Battery cell and method for manufacturing battery cell

Abstract

A battery cell (100) includes: a battery element (110); an electrolytic solution; at least one lid material (120) for at least partially covering the battery element (110); at least one conductor (130) electrically connected to the battery element (110); and an exterior film (140) wound around the battery element (110) and the at least one lid material (120). The at least one lid material (120) and / or the at least one conductor (130) defines a first through-hole (152a), a second through-hole (152b), a third through-hole (152c), and a fourth through-hole (152d) which are defined by the at least one lid material (120) and the exterior film (140) and communicate with a housing space (150) for housing the battery element (110) and the electrolytic solution.

Description

Battery Cell and Method for Manufacturing the Same

[0001] The present invention relates to a battery cell and a method for manufacturing the battery cell.

[0002] In recent years, various battery cells have been developed. A battery cell may include a battery element, at least one lid member that at least partially covers the battery element, and an exterior film wound around the battery element and the at least one lid member.

[0003] Patent Document 1 describes a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery includes a container, an electrode body housed in the container, a non-aqueous electrolyte housed in the container, and a sealing member provided at an opening of the container. A liquid injection port is provided on one of the bottom of the container and the sealing member. A hole that functions as an exhaust port during liquid injection is provided on the other of the bottom of the container and the sealing member.

[0004] Patent Document 2 describes a liquid injection device for a non-aqueous secondary battery including an electrolytic solution, an electrode laminate, and a battery can that houses the electrolytic solution and the electrode laminate. The battery can has an injection port for injecting the electrolytic solution into the interior of the battery can and an exhaust port for exhausting gas inside the battery can.

[0005] JP-A-2005-251738 JP-A-2014-22336

[0006] In a battery cell, the battery element and the electrolytic solution may be housed in a space defined by at least one lid member that at least partially covers the battery element and an exterior film wound around the battery element and the at least one lid member. In the method for manufacturing the battery cell, after injecting the electrolytic solution into the space from an unsealed portion of the exterior film, the unsealed portion of the exterior film may be sealed. However, when the unsealed portion of the exterior film is sealed after injecting the electrolytic solution into the space, it may be difficult to achieve an airtight seal of the battery element and the electrolytic solution due to the adhesion of the electrolytic solution to the unsealed portion of the exterior film.

[0007] One example of the object of the present invention is to hermetically seal a battery element and an electrolyte with at least one cover material that at least partially covers the battery element and an outer film wrapped around the battery element and the at least one cover material. Other objects of the present invention will become apparent from the description herein.

[0008] One aspect of the present invention is as follows: 1. A battery cell comprising: a battery element; an electrolyte; at least one lid material that at least partially covers the battery element; at least one conductor electrically connected to the battery element; and an outer film wrapped around the battery element and the at least one lid material, wherein at least one of the at least one lid material and the at least one conductor defines a plurality of through holes that communicate with a space defined by the at least one lid material and the outer film and that houses the battery element and the electrolyte. 2. The battery cell according to 1, wherein the plurality of through holes include at least two through holes defined by the at least one lid material. 3. The battery cell according to 1, wherein the plurality of through holes include at least two through holes defined by the at least one conductor. 4. The battery cell according to 1, wherein the plurality of through holes include at least one through hole defined by the at least one lid material and at least one through hole defined by the at least one conductor. 5. 1. to 4. A battery cell according to any one of the following, wherein the plurality of through holes include at least two through holes defined by at least one of the lid material and the conductor located on one of the sides of the battery element, and at least two other through holes defined by at least one of the lid material and the conductor located on the other side of the battery element. 6. A battery cell according to any one of the following, wherein the lid material is at least partially made of resin. 7. A battery cell according to any one of the following, wherein the plurality of through holes includes at least one through hole for injecting the electrolyte into the space, and at least one other through hole for discharging gas from the space. 8. A battery cell according to the following, wherein the plurality of through holes includes at least one through hole penetrating the lid material and the conductor located on one of the sides of the battery element, and at least one other through hole penetrating the lid material and the conductor located on the other side of the battery element.9. The battery cell according to 1, wherein the plurality of through holes include at least two through holes that penetrate the cover material and the conductor located on one of the sides of the battery element, and the plurality of through holes are not provided in the cover material and the conductor located on the other side of the battery element. 10. A method for manufacturing a battery cell, comprising the step of forming a space for housing the battery element and an electrolyte by comprising at least one cover material that at least partially covers the battery element and an outer film wrapped around the battery element and the at least one cover material, wherein the step of forming the space comprises the steps of injecting the electrolyte into the space through at least one through hole defined by at least one of the at least one cover material and at least one conductor electrically connected to the battery element, and discharging gas from the space through at least one other through hole defined by at least one of the at least one cover material and the at least one conductor. 11. The battery cell according to 10, wherein the at least one through hole and the at least one other through hole include at least two through holes defined by the at least one cover material. A method for manufacturing a battery cell as described in 10. 12. The method for manufacturing a battery cell as described in 10., wherein the at least one through-hole and the at least one other through-hole include at least two through-holes defined by the at least one conductor. 13. The method for manufacturing a battery cell as described in 10., wherein the at least one through-hole and the at least one other through-hole include at least one through-hole defined by the at least one cover material and at least one through-hole defined by the at least one conductor.14. A method for manufacturing a battery cell according to any one of 10 to 13, wherein the at least one through-hole for injecting the electrolyte includes a through-hole defined by at least one of the lid material and the conductor located on one of the sides of the battery element and a through-hole defined by at least one of the lid material and the conductor located on the other side of the battery element, and the at least one other through-hole for discharging the gas includes a through-hole defined by at least one of the lid material and the conductor located on one of the sides of the battery element and a through-hole defined by at least one of the lid material and the conductor located on the other side of the battery element. 15. A method for manufacturing a battery cell according to any one of 10 to 14, wherein the steps of injecting the electrolyte and discharging the gas are performed at least partially simultaneously. 16. The method for manufacturing a battery cell according to 10., wherein the at least one through-hole and the at least one other through-hole include at least one through-hole that penetrates the lid material and the conductor located on one of the sides of the battery element, and at least one other through-hole that penetrates the lid material and the conductor located on the other of the sides of the battery element. 17. The method for manufacturing a battery cell according to 10., wherein the at least one through-hole and the at least one other through-hole include at least two through-holes that penetrate the lid material and the conductor located on one of the sides of the battery element, and the at least one through-hole and the at least one other through-hole are not provided in the lid material and the conductor located on the other of the sides of the battery element.

