Battery cell, preparation process thereof and energy storage equipment

Abstract

The invention relates to the technical field of energy storage, in particular to a battery cell and a preparation process thereof and energy storage equipment, the battery cell comprises a top cover structure, the top cover structure comprises a pole column, the pole column comprises a main body part, a first bending part and a second bending part, the first bending part and the second bending part are arranged on the two sides of the main body part in the height direction of the battery cell, and the first bending part and the second bending part horizontally extend in the width direction; in the width direction, the extension directions of the first bending part and the second bending part of which the projections are positioned on the same straight line are opposite in the width direction; in the length direction, the bending directions of the adjacent first bending parts in the width direction are opposite, and the bending directions of the adjacent second bending parts in the width direction are opposite; the length of the pole accounts for more than or equal to 10% of the length of the battery cell; polishing an aluminum sheet; the connecting piece is provided with first connecting holes which are distributed in a staggered mode, the second bending parts are connected with the first connecting holes in a clamped mode, and the second bending parts do not protrude out of the surface of the connecting piece. According to the battery cell provided by the invention, the current bearing capacity of the pole is improved, and meanwhile, the connection stability of the pole and the connecting sheet is ensured.

Description

[0001] This application is a divisional application. The application number of the original application is 202411491485.9, the original application date is October 23, 2024, and the entire content of the original application is incorporated herein by reference.

Technical Field

Background Art

[0004] However, when the electric core uses a pole column with a large size, the large-size pole column and the connecting piece are welded along the circumferential edge of the pole column, and the connection stability between the two is poor, which easily affects the output voltage and efficiency of the electric core.

Summary of the Invention

[0006] In a first aspect, this application provides an electric core, including a top cover structure, and the top cover structure includes: A pole column, including a main body part, a first bending part, and a second bending part; wherein, along the height direction of the electric core, the first bending part and the second bending part are respectively arranged on both sides of the main body part and horizontally extend along the width direction of the electric core; along the width direction of the electric core, the first bending part and the second bending part whose projections are located on the same straight line extend in opposite directions in the width direction of the electric core; along the length direction of the electric core, the adjacent first bending parts have opposite bending directions in the width direction of the electric core, and the adjacent second bending parts have opposite bending directions in the width direction of the electric core; the length of the pole column accounts for a proportion ≥ 10% of the length of the electric core; A light aluminum sheet, provided with a mounting hole, the main body part of the pole column passes through the mounting hole, and along the height direction of the electric core, the first bending part and the second bending part are respectively located on both sides of the mounting hole; The connecting piece is provided with first connecting holes distributed in a staggered manner, and the second bent portion of the pole post is clamped with the first connecting holes, and the second bent portion does not protrude from the surface of the connecting piece away from the light aluminum sheet.

[0007] In some embodiments, along the length direction of the battery cell, the length of the pole post is 10 mm to 100 mm.

[0008] In some embodiments, along the length direction of the battery cell, the widths of the first bent portion and the second bent portion are 1 mm to 10 mm.

[0009] In some embodiments, along the width direction of the battery cell, the extending lengths of the first bent portion and the second bent portion are 0.5 mm to 5 mm.

[0010] In some embodiments, along the length direction of the battery cell, the spacing distances between adjacent first bent portions are 0.17 mm to 3.4 mm, and the spacing distances between adjacent second bent portions are 0.17 mm to 3.4 mm.

[0011] In some embodiments, after the connecting piece is clamped with the second bent portion, they are connected by welding.

[0012] In a second aspect, the present application provides a preparation process for a battery cell, including the assembly process of the top cover structure, and the assembly process of the top cover structure includes: Prepare the pole post, the light aluminum sheet and the connecting piece; wherein, the pole post includes a main body portion, a first extending portion and a second extending portion, and along the height direction of the battery cell, the first extending portion and the second extending portion are respectively arranged at both ends of the main body portion; the light aluminum sheet is provided with mounting holes, and the connecting piece is provided with first connecting holes distributed in a staggered manner; The main body portion of the pole post penetrates into the mounting holes of the light aluminum sheet, and the first extending portion is bent to form a first bent portion, and the second extending portion is bent to form a second bent portion; wherein, the bending directions of the first bent portion and the second bent portion in the width direction of the battery cell are opposite; and along the length direction of the battery cell, the bending directions of adjacent first bent portions in the width direction of the battery cell are opposite, and the bending directions of adjacent second bent portions in the width direction of the battery cell are opposite; Clamp the first connecting holes of the connecting piece with the second bent portion of the pole post, and the second bent portion does not protrude from the surface of the connecting piece away from the light aluminum sheet.

[0013] In some embodiments, the assembly process of the top cover structure further includes: Weld the edge of the second bent portion of the pole post and the first connecting hole of the connecting piece.

[0014] In a third aspect, the present application provides an energy storage device, which includes a battery management system, an energy storage inverter, an energy management system, and a battery pack. The battery pack includes a plurality of battery cells prepared by the preparation process of the battery cells according to any one of the first aspect or the battery cells according to any one of the second aspect.

[0015] In some embodiments, the battery pack further includes a tab. The battery cell is connected to an external circuit through the tab. The tab is provided with second connection holes distributed in a staggered manner. The first bent portion of the pole column of the battery cell is clamped with the second connection hole, and the first bent portion does not protrude from the surface of the tab away from the light aluminum sheet.

[0016] Adopting the above technical solutions, at least the following beneficial effects are achieved: For the battery cell of the present application, the ratio of the length of the pole column to the length of the battery cell is ≥ 10%, that is, the pole column is of a larger size. The pole column of a larger size has higher mechanical strength, lower contact resistance, and greater current-carrying capacity. Moreover, the pole column of a larger size has better heat dissipation performance, which can ensure that the battery cell operates within a safe temperature range. At the same time, the pole column is provided with a second bent portion, and along the length direction of the battery cell, the adjacent second bent portions are bent in opposite directions in the width direction of the battery cell, and the connection holes are distributed in a staggered manner in the connection piece. When the battery cells are assembled, the second bent portion of the pole column can be clamped with the connection hole to ensure the connection stability between the pole column and the connection piece.

