A high-energy high-safety lithium battery

Abstract

The utility model discloses a high energy high safety performance's lithium cell, including electric core and its outside setting casing, and the casing includes upper shell and its sealed connection lower shell, and the lower shell is the rectangular casing of one side opening, is equipped with the recess for installing circuit board, the first through -hole for installing the sealing nail after pouring liquid and the second through -hole for installing pole post subassembly on the upper end surface of lower shell, and the second through -hole is still used for exporting the polarity of electrode, the head area of lower shell and the head area of upper shell jointly formed casing head area form the insulating barrier of electric core and lower shell contact surface, and the head area of lower shell is used for accommodating the first tab and second tab of electric core. A high energy high safety performance's lithium cell, sets up the structure of upper end surface and recess, makes electric core can be loaded into the casing, also can not cause the space waste, and the head area of casing can store more free electrolyte, is favorable to the long cycle life of battery.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, specifically to a high-energy, high-safety lithium battery. Background Technology

[0002] In current battery structures, the tabs of the battery cell need to be electrically led out through an adapter to form electrodes. Conventional designs place the adapter between the casing and the tabs along the battery's length, and finally mount the circuit board on the outside of the regular casing, leading to the following drawbacks: 1. Space occupation: The adapter and connecting structure occupy too much volume, forcing a reduction in cell size and significantly lowering the battery's volumetric energy density; however, this resulting size is difficult to further reduce. 2. Insulation safety risks: During the process of connecting the tabs to the casing (as electrodes) through the adapter, accidental contact with the casing can easily occur due to assembly tolerances, vibration, or electrolyte corrosion, causing internal short circuits. 3. The circuit board occupies additional space, compressing the internal volume of the casing, further reducing cell size and lowering the battery's volumetric energy density. Therefore, there is an urgent need for a new type of lithium-ion battery that optimizes space layout while improving insulation reliability. Utility Model Content

[0003] This utility model addresses at least one of the aforementioned problems in the prior art by disclosing a high-energy, high-safety lithium battery. The first and second through holes of this utility model are both located on the upper surface, eliminating the rigid size requirements of the groove. The groove only requires external mounting of a circuit board, allowing for more flexible adjustment of the overall structure of the lower casing, thereby improving casing utilization and ultimately increasing the battery's energy density.

[0004] This utility model is achieved through the following technical solution:

[0005] This utility model first provides a high-energy, high-safety lithium battery, including a battery cell and an external housing. The housing includes an upper shell and a sealed lower shell. The lower shell is a rectangular shell with an opening on one side. The upper surface of the lower shell has a groove for mounting a circuit board, a first through hole for mounting a sealing pin after liquid filling, and a second through hole for mounting an electrode assembly. The second through hole is also used to guide one polarity of the electrode. The head region of the lower shell and the head region of the upper shell together form an insulating barrier between the battery cell and the contact surface of the lower shell. The head region of the lower shell is used to accommodate the first and second tabs of the battery cell.

[0006] As a further improvement, the inner walls of the upper shell and the inner walls of the upper end face of the lower shell are coated with an insulating layer, which forms the head area of ​​the lower shell. The upper shell has a rectangular plate structure, and the part of the upper shell corresponding to the head area of ​​the lower shell is the head area of ​​the upper shell. The head area of ​​the upper shell is coated with an insulating layer, which is made of ceramic or PP.

[0007] As a further improvement, the cross-section of the groove is a right-angled trapezoidal structure, and the right angle of the groove coincides with a right angle of the upper end face. The upper end face includes a first upper end face and a second upper end face with an integral structure. Both the first upper end face and the second upper end face are rectangular surfaces, and the length of the first upper end face is the same as the length of the bottom of the groove.

[0008] As a further improvement, both the first through hole and the second through hole are located on the second upper end face, and are equidistant from the two long sides of the second upper end face.

[0009] As a further improvement, the first through hole is located on the first upper end face and is completely covered by the projection of the groove on the first upper end face. At the same time, the distance between the first through hole and the two long sides of the first upper end face is equal and ≥D / 2+0.4mm, where D is the inner diameter of the first through hole.

[0010] As a further improvement, both the upper surface and the groove are rectangular, and the width of both is equal to the width of the shell.

