Battery monomer, battery pack and vehicle
By designing a structure that separates the cavities in the lithium-ion battery cell, it ensures that the electrolyte can fully infiltrate each cell, solving the problem of insufficient cell infiltration after the electrolyte is consumed, extending the cycle life of the battery and maintaining the battery life. core performance.
Patent Information
- Application Number
- CN202420027335.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-05
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-01-05
AI Technical Summary
During the charging and discharging cycle of lithium-ion batteries, electrolyte consumption leads to insufficient infiltration of the battery cell, resulting in increased lithium extraction or internal resistance, rapid attenuation of cycle life and sudden drop in capacity and power performance.
Design a battery cell. The inside of the casing is divided into upper and lower cavities by insulating partitions. The battery cores are placed in each cavity respectively. The electrode ear groups are connected through the via holes on the insulating partitions to ensure that the electrolyte can be effectively infiltrated. to each cell.
By reducing the height of a single battery cell, the gravity that the electrolyte needs to overcome is reduced, the capillary force is increased, the electrolyte infiltration speed and efficiency are improved, and the lithium precipitation or internal resistance growth after the electrolyte is consumed is avoided, thereby extending the cycle life and maintaining the battery core. capacity function performance.
Smart Images
Figure CN222380629U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of new energy batteries, in particular to a battery monomer, a battery pack and a vehicle. Background Art
[0002] During the charge and discharge cycle, lithium ions in lithium-ion batteries are intercalated and deintercalated back and forth between the two electrodes through the electrolyte. As the electrolyte is consumed, the length of the cell that is soaked will shorten, and the upper part and corners of the cell are more likely to be unable to be soaked due to the drying of the electrolyte, thus causing serious lithium precipitation or internal resistance growth, resulting in rapid attenuation of cycle life and a sharp drop in capacity and power performance. Utility Model Content
[0003] The utility model provides a battery cell, a battery pack and a vehicle, which are used to solve the problem of insufficient infiltration of the battery core after the electrolyte is consumed in the prior art.
[0004] The technical solution of the utility model is:
[0005] The utility model provides a battery monomer, comprising:
[0006] A shell, the interior of which is divided into at least two cavities arranged up and down by an insulating partition, and each of the insulating partitions is provided with a via hole connecting two adjacent cavities;
[0007] A cover plate, which seals the topmost cavity of the shell, and is provided with a liquid injection port, a pole group and an explosion-proof valve;
[0008] A battery cell, wherein one battery cell is placed in each cavity;
[0009] A first electrode tab group is arranged on the top of the battery cell in the topmost cavity, and a second electrode tab group is arranged on the sides of the battery cells in the other layers of cavities;
[0010] The first electrode tab group is electrically connected to the electrode column group arranged on the cover plate, and each of the second electrode tab groups is electrically connected to the first electrode tab group after a connecting pin passes through a via hole on the insulating partition.
[0011] Furthermore, a blocking member disposed around the via hole protrudes from the upper surface or the lower surface of each of the insulating partitions.
[0012] Furthermore, the battery core is a stacked core or a wound core.
[0013] Furthermore, when the battery core is a wound core, the inner diaphragm and the outer diaphragm of the battery core located in the topmost cavity are adhered together on the side facing the cover plate by an insulating material.
[0014] Furthermore, the bursting pressure of the insulating partition and the shell is smaller than the bursting pressure of the explosion-proof valve.
[0015] Furthermore, the bottommost cavity of the shell is closed by a bottom tray.
[0016] On the other hand, the utility model also provides a battery pack, comprising:
[0017] Box;
[0018] And the battery cell mentioned above, the battery cell is multiple, and the multiple battery cells are electrically connected;
[0019] The plurality of battery cells are inverted in the box, and the pole group and explosion-proof valve of each battery cell are oriented downward in the box.
[0020] On the other hand, the utility model also provides a vehicle, comprising the above-mentioned battery pack.