[0009] According to the above embodiment of the present invention, the battery element and the electrolyte can be airtightly sealed by at least one lid material that at least partially covers the battery element, and an outer film wrapped around the battery element and the at least one lid material.

[0010] This is a perspective view of a battery cell according to an embodiment. This is a schematic cross-sectional view of the virtual plane α shown in Figure 1. This is a diagram illustrating a first example of a method for manufacturing a battery cell according to an embodiment. This is a diagram illustrating a second example of a method for manufacturing a battery cell according to an embodiment. This is a diagram illustrating a method for manufacturing a battery cell according to Modification 1. This is a diagram illustrating a method for manufacturing a battery cell according to Modification 2. This is a diagram illustrating a method for manufacturing a battery cell according to Modification 3. This is a schematic cross-sectional view of a battery cell according to Modification 4.

[0011] Embodiments and modified examples of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0012] Figure 1 is a perspective view of a battery cell 100 according to an embodiment. Figure 2 is a schematic cross-sectional view of the virtual plane α shown in Figure 1.

[0013] Each figure shows the X, Y, and Z directions for illustrative purposes. The X direction indicates the front-to-back direction of the battery cell 100. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery cell 100. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-to-down direction of the battery cell 100. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the rear, right, and up directions of the battery cell 100, respectively. The relationship between the X, Y, and Z directions and the front-to-back, left-to-right, and up-to-down directions of the battery cell 100 is not limited to the examples given in the embodiment.

[0014] Unless otherwise specified, the +X side refers to the side indicated by the X-axis arrow, and the -X side refers to the opposite side of the side indicated by the X-axis arrow. Unless otherwise specified, the +Y side refers to the side indicated by the Y-axis arrow, and the -Y side refers to the opposite side of the side indicated by the Y-axis arrow. Unless otherwise specified, the +Z side refers to the side indicated by the Z-axis arrow, and the -Z side refers to the opposite side of the side indicated by the Z-axis arrow. In Figure 2, the white circle with an X indicating the Y direction indicates that the Y-axis arrow indicating the Y direction is pointing towards the back of the paper.

[0015] The virtual plane α shown in Figures 1 and 2 is a plane perpendicular to the Y direction at approximately the center of the battery cell 100 in the Y direction according to the embodiment.

[0016] As shown in Figures 1 and 2, the battery cell 100 according to this embodiment comprises a battery element 110, a pair of cover materials 120, a pair of conductors 130, and an outer film 140.

[0017] The battery element 110 has a positive electrode, a negative electrode, and a separator (not shown). The battery element 110 has a substantially rectangular parallelepiped shape with length in the X direction, width in the Z direction, and height in the Y direction. The width of the battery element 110 in the Z direction is less than the length of the battery element 110 in the X direction and greater than the height of the battery element 110 in the Y direction. The shape of the battery element 110 is not limited to the example described herein. The battery cell 100 may consist of a single battery element 110 or a plurality of battery elements 110 stacked in the Y direction. As shown in Figure 2, a positive electrode current collector 112 is drawn out from the battery element 110 toward the -X side. The positive electrode and the positive electrode current collector 112 of the battery element 110 are electrically connected to each other. As shown in Figure 2, a negative electrode current collector 114 is drawn out from the battery element 110 toward the +X side. The negative electrode and the negative electrode current collector 114 of the battery element 110 are electrically connected to each other.

[0018] As shown in Figure 2, the pair of cover materials 120 are located on both sides of the battery element 110 in the X direction. Each cover material 120 covers the battery element 110 at least partially. Each cover material 120 is, for example, an insulator. Each cover material 120 is made of resin at least partially. When the cover material 120 is made of resin, it is easier to mold the cover material 120 compared to when the cover material 120 is made of metal.

[0019] Hereafter, unless otherwise specified, the first lid material 120a and the second lid material 120b refer to the lid material 120 on the -X side and the lid material 120 on the +X side, respectively. As shown in Figure 2, the first lid material 120a has a first lid base material 122a, a first external projection 124a, and a first internal projection 126a. As shown in Figure 2, the second lid material 120b has a second lid base material 122b, a second external projection 124b, and a second internal projection 126b. The second lid base material 122b, the second external projection 124b, and the second internal projection 126b correspond to the first lid base material 122a, the first external projection 124a, and the first internal projection 126a, respectively.

[0020] The first lid base material 122a has a substantially plate shape perpendicular to the X direction. The first lid base material 122a covers the X-side end face of the battery element 110. Viewed from the X direction, the first lid base material 122a has a substantially rectangular shape with a pair of short sides extending in the Y direction and a pair of long sides extending in the Z direction.

[0021] The first external projection 124a is located on the side opposite to the first lid substrate 122a where the battery element 110 is located. The first external projection 124a protrudes toward the -X direction from the entire circumference of the -X side surface of the first lid substrate 122a in the X direction. However, the first external projection 124a may be located only partially around the entire circumference of the first lid substrate 122a in the X direction, rather than over the entire circumference of the first lid substrate 122a in the X direction.

[0022] The first internal projection 126a is located on the side of the first lid base material 122a where the battery element 110 is located. The first internal projection 126a protrudes toward the +X side from the entire circumference of the +X side surface of the first lid base material 122a in the X direction. However, the first internal projection 126a may be located only partially around the entire circumference of the first lid base material 122a in the X direction, rather than over the entire circumference of the first lid base material 122a in the X direction.