[0011] As a further improvement, the second through hole is a rectangular hole with a height of A1 and a width of B1, where A1*B1≥Smin; where Smin is the minimum value of the current-carrying area, Smin=I / J, where I is the battery current I, and J is the maximum current density; the distance between the second through hole and the edge of the upper end face is equal and ≥0.8mm; the center distance between the first through hole and the second through hole is ≥B1 / 2+D / 2+0.4mm, where D is the inner diameter of the first through hole.

[0012] As a further improvement, the battery cell also includes several stacked electrode sheets. Each electrode sheet is a rectangular sheet with a tab extending from one side. The electrode sheet has an upper rounded corner on the side near the tab and two lower rounded corners on the side away from the tab. The radius of the upper rounded corner is greater than or equal to the radius of the lower rounded corner.

[0013] As a further improvement, a U-shaped groove is provided below the electrode tab, forming a battery cell with a U-shaped groove on top.

[0014] As a further improvement, the electrode sheet has two structures: one is a rectangular sheet with an extended tab on one side, and the other is a rectangular sheet with a U-shaped groove on one side of the tab. The two structures of electrode sheets are stacked to form a battery cell with a rectangular part and a rectangular structure with a U-shaped groove, so that the electrode corresponding to the groove is the first electrode, the electrode corresponding to the upper end face is the second electrode, the first tab of the first electrode is connected to the electrode post assembly, the second tab of the first electrode is connected to the upper end face, the first tab of the second electrode is connected to the electrode post assembly, and the second tab of the second electrode is connected to the second side of the groove.

[0015] The features and beneficial effects of this utility model are as follows:

[0016] (1) The structure of the upper end face and groove of the shell of this utility model can ensure the strength of the shell structure and meet the amount of base material used when welding with the upper shell, so that the battery cell can be installed in the shell without causing space waste. At the same time, the head area of ​​the shell can store more free electrolyte, which is beneficial to the long cycle life of the battery.

[0017] (2) The first through hole and the second through hole of this utility model are both set on the upper end surface, so that the groove does not have the above-mentioned rigid problem of size requirements. The groove only needs to be externally installed with a circuit board, which makes the overall structure of the lower shell more flexible to be adjusted, thereby matching the structure of the cell, with higher utilization rate, and thus improving the energy density of the battery. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the battery described in an embodiment of the present utility model;

[0020] Figure 2 This is a schematic diagram of the first embodiment of the housing described in this utility model;

[0021] Figure 3 for Figure 2 Enlarged view of section A;

[0022] Figure 4 for Figure 2 Top view;

[0023] Figure 5 This is a schematic diagram of the upper shell according to an embodiment of the present utility model;

[0024] Figure 6 This is a schematic diagram of the first embodiment of the electrode sheet described in this utility model;

[0025] Figure 7 This is a schematic diagram of the first embodiment of the battery cell described in this utility model;

[0026] Figure 8 This is a side view of the first embodiment of the battery cell described in this utility model.

[0027] Figure 9 for Figure 8 BB-direction sectional view;

[0028] Figure 10 This is a schematic diagram of a second embodiment of the electrode sheet described in this utility model.

[0029] Figure 11 This is a schematic diagram of a second embodiment of the battery cell described in this utility model.

[0030] Figure 12 This is a schematic diagram of a third embodiment of the battery cell described in this utility model.

[0031] Figure 13 This is a schematic diagram of a second embodiment of the housing described in this utility model;

[0032] Figure 14 for Figure 13 Top view;

[0033] Figure 15 This is a schematic diagram of a third embodiment of the housing described in this utility model;

[0034] Figure 16 This is a schematic diagram of another embodiment of the battery described in this utility model.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1-Lower shell; 11-Upper end face; 111-First upper end face; 112-Second upper end face; 12-Groove; 121-First connecting part; 122-First surface of groove; 123-Second surface of groove; 13-First through hole; 14-Second through hole; 2-Upper shell; 3-Battery cell; 31-First electrode tab; 32-Second electrode tab; 33-Electrode body; 331-First electrode body; 332-Second electrode body; 34-Electrode sheet; 341-Upper rounded corner of electrode sheet; 342-Lower rounded corner of electrode sheet; 343-U-shaped groove; 4-Circuit board; 5-Electrode post assembly; 6-Sealing nail. Detailed Implementation

[0037] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be provided below, along with embodiments of this utility model, but this does not limit the scope of this utility model.