Description of the Drawings

[0018] Reference numerals in the drawings: 1. Top cover structure; 11. Pole; 111. Main body part; 112. First bent part; 113. Second bent part; 12. Light aluminum sheet; 121. Mounting hole; 13. Connecting piece; 131. First connection hole; 132. Welding position; 14. Connection area; 141. First area; 142. Second area; 15. Sealing ring; 161. First pressing block; 162. Second pressing block; 17. Insulating sheet; 2. Bare battery cell; 21. Bottom support sheet; 3. Housing; 4. Insulating film; 41. Film main body; 42. Extension part; 421. First extension part; 422. Second extension part; 43. First part; 44. Second part; 5. Tab; 51. Second connection hole.

Detailed implementation manners

[0020] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0021] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should be understood that the term " / and" used herein is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0023] It should be noted that the orientation terms such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described from the angles shown in the drawings, and should not be construed as a limitation on the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0024] In the battery cell of the energy storage device, the top cover structure is connected to the bare battery cell in the housing through the cooperation of the pole column and the connecting piece. Among them, the pole column is a key component connecting the internal electrode of the battery cell and the external circuit, and is responsible for functions such as electrical connection, current carrying, thermal management, and mechanical fixation.

[0025] With the increase of the battery cell capacity, large-capacity battery cells need to carry a larger current during charging and discharging. In order to ensure that the current can pass through the pole column stably, pole columns with larger sizes are required to reduce the contact resistance and improve the current carrying capacity. However, when large-sized pole columns are used in the battery cell, the large-sized pole columns and the connecting piece are welded along the circumferential edge of the pole column, and the connection stability between them is poor, which is likely to affect the output voltage and efficiency of the battery cell.

[0026] In view of this, the present application provides a battery cell, including a top cover structure 1. Please refer to Figures 1 to 12 , and the top cover structure 1 includes: The pole column 11 includes a main body portion 111, a first bending portion 112, and a second bending portion 113. Among them, along the height direction of the battery cell, the first bending portion 112 and the second bending portion 113 are respectively arranged on both sides of the main body portion 111 and horizontally extend along the width direction of the battery cell. Along the width direction of the battery cell, the first bending portion 112 and the second bending portion 113 whose projections are located on the same straight line extend in opposite directions along the width direction of the battery cell. Along the length direction of the battery cell, the adjacent first bending portions 112 bend in opposite directions along the width direction of the battery cell, and the adjacent second bending portions 113 bend in opposite directions along the width direction of the battery cell. The length of the pole column 11 accounts for a proportion of ≥10% of the length of the battery cell. The light aluminum sheet 12 is provided with a mounting hole 121. The main body portion 111 of the pole column 11 passes through the mounting hole 121, and along the height direction of the battery cell, the first bending portion 112 and the second bending portion 113 are respectively located on both sides of the mounting hole 121. The connecting piece 13 is provided with first connecting holes 131 distributed in a staggered manner. The second bending portion 113 of the pole column 11 is clamped with the first connecting holes 131, and the second bending portion 113 does not protrude from the surface of the connecting piece 13 away from the light aluminum sheet 12.

[0027] In the above solution, for the battery cell of the present application, the ratio of the length of the terminal 11 to the length of the battery cell ≥ 10%. Further, the total length of the positive and negative terminals accounts for ≥ 10% of the length of the battery cell, that is, the terminal 11 is of a larger size. The terminal 11 of a larger size has higher mechanical strength, lower contact resistance, and greater current-carrying capacity. Moreover, the terminal 11 of a larger size has better heat dissipation performance, which can ensure that the battery cell operates within a safe temperature range. At the same time, the terminal 11 is provided with a second bending portion 113, and along the length direction of the battery cell, the bending directions of adjacent second bending portions 113 in the width direction of the battery cell are opposite, and the connecting piece 13 is provided with first connecting holes 131 distributed in a staggered manner. When the battery cell is assembled, the second bending portion 113 of the terminal 11 can be engaged with the first connecting holes 131 to ensure the connection stability between the terminal 11 and the connecting piece 13.

[0028] In some embodiments, the energy storage device is specifically assembled from a battery pack, a battery management system, a power conversion system, and an energy management system, and the energy storage device can be used to store and release electric energy. Among them, the battery pack is used to provide a stable power output; the battery management system (Battery Management System, BMS) is a key component for monitoring, controlling, and protecting the operating state of the battery pack, including parameters such as the voltage, current, and temperature of each battery cell in the battery pack, and prolongs the life of the battery pack and ensures the safe and stable operation of the entire energy storage system by means of equalizing charging, controlling the charging and discharging process, and protecting the battery pack from overcharging, over-discharging, overheating, short-circuiting, etc. The power conversion system (Power Conversion System, PCS) is one of the core components of the energy storage system and is responsible for converting direct current (DC) into alternating current (AC) or converting alternating current into direct current to achieve the storage and release of electric energy. The energy management system (Energy Management System, EMS) is a key component for monitoring, controlling, and optimizing the overall performance of the energy storage system, and is responsible for managing the energy exchange between the energy storage system and the power grid to ensure the high efficiency, economy, and safety of the system operation.

[0029] In addition to the above structure, the energy storage device also includes an electrical system and a thermal management system, etc. Among them, the electrical system includes all electrical components and circuits inside the energy storage device, such as the series and parallel connections between battery cells, the interfaces with inverters or chargers, the connection devices with the power grid or loads, control circuits, etc. The electrical system ensures efficient power conversion and transmission between the energy storage device and external power sources or loads. The thermal management system is a key system to ensure that the battery pack operates within a suitable temperature range, monitors and controls the internal temperature of the battery pack through components such as radiators, coolant, fans, and thermistors. When the battery generates heat during the charging and discharging process, the thermal management system can dissipate heat in a timely and effective manner to prevent performance degradation or safety problems caused by overheating of the battery.

[0030] The battery pack for providing a stable power output is composed of cells connected in series, parallel, or series-parallel. Among them, connecting cells in series can increase the total voltage of the battery pack, and connecting cells in parallel can increase the total capacity of the battery pack. The arrangement of cells can be selected according to the voltage and capacity requirements of the battery pack, which is not limited here.