[0023] The second lid 120b can be made in the same way as the first lid 120a, except that the first lid 120a and the second lid 120b are arranged substantially symmetrically.

[0024] As shown in Figure 2, the pair of conductors 130 are located on both sides of the battery element 110 in the X direction. Each conductor 130 and the battery element 110 are electrically connected to each other.

[0025] Hereafter, unless otherwise specified, the first conductor 130a and the second conductor 130b refer to the conductor 130 on the -X side and the conductor 130 on the +X side, respectively. As shown in Figure 2, the first conductor 130a has a first barrier layer 132a, a first external terminal 134a, and a first internal terminal 136a. As shown in Figure 2, the second conductor 130b has a second barrier layer 132b, a second external terminal 134b, and a second internal terminal 136b. The second barrier layer 132b, the second external terminal 134b, and the second internal terminal 136b correspond to the first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a, respectively.

[0026] The first barrier layer 132a is a layer perpendicular to the X direction. The first barrier layer 132a is a conductor, such as a metal layer. The first lid substrate 122a and the first barrier layer 132a overlap each other at least partially in the X direction. The first barrier layer 132a is at least partially located between the first lid substrate 122a and the battery element 110. The water vapor permeability of the first barrier layer 132a is less than that of the first lid substrate 122a. Therefore, the first barrier layer 132a can block the permeation of moisture from the first lid material 120a to the battery element 110. The first internal projection 126a is at least partially located around the first barrier layer 132a in the X direction. Therefore, the first barrier layer 132a can be positioned or held by the first internal projection 126a.

[0027] The first external terminal 134a is, for example, a conductor such as a metal block. The first external terminal 134a is located on the opposite side of the first barrier layer 132a from the side where the battery element 110 is located. The first external terminal 134a is a projection that protrudes toward the -X side from approximately the center of the -X side surface of the first barrier layer 132a. However, the first external terminal 134a may protrude toward the -X side from a portion offset from approximately the center of the -X side surface of the first barrier layer 132a. The first external terminal 134a penetrates the first lid base material 122a in the X direction and is drawn out toward the -X side from the -X side surface of the first lid base material 122a. Therefore, the first external terminal 134a can be electrically connected to a conductor such as a busbar (not shown) provided outside the battery cell 100. In this embodiment, compared to the case where the first conductor 130a does not have a first external terminal 134a, it is possible to electrically connect the first conductor 130a and a conductor such as a busbar to each other. Therefore, in this embodiment, the function of the first conductor 130a can be improved compared to the case where the first conductor 130a does not have a first external terminal 134a.

[0028] The second conductor 130b is arranged substantially symmetrically with respect to the first conductor 130a and can be similar to the first conductor 130a, except that the first conductor 130a and the second conductor 130b contain different materials as needed.

[0029] The outer film 140 is wrapped around the battery element 110 and the pair of cover materials 120 in the X direction. The outer film 140 is, for example, a laminate film.

[0030] The outer circumferential surfaces of the first lid base material 122a, the first external projection 124a, and the first internal projection 126a around the X direction, and the inner circumferential surfaces of the portions of the first lid base material 122a, the first external projection 124a, and the first internal projection 126a of the outer film 140 around the X direction, are at least partially joined to each other by joining, for example, heat fusion. Therefore, the battery cell 100 has a sealing portion on the -X side formed by the -X side ends of the first lid material 120a and the -X side ends of the outer film 140. The outer circumferential surfaces of the second lid base material 122b, the second external projection 124b, and the second internal projection 126b around the X direction, and the inner circumferential surfaces of the portions of the second lid base material 122b, the second external projection 124b, and the second internal projection 126b of the outer film 140 around the X direction, are at least partially joined to each other by joining, for example, heat fusion. Therefore, the battery cell 100 further has a sealing portion on the +X side formed by the second cover material 120b and the +X side end of the outer film 140. The battery cell 100 further has another sealing portion that extends in the X direction from one sealing portion on both sides in the X direction to the other. This other sealing portion is formed when the excess length portions drawn out from the wrapped portions of the outer film 140 and the battery element 110 and the pair of cover materials 120 are joined to each other by bonding such as heat fusion.

[0031] A pair of lid materials 120 and an outer film 140 define a housing space 150 for housing the battery element 110 and the electrolyte. The housing space 150 is sealed by sealing portions on both sides of the battery cell 100 in the X direction and by other sealing portions extending from one side of the sealing portion on both sides of the battery cell 100 in the X direction to the other.

[0032] As shown in Figure 2, the first lid base material 122a and the first barrier layer 132a define a first through hole 152a and a second through hole 152b. The first through hole 152a and the second through hole 152b are located on the +Z side and -Z side with respect to the first external terminal 134a and the first internal terminal 136a, respectively. The first through hole 152a penetrates the +Z side portion of the first lid base material 122a and the first barrier layer 132a in the X direction and communicates with the +Z side portion of the -X side end of the housing space 150. The second through hole 152b penetrates the -Z side portion of the first lid base material 122a and the first barrier layer 132a in the X direction and communicates with the -Z side portion of the -X side end of the housing space 150. As shown in Figure 2, the first through hole 152a and the second through hole 152b are blocked by the first plug 154a and the second plug 154b, respectively. Therefore, the electrolyte in the containment space 150 can be prevented from leaking out of the containment space 150 through the first through-hole 152a and the second through-hole 152b.