[0021] The beneficial effects of the utility model are:
[0022] The height of the shell is the same as the height of a single-cell battery cell in the prior art. After the shell is set into at least two cavities arranged longitudinally, the number of cells filled inside the shell becomes two. Since the height of the shell is not adjusted, the single height of the two cells is lower than the cell height of a single-cell battery cell in the prior art. Since the wetting effect of the electrolyte on the battery cell is affected by the capillary force and its own gravity, the height of a single battery cell in this solution becomes lower, and the amount of electrolyte required to fully wet a single battery cell will also decrease, thereby reducing the gravity that the electrolyte needs to overcome; at the same time, according to the formula: F=ηπr^4 / 8L, F represents the capillary force, η represents the liquid viscosity of the electrolyte, r represents the radius of the capillary, and L represents the length of the capillary. After the height of a single battery cell becomes lower, the length L of the capillary will become shorter, which will increase the capillary force; for the electrolyte, the gravity it needs to overcome is reduced, and the capillary force supporting its upward wetting increases, so the wetting speed of the battery cell will become faster; in addition, after the electrolyte is partially consumed, the height of the electrolyte wetted will be increased compared to the prior art. This can avoid the serious lithium precipitation or internal resistance growth problem after the electrolyte is partially consumed, and prevent the rapid decay of the cycle life and the sudden drop in the capacity and performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic diagram of the structure of a battery cell in an embodiment of the utility model;
[0024] Figure 2 It is a structural schematic diagram of the housing in the embodiment of the utility model;
[0025] Figure 3This is a schematic diagram of the structure of the first battery cell in an embodiment of the utility model;
[0026] Figure 4 This is a schematic diagram of the structure of the second battery cell in an embodiment of the utility model;
[0027] Figure 5 This is a schematic diagram of the diaphragm closure principle of the first battery cell in an embodiment of the utility model;
[0028] Explanation of the reference numerals: 11-shell; 12-bottom tray; 21-first battery cell; 22-second battery cell; 111-insulating partition; 112-upper cavity; 113-lower cavity; 1111-via; 1112-blocking plate; 3-cover plate; 31-positive pole; 32-negative pole; 33-liquid filling port; 34-explosion-proof valve; 41-positive electrode connecting pin; 42-negative electrode connecting pin; 211-first positive electrode ear; 212-second negative electrode ear; 221-second negative electrode ear; 213-outer diaphragm; 214-inner diaphragm. DETAILED DESCRIPTION
[0029] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0030] The embodiment of the utility model provides a battery cell, comprising: a housing 11, a cover plate 3 and a battery cell.
[0031] As for the housing 11 , its interior is divided into at least two cavities arranged up and down by an insulating partition 111 , and each insulating partition 111 is provided with a via 1111 for connecting two adjacent cavities.
[0032] The insulating partition 111 can be a plate directly supported by an insulating material, or it can be an insulating layer formed on the outer surface of the plate by coating, bonding or welding. Compared with the traditional bundled core parallel design, the design of the insulating partition 111 can alleviate the heat transfer between the battery cells to a certain extent. It is expected that the innovation of the material, structure and coating of the insulating partition 111 can realize the heat diffusion-free design between the battery cells, and further improve the safety performance of electric vehicles. For example, the thickness of the insulating partition 111 is 0.4~1mm, and the outer surface is coated with an insulating layer with a thickness of 0.1~0.2mm to ensure the electrical insulation between the connecting pins and the shell 11.
[0033] In addition, in the embodiment of the utility model, the insulating partition 111 can be fixed inside the shell 11 by welding or integrally formed with the shell 11 .
[0034] As for the cover plate 3 , it seals the topmost cavity of the shell 11 , and a liquid injection port 33 , a pole group and an explosion-proof valve 34 are provided on the cover plate 3 .