[0038] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] A high-energy, high-safety lithium battery, such as Figures 1 to 16 As shown, the device includes a battery cell 3 and an external housing. The housing includes an upper shell 2 and a lower shell 1 sealed to it. The lower shell 1 is a rectangular shell structure with an opening on one side. The upper end face 11 of the lower shell 1 is provided with a groove 12 for mounting a circuit board, a first through hole 13 for injecting liquid, and a second through hole 14 for mounting an electrode assembly. The second through hole is also used to guide one polarity of the electrode. The head region of the lower shell 1 and the head region of the upper shell 2 together form an insulating barrier between the battery cell 3 and the contact surface of the lower shell 1. The head region of the lower shell 1 is used to accommodate the first tab 31 and the second tab 32 of the battery cell 3.

[0041] The inner walls of the upper shell 1 and the upper end face 11 of the lower shell are coated with an insulating layer, forming the lower shell head region. The upper shell 2 is a rectangular plate structure, and the portion of the upper shell 2 corresponding to the lower shell head region is the upper shell head region. The interior of the upper shell head region is coated with an insulating layer. After welding, the upper shell 2 and the lower shell 1 form a sealed structure. The shell head region, composed of the lower shell head region and the upper shell head region, forms an insulating barrier between the contact surface of the battery cell 3 and the lower shell 1. The first and second electrodes of the battery cell have opposite polarities and therefore cannot contact the shell simultaneously. Therefore, insulation is required in the space from the electrode extension to the welding connection with the shell to prevent short circuits and safety issues. Conventional batteries achieve this by wrapping insulating glue on both sides of the electrodes. However, the adhesion of the insulating glue to the electrodes decreases significantly after soaking in electrolyte, leading to a risk of detachment over long-term use. This patent achieves insulation between the electrodes and the shell by coating an insulating layer on the shell, solving the short circuit problem, reducing operational difficulty, and improving production efficiency. The lower shell head area is used to accommodate the first tab 31 and the second tab 32, thereby reducing the head space occupied by the bending and welding of the battery head tabs. Therefore, this patent can reduce the space waste of the battery and improve the battery energy density.

[0042] The insulating layer is made of ceramic, PP, or other materials, with a thickness ranging from 20 to 200 μm. This solution involves spraying an insulating ceramic layer. This insulating ceramic layer has a double-layer structure: the bottom layer is dense Al2O3, which prevents electrical breakdown; the top layer is porous Al2O3, applied via plasma spraying; and the sol-gel method further enhances electrolyte wettability. The bottom insulating ceramic layer has a thickness of 5-10 μm, and the top insulating ceramic layer has a thickness of 15-40 μm. In some embodiments, the total thickness of the insulating ceramic layer ranges from 5-100 μm. A thickness below 5 μm may cause microcracks due to assembly stress, while a thickness exceeding 80 μm makes it prone to peeling.

[0043] In some embodiments, the upper end face 11 and the groove 12 are connected by rounded corners to avoid stress concentration and reduce the difficulty of processing.

[0044] like Figure 4 As shown, the inner diameter of the first through hole 13 is D, where 1.0mm≤D≤1.8mm. If D is too small, the gas inside the shell will be difficult to expel during the injection of electrolyte by the injection needle, which will easily cause electrolyte to overflow and contaminate the shell. At the same time, it will significantly reduce production efficiency. If D is too large, the distance between the first through hole and the edge of the lower shell will be too small, and the structural strength of the lower shell in the second direction will be reduced, which is not conducive to welding the sealing nail.

[0045] The second through-hole 14 is a rectangular hole with a height of A1 and a width of B1, and a current-carrying area of ​​S (i.e., the effective cross-sectional area through which current flows), where S = A1 * B1. If this area is too small, it will lead to Joule heating and poor contact, which is detrimental to the battery's safety performance. At the same time, a small contact area between the electrode and the same terminal assembly on the circuit board will lead to poor voltage contact, further resulting in low battery voltage. Moreover, the current-carrying area S affects the battery's internal resistance. To ensure a sufficient current-carrying area, S should have a minimum design value Smin based on the battery design and charge / discharge conditions, i.e., A1 * B1 ≥ Smin. Here, Smin is calculated based on the battery current I, the maximum current density J, and the properties of the positive and negative electrode materials using Smin = I / J.