[0033] As shown in Figure 2, the second lid base material 122b and the second barrier layer 132b define a third through hole 152c and a fourth through hole 152d. The third through hole 152c and the fourth through hole 152d are located on the +Z side and -Z side, respectively, with respect to the second external terminal 134b and the second internal terminal 136b. The third through hole 152c penetrates the +Z side portion of the second lid base material 122b and the second barrier layer 132b in the X direction and communicates with the +Z side portion of the +X side end of the housing space 150. The fourth through hole 152d penetrates the -Z side portion of the second lid base material 122b and the second barrier layer 132b in the X direction and communicates with the -Z side portion of the +X side end of the housing space 150. As shown in Figure 2, the third through hole 152c and the fourth through hole 152d are blocked by the third plug 154c and the fourth plug 154d, respectively. Therefore, the electrolyte in the containment space 150 can be prevented from leaking out of the containment space 150 through the third through-hole 152c and the fourth through-hole 152d.

[0034] At least one of the first plug 154a, second plug 154b, third plug 154c, and fourth plug 154d may be removable. Due to the use of the battery cell 100 for a certain period of time, the electrolyte in the housing space 150 may decrease. If the electrolyte in the housing space 150 decreases, the capacity of the battery cell 100 can be restored by replenishing the electrolyte through the through-hole from which the above-mentioned plug has been removed. Before restoring the capacity of the battery cell 100, the battery cell 100 may be used in an electric vehicle. Even if it is difficult to use the battery cell 100 in an electric vehicle after restoring its capacity, the battery cell 100 may be usable in a battery where a lower capacity than that required for an electric vehicle is acceptable, such as a stationary battery. However, the first plug 154a, second plug 154b, third plug 154c, and fourth plug 154d may not be removable.

[0035] Figure 3 is a diagram illustrating a first example of a method for manufacturing a battery cell 100 according to an embodiment.

[0036] In Figure 3, the solid arrows extending toward the second through-hole 152b and the solid arrows extending toward the fourth through-hole 152d schematically represent the flow of electrolyte injected into the containment space 150 through the second through-hole 152b and the flow of electrolyte injected into the containment space 150 through the fourth through-hole 152d, respectively. In Figure 3, the dashed arrows extending from the first through-hole 152a and the dashed arrows extending from the third through-hole 152c schematically represent the flow of gas discharged from the containment space 150 through the first through-hole 152a and the flow of gas discharged from the containment space 150 through the third through-hole 152c, respectively. In Figure 3, the +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction.

[0037] In the first example, the battery cell 100 according to the embodiment is manufactured as follows.

[0038] First, the first cover material 120a and the first conductor 130a are attached to each other so that the first external terminal 134a penetrates the first cover base material 122a. Similarly, the second cover material 120b and the second conductor 130b are attached to each other so that the second external terminal 134b penetrates the second cover base material 122b. Next, the positive electrode current collector 112 and the first internal terminal 136a are joined to each other to electrically connect the battery element 110 and the first conductor 130a. Similarly, the negative electrode current collector 114 and the second internal terminal 136b are joined to each other to electrically connect the battery element 110 and the second conductor 130b. In the above description, the battery element 110 and the conductor 130 are electrically connected to each other after the cover material 120 and the conductor 130 are attached to each other. However, the cover material 120 and the conductor 130 may be attached to each other after the battery element 110 and the conductor 130 are electrically connected to each other.

[0039] Next, the outer film 140 is wrapped around the battery element 110 and the pair of cover materials 120 around the X direction. Then, the outer circumferential surfaces of the first cover base material 122a, the first external projection 124a, and the first internal projection 126a around the X direction and the inner circumferential surfaces of the portions of the first cover base material 122a, the first external projection 124a, and the first internal projection 126a of the outer film 140 around the X direction are joined at least partially to each other by joining, for example, heat fusion, to form the -X side sealing portion of the battery cell 100. Furthermore, the outer circumferential surfaces of the second cover base material 122b, the second external projection 124b, and the second internal projection 126b around the X direction and the inner circumferential surfaces of the portions of the second cover base material 122b, the second external projection 124b, and the second internal projection 126b of the outer film 140 around the X direction are joined at least partially to each other by joining, for example, heat fusion, to form the +X side sealing portion of the battery cell 100. Furthermore, the excess portions of the outer film 140 that have been pulled out from the wrapped portions of the battery element 110 and the pair of lid materials 120 are joined together by means of bonding such as heat fusion, thereby forming another sealing portion that extends in the X direction from one sealing portion on both sides of the battery cell 100 in the X direction to the other. These sealing portions form a housing space 150 for housing the battery element 110.

[0040] Next, as shown in Figure 3, electrolyte is injected into the containment space 150 through the second through-hole 152b and the fourth through-hole 152d, and gas is discharged from the containment space 150 through the first through-hole 152a and the third through-hole 152c. By injecting electrolyte into the containment space 150 through the second through-hole 152b and the fourth stopper 154d, the containment space 150 can be filled with electrolyte. By discharging gas from the containment space 150 through the first through-hole 152a and the third through-hole 152c, the containment space 150 can be evacuated.

[0041] The injection of electrolyte into the containment space 150 through the second through-hole 152b and the fourth through-hole 152d, and the discharge of gas from the containment space 150 through the first through-hole 152a and the third through-hole 152c are performed at least partially simultaneously. Therefore, compared to the case where the injection of electrolyte into the containment space 150 through the second through-hole 152b and the fourth through-hole 152d, and the discharge of gas from the containment space 150 through the first through-hole 152a and the third through-hole 152c are performed with a time difference, the injection of electrolyte into the containment space 150 can be accelerated, and the electrolyte can be more easily impregnated into the battery element 110. However, the injection of electrolyte into the containment space 150 through the second through-hole 152b and the fourth through-hole 152d, and the discharge of gas from the containment space 150 through the first through-hole 152a and the third through-hole 152c may be performed with a time difference.

[0042] In the example shown in Figure 3, the electrolyte is injected into the lower part of the containment space 150 through the second through-hole 152b and the fourth through-hole 152d. The electrolyte accumulates from the lower part of the containment space 150. Therefore, in the example shown in Figure 3, it is possible to impregnate the battery element 110 with the electrolyte more easily than if the electrolyte were injected into the upper part of the containment space 150 through the first through-hole 152a and the third through-hole 152c. However, the electrolyte may also be injected into the upper part of the containment space 150 through the first through-hole 152a and the third through-hole 152c.