[0031] In some embodiments, the cell generally includes a top cover structure 1, a bare cell 2, and a housing 3. Among them, the bare cell 2 is the core component of the cell, responsible for storing and releasing electrical energy, and is usually composed of a positive electrode material, a negative electrode material, an electrolyte, a separator, etc.; the housing 3 is the external package of the cell, usually made of materials such as metal or plastic, which can provide physical protection to prevent the internal bare cell 2 from being mechanically damaged, and at the same time isolate the internal bare cell 2 from the external environment to prevent moisture intrusion; the top cover structure 1 is responsible for connecting the bare cell 2 to the external circuit and providing a certain protective effect. During the production and assembly process, the bare cell 2 is placed inside the housing 3 and fixed to the bottom of the housing 3 through fixing devices such as screws and buckles, and the top cover structure 1 is connected to the top of the housing 3 by means of welding, bolt fixation, etc., thus assembling the cell.

[0032] The bottom surface of the top cover structure 1 is provided with a connection area 14, that is, the bottom of the lower plastic of the top cover structure 1 is provided with a connection area 14, and the distance between the connection area 14 and the center of the bottom surface of the top cover structure 1 is less than the distance between the edge of the top cover structure 1 and the center of the bottom surface of the top cover structure 1. Specifically, the connection area 14 is arranged at a certain distance from the top cover structure 1. The connection area 14 is an annular part arranged inside the lower plastic, specifically including a first area 141 arranged opposite along the width direction of the cell and a second area 142 arranged opposite along the length direction of the cell. The first area 141 and the second area 142 overlap at the corner area near the lower plastic. In this application, the widths of the first area 141 and the second area 142, as well as the distance between the annular part and the edge of the lower plastic, can be selected according to actual needs, which is not limited here.

[0033] The cell further includes an insulating film 4 covering the outside of the bare cell 2. The insulating film 4 includes a film main body 41 and an extension part 42. The film main body 41 covers the side wall and the bottom wall of the bare cell 2; the extension part 42 extends upward from the side wall of the film main body 41 and bends toward the center of the top surface of the bare cell 2 along the length direction and the width direction of the bare cell 2. Along the height direction of the bare cell 2, the extension part 42 is located between the connection area 14 and the top surface of the bare cell 2, and the upper surface of the extension part 42 is connected to the lower surface of the connection area 14. It can be understood that the main body part 111 can enclose to form a rectangular box with a receiving cavity. The bare cell 2 is received in the rectangular box, and the top of the bare cell 2 is flush with the top of the rectangular box. At this time, the extension part 42 is bent to complete the process of covering the bare cell 2.

[0034] The extension part 42 includes a first extension portion 421 arranged along the width direction of the battery cell and second extension portions 422 arranged oppositely along the length direction of the battery cell. When the bare battery cell 2 wrapped with the insulating film 4 is assembled with the housing 3 and the top cover structure 1, the first extension portion 421 is located between the first region 141 and the top surface of the bare battery cell 2, and the upper surface of the first extension portion 421 is connected to the first region 141; the second extension portions 422 are located between the second region 142 and the top surface of the bare battery cell 2, and the upper surface of the second extension portions 422 is connected to the second region 142.

[0035] The width of the first extension portion 421 is 2 mm to 8 mm, the width of the second extension portions 422 is 2 mm to 6 mm, and the width of the first extension portion 421 is greater than the width of the second extension portions 422. Optionally, the width of the first extension portion 421 can be 2 mm to 8 mm, 3 mm to 7 mm, 4 mm to 8 mm, or 5 mm to 6 mm, etc. Specifically, it can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, and 8 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein; the width of the second extension portions 422 can be 2 mm to 6 mm, 3 mm to 5 mm, 2 mm to 5 mm, or 4 mm to 4.5 mm, etc. Specifically, it can be 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. It can be understood that when the widths of the first extension portion 421 and the second extension portions 422 are within the above range, when they are bent inward, they can have a larger connection area to be connected to the first region 141 and the second region 142 respectively, improving the connection stability between the insulating film 4 and the connection region 14, and will not affect the electrical connection between the connecting piece 13 and the bare battery cell 2 during the subsequent assembly process due to excessive coverage of the top wall region of the bare battery cell 2; at the same time, the length of the battery cell is greater than the width of the battery cell, so that the connection strength between the first extension portion 421 and the first region 141 is greater than the connection strength between the second extension portions 422 and the second region 142, which can ensure the stable installation of the insulating film 4.

[0036] It should be noted that there is an overlapping part between the first region 141 and the second region 142. If the insulating film 4 is provided here, the insulating film 4 laminated on the overlapping part between the first region 141 and the second region 142 includes an upper part and a lower part. The lower part of the insulating film 4 is not easily welded to the connection region 14, affecting the connection effect between the insulating film 4 and the connection region 14. Therefore, in this application, the insulating film 4 is not provided at the overlapping part between the first region 141 and the second region 142 to ensure the connection stability between the insulating film and the first region 141 and the second region 142.

[0037] The insulating film 4 of the above-mentioned coating structure can be a single complete insulating film 4 that wraps the outside of the bare battery cell 2, that is, the film body 41 and the extension part 42 are of an integrally formed structure; it can also be a combination of multiple incomplete insulating films 4 that wrap the outside of the bare battery cell 2, that is, the film body 41 or the extension part 42 is composed of multiple film structures. It can be understood that when a part of the insulating film 4 with a split structure is damaged during the assembly process, it can be replaced without replacing the entire insulating film 4, reducing the assembly cost.

