cell

Abstract

The application relates to the technical field of batteries, and discloses a battery cell, which comprises a shell, a first pole group and a second pole group, the first pole group and the second pole group are arranged in the shell, the first pole group and the second pole group are arranged in sequence along a Y direction, the first pole group comprises a plurality of first positive pole pieces and a plurality of first negative pole pieces which are stacked along a Z direction, the second pole group comprises a plurality of second positive pole pieces and a plurality of second negative pole pieces which are stacked along the Z direction, the plurality of first positive pole pieces jointly form a first positive pole end face towards one end of the second pole group along the Y direction, and the plurality of first negative pole pieces jointly form a first negative pole end face towards one end of the second pole group along the Y direction; the plurality of second positive pole pieces jointly form a second positive pole end face towards one end of the first pole group along the Y direction, and the plurality of first negative pole pieces jointly form a second negative pole end face towards one end of the first pole group along the Y direction; wherein the first positive pole end face and the second positive pole end face are electrically connected through a conductive coating, and the first negative pole end face and the second negative pole end face are electrically connected through the conductive coating.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a battery cell. Background Technology

[0002] With the continuous maturation of lithium-ion battery technology, lithium-ion batteries have been widely used as power batteries in electric vehicles and energy storage, and the requirements for their performance and safety are constantly increasing. As the most critical safety unit and core component in the battery pack, the structural design of the lithium cell directly affects the overall safety and reliability of the battery.

[0003] Therefore, higher requirements are placed on the energy density and safety performance of batteries. Summary of the Invention

[0004] This invention provides a battery cell to solve the above-mentioned technical problems.

[0005] This invention provides a battery cell, including a casing, a first electrode group, and a second electrode group. The first electrode group and the second electrode group are disposed inside the casing and arranged sequentially along the Y direction. The first electrode group includes a plurality of first positive electrode plates and a plurality of first negative electrode plates stacked along the Z direction. The plurality of first positive electrode plates together form a first positive terminal face along the Y direction towards one end of the second electrode group, and the plurality of first negative electrode plates together form a first negative terminal face along the Y direction towards one end of the second electrode group. The second electrode group includes a plurality of second positive electrode plates and a plurality of second negative electrode plates stacked along the Z direction. The plurality of second positive electrode plates together form a second positive terminal face along the Y direction towards one end of the first electrode group, and the plurality of first negative electrode plates together form a second negative terminal face along the Y direction towards one end of the first electrode group. The first positive terminal face and the second positive terminal face, as well as the first negative terminal face and the second negative terminal face, are electrically connected by a conductive coating.

[0006] Beneficial effects: Therefore, this invention arranges the first and second electrode groups sequentially along the length of the cell, and forms positive and negative end faces at the ends of each electrode group for electrical connection with other electrode groups. Electrical connection is ultimately achieved through a conductive coating, improving the space utilization of the electrode groups within the casing and thus increasing the cell capacity.

[0007] Optionally, along the Y direction, a first protrusion and a second protrusion are formed at one end of the first pole group facing the second pole group. The end face of the first protrusion along the Y direction is the first positive end face, and the end face of the second protrusion along the Y direction is the first negative end face. The first protrusion and the second protrusion are spaced apart along the X direction, and the space between them forms a first clearance groove. The first clearance groove penetrates the first pole group along the Z direction.

[0008] Beneficial effects: Based on this, the present invention forms a local gap region between the first electrode group and the second electrode group. On the one hand, it provides a storage space for electrolyte, which is conducive to the collection and replenishment of electrolyte in the end region of the electrode group. On the other hand, it can improve the penetration and wetting conditions of electrolyte into the electrode group, thereby improving the overall wetting consistency of the electrode sheet, reducing the risk of increased polarization or performance degradation caused by insufficient wetting, and thus helping to improve the electrochemical performance stability and reliability of the battery cell.

[0009] Optionally, along the Y direction, a third protrusion and a fourth protrusion are formed at the end of the second pole group facing the first pole group. The end face of the third protrusion along the Y direction is the second positive end face, and the end face of the fourth protrusion along the Y direction is the second negative end face. The third protrusion and the fourth protrusion are spaced apart along the X direction, and the space between them forms a second clearance groove. The second clearance groove penetrates the second pole group along the Z direction, and the second clearance groove and the first clearance groove are arranged opposite to each other along the Y direction.

[0010] Beneficial effects: Based on this, in this invention, the end faces of the first and third protrusions, and the end faces of the second and fourth protrusions, are electrically connected through conductive coatings, thereby forming a stable and reliable electrical connection between the first and second electrode groups. Simultaneously, by providing the second cavitation channel in the second electrode group, the local gap between the first and second electrode groups can be further expanded, thus forming a larger liquid storage space at the electrode group ends. This facilitates the collection, flow, and replenishment of the electrolyte, further improving the overall wetting effect of the electrode group. Furthermore, the second cavitation channel and the first cavitation channel are arranged opposite each other along the Y-direction. The openings of the first and second cavitation channels along the Y-direction are aligned and connected, forming a connected liquid storage channel, thereby further improving the consistency, safety, and cycle stability of the battery cell.

[0011] Optionally, along the X direction, a first protrusion is formed on both sides of the first electrode group, and a second protrusion is formed on both sides of the second electrode group. Along the Y direction, the first protrusion and the second protrusion are spaced apart, and the space between the first protrusion and the second protrusion located on the same side along the X direction forms a liquid storage space. Wherein, along the Y direction, the distance from the first protrusion to the end face of the first pole group facing the second pole group and the distance from the second protrusion to the end face of the second pole group facing the first pole group are both W1; Where 18mm≤W1≤60mm.