[0043] In the example shown in FIG. 3, the gas is discharged from the upper part of the accommodation space 150 through the first through hole 152a and the third through hole 152c. The electrolytic solution accumulates from the lower part of the accommodation space 150. Therefore, in the example shown in FIG. 3, it is possible to suppress the discharge of the electrolytic solution together with the gas rather than discharging the gas from the lower part of the accommodation space 150 through the second through hole 152b and the fourth through hole 152d. However, the gas may be discharged through the second through hole 152b and the fourth through hole 152d.

[0044] After the injection of the electrolytic solution into the accommodation space 150 and the discharge of the gas from the accommodation space 150 are completed, the first through hole 152a, the second through hole 152b, the third through hole 152c, and the fourth through hole 152d are respectively blocked by the first plug 154a, the second plug 154b, the third plug 154c, and the fourth plug 154d. By blocking these through holes with these plugs, the battery cell 100 and the accommodation space 150 for accommodating the electrolytic solution are formed.

[0045] In the embodiment, the electrolytic solution is injected into the accommodation space 150 through the through hole defined by the lid member 120. Therefore, compared with the case where the unsealed portion of the outer film 140 is sealed after injecting the electrolytic solution into the accommodation space 150 from the unsealed portion of the outer film 140, it is possible to suppress the adhesion of the electrolytic solution to the unsealed portion of the outer film 140, and the battery element 110 and the electrolytic solution can be hermetically sealed. Specifically, as described above, in the embodiment, the surplus length portions drawn from the winding portions of the battery element 110 and the pair of lid members 120 of the outer film 140 are joined to each other by joining such as heat fusion, for example, to form another sealing portion extending in the X direction from one side to the other side of the sealing portions on both sides in the X direction of the battery cell 100. If the electrolytic solution is injected into the accommodation space 150 from between the surplus length portions of the outer film 140, it may be difficult to hermetically seal the battery element 110 and the electrolytic solution due to the adhesion of the electrolytic solution to the surplus length portions of the outer film 14%. However, in the embodiment, after joining the surplus length portions of the outer film 140 to each other, the electrolytic solution is injected into the accommodation space 150. Therefore, compared with the case where the electrolytic solution is injected into the accommodation space 150 from between the surplus length portions of the outer film 140, the battery element 110 and the electrolytic solution can be hermetically sealed.

[0046] In an embodiment, the pair of lid members 120 define a plurality of through holes including a first through hole 152a, a second through hole 152b, a third through hole 152c, and a fourth through hole 152d. Therefore, at least one of the plurality of through holes can function as a through hole for injecting an electrolytic solution into the accommodation space 150, and at least one of the other plurality of through holes can function as a through hole for discharging gas from the accommodation space 150.

[0047] In an embodiment, the first lid member 120a defines at least two through holes including the first through hole 152a and the second through hole 152b, and the second lid member 120b defines at least two other through holes including the third through hole 152c and the fourth through hole 152d. Accordingly, the electrolytic solution can be injected into the accommodation space 150 from both sides in the X direction of the accommodation space 150, and gas can be discharged from the accommodation space 150 toward both sides in the X direction of the accommodation space 150. Therefore, compared with the case where the electrolytic solution is injected into the accommodation space 150 only from one of both sides in the X direction of the accommodation space 150 or the case where gas is discharged from the accommodation space 150 only to one of both sides in the X direction of the accommodation space 150, the injection of the electrolytic solution into the accommodation space 150 and the discharge of gas from the accommodation space 150 can be accelerated.

[0048] The function of the through hole defined by the lid member 120 is not limited to the functions described above. For example, the through hole may function as at least a part of a gas release valve that opens when the pressure in the accommodation space 150 becomes equal to or higher than a certain value due to factors such as an abnormality in the battery cell 100.

[0049] FIG. 4 is a diagram for explaining a second example of a method for manufacturing the battery cell 100 according to the embodiment. The second example of the method for manufacturing the battery cell 100 according to the embodiment is the same as the first example of the method for manufacturing the battery cell 100 according to the embodiment, except for the following points.

[0050] In Figure 4, the solid arrows extending toward the first through-hole 152a and the solid arrows extending toward the second through-hole 152b schematically represent the flow of electrolyte injected into the containment space 150 through the first through-hole 152a and the flow of electrolyte injected into the containment space 150 through the second through-hole 152b, respectively. In Figure 4, the dashed arrows extending from the third through-hole 152c and the dashed arrows extending from the fourth through-hole 152d schematically represent the flow of gas discharged from the containment space 150 through the third through-hole 152c and the flow of gas discharged from the containment space 150 through the fourth through-hole 152d, respectively. In Figure 4, the +X side is the upper side in the vertical direction, and the -X side is the lower side in the vertical direction.

[0051] As shown in Figure 4, the electrolyte may be injected into the lower part of the containment space 150 through the first through-hole 152a and the second through-hole 152b, and the gas may be discharged from the upper part of the containment space 150 through the third through-hole 152c and the fourth through-hole 152d. In the example shown in Figure 4, as in the example shown in Figure 3, the battery element 110 and the electrolyte can be hermetically sealed by using the first through-hole 152a, the second through-hole 152b, the third through-hole 152c and the fourth through-hole 152d.

[0052] Figure 5 is a diagram illustrating the manufacturing method of the battery cell 100A according to Modification 1. The battery cell 100A according to Modification 1 is the same as the battery cell 100 according to the embodiment, except for the following points.

[0053] In Figure 5, the solid arrow extending toward the second through-hole 152b schematically shows the flow of electrolyte injected into the containment space 150 through the second through-hole 152b. In Figure 5, the dashed arrow extending from the third through-hole 152c schematically shows the flow of gas discharged from the containment space 150 through the third through-hole 152c. In Figure 5, the +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction.