[0035] For the battery cells, one battery cell is placed in each cavity. Figures 2 to 4 In this embodiment, the battery cell located in the topmost layer cavity is referred to as the first battery cell 21, and the battery cells located in other layers of the cavity are referred to as the second battery cells 22.
[0036] Considering that the battery of a pure electric vehicle is generally placed at the bottom of the vehicle, in order to avoid the problem of the vehicle's center of gravity being increased due to the battery pack being too high, in the specific diagram of this embodiment, Figure 1 , the insulating partition 111 inside the shell 11 is provided as only one piece, that is, the cavity inside the shell 11 is provided as two upper and lower independent cavities. Therefore, in this embodiment, the first battery cell 21 and the second battery cell 22 in one battery cell are both one.
[0037] In addition, in order to avoid the battery pack being too high, in this embodiment, the height of the first battery cell 21 and the second battery cell 22 can be shortened so that the sum of the overall heights of the first battery cell 21 and the second battery cell 22 can be similar to or even equal to the height of an existing single battery cell without changing the battery capacity of the battery cell.
[0038] The upper cavity inside the shell 11 is covered by the cover plate 3, and the lower cavity inside the shell 11 is also covered by the bottom plate of the shell 11 or a separately provided bottom tray 12. When a separate bottom tray 12 is used, the shell 11 and the bottom tray 12 are fixed by welding or the like.
[0039] In this embodiment, the shell 11 can be selected as a metal shell 11, such as a shell 11 made of aluminum alloy, magnesium alloy, steel, etc. The metal shell 11 uses its high mechanical strength and thermal conductivity to effectively resist external impact and temperature changes and protect the battery core; the shell 11 can also be made of composite materials, such as carbon fiber reinforced composite materials. The thermal conductivity of the carbon fiber reinforced composite material shell 11 is better than that of the metal shell 11, and the performance of resisting high and low temperatures is better.
[0040] like Figure 3 and Figure 4 A first pole lug group is arranged on the top of the first battery cell 21, and a second pole lug group is respectively arranged on the side of the second battery cell 22; the first pole lug group is electrically connected to the pole column group arranged on the cover plate 3, and each second pole lug group is electrically connected to the first pole lug group after passing through the through hole 1111 on the insulating partition 111 through the connecting pin.
[0041] The first electrode tab group includes a first positive electrode tab 211 and a first negative electrode tab 212, the second electrode tab group includes a second positive electrode tab and a second negative electrode tab 221, and the electrode column group also includes a positive electrode column 31 and a negative electrode column 32. The positive electrode tab and the negative electrode tab of the second electrode tab group are symmetrically arranged at both ends of the second battery cell 22, and the first positive electrode tab 211 and the first negative electrode tab 212 of the first electrode tab group are arranged on the side facing the cover plate 3.
[0042] The electrical connection between the positive electrode tabs of the first electrode tab group and the second electrode tab group is achieved through the positive electrode connection pin 41, and the electrical connection between the negative electrode tabs of the first electrode tab group and the second electrode tab group is achieved through the negative electrode connection pin 42. Vias 1111 are provided at both ends of the insulating partition 111, and the positive electrode connection pin 41 and the negative electrode connection pin 42 pass through the vias 1111 at corresponding positions respectively, and there is also a gap between the two connection pins and the vias 1111 through which the electrolyte flows.
[0043] In this embodiment, after the shell 11 is configured into at least two cavities arranged longitudinally, the electrolyte is injected into the upper cavity 112 of the shell 11 from the injection port 33 on the cover plate 3, and then further flows into the lower cavity 113 through the via 1111 on the insulating partition 111.