[0012] Beneficial effects: Based on this, the present invention forms liquid storage spaces on both sides of the first and second electrode groups along the X direction, so that the electrolyte can be fully collected and replenished on the side of the electrode groups, thereby further improving the overall wetting effect of the electrode groups and enhancing the consistency and stability of the electrochemical reaction.

[0013] Furthermore, when W1 is less than 18mm, the liquid storage space formed laterally by a single electrode group may be insufficient, and the electrolyte's ability to collect in this area is limited, making it difficult to significantly improve the electrode group's wetting effect. When W1 is greater than 60mm, although a larger liquid storage space can be obtained, it will inevitably compress the volume of the electrode group corresponding to the first and second protrusions, resulting in a limited increase in the effective volume of the electrode group, which is not conducive to further improving the cell capacity.

[0014] Optionally, along the X direction, the distance between the first protrusions on both sides of the first pole group is A, and the length of the two sides of the first pole is F, satisfying 6mm≤AF≤12mm.

[0015] Beneficial effects: When AF is less than 6mm, the depth of the electrolyte storage space formed by a single electrode group along the X direction is insufficient, and the improvement of electrolyte wetting effect is limited; when AF is greater than 12mm, the effective volume of the electrode group along the X direction is greatly reduced, significantly reducing the electrode group capacity and affecting the energy density of the cell.

[0016] Optionally, an explosion-proof valve is provided on the outer casing, and the explosion-proof valve is correspondingly provided with the liquid storage space along the X direction, and the explosion-proof valve is connected to the liquid storage space.

[0017] Beneficial effects: In this invention, the gas can be discharged from the outer casing through the liquid storage space and the explosion-proof valve, thereby avoiding the direct action of high-temperature and high-pressure gas on the electrode group area.

[0018] Optionally, the housing includes a shell, and the two opposing first shell walls along the X direction are each formed with a third groove and a fourth groove for accommodating the first boss and the second boss. The bottom of the third groove and the fourth groove protrudes outward relative to the shell along the X direction, and the explosion-proof valve is located between the third groove and the fourth groove.

[0019] Beneficial effects: Based on this, the present invention sets the explosion-proof valve between the third and fourth grooves, thereby forming a force-bearing support structure on both sides of the explosion-proof valve. This helps to reduce the risk of damage to the explosion-proof valve under external force while improving the structural strength of the outer shell sidewall.

[0020] Optionally, along the Y direction, the end faces of the first pole group and the second pole group that are opposite to each other are provided with a fifth protrusion and a sixth protrusion, and along the X direction, the fifth protrusion and the sixth protrusion are spaced apart. The outer shell includes a shell and cover plates located at both ends of the shell along the Y direction. The cover plates include a fifth groove and a sixth groove for accommodating the fifth protrusion and the sixth protrusion, respectively.

[0021] Along the Z direction, the distance between the two sides of the fifth boss is K, and the distance between the two sides of the first pole group is B2, satisfying 0.35≤K / B2≤0.7.

[0022] Beneficial effects: Based on this, the present invention further increases the volume of the first and second electrode groups by using the fifth and sixth protrusions, thereby obtaining a cell with higher capacitance. Simultaneously, the cover plate is adapted to the electrode groups.

[0023] Furthermore, when K / B2 is less than 0.35, the proportion of the fifth boss on the end face of the first pole group is too small, resulting in insufficient thickness of the fifth boss and limited capacity improvement; when K / B2 is greater than 0.7, the proportion of the fifth boss thickness is too large, which will significantly increase the difficulty of stamping the cover plate and lead to increased manufacturing costs.

[0024] Optionally, along the Y direction, the end face of the first electrode group away from the second electrode group includes a plane and inclined planes located on both sides of the plane along the X direction, and the ends of the two inclined planes away from the plane are configured to be far apart from each other along the X direction; along the Y direction, the end face of the first electrode group away from the second electrode group is provided with a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate; along the Z direction, the positive electrode tab and the negative electrode tab are located on both sides of the fifth boss and the sixth boss, respectively, and the two ends of the positive electrode tab and / or the negative electrode tab extend to the two inclined planes along the X direction, respectively.

[0025] Beneficial effects: Based on the structure of the end of the first electrode group, the present invention can set the positive electrode tab and / or negative electrode tab to extend to the two inclined surfaces at both ends along the X direction, thereby effectively increasing the length of the electrode tab, which is beneficial to current dispersion and heat release, and avoids excessive local temperature rise of the electrode tab under fast charging conditions.

[0026] Optionally, along the X direction, the plane length is L3, and the distance between the two opposite sides of the fifth and sixth protrusions is L2, satisfying 0mm≤L3-L2≤16mm.

[0027] Beneficial effects: When L3-L2 is too small, the fifth and sixth protrusions are not sufficiently limiting in the X direction, which is not conducive to the stable installation of the pole group; when L3-L2 is too large, it will cause the proportion of the protrusion size at the end of the pole group to be too high, affecting the volume utilization rate of the pole group.

[0028] Optionally, the angle between the two inclined planes is N, which satisfies 50°≤N≤110°.

[0029] Beneficial effects: When N is less than 50°, the angle between the two inclined planes is too small, which will limit the effective length of the tabs extending along the inclined planes, which is not conducive to current dispersion and heat dissipation, and is prone to local overheating under fast charging or high current conditions.

[0030] When N is greater than 110°, the included angle between the two inclined planes is too large, and the end of the first pole group tends to be a flat structure. This weakens the guiding and supporting effect of the inclined plane on the pole lugs, which is not conducive to the pole lugs unfolding along the inclined planes and increasing their effective length. It may affect the assembly matching between the cover plate and the pole group.

