Bipolar lithium battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a bipolar lithium battery cell which comprises a battery cell shell (1), an elastic sealing element (2), a positive electrode current collector (3), a positive electrode material (4), an intermediate current collector (5), a negative electrode material (6), a diaphragm electrolyte group (7) and a negative electrode current collector (8), the bipolar lithium battery cell is made into a single body with high voltage, and under the same output power, the current of the battery cell is small, the temperature rise is small, and the safety is high; internal elements of the battery cell are similar to series stacking, current flows from the pole pieces to the pole pieces, tabs are not needed, parts are reduced, the connection resistance is reduced, the structure is simplified, and the energy density is high; the consumption of copper is greatly reduced, the weight is reduced, and the cost is reduced; according to the bipolar lithium battery cell, liquid injection and infiltration are carried out outside the battery cell, the process controllability is high, the infiltration degree is high, infiltration is uniform, the speed is high, and the consistency of the battery cell is high.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, and in particular to a bipolar lithium battery cell. Background Art

[0002] Lithium batteries are one of the main sources of power. The current mainstream battery cells adopt a single low-voltage structure. Since they are used as a power source, the battery output voltage is required to be higher. The battery system needs to combine multiple battery cells in series to obtain the required high voltage. When connected in series, the battery cell voltages are superimposed, the battery cell current is large, the battery cell loses a lot of power, generates a lot of heat, and has low safety.

[0003] A bipolar lithium battery cell involved in the present application has at least the following beneficial technical effects: the bipolar lithium battery cell is made into a single high voltage, and under the same output power, the current of the battery cell is small, the temperature rise is small, and the safety is high; the internal components of the battery cell are similar to series stacking, and the current flows from pole piece to pole piece, and no pole ears are required, which reduces parts, reduces connection resistance, simplifies structure, and has high energy density; greatly reduces the use of copper, reduces weight, and reduces costs; liquid injection and infiltration are performed on the outside of the battery cell, and the process is highly controllable, the infiltration degree is high, the infiltration is uniform, the speed is fast, and the consistency of the battery cell is high. Summary of the invention

[0004] The purpose of the present application is to provide a bipolar lithium battery cell, which is made into a single high voltage, reduces the amount of copper used, and the internal components of the battery cell are similar to series stacking, without the need for tabs, and liquid injection and infiltration are performed on the outside of the battery cell.

[0005] The technical solution of the present application is: a bipolar lithium battery cell, comprising a battery cell housing (1), an elastic sealing element (2), a positive electrode current collector (3), a positive electrode material (4), an intermediate current collector (5), a negative electrode material (6), a diaphragm electrolyte group (7), and a negative electrode current collector (8);

[0006] The battery cell shell (1) is the external structure of the battery cell and is used to protect the internal components of the battery cell. It can be made of high-quality aluminum, stainless steel, etc.; the elastic sealing element (2) is installed between the outer surface of the positive electrode current collector (3) or the negative electrode current collector (8) or both and the shell, and plays the role of sealing the battery cell and applying a compressive force to the internal components of the battery cell stacked in sequence. When the battery cell expands due to heat, it bears and alleviates the expansion force of the internal components of the battery cell; the positive electrode material (4) is the main source of lithium ions in the lithium battery cell; the negative electrode material (6) is the carrier of lithium ions and electrons in the lithium battery cell during charging; the positive electrode current collector (3), the intermediate current collector (5), and the negative electrode current collector (8) are used to connect the active substances, collect and output the current generated by the active substances, and input the current to the active substances;

[0007] The positive electrode current collector (3) is made into a thin sheet; the main material of the positive electrode current collector (3) is aluminum foil; the outer surface of the positive electrode current collector (3) can be used as the positive electrode lead-out terminal of the battery cell; the inner surface of the positive electrode current collector (3) is coated with a positive electrode material (4); during charging and discharging, since the current is input and output from one side of the thin sheet-shaped positive electrode current collector (3) to the other side, the internal resistance is small;

[0008] The negative electrode current collector (8) is made into a thin sheet; the main material of the negative electrode current collector (8) is aluminum foil with a copper layer, the outer surface is aluminum, and the inner surface is copper; the outer surface of the negative electrode current collector (8) can be used as the negative electrode lead-out terminal of the battery cell; the inner surface of the negative electrode current collector (8) is coated with a negative electrode material (6); during charging and discharging, since the current is input and output from one side of the thin sheet of the negative electrode current collector (8) to the other side, the internal resistance is small;