[0044] The height of the shell is the same as the height of a single-cell battery cell in the prior art. After the shell is set to at least two cavities arranged longitudinally, the number of cells filled inside the shell 11 becomes two. Since the height of the shell is not adjusted, the single height of the two cells is lower than the cell height of a single-cell battery cell in the prior art. Since the wetting effect of the electrolyte on the battery cell is affected by the capillary force and its own gravity, the height of a single battery cell in this solution becomes lower, and the demand for electrolyte to fully wet the single battery cell will also decrease, thereby reducing the gravity that the electrolyte needs to overcome; at the same time, according to the formula: F=ηπr^4 / 8L, F represents capillary force, η represents the liquid viscosity of the electrolyte, r represents the radius of the capillary, and L represents the length of the capillary, after the height of a single battery cell becomes lower, the length L of the capillary will become shorter, which will increase the capillary force; for the electrolyte, the gravity it needs to overcome is reduced, and the capillary force supporting it to wet upward is increased, so the wetting speed of the battery cell will become faster; in addition, after the electrolyte is partially consumed, the height of the electrolyte wetted will be increased compared to the prior art.
[0045] The electrolyte in each cavity wets the battery cell in its cavity respectively, and the length of the battery cell that needs to be wetted by the electrolyte in each cavity is longer than the length of the battery cell that needs to be wetted by the electrolyte in a single cavity in the prior art. When the battery pack is used for cyclic charge and discharge, although the electrolyte in each cavity is consumed, the remaining electrolyte in each cavity can still partially wet the battery cell in each cavity, thereby avoiding serious lithium deposition or internal resistance growth problems, and preventing the rapid attenuation of cycle life and the sudden drop in battery cell capacity and performance.
[0046] In some embodiments of the present invention, in order to prevent the electrolyte in the upper cavity from completely flowing into the electrolyte in the lower cavity during the charge and discharge cycle, a blocking member 1112 is protruded from the upper or lower surface of the insulating partition 111 and is arranged around the via 1111. The height of the blocking member 1112 can be selected and matched according to the performance and life of the battery cell. During the injection of fresh battery cells, part of the electrolyte flows into the lower cavity 113 through the height of the blocking member 1112 to wet the second battery cell 22. In the later stage of the cycle, this design can ensure that the upper and lower cells respectively maintain a certain amount of electrolyte.
[0047] When the battery cell is inverted in the battery box, Figure 2 The lower cavity 113 in the cavity becomes the upper cavity 112. Figure 2 The upper cavity 112 in the housing 11 is used as the lower cavity 113 by arranging the blocking member 1112 on the lower surface of the insulating partition 111 facing the bottom of the housing 11 .
[0048] When the battery cell is placed upright in the battery box, the blocking member 1112 may be disposed on the upper surface of the insulating partition 111 facing the cover plate 3 .
[0049] In order to improve the safety of the battery system in the vehicle, the prior art provides a design method of inverting the battery cell in the battery case, so that the pole and explosion-proof valve 34 of each battery cell are located at the bottom of the battery case. When the explosion-proof valve 34 is opened, the impact of thermal runaway exhaust on the passenger compartment can be avoided. However, this arrangement has the problem of the pole ear being squeezed and inserted inverted due to the excessive gravity of the winding core itself, and the risk of short circuit between the positive and negative electrodes due to excessive downward pressure on the diaphragm by the gravity of the winding core itself, which further avoids the risk of fire and explosion of the battery cell and improves vehicle safety.
[0050] In the embodiment of the utility model, the inner diaphragm and the outer diaphragm of the first battery cell 21 located in the topmost cavity are pasted together by an insulating material on the side facing the cover plate 3. The insulating material can be made of insulating glue, and the insulating glue is made of glue with liquid absorption function. This design can avoid the risk of the battery cell squeezing the pole ear due to excessive gravity during the inversion process, causing the pole ear to be inserted inverted and embedded between the pole pieces to cause a short circuit.