[0031] Optionally, along the Z direction, both surfaces of the first electrode group are provided with a third protrusion, and along the Y direction, the end face of the third protrusion facing away from the second electrode group is coplanar with the end face of the first electrode group facing away from the second electrode group; the surfaces of the second electrode group along the Z direction are provided with a fourth protrusion, and along the Y direction, the end face of the fourth protrusion facing away from the first electrode group is coplanar with the end face of the second electrode group facing away from the first electrode group. The outer casing includes a housing, and along the Z direction, a first groove for accommodating a third boss and a second groove for accommodating a fourth boss are formed on two opposing second shell walls of the housing. Along the Z direction, the outer surface of the second shell wall away from the first pole group has a first protrusion corresponding to the first groove and a second protrusion corresponding to the second groove. Along the Y direction, the third protrusion and the fourth protrusion are spaced apart, the first protrusion and the second protrusion are spaced apart and form a space. The shell includes a cooling plate, which is disposed in the space. The cooling plate has a medium channel inside. Along the Y direction, the distance between the third protrusion and the end face of the first pole group facing the second pole group is W2, and the length of the first pole group along the Y direction is E, satisfying 250mm≤E≤600mm, 0.15≤W2 / E≤0.33; Along the X direction, the distance between the two sides of the third boss is L1, and the distance between the two sides of the first pole group is A, satisfying 0.33≤L1 / A≤0.7; Along the Z direction, the distance between the third protrusions on both sides of the first pole group is B1, and the distance between the two surfaces of the first pole group along the Z direction is B2, satisfying 20mm≤B1-B2≤60mm.

[0032] Beneficial effects: This invention achieves effective cooling of the electrode group by setting a cooling plate between the third and fourth protrusions and introducing a cooling medium into the medium channel within the cooling plate. Simultaneously, since this cooling area corresponds to the electrical connection point between the first and second electrode groups, where resistance is high and heat generation is concentrated, direct heat exchange with the cooling medium helps suppress local temperature rise and improves cell safety.

[0033] Furthermore, when W2 / E is less than 0.15, the length of the third protrusion is insufficient, which limits the size of the corresponding cooling structure and results in poor cell cooling. When W2 / E is greater than 0.33, the length of the third protrusion is too large, which will limit the increase in the size of its protrusion and affect the increase in the size of the electrode assembly.

[0034] Furthermore, when L1 / A is less than 0.33, the proportion of the third protrusion's dimension in the X-direction relative to the overall width of the first electrode group is insufficient. This limits the increase in the volume of the third protrusion, making it difficult to effectively increase the electrode group volume while simultaneously achieving structural reinforcement, heat dissipation, and limiting functions. Consequently, its effect on improving cell capacity and structural stability is limited. When L1 / A is greater than 0.7, the third protrusion's proportion in the first electrode group is too large. Correspondingly, the size of the first groove on the outer casing that matches it must also be increased. This not only significantly increases the difficulty of stamping or forming the aluminum casing and cover plate but also increases material usage and processing complexity, leading to increased manufacturing costs and adversely affecting product consistency and yield.

[0035] Furthermore, when B1-B2 is less than 20mm, the protrusion height of the third boss in the Z direction is insufficient, making it difficult to significantly increase the effective volume of the electrode assembly. Simultaneously, the limiting and supporting effect formed between the third boss and the corresponding first groove in the housing is weak, which is detrimental to the stable fixation of the electrode assembly within the housing. When B1-B2 is greater than 60mm, the protrusion height of the third boss in the Z direction is excessive, significantly increasing the structural dimensional requirements of the electrode assembly and housing in this direction. This leads to increased difficulty in forming the housing sidewalls and corresponding grooves, resulting in higher material usage and manufacturing costs. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the electrode assembly structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the first pole group structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the second pole group structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the electrode assembly dimensions according to an embodiment of the present invention; Figure 6 for Figure 5The right-side side view; Figure 7 This is a schematic diagram of the shell structure according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the cover plate structure according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the back structure of the cover plate according to an embodiment of the present invention; Figure 10 for Figure 2 A magnified view of a local area A in the middle; Figure 11 for Figure 7 A magnified view of a local area B in the middle.

[0038] Explanation of reference numerals in the attached figures: 1. Outer shell; 101. Explosion-proof valve; 102. Shell; 103. First groove; 1031. First protrusion; 1032. First ladder; 104. Second groove; 1041. Second protrusion; 105. Cooling plate; 106. Cover plate; 1061. Fifth groove; 1062. Sixth groove; 107. Third groove; 108. Fourth groove; 2. First pole group; 201. First clearance groove; 202. First boss; 203. First protrusion; 204. Second protrusion; 205. Third protrusion; 206. First positive end face; 207. First negative end face; 3. Second pole group; 301. Third protrusion; 302. Fourth protrusion; 303. Second clearance groove; 304. Second protrusion; 305. Fourth protrusion; 306. Second positive end face; 307. Second negative end face; 4. Inclined surface; 5. Conductive coating; 6. Liquid storage space; 7. Fifth protrusion; 8. Sixth protrusion; 9. Electrode tab; 901. Straight section; 902. Inclined section; 10. Plane. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the development of battery technology, in order to improve battery capacity, current batteries are developing towards longer electrode packs. When the electrode packs are made longer, on the one hand, the difficulty of inserting the electrode packs into the casing also increases. The electrode packs are prone to collisions with the casing during the insertion process, which can lead to damage. On the other hand, due to their strength issues, the electrode packs often bend and deform, and the electrode sheets may have defects such as wrinkles, deformation, delamination, and breakage, resulting in a decrease in yield.

[0041] To alleviate the difficulty of mounting the electrode assembly due to its increased length, a solution has been proposed that a single electrode assembly arranged along the length of the battery be divided into multiple electrode components, each installed inside the cell casing. While this approach reduces the overall mounting difficulty to some extent, additional connecting structures are typically required for electrical connection between the electrode components. These connecting structures inevitably occupy internal space, compressing the effective arrangement space of the electrode components and consequently negatively impacting the cell capacity.