[0046] In the second direction, the distance between the second through hole 14 and the two edges of the upper end face 11 is equal, and they are denoted as A2 and A3, where A2 = A3 ≥ 0.8 mm. This ensures that after the second through hole is opened, the upper end face 11 can guarantee the structural strength of the shell and meet the substrate usage requirements when welding with the upper shell 2. In the first direction, the distance between the second through hole 14 and one edge of the upper end face 11 is denoted as B2, where B2 ≥ 0.8 mm. The edges of the lower shell are all rounded, and the rounded corners are ≥ 0.5 mm. The second through hole should be a certain distance from the rounded corners to facilitate the installation of the pole post assembly and to leave space for the welding of the pole lugs. The center distance between the first through hole 13 and the second through hole 14 is ≥ B1 / 2 + D / 2 + 0.4 mm to ensure the connection strength of the material between the two through holes.

[0047] In some embodiments, the second through hole may also be circular, or other shapes, or a combination of multiple shapes. The fundamental principle of its design is to ensure that the electrode tab is firmly welded to the housing, and to ensure that the current-carrying area is sufficient during charging and discharging.

[0048] The battery cell 3 includes an electrode body 33 and a first tab 31 and a second tab 32 extending from one side. The first tab 31 is electrically connected to the terminal post assembly 5, and the second tab 32 is electrically connected to the casing. Specifically, the first tab 31 of the battery cell is gathered to one side and welded to the terminal post assembly 5. The second tab 32 of the battery cell is gathered to one side and welded to the casing. Then, the battery cell is placed in the lower casing 1 and welded to the upper casing 1. Electrolyte is injected, and the through hole is sealed by welding with sealing nails 6 to form a battery.

[0049] Circuit board 4 is mounted in recess 12 and is positioned by recess 12, improving assembly accuracy and reducing assembly difficulty. Preferably, the dimensions are equal; this arrangement allows the battery to be a regular rectangle, facilitating the design and assembly of the battery compartment. The length, width, and height of circuit board 4 are all less than or equal to the length, width, and height of recess 12. To maximize space saving, preferably, the length, width, and height of circuit board 4 are all equal to the length, width, and height of recess 12.

[0050] To maximize the space utilization within the casing, the electrode body 31 is slightly smaller than the casing in all directions. This allows the battery cell 3 to fit into the casing without wasting space. Furthermore, this design allows for the storage of more free electrolyte in the casing's head region, contributing to a longer battery cycle life. In some embodiments, the dimensions of the electrode body in all directions are equal to the internal dimensions of the casing to achieve maximum energy density.

[0051] like Figure 7 Based on the cell structure diagram, the width C2 of the first tab 31 is greater than or equal to the width of the terminal assembly 5 to maintain the largest possible welding area, thereby ensuring a large current-carrying area and reducing the risk of battery thermal failure due to Joule heat accumulation at this location during power-on. The width C2 of the first tab 31 is as consistent as possible with the width C4 of the second tab, i.e., C2 = C4. The distance between the first tab and the second tab is greater than or equal to 2mm. This setting helps to accommodate errors during the assembly process and also prevents the two tabs from short-circuiting under bending or shaking conditions. The distance C1 between the first tab and the edge of the cell is greater than or equal to 0.3mm. This is because under the current manufacturing process, the minimum radius of the casing edge can be 0.3mm. If the manufacturing process is improved in the future, it can be made even smaller, which is also within the scope of patent protection.

[0052] like Figure 9 and Figure 4 From the cross-sectional view, the bending height of the tab is E1 ≥ A1 + A3 + 0.2 mm, E3 ≥ ▲h + 0.2 mm, and E2 ≥ A1 + 0.2 mm. E3 is the total thickness of the tab after bending, which is the height of the tab exceeding the electrode body 33. If this height is too small, the outer tab is prone to cracking under tensile force during the bending process after welding with the terminal assembly or shell, leading to partial electrode body failure and low battery capacity. If this height is too large, too many tabs will redundantly accumulate in the protrusion cavity after bending, making it difficult for the tabs to provide positioning for the electrode body in the first direction after welding. The electrode body and shell are prone to shaking, and the redundant tabs will also occupy too much space. The effective welding height E2 after the tab is bent is greater than the height of the terminal assembly to ensure welding area and current flow area. At the same time, the total height E1 after the tab is bent is less than the total height of the upper end face 11 to ensure that the tab can be accommodated in the protrusion cavity after bending. Also, E1 = E2 + total thickness of the tab.