[0051] like Figure 5 In this embodiment, the first battery cell 21 is assembled by a winding or lamination process. During the assembly process, the equipment automatically applies insulating liquid-absorbing glue to the inner diaphragm 214 and the outer diaphragm 213 on the side close to the cover plate 3. The coating width is between 0.2 and 3 mm. During the winding or lamination and subsequent cold pressing process, the inner diaphragm 214 and the outer diaphragm 213 are automatically adhered to each other, isolating the positive and negative electrodes inside the winding core, and the physical contact between the tabs and the positive or negative electrodes, avoiding the risk of short circuit, thereby playing the role of end sealing.
[0052] The utility model also provides a battery pack, comprising:
[0053] Box;
[0054] And the battery cell mentioned above, the battery cell is multiple, and the multiple battery cells are electrically connected;
[0055] A plurality of battery cells are inverted in the box, and the pole group and explosion-proof valve 34 of each battery cell are facing downward in the box.
[0056] The utility model also provides a vehicle, comprising the above-mentioned battery pack.
[0057] In some embodiments of the present invention, the bursting pressure of the insulating partition 111 and the shell 11 is also set to be lower than the bursting pressure of the explosion-proof valve 34, to ensure that when the second battery cell 22 located in the lower cavity 113 has thermal runaway, it can still break through the insulating partition 111 and release the pressure in a direction through the explosion-proof valve 34.
[0058] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0059] Although the preferred embodiments of the utility model embodiments have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the utility model embodiments.
[0060] It should also be noted that, in this article, the orientation or position relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, relational terms such as "first" and "second" are used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations, nor can they be understood as indicating or implying relative importance. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements does not include those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.
[0061] The technical solution provided by the utility model is described in detail above. The principle and implementation method of the utility model are described in this article using specific examples. The description of the above embodiments is only used to help understand the utility model, and the content of this specification should not be understood as limiting the utility model. At the same time, for those skilled in the art, according to the utility model, there will be different forms of changes in the specific implementation methods and application scopes. It is not necessary and impossible to list all the implementation methods here, and the obvious changes or modifications derived from them are still within the protection scope of the utility model.
Claims
1. A battery cell, characterized in that: include: A housing (11), the interior of which is divided into at least two cavities arranged up and down by an insulating partition (111), and each of the insulating partitions (111) is provided with a via hole (1111) for connecting two adjacent cavities; A cover plate (3) which seals the topmost cavity of the housing (11), and the cover plate (3) is provided with a liquid injection port (33), a pole group and an explosion-proof valve (34); A battery cell, wherein one battery cell is placed in each cavity; A first electrode tab group is arranged on the top of the battery cell in the topmost cavity, and a second electrode tab group is arranged on the sides of the battery cells in the other layers of cavities; The first electrode lug group is electrically connected to a pole group provided on the cover plate (3), and each of the second electrode lug groups is electrically connected to the first electrode lug group after passing through a via (1111) on the insulating partition (111) via a connecting pin.
2. The battery cell according to claim 1, characterized in that: A blocking member (1112) arranged around the through hole (1111) protrudes from the upper surface or the lower surface of each insulating partition (111).
3. The battery cell according to claim 1, characterized in that: The battery core is a stacked core or a wound core.
4. The battery cell according to claim 1, characterized in that: When the battery core is a rolled core, the inner diaphragm and the outer diaphragm of the battery core located in the topmost cavity are adhered together on the side facing the cover plate (3) by an insulating material.
5. The battery cell according to claim 1, characterized in that: The bursting pressure of the insulating partition (111) and the shell (11) is lower than the bursting pressure of the explosion-proof valve (34).
6. The battery cell according to claim 1, characterized in that: The bottommost cavity of the shell (11) is closed by a bottom tray (12).
7. A battery pack, characterized in that: include: Box; and the battery cell according to any one of claims 1 to 6, wherein the battery cell is multiple and the multiple battery cells are electrically connected; The plurality of battery cells are inverted in the box, and the pole group and explosion-proof valve (34) of each battery cell are oriented downward in the box.
8. A vehicle, characterized in that: Comprising the battery pack as claimed in claim 7.