the C value appropriately and balancing the relationship between the inner and outer sides of the bottom wall 13, the explosion-proof valve 5 can still effectively release pressure under extreme conditions, thereby improving the overall safety performance of the battery pack.

[0130] For example, in this embodiment, the value of C can be 0.1 or 0.5 or 1.5 or 2.3 or 3.6 or 4.7 or 5.2 or 6.4 or 7 or 8 or 9.2 or 10, or it can be any range formed by any two of the above values.

[0131] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A battery cell, characterized in that, include: A shell (1) encloses and forms a receiving cavity (14), the shell (1) including a bottom wall (13) located at the bottom of the shell (1) along the direction of gravity; The side surface of the bottom wall (13) facing the receiving cavity (14) is the inner bottom surface (133). The inner bottom surface (133) has a height difference H1 at both ends along the first direction, in mm, which satisfies: 0.5≤H1≤10. Wherein, the first direction is perpendicular to the direction of gravity.

2. The battery cell according to claim 1, characterized in that, The shell (1) further includes a first shell wall (11) and a second shell wall (12), the first shell wall (11) and the second shell wall (12) are respectively located at both ends of the bottom wall (13) along the first direction, and the first shell wall (11) and the second shell wall (12) are arranged in parallel; the surface perpendicular to the first shell wall (11) is used as a reference surface; The inner bottom surface (133) is inclined relative to the reference surface, and the angle between the inner bottom surface (133) and the reference surface is β, in degrees, satisfying: 1≤β≤10.

3. The battery cell according to claim 1, characterized in that, The surface on which the battery cell is placed in the installed state is defined as the support surface (41), and the side surface of the bottom wall (13) facing the support surface (41) is defined as the outer bottom surface (134), which is parallel to the support surface (41).

4. The battery cell according to claim 3, characterized in that, The outer bottom surface (134) is parallel to the inner bottom surface (133).

5. The battery cell according to claim 4, characterized in that, The thickness of the bottom wall (13) is D, in mm, and satisfies: 0.8≤D≤2.

6. The battery cell according to claim 1, characterized in that, The bottom wall (13) is non-planar.

7. The battery cell according to claim 6, characterized in that, The bottom wall (13) includes a first stepped section (131) and a second stepped section (132), which are staggered.

8. The battery cell according to claim 1, characterized in that, The battery cell also includes: The battery cell (2) is disposed within the receiving cavity (14); The height of the battery cell (2) is H2, in mm, and satisfies: 0.005≤H1 / H2≤0.

15.

9. The battery cell according to claim 1, characterized in that, The battery cell also includes: The battery cell (2) is disposed within the receiving cavity (14); A support plate (3) is disposed between the battery cell (2) and the bottom wall (13), and the support plate (3) is adapted to support the battery cell (2).

10. The battery cell according to claim 9, characterized in that, The support plate (3) has through holes (31), and the surface area of ​​the large surface of the support plate (3) is S2, in mm. 2 The area of ​​the through hole (31) perpendicular to the large surface of the support plate (3) is S1, in mm. 2 The following condition must be met: 0.005 ≤ S1 / (H1·S2) ≤ 0.5, in mm. -1 .

11. The battery cell according to claim 10, characterized in that, It satisfies: 0.05≤S1 / S2≤0.

3.

12. The battery cell according to claim 10, characterized in that, In a plane parallel to the support plate (3), the minimum distance between the through hole (31) and the edge of the support plate (3) is greater than or equal to 3 mm.

13. The battery cell according to claim 2, characterized in that, The battery cell also includes a terminal post, and the surface of the housing (1) for setting the terminal post is the terminal post surface; the terminal post surface and the bottom wall (13) are opposite surfaces, and the terminal post surface and the bottom wall (13) are the same surface.

14. A battery pack, characterized in that, include: The battery cell as described in any one of claims 1 to 13 above; And a base plate (4) for supporting the battery cell, wherein a heat exchange channel (42) is provided inside the base plate (4); the projection of the bottom wall (13) of the shell (1) toward the base plate (4) at least partially overlaps with the heat exchange channel (42); Along the first direction, the size of the area where the projection of the bottom wall (13) toward the bottom plate (4) coincides with the area of ​​the heat exchange channel (42) is L1, in mm, and the width of the bottom wall (13) along the first direction is L2, in mm, satisfying: 0≤L1 / L2≤1 / 3.

15. The battery pack according to claim 14, characterized in that, The base plate (4) and the bottom wall (13) are bonded together by a heat-conducting component.

16. The battery pack according to claim 14, characterized in that, An explosion-proof valve (5) is provided on the bottom wall (13) of the housing (1). In a direction parallel to the bottom wall (13) and in the same plane as the first direction, the width of the explosion-proof valve (5) is M, in mm, and satisfies: 8≤M≤50. Furthermore, the lifting angle of the explosion-proof valve (5) relative to the base plate (4) is within 10°.

17. The battery pack according to claim 16, characterized in that, In a plane perpendicular to the bottom wall (13), the central axis of the bottom wall (13) is Q1, the central axis of the explosion-proof valve (5) is Q2, and Q2 is located on the lower side of Q1 near the bottom wall (13). The distance between Q2 and Q1 is C, in mm, and satisfies: 0.1≤C≤10.

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