[0054] The battery cell 100A according to Modification 1 does not have through holes corresponding to the first through hole 152a and the fourth through hole 152d of the battery cell 100 according to Embodiment 1, and has a second through hole 152b and a third through hole 152c, similar to the battery cell 100 according to Embodiment 1. In the example shown in Figure 5, the second plug 154b that blocks the second through hole 152b and the third plug 154c that blocks the third through hole 152c have been removed.

[0055] As shown in Figure 5, the electrolyte may be injected into the lower part of the -X side end of the housing space 150 through the second through hole 152b, or the gas may be discharged from the upper part of the +X side end of the housing space 150 through the third through hole 152c. In the example shown in Figure 5, as in the embodiment, the battery element 110 and the electrolyte can be hermetically sealed by using the second through hole 152b and the third through hole 152c.

[0056] Figure 6 is a diagram illustrating the manufacturing method of the battery cell 100B according to Modification 2. The battery cell 100B according to Modification 2 is the same as the battery cell 100 according to the embodiment, except for the following points.

[0057] In Figure 6, the solid arrow extending toward the first through-hole 152a schematically shows the flow of electrolyte injected into the containment space 150 through the first through-hole 152a. In Figure 6, the dashed arrow extending from the third through-hole 152c schematically shows the flow of gas discharged from the containment space 150 through the third through-hole 152c. In Figure 6, the +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction.

[0058] The battery cell 100B according to Modification 2 does not have through holes corresponding to the second through hole 152b and the fourth through hole 152d of the battery cell 100 according to Embodiment 1, and has a first through hole 152a and a third through hole 152c, similar to the battery cell 100 according to Embodiment 1. In the example shown in Figure 6, the first plug 154a that closes the first through hole 152a and the third plug 154c that closes the third through hole 152c have been removed.

[0059] As shown in Figure 6, the electrolyte may be injected into the upper part of the -X side end of the containment space 150 through the first through-hole 152a, or the gas may be discharged from the upper part of the +X side end of the containment space 150 through the third through-hole 152c. In the example shown in Figure 6, as in the embodiment, the battery element 110 and the electrolyte can be hermetically sealed by using the first through-hole 152a and the third through-hole 152c.

[0060] Figure 7 is a diagram illustrating the manufacturing method of the battery cell 100C according to Modification 3. The battery cell 100C according to Modification 3 is the same as the battery cell 100 according to the embodiment, except for the following points.

[0061] In Figure 7, the solid arrow extending toward the third through-hole 152c schematically shows the flow of electrolyte injected into the containment space 150 through the third through-hole 152c. In Figure 7, the dashed arrow extending from the fourth through-hole 152d schematically shows the flow of gas discharged from the containment space 150 through the fourth through-hole 152d. In Figure 7, the +X side is the upper side in the vertical direction, and the -X side is the lower side in the vertical direction.

[0062] The battery cell 100C according to Modification 3 does not have through holes corresponding to the first through hole 152a and the second through hole 152b of the battery cell 100 according to Embodiment 1, and has a third through hole 152c and a fourth through hole 152d, similar to the battery cell 100 according to Embodiment 1. In the example shown in Figure 7, the third plug 154c that blocks the third through hole 152c and the fourth plug 154d that blocks the fourth through hole 152d have been removed.

[0063] As shown in Figure 7, the electrolyte may be injected into the upper +Z side portion of the housing space 150 through the third through-hole 152c, or the gas may be discharged from the upper -Z side portion of the housing space 150 through the fourth through-hole 152d. In the example shown in Figure 7, the battery element 110 and the electrolyte can be hermetically sealed in the same manner as in the embodiment.

[0064] Figure 8 is a schematic cross-sectional view of the battery cell 100D according to Modification 4. The virtual plane α in Modification 4 shown in Figure 8 is a plane perpendicular to the Y direction at approximately the center of the battery cell 100D in the Y direction, similar to the virtual plane α in the embodiment shown in Figures 1 and 2. The battery cell 100D according to Modification 4 is the same as the battery cell 100 according to the embodiment, except for the following points.

[0065] In the modified example 4, the first conductor 130a defines a fifth through-hole 152e. The fifth through-hole 152e penetrates the first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a in the X direction. In the example shown in Figure 8, the fifth through-hole 152e is located approximately in the center of the first conductor 130a in the Z direction. Therefore, the fifth through-hole 152e communicates with approximately in the center of the -X side end of the housing space 150 in the Z direction. The number and arrangement of the fifth through-holes 152e are not limited to the example shown in Figure 8. For example, the first conductor 130a may define a plurality of fifth through-holes 152e.

[0066] A fifth plug 154e is embedded in the fifth through-hole 152e. Therefore, the fifth through-hole 152e is sealed by the fifth plug 154e. Thus, the fifth through-hole 152e can be sealed by the fifth plug 154e. Thus, the electrolyte in the containment space 150 can be prevented from leaking out of the containment space 150 through the fifth through-hole 152e. The fifth plug 154e is, for example, made of metal. In modified example 4, the inner circumferential surface of the first conductor 130a around the X direction of the fifth through-hole 152e and the outer circumferential surface of the fifth plug 154e around the X direction are welded to each other. Thus, the structure of the fifth through-hole 152e can be simplified compared to screwing the fifth plug 154e into the fifth through-hole 152e. When the fifth plug 154e is screwed into the fifth through-hole 152e, resin may be required to fill the space between the fifth through-hole 152e and the fifth plug 154e. In contrast, in this embodiment, the fifth through-hole 152e can be sealed by the fifth plug 154e without filling the space between the fifth through-hole 152e and the fifth plug 154e with resin. However, the fifth plug 154e may be a screw that can be screwed into the fifth through-hole 152e.