[0009] The outer surfaces of the positive and negative current collectors refer to the surfaces facing the outside of the battery cell; the inner surfaces of the positive and negative current collectors refer to the surfaces facing the inside of the battery cell;

[0010] The intermediate current collector (5) is made into a thin sheet; the main material of the intermediate current collector (5) is aluminum foil with a copper layer, one side of the surface is aluminum, and the other side of the surface is copper; the aluminum surface of the intermediate current collector (5) is coated with a positive electrode material (4), and the copper surface of the intermediate current collector (5) is coated with a negative electrode material (6); during charging and discharging, since the current is input and output from one side to the other side of the thin sheet-shaped intermediate current collector (5), the internal resistance is small;

[0011] During charging and discharging, the current flows from one side of the thin sheet current collector to the other side. Since the sheet is very thin, the internal resistance is much smaller and more uniform than that of a conventional current collector where the current flows from one end to the other.

[0012] The above current collector significantly reduces the amount of copper used, reduces weight and reduces costs;

[0013] The function of the diaphragm electrolyte group (7) is to separate the positive and negative electrodes of the battery cell and is a carrier for ion transmission in the lithium battery cell; the diaphragm of the diaphragm electrolyte group (7) is selected to have a higher porosity and a larger pore size; the inside (or similar inside) of the diaphragm of the diaphragm electrolyte group (7) is adsorbed with a gel (or quasi-gel) electrolyte; the mechanical strength of the diaphragm electrolyte group (7) is mainly provided by the diaphragm, and the gel (or quasi-gel) electrolyte is not required to have a high mechanical strength, thereby reducing the requirements for the gel (or quasi-gel) electrolyte; the diaphragm electrolyte group (7) is adsorbed by the diaphragm The diaphragm electrolyte group (7) is stabilized by the ability to absorb the electrolyte and the immobility of the gel electrolyte. A diaphragm with strong electrolyte adsorption is selected. When the electrolyte is not completely transformed into a gel state or the electrolyte has some fluidity, the electrolyte will not leak from the diaphragm electrolyte group (7), thereby reducing the requirements for the immobility of the gel (or quasi-gel) electrolyte. Since the requirements for the mechanical strength and gelation degree of the electrolyte gelation are reduced, the electrolyte can maintain good ion transmission performance. The diaphragm electrolyte group (7) has high ion conductivity, low internal resistance of the battery cell, low manufacturing difficulty and low cost.

[0014] The manufacturing method of the diaphragm electrolyte group (7) is as follows: the diaphragm is filled with a liquid electrolyte to which a coagulation factor or the like is added in a certain method and infiltrated; after the infiltration is completed, the liquid electrolyte adsorbed in the pores of the diaphragm is converted into a gel (or a gel-like) electrolyte in a certain manner, and then frozen; the diaphragm adsorbed with the gel (or a gel-like) electrolyte is frozen, and then sliced ​​to obtain the sliced ​​and frozen diaphragm electrolyte group (7); then the diaphragm electrolyte group (7) is stacked with other components of the battery cell in a certain method, and then thawed to obtain the diaphragm electrolyte group (7) inside the battery cell; it is convenient to pick up or stack the frozen diaphragm electrolyte group (7);

[0015] The bipolar lithium battery cell is injected and soaked on the outside of the battery cell, and the injection and soaking process is highly controllable, with high soaking degree, uniform soaking, fast speed and high consistency;

[0016] The bipolar lithium battery cell is composed of the positive electrode current collector (3) coated with the positive electrode material (4), two or more separator electrolyte groups (7), two or more intermediate current collectors (5) with the positive electrode material (4) or the negative electrode material (6) coated on both sides respectively, and a negative electrode current collector (8) coated with the negative electrode material (6), which are stacked in sequence;

[0017] The positive electrode material (4) coated by the positive electrode collector (3) is stacked with the separator electrolyte group (7) at the back (or a similar back), and then the negative electrode material (6) coated by the intermediate current collector (5) is stacked at the back (or a similar back). The positive electrode material (4) coated by the intermediate current collector (5) is stacked with the separator electrolyte group (7), and then the separator electrolyte group (7) is stacked with the negative electrode material (6) coated by the next intermediate current collector (5); the positive electrode material (4) coated by the intermediate current collector (5) is stacked with the separator electrolyte group (7) at the back (or a similar back), and then the separator electrolyte group (7) is stacked with the negative electrode material (6) coated by the negative electrode collector (8) at the back (or a similar back).