[0038] Preferably, the insulating film 4 of the present application is composed of two parts. Specifically: The insulating film 4 includes a first part 43 and a second part 44 with the same structure. Both the first part 43 and the second part 44 include a film body 41 and an extension part 42. Among them, both the first part 43 and the second part 44 include second extension parts 422 arranged opposite to each other along the length direction of the battery cell, and include a first extension part 421. The first part 43 and the second part 44 can enclose to form a rectangular box. The bare battery cell 2 includes a top wall, a bottom wall, a left side wall, a right side wall, a front side wall and a rear side wall; the top wall and the bottom wall are arranged opposite to each other along the height direction of the bare battery cell 2, the left side wall and the right side wall are arranged opposite to each other along the length direction of the bare battery cell 2, and the front side wall and the rear side wall are arranged opposite to each other along the width direction of the bare battery cell 2. The insulating film 4 covers the bottom wall, the left side wall, the right side wall, the front side wall, the rear side wall and a part of the top wall of the bare battery cell 2. Among them, the battery cell is divided along the center line of the battery cell. The first part 43 wraps the rear side wall, a part of the top wall, a part of the left side wall, a part of the right side wall and a part of the bottom wall of the bare battery cell 2; the second part 44 wraps the front side wall, a part of the top wall, another part of the left side wall, another part of the right side wall and another part of the bottom wall of the bare battery cell 2; and the film bodies 41 of a part of the first part 43 and the second part 44 overlap and are arranged on the top wall, the bottom wall, the left side wall and the right side wall of the bare battery cell 2.

[0039] It should be noted that a part of the left side wall, a part of the right side wall, a part of the bottom wall of the bare battery cell 2 and another part of the left side wall, another part of the right side wall and another part of the bottom wall constitute a complete bottom wall, left side wall and right side wall, and when the first part 43 and the second part 44 wrap the bottom wall, the left side wall and the right side wall, there are overlapping parts.

[0040] In some embodiments, the conventional top cover structure includes a positive upper plastic, a negative upper plastic, a lower plastic, an explosion-proof sheet, an explosion-proof valve patch, a sealing ring, a light aluminum sheet, a negative pole column, a positive pole column, an insulating sheet and a connecting sheet.

[0041] Among them, the lower plastic is the bottom component of the top cover structure, which plays the role of insulating part of the top cover structure and the bare battery cell. Specifically, the lower plastic uses insulating materials such as pp and contacts the housing to ensure insulation between the inside of the battery cell and the external circuit and prevent the battery cell from short-circuiting.

[0042] The lower plastic has an installation position for the terminal posts. The cylindrical positive terminal post and negative terminal post are installed on the lower plastic. The negative terminal post and the positive terminal post often use materials with good electrical conductivity. Exemplarily, the positive terminal post can use aluminum or aluminum alloy, and the negative terminal post can use copper or copper alloy, aluminum or aluminum alloy, etc. Their structures are the same. As the external interface of the battery cell, they connect the internal tabs of the battery cell with the external circuit.

[0043] The connecting piece is used to provide a reliable electrical connection, connecting the tabs of the bare battery cell with the bottoms of the positive and negative terminal posts of the battery pack. Usually, materials with good electrical conductivity such as copper and its alloys are used. While having a certain mechanical strength, it can ensure that the current can pass smoothly.

[0044] The upper positive plastic covers the top of the exposed bright aluminum sheet of the positive terminal post, playing the role of fixing the positive terminal post and conducting electricity. Specifically, the upper positive plastic uses conductive materials such as conductive PPS. The above-mentioned conductive materials enable the upper positive plastic to improve the electrical conductivity between the positive terminal post and the internal circuit of the battery, improving the output power and efficiency of the battery.

[0045] The upper negative plastic covers the top of the exposed bright aluminum sheet of the negative terminal post, playing the role of fixing the negative terminal post and insulating. Specifically, the upper negative plastic uses insulating materials such as insulating PPS. The above-mentioned insulating materials can prevent contact short - circuit between the negative terminal post and the housing or other metal parts, provide electrical isolation, improve the safety and stability of the battery cell, and avoid electrical failures caused by accidental contact.

[0046] The bright aluminum sheet is sleeved on the terminal post through welding (such as ultrasonic welding, laser welding or resistance welding) to form a reliable electrical connection, providing structural support for the positive terminal post and the negative terminal post; and the bright aluminum sheet has good heat conduction performance, which can help the battery cell dissipate heat and reduce the temperature of the battery pack.

[0047] The explosion - proof sheet and the explosion - proof valve patch are made of high - temperature - resistant materials. The bright aluminum sheet is provided with installation positions for both. The explosion - proof sheet and the explosion - proof valve patch are installed in the above - mentioned installation positions and are used in combination after being laminated to ensure that the internal pressure of the housing can be released in time when necessary, guaranteeing the safety of the charging and discharging process of the battery cell.

[0048] The sealing ring is sleeved on the outer periphery of the positive and negative terminal posts and is usually made of elastic materials such as fluororubber. These materials have good sealing performance and aging resistance, and have good sealing performance, which can ensure the isolation between the inside and the outside of the battery cell and prevent moisture from invading.

[0049] Different from the conventional top - cover structure, the top - cover structure 1 provided in this application specifically includes a sealing ring 15, a support component, a bright aluminum sheet 12, a negative terminal post, a positive terminal post, an insulating sheet 17 and a connecting piece 13.

[0050] Among them, the connecting piece 13 is used to provide a reliable electrical connection, connecting the tab of the bare battery cell 2 to the bottom of the positive and negative electrode posts 11 of the battery pack. Usually, materials with good electrical conductivity such as copper and its alloys are used. While having a certain mechanical strength, it can ensure that the current can pass smoothly.

[0051] The light aluminum sheet 12 is sleeved on the electrode post 11 through welding (such as ultrasonic welding, laser welding or resistance welding) to form a reliable electrical connection. Specifically, the light aluminum sheet 12 is provided with an installation hole 121. The positive electrode post and the negative electrode post pass through the installation hole 121 to provide structural support for the positive and negative electrode posts; and the light aluminum sheet 12 has good heat conduction performance, which can help the battery cell dissipate heat and reduce the temperature of the battery pack.

[0052] The connection area 14 of the top cover structure 1 is arranged on the insulating sheet 17. The insulating sheet 17 is made of materials with good insulation performance, such as PE, PP, etc. It is sleeved on the outer periphery of the electrode post 11 and is located between the light aluminum sheet 12 and the connecting piece 13, and is used to isolate the positive and negative electrodes to prevent short circuit.