[0067] The second conductor 130b in Modification 4 defines a sixth through-hole 152f in the same manner as the first conductor 130a in Modification 4. The matters described for the fifth through-hole 152e are also applicable to the sixth through-hole 152f, except that the fifth through-hole 152e and the sixth through-hole 152f are arranged substantially symmetrically. The sixth through-hole 152f in Modification 4 is sealed by a sixth plug 154f in the same manner as the fifth through-hole 152e in Modification 4. The matters described for the fifth plug 154e are also applicable to the sixth plug 154f, except that the fifth plug 154e and the sixth plug 154f are arranged substantially symmetrically.

[0068] By using not only the through-holes provided in the lid material 120 but also the through-holes provided in the conductor 130, the electrolyte can be injected into the containment space 150 more efficiently, and the gas can be discharged from the containment space 150 more efficiently. Specifically, the electrolyte can be injected into the containment space 150 using at least one of the first through-holes 152a, second through-hole 152b, third through-hole 152c, fourth through-hole 152d, fifth through-hole 152e, and sixth through-hole 152f, and the gas can be discharged from the containment space 150 using at least one other through-hole among the first through-hole 152a, second through-hole 152b, third through-hole 152c, fourth through-hole 152d, fifth through-hole 152e, and sixth through-hole 152f. For example, electrolyte may be injected into the containment space 150 through both the fifth through-hole 152e and the sixth through-hole 152f, or gas may be discharged from the containment space 150 through both the fifth through-hole 152e and the sixth through-hole 152f. Alternatively, electrolyte may be injected into the containment space 150 through one of the fifth through-hole 152e and the sixth through-hole 152f, and gas may be discharged from the containment space 150 through the other of the fifth through-hole 152e and the sixth through-hole 152f.

[0069] In the modified example 4 shown in Figure 8, through holes are defined in both the first conductor 130a and the second conductor 130b, which are sealed by plugs. However, the through holes may be provided in only one of the first conductor 130a and the second conductor 130b.

[0070] In the modified example 4 shown in Figure 8, both the lid material 120 and the conductor 130 define through holes sealed by plugs. However, the through holes may be provided only in the conductor 130 and not in the lid material 120. For example, with the first through hole 152a, second through hole 152b, third through hole 152c, and fourth through hole 152d not provided, the electrolyte may be injected into the containment space 150 using one of the fifth through hole 152e and sixth through hole 152f, and the gas may be discharged from the containment space 150 using the other of the fifth through hole 152e and fourth through hole 152d. If the lid material 120 does not have through holes, the first conductor 130a may define a plurality of fifth through holes 152e, and the second conductor 130b may define a plurality of sixth through holes 152f. For example, the multiple fifth through holes 152e may be located in multiple portions of the first conductor 130a that are offset from each other in the Z direction, and the multiple sixth through holes 152f may be located in multiple portions of the second conductor 130b that are offset from each other in the Z direction.

[0071] The embodiments and modifications of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0072] As illustrated in Embodiment, Modification 1, Modification 2, Modification 3 and Modification 4, at least one of the at least one lid material 120 and at least one conductor 130 can be configured to define a plurality of through holes communicating with the containment space 150. By defining a plurality of through holes with at least one of the at least one lid material 120 and at least one conductor 130, an electrolyte can be injected into the containment space 150 through at least one through hole defined by at least one of the at least one lid material 120 and at least one conductor 130, and gas can be discharged from the containment space 150 through at least one other through hole defined by at least one of the at least one lid material 120 and at least one conductor 130. For example, at least one through-hole for injecting electrolyte may include a through-hole defined by at least one of the first lid material 120a and the first conductor 130a, and a through-hole defined by at least one of the second lid material 120b and the second conductor 130b, and at least one other through-hole for discharging gas may include a through-hole defined by at least one of the first lid material 120a and the first conductor 130a, and a through-hole defined by at least one of the second lid material 120b and the second conductor 130b. That is, a plurality of through-holes may include two through-holes defined by at least one of the first lid material 120a and the first conductor 130a, and at least two through-holes defined by at least one of the second lid material 120b and the second conductor 130b.

[0073] As illustrated in Embodiment, Modification 1, Modification 2, and Modification 3, the plurality of through holes may include at least two through holes defined by at least one cover material 120. Alternatively, as illustrated in Modification 4, the plurality of through holes may include at least two through holes defined by at least one conductor 130. Alternatively, as illustrated in Modification 4, the plurality of through holes may include at least one through hole defined by at least one cover material 120 and at least one through hole defined by at least one conductor 130.

[0074] As illustrated in the embodiments shown in Figures 2 to 4, Modification 1 shown in Figure 5, Modification 2 shown in Figure 6, and Modification 4 shown in Figure 8, at least one through-hole may penetrate the cover material 120 and conductor 130 located on one of the sides of the battery element 110 in the X direction, and at least one other through-hole may penetrate the cover material 120 and conductor 130 located on the other side of the battery element 110 in the X direction. As illustrated in the embodiments shown in Figures 3 to 4, Modification 1 shown in Figure 5, and Modification 2 shown in Figure 6, electrolyte may be injected through at least one through-hole penetrating the cover material 120 and conductor 130 located on one of the sides of the battery element 110 in the X direction, and gas may be discharged through at least one other through-hole penetrating the cover material 120 and conductor 130 located on the other side of the battery element 110 in the X direction. Alternatively, as illustrated in Modification 3 shown in Figure 7, at least two through-holes may penetrate the lid 120 and conductor 130 located on one of the sides of the battery element 110 in the X direction, while the lid 120 and conductor 130 located on the other side of the battery element 110 in the X direction may not have through-holes. As illustrated in Modification 3 shown in Figure 7, electrolyte may be injected through the through-holes penetrating the lid 120 and conductor 130 located on one of the sides of the battery element 110 in the X direction, and gas may be discharged through other through-holes penetrating the lid 120 and conductor 130 located on that one side of the battery element 110 in the X direction.