[0018] The bipolar lithium battery cell has no pole ears inside, and the current flows from pole piece to pole piece, which reduces the number of parts, reduces the connection resistance, simplifies the structure, and has high energy density.

[0019] Unless otherwise defined, the technical terms or scientific terms used in the description of this application shall be the common meanings understood by the general technicians in the field to which this application belongs. In the description of this application, the terms "outer", "inner", "a section", "a level", "import", "export", "axial", "tangential", "inner diameter", "outer diameter", "interlaced", "corresponding", "circumference", "certain", "last", etc. indicate the position or position relationship, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the devices and elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, "first level", "next level", "step by step", "a module unit", "last level" and similar terms are only used for descriptive purposes to distinguish different components, and cannot be understood as indicating or implying relative importance. The words "one", "a level" and the like used in the description of this application should not be understood as an absolute limitation on the number, but should be understood as the existence of at least one. The words "deflected downward 90 degrees", "horizontally backward" and the like used in the description of this application should not be understood as an absolute limitation on the degree, but should be understood as including "deflected downward 90 degrees" and "horizontally backward". The words "including", "or", "or" and the like used in the description of this application mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects;

[0020] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "connect", "assembly", "installation", "combination", "connection" and similar words used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a bipolar lithium battery provided in an embodiment of the present application;

[0022] Wherein: 1-cell shell, 2-elastic sealing element, 3-positive electrode current collector, 4-positive electrode material, 5-intermediate current collector, 6-negative electrode material, 7-diaphragm electrolyte group, 8-negative electrode current collector;

[0023] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; in addition, the drawings are used for illustrative purposes, and the terms describing the positional relationships therein are limited to illustrative purposes and cannot be understood as limitations on this patent. DETAILED DESCRIPTION

[0024] The specific embodiments described herein are only some embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0025] The following is a supplementary description of this application in conjunction with the accompanying drawings;

[0026] Figure 1 In an embodiment, the battery cell housing (1) has two corresponding surfaces that are not fully covered, and the middle parts of the two corresponding surfaces are not covered, exposing part of the outer surface of the positive electrode aluminum foil current collector (3) and the negative electrode current collector (8); the inner surface of the battery cell housing (1) is provided with an insulating layer; the positive electrode aluminum foil current collector (3) can be used as a shell surface of the battery, is relatively thick, and has sufficient strength, and the outer surface of the positive electrode aluminum foil current collector (3) can be used as the positive electrode lead-out terminal of the battery cell; the negative electrode current collector (8) can be used as a shell surface of the battery, is relatively thick, and has sufficient strength; the outer surface of the negative electrode current collector (8) can be used as the negative electrode lead-out terminal of the battery cell;

[0027] The elastic sealing element (2) is installed between the periphery of the outer surface of the positive electrode current collector (3) and the shell, and can seal the battery cell. The initial elastic deformation during installation applies a compressive force to the internal components of the battery cell stacked in sequence. When the battery cell expands due to heat, the expansion force of the internal components of the battery cell is borne and alleviated through deformation.

[0028] The function of the diaphragm electrolyte group (7) is to separate the positive and negative electrodes of the battery cell and is a carrier for ion transmission in the lithium battery cell; the diaphragm of the diaphragm electrolyte group (7) is selected to have a higher porosity, a larger pore size and is relatively hard; the inside (or similar inside) of the diaphragm of the diaphragm electrolyte group (7) is adsorbed with a gel (or quasi-gel) electrolyte; the mechanical strength of the diaphragm electrolyte group (7) is mainly provided by the diaphragm, and the gel (or quasi-gel) electrolyte is not required to have a high mechanical strength, thereby reducing the need for the gel (or quasi-gel) electrolyte. The diaphragm electrolyte group (7) is stabilized by the ability of the diaphragm to adsorb electrolyte and the immobility of the gel (or quasi-gel) electrolyte. The diaphragm with strong electrolyte adsorption is selected to reduce the requirements for the gel (or quasi-gel) electrolyte. Since the requirements for the mechanical strength and degree of gelation of the electrolyte gel are reduced, the electrolyte can maintain good ion transmission performance. The diaphragm electrolyte group (7) has high ion conductivity, low internal resistance of the battery cell, low manufacturing difficulty and low cost.