[0053] like Figure 7The electrode 34, which makes up the battery cell 3, is formed by stacking multiple electrodes of different polarities alternately with a separator and then hot-pressing them. The electrode 34 is obtained by metal mold or laser die-cutting and has upper and lower rounded corners. The two rounded corners on the side closer to the tab are defined as the upper rounded corners 341, and the two rounded corners on the side farther from the tab are defined as the lower rounded corners 342. To match the manufacturing dimensions of the lower casing rounded corners while taking into account the battery energy density and maximizing the filling amount of active material, the radius of the upper rounded corner 341 is greater than or equal to the radius of the lower rounded corner 342.

[0054] like Figure 6 As shown, in some embodiments, the electrode 34 is a rectangular sheet with an extended tab on one side, and the formed electrode body 33 is a rectangular electrode body.

[0055] like Figure 10 and Figure 11 As shown, in some other embodiments, the electrode 34 is a rectangular piece with an extended tab on one side, and a U-shaped groove 343 is provided on the inner side below the tab, forming an electrode body with a U-shaped groove on top. With this configuration, the electrode body can fit the shape of the inner cavity of the housing, making the electrode on the side with the U-shaped groove longer in the second direction, allowing more electrodes to be accommodated in the housing and improving the volumetric energy density of the battery.

[0056] like Figure 12 As shown, in some other embodiments, the electrode 34 has two structures. One structure is a rectangular sheet with an extended tab on one side, and the other structure is a rectangular sheet with a U-shaped groove on one side of the tab. The two structures of the electrode are stacked to form an electrode body with a rectangular part and a rectangular structure with a U-shaped groove.

[0057] The connection method is as follows: the electrode corresponding to the groove 12 is the first electrode, and the electrode corresponding to the upper end face is the second electrode. The first tab of the first electrode is connected to the electrode post assembly 5, the second tab of the first electrode is connected to the upper end face, the first tab of the second electrode is connected to the electrode post assembly 5, and the second tab of the second electrode is connected to the second surface of the groove 12. Preferably, the first tabs of the first electrode and the first tabs of the second electrode can be welded together before being connected to the electrode post assembly to improve production efficiency and reduce assembly difficulty. Preferably, the second tab of the second electrode can be first gathered to one side of the first electrode, welded together with the second tab of the first electrode, and then welded together with the second protrusion to improve production efficiency and reduce assembly difficulty. In addition, to ensure that there is no relative movement between the first electrode and the second electrode, the connection method can be by hot pressing, applying double-sided tape, hot melt adhesive, or coating with connecting adhesive, etc.

[0058] like Figure 2As shown, in some embodiments, the upper end face 11 is a rectangular structure, the groove 12 is used to install the circuit board, the cross-section of the groove 12 is a right trapezoidal structure, and the right angle of the groove 12 coincides with a right angle of the upper end face 11. The upper end face 11 is divided into a first upper end face 111 and a second upper end face 112, wherein the first upper end face 111 is a rectangular surface and its length is the same as the length of the bottom of the groove 12.

[0059] To facilitate the description of the dimensional characteristics of the groove 12, it is described here as a right trapezoid: the lower base w ≥ 10mm, the height h ≥ 2mm, to accommodate the circuit board size; the groove depth Δh ≥ 0.8mm, to accommodate the circuit board thickness; the values ​​of w, h, and Δh represent the minimum reasonable size of the circuit board that can be achieved by existing processes, and the length, width, and height can be adjusted according to the specific circuit board size during actual implementation; the base angle is α, and it satisfies 5° ≤ α ≤ 60°. If α is too small, on the one hand, the groove depth of the groove 12 will be too small, and it will not provide enough space to install the circuit board; on the other hand, it will cause the width of the inclined surface (first connecting part 121) where the trapezoidal waist of the groove 12 is located to be too large. Since the circuit board is generally rectangular, after the circuit board is installed in the groove 12, the space between it and the first connecting part 121 will be too large and cannot be utilized, wasting the internal volume of the casing and further reducing the cell capacity. If α is too large, the slope of the first connecting part 121 will be too large. During the shell stretching process, the rounded corner connecting the upper end face 11 and the groove 12 is prone to corner accumulation or wrinkling, resulting in poor shell wall thickness consistency and easy breakage when subjected to external force.

[0060] The right angle of the groove 12 coincides with a right angle of the upper end face 11. Therefore, the groove 12 consists of three groove walls, namely the first connecting part 121, the first groove surface 122, and the second groove surface 123. The radius of the fillet between the first groove surface 122 and the first connecting part 121 is 1.2-3.5mm, the radius of the fillet between the first connecting part 121 and the large surface of the lower shell 2 is 1.2-3.5mm, the radius of the fillet between the first groove surface 122, the first connecting part 121, and the upper end face 11 is 0.5-3.5mm, and the radius of the fillet between the first groove surface 122 and the second groove surface 123 is 0.5-3.5mm. The minimum value depends on the current manufacturing capability. If R is too large, too much cavity space will be lost.