[0053] The sealing ring 15 is annular, sleeved on the outer periphery of the positive and negative electrode posts 11, and the sealing ring 15 passes through the installation hole 121 of the light aluminum sheet 12 and abuts against the wall surface where the installation hole 121 is located, that is, the sealing ring 15 is located between the positive and negative electrode posts 11 and the wall surface of the installation hole 121. The sealing ring 15 is usually made of elastic materials such as fluororubber. These materials have good sealing performance and aging resistance, and have good sealing performance, which can ensure the isolation between the inside of the battery cell and the external environment and prevent moisture from invading.

[0054] It should be noted that at least part of the wall surface of the installation hole 121 used in this application is an inclined surface. Specifically, along the height direction of the electrode post 11, the cross-sectional shape of the upper part of the installation hole 121 is an inverted boss structure, and the cross-sectional shape of the lower part of the installation hole 121 is a boss structure. It can be understood that the cross-sectional shape of the above installation hole 121 is approximately "hourglass-shaped". When the sealing ring 15 is installed in the installation hole 121, under the guiding action of the inclined surface, the sealing ring 15 can be better deformed and filled in the installation hole 121 and closely attached, reducing the gaps between the sealing ring 15 and the wall surfaces of the installation hole 121 and the positive and negative electrode posts, and improving the sealing effect of the sealing ring 15.

[0055] Meanwhile, the support assembly includes a first pressing block 161 and a second pressing block 162; in the thickness direction of the sealing ring 15, the sealing ring 15 is disposed between the first pressing block 161 and the second pressing block 162. Understandably, in the height direction of the positive and negative electrode posts 11, the first pressing block 161 and the second pressing block 162 are respectively abutted against both sides of the sealing ring 15. By applying appropriate pressure, it is ensured that there is close contact between the sealing ring 15 and the electrode post 11 and the wall surface of the mounting hole 121, thereby achieving good sealing performance. During the actual assembly process, first, the sealing ring 15 is placed around the electrode post 11 and is located between the electrode post 11 and the mounting hole 121 of the light aluminum sheet 12. Then, the first pressing block 161 and the second pressing block 162 are used to fix it in place. At this time, the first pressing block 161 and the second pressing block 162 apply appropriate pressure to ensure that the sealing ring 15 deforms and fills the mounting hole 121 and fits tightly, thereby achieving good sealing performance. The first pressing block 161 and the second pressing block 162 used in this application are ceramic pressing blocks, and the second pressing block 162 serves as the lower part of the support assembly. Corresponding clamping structures can be set according to the structures of the sealing ring 15, the light aluminum sheet 12, the negative electrode post, the positive electrode post, the insulating sheet 17, and the connecting piece 13, making the assembly of the top cover assembly more stable. Exemplarily, a convex structure can be provided on the top of the second pressing block 162, and a clamping groove corresponding to the electrode post can be provided at the bottom of the second pressing block 162, which is not limited herein.

[0056] Understandably, the sealing ring 15, the support assembly, the light aluminum sheet 12, the negative electrode post, the positive electrode post, the insulating sheet 17, and the connecting piece 13 are assembled to form the top cover structure 1 of this application, jointly ensuring a reliable electrical connection between the battery cell and the external circuit and providing necessary structural support and protection.

[0057] In some embodiments, the electrode post 11 of this application includes a main body portion 111, a first bending portion 112, and a second bending portion 113. The main body portion 111 is a plate-like structure, and the length of the main body portion 111 is the length of the electrode post 11. The width of the plate-like structure is not limited in this application and can be selected according to the capacity of the battery cell.

[0058] As an alternative technical solution of the present application, the ratio of the length of the positive electrode terminal or the negative electrode terminal to the length of the battery cell is ≥10%. Optionally, the percentage range of the length of the positive electrode terminal or the negative electrode terminal to the length of the battery cell is 15% - 20%, 18 - 25% or 21% - 27%, etc. Specifically, it can be 10%, 15%, 20%, 25%, 30%, 35% and 40%, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. When the percentage of the length of the positive electrode terminal or the negative electrode terminal to the length of the battery cell in the present application is within the above range, the terminal 11 is of a larger size, has higher mechanical strength, has a lower contact resistance and a greater current-carrying capacity, and can meet the production requirements of large-capacity battery cells; moreover, the terminal 11 of a larger size has better heat dissipation performance, which can ensure that the battery cell operates within a safe temperature range. It can be understood that if the ratio of the length of the terminal 11 to the length of the battery cell is too small, that is, the size of the terminal 11 is small, it increases the difficulty of welding and connection. Poor welding may lead to poor contact, affecting the electrical performance and reliability of the battery, and the terminal 11 with too small a size has low mechanical strength, a higher contact resistance and a low current-carrying capacity; if the ratio of the length of the terminal 11 to the length of the battery cell is too large, it will increase the overall weight of the battery and increase the manufacturing cost of the battery. Preferably, the ratio of the length of the terminal 11 to the length of the battery cell is 10% - 30%.

[0059] As another alternative technical solution of the present application, the ratio of the total length of the positive electrode terminal and the negative electrode terminal to the length of the battery cell is ≥10%. Optionally, the percentage range of the total length of the positive electrode terminal and the negative electrode terminal to the length of the battery cell is 13% - 17%, 18 - 25% or 30% - 36%, etc. Specifically, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 55%, 60% and 65%, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. When the percentage of the total length of the positive electrode terminal and the negative electrode terminal to the length of the battery cell in the present application is within the above range, the terminal 11 is of a larger size, has higher mechanical strength, has a lower contact resistance and a greater current-carrying capacity, and can meet the production requirements of large-capacity battery cells; moreover, the terminal 11 of a larger size has better heat dissipation performance, which can ensure that the battery cell operates within a safe temperature range. It can be understood that if the ratio of the length of the terminal 11 to the length of the battery cell is too small, that is, the size of the terminal 11 is small, it increases the difficulty of welding and connection. Poor welding may lead to poor contact, affecting the electrical performance and reliability of the battery, and the terminal 11 with too small a size has low mechanical strength, a higher contact resistance and a low current-carrying capacity; if the ratio of the length of the terminal 11 to the length of the battery cell is too large, it will increase the overall weight of the battery and increase the manufacturing cost of the battery. Preferably, the ratio of the total length of the positive electrode terminal and the negative electrode terminal to the length of the battery cell is 10% - 30%.