[0029] The method for making the diaphragm electrolyte group (7) is as follows: a liquid electrolyte to which a coagulation factor or the like is added in a certain method is added to the cut and dried diaphragm; after the infiltration is completed, the liquid electrolyte adsorbed in the pores of the diaphragm is converted into a gel (or a gel-like) electrolyte in a certain manner; after the conversion is completed, freezing is performed to freeze the diaphragm adsorbed with the gel (or a gel-like) electrolyte, and then slicing is performed to obtain a frozen diaphragm electrolyte group (7); the diaphragm electrolyte group (7) is then stacked with other components of the battery cell in a certain method; after the stacking is completed, the diaphragm electrolyte group (7) is thawed to obtain the diaphragm electrolyte group (7) inside the battery cell;

[0030] The bipolar lithium battery cell is injected and soaked on the outside of the battery cell, and the separator can be rolled and injected and soaked at the same time when it is pressed and relaxed. After a single or multiple repetitions, the electrolyte soaking degree of the separator is high and the soaking is uniform. The injection and soaking process is controllable, the speed is fast, the cost is reduced, and the consistency of the battery cell is high.

[0031] After the infiltration is completed, the liquid electrolyte adsorbed in the pores of the diaphragm is converted into a gel (or quasi-gel) electrolyte in a certain manner. After the conversion is completed, the diaphragm adsorbed with the gel (or quasi-gel) electrolyte is frozen, and after freezing, the diaphragm is sliced ​​into required sizes to obtain a frozen diaphragm electrolyte group (7), which is convenient to pick up or stack.

[0032] After entering the lamination stage, the battery cell shell (1) is first placed vertically, with the positive electrode on the top and the negative electrode on the bottom. The negative electrode current collector (8) coated with the negative electrode material (5) is first placed into the shell, with the outer surface of the negative electrode current collector (8) facing downward and the surface coated with the negative electrode material (5) facing upward; then, a diaphragm electrolyte group (7) is stacked on the negative electrode material (5) coated on the negative electrode current collector (8); then, the intermediate current collector (5) coated with the positive electrode material (4) on one side and the negative electrode material (6) on the other side is stacked on the stacked diaphragm electrolyte group (7), with the surface coated with the positive electrode material (4) facing downward and the other side coated with the negative electrode material (6) facing upward; then, a next diaphragm electrolyte group (7) is stacked on the negative electrode material (6) coated on the intermediate current collector (5); then, the next diaphragm electrolyte group (7) is stacked on the next stacked The intermediate current collector (5) coated with a positive electrode material (4) on one side and a negative electrode material (6) on the other side is stacked on the diaphragm electrolyte group (7), with the side coated with the positive electrode material (4) facing downward and the other side coated with the negative electrode material (6) facing upward; the stacking is repeated, and then the positive electrode current collector (3) coated with the positive electrode material (4) is stacked, with the outer surface of the positive electrode current collector (3) facing upward and the side coated with the positive electrode material (4) facing downward; thawing is performed, and then the elastic sealing element (2) is placed, and finally the side cover of the battery cell housing (1) is placed, pressed, and then the side cover of the battery cell housing (1) is welded to obtain an assembled battery cell, and the battery cell is laid flat to balance the pressing force on the internal components of the battery cell, and then processed according to the conventional process to obtain the bipolar lithium battery cell;

[0033] The bipolar lithium battery cell has no pole ears inside, and the current flows from pole piece to pole piece, which reduces the number of parts, reduces the connection resistance, simplifies the structure, and has high energy density.

Claims

1. A bipolar lithium battery cell, characterized in that: The bipolar lithium battery cell comprises a battery cell housing (1), an elastic sealing element (2), a positive electrode current collector (3), a positive electrode material (4), an intermediate current collector (5), a negative electrode material (6), a diaphragm electrolyte group (7), and a negative electrode current collector (8).