[0042] To address the aforementioned issues, the inventors proposed arranging multiple electrode components sequentially along the length of the battery cell, with the opposing end faces of adjacent electrode components electrically connected via a conductive coating. Specifically, in each electrode component, the stacked positive electrode plates collectively form a positive end face for electrical connection with adjacent electrode components; similarly, the stacked negative electrode plates collectively form a negative end face for electrical connection with adjacent electrode components. The positive end faces of adjacent electrode components face each other along the electrode component arrangement direction and are electrically connected via the conductive coating; similarly, the negative end faces of adjacent electrode components also face each other along the electrode component arrangement direction and are electrically connected via the conductive coating. This allows for reliable electrical connection between electrode components without additional connecting components occupying internal space, effectively improving the utilization of internal space and contributing to increased battery cell capacity.

[0043] Based on this, refer to Figure 1 and Figure 2 In this embodiment, the battery cell includes a housing 1, a first electrode group 2, and a second electrode group 3. Both the first electrode group 2 and the second electrode group 3 are disposed inside the housing 1. The first electrode group 2 and the second electrode group 3 are arranged sequentially along the Y direction (i.e., the length direction of the housing 1).

[0044] The first electrode group 2 comprises multiple first positive electrode sheets and multiple first negative electrode sheets stacked along the Z-direction. The multiple first positive electrode sheets, along the Y-direction towards the end of the second electrode group 3, collectively form a first positive terminal surface 206, and the multiple first negative electrode sheets, along the Y-direction towards the end of the second electrode group 3, collectively form a first negative terminal surface 207. The second electrode group 3 comprises multiple second positive electrode sheets and multiple second negative electrode sheets stacked along the Z-direction. The multiple second positive electrode sheets, along the Y-direction towards the end of the first electrode group 2, collectively form a second positive terminal surface 306, and the multiple second negative electrode sheets, along the Y-direction towards the end of the first electrode group 2, collectively form a second negative terminal surface 307.

[0045] The first positive terminal 206 and the second positive terminal 306, as well as the first negative terminal 207 and the second negative terminal 307, are electrically connected by a conductive coating 5 to achieve electrical connection between the first electrode group 2 and the second electrode group 3.

[0046] Therefore, in this embodiment, the first electrode group 2 and the second electrode group 3 are arranged sequentially along the length of the cell, and positive and negative end faces for electrical connection with adjacent electrode groups are formed at the ends of each electrode group, and the electrical connection is finally achieved through the conductive coating 5. Compared with related technologies, this embodiment does not require additional intermediate connection structures, which not only effectively reduces the space occupied by ineffective structures inside the housing 102, but also improves the space utilization rate of the electrode groups within the housing 102, thereby increasing the cell capacity.

[0047] In one embodiment, along the Y direction, a first protrusion 203 and a second protrusion 204 are formed at one end of the first electrode group 2 facing the second electrode group 3. The end face of the first protrusion 203 along the Y direction is the first positive end face 206, and the end face of the second protrusion 204 along the Y direction is the first negative end face 207. The first protrusion 203 and the second protrusion 204 are spaced apart along the X direction, and the space between them forms a first clearance groove 201. The first clearance groove 201 penetrates the first electrode group 2 along the Z direction.

[0048] Therefore, in this embodiment, a local gap region is formed between the first electrode group 2 and the second electrode group 3. On the one hand, it provides a storage space 6 for the electrolyte, which is conducive to the collection and replenishment of the electrolyte in the end region of the electrode group. On the other hand, it can improve the penetration and wetting conditions of the electrolyte into the electrode group, thereby improving the overall wetting consistency of the electrode sheet, reducing the risk of increased polarization or performance degradation due to insufficient wetting, and thus helping to improve the electrochemical performance stability and reliability of the battery cell.

[0049] In one embodiment, reference Figure 4 and Figure 10 As shown, along the Y direction, the second electrode group 3 has a third protrusion 301 and a fourth protrusion 302 formed at one end facing the first electrode group 2, corresponding one-to-one with the first protrusion 203 and the second protrusion 204 in the first electrode group 2. Specifically, the end face of the third protrusion 301 along the Y direction constitutes the second positive terminal face 306, and the end face of the fourth protrusion 302 along the Y direction constitutes the second negative terminal face 307. Therefore, in this embodiment, the end faces of the first protrusion 203 and the third protrusion 301, and the end faces of the second protrusion 204 and the fourth protrusion 302 are electrically connected by conductive coatings 5, thereby forming a stable and reliable electrical connection between the first electrode group 2 and the second electrode group 3.

[0050] Furthermore, the third protrusion 301 and the fourth protrusion 302 are spaced apart along the X direction, and the space between them forms a second clearance groove 303. The second clearance groove 303 penetrates the second electrode group 3 along the Z direction (i.e., the thickness direction of the outer shell 1 and the electrode group). By setting the second clearance groove 303 in the second electrode group 3, the local gap area between the first electrode group 2 and the second electrode group 3 can be further expanded, thereby forming a larger liquid storage space 6 at the end of the electrode group. This is beneficial for the collection, flow and replenishment of electrolyte, and further improves the overall wetting effect of the electrode group.

[0051] The second clearance groove 303 and the first clearance groove 201 are arranged opposite each other along the Y direction. Figure 10 As shown, the opening of the first venting channel 201 along the Y direction is aligned with and connected to the opening of the second venting channel 303 along the Y direction, so that the first venting channel 201 and the second venting channel 303 form a connected liquid storage channel, thereby further improving the consistency, safety and cycle stability of the battery cell.