[0060] Preferably, along the length direction of the battery cell, the length of the terminal 11 is 10 mm to 100 mm. Optionally, the length of the terminal 11 can be 18 mm to 25 mm, 36 mm to 44 mm, 27 mm to 65 mm, etc. Specifically, it can be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. It can be understood that when the length of the terminal 11 is within the above range, it has a certain mechanical strength, and at the same time, has a lower contact resistance and a greater current-carrying capacity; moreover, the terminal 11 with a larger size has a larger heat dissipation area, that is, better heat dissipation performance, which can ensure that the battery cell operates within a safe temperature range.

[0061] In some embodiments, along the height direction of the battery cell, the first bent portion 112 and the second bent portion 113 are respectively located on both sides of the mounting hole 121 of the light aluminum sheet 12 and horizontally extend along the width direction of the battery cell; along the width direction of the battery cell, the first bent portion 112 and the second bent portion 113 whose projections are located on the same straight line extend in opposite directions along the width direction of the battery cell, that is, the first bent portion 112, the main body portion 111, and the second bent portion 113 whose projections are located on the same straight line form a "Z" - shaped structure. At the same time, along the length direction of the battery cell, the adjacent first bent portions 112 bend in opposite directions along the width direction of the battery cell, and the adjacent second bent portions 113 bend in opposite directions along the width direction of the battery cell. It can be understood that for the terminal 11 with the above - mentioned structure, the first bent portion 112 and the second bent portion 113 are misaligned in the length direction, width direction, and height direction of the battery cell, which can better fix with the connecting piece 13 and the light aluminum sheet 12.

[0062] Along the length direction of the battery cell, the widths of the first bent portion 112 and the second bent portion 113 are 1 mm to 10 mm. Along the width direction of the battery cell, the extension lengths of the first bent portion 112 and the second bent portion 113 are 0.5 mm to 5 mm. Optionally, the widths of the first bent portion 112 and the second bent portion 113 can be 2 mm to 5 mm, 4 mm to 7 mm, 3 mm to 9 mm, etc. Specifically, they can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. The extension lengths of the first bent portion 112 and the second bent portion 113 can be 0.7 mm to 3 mm, 1 mm to 4 mm, 2.5 mm to 3.5 mm, etc. Specifically, they can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein.

[0063] Along the length direction of the battery cell, the spacing distance between adjacent first bending portions 112 and adjacent second bending portions 113 is 0.17 mm to 3.4 mm. Optionally, the spacing distance between adjacent first bending portions 112 and adjacent second bending portions 113 can be 0.18 mm to 0.95 mm, 1.6 mm to 2.7 mm, 1 mm to 3 mm, etc. Specifically, it can be 0.17 mm, 0.67 mm, 1.17 mm, 1.67 mm, 2.17 mm, 2.67 mm, 3.17 mm, 3.4 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein.

[0064] It can be understood that when the widths and extension lengths of the first bending portion 112 and the second bending portion 113 and the spacing distance between adjacent first bending portions 112 and adjacent second bending portions 113 are within the above ranges, and when the length of the pole column 11 is fixed, the number of the first extension portions 421 and the second extension portions 422 is ensured to enhance the connection stability between the second bending portion 113 and the connection piece 13 while reducing the contact resistance between the first bending portion 112 and the second bending portion 113.

[0065] In some embodiments, the connection piece 13 connected to the second extension portion 422 is used to connect the bare battery cell 2 inside the battery cell and the pole column 11. During the charge and discharge process of the battery cell, the connection piece 13 can carry the current during the charge and discharge process of the battery cell to ensure that the current can pass through stably, and further ensure that the electric energy generated inside the battery cell can be transmitted to the outside of the battery cell stably.

[0066] The connection piece 13 of the present application is a rectangular sheet-like structure, and a plurality of first connection holes 131 are arranged on its surface in a staggered manner. The distribution positions of the first connection holes 131 correspond to the shape of the second bending portion 113, so that the second bending portion 113 of the pole column 11 and the first connection holes 131 can be clamped during the assembly of the battery cell, and the second bending portion 113 does not protrude from the surface of the connection piece 13 away from the light aluminum sheet 12. It can be understood that the design that the second bending portion 113 does not protrude from the surface of the connection piece 13 can reduce the influence of the second bending portion 113 on the connection stability between the connection piece 13 and the bare battery cell 2, the connection between the connection piece 13 and the bare battery cell 2 is more stable, and the risk of loosening or falling off of the connection piece 13 and the bare battery cell 2 due to poor contact is reduced, ensuring good electrical connection of the battery cell in a vibration or impact environment and extending the service life of the battery cell.

[0067] At the same time, compared with the conventional adapter piece, for the connection piece 13 with a rectangular sheet-like structure, the welding positions 132 of the sheet-like connection piece 13 can be directly welded or connected to the pole ears of the bare battery cell 2, simplifying the connection process, eliminating the need for additional connectors or joints, and reducing the intermediate links during the installation of the connection piece 13; moreover, the connection distance between the pole ear and the connection piece 13 is shortened, further reducing the resistance loss during the current transmission process.

[0068] In some embodiments, the battery pack further includes a tab 5. The battery cell is connected to the external circuit through the tab 5, which plays a role in fixing the battery cell, ensuring a stable connection between the battery cell and other components during the encapsulation process, and also enabling the electrical energy generated inside the battery cell to be stably transmitted to the external circuit. During the charging and discharging process of the battery cell, the tab 5 can carry the current during the charging and discharging process of the battery cell to ensure that the current can pass stably.

[0069] The tab 5 of the present application has a rectangular sheet structure, similar to the structure of the connecting piece 13. A plurality of second connection holes 51 are arranged in a staggered manner on its surface. The distribution positions of the second connection holes 51 correspond to the shape of the first bent portion 112, so that when the battery cell is assembled, the first bent portion 112 of the pole 11 can be clamped with the second connection hole 51, and the first bent portion 112 does not protrude from the surface of the tab 5 away from the light aluminum sheet 12.