[0061] The upper surface 11 has a rectangular structure. The first through hole 13 and the second through hole 14 are both located on the second upper surface 112 and are equidistant from the two long sides of the second upper surface 112.

[0062] like Figure 13As shown, in some embodiments, the projection of the upper end face 11 in the vertical direction is rectangular, the cross-section of the groove 12 is a right-angled trapezoidal structure, and the right angle of the groove 12 coincides with one right angle of the upper end face 11. The upper end face 11 is divided into a first upper end face 111 and a second upper end face 112, wherein the first upper end face 111 is a rectangular surface and its length is the same as the length of the lower base of the groove 12. In order to reduce the space occupied by the relative position of the circuit board and the housing, the groove 12 is used to install the circuit board. In order to maximize the accommodation of the circuit board, if the width of the circuit board 4 is large, in order to ensure structural strength, the first through hole 13 is located on the first upper end face 111 and is completely covered by the projection of the groove 12 on the first upper end face 111. At the same time, the distance of the first through hole 13 from the two long sides of the first upper end face 111 is equal and ≥D / 2+0.4mm. With this arrangement, the structure is not easily deformed during subsequent liquid injection and welding of sealing nails. This size does not affect the shape stability of the housing and the welding yield.

[0063] To facilitate the description of the dimensional characteristics of the groove 12, it is described here as a right trapezoid: the lower base w ≥ 10mm, the height h ≥ 2mm, to accommodate the circuit board size; the groove depth Δh ≥ 0.8mm, to accommodate the circuit board thickness; the values ​​of w, h, and Δh represent the minimum reasonable size of the circuit board that can be achieved by existing processes, and the length, width, and height can be adjusted according to the specific circuit board size during actual implementation; the base angle is α, and it satisfies 5° ≤ α ≤ 60°. If α is too small, on the one hand, the groove depth of the groove 12 will be too small, and it will not provide enough space to install the circuit board; on the other hand, it will cause the width of the inclined surface (first connecting part 121) where the trapezoidal waist of the groove 12 is located to be too large. Since the circuit board is generally rectangular, after the circuit board is installed in the groove 12, the space between it and the first connecting part 121 will be too large and cannot be utilized, wasting the internal volume of the casing and further reducing the cell capacity. If α is too large, the slope of the first connecting part 121 will be too large. During the shell stretching process, the rounded corner connecting the upper end face 11 and the groove 12 is prone to corner accumulation or wrinkling, resulting in poor shell wall thickness consistency and easy breakage when subjected to external force.

[0064] The right angle of the groove 12 coincides with a right angle of the upper end face 11. Therefore, the groove 12 consists of three groove walls, namely the first connecting part 121, the first groove surface 122, and the second groove surface 123. The radius of the fillet between the first groove surface 122 and the first connecting part 121 is 1.2-3.5mm, the radius of the fillet between the first connecting part 121 and the large surface of the lower shell 2 is 1.2-3.5mm, the radius of the fillet between the first groove surface 122, the first connecting part 121, and the upper end face 11 is 0.5-3.5mm, and the radius of the fillet between the first groove surface 122 and the second groove surface 123 is 0.5-3.5mm. The minimum value depends on the current manufacturing capability. If R is too large, too much cavity space will be lost.

[0065] like Figure 15 As shown, in some other embodiments, the upper surface 11 and the groove 12 are both rectangular, and their widths are equal, both equal to the width of the housing. The width of the groove 12 is ≥10mm and the length is ≥2mm to accommodate the circuit board size. The groove depth of the groove 12 is ≥0.8mm to accommodate the circuit board thickness. The length, width and height of the groove are the minimum reasonable size of the circuit board that can be achieved by existing processes. In actual implementation, the length, width and height can be adjusted according to the specific circuit board size.