[0052] It should be noted that the first protrusion 203 and the third protrusion 301 are not formed by additional structures, but are naturally formed by the structure of the electrode itself and the stacking method. Specifically, along the Y direction, the first positive electrode in the first electrode group 2 has a partially protruding portion relative to the first negative electrode. After multiple first positive electrodes are stacked along the Z direction, their corresponding protruding portions are superimposed along the Z direction, thereby forming the aforementioned first protrusion 203. Similarly, the second positive electrode in the second electrode group 3 also has a partially protruding portion relative to the second negative electrode. After multiple second positive electrodes are stacked, their protruding portions are superimposed along the Z direction, thereby forming the aforementioned third protrusion 301.

[0053] Correspondingly, the second protrusion 204 and the fourth protrusion 302 are also formed by the protruding structure of the negative electrode itself. Specifically, along the Y direction, the first negative electrode in the first electrode group 2 has a partially protruding portion relative to the first positive electrode. After multiple first negative electrodes are stacked along the Z direction, their protruding portions are superimposed along the Z direction, thereby forming the aforementioned second protrusion 204; similarly, the second negative electrode in the second electrode group 3 has a partially protruding portion relative to the second positive electrode. After multiple second negative electrodes are stacked, their protruding portions are superimposed along the Z direction, thereby forming the aforementioned fourth protrusion 302. Therefore, in this embodiment, the above-mentioned protrusions are all directly formed by the electrode body, without the need for additional independent conductive or supporting components, further improving the utilization rate of the internal space of the outer casing 1.

[0054] In one embodiment, reference Figure 3 Along the X direction (i.e., the width direction of the outer shell 1), first protrusions 202 are formed on both sides of the first pole group 2; combined with Figure 4The second electrode group 3 has a second protrusion 304 formed on both sides to effectively expand the effective volume of the first electrode group 2 and the second electrode group 3, thereby increasing the overall capacity of the battery cell.

[0055] Furthermore, combined Figure 2 As shown, along the Y direction, the first protrusion 202 and the second protrusion 304 are spaced apart, and along the X direction, a space is formed between the first protrusion 202 and the second protrusion 304 on the same side, which constitutes a liquid storage space 6. Therefore, by forming liquid storage spaces 6 on both sides of the first electrode group 2 and the second electrode group 3 along the X direction, the electrolyte can be fully collected and replenished on the side of the electrode group, thereby further improving the overall wetting effect of the electrode group and enhancing the consistency and stability of the electrochemical reaction.

[0056] In one embodiment, reference Figure 5 Along the Y direction, the distance between the first boss 202 and the end face of the first pole group 2 facing the second pole group 3, and the distance between the second boss 304 and the end face of the second pole group 3 facing the first pole group 2 are both W1, and satisfy 18mm≤W1≤60mm, for example 18mm, 36mm or 51mm.

[0057] When W1 is less than 18mm, the liquid storage space 6 formed laterally by a single electrode group will be insufficient, and the electrolyte's ability to collect in this area will be limited, making it difficult to significantly improve the electrode group's wetting effect. When W1 is greater than 60mm, although a larger liquid storage space 6 can be obtained, it will inevitably compress the volume of the electrode group corresponding to the first protrusion 202 and the second protrusion 304, resulting in a limited increase in the effective volume of the electrode group, which is not conducive to further improving the cell capacity.

[0058] In one embodiment, reference Figure 5 and Figure 6 Along the X direction, the distance between the first protrusions 202 on both sides of the first pole group 2 is A, and the length of the two sides of the first pole group 2 is F. The two satisfy 6mm≤AF≤12mm, for example 6mm, 10mm or 12mm.

[0059] When AF is less than 6mm, the depth of the electrolyte storage space formed by a single electrode group along the X direction is insufficient, and the improvement of electrolyte wetting effect is limited; when AF is greater than 12mm, the effective volume of the electrode group along the X direction is greatly reduced, significantly reducing the electrode group capacity and affecting the energy density of the cell.

[0060] In one embodiment, an explosion-proof valve 101 is provided on the outer casing 1 to promptly release high-temperature gas when the internal pressure of the battery cell abnormally increases, thereby reducing the internal pressure, preventing structural rupture or explosion of the casing 102, and ensuring the safe use of the battery cell and battery system. (Reference) Figure 1 and Figure 2The explosion-proof valve 101 is correspondingly provided with the above-mentioned liquid storage space 6 and is connected to the liquid storage space 6, so that the gas can be discharged from the outer shell 1 through the liquid storage space 6 and the explosion-proof valve 101, thereby avoiding the direct action of high temperature and high pressure gas on the electrode group area.

[0061] In one embodiment, the outer casing 1 includes a housing 102, on which two first shell walls opposite each other along the X direction are respectively formed a third groove 107 and a fourth groove 108 for accommodating a first boss 202 and a second boss 304. (Reference) Figure 1 The bottoms of the third groove 107 and the fourth groove 108 protrude outward relative to the outer casing 1 along the X direction, forming reinforcing protrusions on both sides of the outer casing 1 along the X direction, thereby improving the structural strength of the sidewalls of the outer casing 1. Simultaneously, the explosion-proof valve 101 is disposed between the third groove 107 and the fourth groove 108, thus forming a force-bearing support structure on both sides of the explosion-proof valve 101, which helps reduce the risk of damage to the explosion-proof valve 101 under external forces.

[0062] In one embodiment, along the Y direction, the opposite end faces of the first electrode group 2 and the second electrode group 3 are each provided with a fifth protrusion 7 and a sixth protrusion 8 to further increase the effective volume of the first electrode group 2 and the second electrode group 3, thereby obtaining a cell with higher capacitance. Along the X direction, the fifth protrusion 7 and the sixth protrusion 8 are spaced apart. The housing 1 includes a housing 102 and cover plates 106 disposed at both ends of the housing 102 along the Y direction. The cover plates 106 can be connected to the housing 102 by welding, forming an installation space inside the housing 102 for accommodating the first electrode group 2 and the second electrode group 3.