[0070] It can be understood that by adopting the above-mentioned clamping connection method for the connecting piece 13 and the second extension part 422, and the tab 5 and the first extension part 421 of the present application, the connection stability between the pole 11 and the connecting piece 13 and the tab 5 can be ensured.

[0071] Furthermore, after the first bent portion 112 is clamped with the second connection hole 51 of the tab 5 and the second bent portion 113 is clamped with the first connection hole 131 of the connecting piece 13, the edge where the first bent portion 112 abuts against the tab 5 can be welded, and the edge where the second bent portion 113 abuts against the connecting piece 13 can be welded, further improving the connection stability between the first bent portion 112 and the tab 5, and the second bent portion 113 and the connecting piece 13.

[0072] In some embodiments, the present application also provides a preparation process for a battery cell, including the assembly process of the top cover structure 1. The assembly process of the top cover structure 1 includes: Step S10, preparing the pole 11, the light aluminum sheet 12 and the connecting piece 13; wherein, the pole 11 includes a main body portion 111, a first extension part 421 and a second extension part 422. Along the height direction of the battery cell, the first extension part 421 and the second extension part 422 are respectively arranged at both ends of the main body portion 111; the light aluminum sheet 12 is provided with a mounting hole 121, and the connecting piece 13 is provided with connection holes arranged in a staggered manner; Step S20, the main body portion 111 of the terminal post 11 is inserted into the mounting hole 121 of the light aluminum sheet 12, and the first extension portion 421 is bent to form the first bent portion 112, and the second extension portion 422 is bent to form the second bent portion 113; wherein, the bending directions of the first bent portion 112 and the second bent portion 113 are opposite in the width direction of the battery cell; and along the length direction of the battery cell, the bending directions of adjacent first bent portions 112 are opposite in the width direction of the battery cell, and the bending directions of adjacent second bent portions 113 are opposite in the width direction of the battery cell; Step S30, the first connection hole 131 of the connection piece 13 is clamped with the second bent portion 113 of the terminal post 11, and the second bent portion 113 does not protrude from the surface of the connection piece 13 away from the light aluminum sheet 12.

[0073] In step S10, the first extension portion 421 and the second extension portion 422 are not bent, that is, the main body portion 111, the first extension portion 421 and the second extension portion 422 are located in the same plane, the terminal post 11 is a plate-like structure, the first extension portion 421 is spaced on one side of the main body portion 111 along the height direction, and the second extension portion 422 is spaced on the other side of the main body portion 111 along the height direction.

[0074] In step S20, the terminal post 11 is a plate-like structure, and at least part of the wall surface of the mounting hole 121 is an inclined surface. The terminal post 11 can pass through the mounting hole 121 of the light aluminum sheet 12, so that the light aluminum sheet 12 is sleeved on the outer periphery of the main body portion 111. At the same time, an annular insulating sealing ring 15 is provided between the outer wall surface of the main body portion 111 and the mounting hole 121. The sealing ring 15 abuts against the inclined surface where the mounting hole 121 is located, and along the height direction of the terminal post 11, a first pressing block 161 and a second pressing block 162 are respectively arranged on both sides of the sealing ring 15, that is, the sealing ring 15, the first pressing block 161 and the second pressing block 162 are sleeved on the outer periphery of the terminal post 11 and are stacked along the height direction of the terminal post 11. The first pressing block 161 and the second pressing block 162 apply appropriate pressure to ensure the close contact between the sealing ring 15, the terminal post 11 and the housing 3, so as to achieve good sealing performance of the sealing ring 15.; After the first pressing block 161 and the second pressing block 162 are installed, an acting force is applied to the first extension portion 421 and the second extension portion 422 to bend them to form the first bent portion 112 and the second bent portion 113. It can be understood that after the first bent portion 112 and the second bent portion 113 are formed, the first pressing block 161 and the second pressing block 162 can be further fixed to the sealing ring 15.

[0075] In step S30, the first connection hole 131 of the connecting piece 13 is snapped onto the second bent portion 113 of the pole 11. The specific process is as follows: The bent structure formed by the first connection holes 131 and the second bent portion 113 that are misaligned and distributed on the connecting piece 13 are aligned in spatial position and snapped together.

[0076] After step S30, there is also step S40: The edge of the second bent portion 113 of the pole 11 is welded to the edge of the first connection hole 131 of the connecting piece 13, and the edge of the first bent portion 112 of the pole 11 is welded to the edge of the second connection hole 51 of the bus bar 5. It can be understood that by using the welding method to fix the second bent portion 113 to the connecting piece 13 and the first bent portion 112 to the bus bar 5, the connection stability between the first bent portion 112 and the bus bar 5, and the second bent portion 113 and the connecting piece 13 can be further improved.

[0077] After step S30, an assembled component is obtained, and then the upper plastic for the positive electrode, the lower plastic for the negative electrode, the lower plastic, the explosion-proof sheet, the explosion-proof valve patch are connected to the assembled component to complete the assembly process of the top cover structure 1. It should be noted that the structures of components such as the upper plastic for the positive electrode and the lower plastic for the negative electrode can be adjusted according to the shape and size of the pole 11, and are not limited here.

[0078] After step S30, there is also the process of covering the insulating film 4. The process of covering the insulating film 4 specifically includes: Step S40, prepare the bare battery cell 2, the top cover structure 1 and the insulating film 4; the bare battery cell 2 includes a top wall, a bottom wall, a left side wall, a right side wall, a front side wall and a rear side wall; the lower plastic of the top cover structure 1 is provided with a connection area 14, and the distance between the connection area 14 and the center of the top cover structure 1 is less than the distance between the edge of the top cover structure 1 and the center of the top cover structure 1; the battery cell also includes the insulating film 4; the insulating film 4 includes a first part 43 and a second part 44 with the same structure. Both the first part 43 and the second part 44 are provided with a film main body 41 and an extension part 42.