2. The bipolar lithium battery cell according to claim 1, characterized in that: The battery cell shell (1) is the external structure of the battery cell and is used to protect the internal components of the battery cell. It can be made of high-quality aluminum, stainless steel and other materials. The elastic sealing element (2) is installed between the outer surface of the positive electrode current collector (3) or the negative electrode current collector (8) or both and the shell, and plays the role of sealing the battery cell and applying a compressive force to the internal components of the battery cell stacked in sequence. When the battery cell expands due to heat, it bears and alleviates the expansion force of the internal components of the battery cell. The positive electrode material (4) is the main source of lithium ions in the lithium battery cell. The negative electrode material (6) is the carrier of lithium ions and electrons in the lithium battery cell during charging. The positive electrode current collector (3), the intermediate current collector (5) and the negative electrode current collector (8) have the function of connecting the active substances, collecting and outputting the current generated by the active substances, and inputting the current into the active substances.

3. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The positive electrode current collector (3) is made into a thin sheet; the main material of the positive electrode current collector (3) is aluminum foil; the outer surface of the positive electrode current collector (3) can be used as the positive electrode lead-out terminal of the battery cell; and the inner surface of the positive electrode current collector (3) is coated with a positive electrode material (4).

4. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The negative electrode current collector (8) is made into a thin sheet; the main material of the negative electrode current collector (8) is aluminum foil with a copper layer, the outer surface is aluminum, and the inner surface is copper; the outer surface of the negative electrode current collector (8) can be used as the negative electrode lead-out terminal of the battery cell; the inner surface of the negative electrode current collector (8) is coated with a negative electrode material (6).

5. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The intermediate current collector (5) is made into a thin sheet; the main material of the intermediate current collector (5) is aluminum foil with a copper layer, one side of the surface is aluminum, and the other side of the surface is copper; the aluminum surface of the intermediate current collector (5) is coated with a positive electrode material (4), and the copper surface of the intermediate current collector (5) is coated with a negative electrode material (6).

6. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The function of the diaphragm electrolyte group (7) is to separate the positive and negative electrodes of the battery cell and is a carrier for ion transmission in the lithium battery cell; the interior (or similar interior) of the diaphragm of the diaphragm electrolyte group (7) is adsorbed with a gel (or quasi-gel) electrolyte; the mechanical strength of the diaphragm electrolyte group (7) is mainly provided by the diaphragm, and the gel (or quasi-gel) electrolyte is not required to have a high mechanical strength, thereby reducing the requirements for the gel (or quasi-gel) electrolyte; the diaphragm electrolyte group (7) selects a diaphragm with strong electrolyte adsorption, thereby reducing the requirements for the degree of immobility of the gel (or quasi-gel) electrolyte.

7. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The method for making the diaphragm electrolyte group (7) is as follows: the diaphragm is filled with a liquid electrolyte to which a coagulation factor and the like are added in a certain method and infiltrated; after the infiltration is completed, the liquid electrolyte adsorbed in the pores of the diaphragm is converted into a gel (or quasi-gel) electrolyte in a certain manner, and then frozen; the diaphragm adsorbed with the gel (or quasi-gel) electrolyte is frozen, and then sliced ​​to obtain the sliced ​​and frozen diaphragm electrolyte group (7); then the diaphragm is stacked with other components of the battery cell in a certain method, and then thawed to obtain the diaphragm electrolyte group (7) inside the battery cell; the bipolar lithium battery cell is injected and infiltrated on the outside of the battery cell.

8. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The bipolar lithium battery cell is composed of the positive electrode current collector (3) coated with the positive electrode material (4), two or more separator electrolyte groups (7), two or more intermediate current collectors (5) with the positive electrode material (4) or the negative electrode material (6) coated on both sides respectively, and a negative electrode current collector (8) coated with the negative electrode material (6) which are stacked in sequence.

9. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The positive electrode material (4) coated by the positive electrode collector (3) is stacked with the separator electrolyte group (7) at the back (or a similar back), and then the negative electrode material (6) coated by the intermediate current collector (5) is stacked at the back (or a similar back); the positive electrode material (4) coated by the intermediate current collector (5) is stacked with the separator electrolyte group (7), and then the separator electrolyte group (7) is stacked with the negative electrode material (6) coated by the next intermediate current collector (5); the positive electrode material (4) coated by the intermediate current collector (5) is stacked with the separator electrolyte group (7) at the back (or a similar back), and then the separator electrolyte group (7) is stacked with the negative electrode material (6) coated by the negative electrode collector (8) at the back (or a similar back).

10. A bipolar lithium battery cell according to any one of the preceding claims, characterized in that: The bipolar lithium battery cell has no tabs inside.

Images