[0063] refer to Figure 8 and Figure 9 The cover plate 106 is provided with a fifth groove 1061 and a sixth groove 1062 for accommodating the fifth protrusion 7 and the sixth protrusion 8. The fifth groove 1061 and the sixth groove 1062 may also have protruding portions that protrude outward from the cover plate 106 along the Y direction, thereby improving the structural strength of the cover plate 106 along the Y direction and effectively preventing the poles on the cover plate 106 from deforming or being damaged due to stress.

[0064] Combination Figure 6 Along the Z direction, the distance between the two sides of the fifth protrusion 7 is K, and the distance between the two sides of the first pole group 2 is B2, satisfying 0.35≤K / B2≤0.7, for example 0.35, 0.55 or 0.70.

[0065] When K / B2 is less than 0.35, the proportion of the fifth boss 7 on the end face of the first pole group 2 is too small, resulting in insufficient thickness of the fifth boss 7 and limited capacity improvement. When K / B2 is greater than 0.7, the thickness of the fifth boss 7 is too large, which will significantly increase the stamping difficulty of the cover plate 106 and lead to increased manufacturing costs.

[0066] In this embodiment, the fifth and sixth bosses have the same structure and dimensions.

[0067] In one embodiment, along the Y direction, the end face of the first electrode group 2 facing away from the second electrode group 3 includes a central plane 10 and inclined planes 4 located on both sides of the plane 10 along the X direction, with the ends of the two inclined planes 4 away from the plane 10 moving away from each other along the X direction. Figure 5 In the projection along the Z direction, the ends of the first pole group 2 are generally in a "figure-eight" shape.

[0068] Along the Y-direction, the end face of the first electrode group 2 facing away from the second electrode group 3 is provided with a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate; along the Z-direction, the positive and negative electrode tabs are located on both sides of the fifth protrusion 7 and the sixth protrusion 8, respectively. The two ends of the positive and / or negative electrode tabs extend to the two inclined surfaces 4 along the X-direction, thereby effectively increasing the length of the electrode tab 9, which is beneficial for current dispersion and heat release, and avoids excessive local temperature rise of the electrode tab 9 under fast charging conditions. Therefore, referring to... Figure 3 and Figure 4 The tabs 9 each include a straight segment 901 parallel to the plane 10 and an inclined segment 902 parallel to the inclined plane 4. Accordingly, refer to... Figure 8 and Figure 9 The cover plate 106 is also configured with a “figure-eight” structure that matches the end of the pole group.

[0069] In one embodiment, along the X direction, the length of the central plane 10 is L3, and the distance between the two opposing sides of the fifth boss 7 and the sixth boss 8 is L2, satisfying 0mm≤L3. L2≤16mm, for example 0mm, 11mm or 16mm.

[0070] When L3 When L2 is too small, the limiting effect of the fifth protrusion 7 and the sixth protrusion 8 in the X direction is insufficient, which is not conducive to the stable installation of the pole group; when L3 is too small... When L2 is too large, it will cause the proportion of the protrusion size at the end of the electrode group to be too high, which will affect the volume utilization rate of the electrode group.

[0071] In one embodiment, the included angle between the two inclined planes 4 of the first pole group 2 is N, which satisfies 50°≤N≤110°, for example 50°, 80° or 110°.

[0072] When N is less than 50°, the included angle between the two inclined planes 4 is too small, which will limit the effective length of the tab 9 extending along the inclined plane 4, which is not conducive to current dispersion and heat dissipation, and is prone to local overheating under fast charging or high current conditions.

[0073] When N is greater than 110°, the included angle between the two inclined planes 4 is too large, and the end of the first pole group 2 tends to be a straight structure, which weakens the guiding and supporting effect of the inclined plane 4 on the pole lug 9. This is not conducive to the pole lug 9 unfolding along the inclined plane 4 and increasing its effective length, and may affect the assembly matching between the cover plate 106 and the pole group.

[0074] In one embodiment, reference Figure 2 and Figure 5 Along the Z-direction, the two surfaces of the first electrode group 2 are provided with a third protrusion 205 to further increase the volume of the first electrode group 2. Along the Y-direction, the end face of the third protrusion 205 facing away from the second electrode group 3 is coplanar with the end face of the first electrode group 2 facing away from the second electrode group 3, which facilitates the smooth installation of the first electrode group 2 into the outer casing 1. The two surfaces of the second electrode group 3 along the Z-direction are also provided with a fourth protrusion 305, the structure and function of which correspond to the third protrusion 205.

[0075] The outer casing 1 includes a housing 102. Along the Z-direction, two opposing second shell walls of the housing 102 are respectively formed with a first groove 103 for accommodating a third protrusion 205 and a second groove 104 for accommodating a fourth protrusion 305. The outer surface of the second shell wall away from the pole group is respectively formed with a first protrusion 1031 and a second protrusion 1041 corresponding to the first groove 103 and the second groove 104, so as to enhance the structural strength of the sidewall of the housing 102 in the Z-direction.

[0076] Along the Y direction, the third protrusion 205 and the fourth protrusion 305 are spaced apart, and a gap is formed between the first protrusion 1031 and the second protrusion 1041. A cooling plate 105 is provided in the outer casing 1, which is arranged within the gap and forms a medium channel inside. By introducing a cooling medium into the medium channel, the electrode group is effectively cooled. Since this cooling area corresponds to the electrical connection position between the first electrode group 2 and the second electrode group 3, the resistance is large and the heat generation is concentrated at this position. The cooling medium directly exchanges heat with it, which helps to suppress local temperature rise and improve the safety of the battery cell.