[0075] In this embodiment, a pair of cover materials 120 are located on both sides of the battery element 110 in the X direction. However, the cover materials 120 may be located on only one side of the battery element 110 in the X direction. For example, if the cover material 120 is located only on the -X side of the battery element 110, the outer film 140 is folded on the +X side of the battery element 110 so that the +X end face of the battery element 110 is sealed. If the cover material 120 is located on only one side of the battery element 110 in the X direction, the cover material 120 defines at least one through-hole for injecting electrolyte into the containment space 150 and at least one other through-hole for venting gas from the containment space 150. Using these through-holes, the battery element 110 and the electrolyte can be hermetically sealed in the same manner as in this embodiment.

[0076] In this embodiment, each lid 120 defines two through holes. However, each lid 120 may define three or more through holes. Furthermore, each lid 120 may define a single through hole, as long as there are separate through holes for injecting electrolyte into the containment space 150 and for discharging gas from the containment space 150.

[0077] This application claims priority based on Japanese Patent Application No. 2024-185328, filed on 21 October 2024, and incorporates all of its disclosures herein.

[0078] 100, 100A, 100B, 100C, 100D Battery cell, 110 Battery element, 112 Positive electrode current collector, 114 Negative electrode current collector, 120 Cover material, 120a First cover material, 120b Second cover material, 122a First cover base material, 122b Second cover base material, 124a First external projection, 124b Second external projection, 126a First internal projection, 126b Second internal projection, 130 Conductor, 130a First conductor, 130b Second conductor, 132a First barrier layer, 132b Second barrier layer, 134a First external terminal, 134b Second external terminal, 136a First internal terminal, 136b Second internal terminal, 140 Outer film, 150 Housing space, 152a First through hole, 152b Second through hole, 152c 3rd through hole, 152d 4th through hole, 152e 5th through hole, 152f 6th through hole, 154a 1st plug, 154b 2nd plug, 154c 3rd plug, 154d 4th plug, 154e 5th plug, 154f 6th plug

Claims

1. A battery cell comprising: a battery element; an electrolyte; at least one lid material that at least partially covers the battery element; at least one conductor electrically connected to the battery element; and an outer film wrapped around the battery element and the at least one lid material, wherein at least one of the at least one lid material and the at least one conductor defines a plurality of through holes that communicate with a space defined by the at least one lid material and the outer film that houses the battery element and the electrolyte.

2. The battery cell according to claim 1, wherein the plurality of through holes include at least two through holes defined by the at least one cover material.

3. The battery cell according to claim 1, wherein the plurality of through holes include at least two through holes defined by the at least one conductor.

4. The battery cell according to claim 1, wherein the plurality of through holes include at least one through hole defined by the at least one cover material and at least one through hole defined by the at least one conductor.

5. The battery cell according to any one of claims 1 to 4, wherein the plurality of through holes include at least two through holes defined by at least one of the lid material and the conductor located on one of the sides of the battery element, and at least two other through holes defined by at least one of the lid material and the conductor located on the other side of the battery element.

6. The battery cell according to any one of claims 1 to 4, wherein the lid material is at least partially made of resin.

7. The battery cell according to any one of claims 1 to 4, wherein the plurality of through holes include at least one through hole for injecting the electrolyte into the space and at least one other through hole for discharging gas from the space.

8. The battery cell according to claim 1, wherein the plurality of through holes include at least one through hole located on one of the sides of the battery element that penetrates the cover material and the conductor, and at least one other through hole located on the other side of the battery element that penetrates the cover material and the conductor.

9. The battery cell according to claim 1, wherein the plurality of through holes include at least two through holes that penetrate the cover material and the conductor located on one of the sides of the battery element, and the plurality of through holes are not provided in the cover material and the conductor located on the other side of the battery element.

10. A method for manufacturing a battery cell, comprising the steps of forming a space for housing a battery element and an electrolyte by comprising at least one lid material that at least partially covers the battery element and an outer film wrapped around the battery element and the at least one lid material, wherein the step of forming the space comprises the steps of injecting the electrolyte into the space through at least one through-hole defined by at least one of the at least one of the at least one lid material and at least one conductor electrically connected to the battery element, and discharging gas from the space through at least one other through-hole defined by at least one of the at least one of the at least one lid material and the at least one conductor.

11. The method for manufacturing a battery cell according to claim 10, wherein the at least one through hole and the at least one other through hole include at least two through holes defined by the at least one cover material.

12. The method for manufacturing a battery cell according to claim 10, wherein the at least one through-hole and the at least one other through-hole include at least two through-holes defined by the at least one conductor.

13. The method for manufacturing a battery cell according to claim 10, wherein the at least one through-hole and the at least one other through-hole include at least one through-hole defined by the at least one cover material and at least one through-hole defined by the at least one conductor.

14. A method for manufacturing a battery cell according to any one of claims 10 to 13, wherein the at least one through-hole for injecting the electrolyte includes a through-hole defined by at least one of the lid material and the conductor located on one of the sides of the battery element and a through-hole defined by at least one of the lid material and the conductor located on the other side of the battery element, and the at least one other through-hole for discharging the gas includes a through-hole defined by at least one of the lid material and the conductor located on one of the sides of the battery element and a through-hole defined by at least one of the lid material and the conductor located on the other side of the battery element.

15. A method for manufacturing a battery cell according to any one of claims 10 to 13, wherein the steps of injecting the electrolyte and discharging the gas are performed at least partially simultaneously.

16. The method for manufacturing a battery cell according to claim 10, wherein the at least one through-hole and the at least one other through-hole include at least one through-hole that penetrates the cover material and the conductor located on one of the sides of the battery element, and at least one other through-hole that penetrates the cover material and the conductor located on the other of the sides of the battery element.

17. The method for manufacturing a battery cell according to claim 10, wherein the at least one through-hole and the at least one other through-hole include at least two through-holes that penetrate the cover material and the conductor located on one of the sides of the battery element, and the at least one through-hole and the at least one other through-hole are not provided in the cover material and the conductor located on the other side of the battery element.

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