[0079] Step S50, cover the bare battery cell 2 along the width direction of the bare battery cell 2 with the first part 43 and the second part 44. Among them, the film main body 41 of the first part 43 covers the rear side wall, part of the top wall, part of the left side wall, part of the right side wall and part of the bottom wall of the bare battery cell 2; the film main body 41 of the second part 44 covers the front side wall, part of the top wall, another part of the left side wall, another part of the right side wall and another part of the bottom wall of the bare battery cell 2; and the film main bodies 41 of part of the first part 43 and the second part 44 overlap on the bottom wall, the left side wall and the right side wall of the bare battery cell 2. In step S60, the extension parts 42 of the first part 43 and the second part 44 are bent towards the center of the top surface of the bare battery cell 2 along the length direction and the width direction of the bare battery cell 2, so that the extension parts 42 are located between the connection area 14 and the top surface of the bare battery cell 2, and the upper surfaces of the extension parts 42 are connected to the connection area 14.

[0080] After step S60, the connection process of the insulating film 4 and the connection area 14 is further included: the extension parts 42 and the connection area 14 of the top cover structure 1 are connected by hot melting, and then the top cover structure 1 and the housing 3 are welded. At this time, the insulating film 4 will not be squeezed into the welding gap between the housing 3 and the top cover structure 1, which can avoid the insulating film 4 interfering with the welding between the top cover structure 1 and the housing 3, reduce the situation of poor welding, ensure the sealing performance and electrical connection effect of the battery pack, and further improve the working performance and safety of the battery pack.

[0081] Through the above steps S40 to S60, the bare battery cell 2 and the top cover structure 1 can be connected. After the bottom of the bare battery cell 2 is connected to the bottom support piece 21, the bare battery cell 2 is assembled into the housing 3, and the housing 3 and the top cover are welded to complete the assembly process of the battery cell.

[0082] The structure, features and effects of the present invention have been described in detail based on the embodiments shown in the drawings. The above are only the preferred embodiments of the present invention, but the present invention is not limited to the scope shown in the drawings. Any changes made according to the concept of the present invention, or modified into equivalent embodiments with equivalent changes, still within the spirit covered by the specification and the drawings, shall be within the protection scope of the present invention.

Claims

1. A battery cell, comprising a top cover structure, characterized in that: The top cover structure comprises: A pole, comprising a main body, a first bending portion and a second bending portion; wherein, along the height direction of the battery cell, the first bending portion and the second bending portion are respectively arranged on both sides of the main body, and extend horizontally along the width direction of the battery cell; along the width direction of the battery cell, the first bending portion and the second bending portion projected on the same straight line extend in opposite directions in the width direction of the battery cell; along the length direction of the battery cell, the adjacent first bending portions have opposite bending directions in the width direction of the battery cell, and the adjacent second bending portions have opposite bending directions in the width direction of the battery cell; The bare aluminum sheet is provided with a mounting hole, the main body of the pole is inserted into the mounting hole, and along the height direction of the battery core, the first bending portion and the second bending portion are respectively located on both sides of the mounting hole.

2. The battery cell according to claim 1, characterized in that: Along the length direction of the battery core, the length of the pole is 10 mm to 100 mm; and / or, The length of the pole accounts for ≥10% of the length of the battery cell.

3. The battery cell according to claim 1, characterized in that: Along the length direction of the battery core, the width of the first bending portion and the second bending portion is 1 mm to 10 mm; and / or, The extension length of the first bending portion and the second bending portion is 0.5 mm to 5 mm.

4. The battery cell according to claim 1, characterized in that: Along the length direction of the battery core, the spacing distance between adjacent first bending portions is 0.17 mm to 3.4 mm, and the spacing distance between adjacent second bending portions is 0.17 mm to 3.4 mm.

5. The battery cell according to claim 1, characterized in that: The top cover structure also includes a connecting plate, which is provided with first connecting holes that are staggered, the second bent portion of the pole is engaged with the first connecting hole, and the second bent portion does not protrude from the surface of the connecting plate away from the bare aluminum sheet.

6. The battery cell according to claim 5, characterized in that: The connecting piece is clamped and then welded to the second bent portion.

7. A process for preparing a battery cell, including an assembly process of a top cover structure, characterized in that: The assembly process of the top cover structure includes: Prepare a pole and a bare aluminum sheet, wherein the pole includes a main body, a first extension portion and a second extension portion, along the height direction of the battery cell, the first extension portion and the second extension portion are respectively arranged at two ends of the main body, and the bare aluminum sheet is provided with a mounting hole; The main body of the pole is inserted into the mounting hole of the bare aluminum sheet, and the first extending portion is bent to form a first bending portion, and the second extending portion is bent to form a second bending portion; wherein the first bending portion and the second bending portion have opposite bending directions in the width direction of the battery cell; and along the length direction of the battery cell, the adjacent first bending portions have opposite bending directions in the width direction of the battery cell, and the adjacent second bending portions have opposite bending directions in the width direction of the battery cell.

8. The process for preparing the battery cell according to claim 7, characterized in that: The assembly process of the top cover structure also includes: Providing a sealing ring, sleeved on the outer circumference of the pole, and making the sealing ring located between the pole and the wall surface of the mounting hole; Providing an insulating sheet, and sleeved the insulating sheet on the outer periphery of the pole, the insulating sheet being located on a side of the bare aluminum sheet facing the second bent portion; A connecting plate is provided, wherein the connecting plate is provided with a plurality of first connecting holes which are staggered and distributed, and the first connecting holes of the connecting plate are clamped with the second bent portion of the pole, and the second bent portion is prevented from protruding from the surface of the connecting plate away from the bare aluminum sheet.

9. An energy storage device, characterized in that: The energy storage device includes a battery management system, an energy storage inverter, an energy management system and a battery pack, and the battery pack includes a plurality of battery cells as described in any one of claims 1 to 6 or battery cells prepared by the preparation process of the battery cells as described in any one of claims 7 to 8.

10. The energy storage device according to claim 9, characterized in that: The battery pack also includes a tab, the battery cell is connected to the external circuit via the tab, the tab is provided with a plurality of second connection holes that are staggered, the first bent portion of the pole of the battery cell is engaged with the second connection hole, and the first bent portion does not protrude from the surface of the tab away from the bare aluminum sheet.

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