[0077] It should be mentioned that, in this embodiment, reference is made to... Figure 1 and Figure 2 The aforementioned first protrusion 202, second protrusion 304, third protrusion 205, and fourth protrusion 305 can all interact with corresponding grooves on the outer casing 1, serving a guiding function when the first pole group 2 and the second pole group 3 are installed inside the outer casing 1. Simultaneously, after installation, the first protrusion 202, second protrusion 304, third protrusion 205, and fourth protrusion 305 form a limiting structure with their corresponding grooves, thereby imposing limiting constraints on the first pole group 2 and the second pole group 3, thus preventing the first pole group 2 and the second pole group 3 from moving relative to the outer casing 1.

[0078] In this embodiment, a medium inlet and an outlet can be provided on the cooling plate 105 to form a circulating flow between the medium channel and the external cooling system, thereby further enhancing the heat dissipation effect.

[0079] Cooling channels can take various structural forms. (See reference) Figure 7 and Figure 11 Along the Y direction, the third boss 205 includes a first body portion and a first support portion disposed toward the fourth boss 305. The thickness of the first support portion in the Z direction is less than that of the first body portion, thereby forming a first ladder 1032. The fourth boss 305 includes a second body portion and a second support portion, with the second support portion forming a second ladder. The cooling plate 105 includes a straight section 901 and vertical sections 901 located on both sides of the straight section 901. The straight section 901 abuts against the first ladder 1032 and the second ladder, and the vertical section 901 abuts against the inner wall of the housing 102 along the Z direction, together with the housing 102 enclosing a medium channel.

[0080] At the same time, refer to Figure 1 and Figure 5 The opposite sides of the first boss 202 and the second boss 304 are coplanar with the side edges of the first pole group 2 and the second pole group 3 along the X direction, respectively, thus playing a guiding role during pole group installation. After installation, the first boss 202 and the third groove 107, and the second boss 304 and the fourth groove 108 form a limiting fit, restricting the displacement of the pole group within the housing 102. Similarly, the third boss 205 and the fourth boss 305 also form a circumferential limiting structure with their corresponding grooves, thereby constraining the first pole group 2 and the second pole group 3 in multiple directions and improving assembly stability.

[0081] In one embodiment, reference Figure 5 and Figure 6 Along the Y direction, the distance between the third protrusion 205 and the end face of the first pole group 2 facing the second pole group 3 is W2, and the length of the first pole group 2 along the Y direction is E, which satisfies 250mm≤E≤600mm and 0.15≤W2 / E≤0.33.

[0082] When W2 / E is less than 0.15, the length of the third protrusion 205 is insufficient, which limits the size of the corresponding cooling structure and results in poor cell cooling. When W2 / E is greater than 0.33, the length of the third protrusion 205 is too large, which will limit the increase in its protrusion size and affect the increase in electrode volume.

[0083] In one embodiment, along the X direction, the distance between the two sides of the third boss 205 is L1, and the distance between the two sides of the first pole group 2 is A, satisfying 0.33≤L1 / A≤0.7.

[0084] When L1 / A is less than 0.33, it indicates that the dimension of the third protrusion 205 in the X direction is insufficient relative to the overall width of the first electrode group 2. The volume increase of the third protrusion 205 is limited, making it difficult to effectively increase the volume of the electrode group while taking into account structural reinforcement, heat dissipation, and limiting functions. Its effect on improving cell capacity and structural stability is limited.

[0085] When L1 / A is greater than 0.7, the size of the third boss 205 in the first pole group 2 is too large. Correspondingly, the size of the first groove 103 on the outer shell 1 that matches it also needs to be increased. This will not only significantly increase the difficulty of stamping or forming the aluminum shell and cover plate 106, but also increase the amount of material used and the complexity of processing, thereby increasing the manufacturing cost and having an adverse effect on product consistency and yield.

[0086] Along the Z direction, the distance between the third protrusions 205 located on both sides of the first pole group 2 is B1, and the distance between the two surfaces of the first pole group 2 along the Z direction is B2. The two satisfy 20mm≤B1-B2≤60mm, for example 20mm, 50mm or 60mm.

[0087] When B1-B2 is less than 20mm, the protrusion height of the third boss 205 in the Z direction is insufficient, making it difficult to significantly increase the effective volume of the electrode assembly. At the same time, the limiting and supporting effect formed between it and the corresponding first groove 103 of the housing 102 is weak, which is not conducive to the stable fixation of the electrode assembly in the housing 102.

[0088] When B1-B2 is greater than 60mm, the protrusion height of the third boss 205 in the Z direction is too large, which will significantly increase the structural size requirements of the pole group and the outer shell 1 in this direction, resulting in increased molding difficulty of the side wall of the outer shell 102 and the corresponding groove, and increased material usage and manufacturing cost.

[0089] Table 1

[0090] In this embodiment, the first electrode group 2 and the second electrode group 3 can be set to be identical in terms of structural form and dimensional parameters, thereby achieving consistent technical effects. This embodiment uses the aforementioned first electrode group 2 as an example to illustrate the relevant technical solutions and their beneficial effects. To avoid redundancy, the second electrode group 3 will not be described again.