[0066] In the prior art, the groove 12 has a first through hole and a second through hole for mounting a circuit board. To ensure the dimensions of the first and second through holes are suitable for liquid injection and electrode assembly mounting, and also to guarantee the strength of the groove 12, the dimensions of the side of the groove 12 with the electrode and injection hole are relatively large, resulting in a larger groove 12, which increases the battery volume and limits the improvement of energy density. In this embodiment, however, both the first and second through holes are located on the upper end face 11, allowing for a smaller groove size. This allows the casing to accommodate more electrode bodies, thereby improving the battery's energy density. The groove does not have the aforementioned rigid size requirements; it only needs an external circuit board mounting surface. This allows for more flexible adjustment of the overall structure of the lower casing 1, enabling better matching with the battery cell structure and higher utilization.

[0067] It should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-energy, high-safety lithium battery, characterized in that: The device includes a battery cell and its external housing. The housing includes an upper housing and a sealed lower housing. The lower housing is a rectangular housing with an opening on one side. The upper surface of the lower housing has a groove for mounting a circuit board, a first through hole for mounting a sealing pin after liquid injection, and a second through hole for mounting an electrode assembly. The second through hole is also used to guide one polarity of the electrode. The head region of the housing, which is formed by the head region of the lower housing and the head region of the upper housing, forms an insulating barrier between the battery cell and the contact surface of the lower housing. The head region of the lower housing is used to accommodate the first and second tabs of the battery cell.

2. The high-energy, high-safety lithium battery according to claim 1, characterized in that: The inner walls of the upper shell and the inner walls of the upper end face of the lower shell are coated with an insulating layer, which forms the head area of ​​the lower shell. The upper shell is a rectangular plate structure. The part of the upper shell corresponding to the head area of ​​the lower shell is the head area of ​​the upper shell. The head area of ​​the upper shell is coated with an insulating layer. The insulating layer is made of ceramic or PP.

3. The high-energy, high-safety lithium battery according to claim 1, characterized in that: The groove has a right-angled trapezoidal cross-section, and the right angle of the groove coincides with a right angle of the upper end face. The upper end face includes a first upper end face and a second upper end face with an integral structure. Both the first upper end face and the second upper end face are rectangular surfaces, and the length of the first upper end face is the same as the length of the bottom of the groove.

4. A high-energy, high-safety lithium battery according to claim 1, characterized in that: Both the first through hole and the second through hole are located on the second upper end face, and are equidistant from the two long sides of the second upper end face.

5. A high-energy, high-safety lithium battery according to claim 1, characterized in that: The first through hole is located on the first upper end face and is completely covered by the projection of the groove on the first upper end face. At the same time, the distance between the first through hole and the two long sides of the first upper end face is equal and ≥D / 2+0.4mm, where D is the inner diameter of the first through hole.

6. A high-energy, high-safety lithium battery according to claim 1, characterized in that: Both the upper surface and the groove are rectangular, and the width of both is equal to the width of the shell.

7. A high-energy, high-safety lithium battery according to claim 1, characterized in that: The second through hole is a rectangular hole with a height of A1 and a width of B1, where A1*B1≥Smin; where Smin is the minimum value of the current-carrying area, Smin=I / J, where I is the battery current I, and J is the maximum current density; the distance between the second through hole and the edge of the upper end face is equal and ≥0.8mm; the center distance between the first through hole and the second through hole is ≥B1 / 2+D / 2+0.4mm, where D is the inner diameter of the first through hole.

8. A high-energy, high-safety lithium battery according to claim 1, characterized in that: The battery cell also includes several stacked electrode sheets. Each electrode sheet is a rectangular sheet with a tab extending from one side. The electrode sheet has an upper rounded corner on the side near the tab and two lower rounded corners on the side away from the tab. The radius of the upper rounded corner is greater than or equal to the radius of the lower rounded corner.

9. A high-energy, high-safety lithium battery according to claim 8, characterized in that: The electrode has a U-shaped groove below it, and the resulting battery cell is a battery cell with a U-shaped groove on top.

10. A high-energy, high-safety lithium battery according to claim 9, characterized in that: The electrode sheets are divided into two types of structures. One type is a rectangular sheet with an extended tab on one side, and the other type is a rectangular sheet with a U-shaped groove on one side of the tab. When the two types of electrode sheets are stacked, a battery cell is formed with part of it being rectangular and part of it being rectangular with a U-shaped groove. The electrode corresponding to the groove is the first electrode, and the electrode corresponding to the upper end face is the second electrode. The first tab of the first electrode is connected to the electrode post assembly, the second tab of the first electrode is connected to the upper end face, the first tab of the second electrode is connected to the electrode post assembly, and the second tab of the second electrode is connected to the second side of the groove.

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