[0091] Although embodiments of the 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 invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: shell; A first electrode group and a second electrode group are disposed within the outer casing, arranged sequentially along the Y direction. The first electrode group includes a plurality of first positive electrode plates and a plurality of first negative electrode plates stacked along the Z direction. The plurality of first positive electrode plates together form a first positive terminal face along the Y direction towards one end of the second electrode group, and the plurality of first negative electrode plates together form a first negative terminal face along the Y direction towards one end of the second electrode group. Along the Y direction, the end face of the first electrode group opposite to the second electrode group is provided with a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate. The second electrode group includes a plurality of second positive electrode plates and a plurality of second negative electrode plates stacked along the Z direction. The plurality of second positive electrode plates together form a second positive electrode end face along the Y direction toward one end of the first electrode group, and the plurality of second negative electrode plates together form a second negative electrode end face along the Y direction toward one end of the first electrode group. The first positive terminal face and the second positive terminal face, as well as the first negative terminal face and the second negative terminal face, are electrically connected by a conductive coating. Along the X direction, a first protrusion is formed on both sides of the first electrode group, and a second protrusion is formed on both sides of the second electrode group. Along the Y direction, the first protrusion and the second protrusion are spaced apart, and the space between the first protrusion and the second protrusion located on the same side along the X direction forms a liquid storage space. An explosion-proof valve is provided on the outer shell. Along the X direction, the explosion-proof valve is correspondingly arranged with the liquid storage space and is connected to the liquid storage space. The outer shell includes a shell. The two opposite first shell walls of the shell along the X direction are each formed with a third groove and a fourth groove for accommodating the first boss and the second boss. The bottom of the third groove and the fourth groove along the X direction protrudes outward relative to the outer shell.

2. The battery cell according to claim 1, characterized in that, Along the Y direction, the first pole group has a first protrusion and a second protrusion at one end facing the second pole group. The end face of the first protrusion along the Y direction is the first positive end face, and the end face of the second protrusion along the Y direction is the first negative end face. The first protrusion and the second protrusion are spaced apart along the X direction, and the space between them forms a first clearance groove, which penetrates the first pole group along the Z direction.

3. The battery cell according to claim 2, characterized in that, Along the Y direction, the end of the second electrode group facing the first electrode group has a third protrusion and a fourth protrusion. The end face of the third protrusion along the Y direction is the second positive end face, and the end face of the fourth protrusion along the Y direction is the second negative end face. The third protrusion and the fourth protrusion are spaced apart along the X direction, and the space between them forms a second clearance groove. The second clearance groove passes through the second pole group along the Z direction, and the second clearance groove and the first clearance groove are arranged opposite to each other along the Y direction.

4. The battery cell according to claim 1, characterized in that, Along the Y direction, the distance from the first boss to the end face of the first pole group facing the second pole group, and the distance from the second boss to the end face of the second pole group facing the first pole group, are both W1. Where 18mm≤W1≤60mm.

5. The battery cell according to claim 4, characterized in that, Along the X direction, the distance between the first protrusions on both sides of the first pole group is A, and the distance between the two sides of the first pole group is F, satisfying 6mm≤AF≤12mm.

6. The battery cell according to claim 5, characterized in that, The explosion-proof valve is located between the third groove and the fourth groove.

7. The battery cell according to claim 4, characterized in that, Along the Y direction, the end faces of the first electrode group and the second electrode group that are opposite to each other are provided with a fifth protrusion and a sixth protrusion. Along the X direction, the fifth protrusion and the sixth protrusion are spaced apart. The outer shell includes a shell and cover plates located at both ends of the shell along the Y direction. The cover plates include a fifth groove and a sixth groove for accommodating the fifth protrusion and the sixth protrusion, respectively. Along the Z direction, the distance between the two sides of the fifth protrusion is K, and the distance between the two sides of the first pole group is B2, satisfying 0.35≤K / B2≤0.

7.

8. The battery cell according to claim 7, characterized in that, Along the Y direction, the end face of the first electrode group away from the second electrode group includes a plane and inclined surfaces located on both sides of the plane along the X direction. The ends of the two inclined surfaces away from the plane are configured to be far apart from each other along the X direction. Along the Y direction, the end face of the first electrode group away from the second electrode group is provided with a positive electrode tab connected to the positive electrode plate and a negative electrode tab connected to the negative electrode plate. Along the Z direction, the positive electrode tab and the negative electrode tab are located on both sides of the fifth protrusion and the sixth protrusion, respectively. The two ends of the positive electrode tab and / or the negative electrode tab along the X direction extend to the two inclined surfaces, respectively.

9. The battery cell according to claim 8, characterized in that, Along the X direction, the length of the plane is L3, and the distance between the two opposite sides of the fifth and sixth protrusions is L2, satisfying 0mm≤L3-L2≤16mm; And / or, The angle between the two inclined planes is N, which satisfies 50°≤N≤110°.

10. The battery cell according to claim 1, characterized in that, Along the Z direction, a third protrusion is provided on both surfaces of the first electrode group. Along the Y direction, the end face of the third protrusion facing away from the second electrode group is coplanar with the end face of the first electrode group facing away from the second electrode group. A fourth protrusion is provided on each surface of the second electrode group along the Z direction. Along the Y direction, the end face of the fourth protrusion facing away from the first electrode group is coplanar with the end face of the second electrode group facing away from the first electrode group. The outer casing includes a housing, and along the Z direction, a first groove for accommodating the third boss and a second groove for accommodating the fourth boss are formed on two opposing second shell walls of the housing; Along the Z direction, the outer surface of the second shell wall away from the first pole group has a first protrusion corresponding to the first groove and a second protrusion corresponding to the second groove. Along the Y direction, the third protrusion and the fourth protrusion are spaced apart. The first protrusion and the second protrusion are spaced apart and form a gap space. The shell includes a cooling plate, which is disposed in the gap space. The cooling plate has a medium channel inside. Along the Y direction, the distance between the third protrusion and the end face of the first pole group facing the second pole group is W2, and the length of the first pole group along the Y direction is E, satisfying: 250mm≤E≤600mm, 0.15≤W² / E≤0.33; Along the X direction, the distance between the two sides of the third protrusion is L1, and the distance between the two sides of the first pole group is A, satisfying: 0.33≤L1 / A≤0.7; Along the Z-direction, the distance between the third protrusions located on both sides of the first pole group is B1, and the distance between the two surfaces of the first pole group along the Z-direction is B2, satisfying: 20mm≤B1-B2≤60mm.

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